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Handbook of testing - AB-BDI-BL

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1. 99 90 99 90 Weibull 100 000 mile car 100 000 mile car n W2 RRY SRM MED W2 RRY SRM MED 2 5 0 pA F 2 8 90 00 150 000 mile truck 90 00 150 000 mile truck W2 RRY SRM MED W2 RRY SRM MED F 3 S 0 3 5 Strength On Test Strength On Test j E 50 00 W2 50 00 W2 RRY SRM 1 5 0 1 8 0 gt 5 9 10 00 gt 00 D 5 00 00 Larry Edson Larry Edson eneral Mo tors Motors 1 00 8 23 2005 07 37 1 00 8 23 2005 07 44 1 00 10 00 100 00 1000 00 10000 00 100000 00 1 00 10 00 100 00 1000 00 10000 00 100000 00 Thermal Cycles Thermal Cycles a ee a tas gt h fili Fal t di E i ili Fili Hali dii R 99 8 98 2 R 99 1 mmm mmm mmm mmm R 99 796 R 99 8 98 2 99 1 A new scientific truth does not triumph by convincing its opponents and making them see the light but rather because its opponents eventually die and a new generation grows up that is familiar with it IH Max Plank Scientific Autobiography 99 GENERAL MOTORS CORPORATION EDSON 2008 THE REAL BIG PICTURE Summary The Overall Reliability Model Design In Adequate
2. 10 100 1000 10000 Frequency Hz Un Sprung Mass RMS Acceleration Grms 107 3 m s 10 95 Grms Table 25 Random Vibration Profile Unsprung Mass Power Spectral Density g Hz Acceleration Power Density m s Hz 0 005 0 031 0 031 Criteria Functional Status shall be class A No objectionable squeaks or rattles should be present before or after the vibration test The responsible GM engineer should evaluate the severity of all squeaks and rattles that develop following the vibration test GENERAL MOTORS CORPORATION EDSON 2008 Thermal Cycle Profile Used During All Vibration Tests The Thermal Cycle Profile Used During All Vibration Tests is intended to allow the vibration process to occur at all possible temperatures between Tmin and Tmax Some materials may significantly change their fatigue life with temperature and this combined test is effective in determining the severity of that possibility The graphic shows the product being turned on and off periodically In situations where turning the product off represents a significant problem then the product should remain on continuously during the test Note The intermittent powering off may be considered optional Because in vehicle vibration stress can occur together with extremely low or high temperatures Simultaneous temperature cycle has to be used during the vibra
3. 60 INTERCONNECT STRESS TESTIS TY TESTIN G 62 HALT HIGHLY ACCELERATED LIFE eene emen nene hse hene sensere nean 63 SUCCESS RUN TESTING pi Re Pare UE PAM RUNE 63 ML EE RM 64 sinc pests cs ceases 66 E 66 CHARACTERISTIC LIFE MEET 67 NEU DIAN EAN es TER 67 EVALUATION 68 SUDDEN DEATH TESTING 69 CALIBRATED ACCELERATED LIFE TESTING CALT 70 DEGRADATION ANALYSIS 71 OI 73 LEAD FREE SOLDER REQUIREMENT FOR NEW PRODUCTS IN 2009 74 THE PLAN OVERVIEW 81 MAJOR ELEMENTS THAT SHOULD INCLUDED IN THE 2 0040 0 0 000000000088 91 URN IR E Tc YY 91 ANALTHORSLT ects rs CE PME IM 94 ISEVELOPMENT 94 UN E
4. 192 HUMIDITY LESISINJIEVELOPMEN TE A EEEE 192 712 UAR E EE EO OU 192 Highly Accelerated Stress Test HAST For eee eere n ranas 194 DEVELOPMENT RESULTS REVIEW ocius odisea basso MSsc C dE ER SUPE brc cH as ede bos E cp Op tpa MUS 195 DESIGN VALIDATION ACTIVITIES e eee eee e e e e e eere eere eere eene 196 ELECTRICAL TRANSIENT ey Pe 196 gere 87101 rcr 196 Dolari or at Volane DTOD 200 Banery oou EP Oi 201 senn E EES 203 Sinusoidal Superimposed Voltage Test Beyond Normal 1 203 Pulse Superimposed Voltage Test Within Normal 204 C 205 Open Circuit Signal Line Single 206 Open Circuit Signal Line Multiple 206 Open C rocut Battery Line 206 Open Circuit Ground Line eis 207 Crona T Emm mm 208 1x00 22 CT 7772 2 2 2 24 000 209 Loau Over Curreri
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6. Cu and Leadframe alloys TAB Al wirebonds fracture in wirebonds Peddada Blish PQFP delamination bond failure D 3 Solder 37Pb 63Sn if T 30C A A QI NJ N N 2 0N ALON A NN 4852 OO N 2 Source Temperature Cycling and Thermal Shock Failure Rate Modeling R C Blish IEEE IRPS 1997 297 GENERAL MOTORS CORPORATION EDSON 2008 Appendix I Guidelines for Vibration Testing With A Reduced Sample Size Equation 6 Multiple Life Testing When Using A Reduced Sample Size l In I C normal sample size X n xin R reduced Test Hours est Hours reduced sample size This section is used to determine the sample size for the vibration tests if a success run plan is chosen instead of the preferred test to failure method explained in Appendix B The reduced sample size will increase the test duration and then one can increase the energy level of the test through higher Grms values to reduce the test time back to a desired duration For R 0 97 C 0 5 assumed Weibull slope of 2 5 and n 12 Two sets of six samples before and after temperature cycling and the standard test time of 8 hours along each of the 3 each axes 1 Hours Hours X dn l 5 97 ET 2 5 Hours 8 _In 5 1033 12x1n 97 Thus a reduction in sample size from 23 to 12 results in an increase in test time from 8 h
7. son 100 00 1000 00 Normalized Increase In Resistance B 6 2039 167 0619 p 0 9899 GENERAL MOTORS CORPORATION EDSON 2008 MECHANICAL TESTS Mechanical Shock and Vibration testing is essential for anything that is attached to a vehicle Mechanical shock 15 produced when the vehicle hits potholes in the road and vibration is the result of the general roughness of road surfaces Engine vibration is the result of the sinusoidal pulses of piston motion and the random vibration of valve train function The engine vibration is thousands of times damaging than the _ body chassis level of vibration The story here is dont mount something on the engine or transmission unless there is no other possible place to put it The vibration levels provided in this document for Body Chassis mounted devices are identical to those defined in the 5016750 3 specification This vibration level is the composite of vehicle data from Mercedes Benz BMW Opel Volkswagen and a large number of electronic manufacturers such as Bosch Hella and Visteon Over 750 data sets were used to establish the vibration profile and damage level The final vibration test provides an accelerated level of vibration that requires only 8 hours per axis This short duration test at an increased GRMS level was derived from the lower GRMS level that would occur for a much longer period of time
8. RR SUMI PI 210 Lou Circuit OE Current Busca elect DA 213 codsesdsqa suasasta t nbxue MU O DEMNM UM ME 214 PT ccc pass ec penne E E ENIM MUN MEUS II PR MORIENS 2r caudis etx I etn Exp UI PIU M MIN 216 UDNNECTIOR oos ME 216 VET EESE 217 Connector to Connector Engage 47 Locked Connector Disengage Force 4er iet teh arri re er HERREN CXER VERFU ae tns ere 217 Unlocked ee oe eee MM REM Urt Poe Vo RIEN TOT 217 ire TM NE 220 Why The Vibration Test Is Different Between Cars And Trucks 221 Why We Superimpose Thermal Cycling On Top Of Vibration 222 A Basic Understanding Of Plastic As It Relates To Temperature And Vibration n M A 222 EE OOE 227 Demonstrating Reliability For Robustness to Vibration eese 224 Vibration Sine Random Mounting Location Engine Transmission 221 Random Vibration Mounting Location Sprung Masses essere
9. L euueu 81 22 0 sued c uonasessi r pue uonaeadsu ensiA 8 58 2 guonsun uonen e q 3so0 d aey pue yeanbs euet 1 UJ AS wes e1nso 2 42ous Mechanical Fatique 00021009 uonmnen eA 3 344 aey pue 4eenbs 9 6 SHE aje duio 5 15 1 uonsassi pug uomnsedsu 51591 euonoun 3 Jo uonen eA3 L sued 132 GENERAL MOTORS CORPORATION EDSON 2008 aM JO spe pue 500 9 352 a 10 5006 pue 05 1 8 10 8051 pue sayapmg 91 ae 14 pue uonaedsuj jensiA 591 JUALWIE diu HONEA Ae Hamaur 4 p 5591 Jagen ABANS f 354d uua 8 s sanpo 553g 1 4 2 0 HOHO PEO f sud 19510 Puea hasoduiuadns asin
10. 48 49 CREEP CORROSION OF LEAD FREE CIRCUIT 8 2 50 ECONOMIC SELECTION OF LEAD FREE SOLDER csssccsssccsscccssccsscccssccsscccscccssccsscccsscescscsscessesessceess 51 TERMS amp CONSTRUCTION METHODS amp STATISTICS 51 ger ee eres ce 5 WAVE RE BIS HEIC IS BIS NT 5 IR REFLOW SOLDER PROCESS pd dte arai etd norat usd 52 TNR UR U 52 SEMICONDUCTOR COMPONENT CONSTRUCTION 0220000 0 000 53 CRACKED CERAMIC CHIP CAPACITORS AND BALL GRID 6 54 JOSISCITEOIBI CONDUCIVE TIENE CAU re ae ne ee er 54 CHP ON GLASS CONSTRUCTION 56 PININ PA TE 56 h EET AES AA EE 57 CHIP ON BOARD CONSTRUCTION cccccssccssccssccssccsscesscesccscesscesscesscevscesseessescesscesscesscesscesceesceass 58 COMPLIANT PIN CONSTRUCTION 58 SELECISBOCEDEBINO Lois paa aM EMI MI EM M E MM MEUM EM E UE 60 GENERAL MOTORS CORPORATION EDSON 2008
11. 11 amps 10 amps 3 amps rated load current Time 15 Min 30 Min 45 Min One amp change for each step with each step having a duration of 15 minutes all of the steps are not shown 14 amps 13 amps c 12 amps If failure occurs within the DUT upon making a one current of 3 amps sduiy 45 Min 15 Min 30 Min amp step then proceed to Phase Two see the explanation below Explanation Use an appropriate variable resistor to produce a controlled short in the DUT Identify the current when the fuse blows or the DUT develops an open If the DUT opens upon making a 1 amp step in current then proceed to Phase Two where a finer level of exploration occurs within the one amp step where failure occurred Phase Two does not need to be performed if the external fuse opens during a dwell during Phase One GENERAL MOTORS CORPORATION EDSON 2008 LOAD CIRCUIT OVER CURRENT BUSED ELECTRICAL CENTERS The Load Circuit Over Current Test for Bused Electrical Centers uses the simpler ISO 8820 test procedure This procedure is derived from the process used to test fuses Purpose The purpose of this test 15 to determine if the Electrical Center is able to meet specified requirements when subjected to maximum current allowable by the internal protection fuse Locations of Applicability All location but only but only for Bus
12. 9 428 222849 36 e412 502000 634588 772151 90 572 Benard s approximation MEDIAN RANKS SAMPLE SIZE 14 42830 11 702 18 647 25 508 32 575 39 544 46 515 53 485 602456 672425 742392 8142353 88 298 956169 15 4 516 10 940 17 432 23 939 304452 35 967 4342483 50 000 56 517 63 033 69 548 762061 82 568 89 060 955 484 in the hands of a severe use customer 16 e240 10 270 16 355 22 474 282589 34 705 406 823 46 4941 53 059 59 177 654295 71 411 776525 825 635 89 7230 95 760 17 32995 9 578 15 422 215178 26 2940 324704 38 e469 6 42234 50 000 55 766 6184531 676 296 73060 78 821 865 578 904322 962005 8e300 20e113 32 052 44 015 5529846 672948 79 887 910700 18 3 778 9151 145 4581 202024 252471 304 921 36 4371 41 4823 47 274 52 726 58 177 634 629 69 079 74 529 7T9 976 85 419 90 849 96 4222 T 4512 17 962 28 624 39 308 50 000 60 691 71 376 8220368 92 587 19 2 582 8 677 13 827 18 988 24 154 29 322 36 291 39 660 44 830 50 000 55 170 60 340 65 509 70 678 75 846 81 011 86 173 91 322 96 418 RELIABILITY EVALUATION POINT REP The number of cycles or hours of testing that is representative of one life GENERAL MOTORS CORPORATION EDSON 2008 10 6 697 16 226 25 857 255510 452169 542831 6420490 76 6142 83 774 93 303 20 32406 8 251 13 157 18 055 22 967 272886 22 795 3727190 4226258
13. Engine Compartment MN Developing One Delta T for Test Passenger Luggage Compartment GENERAL MOTORS CORPORATION EDSON 2008 When a Weibull Slope value must be Common Test Thermal Fatigue Strategy The GMW3172 committee has reviewed and discussed the merits and risks of the thermal fatigue equations defined in this document for leaded and lead free solder We agree globally that these equations express the best of what is currently known but we also agree that a more simplistic approach may benefit everyone On March 17 2006 we agreed globally to use the following simplified default values These values are the result of combining the equations with empirical experiences The following Simplified Number Of Leaded Or Lead Free Thermal Cycles shall be used and shall take precedence over all detailed leaded or lead free calculations It was also agreed that a ten minute dwell hot and ten minute dwell cold would be used for leaded and lead free solder No acceleration factor between Thermal Shock and PTC shall be used Seventy five percent of the total number of cycles should be executed using thermal shock and twenty five percent of the number of cycles shall be executed using PTC testing Additional thermal shock cycles can be used to offset an equal number of PTC when reduced test time is needed No fewer than 100 PTC can be used The detailed calculations in appendix E and F are provid
14. 1 00E 5 Fatigue 10000 Life 1000 Stress Beta 2 9 K 2 4567E 25 n 8 3048 1000 00 The S N Slope Of The Real Product Will Be Different Than What Is Shown In The Text Book S N curves shown in the back of text books assume a polished specimen without Li ioe ife any geometry characteristics that would concentrate the stress in one location this 4gs Text Book Value is seldom the case in real life loading type Different types of loading will decrease the slope of the S N curve as shown at the right C loading type Rougher surface finishes will decrease the slope of the S N curve as shown at the 9 right C surface finish 103 Geometric stress concentrations decrease the slope of the published S N curve as Change In S N Slope surface finish C notch factor NA Mean Stress Effect shown at the right notch factor Stress 90 Ultimate Mean Stress Effect can also reduce the life Life at 10 Life at 10 xC xC x Mean Stress Effect loading type surface finish x uh factor 23 GENERAL MOTORS CORPORATION EDSON 2008 Example Values For Factors Loading Type Values Loading Type Pure axial 9 Axial With Some Bending aan 31 _ Torsion Cast Iron Typical Notch Factor Values Notch Factor
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16. 96 STRESS STRENGTH NON INTERFERENCE 87 THE REAL BIG PICTURE 91 GMW3172 CODES AND 1 lt 92 aT EORI ES Tairas 92 E 93 BI MUI EA 95 FUNCTIONAL CLASSIFICATION CODES 96 CODE DESIGNATION BY LOCATION IN THE VEHICLE 97 CODE LETTER FOR ELECTRICAL 0 00000 ee ese tese ese he seen 101 CODE LETTER FOR MECHANICAL LOADS etr tassa pacer Exec Ek FE eme reU F xERY Re FUE eR 102 CODE LETTER FOR laces ecient ws cava 103 CODE LETTER FOR CLIMATIC LOADS nin 105 CODE LETTER FOR CHEMICAL LOADS AND UV 8 108 CODE LETTER FOR INTERNATIONAL PROTECTION BY 5 6 111 VALIDATION 124 E IR a ES ocn serie cod UNE URSI MIS I Ce GUI IUD DUO UPON B 124
17. will suffer contact DISENGAGE FORCE resistance increases GMW3191 Section 4 12 Purpose This test intends to induce degradation UNLOCKED CONNECTOR of contacts used in Bused Electrical DISENGAGE FORCE Centers using combination of humidity temperature and vibration GMW3191 Section 4 13 A Reliability level of Reliability 97 with a Confidence 50 is to be demonstrated on this test with the degradation data analyzed using Weibull Analysis This test may also be applied to other connection systems when fretting corrosion is consider to be high risk Locations of Applicability 215 GENERAL MOTORS CORPORATION EDSON 2008 This test primarily intended for Bused Electrical Centers that may be placed any where on the vehicle Procedure Monitoring Monitoring of resistance continuously during the test Occurs Operating Type The test shall be performed under operating type 3 2 A set of 6 samples shall to be used for the following test e Apply the Humid Heat Constant HHCO Test with a duration of 1 day as a pre treatment for the test samples Alternatively the humidity pre treatment be eliminated if the humidity can be provided during the vibration and thermal cycling test e The DUTs are to be operated and monitored during the test Subject the DUTs to random vibration according the Random Vibration Test appropriate for the mounting location of this device sprung m
18. 81 pue jensiA ajoujod ULIDJSAE AA abueua 91815 o poys aJUuEHTIBUL E pauuonayul sued 1291 9194 Aeq e Aupiung HH 68 468 3521 X dv yes x lt 5158 3 4 uonaafu 1 19 ho eT SOL 0007008 joys HOUS uous L Bel poys JASIA saur Ju ON puy See Aueipa 1 uneg x uoISOJ102 20 5 EUs Hen EA 3 94 JO sisAjeug PLOW jean qeu dun jeuoruauqg yeanbs q pue yg uonen ea3 enu 158 euonsun y 35 1 3 Jo pesoduoz uonen eA3 egu WEAS 9 SHEA ee Le sued 0 92 sued 91 2 01 Sed 9 amp Fsued 2 sued au 104 5159 a asau 1651 5355 4930 9851 59 pBe 2 134 GENERAL MOTORS CORPORATION EDSON 2008 ESTIMATED TOTAL TEST LEG DURATI
19. Default For Minor Shape Changes Small Holes In Plate 33 Surface Finish Values As forged 400 600 800 1000 1200 1400 1600 1800 Tensile ultimate strength S MPa Mean Stress Effects gt A mean stress produces a detrimental effect when tension opens micro cracks gt mean stress has a larger effect on high cycle fatigue than on low cycle fatigue gt See reference book Fatigue Testing and Analysis for calculations Notch Factor Effects In Welds Stress risers produced by grain boundaries or surface defects Butt weld Full penetration Cracks Fillet weld Actual stresses Mean stress Lack of fusion GENERAL MOTORS CORPORATION EDSON 2008 24 25 Generally The Notch Factor Has Greatest Influence On The Change In Life At Low Stress Testing Can Effectively Explore for the Existence of Un expected High Notch Factor Effects T Sharp Notches Infinite Fatigue Limit Reduce Fatigue Life Life 00 RM Hi Cycle te Fatigue Fatigue life Notch Factor he Effect Reduces ss 7 Life more Low 22 significantly at 10 Lower Stress Cycle Fatigue Stress Typical values for steel are shown of Notch Factor Effects RN Life cycles 105 Alternating stress amplitude psi x 10 3 gt
20. addition of mechanical compressive stresses will increase whisker formation Tin whiskers can form on products that are stored for a long time without use in normal warehouse environments Crystal Oscillator With Bright Tin Plated Nickel Underplated Kovar Leads FULL of Whiskers Pure Tin Region without Sn Pb Solder Coverage NO Whiskers Sn Pb Solder Covers Tin Plate Here How To Make Tin Whiskers Best Test for Tin Whisker Formation Qualitative only Thermal aging two weeks at 100 C Accelerated diffusion of materials like copper into the tin to produce compressive stress Humidity pre treat with moderate levels of humidity and temperature for 1 week 5096 to 8096 RH and 50 C Disrupts protective oxide layer and promotes whisker growth Thermal cycling crossing 13 C 5 to 40 Circular growth rings are formed every time 13 C is crossed Moderate thermal ramp rate of 10 to 15 degrees per minute for 50 to 300 thermal cycles to produce Tin Whiskers shock is not effective Compressive loading of joint will increase the rate of Tin Whisker Formation structural stress or vibration more quantitative and lengthy test method for tin whisker formation is provided by JEDEC Standard JESD22A121 GENERAL MOTORS CORPORATION EDSON 2008 CREEP CORROSION OF LEAD FREE CIRCUIT BOARDS ABSTRACT Creep Corrosion of Lead Free PCBs Randy Schueller Ph D Dell Inc Aust
21. 14048 28 poi wwe ters cece X 31 ss 33 ELECTRICAL CONNECTIONS AND 00000 35 Pree MM ME 35 Gold lo ie RR TR 35 The Tin Commandments Guidelines For The Use of Tin on Connector Contacts 36 Golden Rules Guidelines For The Use of Gold on Connector Contacts esses 2 85 5 26 tote 38 i 38 TEMPERATURE AGING OR DIFFUSION BASED DEGRADATION 39 DEGRADATION FROM PHOTOCHEMISTRY iscccssicterncraisecncsdcsatasieascsusieatabnasousdsucanscabunesadeeudiiatasianngeddacaass 40 PROBLEMS WITH RED PHOSPHORUS FLAME 0 6 66 ee eee 40 HUMIDITY INGRESS sed de bo eee SP Meses sp LE do UE 40 DENDRITIC GROWTH NETTE EENE PANN O EAE AENEASE EN 41 IB URS EE 42 2 MEM 47
22. SALT SPRAY Purpose To verify DUT functionality after exposure to Salt spray as experienced in coastal regions and Salted road splash This test is for products mounted outside of the passenger cabin or luggage storage area Locations of Applicability This test is applicable to any location on the exterior of the vehicle This includes under the hood within the plenum at the base of the windshield and within the doors wet area Test Procedure Monitoring Constant monitoring shall occur during the entire test to detect intermittent failures Operating Type The operating type shall be 3 2 during the time that the device is energized Mounting and Salt Spray Flow Mount the DUT centrally between the spray nozzles with appropriate load and voltage applied as described below The volume and force level of the salt spray should be designed to wash away any corrosion products that may form on the metal Adjust the flow of the salt spray through the spray nozzles so that the streams of fluid are strong enough to hit the opposite wall of the chamber with the sample support walls removed A typical chamber used to perform this test employs 12 nozzles operating at 15 psi and sprays a total of 30 gallons per minute These are approximate values and a significant degree of variation can be tolerated The nozzles typically spray a hollow cone pattern and spray all the way across the chamber 3 5 feet
23. mE As Agreed Upon CODE LETTER FOR CLIMATIC LOADS The Climate Code letter is very critical as it dictates many important aspects of environmental testing Consider the following High Temperature Test Underhood components will require 2000 hours high temperature testing passenger compartment luggage exterior areas will require 500 hours of high temperature testing Thermal Shock Cycles The correct number of thermal shock cycles required is defined in tables 26 and 27 The minimum number of thermal shock cycles shown below should be used when testing is not necessarily focused on the fatigue of solder joints The underlying message is that almost everything should experience some thermal shock even when solder joints are not being considered Remember you should always have at least 100 PTC cycles in addition to the GENERAL MOTORS CORPORATION EDSON 2008 104 105 thermal shock cycles Again please use table 26 and 27 for the correct number of PTC cycles gt Thermal shock my be eliminated and all thermal fatigue testing should occur using PTC testing in situations where large panels may warp with thermal shock and produce abnormal failure modes A large LCD screen would be one example of this situation Thermal shock would cause unequal expansion contraction of the product resulting in a momentary warping during thermal change and possibly produce abnormal seal failure This is something that may n
24. GENERAL MOTORS CORPORATION EDSON 2008 144 GMW3172 A D V TASK CHECKLIST DEVELOPMENT PROCEDURES Procedure This Program Development Tasks Functional And Dimensional Tests 89 Evaluation for basic functions at different temperatures and different voltages Dimensional 5 Evaluation for packaging size and potential for change as a result of warpage with high temperature annealing Jump Start 38 The 26 volt jump start is a critical design consideration Devices could be in the on or off position during a jump start Both on and off states should be tested Reverse Polarity BS Recent changes to require diodes across all of the motors in the vehicle will appear to present a problem in running this test This test must still be run with the diode removed Over Voltage The over voltage test should be run to ensure that the product is immune to a failing generator or a fast charge with a high power charger 145 GENERAL MOTORS CORPORATION EDSON 2008 This Program Procedure Short Circuit Tests MEME 15 Please read these tests carefully as not all tests need to be run on every product Intermittent Short Circuit Continuous Short Circuit Ground Interconnect to Battery Short to Battery Short to Ground EMC GM3097 This test should begin early in the program as it often takes several iterations to resolve problems testing should occur about the sam
25. Monitoring Monitoring is generally not possible during thermal shock because of the motion of the parts and the resulting fatigue of attaching wires Operating Type The test shall be performed under operating type 1 1 Use test methods according ISO 16750 4 Rapid Change of Temperature With Specified Transition Duration The temperature cycle testing shall be performed according to IEC 60068 2 14 Na The appropriate dwell time at each temperature needs to be proven by measurements The dwell time at high or low temperature should be 10 min The Dwell Timer shall begin when the inside of the product reaches Tmax or higher minus 39C or Tmin or lower plus 39C The minimum number of cycles is given in Table 5 The appropriate number of cycles that must be run to demonstrate the required reliability requirement can be derived from the equations in Appendix E and F GENERAL MOTORS CORPORATION EDSON 2008 246 247 Upon agreement with General Motors this test can be performed without a case or with a modified case to increase the rate of temperature change This test is generally performed without the product being electrically energized during testing The temperature range used in the thermal Shock test should be adjusted for devices that generate significant internal heat to compensate for the lost temperature change with a non energized device For example ifa device is to be tested from 40 t
26. Our Vi U ned State nts 95 From Passi V As A Liquid Prev i o Sing Through Por State That Small An Opening a ic Water Molecule ms Water Vapor State Pass 7 Water Molecule Water MoleculA 3 4 10 is Size Opening 3 4X10 gt _34 10 cm Through Th gt 15 2 103 cm Van der Weale Forces Hold Molecules Together Temperature increases the vapor pressure of the water vapor to accelerate it s permeation through coatings encapsulations DENDRITIC GROWTH Dendritic growth is an electrolytic process in which the metal from the anode region migrates to the cathodic region This phenomenon is accelerated with the presence of moisture and ionic contamination on the surface of the circuit board between two circuit traces with differing voltage potentials The dendrite grows until a short circuit is formed upon which the dendrite vaporizes leaving a residual line between the two circuit traces that looks like a pencil mark GENERAL MOTORS CORPORATION EDSON 2008 40 41 Electromigration And Dendritic Growth n x 4 n Dew condensation droplets d Water film area Dendrite Moisture even the form of humidity combines with ionic contamination on a circuit board to form a solution that will conduct electric current and support copper migration The migrating copper forms parasitic conductors known as dendrites Dendrites grow between traces and ca
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28. 263 Table 33 Seal Evaluation Requirements Fluid 5 DUT Temperature T max Above The Fluid Depth 76 5 0 mm Figure 48 Seal Evaluation Test Setup Recording Device Power Supply Test Fluid t UAM Level Ground Case If Applicable Submerged Ground Connection If Applicable Criteria Functional Status shall be class A during and after the test The DUT shall be opened inspected for signs of leakage at the end of the test An ultra violet light source should be used to detect the potential ingress of saline solution containing ultra violet dye No leakage is permitted SUGAR WATER FUNCTION IMPAIRMENT The Sugar Water Function Impairment Test evaluates the sensitivity of the product to the effects of condensing sugar water or the crystal precipitation of sugar water This residue can impair the function of moving mechanisms or switches This test in primarily intended for products located in the interior of the vehicle Purpose The purpose of this test 15 to determine if the DUT is able to meet specification requirements when exposed to dried fluids that once contained dissolved sugar Locations of Applicability This test is applicable to areas that will become contaminated by sugar sweetened beverages and produce erratic motion in sliding systems Procedure Monitoring No monitoring of the device occurs during the test Mo
29. Above or below or within or without And that s the reason beyond a doubt That a chaise breaks down but doesn t wear out But the Deacon swore as deacons do With an I dew vum or an I tell yeou He would build one shay to beat the taown the keounty n all the kentry It should be so built that it couldn break daown Fer said the Deacon 15 mighty plain Thut the weakes place mus stan the strain n the way t fix it uz I maintain is only jest T make that place uz strong uz the rest So the Deacon inquired of the village folk Where he could find the strongest oak That couldn t be split nor bent nor broke That was for spokes and floor and sills GENERAL He sent for lancewood to make the thills The crossbars were ash from the the straightest trees The pannels of whitewood that cuts like cheese But lasts like iron for things like these The hubs of logs from the Settler s ellum Last of its timber they couldn t sell em Never no axe had seen their chips And the wedges flew from between their lips Their blunt ends frizzled like celery tips Step and prop iron bolt and screw Spring tire axle and linchpin too Steel of the finest bright and blue Throughbrace bison skin thick and wide Boot top dasher from tough old hide Found in the pit when the tanner died That was the way he put her through T here said the Deacon naow she ll dew D
30. IPC Lead Free Conference Proceedings San Jose 2003Corp TIN PEST Tin undergoes allotropic transformation of beta tin body centered tetragonal with a silvery appearance into alpha tin diamond cubic with a gray appearance at temperatures below 286 K 13 C or 55 F This transformation results in a phenomenon known as tin pest The change in transformation is accompanied by an increase in tin volume by 26 and a significant increase in material brittleness of the tin The following shows prolonged exposure of a tin 95 copper 5 alloy to low temperature 18 C over a 1 8 year period Forty percent of the specimen surface was transformed into grey tin alpha tin after 1 5 years producing a gray wart like appearance on the surface of the specimen Degradation accelerated with 70 of the surface becoming transformed into gray tin after 1 8 years An incubation period appears necessary as only a superficial film of gray tin was seen after 1 year The transformation process results in the crumbling of the tin as expansion is combined with embrittlement A tin lead sample that was exposed to the same conditions exhibited no degradation what so ever These facts indicate that tin pest has the potential for becoming a major hazard in applications where tin based lead free solder is exposed to low temperatures for prolonged periods of time The test time needed to see significant degradation exceeds available time during product de
31. Operating Type The operating type shall be 1 2 during the heating portion of the test The operating type shall be 3 2 during the water submerging portion of the test Place the DUT chamber at Tmax in a temperature for at least 30 minutes or long enough to ensure that Tmax has been reached within the device The device should not be electrically connected or energized during the high temperature soak Remove the DUT Connect the power and monitoring equipment and immediately immerse the device into the test solution The test solution should be a 5 saline solution doped with water soluble ultra violet dye Connect the power and monitoring equipment prior to each submergence period but keep the device un powered for the first 20 minutes of the submergence period The device should be energized during the last 10 minutes of the submergence period The DUT shall remain submerged for a total of 30 min Repeat this procedure and function the DUT until a total of 15 submerging cycles have occurred Check all functions and parametric values during and at the end of the test Special Note The ground wire is to be placed under water along with the DUT during the test for all sealed controllers when the ground wire will be located low on the vehicle Extra Special Note Any device that is expected to keep out water should receive this test as an evaluation activity GENERAL MOTORS CORPORATION EDSON 2008 262
32. 179 Glowna IRIEFDORBESET SORE TO DUNOD M SU 179 jes ge eke ea om Carpon bi W OOT 180 Ground Path Inductance 180 Device State Change orn eae 181 Processor Supervisor Perjormance ON Eia ans 192 PUE TUS nut e EHE IN IEIUNII a ve M MEME 182 MECHANICAL TESTS IN 183 Highly Accelerated Life Test 183 Sr CONES E131 30 Der Ce TOUSE RON crm 184 OE TO EIE ere E ee 186 CGS TEE ORG MM MM MM ME MEME eee ery eee eee ee 188 Mechanical Shock Pothole And Colisi n 188 Doon S NN OT EN E E 190 TEMPERATURE TESTS IN DEVELOPMENT 191 GENERAL MOTORS CORPORATION EDSON 2008 Thermal Pe OO 191 c 191 Infrared Imaging Method
33. 2008 168 169 Temperature Voltage Room 1 Nominal Temperature Maximum No Voltage Applied Repaint 1 Hr in high Temperature durability test if required Maximum Maximum Temperature Nominal 3 Temperature Voltage Functional amp Parametric The Functional Parametric Test may be performed at only five points with the approval of GM Engineering 1 Tmin Vmin 2 Tmin Vmax 3 Troom Vnom 4 Tmax Vmin 5 Tmax Vmax FUNCTIONAL CHECKS AND CONTINUOUS MONITORING Products can demonstrate intermittent behavior during certain combinations of stresses and at different stress levels We do not have the prior knowledge to know what combination of stress levels will reveal problem Therefore the continuous monitoring process is necessary to detect intermittent problems that may occur at certain times ina test This is required during the vibration test PTC test high temperature test constant humidity test and cyclic humidity test Continuous monitoring should occur as frequently as is reasonable however it does not always need to be truly continuous or every millisecond For example during the PTC test which may last for many days it would not unreasonable to monitor each circuit every several seconds The Functional Check Shall Example with Operating Type 3 1 GENERAL MOTORS CORPORATION EDSON 2008
34. 8 seal evaluation 10 240 Sequence of test steps 1 The first 2 hours of the total test duration should be run at a reduced fog level 0 25 0 5 milliliters per hour on 80 cm with the device energized and operating 3 2 The salt fog is to be a 5 solution with pH of 65 7 2 per IEC60068 2 52kb This pre test is a measure of the degradation of function resulting from a salt laden air environment with expectations of proper function of the device 2 De energize the device 3 Soak in a humid environment for 22 hours per the IEC60068 2 52kb specification 4 The remainder of the cycles two hour salt fog followed by 22 hours of humidity are to be run at the normal level of fog per IEC60068 2 52kb Criteria Functional Status shall be class A The DUT will be evaluated for electrical and mechanical function after cleaning at the end of the test The DUT will also be evaluated for critical loss of parent metal that may lead to loss of internal 3 and 4k 6 144 or Luggage or external connections 255 GENERAL MOTORS CORPORATION EDSON 2008 Water drop Corrosion Of Steel Under A Water Droplet Figure 46 North America Corrosion Map NORTH AMERICAN VEHICLE CORROSION ENVIRONMENT NEGLIGIBLE 8 MILD B L PXTACMELY SEVERE GENERAL MOTORS CORPORATION EDSON 2008 256 25 Figure 47 Salt Spray Corrosion
35. Check functionality while the DUTs are exposed to the test environment The DUT shall be powered up from a shut down power mode to a normal Operation power mode All DUT inputs outputs including on vehicle communications shall be cycled and monitored for proper functional operation The functional check shall be time limited to prevent self heating of the device while being exposed to specific test environments The input output cycling and monitoring shall be automatic and shall not require human intervention Or observation at any time during the test to detect and record a nonconformance Test Criteria supplier is responsible for developing a detailed test criteria list which will define the following e How and which functional operations will be verified and or continuously monitored e The list of key parameters to be measured and recorded e The list of build variation related parameters to be statistically analyzed e list of degradation related parameters to be statistically analyzed e The nominal and range limit values for the measured parameters to ensure performance in accordance with the CTS e The procedures must be submitted for approval to the GM Validation Engineer After approval the document shall be under change control and any future changes must be submitted for approval to the GM Validation Engineer Continuous Monitoring Continuous Monitoring verifies that t
36. I ambient T Ta level sea level ambient x Multiplier ltitude You must know the temperature of the DUT while operating at full power at sea level The multiplier generally 1 33 is used to gt the temperature differential for high altitude operation Tambien is assumed to be the temperature of the surrounding product environment You must solve for Tatitude using the above equation Criteria The process requires documented evidence of adequate design margin based on the operating specifications for the component generating heat and other sensitive components nearby THERMAL FATIGUE ANALYSIS The Thermal Fatigue Analysis can be performed using the simple equations the book Vibration Analysis For Electronic Equipment by David Steinberg reference 1 or with Finite Element Analysis Thermal fatigue results from the repetitive stress generated by cyclic temperature change when materials with different expansion contraction rates CTE are attached to each other with a non compliant system The solder used attach components to circuit boards becomes the focal point for the stress generated by the different expansion rates of the component and the circuit board Leaded components have a built in compliant mechanisms in the lead itself but surface mounted components have no leads and thus all of the stress is concentrate in the solder joint Purpose The differential ex
37. M HC y NE Unt 2 ah ea i v s Y i NVA N TO we x NH N x t N LP Ma 4 a 7 2 Pm P 4 s 2 E base 1 t mo S Ye 1 y j ai i TAL THE GMW3172 USERS GUIDE THE ELECTRICAL VALIDATION ENGINEERS HANDBOOK SERIES ELECTRICAL COMPONENT TESTING Wait I still have more to learn w AfA LO A Day In A Past Life By Farry Edson Revision 19 2 13 08 GENERAL MOTORS CORPORATION EDSON 2008 Table of Contents HOW USE THIS DOCUMENT vce scvcsesccsdscssccdscccsscctsaccerecesadecsdesessecestesascsvocsncdceses 10 THE QUICKSTART YER UPS 12 FREQUENTLY ASKED QUESTIONS EXE SET 13 ABBREVIATIONS AND SYMBOLS 5 2 testo eeeeaseubso opo e 17 TECHNICAL KNOWLEDGE lt 20 THE TWO BASIC GROUPINGS OF FAILURE 8 8 hene esee ne sees sese sees 20 BASIC METAL FATIGUE 22 CRITERIA FOR FATIGUE AND STRENGTH
38. The component passes standardized component testing for resistance to the ingress of humidity and demonstrates adequate robustness for exposure to temperature during processing No prior warranty issues are know to have occurred as a result of changing from leaded pre tinning to lead free pre tinning of components using the planned manufacturing process If such problems have occurred in the past then explanation of such problems must be provided along with explanation of corrective action as part of the Validation activity Suggested Validation Run a wetting balance test Meniscograph test on the new component to verify that the lead free part meets the minimum response in time and wetting force that the supplier has determined is required for their soldering process Submit a copy of the Reflow Wave and or Selective Solder Machine temperature profile with written verification that the profile meets the solder and component manufacturer s thermal requirements An example is shown below Reflow Profile for Indalloy 241 95 55n 3 8Ag 0 Cu 300 150 Temperature 100 i Liquidus 1 2 3 1 5 Time Min GENERAL MOTORS CORPORATION EDSON 2008 72 73 LEAD FREE SOLDER REQUIREMENT FOR NEW PRODUCTS IN 2009 We have reached a major milestone of change in the world of electronics We will now be switching from a lead based solder to a lead free solder The wording that has been placed
39. The forces required to repetitively make the assembly must be low enough to prevent human injury The following forces have been established as upper limits by experts in the world of human factors for the following methods of assembly The requirements are e Allowable installation forces are not to exceed e 27 Newtons 6 pounds per hand e 11 Newtons 2 5 pounds for a thumb e 9 Newtons 2 pounds for a single finger e expect that my assembly will be made using one hand two hands finger etc My maximum assembly force requirement is Ibs 3 Your assembly should not be allowed to move in any unwanted direction and this includes rotation You must document how you are controlling the motion of three axes of translation and three axes of rotation Show how you have constrained three translations and three rotations Also show that you have not double constrained any rotation or translation Multiple constraints in any one direction can create interference problems 4 Establish whether this assembly will be designed for disassembly without damage When disassembly is necessary the snapfit geometries must allow for disassembly either through an applied force or by providing an access opening for a release tool When the assembly is expected to come apart by applying force then the ramp angle that is used for retention must not exceed the critical angle The critical angle is a value less than 90 degrees but will act
40. 098 2 6 amp 2 GENERAL MOTORS CORPORATION EDSON 2008 304 Appendix Plastic Snapfit Design Worksheet 1 The primary objective of the design should be to develop an interlocking integral attachment using engaging lugs in the direction of primary forces The attachment strategy should utilize the engagement of interlocking lugs functioning in the primary direction of usage force Plastic snapfit features Should operate perpendicular to the primary direction of usage force to minimize stress on snapfit structure Example a sphere is made in two halves The primary direction of force during use results in pulling the two halves apart One could plan to snap the two halves together directly but that would place primary forces on the snapfit features The optimum strategy involves engaging the two halves through interlocking lugs with a Small twisting motion Radial snapfits would be designed to keep the lugs engaged The snapfits must only resist an unscrewing motion the least likely direction of usage force e When an interlocking lug approach is not feasible because of motion constraints a hook and snapfit should be considered The hook is a very strong and robust retention feature that is also easy to mold The hook acts as a retention feature a locator and controls the motion to better align the snapfit The single snapfit completes the assembly e When a hook and snapfit is not feasible because of moti
41. 128 FIGURE 12 THE PRODUCT DEVELOPMENT AND VALIDATION TIMELINE cscceeccsscssccsccsscescesseeces 129 FIGURE 13 UNIVERSAL ELECTRONIC DEVICE DURABILITY TEST FLOW FOR LEADED SOLDER 133 FIGURE 14 UNIVERSAL ELECTRONIC DEVICE DURABILITY TEST FLOW FOR LEAD FREE SOLDER 134 FIGURE 15 SMART SWITCH TEST FLOW FOR LEADED SOLDER 20 eene nennen 135 FIGURE 16 SMART SWITCH TEST FLOW FOR LEAD FREE 5 nnne 136 FIGURE 17 HALT CHAMBER BY THERMOTRON ji csscccseccssscosscessceccsecssoccsseccosceovecssseerssecesecssncvessecessesseense 184 FIGURE 18 FOOT LOAD APPLIED METHOD TO TOP OF DEVICE HOUSING nmn 185 FIGURE 19 FOOT LOAD METHOD B CONNECTOR TEST 187 FIGURE 20 100 G MECHANICAL SHOCK TEST DEVICE 190 FIGURE 21 HAST CHAMBER WITH DOOR OPEN cicssccssecsssccssctesosttoscssverovecsssessaecstoucevacdescseveuevseecseeosbenes 194 FIGURE 22 HAST CHAMBER VIEW OF THE RACKS THAT HOLD THE 195 FIGURE 23 HAST CHAMBER VIEW OF INTERNAL ELECTRICAL JUNCTION BLOCK 195 FIGURE 24 SIMPLE PARASITIC CURRENT 6 nente eas 197 GENERAL MOTORS CORPORATION EDSON 2008 FIGURE 25 PARASITIC CURRENT EVALUATION GOOD AND BAD BEHAVIOR WITH DECREASING ee eee ean AT dM du E E 199
42. 472542 52 458 57 374 62 289 67 205 722 119 772033 81 945 8648523 91 749 96 594 SUDDEN DEATH TESTING Testing subgroups of a large number of samples to identify the first failure from each subgroup the un failed parts are discarded The Weibull plot of the first failures of each subgroup is used to predict the total population This method is useful for small and inexpensive parts such as relays light bulbs and mechanical springs sudden Death Life Testing Probability Weibull Identify the 50 point me Weibull square on the Weibull plot Line From of the 7 failures and extenda Plot of ud line downward until you Failures reach the first median rank value oval based on the size of the subgroup i Example Our subgroup PO sample size is 10 thus gt HN the first median rank 6 79 re This Line value 10 is 6 796 idi F Daned Draw a line through this From point oval parallel to the Other Line original Weibull plot line di This new line is the Weibull Applications B 3 5000 n 299 8073 plot line as if all 70 parts were tested to failure Figure 7 Sudden Death Testing Explained GENERAL MOTORS CORPORATION EDSON 2008 68 CALIBRATED ACCELERATED LIFE TESTING CALT CALT is a method of testing a
43. Density Adding up the Area Under the Curve Using The Weibull CDF Small Sample Size Note the increased variation about the line with a smaller sample Waloddi Weibull 9 Weibull 1887 1979 Sample size of 6 from a Highest Median Rank Data 1 distribution with a Slope 2 5 Characteristic Life 100 Sample Size 6 Order Median Rank A Small m 8 10995 Sample Size i ProducesA gt 68 26 4 Less Easily 5 Lowest Median i Identified Rank 85 42 1 Straight Line 5 i 10 00 The Weibull Slope is 94 57 9 the rise over run of 1 73 69 x oe the best fit line ae M 220 89 1 1 64 n 111 56 0 96 T 1 00 a ae T 10 00 100 00 1000 00 1 6400 n 111 5600 Hours On Test Until Failure WEIBULL SLOPE The Weibull distribution can take on many different shapes and the Weibull Slope parameter is the indicator of that shape The Weibull Slope is the actual slope of the cumulative distribution line as shown above Small slope numbers indicate a distribution that is spread out Large slope numbers 65 GENERAL MOTORS CORPORATION EDSON 2008 indicate a distribution that is
44. Eval Eval Detection Vibration with Thermal Initial Initial Initial Temp Temp Temp Volts Volts Para Eval Para Eval Para Eval Moisture Suscepti Cyclic Or IP Code Constant Testing Humidity Dust Detection Vibration with Thermal IP Code Testing Water Post Temp Volts Para Eval 13 GENERAL MOTORS CORPORATION EDSON 2008 Room Temp Unom Volts Para Eval Fretting Corrosion ISO 8820 Over Current High Mounted Exterior Sealed Module Leaded Table 10 Test loo Test Leg Test Test Test Leg 0 2 2 Leg 3 Leg 4 Leg 5 Initial Temp Volts Para 500 Hr High Temp Initial Temp Voltst Para Initial Initial Initial Temp Temp Temp Volts Para Volts Volts Para Eval Para Eval Initial Temp Volts Para Eval Para Eval 100 G 20 Moisture Mech i To Suscepti Humidity 1 Shock 40 bilit Optional 40 G Mech Shock Closure Cyclic Or Constant Humidity Vibration Detection With Vibration Thermal with Thermal Post Temp Temp Volts Para Volts Eval Para Eval Volts Volts Para Para Eval Eval LEAD FREE SOLDER IP Code Testing Dust IP Code Testing Water Post Temp Volts Para Eval Fretting Corrosion ISO 8820 Over Current Interior Module Lead Free Table 11a Table 11 a b c d e Lead Free Solder Test Duration In Days By Test Leg Test pes Test Leg Test Test Test Test Leg O 1 2 Leg 3 Leg 4 Le
45. FIGURE 26 VOLTAGE DROP TEST sisiesiccenssccseavensd5eivsunesesescsaseanedicsbawouedducdaupsstvesesddieebeadsbasewsiouistascoeseonss 201 FIGURE 27 BATTERY VOLTAGE DROPOUT PROFILE 2 0000 0 0000000000 202 FIGURE 28 LOAD CIRCUIT OVER CURRENT TEST PROCEDURE FOR 212 FIGURE 29 CROSS SECTION OF AN ELECTRO DYNAMIC SHAKER 0000 224 FIGURE SOURCES OF ENGINE VIBRATION EENE 227 FIGURE 31 SINUSOIDAL VIBRATION FOR ENGINE OR 6 56 0 00 00 228 FIGURE 32 RANDOM VIBRATION PROFILE FOR ENGINE MOUNTED DEVICES ccrte 228 FIGURE 33 RANDOM VIBRATION PROFILE FOR SPRUNG 55 5 230 FIGURE 34 RANDOM VIBRATION PROFILE UNSPRUNG 55 2 00 0 0 0 6000 60 nete teens 231 FIGURE 35 THERMAL CYCLE APPLIED DURING 2 44 0000 0000 232 FIGURE 36 THERMAL CHAMBER OVER HYDRAULIC SHAKER eene hehehe rentrer een 253 FIGURE 37 SLIP TABLE TYPE SHAKER WITH THERMAL 233 FIGURE 38 EXTRACT FROM ISO 16750 3 SHOWING HOW TO RUN THE FREE FALL DROP TEST 238 FIGURE 39 LOW TEMPERATURE W AKEUP TEST 2 0 6000000 240 FIGURE 40 THERMAL CYCLE PROFILES IN 6000000 000000 245 FIGURE
46. That s post heat A product mounted high in the rear of the engine compartment should use a code letter H Things mounted on the engine would use a code letter I The product will actually experience these temperatures in the vehicle Tmax pps affectively covers high temperature storage and one should look for warpage in plastic as stresses are relieved during this first hour of Testing Table 4 Code Letter for Temperature Used In Thermal Shock PTC and High Temperature Durability Testing Code T min T max PH T max RPS Letter T max Post Heat C Tmax Re Paint amp Storage C Use for the first hour of the high temperature test if greater than Underhood Post Heat use Tmax Accounts for high for the first 5 of total temperature storage and paint high temperature test booth exposure Used In High Temperature Durability Testing Product is Powered Product is not Powered 103 GENERAL MOTORS CORPORATION EDSON 2008 Used In Thermal Shock PTC and High Temperature Durability Testing Used In High Temperature Durability Testing Product is Powered Product is not Powered Code T min T max PH T max RPS Letter T max Post Heat C Tmax Re Paint amp Storage C Use for the first hour of the high temperature test if greater than Underhood Post Heat use Tmax Accounts for high for the first 5 of total temperature storage and paint high temperature test booth exposure 40
47. Who else uses GMW3172 besides me e This is a global document and is used by GM in all of the countries where GM has a presence Mexico Germany Sweden Brazil Australia and East Asia are using this document right along with you 4 Do Ford Chrysler and Toyota use a similar document e A similar but not identical set of documents exist in each of these other organizations I have reviewed and studied the documents from Chrysler Toyota and Volkswagen as a benchmarking effort to ensure that GM requirements are not lacking in any particular area Conclusion GMW3172 is exceptionally comprehensive without being excessive Our suppliers and competition recognize the value of the comprehensiveness of GMW3172 Companies like UPS have 13 GENERAL MOTORS CORPORATION EDSON 2008 chosen to use GMW3172 for validation of vehicle aftermarket products A common question is often posed The supplier is moving his circuit board assembly operation from Ajigistan to Bajigistan What tests should be rerun This is a case where one needs to return to the basic concepts behind the physics of failure see the section on Failure Mechanisms When product manufacturing is simply relocated there is a concern for assembly quality and ionic contamination When design changes are made the concern increases Please read the section entitled Evaluation of Engineering Changes After production How do I know wheat vibration requirement to us
48. cause of the all axes effect 2 The 100 G test simulates the effect of a significant vehicle impact that does not result in the vehicle being totaled Those portions of the vehicle that were not directly affected by the collision would experience an approximate a 100 G half sine pulse Electronic devices that existed outside of the impact area should not need replacing as a result of the impact force The concept of 100 Gs may seem excessive however dropping your calculator onto a hardwood floor from waist height will result in Gs The criteria for the 100 G test is more lenient that for other mechanical shock tests Some bending acceptable however nothing that would represent a hazard to the vehicle owner is allowed 3 The 40 G door hatch slam test is simulated on an Electro Dynamic Shaker and represents the level that would be experienced by the inner panel structure of the closure system the door or the hatch Mechanical Shock Pothole And Collision Purpose The purpose of this test 15 to determine if the DUT is able to meet specification requirements when Subjected to the mechanical stresses like potholes minor repairable collisions and door closures Locations of Applicability Test severity is different for different areas of the vehicle Procedure Monitoring Proper function is not expected during application of mechanical shock GENERAL MOTORS CORPORATION
49. jen 125 aco vase EM MEI MED E 125 DE IGN REVIEWS OO 126 THE TEST FLOWS 130 UNIVERSAL ELECTRONIC DEVICE DURABILITY TEST 0 132 OMAPT SVIN H ee EA ee 152 ESTIMATED TEST DURATIONS 137 GENERAL MOTORS CORPORATION EDSON 2008 eee RE 137 140 GMY 144 GMW3172 A D V Task Checklist DEVELOPMENT Procedures ecce 147 GMW3172 A D V Task Checklist DESIGN VALIDATION 3l GMW3172 A D V Task Checklist PRODUCT VALIDATION 157 ANALYS ACTH eiit i EE NS EEEN S 160 EDECIRICAD AN AUN SIS eanna E NE A 160 Nominal And Worst Case Performance Analysis sc isiacccassasinedseeexsaderdadsrdiasacenospaaieedbeaawsaanereraaes 160 OO E FS A N I E E E O E EE E 161 Mu ODE T EE E EAE OE EEE E EA E AE E 161 MECHANICAL ANALYSIS 162 Circuit Board or Other Critical Element Resonant Frequenc
50. lost during the corrosion test for a sealed module the follow up seal evaluation test will effectively detect the loss of seal integrity Criteria The functional status during and after the test shall be class A The acceptance criteria for corrosion is not limited to conditions as observed at the end of the Salt Spray Test Corrosion can start and continue at different times of the test sequence thus the corrosion acceptance criteria applies to the entire sequence Failure of any Functional Parametric Test item during or at the end of the test is not acceptable Structural corrosion damage that reduces structural physical properties of a material by 25 or more at the corrosion site is not acceptable Structural corrosion damage is defined corrosion related material loss or degradation that weakens the physical properties related to the structural integrity and strength of the device or assembly or packaging These properties include but are not limited to yield strength hardness pierce strength mass buckling or flex resistance etc Degradation of cosmetic appearance over the exterior of the device or bracket is not allowed on surfaces exposed to vehicle occupants Corrosion that does not penetrate deeper than 5 of the thickness or covers more than 10 of the surface area is acceptable in areas not exposed to the customer GENERAL MOTORS CORPORATION EDSON 2008 258 259 Table 32
51. modifications to reduce the cantilever thickness should be considered to assist in controlling the strain in the cantilever Calculate the width of the cantilever to develop the forces desired Altering the width generally does not affect the strain in the cantilever but does affect the forces Increasing the width will increase the force proportionally and vice versa Use thickness tapering and width tapering to make your design more efficient See the tapering section in the references for the suggested ratio of the taper usually 2 to 1 Tapering can be helpful when attempting to obtain the greatest degree of flexure from a short cantilever The forces that the flexing cantilever will exert depend on the plastic material being used The Secant Modulus is a characteristic of the plastic and is used to determine how much force a particular type of plastic will exert in a flexing situation Secant Modulus values for various plastics can be found in the reference material The equations necessary to perform the following are available reference 11 Design Of Integral Attachments And Snapfit Features In Plastic Commercial software is also available to improve the accuracy and speed of this analytical process GENERAL MOTORS CORPORATION EDSON 2008 11 12 13 e Show the math that predicts the forces to assemble and disassemble e Show the math that allows for disassembly if disassembly is a requirement e Sh
52. plastic parts degraded conformal coatings solder masks or seals circuit board delaminations lifted circuit board traces signs of dendritic growth across circuit board traces corrosion such as black silver sulfide spots chip components organic growths or environmental residues due to dust salt moisture etc 6 Other Abnormal or Unexpected Conditions Changes In Appearance Or Smell 7 The Formation Of Tin Whiskers When Lead Free Solder Is Used The test plan provided in this GENERAL MOTORS CORPORATION EDSON 2008 document will effectively precipitate the formation of tin whiskers in lead free solder if that possibility exists during normal life cycle manufacturing A close examination of the circuit boards with a magnifying device Should occur following PTC testing prior the vibration The appearance of tin whiskers during the test flow process will indicate the probability of similar tin whisker formations occurring in the field The formation of tin whiskers poses a risk to close pitched components and may result short circuiting products that are being used or stored in Service Parts Operation 8 Absence of Dendritic Growth The Circuit Board Components Must Be Free Of Dendritic Growth 9 Solder joints should be sectioned to ensure that the formation of voids is kept to an acceptable minimum level A summary of each DUT s condition shall be documented and
53. stress 10 20 30 4 Small changes in geometry will shift the S N curve to the left Very significant changes in geometry will also change the au slope x p GENERAL MOTORS CORPORATION EDSON 2008 Notch Factor Effects Continued Fatigue strength N mm 2 Note Higher strength materials are more highly affected by notch effects Stress range at 10 cycles Plain machined N mm 2 3 specimens SM Fi ei __ 300 200 A 100 O 200 400 600 800 1000 1200 Ultimate tensile strength N mm at 10 600 400 Plain material 200 200 400 600 800 Ultimate strength N mm 2 Note The reduction in life is most pronounced at the high cycle end of high cycle fatigue Corrosion Fatigue Interaction Corrosion produces stress risers that decrease the fatigue life of stressed metals Alternating stress amplitude 3 psi x 10 100 Unnotched air Alternating stress 5 a 80 5 60 Corrosion 103 104 105 106 10 10 Applied cycles to failure N i Unnotched water 4 10 10 10 10 Cycles to failure GENERAL MOTORS CORPORATION EDSON 2008 26 The S N Phenomenon Also Applies To Plastic Cycoloy PC ABS Resin Tensile Fatigue Life vs Stress 24 Deg Eta 1 00E 7 F 19 S 0 IPL Weib 80 Degrees C N
54. task check list in appendix M Added explanation for the 1 hour vibration with thermal test Corrected drawing of thermal shock graph Explanation given for Tmax re paint used for high temperature storage Vibration test durations clarified Waveform analysis returned to checklist Notes of deviation to the standard procedures for future programs to conform to the Canadian CAN ULC 338 98 specification for Theft Deterrent Electronic Immobilization devices Included missing Fault Injection Testing requirement in ADV Checklist 100 mechanical shock tester picture added Expanded explanation about wetting times Added table for water spray test conditions and durations Clarified time at zero volts for battery voltage dropout test Correction for reference to table 26 Expanded use of Seal Evaluation Test Cracked ceramic capacitor note Temperature conversion table added GENERAL MOTORS CORPORATION EDSON 2008 270 Rev 15 Improved criteria for water penetration during 2007 Enclosure Protection Testing Additional Open Circuit Testing as a development test Rev 16 Oct Changes in Constant Humidity test temperature and 2007 duration Moisture Susceptibility introduced to replace the Frost and Dew Test Limited publication for Canada Rev 17 Nov Corrections to table five and expanded explanation of 2007 the Fretting Corrosion Test Operating type changed for International Protection Dust and Water Testing
55. terminals and terminal connections such that a high resistance condition is produced Corrode exposed traces leads resulting in loss of connection The Sa t Mist Test is intended for interior located devices It is very important that the device on test be energized as specified below if prone to salt water dripping It is also important for the proper connector to the DUT be used and not disturbed during the duration of the test The DUT does not need to be positioned in the in car position during the salt mist test The salt mist test is an accelerated test for an interior device and will produce condensation at a level that will not occur in the field The DUT should be positioned in the salt mist chamber so that condensate will not collect in the DUT or upon the circuit board The device on test should be washed clean following the corrosion test to permit close examination for material loss or degradation of critical surfaces The device must function properly at the end of the test following cleaning The Sa t Spray Test is designed for areas outside the passenger trunk area where a washing action of salt water is possible The washing action increases the corrosion rate by removing the oxidation by products increasing the exposure of bare metal The 70 degree portion of the Sa t Spray Test can be reduced to 50 degrees if the chamber system is not capable of reaching 70 degrees European labs often do not h
56. than the reliability that was demonstrated on test GENERAL MOTORS CORPORATION EDSON 2008 Table 36 Test to Field Correlation Values est is equivalent to a severe user under field conditions Test Reliability at One Test Life gor CHE Ratio Severe So a CVR Reliability 1 1 TRE Slope on Test Beta v 10 soe pated Bay on Test Beta Slopes if p B ns B B 0 99 09 0 57314 0 95855 0 93861 0 88087 0 93461 0 87197 0 78735 0 59188 0 96 0 96 0 89507 0 84108 0 77055 0 58600 0 75695 0 55950 0 34324 0 05658 Design Margins The analytical procedure must account for design variability One method of accounting for variability is to assure that the life consumed during the analysis is less than the life multiples shown in the following table The graphic entitled How Can I Affect Reliability During Analysis in the section called ADV Plan Overview provides a deeper explanation as to how these numbers are derived The following table provides the multiple of life that should be the target of design in order for the reliability objective to be achieved Typical values are shown in bold The design margin values in the right most column reflects the multiple of the specification that must be design to in order to achieve the intended test reliability level Table 37 Design Margin Guidelines Test Reliability Weibull Slope Sori tee un od i 097 _ 2 DL 0 51 J LM
57. then you could decide to actually measure a similar vehicle to obtain the actual Power Spectral Density Plot PSD when that vehicle is driven on the Belgian Blocks Remember that the PSD you measure would need to be run from 252 hours to 1800 hours standard durations X 3 to include all ases These test durations should be reduced normally reduced to GENERAL MOTORS CORPORATION EDSON 2008 14 15 10 11 24 hours with a corresponding increase GRMS level the equations described the vibration section and Appendix G The data collection and analysis to derive the PSD and test is non trivial Some suppliers want to run a vibration test called a sine sweep What is more severe sine sweep or random vibration The simple answer is the random vibration test is more severe Explanation A device will experience fatigue damage when it experiences its resonance frequency Electronic devices attached to the vehicle experience a broad spectrum of frequencies Spanning 10 Hz to 1000 Hz The resonant frequency of all of our products resides within this range of frequencies Random vibration will allow the device to resonate all of the time A sine sweep will only allow the device to resonate for a brief period as the shaker sweeps through the resonant frequency of that product Why are the corrosion tests in GMW3172 more severe than what we see in other specifications The corrosion tests in G
58. under a state of vibration at a certain temperature or during a temperature transition This one hour vibration test is not intended to produce damage but rather place the product into a detectable state so that possible solder cracks formed during thermal fatigue can become detectable under a unique combination of temperature and vibration Validation is also more comprehensive and contains many more tests than Analysis and Development combined Someday this distribution of learning may change but for now we rely upon Validation as the final criteria Every year we strive to develop Analytical or Developmental methods that are equivalent to our Validation Tests to build upon our quick learning strategy If there is a high risk Validation Test that is not being addressed by the current analytical or development task then a small sample version of the Validation Test can be performed during Development to quickly learn if product improvement is necessary This effort will buy you the time needed to effect the needed changes at minimum cost prior to the formal Validation process GENERAL MOTORS CORPORATION EDSON 2008 STRESS STRENGTH NON INTERFERENCE The basic concept behind Validation is to quantify the existence of adequate design margin between the stress distribution and the strength distribution The stress distribution represents the variation between the severe user and the moderate user The strength distribution represents the var
59. under road conditions The process that was used establishing the final vibration test is as follows Vibration time history data was recorded with an accelerometer mounted on the vehicle over a uniquely rough stretch of road Belgian Blocks The time history vibration data was then converted into the frequency domain using Fast Fourier Transform This effort resulted in a Power Spectral Density Plot PSD The PSD was then characterized into energy by quantifying the Square root of the area under the curve This value has the units of Gs Root Mean Square GRMS The duration of time that the vehicle would have been driven on GENERAL MOTORS CORPORATION EDSON 2008 218 219 G that rough stretch of road Belgian Blocks is defined based on the type of vehicle being considered For example a full size pickup truck will spend 600 hours on the Belgian Block road for a lifetime of use combination of the on road test time and the measured GRMS value is used in the following equation to solve for the increased level of GRMS given a shorter duration test Test Time s G xm normal accelerated normal Test Ti C accelerated Where Goma as measured on the vehicle Test 600 hours Test Time 8 hours accelerated How short of a vibration test should we have The common practice is to condense the vibration into an 8 hour test however one could choose to form a test
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61. 150 TBD according to continuous temperature at installation position in the engine compartment Requirement Tested parts shall show no cracking crazing appreciable color changes discoloration cloudiness blistering objectionable shrinkage deformation or loss of adhesion to the substrate between layers of the composite or other changes detrimental to serviceability Test pieces shall comply with the dimensions specified on the drawing after completion of the test GENERAL MOTORS CORPORATION EDSON 2008 108 For parts made of Plastic parts located the engine compartment shall have an additional particularly effective stabilization to avoid the degradation by oxidation of the material in hot air Oxidation Stability 336 h at 150 3 C Requirement No visible indication of local discoloration and or brittleness by material degradation For parts with large plain areas Impact Resistance to GMW14093 Note Test shall be conducted on components If no specific area of the part is assigned on the drawing to meet the impact requirements the entire part must meet these requirements Impact resistance to GMW14093 3 57 min In the as received condition After resistance to temperature The Coding defines the requirements related to the position of the E E Device in the vehicle and the appropriate tests for chemical loads The table identifies chemical origins that are to be covered by the appropriate materi
62. 229 Random Vibration Mounting Location Unsprung 230 Thermal Cycle Profile Used During AIT Vibration 232 Custom Random Vibration Profile For A Bracket Or Electronic Device 229 One Hour Vibration Test After Thermal 236 Evaluation Of Squeaks And Rattles Following Vibration With Thermal Cycling 236 12 02 2 0777 X 2 7 GENERAL MOTORS CORPORATION EDSON 2008 TEMPERATURE 239 TP Se eee Ce ne nee eee 239 Hieh Temperature DUTY 240 242 Demonstrating Reliability For Thermal Fatigue Robustness vis 243 COMMON TEST THERMAL FATIGUE STRATEGY 246 bod M T 248 Power Temperatwe Cycle PTE 250 lo LES DEPO H TE c orm 252 ell GMs aah ER Pls o ms Humid Heat Constant edu 254 riri ILE T HF 255 SI
63. 725 0 726 8 728 6 730 4 732 2 734 0 735 8 737 6 739 4 741 2 120 121 OLD 23 0 24 8 26 6 28 4 30 2 32 0 95 96 97 99 100 203 0 204 8 206 6 208 4 210 2 212 0 195 196 197 198 199 200 383 0 384 8 386 6 388 4 390 2 392 0 295 296 297 298 299 300 F 563 0 564 8 566 6 568 4 570 2 572 0 395 396 397 398 399 400 F 743 0 744 8 746 6 748 4 750 2 752 0 Keeping It All Straight Is Not As Easy As It May Appear GENERAL MOTORS CORPORATION EDSON 2008 VALIDATION REQUIREMENTS QUOTING REQUIREMENTS Quoting Requirements Section 4 of the CTS is the placeholder where the requirements for Validation are to be defined GMW3172 may only be a subset of the total set of requirements and does not cover the non electrical failure mechanisms The dated version of GMW3172 should be identified March 2008 along with the following words in section four of the CTS Example CTS Reliability Paragraph The analytical developmental and Validation mandatory tasks identified in GMW3172 must be performed to ensure adequate product maturity by the end of the product development life cycle The component shall pass the Design Validation and Product Validation environmental and durability requirements of GMW3172 These requirements shall be clearly identified through use of the GMW3172 Coding System resulting from the locatio
64. Belgian Blocks while a car is tested for 85 150 hours on the Belgian Blocks Both of these duration values for cars and trucks are per 100 000 miles of usage Why We Superimpose Thermal Cycling On Top Of Vibration All Vibration Tests have Superimposed thermal cycling during the vibration test This requirement is necessary because a change in temperature significantly increase or decrease the Modulus of Elasticity of plastic materials The point on the temperature scale where this change occurs is known as the Glass Transition Temperature TG value Glass Transition Temperature TG The TG can loosely be defined as a temperature point where a polymer experiences a significant change in properties TG is when a polymer structure turns rubbery upon heating and glassy upon cooling Amorphous polymers are structural below TG Amorphous materials such as ABS go through one stage of the change from a glassy to a rubbery consistency with simultaneous loss stiffness modulus of elasticity or Young s Modulus This stage of going from stiff to flowing is over wide temperature range Crystalline materials on the other hand go through a stage of becoming leathery before becoming rubbery There is loss of stiffness modulus of elasticity or Young s Modulus in both of these stages However crystalline materials have a sharp defined melting point A Basic Understanding Of Plastic As It Relates To Temp
65. C Lasky and Timothy Jensen Indium Corp TERMS amp CONSTRUCTION METHODS amp STATISTICS INTERMETALLICS A chemical compound formed between the metals present in the solder base metal and protective platings Intermetallic formation is necessary for good solder joints but excessive intermetallics can cause brittleness WAVE SOLDERING PROCESS The circuit board is passed over a wave of solder which laps against the bottom of the circuit board to wet the metal surfaces to be joined Used primarily where through hole device attachment is employed GENERAL MOTORS CORPORATION EDSON 2008 50 91 IR REFLOW SOLDER PROCESS A soldering process that uses infrared IR light to generate heat to melt reflow a solder paste The infrared light has a wavelength between visible light and microwave radiation WETTING Wetting is the ability of liquid solder to attach itself to the surfaces being joined through the formation of intermetallic bonds When lead free components are introduced a Wetting Balance Test Meniscograph Test should be run to verify that that the new part meets the minimum response that the supplier has determined is required for their process HON WETTING Note Lead free solder has poorer wetting ability than does leaded solder mercem 1 DE WETTING The following compares the wetability graphs of leaded solder to lead free solder Notice how it takes longer for the lead free solder to develop g
66. Design Margin Using Tools Such As Steinberg Calculations CALCE Tools and Finite Element Analysis Developmental Physical Tests For Reliability Robustness Learning Cycles Small Sample Sizes 1 3 Reliability Robustness Insure Robustness Parity with Exit Criteria Previously Known Good Product Quantitative Evaluation In Validation Testing Methods and Acceleration Factors Quantitative Testing Using Accelerated Reliability Number Demonstrated HASS Pilot gt Q E NOT REAL AND NOT THE BIG PICTURE PRODUCT DEVELOPMENT iY ie LE 0 US 3 Em PS e 545 I think you should more explicit here step two GENERAL MOTORS CORPORATION EDSON 2008 90 GMW3172 CODES AND DESCRIPTION Two Heads Are Better Than One Look for the Wizard he will provide additional information on selected subjects The font used for the Wizard s explanations will be different from the font used for the original content of GMW3172 The Wizard s discussion will provide important knowledge that is not contained in the formal specification The 2008 version of GMW3172 appears in this document EXTERNAL STANDARDS SPECIFICATIONS These are expensive specifications to buy and usually cost more than 100 00 each The supplier should only be required to purchase the specifications that will be required to run the required tests 60068 2 1 60068 2
67. Duration Unsprung mass Six or More Cylinder Engine With Balancing Feature reduced level of vibration testing es Y Yes Yes Yes lt D Yes Yes Yes No No No Yes No No No Three Five Cylinder Engine With Balancing Feature reduced level of vibration testing Yes As Agreed Upon Note a reduced level of engine vibration resulting from special balancing features like a balancing shaft is addressed with codes K and L These vibration profiles are not yet defined in GMW3172 CODE LETTER FOR TEMPERATURE LOADS The Temperature Code letter is very critical as it will affect many different tests The general rule of thumb is Products that are inside the passenger and trunk compartment should use a code Products under the hood that are the farthest away from heat sources or the accumulation of heat should receive a code of F An underhood product GENERAL MOTORS CORPORATION EDSON 2008 102 that is mounted low and forward where post heat would not accumulate should use a code of E What is post heat Imagine driving quickly through the desert and then pulling into the 7 11 for cold drink The engine is hot and suddenly it is sheltered from any moving air that may cool the engine compartment Heat radiating from the engine now rises and fills the engine compartment to a temperature level greater than during normal vehicle use
68. EDSON 2008 186 events The DUT is evaluated with The test shall be performed under monitoring at the end of the test operating type 1 2 However when operating type 3 2 However the device is monitored during the test devices that include relays such as for unwanted activations then the wiper electronics and window modules operating type should be 3 1 Final should be evaluated for proper evaluation at end of test will be function during the pothole mechanical performed under operating type 3 2 shock event operating type 3 2 to ensure unwanted activation does not Two shock tests have to be performed occur Nothing will be monitored with different shock parameters The during the collision mechanical shock tests are conducted according to IEC 60068 2 27 Ea Operating Type Free Body Diagram And Region Definition For Mechanical Shock Ma Front Cradle 1 Region Rear Cradle T LI a Direction of Travel P x uel NS Note the six as noted above refer to the six Cartesian directions of possible motion Products that will or cannot be mounted in all possible directions should be tested in only the applicable directions of force Criteria Functional status shall be class A Table 15 Mechanical Shock Tests By Area Of Vehicle And By Type Of Vehicle Potho
69. Engagement of the snapfit hook e Adequate engagement of the snapfit hook is necessary to ensure robustness under conditions of dynamic loading dirt flash and dimensional variation A Good Rule of Thumb for automotive applications no less than two millimeters of engagement Three to six millimeters is preferred for larger assemblies e The larger engagements are necessary when there are strong dynamic forces working to disengage the parts The engagement that believe 15 necessary for this design IS mm 7 Effect of engagement variation on variation in force e Situations that require extra control of variation in force to assemble should perform the following analysis e Variation in the degree of engagement will translate into variation in force needed to snap the assembly together This translation 307 GENERAL MOTORS CORPORATION EDSON 2008 between engagement variation and force variation can be calculated as follows o Assume k is the spring constant that relates force of assembly to displacement of engagement feature as in force k x displacement o Assume 4 times sigma displacement is the range of variation expected 95 of the time in the engagement feature displacement and sigma displacement 15 the value we will use in our equation o Assume 4 times sigma force will be the range of variation expected 95 of the time in the assembly force _ 2 2 4times sigma e Ax Ak
70. In another hour it will be worn out First of November fifty five This morning the parson takes a drive Now small boys get out of the way Here comes the wonderful one hoss shay Drawn by a rat tailed ewe necked bay Huddup said the parson Off went they The parson was working his Sunday s text Had got to fifthly and stopped perplexed At what the Moses was coming next All at once the horse stood still Close by meet n house on the hill First a shiver and then a thrill Then something decidedly like a spill And the parson was sitting upon a rock At half past nine by the meet n house clock Just the hour of the earthquake shock What do you think the parson found When he got up and stared around The poor old chaise in a heap or mound As if it had been to the mill and ground You see of course if you re not a dunce How it went to pieces all at once All at once and nothing first Just as bubbles do when they burst End of the wonderful one hoss shay Logic is logic That s all I say MOTORS CORPORATION EDSON 2008 Appendix Leaded Solder Guidelines for Thermal Shock and Power Temperature Cycle Testing gt Understanding The Source Of Total Damage During Thermal Cycling In The Lab For Leaded Solder The damage developed during thermal cycling is the product of four components The acceleration factors from these four components are multiplied together to for
71. MT MT 256 OE T E 259 ENCLOSURES TESTS 261 p 261 te snc aciesewedbeaee 262 AU Water Tests Except Seal Evald Olsene eE TER OP 262 PRONTO TO T 263 VG aH F uncon FD TOES 265 DESIGN VALIDATION RESULTS REVIEW 24099 266 PRODUCT VALIDATION 5 1 267 Urol qe rr CET 266 IE TO IER BET OOF AEEA 269 Evaluation Of Engineering Changes After Production eese eene 269 PRODUCT VALIDATION RESULTS REVIEW 270 RE VISIONS TO THIS MANUAL ssscsesssccssssesascsoansnsssotecssssonssceccssesescenassesssotscnssoasess 271 Table of Tables TABLE 1 CODE LETTERS BASED ON LOCATION IN THE 0 100000000000 eee teens 98 TABLE 2 CODE LETTER FOR ELECTRICAL LOADS 101 TABLE 3 CODE LETTER FOR 102 TABLE 4 CODE LETTER FOR TEMPERATURE 104 TABLE 5 CODE LETTER FOR CLIMA
72. Minimum limit value of the ambient temperature at Imi which the system and or E E device are required to Temperature operate Room Ambient Trt Room temperature Temperature Maximum limit value of the ambient temperature at Maximum Temperature Tox system and or E E device required to Maximum limit value of the ambient temperature Post Heating which may temporarily occur after vehicle cut off and Temperature TmaxpH lat which the system and or E E device may be soak back operated for a brief period e g on the engine and in its environment Repaint and Tmaxrps Maximum temperature which can occur during re High Re Paint painting but at which the system is not operated Temperature a Storage Also used to cover high temperature storage and Storage Minimum U Minimum supply voltage at which the system and or Voltage mn E E device is operated during the test Voltage E E device is operated during the test Voltage max E E device is operated during the test 93 GENERAL MOTORS CORPORATION EDSON 2008 OPERATING TYPES The Operating Types and FSC Codes are things you must know to complete the definition of how the test is to be run There is an Operating Type defined for every physical test in this document and you and the supplier must understand and agree as to what that Operating Type is for each test Generally you should use 3 2 for everything where you require continuous
73. N 23 If the testing of 23 samples is not desirable due to program timing or the supplier s facilities then the sample size can be reduced if the test duration is increased Calculations For Increased Testing With A Reduced Sample Size Equation 3 Over Test Equation In 1 C 5 Increased Overtest Factor x In reduced Example We will use an assumed Weibull Slope of 2 for the following because source of failure could result from numerous pretreatments In 1 5 2 Increased Overtest Factor 1 124 8xIn 97 Revised Life Requirement Original Life Requirement x 1 124 275 GENERAL MOTORS CORPORATION EDSON 2008 Appendix Weibull Analysis as Applied To Vibration Test To Failure The basic sprung mass specification for a car requires the product to be tested at 2 84 Grms with a specified Power Spectral Density PSD for 8 hours in each axis This set of test conditions represents one life for 100 000 miles for a car The product should be tested for 8 hours in the X and then tested for 8 hours in the Y direction The X and Y direction are defined as being in the plane of the circuit board The Z direction is to be tested last The Z direction is defined as being perpendicular to the plane of the circuit board vibration testing is performed with superimposed thermal cycling occurring simultaneously with vibration and the product fully monitored Testing in the
74. Tests With Thermal Chamber Duration Temperature min C Figure 36 Thermal Chamber Over Hydraulic Shaker Custom Random Vibration Profile For A Bracket Or Electronic Device The bracket that is used to retain the electronic device should have adequate fatigue life in response to vehicle induced vibration The resonant frequency of the bracket should be measured and should exceed 150 Hz as a generalized rule of thumb to 231 GENERAL MOTORS CORPORATION EDSON 2008 minimize displacement and maintain adequate fatigue life The electronic device that will be attached to the bracket could be tested using the bracket if all parts are available at the same time If timing dictates that the bracket and electronic device be tested at separate times then the following procedure should be followed for testing the bracket The vibration profiles durations and energy levels defined in this document can be used with a simulated device mass to evaluate the fatigue life of the bracket The PSD in GMW3172 is preferred and should be used as a default value since the alternative described below requires significant data collection and analysis resource Alternatively location specific vibration profiles can be quantified by acquiring time domain vibration data taken while traveling on the Belgian Blocks at the Milford Proving Grounds Vibration data should be taken to include frequ
75. The following 24 hour sequence is repeated as many times as necessary per the requirement for the mounting location GENERAL MOTORS CORPORATION EDSON 2008 The following sequence 1 2 3 is repeated three times for a total of 9 hours 1 1 hour at 70 C with the Samples not energized 2 Turn off the chamber heat and energize the samples while Spraying with a 590 saline solution for 1 hour The spray booth should be approximately 35 C with the spray solution at room temperature The pH of the solution should be from 6 5 to 7 2 Operating type 3 2 is to be applied during this hour operating evaluation period with a Functional Status Classification of A 3 Turn off the salt spray and de energize the samples while allowing the parts to cool for 1 hour at 25 C Humidity is uncontrolled during this hour and 15 expected to be high Operating type 3 1 4 A drying period of 15 hours at 25 C with the power Humidity is uncontrolled but is expected to be high This 24 hour test sequence shall be repeated for multiple days as shown in the table After the final cycle perform a Functional Parametric Test within 1 hour The DUT should then be thoroughly washed with clean water to allow for detailed inspection of loss of parent metal or concentrated pitting corrosion that may lead to a loss of seal integrity The enclosure protection test should follow the corrosion test If seal integrity was
76. X S ZMA This variation 4 times sigma force will be centered about the nominal value calculated for the force to assemble e Smaller values of k will result in less variation Smaller k values are often achieved through longer cantilevers Many times longer cantilevers are difficult to package due to space limitations and thus a compromise is established 8 Environmental conditions e The service temperature for the stressed plastic must be greater than the worst case high temperature environmental conditions e The high temperature condition is detrimental because it accelerates the creep phenomenon that may occur in continuously strained plastic An automotive application will experience a maximum temperature either with the car running underhood application or parked in the Arizona sun interior application e The design margin for temperature is the service temperature minus the worst case high temperature environmental temperature The design margin should be a positive number if not either the material should be changed the location changed to an area of a lower temperature or the continuous stresses on cantilevers reduced to near zero e The service temperature for the plastic that will be stressed in this design iS degrees C e The worst case temperature for the snapfit elements of this design 15 temperature design margin is degrees C 9 A compliant mech
77. Z direction will occur for the specified number of hours as listed in table 10 The strategy identified in the test flow and within table 10 is a success run approach where no failures are expected and the 8 hours in the Z axis has been extended to compensate for the reduced sample size from 23 parts to 6 parts If a failure does occur prior to the specified test duration then the testing should continue and a test to failure approach should be adopted The vibration testing in the Z axis should continue at the 2 84 Grms level until at least a total of 4 of the six products fail Product failure is essential in providing the data necessary for performing a Weibull Analysis The analysis process that follows requires that all failure modes be similar Example Six devices are tested for 8 hours in the X direction and 8 hours in the Y direction with superimposed thermal cycling and with no failures These same parts continue testing in the Z direction with superimposed thermal cycling One of the products fails after 19 hours of testing in the Z direction total vibration testing at this point is 8 8 19 35 hours The remaining 5 parts must be tested to failure until at least 4 failures have been accumulated Weibull analysis shall be performed on the time to failure values of the four failures These values shall be plotted on Weibull paper and the reliability at the life requirement 8 hours identified and documented using pro
78. a design review with General Motors data required for determining this resolution is e Identification of all operating limits and design margins e Complete understanding of all hardware and software failures e Identification of how the design margins could be improved e Identification of the barriers to increasing the design margins Assessing the Return on Investment justification for limiting the increase in design margins when improvements are not made Figure 17 HALT Chamber by Thermotron CRUSH TEST FOR DEVICE HOUSING Purpose This test is used to determine if the E E device is able to meet specification requirements when subjected to the mechanical stresses imposed during vehicle assembly Method A represents load imposed by person s elbow while leaning forward on the DUT case Method B represents loading imposed by a person standing on the DUT and or its connector and header Both conditions are representative of possible assembly plant abuse The application of these forces should not generate damaging forces on the circuit board or on components mounted on the circuit board The following loads may also result from the deflection of a seat back or other flexible system near the device GENERAL MOTORS CORPORATION EDSON 2008 182 Locations of Applicability All areas of the vehicle where forces from the hands and elbows of people may be applied to the dev
79. accelerated with increased temperature Water Vapor Diffusion Water vapor can diffuse through the plastic encapsulation around a microprocessor core die and corrode critical connections or interfaces Water vapor upon entering a plastic will also act as a solvent for the plasticizers and these plasticizers will be removed along with the water vapor during periods of drying out This form of degradation is also accelerated with increased temperature GENERAL MOTORS CORPORATION EDSON 2008 38 39 DEGRADATION FROM PHOTOCHEMISTRY Photochemistry Basics Photodegradation chain scission crosslinking activation of polymer macromolecule by photon absorption Photo initiated degradation light absorbed by photo initiators which are cleaved into free radicals which further initiate non photochemical degradation Photo thermal degradation both photo degradation and thermal degradation occur simultaneously and one can accelerate the other Photo aging initiated by solar UV radiation air and pollutants water organic solvents temperature and mechanical stress enhance these processes PROBLEMS WITH RED PHOSPHORUS FLAME RETARDANT Plastic materials used for housings and die encapsulation employ a flame retardant to prevent runaway thermal incidents under conditions of unplanned high temperatures The traditional flame retardants containing bromides and antimony oxides have been deemed environmentally unfriendly
80. amp Strength Change in structure exceeding the maximum allowable deformation as stated in the applicable SSTS requirements or that might affect function packaging appearance or performance requirements of any interfacing subsystem GENERAL MOTORS CORPORATION EDSON 2008 Tear Elastomer Mount Durability amp Strength Loss of static or dynamic performance of the elastomer mount when there is more than 50 rubber crack in any planar section of any elastomeric element or more than 50 separation in any particular bonded surface involving metal or plastic with elastomer Leak Fluid Filled Mount Durability Occurrence of leakage Visible Exterior Cracks Durability Occurrence of cracks detectable by unaided visual inspection cosmetic surfaces Leak Passenger Compartment Durability Occurrence of dust or water intrusion any other evidence of leaks into the passenger compartment including trunk VIBRATION FATIGUE Vibration causes flexure circuit boards with resulting stress component attachments and structure The resulting cyclic strain from the cyclic stress will be concentrated in the lead wires or solder joints The cumulative molecular damage fatigue that results from this flexure results in increased weakness to stress after continued application of the stress This repetitive stress will produce failure that would not otherwise occur if this same level of stress was applie
81. amp minus 1 sigma of stress This force will occur on every reversal of motion of the vibrating bracket device assembly We need to apply this force in the FEA model and identify the highest level of stress occurring in the bracket use a stress concentration factor k of at least 3 We will identify this stress as Stress i1 max 27 19 o Of The Time The Force Will Be 2 Sigma Force 2x14 02 28 04 pounds We need to apply this force in the FEA model and identify the highest level of stress occurring in the bracket use a stress concentration factor k of at least 3 We will identify this stress as Stress2max 4 339 o Of The Time The Force Will Be 3 Sigma Force 3x14 02 42 06 pounds We need to apply this force in the FEA model and identify the highest level of stress occurring in the bracket use a stress concentration factor k of at least 3 We will identify this stress as Stress3 max We know from Miner s Rule that we can build the cumulative damage model as follows Miners Index Calculation Miners Index Value Th Ih N N Where the Miners Index Value represents the fraction of life used up by the collection of different stresses applied gt number of times 319 GENERAL MOTORS CORPORATION EDSON 2008 In our example the values are calculated as follows n BS cycles x 60 _ 60 nine x24 x68 396 5 016 686 cycles reversals n BS cycles x 60
82. and one alternative that has been used is red phosphorus Red phosphorous begins as a natural forming stone and is processed into particles mixed into the plastic molding compound Red phosphorous degrades producing phosphoric acid in the presence of humidity This mixture becomes a strong electrolyte promoting electro migration Electro migration is very similar to dendritic growth Alternatives to red phosphorous are available and should be used in devices containing electronics HUMIDITY INGRESS INTO ELECTRONICS Humidity can permeate into pores or defective openings in electronic devices and damage the inner materials Humidity can travel through materials such as plastic by diffusing through the molecular structure of the base material The effective molecular structure of the water molecule as a gas GENERAL MOTORS CORPORATION EDSON 2008 water vapor is much smaller than the effective molecular structure of liquid water This means that humidity is often a more severe test than liquid water Humidity As A Failure Mechanism In Electronic Systems Water Vapor Diffusion Water vapor can permeate through protective coatings or plastic encapsulations which cannot be permeated by liquid water Water will penetrate openings larger than 2X10 cm through capillary condensation Vapor will pass through smaller openings because there is no surface tension and the molecules are not bonded together scosity Surface Tension and Joi
83. as if it was 90 degrees If any value greater than the critical angle is used the assembly will not come apart as desired When a tool will be used to release the hook attachment access must be provided and the use of a limiter is very important to ensure that the tool does not permanently damage the snapfit cantilever e This assembly will be designed to be disassembled yes or no 5 Identify the engineering parameters for the materials being used in this design GENERAL MOTORS CORPORATION EDSON 2008 306 a Identify the permissible short term strain for the plastic elements that will be experiencing strain during the flexing that occurs during assembly The following are reasonable approximations for the basic types of plastic e 1 for glass filled plastic e 2 for ABS 2 5 for ABS Polycarbonate blend 3 for Polycarbonate e 4 for Acetyl and Nylon e 5 for TPO and polypropylene e The material that will be flexing in this design is e The maximum permissible strain for this material 15 Between 1 and 5 percent b Friction e Friction will be a critical factor in the forces necessary for assembly and for retention of serviceable designs The coefficient of friction is a unit less parameter with a value between 2 and 8 with 5 a good average e The expected coefficient of friction for the two materials that will be Sliding against each other in this design is 6
84. be sustained heat damage to the trace or the circuit board No smoke or thermal event Shall result within the device during or after this test The DUT shall pass all Functional Parametric Tests following this test ELECTROMAGNETIC COMPATIBILITY GMW3097 Pre prototype hardware shall be used to evaluate the capability of the device to meet the requirements GMW3097 GMW3091 and GMW3103 GROUND PATH INDUCTANCE SENSITIVITY The Ground Path Inductance Sensitivity Test was developed in response to a problem where inductance in the wire harness prevented flash programming in the assembly plant This test is optional and should only be required when a condition similar to the above will be present Purpose Identify potential problems that result from the natural inductance developed in the length and routing of the ground wire system Inductance can prevent proper programming of flash memory in the vehicle This phenomenon may not be observed in a bench test unless the inductance consideration 15 intentionally included Locations of Applicability All locations where programming will be required during vehicle assembly Procedure GENERAL MOTORS CORPORATION EDSON 2008 178 179 Monitoring Proper function of flash programming during and at end of test Operating Type The test shall be performed under operating type 2 1 Place a 5 micro Henry inductor in the ground path of a bench te
85. be taken to ensure that the concern does not become a field problem New Product Anticipatory Failure Determination AFD M Design Review 71 This method is to be used to quickly draw attention to potential weaknesses in the product and help in formulating the best ADV plan AFD is a technique of inverting and accentuating the problem formulation Normally in DFMEA one would ask How might this product fail This embodies a natural denial phenomenon and does not help identify the mechanisms that would cause failure to occur The AFD method inverts the basic question so that instead of asking how could it fail one asks How could we make it fail and then How could we make it fail consistently Subsequent questioning explores what conditions would be necessary to ensure that failure would occur consistently The identification of these conditions leads to the identification of the most risk prone failure mechanisms and the conditions that must be managed to prevent failure This process will also ensure that weighted attention is given to failure mechanisms that are believed to have a dominant effect Special attention should be given to these failure mechanisms during test planning and product dissection following the test While the name is trademarked the general concepts of this method are in the public domain and can be used without contracted assistance Doesthe test plan accommodate all of these failure mechanisms How
86. calculate what level of reliability will result when the total population uses our product where the total population is comprised of severe and moderate users Even more cleverly we can reverse engineer this process by determining what level of reliability we desire in the field total population of mixed severity users and then calculate what level of reliability we need on our severe test to achieve the desired field reliability The following graphic Shows the Weibull plot of user variability for cars and for trucks Severe User Defines The Test Probability Weibull Car 1993 94 Opel J Europe Truck 1996 T Utility Weibull 99 8 ie id mile car W2 RRY SRM MED Severe 2 5 0 90 150 000 User W2 RRY SRM MED F 3 S 0 Strength On Test m 99 90 50 00 W2 RRY SRM MED Fei Unreliability F 3 0 2 9 E 2 Y 2 S 10 00 9 4 R 97 7300 Thermal Cycles Larry Edson General Motors 1 00 8 23 2005 07 37 1 00 10 00 100 00 1000 00 10000 00 100000 00 Thermal Cycles 1 1 5387 11 1530 7178 1 0000 B2 1 6530 12 2168
87. cause premature failures Testing must occur to ensure that unexpected weaknesses are not present Vibration The analysis process must simulate the vibration procedure in the design validation section to demonstrate the reliability requirement for vibration A good example of this process is explained in detail for a bracket in Appendix N The process includes converting a long duration low stress test into a higher stress test of much shorter duration The stress under the short duration test is defined and then mapped against the S N curve for the material being stressed The three sigma levels of stress are included in this mapping using Miner s Rule Table 34 is used to determine what portion of the total life available will be used up by the summed combination of the three different sigma stress levels Thermal Fatigue The analysis procedure must simulate the thermal shock and power temperature procedures in the design validation section to demonstrate the reliability requirements Example of Using Test To Field Correlation Assume the situation of a test designed for the severe user with a Customer Variability Ratio CVR of 3 and a failure distribution Weibull Slope of 2 Passing the reliability requirements of 979 on test converts to reliability in the field of 99 5 The field is composed of a wide array of severity users some severe and some not so severe The reliability in the field will theoretically be better
88. conducting AC signal ELECTROMAGNETIC COMPATIBILITY The E E device shall meet the requirements of GMW3091 GMW3097 and GMW3103 EMC Test Plan EMC data results must be supplied to the Validation Engineer for final evaluation CONNECTOR TESTS The following tests in GMW3191 shall be run on the DUT as an assembly Connector Mating Force Ergonomics Connector Retention Force Conector robustness Connector Disengage Force Ergonomics GENERAL MOTORS CORPORATION EDSON 2008 214 Terminal Retention Force FRETTING CORROSION retention of metal pins in the DEGRADATION connector body minimum force required to displace the pin lt 2mm longitudinally in either direction T al Fretting Corrosion connectors sha mee e requirements defined GMW3191 Degradation Test should be applied The following tests from GMW3191 to Bussed Electrical Center shall be run on the DUT as an However an altered form of this test could be used for connection TERMINAL PUSH OUT systems where new designs represent high risk Definition of Fretting Corrosion fretting corrosion general form of CONNECTOR TO CONNECTOR accelerated oxidation that occurs GMW3191 Section 4 8 ENGAGE FORCE at the interface of contacting GMW3191 Section 4 9 materials undergoing slight cyclic relative motion All non noble metals tin are susceptible to some LOCKED CONNECTOR degree
89. current condition Graceful is defined as not producing smoke or creating an overheating condition worst case scenario would be for the device to heat up internally without tripping the fuse and establish a high temperature balance point between the heat being generated and the heat being dissipated This balance point may be just short of the heat needed to open the external fuse or any internal fusible links This balance point condition could result in the generation of high heat on the circuit board and possible smoke Purpose The purpose of this test is to determine if the DUT is able to meet specified requirements when subjected to maximum current allowable by the external protection fuse This test will destroy the device Locations of Applicability All location but only devices that do not have smart protection and are dependent only upon an upstream fuse for protection Procedure Monitoring Graceful death is the expected outcome Monitor only for overheating Operating Type The test shall be performed under operating type 3 2 All circuits are to be protected using the approved application circuit protection device as detailed on the part drawing or specification fuse circuit breaker etc 1 Raise and stabilize the chamber temperature to Tmax 2 Apply Unom to the DUT 3 Short each output through an appropriate resistor value variable resistor suggested to draw a rated
90. detect intermittent failures GENERAL MOTORS CORPORATION EDSON 2008 228 229 Operating test shall be performed under operating type 3 2 Use test methods according ISO 16750 3 Test V Passenger car unsprung masses wheel wheel Suspension Test Duration Cars Test duration 8h for a sample of 23 parts for each X Y and Z coordinate axis perpendicular to the plane of the circuit board of the DUT for a base requirement of 100 000 to 200 000 miles This test duration may need to be adjusted to offset a reduced sample size Test Duration Trucks Test duration 18h for a sample of 23 parts for each X Y and Z coordinate axis perpendicular to the plane of the circuit board of the DUT for a base requirement of 100 000 to 200 000 miles This test duration may need to be adjusted to offset a reduced sample size Loads below 20 Hz are not covered by the test profile stated here In practice high amplitudes can occur below 20 Hz therefore loads acting on the component in this frequency range shall be considered separately The loads between 10 Hz and 20 Hz Shall be covered in the CTS Frequencies above 1000 Hz can be ignored with the approval of GM Engineering Figure 34 Random Vibration Profile Unsprung Mass Unsprung Mounted Random Vibration Profile
91. elimination strategy shall include but is not limited to a lead in solder used to connect the components to the circuit board b lead in coatings on connector terminals and pre solder of wires and components prior to soldering crimping etc c lead in solder for connection of components devices within a higher assembly e g motors Lead in all other applications Prohibited for all other applications Exemptions to Prohibition according to Directive 2000 53 EC Annex Il Lead free in this regard is defined as below 0 1 lead in any homogeneous material Materials and components which are generally exempted from the lead ban are described in the most recent version of Annex Il of the EU ELV directive 0 Batteries electrical components which contain lead in a glass or ceramic matrix lead in copper etc Tin Silver Copper SAC alloys should be used for soldering Finishes shall be engineered to prevent copper migration into tin material GMW3172 shall provide the appropriate validation criteria Assembly processes shall be compatible with the change in components and finishes The selection of parts and materials which could affect system performance must be approved by the Buyers Release Engineer and the Buyers Product Development Group During Technical Reviews or other meetings the supplier is to provide details of process changes controls solder materials including fluxes used and all experience and learning using lea
92. equivalent to that generated by the severe customer over some long period of time or miles driven i e 10 15 years or 100 000 250 000 miles For example the target life for thermal fatigue for inside the passenger compartment is 7300 thermal cycles with a temperature change range of temperature of 43 C We then use our established accelerated testing equations to compose a test that is of equal damage but of less duration using an increased temperature change From a vibration point of view we establish target life as the damage generated by the GRMS value of the PSD profile of a vehicle driving on the Belgian Blocks for a specified number of hours The PUMA Group quantifies the number of hours for a 99 8 severe customer for 100 000 250 000 miles of use We then provide a test with equivalent damage but of a shorter duration and increased GRMS value e The target life for GM vehicles is 10 to 15 years The number of miles associated with this target life is 100 000 to 250 000 miles depending upon the type of vehicle The failure mechanisms for which demonstrate reliability or apply qualitative tests use this target life range as the baseline adjustment in any test defined in GMW3172 should be made for variation in mileage within the range of 100 000 and 250 000 miles difference in test duration for vibration remains effect between cars and trucks see table 20 and 21 However this vibrati
93. exposing reinforcement fibers GENERAL MOTORS CORPORATION EDSON 2008 28 29 Delamination Polymer Composite Durability amp Strength Separation of the adhesive bond interface with the composite and its mating surfaces Loss of Function Durability Loss of function as defined in section 3 1 2 2 of GMW14048 Functional Content of Subsystem Technical Specification within test duration Separation Joint slippage greater than 1 mm Strength Loss of function as defined in section 3 1 2 2 of GMW14048 Subsystem Technical Specification within test duration Separation Joint slippage greater than 3 mm Loss of Trim Height Durability amp Strength Reduction of 10mm or more in trim height due to combined plastic deformation and sag This value is measured at wheel centerline or equivalent Fastener Torque Durability amp Strength Critical Functional Area Occurrence of fastener rotation and any loss of initial torque applied to the joint or any indication of joint slippage Non Critical Functional Area Occurrence of Fastener Rotation and loss of 25 of the initial torque that was applied to the joint or any indication of joint slippage Deformation of Structure Durability amp Strength Change in structure exceeding the maximum allowable deformation as stated in the applicable SSTS requirements or that might affect function packaging or appearance Deformation of Subsystem Interface Durability
94. for each test will be documented in the Test Template by the supplier and with final approval by the GMW31 72 Expert the completed Test Template will become the official Test Plan The Test Plan should also be accompanied by an agreed upon version of the Test Flow as shown in this Handbook GENERAL MOTORS CORPORATION EDSON 2008 12 FREQUENTLY ASKED QUESTIONS 1 What type of product does GMW3172 apply to e This document is intended for electronic devices with circuit boards however the definition of environments and stress levels are appropriate for anything that is to be attached to the vehicle The following concepts are all relevant for things involving vehicles regardless of their electrical content e Mechanical Shock from potholes e Vibration from rough roads e Thermal Cycling from the environment and use Corrosion and Humidity from the environment e Water and Dust from the passengers and the environment 2 Why is GMW3172 so thick compared to other specifications and why does it require a Handbook e This document subscribes to the concept that a good specification must apply a lesson plan approach to QRD to ensure that the right activity occurs at the right time thus ensuring a great product at the right time continued focus on improving A and D activities to prevent V problems is unique to this document The Handbook provides a level of technical understanding not available elsewhere 3
95. from 2 84 Grms to 2 96 Grms The Power Spectral Density values can be proportionately adjusted upward to generate the desired accelerated Grms value by using the Adjustment Factor defined in the following equation Equation 8 Adjustment Factor for Scaling PSD to Grms Grms accelerated Grms normal 2 Adjustment Factor This Adjustment Factor is multiplied times each frequency set point level to establish a new overall energy level increase to match the new required Grms value of 2 96 Most electro dynamic shakers can produce a maximum peak to peak displacement of one inch and this becomes the limiting factor when 299 GENERAL MOTORS CORPORATION EDSON 2008 increasing the GRMS value A safety factor of reduction from this value should be used to prevent damage to the shaker device The peak to peak displacement of an electro dynamic shaker is calculated with the following equation using the lowest frequency of the required spectrum Equation 9 Electro Dynamic Shaker Table Displacement Just Like Vibration Appearances Can Be Deceiving When you go beyond Zebra the dawn s early light Who knows And he worries just worries far There s no telling into the night What wonderful things He just stands there and You might find yourself spelling worries He simply can t stop ls Like QUAN is for Quandary who his top side his bottom Or lives on a shelf bottom side top In a hole in the ocean alone by himself
96. greatest threat to children who have the greatest retention rate for this poisonous metal Industry has responded with an alternative solder that is lead free The composition of this lead free solder is usually tin silver copper Sn Ag Cu Lead free solder has a reduced fatigue life as compared to leaded solder even though the tensile strength of lead free is greater than leaded solder Lead free solder also has greater variability in fatigue life as compared to leaded solder The use of lead free solder creates additional risks as described below The following checklist should be reviewed with the supplier to prevent potential problems and provide for adjustments in test plans as noted e A comprehensive Failure Modes Effects Analysis FMEA or DRBFM must be performed to identify and address lead free solder specific failure mechanisms e Lead free components when used in either a leaded or lead free assembly operation should receive a Meniscograph Test to ensure that the wetting quality will be compatible with the minimum response that the supplier has determined is required for their process e Lead free solders have higher melting points and poorer wetting capabilities as compared to leaded solders The temperature increase can as much as a 34 C over lead based solder The increase temperature results in electronic components being exposed to higher temperatures during assembly These higher temperatures can also increase the
97. gt 2851 Bey 8591 Figure 13 Universal Electronic Device Durability Test Flow For Leaded Solder GENERAL MOTORS CORPORATION EDSON 2008 131 Figure 14 Universal Electronic Device Durability Test Flow For Lead Free Solder Ba 352 9 Ba 352 pue uonaadsu jensiA uonsessig pue Uonsedsu jensiA 1591 JUSLND 4940 0288 OS Buiddius Manes 51581 JOWIAUUOA s AIUETSISAaY WOES sanpo pen Ta JO SAH Pe FUL Bung sapis puy INOW g USI 2 Ul JO SAY pz Bui 2A7 Uy uomedqis Sse Bunids uonepe1jbar uoisoJ107 4 JUANS ayyoig 158 yesu asp P aug 15 104 1 uatudo aAar Ayuprunpg yesung JELLEL 104 405 40558201 Maye OF uaus 13auunaJaqu PUNO PINS HOY PUNO jna4 unus TIRE ABAC peg yews 537 uoy AUO 5036 404 9715 Un pue e1nje1edu
98. losses of varying levels of voltage Please notice that the test sequence is run twice Once with a 5 second dwell at low voltage and once with a 50 millisecond dwell at low voltage Software hardware interaction problems may also result from this test Constant monitoring should be used The interval of time between the voltage reductions can be as long as is necessary to properly evaluate the performance of the product Purpose This test verifies the proper reset behavior of the device It is intended primarily for E E devices with regulated power supply or a voltage regulator This test should also be used for microprocessor based devices to quantify the robustness of the design to sustain short duration low voltage dwells Locations of Applicability devices in any location that may be effected by a momentary drop in voltage GENERAL MOTORS CORPORATION EDSON 2008 198 199 Procedure Monitoring The DUT is to be monitored during the entire test Look for proper reset and return to function Operating Type The test shall be performed under operating type 3 2 Use the test methods in accordance with ISO 16750 2 Reset Behavior at Voltage Drop This test is run twice once at each of the two different durations specified for time at reduced voltage Figure 26 Voltage Drop Test z e 2 gt a Time Seconds Apply the test pulse to all relevant inputs a
99. low melting point is inadequate for automotive applications where temperature maximums vary from 85 C to 140 C Higher Processing Temperatures Are Detrimental To Components Lead free solders have a higher melting point than leaded solder by about 34 C The higher temperatures during re flow or wave soldering will impact the components on the circuit board Electrolytic capacitors are most at risk Damaged components may become more prevalent during DV validation testing as companies apply lead free processing with new components IR reflow processing temperatures of 245 250 C are standard for lead free solder and it is well known that many components can tolerate 260 C for only a few seconds before these component are permanently damaged Kirkendall Voids Copper in direct contact with lead free solder poses the risk of copper migration into the tin matrix The migration of copper into the tin is accelerated with time at high temperature This process produces two negative outcomes the voids in the copper to tin boundary become significant weaknesses when stressed with mechanical shock infused copper increases the compressive stresses in the tin and increases the potential for Tin Whisker Formation Tin Whisker Formation The scientific community is not absolutely sure what produces tin whiskers however the current theory is that compressive stresses in the tin are B primarily responsible for the formation of tin w
100. moment of sealing Purpose This test is applicable to devices that are hermetically sealed and may be Susceptible to permanent damage when shipped in an un pressurized aircraft up to an altitude of 15 240 meters 50 000 feet above sea level Locations of Applicability Applicable to all locations in the vehicle Procedure The following series of steps should be taken to ensure adequate robustness of the structure under pressure to the effects of the low pressure stress resulting from air shipment 1 Quantify the average burst strength of the DUT under internal pressure using finite element analysis or a comparable method 2 Use worst case analysis process considering the variation of material parameters such as the minimum wall thickness and the effects of material weakening relative to temperature effects glass transition temperatures 3 Use table 37 to determine the multiple life design margin necessary 4 1 to ensure the required level of reliability 99 reliability should be used instead of 97 as this is a field based analysis process a Example Worst case analysis shows that the burst pressure of the DUT is 500 absolute pressure b At sea level the DUT is at equilibrium with the internal pressure 101 325 Kpa equal to the external pressure 101 325 Kpa GENERAL MOTORS CORPORATION EDSON 2008 The pressure the freight section of the airplane at 50
101. mounted location Certain locations within a grouping can be significantly less stressful than others from a vibration point of view especially if they are located toward the center of the vehicle Products like the Energy Storage Box for a hybrid vehicle bolted to the floor pan beneath the rear seat of a pickup truck will see approximately 3 Grms in the vehicle when driven on the Belgian Blocks with the corresponding 8 hour vibration test expanded to 1 1 Grms Products mounted closer to the ends of the wheelbase or cantilevered beyond the wheelbase will see vibration levels similar to those specified GMW3172 The process of designing a bracket to hold an electronic device should begin with a clear understanding of what level of vibration should be used The safest bet is to use the vibration profiles defined in GMW3172 as they currently exist In special situations as described above a reduced level of vibration could be used The reduced level of vibration will require that a vehicle be instrumented with an accelerometer attached to the mounting location of interest and the vehicle driven over the Belgian Blocks at the Milford Proving Grounds A few minutes of vibration data is collected and processed into a Power Spectral Density Plot This PSD should be applied to the device under test in each axis for as long as the vehicle would be tested on the Belgian Block Road during the durability test The time on the Belgian Block roa
102. of any duration It is important to realize that the vehicle will generate vibration in all axes at the same time We will run our test on an Electro Dynamic Shaker that operates in one axis only Therefore we will need to run our 8 hour test one axis at a time until we have provided 8 hours of vibration in all 3 axes The full test will take 24 hours The calculated GRMS level for the accelerated test will be greater than that which was measured the vehicle However small increases GRMS energy are equivalent to large reductions in test time The final outcome of this effort is the profile shown for the 8 hour each axis Body Chassis sprung mass vibration test similar process was used for the engine vibration test and the un sprung mass vibration test Why The Vibration Test Is Different Between Cars And Trucks The following vibration tests reference different test durations for cars and for trucks This document will define a truck as a vehicle that will be used in a commercial semi commercial environment A pickup truck would be considered a truck while an SUV or cross over vehicle would be considered a car The vibration test duration is significantly longer for trucks because the vibration GENERAL MOTORS CORPORATION EDSON 2008 damage per mile 15 noticeable greater for a truck than it is for car This can be evidenced by the fact that a truck is tested for 600 hour on the
103. or misplaced forces from hand or elbow during other assembly operations This test is only applicable to connectors with at least 13 mm of area contained in a circle Locations of Applicability location where forces from person s hands or elbow may apply forces to the device during assembly or servicing Procedure Method A Side Forces From Hand Or Elbow Monitoring Evaluate for damage and function at end of test Operating Type test shall be performed under operating type 1 2 The final evaluation shall be performed at the end of the test under operating type 3 2 Functional Status Classification C The connector shall be set up to allow testing on all external surfaces with a 13 0 mm or larger diameter area Subject the connector to an evenly distributed 110 N 24 7 lbs force about any 13 0 mm diameter area for 1 0 s This represents a simulated hand or elbow load that may possibly occur during vehicle assembly Criteria The connector circuit board shall be able to withstand the above mechanical stress without any shear or yield or loss of function or loss of electrical isolation Method B Foot Loads From A Misplaced Step The Method B foot loads are applied to the top of the device connector simulate conditions present in the assembly GENERAL MOTORS CORPORATION EDSON 2008 184 185 plant A product located on the floor of the vehicle prior to the ins
104. snapfit engagement through tactile audible feedback e Bad Example A speaker grille is to be snapfit attached to a door inner panel No guides are employed and there are 12 snapfits around the perimeter that must be engaged all at the same time Placing the grille against the door obscures all vision of the snapfit engagements and the operator is left wondering if all 12 attachments were completed e Identify the guide system you are employing and explain how it fully aligns the snapfits prior to their engagement Snapfits Often Lack Structural Robustness As A Result Of The Requirement To Flex During Assembly An Additional Feature Can Be Added Known As A Limiter Which Protects The Snapfit Feature From Overextension Or Damage GENERAL MOTORS CORPORATION EDSON 2008 310 Damage can occur from the use of pry tools shipping forces or warpage occurring from the stacking of hot parts right out of the mold See the figure below for an example of a limiter The limiter can also become a guide thus serving two functions Identify and explain your use of limiters If you will not be using a limiter then you must explain why not Figure 50 Limiter Example Used In Snapfit Design Limiter and Guide Combination yw Cantilever Example of a Limiter e S Snapfit Release Access Hole The places took him people don t know tried hard to tell took him past Zebra As far as Young Conrad C
105. standard for fast learning based upon the application of extreme vibration and temperature stresses 157 GENERAL MOTORS CORPORATION EDSON 2008 Procedure This Program Crush Test For Device Housing The Crush Test of the Device Housing is only needed if no analytical activity was in place to address this concern A product that is to be mounted on the floor must be able to withstand stepping forces on the housing and on the connectors attached to the housing Connector Installation Abuse ED This test evaluates the susceptibility of the connector to damage during installation Mechanical Shock Pothole And Collision 8 Imagine you have had a significant collision with a tree but your car can be repaired Having repaired the area that came in contact with the tree should you also have to replace all of the electronics in the rest of the vehicle No The 100 G mechanical shock test is used to ensure that non impacted electronics will continue to work properly following such an impact This test should be run as a development test if there is concern for precariously supported electronics hinged devices or other mechanically non robust structure The pothole mechanical shock test should also be run Door Trunk Hood Slam 2 This test is used to evaluate the robust of the device to the high slam Gs developed during closure events Temperature Tests Thermal Performance Development This series of activities
106. submit the DUT to a sustained high temperature to evaluate material degradation performance degradation and diffusion based failure mechanisms The hour temperature repaint and storage portion of the test Tmax rps iS designed to evaluate structural warpage effects temperature post heat portion of the test which is 5 of the total test time is designed to add to the thermal degradation resulting from elevated post heat temperatures Locations of Applicability The 2000 hours of testing is required of all device under the hood of the vehicle and the 500 hours of testing is required for all other locations Procedure Monitoring Constant monitoring is required to detect intermittent failures Operating Type test shall be performed under operating type 2 1 during testing at Tmax rps operating type shall be 3 2 during all remaining portions of the test Test according 15016750 4 High Temperature Test Operation with the following exception he test operating voltage shall be nominal for 8096 low Umin for 10 and high Umax for 10 of the functional tests and or cycles Duration of load is 500 h or 2000 h as per table 4 or per the CTS In situations where increase temperature beyond Tmax 15 warranted due to post heating as Shown for codes F and H the following shall apply 5 of the required high temperature testing shall occur at
107. surface moisture These phenomenon can produce intermittent failures sneak path circuits that my significantly effect function Locations of Applicability locations Procedure Monitoring DUT is monitored continuously during the time that the DUT is energized Operating Type The test shall be performed under operating type 2 1 The DUT will function under operating type 3 2 when energized and during the final evaluation at end of the Conditioning Ensure that the surrounding air has free access to internal devices printed circuit board by the appropriate method e g opening of the component removing of covers This requirement ensures meaningful results within 20 cycles 10 days If free access to internal devices cannot be guaranteed the test parameters have to be changed in the relevant specification Table 18 Description of One 24 Hour Moisture Susceptibility Test Cycle Time Steps 2 hr The DUT shall be powered with Unom when power is to be applied The Moisture Susceptibility Test consists of 10 days as follows The New Moisture Susceptibility Test Replaces The Frost Test And The Dew Test Repeat This 24 Hour Profile Every Day For 10 Consecutive Days lt 3 minutes lt 3 minutes lt 3 minutes am 85 and 95 98 Humidity 16 hrs Hot And Humid 0 2 C Humidity Uncontrolled When Cold 24 hrs Functional Cycling The component
108. testing Increased strain resulting from extended thermal range applied in test Coffin Manson Equation 2 65 Coffin Manson Acceleration Factor E field A dwell period at the end of each change of temperature allows the continuation of creep to occur within the solder until the stresses resulting from the temperature change have dissipated The effect of testing with less dwell time than would occur in the hands of the customer must be comprehended in the calculations Longer dwell times will result in more damage per cycle However damage accumulation is not linear with time There is a diminishing level of damage accumulation with time and the optimum dwell time needed for maximum damage per unit of time for lead free solder is approximately three times that needed for leaded solder The optimum dwell period of lead free solder is 10 minutes Empirical testing has shown that the acceleration factor resulting from a decreased dwell period is Dwell Time Dwell Time Acceleration Factor Dwell Time The rate of change of temperature has a small effect on lead free solder More damage is created with a slow ramp rate than with a fast ramp rate This is the exact opposite of what occurs with leaded solder The effect of the ramp rate is defined in the following equation Ramp Rate Acceleration Factor 1 22x Ramp Rate 0757 highest temperature reached during thermal cycling have significant effect
109. the elevated post heating temperature level Interior parts that may see paint booth reheating shall be exposed to lt for the first 60 minutes of the 500 or 2000 hour durability test The DUT shall to be exercised for at least 1 life of electrical operational cycles during the High Temperature durability test The functional cycling scheme shall exercise the DUT and allow for detection of degradation or failure Of the operating temperature range table 4 is the temperature load Duration of load is 500 h 2000 h or per the CTS In situations where an increase in temperature beyond Tmax is warranted due to post heating temperature codes F and H the following shall apply 5 of the required high temperature testing shall occur at the elevated post heating temperature level Tmax pu GENERAL MOTORS CORPORATION EDSON 2008 test operating voltage shall be during and after the test Any nominal for 80 9o low for 10 and inputs outputs an incorrect state or high for 10 9o of the functional tests any incorrect communication and or cycles messages shall be considered nonconformance to specification Criteria requirements Functional status shall be class A All functional requirements shall be met THERMAL FATIGUE TESTING The expansions and contraction of dissimilar materials resulting from changes in temperature will produce cyclic fatigue in the mater
110. this product can be placed into production with confidence that customers will be delighted and that GM reputation of quality and reliability is maintained If additional effort must be made during start of production such as GENERAL MOTORS CORPORATION EDSON 2008 268 Screening Activities then this should be agreed upon during this final Criteria Product Validation Results Review This is the final opportunity to Procedure prevent warranty expense Actions necessary to mitigate risks should be Perform the design review per defined and discussed with Appendix B and take appropriate management action REVISIONS TO THIS MANUAL Revision Date Change Number Green Oct First Introduction of User Manual Old thermal fatigue Cover first 2005 calculations 12 copies edition Blue Cover Nov Official distribution to Validation Engineers with HP no revision 2005 revised thermal fatigue calculations number Blue Cover Dec Change to Load Circuit Over Current Test Addition of revision 2005 Meniscograph Test Small changes to test flows number 1 Rev 2 Jan Addition of Ground Interconnect Short To Battery Test 2006 Additional notes for thermal shock test Appendix M added Rev 4 Mar Expanded explanation of failure mechanisms and 2006 terms Changes to thermal fatigue testing cycles spec and handbook will agree Change in criteria during salt mist corrosion testing Clarification of tests fo
111. those drops would be salt water and may lead to a serious corrosion problem Functional Status shall be class A The DUT shall experience no damage or degradation of performance The part shall pass the Functional Parametric Test during and at the end of the test SEAL EVALUATION The Seal Evaluation Test is a severe process that evaluates the ability of the enclosure to seal out water Pre heating the device to Tmax before it is cold quenched in freezing salt water increases the test severity This test is appropriate for underbody GENERAL MOTORS CORPORATION EDSON 2008 locations within approximately 20 inches from the ground that may become submerged or splashed This test is also appropriate for devices that must be very well sealed based on prior field experience Purpose To verify the DUT functionality after exposure to thermal shocks induced by heating in air and cooling in water The test should be used for sealed electrical devices to evaluate the effectiveness of the seals This test is the default test when the second IP code is 8 Locations of Applicability This test is applicable to areas that could possibly become submerged Areas within the vehicle such as depressed areas in the floor pan or truck are also areas that could contain water This test is also required of all devices that are to be potted Procedure Monitoring The device is only monitored during the post test evaluation
112. tightly packed The Weibull Slope parameter is referred to as Beta Weibull Slopes All Shapes Probability Density Function 0 10 Multi Plot point 5 The distribution moves e 15 0 Tm from an exponential slope i W2 RRX SRM MED shape toward a compact ats slope 2 normal shape with slope 3 increase in slope value uc Fz0 Sz0 D LETI slope 4 0 04 W2 RRX SRM MED E207 Normal 6 slope 6 W2 RRX SRM MED 1 2 F20 5 0 0 40 00 80 00 120 00 160 00 200 00 Time t 1 0 5000 11 89 7400 0 2 1 0000 112 89 7400 0 B3 2 0000 113 89 7400 0 B4 3 0000 14 89 7400 0 85 4 0000 115 89 7400 0 B6 6 0000 n6 89 7400 0 CHARACTERISTIC LIFE The other important parameter in the Weibull distribution which is an indicator of the general location of the distribution is the Characteristic Life The Characteristic Life occurs 63 of the way through the distribution and can be thought of as similar to the average The Characteristic Life is referred to as Eta Using The Weibull Distribution PDF 0 01 Weibull Data 1 Weibull Probability 5
113. to potentially disruptive shorts to battery supply voltages short to ground and open circuit conditions This analysis is also performed to verify the ability of components and conductors to survive short open conditions Locations of Applicability Applicable to all devices in the vehicle Procedure Use a circuit analysis program to perform the Short Open Circuit Analysis Criteria Verify ability of components conductors to survive short open conditions No component limit value should be exceeded that may result in damage during the analysis Must meet FSC C under conditions short open LEAD FREE SOLDER CHECKLIST Purpose Review changes exposure to manufacturing temperatures and effects from the change in materials resulting from the use of lead free soldering processes Ensure that components are adequately robust against the higher processing temperatures and the need for humidity control of parts in storage Locations of Applicability Applicable to all devices in the vehicle Procedure Use Appendix E as a checklist for DRBFM activities Criteria Provide full disclosure throughout the supply chain regarding risks when lead free solder is used All risks are to be addressed and mitigated through the design review and DRBFM process GENERAL MOTORS CORPORATION EDSON 2008 MECHANICAL ANALYSIS CIRCUIT BOARD OR OTHER CRITICAL ELEMENT RESONANT FREQUENCY AN
114. wil we assess the design margins for these failure mechanisms The management of problem prevention communication between elements of the Supply Chain must be managed through the Design Review Process The extent of this communication should extend to at least the Tier 3 level when possible documented communication process must be evident and concerns between tiers must be communicated to the GM engineering team through the design review process Example If we begin to use lead free solder at the Tier 1 supplier level which results in a melting point increase of 30 over tin lead solder how will this be communicated to the Tier 2 GENERAL MOTORS CORPORATION EDSON 2008 Suppliers that will be supplying discrete components that must now see this additional temperature rise What is the feedback of risk level from the Tier 2 supplier for this situation e Design Reviews Between ADV phases using Design Review Based on Test Results DRBTR Design Reviews 3 5 o Detailed dissection of the tested products is essential to uncover all available information Looking for what is not obvious is essential and the results must be reviewed with General Motors o How much design margin exists for each failure mechanism How sensitive are the dimensions or processing parameters that affect the weak points in our design that limit our design margin How can we minimize the effect of variation on these parameters on the de
115. within a circuit board The pin has a shape that resembles the head of a needle The inner hole in the needle head collapses to some degree as the pin is pressed into the VIA barrel opening The force necessary to press the pin into the barrel is a function of the geometry and the coefficient of friction of the materials being GENERAL MOTORS CORPORATION EDSON 2008 used High levels of friction can result in high force requirements with possible damage resulting in the VIA barrel or bending of the circuit board or the pin High forces may also result in the shedding of plating slivers during installation These slivers can later lead to unintended shorting of nearby circuits The pin Should have an under layer plating of nickel if the pin is over plated with tin This nickel under plating is used to mitigate the potential for tin whisker formation on the pin Fretting corrosion may occur if the pin becomes loose in the barrel and the barrel pin system experiences relative motion from thermal cycling or vibration Force Of Pressing Pin Into Barrel Produces Stress Points Noted by Blue Arrows Pin Pressed Into Barrel Forces Circuit Board Forces 7 VIA Barrel Figure 3 Compliant Pin Construction GENERAL MOTORS CORPORATION EDSON 2008 58 59 SELECTIVE SOLDERING Selective soldering is a process for soldering thru hole components on the bottom side of an assembly In a selective soldering process a r
116. worst case composite derived from the trucking rail and air profiles as specified in ASTM D4728 This test is to be conducted on one box of product in its final shipping container Vibrate the shipping container for 25 hours in each of the three mutually perpendicular directions for a grand total of 72 hours Use a vibration test fixture that allows the shipping container one box of product to move freely in the vertical axis of the vibration table A suggested fixture would consist of a base plate with four upright posts that are slightly larger than the shipping container Provisions should be made to allow placement of the package in all three directions Use the random vibration profile shown below in table 34 GENERAL MOTORS CORPORATION EDSON 2008 266 267 Frequency Hz Criteria The FSC code is not applicable to this test The box of product is to be opened and thoroughly inspected for possible damage following the total 72 hour vibration test Additionally the product must meet the functional and parametric requirements specified in the CTS The GM Design Release Engineer may allow selected evaluation of statistical Sample of parts as opposed to all parts contained shipping container to be evaluated Parts Should be randomly chosen from all quadrants of the shipping container if only a sample is taken SCREENING DURING PRODUCTION High risk an
117. worst case in terms of the m values and that will be the target material used in this document m 2 65 Coffin Manson Acceleration Factor 22 20 73448 field gt Thermal Shock Step 3 Lead Free Solder Applying The Acceleration Factor For Dwell Time Effect To The Thermal Shock Cycles We are using an optimum damage per unit of time dwell period during testing of 10 minutes both hot and cold While this is optimum on a per unit of time basis it does not encompass all of the damage that would have been generated by the severe customer using a longer dwell period The following acceleration factor accounts for the lost damage with a shorter dwell period Dwell Time Dwell Time Acceleration Factor Dwell Time 10 136 Dwell Time Acceleration Factor 815 gt Thermal Shock Step 4 Lead Free Acceleration Factor Resulting From The Thermal Ramp Rate The thermal ramp rate used in making the temperature transitions has a small effect on lead free solder I have included the equation for this effect for completeness of the model This factor is derived from the modeling work of J P Clech and is shown in figures 14a of reference 14 Slower ramp rates will result in an acceleration factor for lead free solder while faster ramp rates will result in an acceleration factor for leaded solder Ramp Rate Acceleration Factor 1 22x Ramp Rate 0757 Ramp Rate Acceleration Factor 1 22x 1 5 075
118. 0 S9Sn87Zn3Bi The Above Graphic From Dr Ronald C Lasky and Timothy Jensen Indium Corp Leaded vs Lead Free Comparison Relative To Dwell Time Lead Free Requires A Longer Dwell Time Optimum Dwells OPTIMUM DWELL TIME E m O3 STRAIN ENERGY PER UNIT OF TIME MPs Min 00 Figure Damage rate or stram per unit of time solid lines primary axis and test duration given as months to 5000 cycles dashed line secondary axis as ion of dwell time for SAC and SnPb CBGA assemblies in thermal cveling from 0 C to 100 C Damage As A Function Of Dwell CEGA TC data after Bartelo et al APEX 2001 Cold and het dwells vary from 7 to 112 minutes 0 100C Strain Energy Models 1000 Test Data 401250 Strain Energy Models a 10 1256 lest Data SAC SnPb LIFE Life ratio 1 109 DELL TIME MINUTE Figure 9 Predicted and experimental trends of SAC to SnPb median life ratio as a function of dwell time in Thermal Cvcline CBGA data points are from 17 failure distributions in 23 The Above Graphic From Dr J P Clech GENERAL MOTORS CORPORATION EDSON 2008 44 45 Concerns With Bismuth Sn Ag Bi on Sn Pb Finish ED UnTested to 25 SOvm 111185 Sn Ag Bi with Pb contamination after 1 reflow bob Heat Impurities Source Sn Ag Bi with Pb contaminatio
119. 0 5 I min 5 opening average 75 I min 5 Note A reduced flow rate 60529 may be except accepted if nozzle 6 3 the mm pressure diameter and nozzle size are maintained As in item 6 IEC Minimum 3 min When the second IP code is 8 use the Seal Evaluation Test explained in the following section unless stated otherwise in the CTS Criteria Careful observation good dissection of the DUT following the water test is essential in detecting the following requirements Water must never reach the circuit board or critical electronic components connections by means of drip spray splash or submersion as defined by the protection requirement code Additionally water may not accumulate within the container and reach the above defined critical elements A design that employs a circuit board within a box within a second box may M have water penetrate the outer box as long as it does not pass into the inner box and contact the critical electrical elements Water management as a strategy is permitted as long as no water ever reaches the critical electronics or electrical connection points It should be realized that the water used this test is convenience for the contaminated road splash that may reach the device in the real world application We may see a few drops of water on the circuit board during this test and believe that it would have no effect In the real world
120. 0 Grins or Chamber Max in Celsius No Vibration a a nin da rege S accumulation 40 25 e Vibration can start at re or 20 Gr re acceleration type senso s et may need to start lower All ramp rates sre E 1 as fast E slower ramps may be necessary if Tmax will exceed A 130 special analysis required 100 2 Tmin Note Tmax should be predefined ESI from the melting point of the materials do not melt the materials SUCCESS RUN TESTING Success run testing operates without the intention of producing failures test requires a specified number of samples under a defined stress condition for a defined duration of time or cycles The reliability and confidence requirements dictate the number of samples that must be subjected to such a test The success run equation is used to determine the number of samples however the following nomograph can also be used to determine how many samples are required Draw a line between the confidence desired on the right and the reliability desired on the left Read the number of samples at the intersection of your line and the O failure GENERAL MOTORS CORPORATION EDSON 2008 62 63 diagonal line If a failure occurs on test the revised reliability can be obtained by following the nearest curved line downward until
121. 000 feet 15240 meters is 11 kpa d The net internal pressure in the DUT is 90 Kpa at 50 000 feet 101 11 90 e The burst pressure must be at least 4 1 times the functioning pressure of 90 90X 4 1 369 f Our worst case burst pressure is 500 which exceeds our required value of 369 Kpa g This product meets the requirement by analysis Criteria The worst case burst pressure of the DUT must exceed the functioning pressure during air shipment by a factor of 4 1 SNAP LOCK FASTENER ANALYSIS The inclusion of the Snap Lock Fastener Analysis is the result of many Validation and Field problems where the attachment of the device to the vehicle was inadequate The Plastic Snapfit Design Worksheet in Appendix will guide the engineer through the snapfit design process Finite Element Analysis may also be used This analysis requires that the short term strain generated during assembly remain within the elastic limit for the material being strained during assembly usually plastic The overstraining of plastic snapfit attachments results in the stressed element exceeding its elastic limit resulting in the permanent deformation of the attaching member This permanent deformation results in a decrease in attachment engagement and the device can easily be dislodged with mechanical shock or vibration The highly weakened over stressed member will eventually fail fr
122. 1 Low Temperature Temperature 15012103 1 15012103 1 Dust IEC 60068 2 13 Altitude IEC 60068 2 29 ra Shock Operation Repetitive Events Potholes IEC 60068 2 11ka Salt Mist as 5016750 2 4 Road Vehicles referenced in ISO 16750 4 Environmental Conditions and Testing for Electrical Equipment IEC 60068 2 27 Mechanical Shock Non Repetitive Events Crash Dust and Water eee 91 GENERAL MOTORS CORPORATION EDSON 2008 PARAMETER TOLERANCE Unless stated otherwise the following shall define the test environment parameters and tolerances to be used for all validation testing Ambient Temperature Spec 3 C Room Ambient Temperature 23 5 C Yo Room Ambient Relative 30 70 Humidity Chamber Humidity Spec 5 Voltage Spec 0 1 V Vibration Spec 0 2 X gn or spec 20 whichever is greater s Are Those Straight Lines Curved GENERAL MOTORS CORPORATION EDSON 2008 92 TEMPERATURE AND VOLTAGE DEFINITIONS Temperature and Voltage Definition It is very important to establish Tmin and Tmax as described in the table below as these will be used in many tests Please see the section on temperature codes for insight on how to choose the temperature code Why is there no Storage Temperature Test Cold storage does not affect any type of failure mechanism other than Tin Pest The re paint temperature effectively handles high temperature storage
123. 121 0 15 59 0 115 239 0 215 419 0 315 599 0 84 119 2 16 60 8 116 240 8 216 420 8 316 600 8 GENERAL MOTORS CORPORATION EDSON 2008 118 119 117 4 115 6 113 8 112 0 110 2 108 4 106 6 104 8 103 0 101 2 99 4 97 6 95 8 94 0 92 2 90 4 88 6 86 8 85 0 83 2 81 4 79 6 77 8 76 0 74 2 72 4 70 6 68 8 67 0 65 2 63 4 61 6 09 8 58 0 56 2 54 4 52 6 50 8 49 0 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 62 6 64 4 66 2 68 0 69 8 71 6 13 4 75 2 77 0 78 8 80 6 82 4 84 2 86 0 87 8 89 6 91 4 93 2 95 0 96 8 98 6 100 4 102 2 104 0 105 8 107 6 109 4 111 2 113 0 114 8 116 6 118 4 120 2 122 0 123 8 125 6 127 4 129 2 131 0 C 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 F 242 6 244 4 246 2 248 0 249 8 251 6 253 4 255 2 257 0 258 8 260 6 262 4 264 2 266 0 267 8 269 6 271 4 273 2 275 0 276 8 278 6 280 4 282 2 284 0 285 8 287 6 289 4 291 2 293 0 294 8 296 6 298 4 300 2 302 0 303 8 305 6 307 4 309 2 311 0 C 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 24
124. 183 2 185 0 186 8 188 6 190 4 192 2 194 0 195 8 197 6 199 4 201 2 C 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 F 312 8 314 6 316 4 318 2 320 0 321 8 323 6 325 4 327 2 329 0 330 8 332 6 334 4 336 2 338 0 339 8 341 6 343 4 345 2 347 348 8 350 6 352 4 354 2 356 357 8 359 6 361 4 363 2 365 0 366 8 368 6 370 4 372 2 374 0 375 8 377 6 379 4 381 2 C 206 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 492 8 494 6 496 4 498 2 500 0 501 8 503 6 505 4 507 2 509 0 510 8 512 6 514 4 516 2 518 0 519 8 521 6 523 4 525 2 527 928 8 930 6 532 4 534 2 536 537 8 539 6 541 4 543 2 545 0 546 8 548 6 550 4 552 2 554 0 555 8 557 6 559 4 561 2 GENERAL MOTORS CORPORATION EDSON 2008 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 3 5 3 6 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 6 2 8 674 6 676 4 678 2 680 0 681 8 683 6 685 4 687 2 689 0 690 8 692 6 694 4 696 2 698 0 699 8 701 6 703 4 705 2 707 708 8 710 6 712 4 714 2 716 717 8 719 6 721 4 723 2
125. 21 GENERAL MOTORS CORPORATION EDSON 2008 References 1 Steinberg Dave E Vibration Analysis For Electronic Equipment Third Edition John Wiley and Sons 2001 Hobbs Gregg K Accelerated Reliabilit Engineering HALT and HASS John Wiley and Sons 2000 Lipson Charles and Sheth Narendra J Statistical Design and Analysis of Engineering Experiments Nelson Wayne Accelerated Life Testing John Wiley and Sons 1990 5 Peck Steward Comprehensive Model for Humidity Testing Correlation IEEE Catalog 86CH2256 6 1986 Technology Report 5 Fundamental Concepts of Environmental Testing in Electricity and Electronics Tabai Espec Corp 1998 Azar Kaveh Electronics Cooling Theory and Applications Short Course 1998 8 White F M Fluid Mechanics Second Edition Pg 60 McGraw Hill New York 1986 9 Clech Jean Paul Solder Reliability Solutions From LCCCS to Area Array Assemblies Proceedings From Nepcon West 1996 There are letters yet to be discovered With us every day just waiting to be uncovered Will you be the one who dispels the illusion Helping us all to clear the confusion The boundary crossers are few But we all thank God for those that do 10 Clark Dana W AFD and Inventive Troubleshooting Ideation International Inc 2000 1 Edson Larry Design Of Integral Attachments And Snapfit Features In Plastic GM Publica
126. 22 2 Soak the DUT un powered until its temperature has stabilized to T min 3 Power up the DUT and inject the battery voltage dropout test profile with the following parameters from variation A in Table 15 4 Perform a Functional Parametric Test at 14 volts zone E1 Figure 27 Battery Voltage Dropout Profile Battery Voltage Dropout Profile To Be Run With Four Different Time Variations And At Two Different Temperatures 14 T1 Volts T2 T3 Voltage Time gt Table 19 Battery Voltage Dropout Test Durations Time s 28800 7200 5 Proceed through the test profile and perform a Functional Check at Umin between and T time intervals zone 2 Variations 6 Perform a Functional Parametric Test after the T3 time interval at 10 volts zone E3 7 Repeat steps 3 through 6 three additional times for the variations B C and D 8 Repeat steps 2 through 7 at Tmax Note The reduction to 1 volt is to check for power reset functionality This would be appropriate for micro controller devices and external prom memories The time at 1 volt is undefined but should be greater than 30 seconds Criteria Functional status should be as shown depending on the zone per figure 27 GENERAL MOTORS CORPORATION EDSON 2008 200 201 SUPERIMPOSED VOLTAGE TESTS Two different Superimposed alternating voltage tests are shown The beyond normal lev
127. 3 244 245 246 247 248 249 250 251 252 253 254 255 422 6 424 4 426 2 428 0 429 8 431 6 433 4 435 2 437 0 438 8 440 6 442 4 444 2 446 0 447 8 449 6 451 4 453 2 455 0 456 8 458 6 460 4 462 2 464 0 465 8 467 6 469 4 471 2 473 0 474 8 476 6 478 4 480 2 482 0 483 8 485 6 487 4 489 2 491 0 GENERAL MOTORS CORPORATION EDSON 2008 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 F 602 6 604 4 606 2 608 0 609 8 611 6 613 4 615 2 617 0 618 8 620 6 622 4 624 2 626 0 627 8 629 6 631 4 633 2 635 0 636 8 638 6 640 4 642 2 644 0 645 8 647 6 649 4 651 2 653 0 654 8 656 6 658 4 660 2 662 0 663 8 665 6 667 4 669 2 671 0 11 47 2 45 4 43 6 41 8 40 0 38 2 36 4 34 6 32 8 31 0 29 2 27 4 25 6 23 8 22 0 20 2 18 4 16 6 14 8 13 0 11 2 9 4 7 6 5 8 4 0 DD 0 4 14 3 2 5 0 6 8 8 6 10 4 12 2 14 0 15 8 17 6 19 4 21 2 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 132 8 134 6 136 4 138 2 140 0 141 8 143 6 145 4 147 2 149 0 150 8 152 6 154 4 156 2 158 0 159 8 161 6 163 4 165 2 167 168 8 170 6 172 4 174 2 176 177 8 179 6 181 4
128. 3 4 pulsed dust injection using Talcum Powder or the SAE J726 procedure constant dust dispersal This test shall be conducted using SAE J726 Fine Grade Dust and should occur for a period of 8 hours Criteria Functional Status shall be class A The DUT shal experience no damage loss of function degradation of performance when GENERAL MOTORS CORPORATION EDSON 2008 energized and evaluated following the dust test WATER ALL WATER TESTS EXCEPT SEAL EVALUATION The water tests using the codes 2 3 AK 6K and 9 are designed to ensure that the housing is effective at protecting the circuit board from the problems introduced by water contamination Consider adding a UV soluble dye to the water for easier ingress detection with black during post evaluation Purpose Determine if the enclosure meets the International Protection Requirement when specified the second characteristic IP code Locations of Applicability This test is applicable to all areas not subjected to the Seal Evaluation Test Procedure Monitoring The device is only monitored during the post test evaluation Operating Type The operating type shall be 1 2 during the water test The operating type shall be 3 2 during the post test evaluation Devices that will be tested to the code 2 requirement shall be oriented as follow A device mounted inside the vehicle is designed such that the connect
129. 3744 0 9998 83 2 0000 n3 4 1828E 4 0 We chosen 7300 thermal cycles as our test which corresponds to 99 8 severe user for cars and a 99 7 severe user for trucks We will establish our thermal cycling test based on 7300 thermal cycles The process of reverse engineering allows us to determine that 97 on test will produce in excess of 99 in the field The underlying strategy in GMW3172 is to have a reliability requirement that is significantly better than our nearest competitor A benchmarking of Honda and Toyota electronic controllers showed their field reliability at 100 000 miles to be 99 GM chose to establish a field reliability GENERAL MOTORS CORPORATION EDSON 2008 88 requirement of 99 5 which is 50 more stringent than 99 in terms of a failure rate The reliability requirement needed to achieve 99 field reliability is 97 when a 99 8 severe user test is utilized This strategy provides many advantages during Validation Testing A smaller reliability number will demand fewer samples and less time when Quantitative Testing methods are used in Validation Internal Thermal Ramp Rate of 1 9 Degrees C min Probability Weibull Internal Thermal Ramp Rate of 6 Degrees C min Probability Weibull
130. 41 THERMAL SHOCK TEST PROFILE 249 FIGURE 42 AIR TO AIR THERMAL SHOCK sese ese eee ee 240 FIGURE 43 PARTS INSIDE THE AIR TO AIR THERMAL SHOCK CHAMBER ecce enne 250 FIGURE 44 POWER TEMPERATURE CYCLE LEAD FREE DWELL TIMES SHOWN ct 251 PIGURE 4S CYCHIC HUNIDITY TEST PROFILE benz emer aD pia Dus 223 FIGURE 46 NORTH AMERICA CORROSION MAP eet estre reae ren eese Eee dogs vus pee ruote e VE MEE e Po pere P 258 FIGURE 47 SALT SPRAY CORROSION CHAMBER cssecesscesscesconescvecoseccescavsecessoucsoetsnceescusroneessacsvecosecceseess 259 265 FIGURE 49 2 279 FIGURE 50 LIMITER EXAMPLE USED IN SNAPFIT DESIGN 6 00 4 00 00 0 313 Table of Equations EQUATION 1 SUCCESS RUN EQUATION cccccscssescsssscsscscsecscsescsessessssesassesassesacsecsesassesassesacsecacsecacsecacsees 277 EQUATION 2 SAMPLE SIZE EQUATION T 217 S OVER 277 EQUATION 4 LEAD FREE ACCELERATIO
131. 46 67 948 792887 91 700 9 7 612 17 962 28 624 39 308 50 000 50 691 71 376 822038 92 587 18 3e778 94151 14 581 202024 25 471 304 921 36 371 414823 47 274 52 726 58 177 63 629 69 079 74 529 79 976 85 419 90 849 96 4222 19 3 582 8 677 13 827 18 988 24 154 29 322 36 4291 39 660 64 8230 50 000 554 170 60 340 65 509 70 678 75 846 81 011 86 173 91 322 96 418 10 660697 166226 254857 352510 45 169 54 831 64 490 76 142 83 774 935303 20 32406 8 251 132147 18 055 22 967 274 880 22 795 372710 422625 472542 52 458 5762374 629289 67 205 722119 772033 81 945 8648523 91 749 966594 If you stay home with Zebra You re stuck in a rut But on beyond Zebra You re anything but ramble scramble through swampf and through swumpf Where the letters get better Like letters like HUMPF There s a real handy letter What s handy about it You just can t spell Humpf Humpf a Dumpfer without it Dr Seuss On Beyond Zebra GENERAL MOTORS CORPORATION EDSON 2008 2 8 Appendix Lead Free Solder Considerations The global move to eliminate the use of lead in consumer products through legislative actions has growing applicability for the automotive industry Circuit boards that reach landfills can create the potential for the lead on the circuit board to leach out of the circuit board and into the ground water Lead represents the
132. 7 11 Gold contacts be used at elevated temperatures 12 Gold contacts should not be mated to tin contacts 13 Gold contacts are not recommended for Hot Make and Break applications STRESS CORROSION CRACKING Stress corrosion cracking is the combined effect of cyclic stress and crevice corrosion resulting in a reduction of material cross section at a single crevice location Most prominent in non ferrous metals as the corrosion does not appear on the surface of the material but is actively at work at the tip of the corrosion crack CREEP Creep is the slow plastic flow of material without fracture Temperature accelerates the creep process Creep is prominent in plastic material and in solder during thermal fatigue GENERAL MOTORS CORPORATION EDSON 2008 Solder Creep Over Time Primary Secondary Tertiary Creep Creep Creep Strain Rate 17 minutes TEMPERATURE AGING OR DIFFUSION BASED DEGRADATION Time at High Temperature Molecules move faster at higher temperatures and can travel places beyond where they were originally intended to exist This leads to the inter diffusion of materials and can result in degraded performance in electronic components and degraded fatigue life of solder joints This process will also result in plastics becoming more brittle with extended time at high temperature Degradation From Ultra Violet Light Ultra violet light produces molecular damage in plastics This damage is
133. 9697 gt Thermal Shock Step 5 Lead Free Acceleration Factor For The Maximum Temperature Used During Testing 285 GENERAL MOTORS CORPORATION EDSON 2008 maximum temperature used during testing can have significant effect on the amount of creep that occurs during the thermal transition Creep occurs much faster at higher temperatures In this example we will use a 95 high temperature during thermal shock to accelerate the test and we are not worried about functioning at this temperature because we do not energize the device during thermal shock 1 1 21054 Highest Temperature Acceleration Factor 279 Trestmax 273 2185x 1 Highest Temperature Acceleration Factor a aseo 1 1804 gt Thermal Shock Step 6 Lead Free Total Multiplication of Acceleration Factors 2 65 136 1 _ 1 AF 4 Dwell time E 122x rampra te x Unum Trostmax 273 j Dwell Combined Acceleration Factor 20 73448 815 9697 1 1804 19 344 5475 344 263 03 Number of Cycles gt Thermal Shock Step 7 Lead Free Accounting For The Reduced Sample Size We must now increase this value by 1 124 to compensate for the fact that we are only using 18 parts instead of 23 parts see appendix B for calculations Final Number of Thermal Shock Cycles 283 03 1 124 318 24 Cycles gt PTC Step 8 Lead Free Applying The Coffin M
134. 99 GENERAL MOTORS CORPORATION EDSON 2008 64 WEIBULL ANALYSIS Referring to the type of analysis of data obtained from testing a group of products to failure Waloddi Weibull Swedish was the engineer responsible for the statistical distribution that bears his name Weibull plotting of failure data displays the cumulative failures on log of the log by log paper Special graph paper and software is available for performing this analysis Moving From a PDF to a CDF Weibull CDF 1 00 4 4 4 4 4 4 4 4 4 4 44 L 99 eibull Weibull Weibull Data 1 PDF CDF Probability Density Function Unreliability vs Time Plot Larry Edson Cons 7 6 2004 09 54 120 00 180 00 240 00 300 00 0 40 00 80 00 120 00 160 00 200 00 1 00 10 00 100 00 Cumulative Density But The Y Scale Is Double Logged Function Log of the Log Probability Cumulative Density Function
135. A Mismatch In The Coefficient Of Thermal Expansion CTE Fundamental Rule A high level of stress may be produced under conditions of changing temperature when materials with different CTE values are bonded together without some form of compliance mechanism Coefficient of Thermal Expansion CTE is an important consideration for electrical systems and mechanical system The strain equation for CTE mismatch is as follows Note L is the longest distance of mutually confined length Solutions Use materials with similar CTE values a Provide a compliance mechanism to accommodate the relative change in dimensions The effect expansion and contraction occurring over and over again produces fatigue in the connection points The following graphic shows the stress and strain resulting from changes in temperature GENERAL MOTORS CORPORATION EDSON 2008 32 Thermal Fatigue Stress On Solder From CTE Mismatch Small Movement __ Legend Leaded Solder Lead Free Solder Stress ia Large Movement Compression Temp Elastic Plastic amp Creep Energy Time Repetitive Thermal Cycles gt The following graphic shows how creep damage in solder will continue to occur all the way down to 40 of the melting point of the solder in degrees Kelvin How Much Dwell During Thermal Cycling Leaded Max Damage Possible Note Homologous Temperature Consideration A
136. ALYSIS The analysis of resonant frequencies can be performed with simple calculations as shown in the book Vibration Analysis For Electronic Equipment by David Steinberg reference 1 This analysis can also be performed using Finite Element Analysis FEA The resonant frequency analysis will allow the designer to know if a circuit board is insufficiently Supported given the mass that is attached to the circuit board and the overall size of the circuit board The circuit board should have a resonant frequency greater than 150 Hz A circuit board with a high resonant frequency will have a small displacement during resonance A circuit board with a low resonant frequency will have a large displacement during resonance Large displacements of the circuit board result in higher stress levels to the components that are attached to the circuit board The high stress with vibration will result in fatigue failures The above discussion may also apply to other critical elements other than a circuit board Purpose This analysis is to be performed for devices with internal printed circuit boards Structural dynamic modal analysis is performed to determine the fundamental frequency of the circuit board and the resulting maximum board displacement Low resonant frequencies and the resulting high displacement will cause excessive fatigue damage to interconnect wires and junctions on the circuit board Locations of Applicab
137. AMP Tyco Electronics Corp Tin or tin alloy coatings are cost effective and reliable alternatives to gold if used according to the following guidelines 1 Tin coated contacts should be mechanically stable in the mated condition 2 Tin coated contacts need at least 100 grams 3 53 ounces of contact normal force Higher forces are desirable whenever possible 3 coated contacts need lubrication 4 coating is not recommended for continuous service at high temperatures At elevated temperatures electrical contacts degraded by the aging effects of the diffusion of copper and tin It is recommended to use a nickel underlayer to prevent the brittle non uniform resistive layer of the copper tin intermetallic compound 5 choice of plated reflowed hot air leveled or hot tin dipped coatings does not strongly affect the electrical performance of tin or tin alloy coated contacts 6 Electroplated tin coatings should be at least 100 micro inches thick 7 Mating tin coated contacts to gold coated contacts is not recommended 8 Sliding or wiping action during contact engagement is recommended with tin coated contacts 9 Tin coated contacts should not be used to make or break current 10 coated contacts can be used under dry circuit or low level conditions GENERAL MOTORS CORPORATION EDSON 2008 GOLDEN RULES GUIDELINES FOR THE USE GOLD ON CONNECTOR CONTACTS The followin
138. And IEC International Electro Validation Technical Commission AFD Anticipatory Failure IP International Protection Determination Input Output m ES Rated Current Of Protection 25 Number Of Lives C Statistical Confidence Tested CAN Controller Area Network Fatigue Exponent Slope Of 25 Technical The S N Line Specification Not Applicable DRBFM Design Review By Failure Power Temperature Cycles M T oe Product Validation DRBTR Design Review By Test Results DUT Device Under Test DV Validation Classification Gn Standard Acceleration Of Alternator Operating Free Fall Gravitational Test Voltage Representing Constant 9 80665 M S Alternator Not Operating HALT Highly Accelerated Life Test 17 GENERAL MOTORS CORPORATION EDSON 2008 Special Unit Conversions Used In This Document 1000 aches 1 megahurtz Basic unit of laryngitis 1 hoarsepower Ratio of an igloo s circumference to its Shortest distance between two jokes diameter Eskimo Pi A straight line 2000 pounds of Chinese soup Won ton 453 6 graham crackers 1 pound cake 1 millionth of a mouthwash 1 1 million million microphones 1 microscope megaphone Time between slipping on a peel and smacking the pavement 1 1 million bicycles 2 megacycles bananosecond Weight an evangelist carries with God 365 25 days 1 unicycle 1 billigram Time it takes to sail 220 yards at 1 16 5 feet in the Twilight Zone 1 Rod n
139. Awake illi 220 gp 200 Milliamps ran c uae 150 Milliamps 2 b Off Asleep a Two Minutes Remainder of Time Until The Ignition Is Turned Back On Ignition Time Ignition Off On During the time the module is off awake it draws 200 mA When in the off asleep state the module draws 150 mA Both current ratings apply at 25 and 12 volts The answer sought in this example is What is the average parasitic current draw over the 40 day period 195 GENERAL MOTORS CORPORATION EDSON 2008 Answer Parasitic current is equal to Current when orae Tunes oT awake minutes in 40 days minutes in 40 days 2 57600 2 iti 200mA x 150mA x Parasitic current 57600 0 157 mA when off asleep x Complex Example Average Parasitic Current Calculation This test is only to define the parasitic loss from expected operations Other devices may unknowingly wakeup this device but that fact is not to be included in this test process An ECU is turned OFF and wakeup events follow the schedule shown below e hour after the OFF power mode the ECU is powered for 1 minute e 24 hours after the OFF power mode the ECU is powered for 1 minute e 5 days after the OFF power mode the ECU is powered for 1 minute e 2 weeks after the OFF power mode the ECU is powered for 1 minute 4 weeks after the OFF power mode the ECU is powered for 1 minute e 6 weeks after the OFF po
140. CK AND POWER TBMPERATURBECYCLE TE STINO co o Eie Eoi oodd 202 APPENDIX H VALUES FOR M IN THE COFFIN MANSON 299 APPENDIX I GUIDELINES FOR VIBRATION TESTING WITH A REDUCED SAMPLE SIZE 300 APPENDIX J GUIDELINES FOR HIGH TEMPERATURE DURABILITY TESTING 303 APPENDIX ACCELERATED HUMIDITY 4 422242 101 100 06 0030000 304 APPENDIX L RELATIONSHIP OF RELIABILITY ON TEST TO RELIABILITY IN THE FIELD AND DESIGN MARGINS usus ud de 305 APPENDIX M PLASTIC SNAPFIT DESIGN WORKSHEET eene 307 APPENDIX N HARDWARE SOFTWARE FUNCTIONAL ROBUSTNESS TESTING 314 APPENDIX DESIGNING BRACKET WITH ADEQUATE FATIGUE LIFE 318 REFERENCES GENERAL MOTORS CORPORATION EDSON 2008 HOW TO USE THIS DOCUMENT This document was written to assist the engineering community in the proper use and interpretation of GMW3172 In any situation where there may appear to be a difference between this handbook and the most recent official specification the official specification will always take precedence over this handbook Let s begin with a basic understanding of the concept of ADV ADV stands for Analysis Development and Validation and describes the sequence of activities that should occur during product dev
141. Dr Seuss On Beyond Zebra And he worries each day from GENERAL MOTORS CORPORATION EDSON 2008 300 Appendix J Guidelines For High Temperature Durability Testing Running the test at a temperature higher than Tmax can reduce the test time of 500 h or 2000 h for the high temperature durability test The test acceleration factor TAF can be determined from the Arrhenius relationship Equation 10 Arrhenius Equation For Accelerated Temperature Testing TAF exp x E k 273 273 1 k Boltsmann s Constant 1 380 658 0 000 012 x 1023 J K Where Ea Average Conservative Activation Energy 1 28 x 10 J 0 8 eV Example 1 For Tmax 85 C and a test time of 500 hours Ttest 105 C for fewer hours 1 28 107 1 1 500 39 127 hours zii 38x10 2 I 85 273 tus 75 94 test time be reduced from 500 h to 127 h if the temperature is increased from 85 C to 105 C If this method is used the supplier is responsible for documenting the source of the activation energy Example 2 For Tmax 125 and a test time of 2000 hours Tres 140 C for fewer hours 1 28 107 1 1 7 2000 848 hours ara zia 25 75 36 The test time can be reduced from 2000 hours to 848 hours if the temperature is increased from 125 to 140 If this method is used the supplier is responsible for documenting the source of the activa
142. G VIBRATION PROFILE cccsccssccssccssccssccssccsscevscesceescescesscesscesscesccescescesscesscesscs 268 TABLE 35 MEDIAN RANKS FOR WEIBULL 44 4 4 000000000 280 TABLE 36 FEST TO FIELD CORRELATION VALUES sssssseesesssesecssossresrsenessecsecososecssessnesnessecoresecsscsssssneses 306 TABLE DESIGN MARGIN GUIDELINES E ENEKO 306 Table of Figures PIN A a 57 FIGURE 2 CHIP ON BOARD CONSTRUCTION aa 58 FIGURE 3 COMPLIANT PIN CONSTRUCTION 59 FIGURE 4 GRAPHICS OF THE CROSS SECTION OF PLATED THROUGH HOLE OR VIA 60 FIGURE 5 CROSS SECTION OF A PLATED THROUGH HOLE 0 0 111 1000 00 61 FIGURE 6 CRACKS IN THE WALLS OF THE PLATED THROUGH HOLE eee eene 61 FIGURE 7 SUDDEN DEATH TESTING EXPLAINED 222425 voe b n se RE c9 PLE e o Pe FERE V FEE deese pU dia vepres iU p ux 69 FIGURE 8 CALI ESTING EXPLAINED I I 70 FIGURE 9 DEGRADATION ANALYSIS EXPLAINED at eua aie ma oua s memos Uu pomo 71 FIGURE 10 CODE LETTER SEQUENCE 2 0000000000000000000000 124 FIGURE 11 PROCESS FLOW FOR ELECTRICAL COMPONENT VALIDATION
143. July 2008 Our push on Lead solder will begin in July 2008 and is expected to finish in July 2010 Any questions on the elimination of these chemicals can be directed to Doris L Hill Ben Tactical strategy for lead elimination in electrical electronics We have stated a requirement for lead free starting in 2009 model year in order to set expectations within the supply base We intend to carry over reuse components without material change redesign revalidation as long as feasible Any new component design cycles must be designed with lead free processes Questions on lead free specifics or strategies can be directed to Benjamin H Baker The following boxed words are those appearing in GMW3059 This material specification represents the enforcer in the move to lead free solder GENERAL MOTORS CORPORATION EDSON 2008 General Motors is working to eliminate Lead from electrical and electronic assemblies beginning with 2009 model year vehicles Lead in Electronics Will be Prohibited in solder and component finishes used in electrical and electronic components for all parts to be released the first time for vehicle lines as of MY 2009 onwards and for powertrain units safety applications and applications requiring additional technical maturity as of MY 2012 onwards Long term carryover components may continue to use lead after 2012 until the device is resourced or redesigned at which time they must become lead free This lead
144. Locations of Applicability This test is applicable to all devices attached to the body or frame of the car or truck Procedure Monitoring Constant monitoring is required during the entire test to detect intermittent failures Operating Type The test shall be performed under operating type 3 2 Use test methods according ISO 16750 3 Test IV Passenger car sprung masses vehicle body During vibration load testing the DUT shall be simultaneously subjected to temperature cycles according to the vibration test temperature cycle The DUT shall be electrically operated and continuously monitored while on test Cars Test duration 8h for a sample of 23 parts for each X Y and Z coordinate axis perpendicular to the plane of the circuit board of the DUT for a base requirement of 100 000 to 200 000 miles This test duration may need to be adjusted to offset a reduced sample size Trucks Test duration 18h for a sample of 23 parts for each X Y and Z coordinate axis perpendicular to the plane of the circuit board of the DUT for a base requirement of 100 000 to 200 000 miles This test duration may need to be adjusted to offset a reduced sample size Note Devices that always located in consistent areas of the vehicle like clusters and radios may receive a custom vibration test developed using the process described for brackets GENERAL MOTORS CORPORATION EDSON 2008 Figure 33 Random Vibra
145. M controlled loads Conditions of special interest would include situations where current consumption can be very low for some operating conditions or very high due to input LC filter energy storage or output LC filter resonance Locations of Applicability All devices in any location that may be effected by a normal level of A C ripple on the 12 volt wiring system Procedure Monitoring Continuous monitoring is required to detect intermittent faults Operating Type The test shall be performed under operating type 3 2 Connect the DUT to the Uo output Follow the given sequence lo output current capability 50A Rise time lt 10us for a 2V step 22 RC 3 18ms 50 Hz f_low Load_1 Vs 9 OG h Load_n Pg Uo Us Up Us Vmin 2V to 14 V DC voltage Start at Us 14V Up Square wave 1 0V to 1 0V 50 duty cycle 2 0Vp p Up frequency sweep range 1 Hz to 4 kHz Frequency sweep type Logarithmic Sweep duration for one cycle 120s for 1 Hz to 4 kHz to 1Hz Number of sweeps 5 continuously After each five complete frequency sweeps decrease Us by 1 0 V Repeat until Us 2V Vmin At room temperature TRT at Tmin and at Tmax repeat this sequence For DUT s with power output drivers the test shall be performed with real loads connec
146. MW3172 have been calibrated to produce the same level of material loss seen in electrical products retrieved from the junkyards of Nova Scotia Spray Test GMW3172 has been calibrated against 10 years of field usage for underhood mounted engine controllers duration of the corrosion tests in GMW3172 have also been benchmarked against the work of Dr Bo Carlsson of the Swedish Testing Institute in his paper Accelerated Corrosion Test For Electronics Dr Carlsson s corrosion test for electronics is becoming an ISO specification Why did you write this User s Guide Handbook when we already have the specification technical depth and widespread usage of GMW3172 has demanded that the engineering community be provided a complete understanding in the use of this document The constraints of specification structure and formatting prevent the Opportunity to provide adequate explanations for complete understanding and efficient usage GM Specification Department suggested that a User s Manual would be an acceptable solution toward providing all necessary information What specification should I use if I have a smart switch do I use GMW3172 or do I use GMW3431 GENERAL MOTORS CORPORATION EDSON 2008 12 You will need to use a composite of both specifications Most of the environmental tests defined in GMW3431 direct the user to GMW3172 An example Smart Switch Test Flow appears in this document Wh
147. Mode Mode 2 1 24 1 Hours 2 Minutes Hours Criteria Functional status shall be class A HIGH TEMPERATURE DURABILITY The High Temperature Durability Test exercises the stresses resulting from diffusion effects in materials and from thermal degradation The duration of this test is empirically derived and we are also using this test as a pre treatment test prior to mechanical shock to detect possible Kirkendall voiding failures when lead free constructions are used The effect of the post heat temperature identified as Tmax PH is comprehended in this test with 5 of the test duration occurring at the Tmax pu temperature level The one hour time at Timax pps is used to evaluate the effects of storage temperate and evaluate the ability of the device to withstand the thermal stress of paint booth reheating Testing at the Tinax rps temperature may reveal possible warpage effects plastic as molding stresses relieved annealing One life of duty cycle should occur during this test and this should be used to compensate for times when one life of duty cycles cannot be GENERAL MOTORS CORPORATION EDSON 2008 238 239 applied during PTC testing Degradation of performance between the beginning and the end of this test should be evaluated This test may be accelerated using the Arrhenius equation in Appendix H providing the foolish limit for materials is not exceeded Purpose To
148. Mt Evans in Colorado GENERAL MOTORS CORPORATION EDSON 2008 164 165 Is there adequate design margin for high temperature operation considering the device itself and the components and materials in the area around the device The device reaches stabilized temperature of 5O degrees in Michigan while operating ambient temperature of 23 degrees I ambient x Multiplier T attitude 7 level P level ambient ltitude 2 23 50 23 x1 33 50 23 x1 33 23 59 degrees In this example we know that the device and all surrounding materials will show no degradation up to 75 C Given that the device will only reach 59 no problems from overheating should be expected at high altitude Purpose High altitude analysis is to be performed on all E E devices that contain significant heat generating elements on their circuit board and are cooled by convection The reduced air density at high altitude will reduce convective heat transfer and may cause marginal designs to overheat while operating within the vehicle This analysis is used to determine if the DUT will suffer from overheating when operating the vehicle at a high altitude up to 4572 meters 15 000 feet above sea level Locations of Applicability Applicable primarily to areas inside the passenger luggage area where it is warm External temperatures at altitudes are generally cold and overheating
149. N FACTOR 0 000000000000 5 285 EQUATION 5 LEADED SOLDER ACCELERATION 6 1 0 293 EQUATION 6 MULTIPLE LIFE TESTING WHEN USING A REDUCED SAMPLE SIZE cene 300 EQUATION 7 ACCELERATED VIBRATION STRESS LIFE 300 EQUATION 8 ADJUSTMENT FACTOR FOR SCALING PSD TO 5 301 EQUATION 9 ELECTRO DYNAMIC SHAKER TABLE DISPLACEMENT 302 EQUATION 10 ARRHENIUS EQUATION FOR ACCELERATED TEMPERATURE TESTING 303 EQUATION 11 ARRHENIUS PECK ACCELERATION FACTOR FOR TEMPERATURE AND HUMIDITY 304 Appendices APPENDIX A GMW 3172 TEST PLAN 274 APPENDIX RELIABILITY DESIGN 5 6 275 GENERAL MOTORS CORPORATION EDSON 2008 APPENDIX C SUCCESS RUN 5 5 5 277 APPENDIX D WEIBULL ANALYSIS AS APPLIED TO VIBRATION TEST TO FAILURE 278 APPENDIX E LEAD FREE SOLDER CONSIDERATIONS eene 281 APPENDIX F LEAD FREE SOLDER GUIDELINES FOR THERMAL SHOCK TESTING AND POWER TEMPERATURE CYCLE FESTING iiiete irre eot eee en uinea nta 284 APPENDIX G LEADED SOLDER GUIDELINES FOR THERMAL SHO
150. NERAL MOTORS CORPORATION EDSON 2008 312 Procedure Criteria 1 With the device operating in a normal condition disable the SOH stimulation signal from the interrupt triggered event Monitor the supervisor circuit and the system to verify that the loss of the SOH signal results in an appropriate and timely system correction response signal The processor must also respond by returning to or resetting back to normal operation in a manner that prevents erratic or unstable operation of the device Verify that appropriate system diagnostic information is correctly logged updated and resetting functions are performed correctly Document the recovery time and diagnostic data for the test report and note any observation of abnormalities exhibited by the device under test NOTE A momentary orderly suspension of tasks or signals during a system reset is acceptable 2 With the device returned to normal operating condition disable the SOH stimulation signal from the main programming loop Monitor the supervisor circuit and the system to verify that the loss of the SOH signal results in an appropriate and timely system correction response signal The processor must also respond by returning to or resetting back to normal operation in a manner that prevents erratic or unstable operation of the device Verify that system appropriate diagnostic information is correctly logged updated and resetting functions are performed correctly Document
151. ONS The following tables are provided to help in the planning of total test duration Test leg 6 is not shown as these are short duration tests that do not need to occur in any specific sequence Timing assumes an 8 hour work day or 24 hour days for thermal chambers The sample sizes used are those shown in the test flows LEADED SOLDER Interior Module Leaded Solder Table 10a Tables 10 a b c d e Leaded Solder Test Duration In Days By Test Leg Initial Initial Initial Initial Initial Initial Room Temp Temp Temp Temp uaa Volts Volts p p p Unom Volts Para Volts Volts Volts Volts Para pale Eval Para Eval Para Eval Para Eval Eval Eval p Eval 500 Hr 100 G Moisture 25 G Mech Thermal Salt High Mech Suscepti Shocks Shock Corrosion Temp EE bilit Optional 0 2 Fretting Closure Corrosion Slam Test Cyclic Or IP Code ISO 8820 i Over Constant Testing Humidity Dust Vibration Detection With Vibration IP Code Testing Thermal with i Water Thermal Post Temp Temp Volts Para Volts Eval Para Eval 155 GENERAL MOTORS CORPORATION EDSON 2008 Initial Temp Volts Para Eval 2000 Hr High Temp Volts Para Eval Initial Temp Volts Para 2000 Hr Temp Underhood Module Leaded Table 10b Initial Temp Volts Para Eval Mech Volts Para Eval Initial Temp Volts Para 100 G Mech Shock 100 Shock Initial Te
152. ORS CORPORATION EDSON 2008 Why Focus Failure Mechanisms Failure mechanisms are the root cause of failure modes Failure mechanisms are limited in number and can easily addressed Years of cumulative engineering knowledge of failure mechanisms 15 available and can be applied across all products and all industries not product specific comprehensive understanding of failure mechanisms is fundamental in effectively using the tools Design Review Based on Failure Mode DRBFM and Design Review Based on Test Results DRBTR Good test flow design is based upon an understanding of failure mechanisms and their interactions We divide failure mechanisms into two major categories those that are considered an Overstress where a single occurrence produces failure and those that require Cumulative Damage to produce failure The manifestation of either type of failure mechanism is a failure mode While there are only handful of failure mechanisms there are millions of failure modes An example of a failure mode would be that the part cracked at the bend in the metal as a result of the failure mechanism of vibration fatigue Focusing on the mechanisms of failure allows us to tackle the root of the reliability problem Cumulative damage failure mechanisms often require a long duration of time for testing or to produce failures Validation Engineers apply accelerated testing to these cumulative damage failure mech
153. Only dd 99 GENERAL MOTORS CORPORATION EDSON 2008 CODE LETTER FOR ELECTRICAL LOADS The device must operate over a range of possible voltages The code shown below defines that range The notation is referencing voltage as applied to the device the test setup Adjustments in Umax can be made for Regulated Voltage Control given adequate knowledge of how RVC is operating for this device The car will most likely start when there is 11 or more volts on the lines Codes A and B are used when there is a safety concern to ensure that a product like the fuel pump would always be ready to operate even if the engine would not start The following table defines the steady state minimum and maximum test voltages to be used as measured at the connector of E E device The table Should also be used in specifying the E E device criteria requirements unless otherwise specified in the CTS Table 2 Code Letter for Electrical Loads Code Cis Voltage Range in Volts Code Letter Umn 1 45 J J 16 9 6 1 16 16 C most common e Inthe range of the given code letter the Functional Status Classification shall be class A e In the voltage range of 13 5 Volts to Umi and Umax to 26 Volts the Functional Status Classification shall be at minimum class C GENERAL MOTORS CORPORATION EDSON 2008 100 Nominal Voltage Unom nominal voltag
154. Procedure Monitoring Continuous monitoring is required to detect overheating and proper return to function Operating Type The test shall be performed under operating type 3 2 Use the test methods in accordance with ISO 16750 2 Single Line Interruption Criteria Functional status should at minimum class C Open Circuit Signal Line Multiple Interruption Purpose Determine if the device is able to suffer no damage due to incomplete contact conditions and to determine if the part functions properly immediately after the completion of the contacts Locations of Applicability All locations Procedure Monitoring Continuous monitoring is required to detect overheating and proper return to function Operating Type The test shall be performed under operating type 3 2 Use the test methods in accordance with ISO 16750 2 Multiple Line Interruption Criteria Functional status should at minimum class C Open Circuit Battery Line Interruption Purpose Determine if the device is able to suffer no damage due to incomplete contact conditions and to determine if the part functions properly immediately after the completion of the contacts GENERAL MOTORS CORPORATION EDSON 2008 204 205 Locations of Applicability All location but only devices that have connections to the 12 volt wiring system Procedure Monitoring Continuous monitoring is requi
155. Rev 18 Dec Many changes made for clarification including new 2007 diagrams and procedures Rev 19 Feb Addition of Pulse Superimposed Alternating Voltage 2008 Within Normal Levels Test Significant changes in mechanical shock testing and corrosion testing with additional clarification provided in many other tests Restructured to focus more on the ADV sequence reat spirits have always encountered violent opposition from mediocre mind s Albert Einstein 1879 1955 271 GENERAL MOTORS CORPORATION EDSON 2008 Appendix A GMW 3172 Test Plan Template GM WORLDWIDE ENGINEERING STANDARDS GMW 3172 Test Plan Template GMW 3172 Test Plan Template Devis Under Test ne abbreviations Hevisien Dale Revision Nr TAD TED CUT Humbera DUT HManulacthurer TAD Drawing Humber Prepared by supplier Mounting Location in Approved by Supplier Approved by vehicle manufacturers rey Revision Harary Revision Mr Description This ts approved with the following corrections andor added GM WORLDWIDE ENGINEERING STANDARDS GMW 3172 Test Plan Tamplate 1 The Environmental Component Test Plan TP shall be by ihe supplier and submitted manufacturers Emvdranmental Design Reve Team members for appraval in ire wilh the M
156. Shall be functionally cycled during the 85 C portion of the test sequence The functional cycle and the number of cycles shall be individually specified in the relevant component specification on the component drawing Requirements of functional status A shall be met GENERAL MOTORS CORPORATION EDSON 2008 Criteria The requirements of functional status A shall be met throughout the test HIGHLY ACCELERATED STRESS TEST HAST FOR HUMIDITY This is extremely accelerated humidity test and can be Quantitative in nature per the Arrhenius Peck equation defined in Appendix I Use this test where circuit board in unsealed enclosure will be used in a humidity severe environment The HAST Chamber will only operate above 106 C Low temperature plastics will melt when placed this chamber HAST testing should be reserved for high temperature products or circuit boards Purpose 5 9 Highly Accelerated Stress Testing employs increased temperature and pressure to elevate the vapor pressure of non condensing high humidity environment Locations of Applicability Severe areas of heat and humidity where there is uncertainty as to the GENERAL MOTORS CORPORATION effectiveness of the protection from the housing Procedure Monitoring The DUT parasitic current is monitored continuously during the time that the DUT is energized on test Operating Type The test shall be performe
157. Sn SnCu Bright Tin with Nickel Underplate Bright Tin 1 d Ag over Ni AgPd over Ni Ag Category 1 No tin whisker testing required Category 2 Finish must pass tin whisker testing Category 3 Do not accept this finish in any case Color Coding for Table 1 Green Preferred finishes Blue Finishes with preferred tin whisker mitigation practices Finishes with tin mitigation practices that are less desirable than preferred practices Lm Finishes without tin whisker mitigation that are often not acceptable to users Yellow Finishes to avoid The following chart from iNEMI provides a similar set of recommendations for separable connectors Again those at the top of the chart are of least risk GENERAL MOTORS CORPORATION EDSON 2008 while those at the bottom of the chart represent the greatest risk for tin whisker formation INEMI ratings for whisker risk on termination finishes for separable connectors Finish Termination finish Terminal finish use Terminal finish use use only as a as a separable as a separable solderable finish interface for fine interface for large spacing applications spacing applications i 1 NiPdAu 1 Green Az over Hot Dipped 7T A ReflowedSn ed Sn Hot Dipped Sn J Blue b I bo Sa Wi 7 Nickel underplate Matte So w Silver underplate Matte Sn 150C anneal Matte SnB1 2 4 wi Nic
158. Summary of Salt Corrosion Testing of The Total Test Location Passenger Compartment 72 240 Salt Mist Door Interior 480 Salt Spray Engine Compartment High Mount or Exterior High p 480 960 Mount Salt Spray Underbody Salt Spray ENCLOSURES TESTS The Tests for Enclosures encompasses the dust test and the water tests These tests can be as important for interior locations as they are for exterior locations DUST Purpose To determine if the enclosure provides sufficient protection from dust intrusion from windblown sand and road dust to allow the DUT to continue to meet the performance requirements specified in the CTS The accumulation of dust on heat sink devices will adversely affect heat dissipation Dust may also combine with humidity and salt to produce unintentional conductive paths Dust accumulation will adversely affect electro mechanical devices resulting in increased friction or complete blockage of motion Locations of Applicability This test is applicable to all areas of the vehicle Procedure Monitoring The DUT is not energized or monitored during the application of dust The DUT is evaluated following the dust test and monitoring should occur during this evaluation Operating Type The operating type shall be 1 2 during the time that the device is being dust tested The operating type shall be 3 2 during the post evaluation Test according to IEC 60529 1
159. TIC LONABD S eene prag Inu eges aU 107 TABLE 6 CODE LETTER FOR CHEMICAL LOADS 110 2 116 TABLE 8 SUMMARY OF FSC AND OPERATING 117 TABLE 9 CELSIUS TO FAHRENHEIT CONVERSION cssccssccsscssccsccssccsscesscesscevscescesscesscesscesscescesscenss 120 TABLES 10 A B C D E LEADED SOLDER TEST DURATION IN DAYS BY TEST 137 TABLE 11 A B C D E LEAD FREE SOLDER TEST DURATION IN DAYS TEST LEG 140 TABLE 12 JUMP START 0 me een ee ee etn 175 TABLE 13 REVERSE POLARITY 176 TABLE FOV OLTAR LE T a MM IDEM UM E EP IM 177 TABLE 15 MECHANICAL SHOCK TESTS BY AREA OF VEHICLE AND BY TYPE OF VEHICLE 189 TABLE 16 QUANTITY OF MECHANICAL SHOCKS FOR CLOSURES eese eene enne eene 191 GENERAL MOTORS CORPORATION EDSON 2008 TABLE 17 SLAM BASED MECHANICAL SHOCK 5 00000000000000 0 teretes eara 191 TABLE 18 DESCRIPTION OF ONE 24 HOUR MOISTURE SUSCEPTIBILITY TEST 193 TABLE 19 BATTERY VOLTAGE DROPOUT TEST DURATIONS cccccssccssccssccssccsccesc
160. TORS AND BALL GRID ARRAYS Ceramic chip capacitors are small devices that are frequently surface mounted onto circuit boards The ceramic material is brittle and cannot withstand bending stresses Bending stresses result from separation of one board from another during manufacturing depaneling testing general handling connector attachment free fall or significant levels of mechanical shock as mounted in the vehicle Placing these capacitors in a location and orientation where flexing can be damaging is one the most common mistakes made in electronic design following best practice design rules will minimize the risk from this phenomenon Control all board bending events during manufacturing Use capacitors with a flexible termination Keep the capacitor away from the edge or point of flexure Orient the capacitor such that the natural bending action of the board does not apply stress along the longest axis of the capacitor Longer capacitors are more at risk than shorter capacitors This problem expands to include ball grid arrays BGA devices especially when using the stiffer lead free solder Cracking can occur in the BGA laminate solder ball or within the printed circuit board when a BGA device experiences flexure stress from circuit board bending ANISOTROPIC CONDUCTIVE FILM ACF ACF is an adhesive that contains fine particles of silver or nickel to form a connection between two conductor pads in the Z direction Co
161. Temp Volts Para Shock High Temp Shock Corrosion 4 Optional Cyclic Or Shock Constant Closure Humidity Slam Test Vibration Detection With Vibration Thermal with Thermal Post Temp Volts Para Eval Volts Para Eval Initial Temp Volts Para Eval IP Code Testing Dust Testing Water Post Temp Volts Para Eval Initial Temp Volts Para Eval Moisture o Suscepti Humidity 0 bilit ISO 8820 Over Current GENERAL MOTORS CORPORATION EDSON 2008 GMW3172 A D V TASK CHECKLISTS This is the list of all of the things that potentially should be done You must review this list with the supplier and the DRE at the beginning of a program to make sure that everyone knows exactly what is expected and what can be deemed un necessary Fill in the This Program column and use this as input for the ADVP amp R form GM 1829 form Definition of Recommendations Want Mandatory for electronic modules Mandatory when condition or design feature exists Recommended shall be conducted but may be waived only by GM under special circumstances Recommended activities becomes Mandatory when so identified by General Motors Conditional task based on presence of feature technology risk or vehicle location Procedure Want This Program Analytical Tasks Electrical Analysis Nominal and Worst Case Performance Simulation Short Open Circuit Analysis Lead Free Solder Checkli
162. Tests CONTINUOUS SHORT CIRCUIT Purpose This test is required for short circuit protection output types that are specified to be protected by means of electronic current limiting Locations of Applicability All Procedure Monitoring Proper function is not expected during shorting Monitor for overheating and for return of proper function at end of test Operating Type The test shall be performed under operating type 3 2 loads on 1 Raise and stabilize the chamber temperature to Tmax 2 Apply Umax to the DUT 3 Apply an 8 h continuous short circuit condition 4 Remove the short circuit condition and perform all required recycle reset and cool down conditions and confirm the correct operation of the outputs with normal loads 5 Lower and stabilize the chamber temperature to Tmin 6 Apply and 8 h continuous short circuit condition to the previously tested outputs 7 Remove the short circuit condition and perform all required recycle reset and cool down conditions Criteria Functional Status shall be class C The external short circuit fault shall not prevent any other interface from meeting requirements It is also required that the tested outputs be included in parametric measurements These measurements shall be capable of detecting potential output degradation such as unacceptable current draw voltage drop changes GROUND INTERCONNECT SHORT TO BATTERY Purpose T
163. This test specifies the procedure for testing the immunity of E E devices to positive over voltage Locations of Applicability Applicable to all devices in the vehicle that have connection to the 12 volt wiring system Procedure Monitoring After the test during final evaluation Operating Type The test shall be performed under both operating types 3 1 loads off and again under 3 2 loads on Use the test method according 15016750 2 Over Voltage with the exceptions shown in table 12 Table 12 Jump Start Requirement Test Time min Test Voltage V Criteria Functional status should at minimum class C All functions needed to start the engine must be available at the test voltage if not stated differently in the CTS REVERSE POLARITY The Reverse Polarity Test recreates the condition when the customer or a service technician accidentally connects the battery terminals reverse polarity Electronic devices throughout the vehicle should not be destroyed because of the application of reversed battery polarity Devices that include a motor with a diode across the inputs designed to prevent transient problems should receive special attention when this test is administered The diode should be removed from the system because this test will destroy that diode GENERAL MOTORS CORPORATION EDSON 2008 Purpose This test specifies the procedure for testing the immunity of E E devi
164. a lt lt lt UJ UJ UJ UJ NINININ V 3 2 Electrical Centers 1 1 1 1 1 1 3 2 11 GENERAL MOTORS CORPORATION EDSON 2008 Test Title Phase Vibration With Thermal Cycling V Evaluation Of Squeaks and Rattle BE Operating Type 21 3 2 gt Following Vibration With Thermal Cycling FreFal 4JJOD 0 0 V Low Temperature Wakeup im lt 2 gt NIN m 22 J UJ UJ NIN n Seal Evaluation Vibration Shipping 2 1 an 1 2 an 1 2 an 1 2 an 1 2 an Ae 1 1 OININIR Q Q e Q Q OJ GI UJ UI OU NINININININ UJ Table 9 Celsius To Fahrenheit Conversion 99 146 2 1 33 8 101 213 8 201 393 8 301 573 8 98 144 4 2 35 6 102 215 6 202 395 6 302 575 6 97 142 6 3 37 4 103 217 4 203 397 4 303 577 4 96 140 8 4 39 2 104 219 2 204 399 2 304 5 9 2 95 139 0 5 41 0 105 221 0 205 401 0 305 581 0 94 137 2 6 42 8 106 222 8 206 402 8 306 582 8 93 135 4 7 44 6 107 224 6 207 404 6 307 584 6 92 133 6 8 46 4 108 226 4 208 406 4 308 586 4 91 131 8 9 48 2 109 228 2 209 408 2 309 588 2 90 130 0 10 50 0 110 230 0 210 410 0 310 590 0 89 128 2 11 51 8 111 231 8 211 411 8 311 591 8 88 126 4 12 53 6 112 233 6 212 413 6 312 593 6 87 124 6 13 55 4 113 235 4 213 415 4 313 595 4 86 122 8 14 57 2 114 237 2 214 417 2 314 597 2 85
165. a RRX S 8 00E 3 Density Function F 100 S 0 6 00E 3 My Distribution Will Accommodate All Shapes And All 4 00E 3 2 00E 3 Weibull Shape 63 Parameter i 0 60 00 120 00 180 00 240 00 300 00 Characteristic Life Hours On Test Until Failure B 2 01 n 89 74 MEDIAN RANKS The Median Rank Values are used to define the Y axis plotting position for data plotted on Weibull Paper The time to failure value is used as the X axis plotting position GENERAL MOTORS CORPORATION EDSON 2008 66 67 RANK ORDER t RANK ORDER 4 10 12 13 14 15 16 17 18 19 20 1 2 50 000 29 289 202630 MR 11 6 9107 14 796 234578 32 380 41 2189 50 000 585811 672620 762421 854 204 93 893 j 3 N44 702711 50 000 79 370 100 12 13 5 192 122579 202045 27 528 35 016 422508 50 000 57 492 64 984 72 4572 792955 874421 94 808 52613 13 598 212669 294758 37 853 45 951 54 049 622147 70 2 2 78 331 86 402 94 387 MEDIAN RANKS SAMPLE SIZE 4 15910 38 573 61 427 84 090 5 12 4945 31 2381 50 000 685619 87 055 6 104910 266545 6268141 572859 73 555 89 090
166. al specification No additional testing is required by GMW3172 Table 6 Code Letter for Chemical Loads Code letter Mounting Location for Chemical Loads A Cabin Exposed Cabin Unexposed Trunk E Under Hood Interior Door Mounted Unexposed 109 GENERAL MOTORS CORPORATION EDSON 2008 CODE LETTER FOR INTERNATIONAL PROTECTION BY ENCLOSURES The International Protection Code covers dust and water intrusion The water flow rates test setups and test durations are described in 5 20653 Dust Devices that use convective cooling heat sinks will loose their effectiveness if too much dust accumulates on the cooling structure Devices that use optics for data transfer will be degraded if dust impedes the light transmission Relays will experience degraded performance when dust is allowed to accumulate on contacts Electro mechanical devices will experience wear from dust or become inoperative if the dust accumulates preventing motion These represent the reasons that one should perform the dust test In many situations the dust test is not needed A code of X indicates that the dust test does not need be performed A code of indicates that the device does not need to be protected from dust but a dust test may be required to evaluate overheating or malfunction from contamination A code of 5K or 6K indicates that the dust test is to be run A code of indicates that dust is allowed inside and one m
167. and other failure mechanisms described in this document The Universal Durability Test Flow provided in this document effectively evaluates these interactions and Shall be used for product validation The demonstration of 97 reliability on test for a 99 8 severe user corresponds to a total field reliability of 99 5 population RELIABILITY DESIGN REVIEWS Reliability Design Reviews are the primary way in which GM Engineers can take an active role in product development In North America GM engineers do not test a sample of the product in GM labs in addition to the testing performed by supplier We must therefore rely only on the testing performed by the supplier We must have a constant interaction with the supplier to understanding that the test is properly run and to be able to properly interpret the test results Without this interaction there is little chance that we will have any impact on the product Dissection and detailed inspection of parts that have been tested is essential in keeping the engineering understanding in the Validation process Reliability design reviews are to be conducted as part of the Peer Review Process Reliability Design Review process should be structured GENERAL MOTORS CORPORATION EDSON 2008 124 to answer the questions described in Appendix A Some of Reliability Design Reviews should coincide with the Peer Review process as noted Design Revi
168. andard set of cycles in table 11 Appendices E and F are for reference During high temperature dwell During the second half of the cold temperature dwell During all transitions number of thermal cycles Power moded on 100 s and 20 s off with cycling of loads Power off Supply Voltage Only as dictated by the 20 second off portion of power moding and the first portion of the cold dwell as shown in figure 42 The test operating voltage shall be nominal for 80 low for 10 and high for 10 of the functional tests and or cycles HUMIDITY TESTS HUMID HEAT CYCLIC HHC For the HHC and the HHCO humidity tests the DUT shall be powered with a system test voltage of 11 0 V to minimize excessive localized heating of DUT components that could cause localized drying The DUT shall be functionally active but continuously locked in a steady or holding state of inputs and outputs I O and circuit activity i e statically active rather than dynamically I O exercising active The Humid Heat Cyclic Test provides two forms of stress A breathing effect of humidity is created as the temperature and humidity level is varied The 1 5 hour rapid change in temperature produces condensation on the DUT resulting in dendritic shorting GENERAL MOTORS CORPORATION EDSON 2008 250 phenomenon The Cyclic Humidity Test may be more effective on devices with seals where as the constant humidity would be more effec
169. anism that absorbs looseness should be built into this design This will prevent relative motion that creates squeaks and rattles GENERAL MOTORS CORPORATION EDSON 2008 308 309 while accommodating variation in parts The compliant mechanism is usually accomplished in one of two ways The angle of the locking ramp surface of the snap fit feature provides the compliance or a separate spring like feature is added to take up any looseness in the assembly 10 Show and explain the compliant mechanism that you have designed into this assembly to prevent squeaks and rattles Quantify how much variation your compliant mechanism is capable of handling Design The Actual Flexing Snapfit Feature The design strategy for the flexing cantilever should first address strain management and then forces The following is a good process to follow Review the equations for strain and force when a cantilever is flexed Note how some dimensions have a greater effect than others because they are Squared or cubed in the equation Establish the amount of hook engagement desired for this application Establish the length of cantilever necessary for the amount of engagement planned A good Rule of Thumb the length of the cantilever should be 8 to 10 times the length of the hook engagement for plastics similar to ABS The thickness of the cantilever is often predetermined from wall thickness When necessary walls thicker than two millimeters
170. anisms to better manage test time Accelerated testing is accomplished with a strategy that addresses one or more of the following factors 1 Larger sample size Sudden Death Testing 2 Increasing the rate of stress applications faster switch cycling is a good example 3 Selectively using only the most damaging levels of stress 4 poster testing only provides the most severe stresses while removing the non damaging low level stresses using a Rain Flow Method of analysis 4 Increasing the level of stress used frequently in this document The basic model for damage as a function of stress 15 Damage Number of Cyclesx Stress GENERAL MOTORS CORPORATION EDSON 2008 20 can see that the first three methods of accelerated testing address the Number of Cycles which has a linear relationship to damage accumulation Only the last method of Increasing the Stress Level has a leveraged non linear ability to reduce test time BASIC METAL FATIGUE Fatigue The Loss Of Strength With Usage Fatigue is a cumulative damage process that occurs with usage over time Fatigue is a localized damage process that develops with cyclic loading The following stages are typically seen leading up to a fatigue failure Crack Nucleation Time or Crack initiation period most of the life spent in this phase short Crack Growth v Crack Size gt Number of Cycles Long C
171. anson Equation To The Remaining 25 Damage Now we need to address the remaining 25 of the damage and this will be accomplished using Power Temperature Cycling PTC which permits constant monitoring Thermal shock does not permit monitoring or product activation as the parts are transported back and forth between two different chambers The PTC test keeps the parts stationary with the single thermal chamber producing a Slower rate of temperature change on the part than does thermal shock The 25 portion of the damage is as follows 7300 5475 1825 PTC Cycles GENERAL MOTORS CORPORATION EDSON 2008 286 We will use the Coffin Manson Acceleration Factor Equation to reduce the number of thermal cycles while increasing the strain with increased thermal cycling range The PTC test generates damage but is also most critical in detecting problems The product must be operated and monitored at all times during the PTC test We will use the specification level temperature requirements of 40 C to 85 C Delta T 125 C for this test because the product will be functioning and constantly monitored during the test gt PTC Step 9 Lead Free Applying The Coffin Manson Equation To The 25 Damage PTC Cycles To Reduce The Number Of Thermal Cycles With Increased Thermal Range Testing We wish to generate an equivalent degree of damage using fewer cycles but will offset the fewer cycles with greater strain using expanded thermal range testing The
172. are explained GMW8288 Products should consider this extra attention when past thermal GENERAL MOTORS CORPORATION EDSON 2008 148 This Program problems have created delays in Validation or have produced field incidents Humidity Tests Moisture Susceptibility The moisture susceptibility test is used in development when a decision needs to be made regarding the need for conformal coating iiS This test is an extremely accelerated humidity test and can only occur above 106 C HAST is only needed when there is a circuit board in a non sealed enclosure located in an area of high temperature and high humidity An unprotected circuit board located underhood would be a good candidate for this test The development tests are intended to give insight into product weakness and allow early product improvement These tests may also provide a focus for things to look for during Validation Visual inspection and dissection are a nature part of this process GMW3172 A D V TASK CHECKLIST DESIGN VALIDATION PROCEDURES Procedure This Program Functional and Dimensional Tests Temperature Voltage Functional amp Parametric pM 149 GENERAL MOTORS CORPORATION EDSON 2008 This Procedure y t 3 Dimensional Electrical Tests Parasitic Current Reverse Polarity Over Voltage Reset Behavior At Voltage Drop Battery Voltage Dropout Sinusoidal Superimposed Al
173. ass un sprung mass or engine mounted The following deviations from the standard vibration test shall apply 1 Only 24h vibration in Z axis shall be applied 2 Superimpose a Thermal Cycle Profile according the Power Temperature Cycle Test PTC Profile Three 8 hour thermal cycles shall be used per 24 hours of testing e When the DUT on test is Bussed Electrical Center 1 A durability load of 90 of generator output shall be used 2 The most critical circuits 15 to 30 shall be constantly monitored for circuit resistance These circuits Shall be predetermined through the use of analysis thermography thermal mapping with thermocouples Degradation of conductivity of each circuit of interest shall be evaluated as follows with the metric being the resistance of the circuit 1 The resistance of the circuit Shall be measured while vibration is applied at the beginning of the test 2 All subsequent resistance values shall be normalized to the original resistance with the original resistance being established as 100 multiple the original resistance Shall be determined at the end of the 24 hour vibration test while vibration is still being applied 3 Weibull analysis will performed on the six samples for each of the critical circuits Finally the Load Circuit Over Current Test shall be done with all Samples Criteria The FSC code is not applicable to this te
174. aster Timing Chart but al east 60 days prior ta lhe start ol Component testing All sadina shall ES induded as stated in the culling only addilions of new sections anre allowed section nol applicable This shall staked in the decument after the relevant section description 11 Purpose The purpose of ihe Ermiranmental Component Test Plan section documenta the OUT and lest procedures far all tests accarding GRAN 3172 I describes all rele anl test set and ihe procedures bo verily Tris environmental rebusiness of the design and production 1 2 Guidelines for Test Descriptions Pravide specific test set up intarmalian and information ihe OUT including block diagrams phalegraphs elc indicating DUT connections 1 Edity and test equipment Do nat include copies of generic set up diagram EG EO SAE ar ater standards king as you reer to documents All Does shoul be filed by supplier and be enlarged as necessary The information iride Bey box should include as much delalled information as necessary tor ihe completion of tha Test and ils Iraceabiliyrepeaiability Chapters as oven in the tamplate should stay in Tris same order Consider the Tallowire as example what be ihe content Tor the Free Fall Test Appicable ztandard GHW 3172 5 5 4 5 Operating Type 1 1 Parameters Tamperature 423 9026 C Hakght 1 maf Irae fal Concrete Proce
175. attachment requires high pressure in the Z axis to produce conduction between imbedded silver or nickel particles in the adhesive Stressed Metal micro springs provide electrical connection with adhesive used for retention high pressure not needed Si chip via N Fine pitch ClawConnect spring Adhesive LCD backplane glass Figure 1 COG packaging method using integrated springs and liquid adhesive e Cc J w M Silver or Nickel Particles Palo Alto Research Center Adhesive Anisotropic Conductive Film oi Chip Micro springs Figure 2 Schematic comparison of ACF and spring based interconnect structures PIN IN PASTE CONSTRUCTION The pin in paste PIP construction process can eliminate the need for wave soldering when through hole components are used in conjunction with surface mounted components on the same circuit board follows The basic process is as 1 A stencil is used to allow the solder paste to be selectively applied to through hole locations 2 Solder paste is forced through the stencil and into the through holes in the circuit board using a squeegee GENERAL MOTORS CORPORATION EDSON 2008 3 Through hole components are placed into the through holes VIA s in the circuit board which contain the solder paste that was deposited in the prior step 4 The temperature of the solder paste is increased past the melting point to form a
176. ature Used During Testing The maximum temperature used during testing can have a significant effect on the amount of creep that occurs during the thermal transition Creep occurs much faster at higher temperatures In this example our test temperature is equal to the maximum field temperature and the resulting acceleration factor is one 1 1 ies Highest Temperature Acceleration Factor 273 Trestmax 273 5 Highest Temperature Acceleration Factor losen sm 1 gt Step 13 Leaded Solder Total Multiplication of Acceleration Factors AT 2 5 1414 1 _ 1 Total Acceleration Factor x 768x dwell minutes x 80094x ramprate x scm iacens eaded solde field Acceleration Factor 14 41 842 97 1 11 72 Number of Cycles 155 73 11 72 gt Step 14 Leaded Solder Accounting For The Reduced Sample Size We must now increase this value by 1 124 to compensate for the fact that we are only using 18 parts instead of 23 parts see appendix B for calculations Final Number of PTC Cycles 155 73 1 124 175 Cycles The combined Thermal Shock plus Power Temperature Cycle testing should take approximately 2 22 weeks if the thermal chambers are used 24 hours per day Note A spreadsheet 15 available from Larry Edson Larry G Edson GM com which will perform all of the necessary calculations for leaded or lead free solder and will calcu
177. au T 595517 0432551 pLIE uon2essid uonoseadsu ensiA uonsedsuj ensiA pue Voy lov uonsadsu JOPO sjse 9 p euonoun JEUOI DUN pepeo sjse 2 MX IM pue aug HAA uon91C uogen gA3 350d Vo 6 M S uon edsu ensiA 2 ULYOREIGIA U L pue yeanbs 3433 sapo 4 eBeyoA 2 2 1 ajejduio 2 EU 52 53591 1 42ous 21 2 2 OOL 0 5 9 53591 euonaun J Jeguoneu48ju uona2essi pue uonaedsuj jensiA y2ous 1581 Ae1ds dh S s8 2 4 L L Mechanical Fat 183 Bung 0139 94171 1 Addy L
178. autical mile per hour Knot furlong Serling 2000 mockingbirds two kilomockingbirds Hint think Gregory 365 days of drinking low calorie beer because it s less filling 1 lite year Peck Half of a large intestine 1 semicolon 10 cards 1 decacards 1000 grams of wet socks 1 literhosen 1 kilogram of falling figs 1 Fig Newton 1 millionth of a fish 1 microfiche 8 nickels 2 paradigms 2 4 statute miles of intravenous Surgical tubing at Yale University Hospital 1 I V League The Endless Triangle GENERAL MOTORS CORPORATION EDSON 2008 18 TECHNICAL KNOWLEDGE LIBRARY The environmental tests described in this document are designed to target certain failure mechanisms that have historically created field failures in the electronics industry What s a failure mechanism A failure mechanism is the physical or chemical process that produces instantaneous or cumulative damage to the material that comprises the product Many of these failure mechanisms are treated qualitatively that is a level and duration of stress is used which has been shown to be a good discriminator between good and bad designs However this stress level and duration are not treated statistically to prove a reliability number Examples of qualitative testing include humidity dust frost salt corrosion water spray and mechanical shock In contrast the failure mechanisms of Vibration Fatigue Thermal Fatigue Fretting Corrosion Bus
179. ave a salt spray chamber but do have a salt mist chamber In this situation the Sa t Mist Test can be substituted for the salt spray test but must be run for the duration specified for the salt spray test If this substitution does occur the 3 days of ambient at the end of the test is not required SALT MIST Purpose This test is for products mounted within the passenger cabin or luggage storage area within the vehicle Salt mist test for interior devices has three functions GENERAL MOTORS CORPORATION EDSON 2008 254 e Verify functionality of the DUT following exposure to salt laden air as experienced in coastal regions e Evaluate functionality when salt water drips onto devices located in risk prone areas such as the door armrest e Evaluate the loss of parent metal that may lead to loss of connection or broken leads Locations of Applicability This test is applicable to the passenger and luggage area interior of the vehicle Test Procedure Monitoring Monitoring shall occur during the time that the device is energized Operating Type The operating type shall be 3 2 during the time that the device is energized The operating type shall be 1 2 during the time that the device is not energized Test per setup from IEC60068 2 52kb Test durations based upon IP water code per the following table Location IP Water Code Passenger or Luggage Area Passenger or Luggage Area
180. ay be destroyed through the application of this level of voltage Locations of Applicability All location Procedure Monitoring Evaluate resistance between critical elements at end of test Operating Type The test shall be performed under operating type 1 1 Use the test methods in accordance with ISO 16750 2 Insulation resistance Special Note Circuit boards with inductive loads The resistance value is the criteria of interest Less voltage lt 100 V can be used with electronic devices to prevent damage to susceptible components such as capacitors e Inductive components such as motors The resistance value is the criteria of interest A test voltage greater than 300 volts is suitable for devices such as motors This test shall be performed following a humid heat test HHCO Criteria The isolation resistance shall greater than 10 Million Q FSC is not applicable to this test PUNCTURE STRENGTH The Puncture Strength Test is only needed when more than 250 volts is present and the condition exists where this high voltage may puncture through an insulator and pose a danger to another circuit or to a human being This test will be used more often as high voltage hybrid battery packs are placed in the vehicle Purpose High voltages gt 50 especially AC as well as switched DC ref to GMW 8670 could breakdown an insulator and pose a danger to another circuit or a human bein
181. ay need to run the test to quantify any negative effects based upon how dust affects products as described above A code of 6 indicates that the product is very sensitive to dust and dust may not enter the product Water Electronic devices need to be protected from the harmful effects of water Water may produce short circuiting with an immediate negative outcome or it may act as the catalyst when combined with ionic contamination resulting in corrosion or dendritic growth It is anticipated that the water applied in this test would normally come from the following sources GENERAL MOTORS CORPORATION EDSON 2008 110 Condensation or cleaning fluid Dripping water or other fluids may drip down onto the device or may be transported onto the device by following the path of attachment wires The 2 test produces dripping water at the rate of about 1 to 2 drips per second Remember water in the test will be clean and uncontaminated but it may be very contaminated in real world situations Do not dismiss any water reaching the circuit board as it may be a cleaning fluid or other substance in reality Water or liquids that are mistakenly spilt in the vehicle by passengers drinks and cleaning fluids Hi pressure sprayed water coming from a car wash Very high pressure sprayed water coming from the steam cleaning of the engine compartment Code 2 The 2 test should be used for everything in the vehicle All devices in the pa
182. by the customer with a 45 minute dwell Acceleration Factor Defined An acceleration factor is defined by the following equation Life Duration Acceleration Factor ILLU Life Duration Accelerated This equation is transformed as follows Life Duration Life Duration ji Rec cieraiion gt Example for an Interior Module We have used the following assumptions or calculated parameters Tmax field 85 Field Delta T 43 test thermal shock 95 Notice that we are testing to a higher temperature during thermal shock to accelerate the test __ 0 Trin test thermal shock 40 GENERAL MOTORS CORPORATION EDSON 2008 Tmax test ptc 85 Notice that we testing to the standard Tmax value during PTC and not the higher temperature as used in thermal shock because we will have the part functioning and it will be continuously monitored Tmin test ptc 40 Thermal ramp rate thermal shock 15 C min Thermal ramp rate 7 C min Thermal shock inertia lag in minutes 5 Power Temperature Cycling inertia lag in minutes 5 m 2 5 Notice that the m value for lead free is higher than the 2 5 value used for leaded solder Weibull Slope Beta 2 A conservative value is being used because there could be many different locations where failure could occur Sample size is 18 gt Thermal Shock Step 1 Leaded Solder Partitioning One Field Service Life Damag
183. cable to this test FREE FALL The Free Fall Drop Test simulates the device being dropped onto the concrete floor in the assembly plant It is important to know if the product can be damaged internally from such a fall while Showing no signs of the damage externally Some suppliers will say that their product cannot pass this test and that it should not be performed General Motors needs to know the risk if the dropping of GENERAL MOTORS CORPORATION EDSON 2008 the product was to occur the excerpt from 15016750 3 defining assembly plant The following is an how the free fall test is to be run LANDS ON LANDS ON BACK FEET Figure 38 Extract From ISO 16750 3 Showing How To Run The Free Fall Drop Test Parts that will obviously be damaged by the fall shall not be checked e g headlights Parts that could withstand a fall without visible damage shall be checked as follows Perform the test according to IEC 60068 2 32 using the test parameters given in Table 21 Visually examine the devices under test after the falls Table 21 Free fall Parameters For the first fall of each DUT a different dimensional axis shall be chosen The second fall shall be performed on the given DUT with the same dimensional axis but on the opposite side of the housing To be decided 4 3 3 Requirement Hidden damage is not permitted Minor damage of the housing is permitted as long as this does not affect the performanc
184. cations from the Materials Department as specifications evolved Now we only require that the Material Specifications be met based on where the device is located however this also includes colorfastness testing as defined by the Materials Department No additional testing is required over and above the requirements from the Material Specifications You must work with your Materials Engineer to ensure that proper testing is planned and has been executed satisfactorily The 107 GENERAL MOTORS CORPORATION EDSON 2008 following information comes from Alexandra Brigitte Scholz of the GME materials organization Plastic Parts and Components located in the interior of the vehicle shall comply with material part performance per GMW14444 and GMW14651 Plastic Parts and Components located in the exterior of the vehicle shall comply with material part performance per GMW14650 Plastic Parts and Components located in the engine compartment of the vehicle shall comply with the following material part performance requirements All materials shall be resistant to the media they contact such as aliphatic and aromatic hydrocarbons fuels lubricants oils greases and alcohols at their places of use per GMW14650 Resistance to Temperature Temperature Cycle temperature tolerance 3 C ramp between temperatures maximum 1 h Continuous temperature at installation position in the engine compartment lt 110 C 130 C 150 C gt
185. ccumulation of creep damage in 7 Lead Free Creep is significant when T 4 solder as a function leaded and lead free of dwell time UON DG Temperature en 273 Dwell Time Hot and Cold Dwell Times 3 4 Minutes for Leaded Solder and 10 minutes for Lead Free Solder max Product Chamber 250 Thermal Part Temperature 33 GENERAL MOTORS CORPORATION EDSON 2008 ELECTRICAL CONNECTIONS AND CONTACTS FRETTING CORROSION Fretting corrosion is the development of a non conducting sludge on the Surface of contacts when micro motion between the contacts is combined with corrosion of the abraded material This condition will initially create intermittent contact until the build up of the sludge is so great that a sludge resistor is formed Current passing through this sludge resistor generates heat which eventually creates many other problems This problem can be prevented by ensuring that no relative motion occurs between the connection points If that is not totally possible then adequate contact pressure along with an anti fretting corrosion lubricant is suggested Micromotion is in the range of 10 to 200 micrometers and is either caused by vibration or differential thermal expansion and contraction effects Fretting corrosion is most prominent between tin to tin connections but will also occur between tin and gold tin and silver and tin and pa
186. ces to reverse polarity voltage on the power inputs of the device Locations of Applicability Applicable to all devices in the vehicle that have connection to the 12 volt wiring system Procedure Monitoring After the test during final evaluation Operating Type The test shall be performed under both operating types 2 1 loads off and again under 2 2 loads on Use the test method according 15016750 2 Reverse Voltage with the following exemption Table 13 Reverse Polarity Reguirement Test Voltage Test Time V min Criteria Functional status should be at a minimum class C Note This test is not applicable to generators or devices that have an exemption stated in the CTS The Over Voltage Test addresses the two possible conditions when excess voltage will be applied to the vehicle These conditions are During a fast charging process with a high voltage battery charger When the generator regulator fails resulting in an increase in output voltage from the generator The electronic devices the vehicle should be immune to these possible events Purpose The over voltage test addresses two conditions The condition where the generator regulator fails so that the output voltage of the generator rises above normal value The second condition is in case of use of battery chargers with high voltage pulses Locations of Applicability Applicable to all devices in the vehic
187. cesccescescesccesscesces 202 TABLE 20 BASELINE VIBRATION TEST DURATIONS FOR 23 225 TABLE 21 DURATION FOR VIBRATION TESTS WITH REDUCED SAMPLE SIZE 6 AS SHOWN IN THE UNIVERSAL DURABILITY TEST FLOW 226 TABLE 22 ENGINE TRANSMISSION SINUSOIDAL VIBRATION 228 TABLE 23 RANDOM VIBRATION PROFILE ENGINE 02 0000 0 0 228 TABLE 24 RANDOM VIBRATION PROFILE FOR SPRUNG 55 4 00 0 0 230 TABLE 25 RANDOM VIBRATION PROFILE UNSPRUNG 55 0 000 0 1 60 231 TABLE 26 HOURS OF FIELD BASED RANDOM VIBRATION FOR BRACKETS eee 235 TABLE 27 NUMBER OF THERMAL CYCLES WITH A SAMPLE SIZE OF 23 247 TABLE 28 NUMBER OF THERMAL CYCLES WITH A SAMPLE SIZE OF 18 247 TABLE 29 POWER TEMPERATURE CYCLING 444400000000 232 TABLE 30 CYCLING HUMIDITY TEST 8 04 00 253 TABLE 31 CONSTANT HUMIDITY TEST 00000000 422 TABLE 32 SUMMARY OF SALT CORROSION TESTING 261 TABLE 33 SEAL EVALUATION REQUIREMENTS 265 TABLE 34 SHIPPIN
188. considered the worst case Testing with shorter dwell periods will accumulate only a portion of the damage that would have been created by the customer with a 45 minute dwell gt Acceleration Factor Defined An acceleration factor is defined by the following equation Acceleration Factor _ Life Duration Life Duration Accelerated This equation is transformed as follows Life Duration Life Duration ji gt Example for Interior Module We have used the following assumptions or calculated parameters Tmax field 85 Field Delta T 43 Tmax test thermal shock 95 Notice that we are testing to a higher temperature during thermal shock to accelerate the test __ Trin test thermal shock 40 283 GENERAL MOTORS CORPORATION EDSON 2008 Tmax test ptc 85 Notice that we testing to the standard Tmax value during PTC and not the higher temperature as used in thermal shock because we will have the part functioning and it will be continuously monitored Tmin test ptc 40 Thermal ramp rate thermal shock 15 C min Thermal ramp rate 7 C min Thermal shock inertia lag in minutes 5 Power Temperature Cycling inertia lag in minutes 5 m 2 65 Notice that the m value for lead free is higher than the 2 5 value used for leaded solder Weibull Slope Beta 2 A conservative value is being used because there could be many different locatio
189. ction dissection results should be used during DRBTR The E E device Internal amp External Inspection is a visual microscopic review of the device s case internal parts at the completion of reliability testing as specified in the Validation Test Flow section The purpose of this inspection is to identify any structural faults material component degradation or residues and near to failure conditions caused by the reliability testing inspection shall use visual aids i e magnifiers microscopes dyes etc as necessary The following are examples of items the inspection shall examine for 1 DUT Mechanical and Structural Integrity Signs of degradation cracks melting wear fastener failures etc 2 Solder Component Lead Fatigue Cracks or Creep Pad lift Emphasis on large integrated circuits large massive components or connector 3 Damaged terminations especially at the end or corner lead pins Also components in high flexure areas of the circuit board Surface Mount Components Emphasis on surface mount components near circuit board edges supports or carrier tabs Also surface mount components located high flexure areas of the circuit board and near connector terminations 4 Large Component Integrity and Attachment Leaky electrolytic Capacitors contaminated relays heat sink rail attachments etc 5 Material Degradation Growth or Residues of Corrosion Melted
190. d Note m 2 5 for leaded solder Solder represents worst case in terms of the m values and that will be the target material used in this document field m 2 5 Coffin Manson Acceleration Factor E 14 408 gt PTC Step 10 Leaded Solder Applying The Acceleration Factor For Dwell Time Effect To The PTC Cycles We are using an optimum damage per unit of time dwell period during testing of 4 minutes both hot and cold While this is optimum on a per unit of time basis it does not encompass all of the damage that would have been generated by the severe customer using a longer 45 minute dwell period The following acceleration factor accounts for the lost damage with a shorter dwell period Dwell Effect Acceleration Factor 768x min Dwell Effect Acceleration Factor 768x 4 842 gt PTC Step 11 Leaded Solder Acceleration Factor Resulting From The Thermal Ramp Rate The thermal ramp rate used in making the temperature transitions has an effect on leaded solder This factor is derived from the modeling work of J P Clech 295 GENERAL MOTORS CORPORATION EDSON 2008 is shown figures 14a of reference 14 faster ramp rate will result in an acceleration factor greater than one Ramp Rate Acceleration Factor 80094 x Ramp Rate 0964 Ramp Rate Acceleration Factor 80094 x Ramp Rate 0964 966 gt Step 12 Leaded Solder Acceleration Factor For The Maximum Temper
191. d is shown below 4WD Full Size Truck PU or Utility 600 hours of vibration 2WD Full Size Truck PU or Utility 600 hours of vibration 4WD Mid Size PU amp Rec Off Road 150 hours of vibration 2WD Mid Size PU amp Rec Off Road 150 hours of vibration 2WD Mid Size Utility 150 hours of vibration Mid Size SUV and Van 125 hours of vibration Passenger Vehicle 84 hours of vibration No engineer wants to run a vibration test for these many hours in each of the three axes so the test is accelerated by increasing the Grms value while 4WD Mid Size Utility 150 hours of vibration GENERAL MOTORS CORPORATION EDSON 2008 316 decreasing the test duration The equations Appendix G are used for this purpose Whatever level of vibration is used the basic profile in GMW3172 Should be used however the profile must be rescaled to fit the Grms level desired We must begin with an understanding that the bracket will go into resonance if the resonant frequency of the bracket occurs within the range of frequencies provided by the input PSD A bracket will experience the greatest degree of fatigue damage when exposed to its resonant frequency Resonance is powered by the level of energy Pin provided at the resonant frequency This value is read from the Y axis at the resonant frequency F from the PSD graph This energy level is amplified by the phenomenon of resonance with a degree of magnification provid
192. d as perpendicular to the plane of the circuit board and not relative to vehicle orientation However in situation where large mass items are attached to the circuit board or the circuit board employs a daughter board attached at a 90 degree angle then the vibration testing should be distributed across all axes that will stress the attachments The statistical process used in the above is as follows 1 In R Desired Sample Size Test Duration Standard Test Duration x Multiple Life Factor Standard Sample Size GENERAL MOTORS CORPORATION EDSON 2008 224 225 Vibration Sine Random Mounting Location Engine Transmission Purpose The vibration of a piston engine can be split up into the sinusoidal vibration which results from the unbalanced mass forces in the cylinders and the random noise due to all other vibration sources of an engine The influence of bad road driving is comprehended in the frequency range from 10 Hz to 100 Hz The main failure by this test is breakage due to fatigue The severity and the duration of the vibration test is the same for cars and trucks Locations of Applicability This test is applicable to devices attached to the engine or the transmission of a car or a truck Figure 30 Sources of Engine Vibration Pistons The Primary Source Of Sinusoidal Vibration Valves The Primary Source Of Random Vibration Procedure Monitoring Constant mo
193. d critical products may require screening during the startup of production to ensure that early quality spills are detected and prevented before reaching the vehicle assembly line Screening is expensive and time consuming and should only be used when absolutely necessary While screening may be frequent during product startup it can be decreased in frequency as production processes brought under stable control Screening methodology iS described in GMW8287 Precision CUBE amp inc AND I EXPECT A COMPLETE REVI SION OF OUR Q C PROCEDURES WE RE CUTTING TOO MANY CORNERS EVALUATION OF ENGINEERING CHANGES AFTER PRODUCTION An abbreviated test plan is to be formulated to address post validation engineering changes using the ADV Task Checklist as a starting point It is suggested that the following principles by applied in determining which tests are necessary e If a surface mounted component is being made smaller then there is little need for thermal fatigue testing If a larger surface mounted device is being used then there may be a need for thermal fatigue testing Physical dimensions are important when it comes to thermal fatigue because expansion and contraction GENERAL MOTORS CORPORATION EDSON 2008 stresses directly related to the size of the component e If a heavy component is being added to the circuit board or if an existing component will significantly increase in wei
194. d free solder Lead free vehicle components shall be identified with readable markings showing the stricken through chemical symbol for lead GENERAL MOTORS CORPORATION EDSON 2008 74 75 The current understanding of solder reliability is based on 75 years of using leaded solder alloys The entire world is nervous concerning the use of a new material that plays such an important role in determining product reliability or un reliability of electronics What Type Of Lead Free Solder Lead free solder is available in two basic flavors SAC based solder Tin Silver Copper and everything else SAC solder is the preferred material as it has been highly studied and has proven to be the most reliable Bismuth based solders have the advantage of a lower melting point but pose many other reliability problems General Motors Ford Motor Company and many of our suppliers have chosen to ban the use of bismuth based solder because of the many reliability risks associated with this material Of special note is the problem of lead contamination with bismuth based solder If a single component that has been tinned with a tin lead alloy is used in a bismuth based soldering operation there is a strong potential that there will be enough lead to form a localized contamination point where the lead combines with the tin and the bismuth This three way alloy will result in a localized mixture with the low melting point of 96 C This
195. d only once Where is the board flexure the greatest Board flexure is greatest in the center of the unsupported area of the circuit board when the board is Supported at the four corners The resulting arc of curvature in the circuit board is greatest in the direction parallel to the shorter side of a rectangular circuit board Devices mounted in the center of the circuit board are more at risk and those mounted parallel to the shorter side of the circuit board are most at risk The following graphic should help you understand this concept GENERAL MOTORS CORPORATION EDSON 2008 30 31 What is the relationship between the input displacement frequency and the G level The relationship between the single amplitude displacement of the circuit board inches the frequency Hz and the energy level Gs for the input vibration is as follows f xY _ Gx9 8 be rewritten as 9 8 f From this equation we can see that if we required a fixed displacement across the full range of frequencies that the G level would go up exponentially with increasing frequency The above equation portrays the input vibration The product being vibrated will respond to the input vibration as a function of the products resonant frequency The input vibration level will become amplified to a maximum level at the product resonant frequency The amplification factor is expressed as the Q transmissibility at re
196. d under operating type 2 1 DUT will function under operating type 3 2 when energized during the final evaluation at end of the test Conduct HAST per EIA JEDEC Standard JESD22 A110 B Use the equivalencies described in Appendix Criteria The DUT shall not exhibit unacceptable levels of current rise during the test and should function properly following cool down FSC Figure 21 HAST Chamber With Door Open EDSON 2008 192 193 Figure 22 HAST Chamber View Of The Racks That Hold The Parts Figure 23 HAST Chamber View of Internal Electrical Junction Block DEVELOPMENT RESULTS REVIEW A development results review should be performed on the results of the development tasks with the intent of identifying where there is a lack of design margin A refocusing of attention during validation may be necessary as a result of this Development Results Review Purpose Identify weaknesses or lack of design margin and initiate corrective action now A refocusing of attention during validation may result based upon the outcome of the analytical tasks Procedure Perform the review Appendix B design per Criteria Initiate corrective action as early as possible in the product development cycle End of Development Activities GENERAL MOTORS CORPORATION EDSON 2008 DESIGN VALIDATION ACTIVITIES ELECTRICAL TRANSIENT TESTS PARASITIC CURRENT The Paras
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198. degradation such as unacceptable current draw voltage drop changes GENERAL MOTORS CORPORATION EDSON 2008 ISOLATION RESISTANCE The Isolation Evaluation Test should only be performed when there is concern that the insulation quality between critical terminals may be inadequate especially if the insulation material is moisture absorbing and the saturated insulator has a drastically reduced insulating ability This becomes critical when conductors that are in close proximity carrying significantly different levels of voltage A voltage differential of 30 or more volts represents a good decision criteria for when this test should be required Inductive voltage step up devices may produce a situation where this test should be run This test may also be required for certain sensors where change in current is critical to the function of the device The Isolation Evaluation Test should be run following the 10 day constant humidity test Following the 10 day constant humidity test the DUT should be allowed to dry to the touch prior to running the isolation test The isolation test shall always be run within three hours of completing the humidity test unless special accommodations are made If the isolation test cannot be run within three hours of completing the humidity test then special accommodations shall be made to ensure that all of the moisture does not escape from the circuit board The DUT shall b
199. disrupt functionality The valid range of all analog inputs shall be scaled so that hard ground shorts voltage shorts and open circuits are outside a valid operation range so that fault conditions can be recognized by the processor and appropriate diagnostic codes set Verify that appropriate diagnostic codes are correctly set 3 It is not acceptable for a fault injection to create a system or software runaway condition or a lock up condition such as a continuous loop waiting for an action to occur Verify that I O time out conditions and any related diagnostics are functioning properly 4 It is not acceptable for a fault injected on one circuit or function to cause a disruption in a any other circuit or function GENERAL MOTORS CORPORATION EDSON 2008 Appendix Designing A Bracket With Adequate Fatigue Life The vibration test requirements defined in this document are based on the ISO 16750 3 specification This specification provides the worst case vibration for any location in the vehicle within the specified grouping sprung mass un sprung mass engine Testing to this specification ensures that the product will be robust if used in different locations on different vehicles or if relocated in a re use application The test levels are significantly different between the different groupings sprung mass un sprung mass engine and product would need to be re validated if relocated from a body mounted location to an engine
200. dity Test Profile Cyclic Humidity Test Temperature Profile Perform The Following Profile Five Times 10 Days 5 Pay Attention To Anomalies Resulting From Condensation Of Moisture Temperature Change Is To Occur Within 1 5 Hours Temperature Degrees C 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Hours Over Two Days Criteria Functional Status shall be class A significant changes in quiescent current or product performance should occur during any time during the test or at the end of the test GENERAL MOTORS CORPORATION EDSON 2008 HUMID HEAT CONSTANT HHCO The Humid Heat Constant Test provides increased vapor pressure with high humidity and an increase in temperature over normal operation Water vapor molecules are smaller in diameter than water molecules and will permeate plastic encapsulations seals capacitors The ingress of water vapor may lead to malfunction of components or create a change in parametric values Intermittent Operation may occur during this test and constant monitoring is required to detect dendrite shorting or malfunction from the ingress of moisture into the circuit board or the components on the circuit board Unique products such as a camera may monitored periodically rather than continuously because of condensation generated image blur The humidity level of 85 95 is real
201. dure Choose ihe for tha first the fall wilh ihe same axis but in the opposite direction step 1 and 2 wilh tha next sampi in step 1 and 2 with ihe third sample in Z Axis Remark Continuous Document all visual damages by picture and add tham to the test repart Monitoring should Perform a Tuncitional test refer to 5 25 when needed Manilcring Method and Definition of Whal Being Moenibared The product wil nof monitored during the drop portion of this test The product will ba energized and evaluated Tollkwing ihe lest and wil Ge subsequently dissected and visualy amined in detail for possible buds of probleme Pass Fal Criteria The DUT must pass the functional best or the damage is judged by GM Validation Engineer Tasal Fasule The supplier shall provide a summary af the best results how many passed how many faled andthe detaib af al failures GENERAL MOTORS CORPORATION EDSON 2008 272 273 Appendix Reliability Design Reviews Changed Product Assessment Using Design Review Based on Failure Mode DRBFM Design Review 1 amp 2 o What aspect of this design is different or represents change from previous designs What concerns result from this change failure mechanisms What impact will the different from previous have on the final customer or on other inter related components in the system What measures will
202. during this test Back in the days of GM9123P prior to 1999 there was no thermal shock but 1036 PTC were required and that took months of testing Testing now takes about 1 3 the time that it did before the turn of the century Purpose The purpose of this test is to determine if the DUT is able to meet specification requirements when subjected to the power temperature cycling stresses that cause failures related to mechanical attachments integrated circuit dies electromigration and solder creep Locations of Applicability This test is applicable to all areas of the vehicle This test is essential following thermal shock Procedure Monitoring Constant monitoring is required during this entire test to detect intermittent failures Operating Type The test shall be performed under operating type 3 2 Perform as described in figure 44 and table 29 GENERAL MOTORS CORPORATION EDSON 2008 248 Criteria Functional status shall be class A The Power Temperature Cycle Test Shall be performed according IEC 60068 2 14 Nb The electrical input output duty cycle Shall be scheduled such that the required minimum number of 1 life cycles is evenly distributed during the total test The control instrumentation must be capable of synchronizing the DUT on off time with the chamber temperature transitions Figure 44 Power Temperature Cycle Lead Free Dwell Times Shown 100 10 Mi
203. e Bullets 200 000 Tons lead shot in shotgun shells eliminated Electronics 18 500 Tons less than 5 of total Wheel weights 100 000 Tons being eliminated Elimination of lead from paint and gasoline has had the greatest effect Average US Lead Levels in Micrograms per Deciliter of Blood 0 1940 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 The Above Graphic From Dr Ronald Lasky Timothy Jensen Indium Corp c 48 Flex BGA 144 Aes T Pb free O Pb free SnPb 8 SnPb Pb free SnPb 3000 2000 1000 o i E S 5 e rn s 46 96 0 Above Graphic From CALCE Shows The Similarity Of Performance Between Lead Free And Leaded Solder 43 GENERAL MOTORS CORPORATION EDSON 2008 Solidus and Liquidus Values For Lead Free Solder Increased Processing Temperature May Result In Damaged Components Estimation of Ternary Liquidus Surface 10 23 95 Based on Marquette saturation data with NIFU and NIST thermal anaivsis X Cu Reflow Soldering Temp 260 C seconds Terp 231 10 seconds 5 10 seconds 5 7 96 5513 99 3510 7 95 5S5n3 8 g0 93 6S5n4 Agl 7Cu 96 2512 5 0 8 10 550 91 78n3 SAg4 8Bi 90 58n7 S5Bi2Ag 58B142 Sn 955158
204. e When the product is mounted on rubber isolators or grommets the above test may generate excessive heat within the rubber causing abnormal failure of the rubber isolators The following process is suggested to prevent this problem e Apply the standard specification level vibration to the rubber mounted device for only a few minutes and measure the Grms value Grms PSD PSD on the device downstream from the rubber isolator e Test as explained in section 15 using the new Grms value Grms and the new PSD PSD as the requirement with the rubber isolators removed from the system This will prevent the accelerated vibration level used in the specification from creating heat based damage in the rubber isolators Figure 49 Weibull Plotting Example Probability Weibull 99 90 The test was First LB suspended E vin before these two failures were allowed LL gt to occur B amp 9 S 10 00 Last Failure 5 00 Requirement gt 1 00 1 00 10 00 100 00 b 2 5000 Hours of Vibration The median rank values shown in this table are the expected percentile plotting points to be used in Weibull Analysis First select the total number of samples that were placed on test at one time If six samples were placed on test and then t
205. e allowed to dry to the touch and then sealed in zip lock type plastic bag The isolation test can then be within 24 hours after the humidity test If the isolation test needs to be re run in PV then the 10 day constant humidity pre treatment test can be replaced with 3 days of the same constant humidity test Purpose The loss of insulation quality between traces could lead to malfunction and other performance problems This is often due to reduced spacing of traces or to the degradation of dielectric material from humidity ingress The test may also be used to evaluate thin film insulator degradation from moisture especially for inductive loads Additionally it may be used to evaluate degradation of an isolation material which is used internal to a device that is critical to performance e g sensors where change in current has to be precise A detailed planning must test to analysis be during performed GENERAL MOTORS CORPORATION EDSON 2008 212 213 determine which inputs outputs should be tested and at what voltage levels The default voltage of 500 V as stated in the test procedure can be adjusted to a level specific for the component E g in case of inductive components like a motor a test voltage of gt 300 V would be suitable whereas for a PCB with an inductive load which creates voltages gt 30 V the test voltages must be suited to the tested circuits The module m
206. e and what does sprung and un sprung mass mean e A sprung mass is anything attached to the body or the chassis An un sprung mass is anything attached to the wheels tires or suspension system below the springs of the vehicle Determine where your product will be attached and use the corresponding random vibration test My supplier is telling me that the vibration test GMW3172 is too severe for the location where his product will be located What should I do e The vibration profiles defined in GMW3172 are the result of engineers from many different car companies and component suppliers pooling their data to derive a worst case profile for each of the major location categories This effort resulted in the formation of the ISO16750 3 international specification for vibration testing For example the sprung mass profile defined in this document is the worst case for anywhere on the body or frame of the vehicle Designing a component to meet this requirement means that it could be reused in another location on a different vehicle without the need to re validate the product The underlying strategy is to have a requirement to design to before a vehicle would ever be available When an actual vehicle becomes available it will be too late to economically change the product if improvement is needed When a product will never change its location significantly and when that product is located in a least severe area of the location category
207. e Into The Thermal Shock Damage Target and The PTC Damage Target We wish to generate 75 of the total damage using thermal shock in the interest of faster and less expensive testing 7300X 75 5475 Thermal Cycles gt Thermal Shock Step 2 Leaded Solder Applying The Coffin Manson Equation To The 75 Damage To Reduce The Number Of Thermal Cycles With Increased Thermal Range Testing We wish to generate an equivalent degree of damage using fewer cycles but will offset the fewer cycles with greater strain using expanded thermal range testing The specification is 409 to 85 C delta T of 125 C however in thermal shock we are generating thermal fatigue damage with the device un powered and can use an expanded temperature range We can extend the low temperature down to the Homologous Temperature point and we can increase the high temperature provided we do not exceed material limits The product in this example can withstand 40 C to 95 C Delta T is 135 C and we will use this beyond specification thermal test range to decrease the number of thermal cycles required on test The Coffin Manson Equation gives us the equivalent damage relationship GENERAL MOTORS CORPORATION EDSON 2008 292 Coffin Manson Acceleration Factor E field Note m 2 5 for leaded solder Solder represents worst case in terms of the m values and that will the target material used in this document m 2 5 AT Coffin Man
208. e depends the operating mode Unom Volts Generator Status Operating Not Operating CODE LETTER FOR MECHANICAL LOADS The Mechanical Loads Code Letter requires you to define the type of vehicle in which this component will be used now or in the future because vibration testing duration is different between cars and trucks What s a Truck A truck is defined as a pickup or commercial vehicle What s a Car A passenger car SUV or crossover vehicle Code letters or and through J should be used for pickup trucks and commercial vehicles and or and through F should be used on everything else Remember A sprung mass rs anything attached 1o body or chassis Table 3 Code Letter for Mechanical Loads Requirements Crush Test Random Mechanical M Vibration Shock 1 Method without special Yes No Yes balancing feature Engine Envelope 2 Method A without special Yes No Yes balancing feature Car Duration Sprung vee mass 101 GENERAL MOTORS CORPORATION EDSON 2008 EE Requirements Crush Test Random Mechanical Vibration Shock Letter Method A amp B Car Duration Sprung mass Method Car Duration Sprung mass Unsprung mass Method A Truck Duration Sprung mass NE Method A amp B Truck Duration Sprung mass Method A Truck Duration Sprung mass EN Method A Truck
209. e formation of dew liquid water on the circuit board Test Leg 6 PERFORMANCE ROBUSTNESS EVALUATIONS This test leg is composed of the many robustness evaluation tests for non cumulative damage type events Each test should be run on GENERAL MOTORS CORPORATION EDSON 2008 at least three parts but all of the tests do not need to be run on the same three parts The supplier has discretion as to how these tests will be allocated over the available product samples Test Leg 7 KEY LIFE TEST FOR Bused Electrical Centers 5 should also be subjected to the other test legs Fretting corrosion is a primary problem for BEC s and this test will reveal loss of good connection resulting from the combination of vibration induced fretting and corrosion BUSSED ELECTRICAL CENTERS This test leg is only to be run on UNIVERSAL ELECTRONIC DEVICE DURABILITY TEST FLOW The following figures provide a test flows that are to be used to validate products using the specific tests described in this document The test legs Should be run in parallel to minimize total test time Synergistic failure mechanisms have been accounted for by series testing as shown Deviations from this test flow require GM Validation Engineering approval Surrogate test data especially when using lead free solder will not be accepted A leaded and a lead free version of the test flow is shown Please note that all of the parts should be evalua
210. e in determining what tests should be run for Product Validation PV In addition to the tests defined in the flow chart Audit Screening Activity is an optional activity that may be necessary for products that represent significant risk at the start of production It is essential that thought be given to the basic failure mechanisms described in the beginning of this document when attempting to decide what PV tests should be run The basic thought process is as follows A new small component added Humidity and Performance A large component added Thermal Fatigue and Vibration and Performance Changes in trace layout Frost Humidity and Performance Changes in how the circuit board is supported Vibration and Performance Changes in the housing Seal Evaluation when applicable and Environmental Protection Code testing GENERAL MOTORS CORPORATION EDSON 2008 samples used during PV testing should contain solder repairs typical in type and quantity that would exist during production Begin with the assumption that 20 of the PV samples should include solder repairs This number should be modified by past experience of the supplier on similar products being manufactured Procedure This Program Product Validation Product Validation Other tests be added if the design changes between DV and PV due to corrective action or supplier driven design changes If hardware produced from production tools equ
211. e of the DUT Proper performance shall be proven following the test Functional status shall be Class C as defined in ISO 16750 1 2003 Purpose To determine the level of damage the DUT is subjected to the mechanical A system component may drop down stresses to the floor during handling assembly GENERAL MOTORS CORPORATION EDSON 2008 236 2947 Locations of Applicability This test is applicable to all devices that may be dropped during vehicle assembly or service Procedure Monitoring The DUT is only evaluated at the end of the test Operating Type test shall be performed under operating type 1 1 Use free fall test methods according to ISO 16750 3 Criteria e The FSC code is not applicable to this test e If there is no visible external damage to the DUT then the DUT shall have no internal damage and shall pass the Functional Parametric Test at the end of test e If there is visible external damage to the DUT and the damage is judged by GM Validation Engineer to be e Insignificant then the DUT shall have no internal damage and shall pass the Functional and Parametric Test at the end of test e Significant then the DUT does not have to meet the performance requirements TEMPERATURE TESTS LOW TEMPERATURE WAKEUP The Low Temperature Wakeup Test evaluates the ability of the product to wakeup at low temperature with full functionality This was once just a low te
212. e purpose and scope of the FSC is to provide a general method for defining the functional performance for the functions of automotive E E devices upon exposure to test conditions or real world operation conditions An unwanted operation of the DUT is not allowed in any of the following classes The device must not create a hazard when operated with voltages outside of the design intent This is applicable to all classes of FSC described above Definition of FSC Class All functions of the device system perform as designed during and after the test All functions of the device system perform as designed during the test However one or more of them may go beyond the specified tolerance All functions return automatically to within normal limits after the test Memory functions shall remain class A One or more functions of a device system do not perform as designed during the test but return automatically to normal operation after the test One or more functions of a device system do not perform as designed during the test and do not return to normal operation after the test until the device system is reset by simple operator use action One or more functions of a device system do not perform as designed during and after the test and cannot be returned to proper operation without repairing or replacing the device system 95 GENERAL MOTORS CORPORATION EDSON 2008 CODE DESIGNATION BY LOCATION IN THE VEHICLE The followi
213. e time as the HALT test The supplier must not walk in at the last minute to run this test or assume that it will be tested at the whole vehicle level Ground Path Inductance Sensitivity M C This test is only needed if there is flash memory that will be programmed with the wiring harness in place Devices that may be programmed in the plant should receive this test Device State Change Waveform Characterization This test is needed to characterize the degree of transients produced during the state change of the device GENERAL MOTORS CORPORATION EDSON 2008 146 This Program Supervisor Performance Evaluation This evaluation is used to ensure proper function of the supervisor function in the circuit design All microprocessor based devices should receive this evaluation Fault Injection 88 Fault Injection Testing focuses systems where media or interactions with the customer may produce abusive effects A good example of where this would apply is on radios with CD operations Mechanical Tests Highly Accelerated Life Test HALT 9 HALT is a qualitative test that provides a one day test duration insight into the temperature design margins and the vibration design margins for the product This test should be used for most circuit board devices but would not be required for very simple circuit boards or for large structural devices This test represents the industry
214. ed Electrical Center devices Procedure Monitoring Monitor only for overheating while waiting for the fuse to open Operating Type The test shall be performed under operating type 3 2 All circuits are to be protected using the approved application circuit protection device as detailed on the part drawing or specification fuse circuit breaker etc 1 Raise and stabilize the chamber temperature to Tmax 2 Apply Unom to the DUT The load circuit shall in operation Apply short circuit condition to the output so that the load current is 1 35 times the nominal fuse rate current Irp of protection 4 Record the fuse blow times and verify that they are within the fuse specification 5 Repeat with shunts in place of fuses and hold current to upper fuse specification blow time limit 6 Repeat steps 3 to 5 with a short circuit condition so that the load current is 2 times the Irp and again with 3 5 times the Irp The test duration shall be derived from the corresponding fuse protection characteristic curve ISO 8820 Operating Time Rating considering the upper tolerance plus 10 Criteria Functional Status shall be class C The external short circuit fault shall not prevent any other interface from meeting requirements It is also required that the tested outputs be included in parametric measurements These measurements shall be capable of detecting potential output
215. ed Electrical Centers statistically addressed with requirements for demonstrating a 97 level of reliability Many qualitative tests are used as pre treatments or post treatments for other tests in the test flow The sequencing of these tests is based on known interactions between the different stress types Many of these interactions have become so Significant over the years that they now merit their own failure mechanism name Examples of these interactions can be seen in the following graphic and are typified by Fretting Corrosion and Stress Corrosion Cracking THE TWO BASIC GROUPINGS OF FAILURE MECHANISMS Simple Summary Of Failure Mechanisms Overstress A Single Stress Cumulative Damage When Continued Excursion Exceeds the Strength Use Exceeds the Endurance Limit Performance Inadequacies Not Wear Pay Related to Material Damage p Fretting Corrosion Corrosion Electrical c Example 12 volt power Stress Corrosion Cracking supply that can only Thermal supply 10 volts Fatig ue Cosmetic Material Overstress Failure Mechanism Ti ecnanisms Cree e Fracture Temperature Buckling Aging Yielding and Brinnelling Electrical Overstress nterdiffusion Electrostatic Discharge Diffusion Depolymerization Based Dielectric Breakdown Events Thermal Breakdown Embrittlement Spalling Dendrite Shorts Metal Migration Opens From Loss Of Material GENERAL MOT
216. ed by the calculated value of Q Let s begin our bracket designing example by assuming that we will use the sprung mass vibration specification defined in GMW3172 for a car or SUV This specification says that the bracket with the product attached needs to survive a one life requirement of 2 84 Grms applied for 8 hours in each of the three major axes The total one life test duration would be 8 8 8 24 hours We begin by defining the following The weight of the bracket and the device it will carry W assembly The location of the Center of Gravity of the bracket and device as it will be assembled in the vehicle CG The resonant frequency of the bracket and device assembly performed by Finite Element Analysis Fn The level of G Hz Pin that occurs at the resonant frequency F4 This value is read off of the Y axis of the Power Spectral Density graph PSD at the resonant frequency F The approximate level of dampening Q given the assumption that this is a lightly damped system Q 2x JF The acceleration level operating on the weight of the bracket plus device is equal to G E X Q out in 217 GENERAL MOTORS CORPORATION EDSON 2008 These values for our example are as follows W assembly 2 pounds The Center of Gravity is marked with a red X on the part this will be used latter to determine the moment being applied to the bracket and aid in the calculation of internal st
217. ed on the materials of concern Radiat N re The two photographs above illustrate the results of a failure analysis task carried out on a glob top encapsulated chip on board COB device In the original design the CTE thermal co efficient of expansion of the encapsulant material had not been well matched to the CTEs of the other materials in the assembly During changes of temperature experienced during field operating Author Mechanism Al wirebonds Au Al fracture in wirebonds PQFP delamination bond failure ASTM 2024 Aluminum alloy AD eee Norris la ndzbe ky Hall i Scharr Dunn Peddada Blish N h QN aalo a ce 9 015 5 0 5 3 a 7 8 9 3 0 199 oA 131 0 0 2 0 0 sd 150 N sp conditions the encapsulant expanded excessively with respect to the other materials and stressed Pere D cracking 4 8 6 2 the bond wires This led to thinning and breakage Dunn Janay rs 1 of the bond wires at the illustrated points Figure 2 Chip Board Construction COMPLIANT PIN CONSTRUCTION A compliant pin type construction forms an electrical connection from one circuit board to another circuit board or from a connector to a circuit board by using a pin inserted into a VIA barrel which is located
218. ed only for reference but were used as the foundation for the values shown in tables 27 and 28 GENERAL MOTORS CORPORATION EDSON 2008 244 Table 27 Number Of Thermal Cycles With A Sample Size Of 23 Parts Code Letter Location In The Vehicle Combined Sample Size Sample Size For Number Of 23 23 Temperature Thermal Cycles WithA Sample Size Of 23 Parts Number Of PTC Cycles Number Of Thermal Combined Thermal Shock PTC A B C and Inside the passenger D compartment luggage compartment or attached to the exterior of the vehicle but not under the hood or above the exhaust system vehicle engine Table 28 Number Of Thermal Cycles With A Sample Size Of 18 Parts Location In The Vehicle Combined Sample Size Sample Size For Number Of 18 18 Temperature Thermal Cycles With A Sample Size Of 18 Parts Code Letter A B C and Inside the passenger D compartment luggage compartment or attached to the exterior of the vehicle but not under the hood or above the exhaust system Combined Thermal Shock PTC 843 Number Of PTC Cycles Number Of Thermal Shock Cycles 632 211 vehicle G H and I Attached to or inside the engine total cycles 2248 __ 87 1 Cyclic Humidity Constant Humidit 1012 759 253 Note Components that are temperature coded as G H and I shall be interrupted after 1236 thermal cycles to perform the Hum
219. eline Vibration Test Durations for 23 Parts Duration hours Location Body Style gt ee ee Engine Body Or Chassis Sprung Mass Truc Un Sprung om test flow provides a recommended sample size and the following table shows how the baseline test durations are to be changed to reflect the use of a smaller sample size Vibration testing with a reduced sample size requires an increase in test duration statistically adjusted test duration needs to be determined according to Appendix A Weibull slope of B 2 5 has been used to reduce the sample size while increasing the test duration Special Note If a device fails during vibration prior to the required number of hours in the Z axis as listed below the success run test plan can be converted to a test to failure test plan The remaining parts that have not failed should remain on test until 3 more failures occur The total of 4 failures should be plotted on Weibull paper to determine if the 225 GENERAL MOTORS CORPORATION EDSON 2008 specification of R 97 at 8 hours has been met Details of Weibull plotting are described in Appendix D Table 21 Duration for Vibration Tests With Reduced Sample Size 6 As Shown In The Universal Durability Test Flow Duration hours Location Body Style a Engine Body Or Chassis Sprung Mass Un Sprung Mass Note For the vibration test only The Z axis is define
220. elopment Analysis refers to activities that can be carried out on the design without the need for a physical product The analysis of the circuit design would be a typical task that can occur prior to making actual parts Development refers to activities that can be carried out on a very small sample of product as soon as physical product is available These are tests that are designed to reveal outlier weaknesses by testing with stress beyond the specification This activity is designed as an early warning opportunity to correct weaknesses at a time when correction is most economical These tests are not intended to demonstrate reliability Validation refers to activities that prove out the final design before assembly into a vehicle These activities fall into two categories Qualitative Tests that have empirically shown their ability to discriminate between good and bad product Quantitative Tests that statistically demonstrate reliability requirements Begin with a review of the Quick Start Flowchart and the Frequently Asked Questions Study The Universal Durability Test Flow as this is a very valuable focal point for understanding and discussing the sequencing of the various tests Identify your code sequence from table 1 and then use the ADV Task Checklist to identify what tests should and should not be run on your product This must be clearly conveyed to the supplier Remember not every test need
221. els test simulates the condition where there are significant degrees of AC ripple on top of the base DC voltage under special circumstances such as when there is no battery in the car or when the generator is not providing adequate dampening of the ripple signal The second superimposed alternating voltage test addresses normal operating conditions and evaluates the DUT s robustness against pulse voltage inputs on the base 12 volt DC lines The following are examples of problems which generated the need for this test Replacement of position light bulbs with switching buck converter driven single high intensity LED Causing current consumption variations at feeding side smart electrical center and setting faulty open circuit fault codes e Electronic Brake Modulator with parallel Vbatt feeds with separate serial diodes with different internal time constant on supply voltage variations leading to power ASIC destruction due to distributed supply pin voltage differences Variable Effort Steering VES with PWM controlled constant current actuator outputs Output EMC LC Pi filter driven at resonance frequency giving current spikes causing unintended short circuit protection shutdown Neither of these tests are intended to evaluate generator noise coming through the radio Sinusoidal Superimposed Voltage Test Beyond Normal Levels Purpose Verify the performance of the E E device when the supply voltage is Superimp
222. ematic and those at the bottom in orange and red being of greatest risk You can see that Tin Copper finishes and Bright Tin finishes represent the greatest risk The numbers shown in the table are the distribution of percentage values of iNEMI companies placing each material into the three different categories For example if we consider Matte Tin Sn with Nickel Underplate we see that 9 of the companies would place this material in category one and 91 of the companies would place this material in category two This material Matte Tin Sn with Nickel Underplate is considered to be of very low risk for tin whisker formation as it resides near the top of the chart in the blue area Card Cage Edge Guides _ Snontaneous Whisker Growth Tin Whiskers we 1 VLA FEL lin Whiskers GENERAL MOTORS CORPORATION EDSON 2008 76 77 Component Lead Free Finishes Whisker Test Requirements Solderable Finish Base Material Cu 7025 194 etc Low Expansion Alloy Ceramic such as Alloy 42 Kovar resistors and capa eor no lead Cat 3 e Cat eae 100 100 Cat 2 3 Matte 5n wi Nickel are 1 underplate Reflowed 5n Hot Dipped 55 5 14 SnAgCu Matte Sn w Silver D 10 Hot Dipped SnAg Hot I p E sn pw 154648 Matte Sa 150C ET SaCu 150 d eal T 1 Matte p Semi Matte
223. encies up to 1000 Hz This will require that 2000 data samples be taken every second in order to quantify energy at 1000 Hz Only five minutes of vibration data needs to be taken while the vehicle is driven on the Belgian Blocks This time domain data must then be converted into the frequency domain using Fast Fourier Transform FFT in Matlab Use a Hanning windowing and linear average G values when performing the calculations Do not use peak hold as that is an artificially elevated value Ultimately a PSD is generated so that the bracket with DUT mass can be tested on an Electro Dynamic Shaker The total test time on the Belgian Blocks is defined in the following table for 100 000 miles Alternatively for example if the VTS defines the life requirement to be 150 000 miles then the test duration must be multiplied by 1 5 The vibration level should then be increased to the point where the test duration is reduced from the hours defined in the table above table 22 to 8 hours The test must be conducted for 8 hours in each axis to account for the multi axial vibration in a vehicle The GENERAL MOTORS CORPORATION EDSON 2008 232 233 calculations of converting 600 hour test at one level of GRMS toa Shorter duration test at increased level of GRMS is explained in Appendix Table 26 Hours of Field Based Random Vibration For Brackets 4WD Full Size Truck 600 hours of PU or Utili
224. er to detach or open According to my calculations I can support you as long as you don t jump up and down TEMPERATURE ANALYSIS HIGH ALTITUDE OPERATION OVERHEATING ANALYSIS Convectively cooled devices that are operated at high altitude and at room temperature or above may be at risk of overheating as a result of reduced air density at higher elevations Air is less dense at high altitude and as a result the natural or forced convective cooling ability of the air is less at high altitude than it is at low altitude Overheating problems of this type were originally experienced with avionics equipment in jet fighters in WWII The following worked example showing how hot something convectively cooled will operate at 15 000 feet compared to how hot it will operate at approximately sea level Example The product contains heat producing FET device with a convective cooling heatsink attached The product is operated at room temperature in Michigan elevation approximately 600 feet with a thermal couple attached to the The stabilized temperature of the FET is 50 degrees C after several hours of operation This product will be located within the passenger compartment heated to room temperature We are looking for answers to the following two questions What will be the temperature of this device when operated within the vehicle at 15 000 feet Driving along Skyline Drive on
225. erature And Vibration Long chains of repeated molecule units known as mers characterize polymeric materials These long chains intertwine to form the bulk of the plastic The nature by which the chains intertwine determine the plastic s macroscopic properties Typically the polymer chain orientations are random and give the plastic an amorphous structure Amorphous plastics good impact strength and toughness Examples include acrylonitrile butadiene styrene ABS styrene acrylonitrile copolymer SAN polyvinyl chloride PVC GENERAL MOTORS CORPORATION EDSON 2008 220 221 polycarbonate PC and polystyrene PS If instead the polymer chains take an orderly densely packed arrangement the plastic is said to be crystalline Such plastics share many properties with crystals and typically will have lower elongation and flexibility than amorphous plastics Examples of crystalline plastics include acetal polyamide PA nylon polyethylene polypropylene PP polyester PET PBT and polyphenylene sulfide PPS Most plastics can be classified as either thermoplastic or thermoset a label which describes the strength of the bonds between adjacent polymer chains within the structure In thermoplastics the polymer chains are only weakly bonded van der Waals forces The chains are free to slide past one another when sufficient thermal energy is supplied making the plastic formable a
226. erformed to understand and develop robustness to the stresses of temperature and vibration This is a Qualitative Test and will take the product way beyond specification to develop understanding of design margins Purpose The HALT test is not a pass or fai test but rather a qualitative quick learning method to identify product weaknesses or operating limits from vibration and temperature Locations of Applicability All locations This test method is most applicable to electronics and devices with circuit boards This is not intended to be a structures test for larger mass devices Procedure The complete HALT process procedure is explained in detail in GMW8287 Monitoring To be monitored continuously during the test Operating Type GENERAL MOTORS CORPORATION EDSON 2008 Operating type is 3 2 Criteria The FSC code for this test is not applicable The HALT test is not a pass fail test but rather a qualitative quick learning method to identify product weaknesses or operating limits from vibration and temperature The extreme levels of stresses applied in this test will evaluate design margin for hardware and will bring forth errors software hardware interaction as component values change with temperature and stress Software hardware interaction problems at temperature extremes are expected to be resolved Resolution of product improvement will be arrived at jointly through
227. ess also triggers a diagnostics counter that documents the number of COP triggered resets over a specified number of system power up activation cycles Preparation This procedure only applies to devices with digital processors Prior to performing this procedure a design review of the hardware and software of the supervisor system is to be performed with GM to ensure the basic design is correctly implemented NOTE It is unacceptable for both the SOH positive going Low High and negative going High Low pulse events to be triggered by the same subroutine called from the same software structure Achieving comprehensive processor and programming SOH coverage requires that one side of the SOH Signal is called from the main programming or operating system loop and the reciprocating signal is called from an a interrupt triggered routine Test Set up The test procedure requires one production intent device a system simulator and an oscilloscope monitoring the device s internal supervisor circuit stimulation input and reset trigger output signals These are monitored for each processor element Micro controller Microprocessor Digital Signal Processor DSP Display processor etc included in the EE Device For each processing unit in the device perform the following prepare and load programming with test code that can be triggered by an operator command to separately disable each software handshaking element of the SOH stimulation signal GE
228. essed in GMW3172 They are Thermal fatigue expansion and contraction Vibration Fatigue road induced vehicle vibration Fretting Corrosion in Bused Electrical Centers can be used for other applications where connection quality is a concern Most of the tests have empirically evolved based on the ability of each test to distinguish good designs from bad designs Some of the tests are used as pre treatments to uncover weaknesses from interactions between different types of stress Other tests are used as detection processes to place the product into a detectable state to reveal failure resulting from prior tests These concepts form the basis of the Test Flow provided in GMW3172 The test flow will be discussed in detail later in this document but let s consider an example to clarify our point We use the 500 or 2000 hour high temperature test aS a precursor to the mechanical shock test because the time at high temperature has the potential to create Kirkendall voids at the interface of copper traces and solder attachments These voids then represent significant points of weakness when the product is subjected to Mechanical Shock If these tests were not sequenced in this order then this major weakness could not be detected The one hour vibration test with a single thermal cycle is a detection test following the thermal fatigue test duo of Thermal Shock and PTC Failures produced during thermal fatigue may only become detectable
229. evice into logical functional subsystems of related inputs and outputs This may include I O that is internal to the device and does not directly connect to the vehicle The supplier shall develop a detailed test script that shall be in the form of a table or matrix that contains a section for each function with a sectional line item for each disruptive event applied to each I O relevant to the function Space shall be reserved on each line to document the system response to each disruption injection and if the response is acceptable or if stability improvements are needed Detailed software test scripts that determine the sequence of which I O shall be disrupted during which phases of functional operation may also be required for complex systems Special attention shall be given to dynamic sequences with position feedback and or timing critical signals The test plan is to be reviewed and approved by the GM Product Development Team When function critical parameters come from digital values delivered over a data link the denial or disruption of this data shall also be included as line items in the fault tolerance evaluation plan Test Set Up The procedure requires one production intent device a system simulator and a breakout box that allows each signal to be shorted to ground shorted to its supply voltage or battery voltage and open circuited A data link simulator with the data stream controllable by the tester is also required when c
230. evice where the components plastic materials media may be adversely affected by the continual production of contained heat Locations of Applicability locations where heat be produced within the device Procedure Monitoring The operating stabilization temperatures are to be monitored during the test Operating Type The operating type shall be 3 2 Temperature measurements with thermocoupling are used to locate and visualize the DUT hot spots Apply thermocouple near suspected hot spots and operate the device at maximum heat generating conditions 189 GENERAL MOTORS CORPORATION EDSON 2008 but within bounds of the specification per GMW3172 Quantify temperatures and evaluate design margin Criteria The temperatures reached under the conditions identified in the procedure must be less than the maximum permissible for the components involved with an additional level of design margin to insure reliable function over time The level of design margin necessary must be agreed upon with General Motors FSC A Infrared Imaging Method Purpose These methods may be used to enhance or replace the thermocouple methods Infrared Thermography is used to locate and visualize the DUT hot spots during function and short circuit conditions Locations of Applicability Al locations where heat may be produced within the device Procedure Monitoring The operating stabilizatio
231. ew 2 should occur within the Design Solution Peer Review Design Review 3 should occur within the First Hardware Peer Review Design Review 4 Should occur within the Production Should occur less formally between the Validation Engineer the DRE and the Supplier The outcome of the Design Review may redirect planned activity for the next phase of the ADV Process be flexible Design and Test Peer Review other Reliability Design Reviews A Moment For Humor A balloonist arranges for transportation for himself and his balloon to a precise place After flying for some time he realizes he s lost He reduces height and calls to a man on the ground Excuse me I was supposed to meet a friend half an hour ago but I m not sure of my location The man on the ground says You are in a hot air balloon hovering approximately 30 feet above this field You are between 40 and 42 degrees north latitude and between 58 and 60 degrees west longitude You must be an engineer the balloonist says in frustration Yes Iam replies the man How did you know Everything you have told me is correct but you haven t really helped me in fact I am still lost man on the ground says You must be a manager Yes Iam replies the balloonist How did you know You don t know where you are where you re going or how to keep your promises and after one question it s all
232. eyy 10 uonensuowag i 17 Seah OL 46 5 trh 42844 uonnioA3 Geb 199A AN 2 5 5155 ssaujsmmqug uj oj Auunjyioddgo ux 17 13 1 0G pue Ageda y uiseag uj JS ainsug oL SJUSAZ 22115 aly PUY AC JO SANA JON 5900 MOPUIAA Sul AQ SUL 0 4 Jepun JonpoiJd JO 212 2 GENERAL MOTORS CORPORATION EDSON 2008 127 THE TEST FLOWS EXPLAINED Let s Talk About The Test Flow The following Universal Durability Test Flows are designed to segregate failure mechanisms into individual test legs while allowing interactions between stress types that produce synergistic failures The sequence in test legs 1 through 5 is critical and every effort has been made to produce as lean of a test plan as possible Test Leg O TIME AT HIGH TEMPERATURE This test leg exists for leaded solder products only allowing reduced overall test time when compared to lead free solder by placing the time at high temperature test in a parallel test leg Test Leg 1 CRASH LEVEL MECHANICAL SHOCK Test leg one separates the extreme forces result
233. f these tests which is not shown in the following table When choosing the Z code you must understand fully why or why not each test is necessary You must also document your use of the Z code with a full explanation of your combination of each of the tests shown below Table 5 Code Letter for Climatic Loads Minimum High Number Moisture Temp Of Water Cyclic Constant Susceptibility Durability Thermal Splash Humidity Humidity Test Hours Shock Cycles eee ee Sears a IMEEM NR eee GENERAL MOTORS CORPORATION EDSON 2008 106 High Number Temp Of Cyclic Constant Durability Thermal Humidity Humidity Hours Shock Cycles Moisture Susceptibility Test YES YES YES YES YES As Agreed Upon Note Xenon Arc or outdoor sun testing is to be specified by the material engineer and no details for this type of testing are included in GMW3172 CODE LETTER FOR CHEMICAL LOADS AND UV TESTING The Code Letter for Chemical Loads and UV Testing In the past we required certain chemicals be applied to the product using different methods of application as defined in GMW3172 We also required Xenon Arc Weatherometer testing for colorfastness and resistance to UV degradation This was in addition to the requirements defined by the Materials Department This often put GMW3172 into conflict with the Specifi
234. failure following the preconditioning process as noted above Thermal cycling is generally conducted using a linear ramp thermal cycle from ambient to peak temperature occurring within three minutes This is followed by a two minute cool down back to ambient temperature This test is conducted using in situ electrical resistance heating of the IST coupon to peak temperature Fans cool the coupon using ambient air following the heating process Recent studies using an elevated temperature beyond the Tg of the laminate material have proven very effective in reducing test time and this elevated temperature method is well correlated to normal field use with the Inverse Power model 5 System Heated IST test coupon Plated through hole showing plating failures failures identified IST red testing GENERAL MOTORS CORPORATION EDSON 2008 HALT HIGHLY ACCELERATED LIFE TESTING HALT is a type of qualitative test that uses high rates of all axis random vibration with extremely fast thermal ramp rates HALT testing refers to tests performed in a HALT chamber a specialized testing system that can apply thermal change and vibration simultaneously The HALT test can be carried out in one to two days time euggested HALT OCese AN 4202 Vibration Stepping With Temperature Step stressing Vibration Swinqs Simultaneously Constant Room Tmax ie ee S in Temperature Tmax Step stressing Temperature
235. following graph and table provide the starting point of defining the level of field damage expected for thermal fatigue Conditions for Minnesota and Arizona are compared The Arizona conditions define the more severe user and Miner s Rule was used to assemble the different delta T values for each month in Arizona into a single delta T value for testing The origin of the field based temperature range for interior underhood and on engine thermal cycling testing is a technical SAE paper written by Jimmy M Hu and Ken Salisbury of Ford Motor Company The title of the technical paper is Temperature Spectrums Of An Automotive Environment For Fatique Reliability Analysis following two graphics are from that Ford SAE paper Explanation of the table and graph below The thermal range experienced in the field is different for different months of the year We can use Miner s Rule to combine all of the damage from the different months into a single test with a constant thermal range The damage model used with Miner s Rule to perform this damage accumulation calculation relies upon the Coffin Manson exponent for the type of material being stressed We are applying our thermal fatigue to solder as the natural weak link in the system The exponent for leaded or lead free solder is in the range of 2 5 to 2 65 Modified Norris Landzberg Equation for lead free solder 1 2 65 136 1 T Dwell tim 2185x 2 273 AF A test i Cres
236. g This test quantifies the possibility of breakdown of insulation in such applications High voltage potentials could exist in inductive devices with high step up transformers high voltage battery systems or within components connected to such inductive or high voltage devices A detailed analysis during test planning must be performed to determine which GENERAL MOTORS CORPORATION EDSON 2008 inputs outputs should tested and at what voltage levels The DUT be performing this test damaged Locations of Applicability All locations Procedure Monitoring Evaluate for arching during the test or puncture of the insulator material at the end of the test Operating Type The test shall be performed under operating type 1 1 1 Heat the DUT to stabilization at 35 C and 50 relative humidity 2 Apply a test voltage of 500 Volts alternating current with a frequency of 50 Hz to 60 Hz Apply this stress for a duration of 2 s to the DUT as follows Between electrically isolated and adjacent terminals Between electrically isolated terminals and electrically isolated metal housing Between electrically isolated terminals and electrode wrapped around the housing i e metal foil sphere bath in the case of plastic material housing Criteria There shall be no puncture or arcing through the insulator The FSC code is not applicable to this test Copper wire
237. g 5 Leg 7 Initial Initial VLA Temp Temp Volts Para Volts Para Eval Para Eval Eval Initial Temp Volts Para Eval Room Temp Unom Volts Para Eval Initial Temp Volts Para Eval 100 G Moisture Mech HIS Sen m a n Humidity 1 Shock bilit 25 G Mech PTC Fretting 3 Shocks Corrosion GENERAL MOTORS CORPORATION EDSON 2008 138 139 Test Leg Optional 40 G Mech Shock Closure Slam Test Vibration With Thermal Volts Para Eval Initial Temp Volts Para Para Eval Eval 100 2000 Shock 9 25 Mech Shocks Optional Temp Volts Shock Closure Slam Test Vibration With Thermal Volts Para Eval Volts Para Eval Cyclic Or Constant Humidity Testing Dust Detection Vibration with Thermal Testing Water Post Post Temp Temp Volts Volts Para Eval Para Eval Initial Temp Volts Para Eval Salt 2 T Corrosion 4 Testing Dust Initial Temp Volts Para Eval Thermal Shock Cyclic Or Constant Humidity Detection Vibration with Thermal Testing Water Post Post Temp Temp Volts Volts Para Eval Para Eval N AO A Initial Temp Volts Para Eval Moisture Suscepti 0 bilit GENERAL MOTORS CORPORATION EDSON 2008 ISO 8820 Over Current Humidity Fretting Corrosion ISO 8820 Over Current Engine M
238. g graphic 100 SnPb outperforms Pb free Pb free SnAgCu Strain 10 100 1000 10000 100000 2 Mean cycles to failure Circuit boards that have a high thermal mass resulting from the use of large components may require additional time at high temperature to ensure proper wetting during soldering of components to the circuit board This means that small components may reach temperatures in excess of 260 C which surpasses the rating of some critical components The following are examples of components that may be most at risk Aluminum electrolytic capacitors which can suffer dielectric cracking at temperatures greater than 245 C Large plastic ball grid array packages which are prone to warping at higher temperatures Warping results in weak solder joints anywhere on the ball grid array Expansion of the circuit board that is perpendicular to the surface of the circuit board can result in weakened or cracked plated through hole VIAs as is shown below Cracks In The VIA Barrel GENERAL MOTORS CORPORATION EDSON 2008 42 Elevated temperatures can also result blistering delamination warping in the base circuit board Circuit boards with higher glass transition temperature values may be required Lead Free Solder What Are The Sources Of Environmental Lead Electronics are not a major contributor to environmental lead Batteries 4 000 000 Tons but recycling is in plac
239. g is published by Amp Tyco Electronics Gold is an excellent electrical conductor and a highly stable noble metal which exhibits the following contact properties 1 Gold coatings are recommended for high reliability applications 2 Gold coatings can be used in corrosive environments 3 Gold coatings can be used for high durability 4 Gold coatings can be used with low normal force 10 to 20 grams and low wipe action less than 25 mm 5 Thin gold coatings 03 microns to 2 5 microns can establish a stable low resistance contact 6 Gold is not susceptible to fretting degradation However it can be worn away resulting in problems with the underlying parent metal 7 Gold contact performance can be enhanced with lubrication 8 Gold coatings require the use of a suitable underlayer such as nickel The nickel underlayer provides the following a Pore corrosion inhibitor b Corrosion Creep inhibitor c Diffusion barrier d Mechanical support for contacting surfaces 9 Gold coating thickness depends on application requirements following approximate cycles to failure wear through of hard gold over thick nickel underplate with 100 grams of normal force a 4 microns of gold 200 cycles to failure b 8 microns of gold 1000 cycles to failure c 1 3 microns of gold 2000 cycles to failure 10 Gold can be used for low level circuit conditions GENERAL MOTORS CORPORATION EDSON 2008 36 3
240. gation through the entire test duration occurs and the length exceeds the criteria Rapid propagation is defined as observable crack growth beyond index in each consecutive inspection until end of test Crack Spot Weld Durability Occurrence of crack detectable by unaided visual inspection in or at the circumference of a spot weld spot weld separated through the weld fused area spot weld nugget pulled from one of the welded parts or any separation or crack in MIG welded parts Strength Occurrence of a spot weld separated through the weld fused area spot weld nugget pulled from one of the welded parts or any separation crack the MIG welded parts Note that separation of greater than 20 in a spot weld grouping is to be documented For additional information regarding spot weld groupings reference GM Engineering Standard Automotive Resistance Spot Welds GM4488M Crack Forgings Castings Durability The occurrence of crack longer than 1mm Strength The occurrence of a crack in Cast or Forged Components Note that crack lengths longer than 1mm may be acceptable based on the function critical non critical material properties and cross sectional area of the part Crack Tear Polymer Composite Cosmetic Surfaces Occurrence of a crack tear detectable by unaided visual inspection on cosmetic surfaces Structural Components The occurrence of crack tear detectable by unaided visual inspection in the structure
241. gh efficiency Validation This method is now being used to evaluate the brush life in electric motors and is also explained GMW8758 Multi Stress Degradation Analysis Explained Normal Medium Stress Lower Stress High Stress stress A B Modeling Change From Stress to Stress amp Specification Normal Stress Level When will this E line cross the Each group of lines 15 a different specification stress level and each stress 15 line replicated with sample size Time or Cycles Figure 9 Degradation Analysis Explained GENERAL MOTORS CORPORATION EDSON 2008 70 71 NOMOGRAPH RELIABILITY AND CONFIDENCE LEVELS DEMONSTRATED BY 5 17 N 1 V e 1 2 c L 2 s t BILITY ZZ ee E ee 2 RELIA EU __ n e pe en 1 1 N 1 a a Vol 74 No 3 Juty 1982 y Scales Transpose K H GENERAL MOTORS CORPORATION EDSON 2008 INTRODUCING LEAD FREE COMPONENTS INTO A LEADED ASSEMBLY The following provides direction to the supplier as to what is necessary when lead free pre tinned parts are introduced into a circuit board assembly process that uses a tin lead solder Assumptions
242. ght then vibration testing may be required If there Significant changes that reduce the support of the circuit board then vibration testing may be required e If a different component is being used and has never been used previously then humidity testing may be required The humidity test is required because of concern for the permeability of water vapor through the plastic encapsulation If a different component is being used on this circuit board but has been used in a previously validated product then humidity testing may not be necessary When a change replaces a part with a near identical part in terms of size and mass then some of the electrical tests should still be run even though the environmental tests are not required Selected electrical tests should be run to ensure that the new part is as electrically robust as the old part Suggested electrical tests include but are not limited to may e Parasitic Current e Jump Start Reverse Polarity e Over Voltage Voltage Dropout e Superimposed Alternating Voltage Open Circuit Tests e Short Circuit Tests e Load Circuit Over Current Test EMC PRODUCT VALIDATION RESULTS REVIEW A PV results review should be performed on the results of the PV tasks with the intent of identifying if any issues remain and to identify whether there is for screening activity during start or product of this component Purpose Confirm that
243. haracterized Acceptable surface finishes and design rules to mitigate the risk of this failure mechanism are identified and discussed Finally some new corrosion test methods currently under development and their effectiveness are presented Solder Mask Cus 4 u p y a i JB 18 ANE FP Fur gf a ae 17 T ImAg Solder Mask ERY Copper Via Solder Mask NONE Solder Mask Solder Mask _Anin 8G Solder Mask L T T Figure 2 Typical creep corrosion photographs along f several soldermask encroached vias The ImAg finish naturally thins down beneath ith EDX apal 7515 Figure 7 Cross secto ges o the soldermask Copper is exposed at the base of this crevice and electrolyte ingress initiates the galvanic corrosion that forms CuS corrosion product which is seen to creep along the soldermask surface 49 GENERAL MOTORS CORPORATION EDSON 2008 ECONOMIC SELECTION OF LEAD FREE SOLDER L 7 J VJ aw E Rn Ce aes Best High P gt 2 2 y F Reliability Option E N SAC305 Appears Best Overall Sn Ag Bi May Be Worth Consideration Wher Pb Contamination Is No Longer An Issue Long Term Relative Costs Sn Po 21x a SAC305 2 15 7 2 a SAC405 2 35x The Above Information From Dr Ronald
244. hat you review the what is to be learned from the Analytical Task Checklist and ask the supplier when were you planning to learn this in the product development process Maybe you already know it can you show me evidence that you already know your design margins by presenting data The following graphic shows how one could build the reliability requirement into the design process by inclusion of a pre determined design margin corresponding to the reliability requirement How Can Affect Reliability During Analysis Designing With Adequate Design Margin To Accomplish The Reliability Objective Probability Plot 99 90 Weibull Data 1 oo 2 A RRX S F 1 S 0 10 00 5 00 97 Unreliability F t 1 00 10 00 1 00 yin Life Lives The design of a product that begins without adequate design margin can never be grown into a reliable product Learn early and learn at minimum cost DEVELOPMENT TASKS Development Tasks We all human beings and we all make mistakes but we are also able to learn from our mistakes We are unable to anticipate in our analysis those things that were never supposed to be We only learn these things from testing the actual product This is why we run Development Tasks to learn what we could not anticipate The Development Tasks will exercise the same failure mechanisms
245. he functional requirements are met while the DUTs are being exposed to the test environment Function is validated while the parts are exposed to the test environment by continuously monitoring and recording exceptions to all outputs both hardware and on vehicle communications not being in the correct state for a given set of inputs and timing conditions Sampling on a frequent basis is an acceptable form of continuous monitoring The sampling rate shall be reviewed with and approved by Validation Engineering If available also Data from internal diagnostic systems shall be used and recorded DIMENSIONAL The Dimensional Test shall performed at room temperature after the product has been pre treated with 2 hours at Tmax Tmax rps whichever is greater Al dimensional physical requirements including labels on the GM released drawing shall validated documented unless indicated otherwise by GM Engineering Any Dimensional Test results that do not meet the part drawing requirements shall be considered validation nonconformance issue GENERAL MOTORS CORPORATION EDSON 2008 170 171 VISUAL DEVICE INSPECTION AND DISSECTION The visual inspection and dissection takes ona high degree of importance with the introduction of lead free solder The use of lead free solder requires that we now look for tin whisker formation and excessive void formation in solder joints The inspe
246. he test was suspended after four failures then you will use the first four median rank values out of a sample size of six 277 GENERAL MOTORS CORPORATION EDSON 2008 Oveanow fe wn pe t p Table 35 Median Ranks For Weibull Plotting 1 50 000 29 289 20 630 70 T11 59 000 792370 11 6 107 144796 23 578 324 380 41 189 50 000 584 811 67 620 76 421 85 204 93 893 2 12 52613 134598 21 669 294758 372853 45 951 54 049 622147 70 242 784331 86 402 94 387 3 13 5 192 12 579 202045 27 528 354 016 422508 502000 572492 642984 72 4912 79 955 87 421 946 808 MEDIAN RANKS SAMPLE SIZE 4 154 910 38 573 61 427 84 090 5 122945 31 381 50 000 682619 87 055 6 104910 26 445 4246141 5726859 734 555 89 090 MEDIAN RANKS SAMPLE SIZE 14 4 8230 114702 185 647 254 608 32 575 39 5454 46 515 53 485 602456 674425 740392 8164353 884 298 956169 15 4 516 102940 17 432 236 939 304452 36 967 6344823 50 000 56 517 63 033 694548 76 4061 82 568 89 060 955 484 16 42240 10 270 162365 22 474 284589 346 705 402823 46 941 53 059 59 177 654295 71 411 776525 83 635 89 7230 95 760 7 92428 222849 36 e412 50 000 634588 772151 90 572 17 32995 9 678 156 422 21 2178 262940 324704 38 469 444234 50 000 55 766 614531 67 296 734060 784821 84 578 904322 962005 8e300 20 113 32 052 44 015 556 98
247. hes of the road and may be submerged or excessively splashed when the vehicle is used This test is also required of any potted device located any where on the vehicle The Seal Test may also be required as an additional in combination with the high pressure wash test 9K This combination would be appropriate for low mounted devices under the hood of the vehicle Sugar Water Function Impairment This is a new test that replaces many of the fluid compatibility tests of the past The Material Specifications originating from the Materials Department should cover the material tests for fluid compatibility This Sugar Water Test should be used when there are moving knobs or sliders such that the drying of the sugar solution may result in sticking or poor feel Not needed if there are no moving parts Chemical Loads Tests Chemical Loads Materials Testing and UV Testing M You must work with the Materials Engineer to ensure that these tests which are the responsibility of the Materials Department are planned and executed properly DV Results Review GENERAL MOTORS CORPORATION EDSON 2008 154 Procedure Results Review of Design Validation Tasks Essential activity in preparation for PV Test Planning Visual inspection and dissection is a natural part of this process 199 GMW3172 A D V TASK CHECKLIST PRODUCT VALIDATION PROCEDURES The following flow chart should provide a baseline of guidanc
248. his test evaluates the robustness of the interconnecting ground trace on the circuit board between grounding pins when subjected to over current conditions that may occur when one of the ground paths is disconnected from ground and shorted to battery Generally one of the ground pins on the back of the device connects to ground and the other ground pin connects to a wire that is providing a ground for another device It is this ground pin for the other device that will be shorted to battery voltage in this test GENERAL MOTORS CORPORATION EDSON 2008 Locations of Applicability locations feature exists but only where the Procedure Monitoring Proper function is not expected during shorting Monitor for overheating during and after test Operating Type The test shall be performed under operating type 3 2 loads on 1 This test is to be run under room temperature conditions using Umax voltage and a fuse of the intended size If the intended size is not known then use a 20 amp fuse 2 Use an adequate length of wire from the device to the ground to produce 35 milliohms of resistance in the ground path 3 Apply Umax to the other interconnected ground pin for as long as is necessary to allow the 20 amp fuse to open 4 Remove the Umax voltage and evaluate visually and electrically the interconnecting circuit board trace for damage Criteria Functional Status shall be class C There shall
249. hiskers The tin in an effort to relieve the stress displaces material by spontaneously exuding tin whiskers from the surface of the tin The tin whiskers may short between leads or break off and generate electrical faults in other areas of the circuit board There is a growing list of field failures resulting GENERAL MOTORS CORPORATION EDSON 2008 from tin whisker formation It does not require special or stressful conditions for the whiskers to form They will easily form while the part is sitting on your desk or is placed in storage through the Service Parts Organization SPO ae 12 2 Tin Whisker Tin Whiskers In The Space Shuttle Flight Controls 1975 1984 Acceptable Component Finishes The portion of the component lead which is not embedded in the attaching solder is most at risk for tin whisker formation These areas of the component retain the same metallurgy as when they were pre tinning by the component supplier Different finishes have Significantly different probabilities of forming tin whiskers over extended periods of time The following table from iNEMI divides the probability of tin whisker formation into 3 categories Category 1 represents the lowest probability of tin whisker formation and category 3 presents the greatest probability of tin whisker formation The different finishes shown along the left column are color coded into four groupings those at the top in green and blue represent the least probl
250. ial that is used to bond the dissimilar materials together This problem would not occur if the dissimilar materials had the same coefficient of thermal expansion CTE The effect of thermal cycling will have differing levels of severity depending upon the S N slope of the material being stressed In the following example a device contains a stretched copper wire that is attached by a solder joint At the normal range of thermal cycling 43 for an interior device both the solder and the copper have the same life However during testing we increase the stress by increasing the range of thermal cycling 125 C is typical for an interior device The increased stress is used to accelerate the test but the steeper slope of the S N line for copper results in the failure of the copper before the solder Thermal cycling has a more profound effect upon the copper than the solder because of the difference in the slopes of the two S N lines In this example if the copper fails first then you should back calculate to determine if the copper would have failed before the requirement at normal stress Life 2_ Life normal _ accelerated A normal Note the m value for copper is 5 GENERAL MOTORS CORPORATION EDSON 2008 240 241 If the copper would have failed before the requirement at normal stress then engineering action should be directed at the copper by adding a compliance loop in the wire If the copper would n
251. iation between a strong sample of the part and a weak sample of the part How can samples have variation in strength Small variations that result in stress risers will significantly reduce fatigue life We can never escape the fact that there will be variation in stress and variation in strength The interference between these two distributions represents the un reliability of Our product in the customer s hands Ideally we would like no interference giving us a reliability of 100 Because each distribution has a long and theoretically infinite tail we can never achieve a reliability of 100 We select a reliability requirement that meets a predetermined objective The following graphic portrays this relationship The Basic Concept of Stress Strength Non Interference The Word Strength Is Generic And Can Hepresent Many Forms Of Resistance To Stress The World Product Of Stress Strength Product Strength Reduced From Fatigue Am The Extreme User The World Of Stress Movement Over Time We realize that we must satisfy the severe user in addition to the average user In fact certain areas of the country such as Phoenix Arizona are completely filled with severe users in terms of high temperatures We therefore define our lab test based on the 99 8 severe user only 2 people out of 1000 will be more severe to ensure that all customers are accounted for The process of quantifying the severe is non trivia
252. ic Shaker DEMONSTRATING RELIABILITY FOR ROBUSTNESS TO VIBRATION The engine is the worst place you could ever mount something when it comes to vibration The stress levels are the greatest and the test time is the longest Do not mount electronics on the engine if possible Remember a sprung mass location is either the body or the chassis An un sprung mass is located on the suspension members or the wheel tire knuckle assembly When something is to be mounted in a location other than on the engine you must decide whether this application should really be called a truck or a car SUVs and crossover vehicles should be considered Cars when it comes to vibration The increased duration of vibration testing for a truck is the result of PUMA data showing that a GENERAL MOTORS CORPORATION EDSON 2008 222 commercial semi commercial duty vehicle sees more damaging use per mile than does a vehicle that would be family owned and driven These vibration tests have been developed to encompass the worst of the worst in terms of global use These tests will accommodate all mileage requirements from 100 000 miles to 200 000 miles without need for adjustment in stress level of test duration Adjustments in test duration may be necessary to accommodate statistically induced effects when smaller sample sizes are used The baseline test durations that would be used if 23 parts were tested R 97 and C 50 are as follows Table 20 Bas
253. ications Flux residues from lead free solder may be more inclined to produce ionic contamination when compared to lead based fluxes and special attention should be given to the frost and humidity testing of lead free solder assemblies Lead contamination in lead free solder processes leads to intermetallic formations resulting in further reduction of fatigue life of solder joints Therefore the mixing of leaded and lead free technologies on the same circuit board or within the same manufacturing environment should be avoided but is not forbidden The use of lead free components soldered onto a circuit board with leaded solder generally does not create a problem notable exception occurs when bismuth Bi is involved Bismuth tin can be used as the tinning material for components and can be used for component attachment to circuit boards addition of bismuth in the tin alloy for circuit fabrication has the advantage of a reduced melting point thus reducing the temperature that the components will experience However bismuth combines with lead and tin to form a ternary phase material with a very low melting point of only 969C This low melting point material is formed at attachment points and represents a significant risk for automotive applications The addition of bismuth is also discouraged because it is a by product of the lead mining industry A detrimental tin based phenomenon known as Tin Whisker Formation is most
254. ice as in vehicle assembly or servicing Procedure Method A Monitoring Monitor clearances to critical components on the circuit board The circuit board should not be deflected Operating Type The test shall be performed under operating type 1 1 The shall withstand without electrical degradation or permanent physical damage a simulated e bow load of 110 N The DUT shall be set up to allow testing on all external surfaces with a 13 0 mm or larger diameter area Subject the DUT to an evenly distributed 110 N force about any 13 0 mm diameter area for 1 0 s this represents the force applied by a person s elbow Functional and Parametric Test shall be performed at the end of test Criteria The device should function properly following the application of the above stress levels physical damage Should be evident which may lead to subsequent failure with vibration induced stresses Functional Status Classification C Method B Locations of Applicability All areas of the vehicle where a person may stand upon the device during vehicle assembly or servicing Monitoring Monitor clearances to critical components on the circuit board The circuit board should not be deflected Operating Type The test shall be performed under operating type 1 1 Functional Status Classification C The shall withstand without electrical degradation or permanent physical damage a simula
255. icult to hear any squeaks or rattles Purpose The DUT should be checked prior to and following the vibration test to ensure that no objectionable squeaks or rattles are present or develop as a result of the test Procedure Monitoring Monitor for objectionable squeaks and rattles during the time that a vibration input is provided Operating Type Not Applicable Squeak and rattle evaluation prior to vibration testing The squeak and rattle assessment can be made by Shaking the parts by hand or by reducing the vibration level to 5 Grms using the same PSD signature and performing a simple listening test Squeak and rattle evaluation following the vibration testing These same procedures can be used at the end of the vibration test to evaluate squeaks and rattles Alternatively critical test GMN14011 can be used for devices when repeatability and quantitative measurement are important Criteria No objectionable squeaks or rattles Should be present before or after the vibration test When GMN14011 is used to evaluate squeaks and rattles then the requirements for this test must be defined in the CTS The responsible GM engineer should evaluate the severity of all squeaks and rattles that develop following the vibration test The criteria for a mounting location that is close to the passenger s ears should be more discriminating than for locations farther away The FSC code is not appli
256. idity tests After completion of the Humidity tests the remaining thermal cycles shall be completed using the combination of thermal shock and PTC as shown above 245 GENERAL MOTORS CORPORATION EDSON 2008 THERMAL SHOCK AIR TO AIR TS Air to Air Thermal Shock is used as a fast method to produce thermal fatigue in solder joints or circuit board structure There is no real acceleration factor when this test is applied to lead free solder other than the basic increase in the number of thermal cycles that can be produced per unit of time We try to produce 75 of the required total damage with thermal shock and the remaining damage with PTC testing While the increased ramp rates shorten the duration to reach from one temperature to the other the dwell periods should still remain at 10 minutes hot and 10 minutes cold as is specified for PTC testing A single product must be thermocoupled as pre test assessment to determine the thermal lag time resulting from thermal mass The thermal lag time is added to the dwell period to ensure that the product is within 3 C of the target temperature when the dwell period begins Purpose This is an accelerated test to evaluate failure modes driven by mismatches in the coefficients of thermal expansion between components circuit boards under conditions of temperature change Locations of Applicability This test applies to all areas of the vehicle Procedure
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258. ile Product Is Off Asleep One Minute Good Objective There Should Be No Change In Parasitic Current Resulting From A Lowering Of Supply Voltage 1 Volt 11 Minutes GENERAL MOTORS CORPORATION EDSON 2008 5 The test should be repeated for the various methods in which the DUT can enter the OFF Asleep state 6 This data will be used to calculate the average parasitic current experienced over a 40 day period Note Consider the fact that the product may draw different levels of current under conditions of varying temperature If you believe that your product may be sensitive to this phenomenon then these measurements should also be taken at temperature extremes Criteria average parasitic current should be calculated as the average current flow over a 40 period maximum allowable average parasitic current shall be 0 250 mA if not provided in the CTS The test report must include the following information 1 Parasitic current draw when in the OFF Asleep state 2 Parasitic current draw under all OFF Awake conditions and their time period 3 Calculated average parasitic current draw over 40 days 4 Parasitic current over the voltage range from 12 down to 1 volt FSC code is not applicable to this test RESET BEHAVIOR AT VOLTAGE DROP The Voltage Drop Test is looking for the misbehavior of smart devices when there are momentary
259. ility Applicable to all devices in the vehicle Procedure Quantify the resonant frequency of the circuit board either by formal modal analysis or through the more simple models provided reference 1 Steinberg Criteria resonant frequency of the circuit board must be greater than 150 Hz Low resonant frequencies represent increasing risk of fatigue failure from increased board displacement supplier must provide evidence of appropriate corrective action when the resonant frequency is below 150 Hz The corrective action is to be reviewed with the GM Validation Engineer GENERAL MOTORS CORPORATION EDSON 2008 160 161 HIGH ALTITUDE SHIPPING PRESSURE EFFECT ANALYSIS The High Altitude Shipping Pressure Effect Analysis is only required when there is significant risk of rupture of sealed devices from low external pressure occurring during air shipment in an un pressurized airplane cargo hold Devices with Gortex Vents are exempt from this analysis The following analysis compares the stress resulting from the pressure differential between the low external pressure 11 kpa and high 101 325 kpa internal pressure to the structural strength of the hermetically sealed cavity It is assume that the pressure was 101 325 Kpa standard atmospheric pressure at the moment the device was sealed Please use the appropriate value if a different level of pressure was present within the device at the
260. illusions are eventually replaced with a deeper understanding of reality The spirit of the boundary crosser glows brightly in the poems On Beyond Zebra by Theodor Seuss Geisel 1904 1991 and The Deacon s Masterpiece by Oliver Wendell Holmes 1809 1894 I hope your quest for developing reliable products is accompanied with the same degree of passion exemplified in these poems In The Beginning through to Z is for Zebra know them Said Conrad Cornelius o Donald o Dell all well My very young friend who is learning to Said Conrad Cornelius o Donald o Dell spell So now know everything anyone knows The A is for Ape And the B is for Bear From beginning to end From the start is for Camel is for Hare to the close M is for Mouse And the is for Because Z is as far as the alphabet Rat goes know all the twenty six letters like But then something happened that Dr Seuss Beyond Zebra GENERAL MOTORS CORPORATION EDSON 2008 THE QUICKSTART FLOWCHART You at The Start Identify where in the vehicle your product will be located Turn to table 1 and write down the code sequence that is suggested based upon the location of your product in the vehicle Working from left to right take each test category code letter turn to the appropriate table for that code letter and make sure this code letter properly desc
261. in Texas The significant and rapid changes required to eliminate lead from electronics in the short period of time required by Restriction of Hazardous Substance ROHS legislation was likely to result in new quality and reliability issues The industry had been using the same materials for over 50 years with much data and experience to guide in the creation of design rules manufacturing processes appropriate reliability test methods and in predicting failure mechanisms Changing the solder alloy and its material properties the fluxes termination plating materials PCB surface finishes and soldering temperatures in a span of 1 2 years was a high risk undertaking many in the industry predicted dire consequences Indeed many new failure mechanisms were detected in Dell s reliability testing and actions were taken to prevent these failures from occurring in the field Product quality data shows this was an overall success However one new failure mechanism was not foreseen by Dell or the industry Immersion silver ImAg was widely adopted to replace hot air solder level HASL as the surface finish on PCBs ImAg was known to tarnish but it was a surprise to find that it suffered creep corrosion when exposed to high sulfur and humid environments Failures could occur in as little as a few weeks in industries such as rubber manufacturing water treatment paper mills or fertilizer production to name a few The failure mechanism has been well c
262. in GMW3059 is as follows We believe that the European Union will meet in the fall of 2007 and will eliminate the current 60 gram exemption for lead on circuit boards for automotive electronics A grace period will be provided The best estimate of the final ruling is that all circuit boards including carryover products will need to be lead free by 2010 The following words from Ben Baker and Doris L Hill should help clarify the situation Doris Requirements and Compliance Strategy The EU End of Life Vehicle Directive requires the elimination of Lead Mercury Hexavalent Chromium and Cadmium The timeline compliance is material specific so elimination of these chemicals started in July 2003 and will continue phasing out for the next 10 years Further certain materials have been granted temporary exemptions due to technology limitations thus a confusing landscape GM has internalized these requirements into GMW3059 GM s restricted and reportable substances for parts specification Our strategy is to segment the requirements so that we are doing one major push at a time for both domestic and export parts This allows both engineering and suppliers to focus on one set of applications at a time reducing confusion Our push on Hexavalent Chromium in corrosion preventative coatings started in 2000 and most work was done by early 2007 Our push on Lead in Bearings and Bushings and Lead in Aluminum started in early 2007 and will finish in
263. ing from a vehicle collision approx 35 mph from other cumulative failure mechanisms Failures in this test leg indicative of products that do not have adequate strength in their attachments Test Leg 2 POTHOLE MECHANICAL SHOCK AND VIBRATION FATIGUE This is the mechanical shock and vibration fatigue test leg The high temperature test has been placed at the beginning of this leg for lead free solder designs to screen for possible Kirkendall voiding problems unique to lead free solder If you are using a leaded solder device then the time at high temperature test can be placed in its own test leg O The sample size of 6 for vibration has been considered when establishing the 24 hours test duration in the 4 axis In the vibration test only the Z axis is defined as perpendicular to the circuit board and necessarily perpendicular to earth Good dissection at the end of this test is essential in identifying the onset buds of possible fatigue problems Test Leg 3 THERMAL FATIGUE AND WATER VAPOR INGRESS Test leg three is generally the GENERAL MOTORS CORPORATION EDSON 2008 128 129 longest duration test leg and the timing is primarily driven by the thermal fatigue testing composed of thermal shock followed by PTC It is a requirement to demonstrate reliability for thermal fatigue The number of thermal cycles along with the sample size is integral with the level of reliability bei
264. ion profile for these areas should be used instead of the Sprung mass as shown the Appendix O analysis Purpose Design reliability into the bracket by incorporating adequate design margin for vibration induced fatigue Locations of Applicability Applicable to all locations in the vehicle Procedure Follow the detailed steps as shown by example in Appendix O Criteria The design margin shall be large enough to meet the reliability Review table 37 for a description of how much design margin is required to meet the reliability requirement of 97 requirement CRUSH TEST ANALYSIS Purpose This analysis of the case is performed to ensure that elbow or foot loads on the case will not cause damage to components on the circuit board Locations of Applicability Applicable to locations in the vehicle where forces from assembly are possible This may include use as a rest supporting surface for other assembly operations Procedure Use finite element analysis to insure that the requirements for crush test GENERAL MOTORS CORPORATION EDSON 2008 as defined as physical test is met The intended load must be identified as stemming from a person s elbow or foot as described in the test portion for this concern Criteria The deflection of the device cover must not generate forces on components or the circuit board Additionally the deflection forces must not cause the cov
265. ipment is used for Product Validation then Sample Selection for Product Validation must follow GMN10066 Multi Vari Sample Selection Procedure for Product Validation Evaluation of Solder Repairs Selective Tests Performed Using Parts That Have Typical Manufacturing Repairs Vibration Shipping Evaluate the effectiveness of the packaging to protect the product from scuffing and damage Audit Screening Activity ESS or HASA Per GMW8287 High Frequency Audit During Production Startup Continuous Audit During Production 5 GMW8287 describes HALT testing and HASA ESS Screening Screening during production is intended to detect quality spills that develop during production Screening is intended to detect these quality spills prior to these problems being passed on to the customer and detected in warranty Startup screening may be required in situations where risk continues following Validation Screening may also be used with a supplier that is having difficulty maintaining product quality during startup Screening would taper off as the problems are resolved and production is brought under GENERAL MOTORS CORPORATION EDSON 2008 156 Product Validation PV Results Review Results Review of Product Validation Tasks The following PV Testing Decision Tree is intended to provide guidance for the transition between DV and PV This is not intended to be used for running changes during production PV Testing Decision T
266. is not a problem Procedure The effect of convective cooling is reduced as the air density decreases Air density is reduced as altitude is increased The appropriate multiplier as shown in the following table can account for this phenomenon The assumptions used to produce the multipliers are as follows heat transfer coefficient in a naturally cooled system can be expressed as a function of the Gashoff and Prandtl numbers The temperature and density dependence of the Grashoff number dictates the increase in case to ambient resistance and thus the increase in operating temperatures e Energy balance is used a forced air system and the air temperature rise is inversely proportional to the density of air e Power dissipation dominates the temperature rise in a high power fan cooling system The effect of air density variation on the Reynolds number accounts for the increase in case to ambient resistance which thus accounts for an increase in operating temperatures GENERAL MOTORS CORPORATION EDSON 2008 Altitude Multiplier Meter Fan Naturally Feet Cooled Cooled High Power Convection 8 4572 1 77 1 58 meters 15 000 ft Note The bolded value of 1 33 will be the most frequently used value in GM calculations The multipliers as noted are used to adjust the temperature rise for high altitude effects with the use of the following equation Where T altitude
267. itic Current Measurement Test This test is only required if you have a device that goes to sleep or operates ina sleep like state where less energy is required to sustain the product The test duration only needs to be long enough to capture the total wakeup event Different levels of wakeup may occur and all wakeup events over a 40 day period must be comprehended the final calculation of parasitic current This does not mean that the test needs to last 40 days The 40 days represents the maximum duration one would expect a person to be parked at the airport and is only used in the final analytical calculations Note The process of measuring the current while dropping the voltage as noted in step four is required to check for unexpected behavior as described by the following A vehicle is parked for a lengthy period of time at the airport and as the battery voltage drops below the point where the car could ever be started the very low battery voltage unexpectedly results in the waking of the module producing a continuous high current drain on the battery The battery becomes depleted to the point where recharging is not effective and the battery must be replaced The unexpected waking up should not occur and any form of unexpected high current draw at very low voltages should also not occur as it may result in the destruction of the battery Purpose Al of the functions that consume energ
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269. kel underplate Yellow Matte SnAg 1 5 4 w Nickel underplate SnCu w Nickel underplate Bright Tin w INickel underplate Matte SnBi 2 4 Bi Orange Matte SnAg 1 5 Ag Matte 5n no underplate Bright Tin 1 No tin whisker testing required 2 Finish must pass tin whisker testing 3 Do not accept in any case ba bo ri bo Color Coding for Table 2 Green Preferred finishes Blue Finishes with preferred tin whisker mitigation practices Finishes with tin mitigation practices that are less desirable than preferred practices Finishes without tin whisker mitigation that are often not acceptable to users Finishes to avoid Yellow GENERAL MOTORS CORPORATION EDSON 2008 78 79 Circuit Board Surface Finishes surface finish is applied to the copper traces and lands of the circuit board to prevent oxidation of these surfaces prior to circuit board assembly The formation of oxidation on the copper surface degrades the solderability of the surface The Hot Air Surface leveling HASL process using tin lead has been a successful and standard finish for the last 50 years The lead free initiative requires new surface finishes which do not contain lead These new finishes include Organic Surface Preservative OSP immersion gold over electroless nickel electroplated gold over electroplated nickel Pb free HASL immersion silver and immersion tin Immersion tin is susceptible to the formation of
270. ks required by GM may only be a subset of the total activity of the supplier However the ADV tasks required by GM have been well thought out and are very thorough in addressing well understood failure mechanisms and electrical performance criteria The ADV plan draws its requirements from several GMW document sources GMW3172 has become the cornerstone for electrical component validation plans Environmental testing and general electrical robustness evaluations are described with reference to international standards from the International Standards Organization ISO The activities that are described in GMW3172 have dramatically evolved over the last 10 years and now represent a good role model for a comprehensive specification GMW3097 defines the requirements for immunity and compatibility with radiated emissions The testing defined in this document is often expensive and requires several iterations to meet the requirements Attention should be focused early in the program to the needs of this specification GMW3431 defines the requirements for devices that contain switches that will be activated by human touch This document defines the requirements for mechanically cycling switches and draws heavily from the environmental tests defined in GMW3172 Devices with switches must have a test flow that encompasses the requirements of both GMW3172 GMW3431 Electrical devices that also contain a mechanical mechanism should be tested for envi
271. l Results Review Purpose Identify weaknesses or lack of design margin and initiate corrective action now A refocusing of attention during development or additional tests may result based upon the outcome of the analytical tasks Procedure Perform the review Appendix design per Criteria Initiate corrective action as early as possible in the product development cycle GENERAL MOTORS CORPORATION EDSON 2008 DEVELOPMENT AND EVALUATION ACTIVITIES These activities are designed to detect weaknesses or design oversights that were not comprehended during analysis or simply could not be evaluated during analysis The development activities are not intended to prove reliability but rather highlight outlier weaknesses that should be corrected prior to validation FUNCTIONAL AND DIMENSIONAL TESTS IN DEVELOPMENT MD Let s make sure that the product works at all temperatures and all voltages before we spend our hard earned money on durability tests This is the first long bar across the top of the test flow and combines the basic temperature voltage functional and parametric evaluation with an extended test time at cold to cover the wakeup Test All Possible Temperature Voltage Combinations All possible combinations are noted in the following table However an efficient subset of these combinations is defined below with the Five Point Evaluation GENERAL MOTORS CORPORATION EDSON
272. l and makes extensive use of PUMA data damage modeling and Weibull analysis GENERAL MOTORS CORPORATION EDSON 2008 86 The basic idea of how the extreme user is identified is shown the following graphic Identifying The Extreme User Usage of a product varies because people vary Some people will be easy on the product and some people will be hard on the product We statistically quantify the severe user by statistically extrapolating the usage pattern from a sample of people lt lt Derived Requirement Number Of Times A Product 7 Pd 4 Is Used C Most Severe Or The eee Observed In Our Level Of eU eem SIE ous Sample Force e ie Applied 5 Sampling period Time 10 Yrs Focusing On The Severe User FW Severe User Legend 2 Distribution of this U Average User Becomes a Our Test Frequency Nominal Design Point and Variation in Product Strength Stress or Strength Unreliability for the Severe User 87 GENERAL MOTORS CORPORATION EDSON 2008 We test as if the world was filled with nothing but severe users At first it may appear that we are trying to make life harder than is necessary but if we are clever we can turn this into a strategic advantage We can reduce our reliability requirement on test if we define our test in terms of the severe user Mathematical techniques allow us to
273. late the estimated total test time GENERAL MOTORS CORPORATION EDSON 2008 296 Appendix Values For m In Coffin Manson Equation ATem e Material Acceleration Factor seederatea ATemp Leaded Solder General Use normal 25 Lead Free Solder SAC Solder Studied by Hewlett Packard B Cu and Lead frame alloy TAB 2 7 wi bord Note The values shown 777481 wire bon represent the slope of the Au4AI fracture wire bonds Stress Life relationship 4 PQFP Delamination Bond failure for x ud a2 Copper xx slope values inherent Au wire Downbond heel crack with solder will assure 51 ASTM 6061 Aluminum alloy that adequate test 16 7 5 Alumina fracture bubble memory Suet though this represents Inter layer Dielectric cracking longer test duration than Silicon fracture would be necessary for the other material types Si fracture cratering Thin Film cracking 5 0 7 NJ e UI 00 D Note The values shown represent the slope of the Stress Life relationship line for each material The use of the shallower slope values inherent with solder will assure that adequate test duration is used even though this represents longer test duration than would be necessary for the other material types The following table identifies the engineers who over the years were responsible for empirically deriving the values for m UUL ee
274. le that have connection to the 12 volt wiring system GENERAL MOTORS CORPORATION EDSON 2008 174 175 Procedure Monitoring After the test Operating Type The test shall be performed under both operating types 3 1 loads off and again under 3 2 loads on Perform a Functional Parametric Test prior to application of each over voltage event e Connect the power supply to the battery inputs of the DUT and all loads that have battery inputs e Turn on the power supply subject the DUT to the required test voltage for the required test time as noted in the following table e Perform Functional Parametric Test at Unom Table 14 Over Voltage Test Test Voltage V Sweep between 16 and 18 at 1 volt per minute for 60 Test Time min devices that are over minutes voltage protected Provide a constant 18 volts when no over voltage protection is provided 60 minutes Criteria Functional status should be at minimum class C SHORT CIRCUIT TESTS The Short Circuit Tests are designed to evaluate the ability of an electronic device to survive and produce no hazard to the vehicle occupants when a_ short circuit condition occurs The short could be to ground to battery voltage or between other output lines combinations should be evaluated Devices that operate with Smart Protecton Circuits current sensing or temperature sensing should be evaluated using the follo
275. le Mechanical Shock Half Sine Collision Based Note The Three Body Mounted Regions Contain The Same Shock EN Impulse Value Of Peak G Times Duration of Car of Truck of Impacts P3 ey Impacts Per Impacts Per Es 5 i For Direction Direction Cars or Trucks Ionio 400 X 6 2400 mass Truck Un sprung 4200 X 6 25200 3X6 mass 18 187 GENERAL MOTORS CORPORATION EDSON 2008 Cars or Trucks Body Front amp Rear region C Cars or Trucks Body Middle region A Cars or Trucks Body Transition area region B Figure 20 100 G Mechanical Shock Test Device Door Trunk Hood Slam Purpose Special requirements for components mounted in closures door trunk lid hatchback and hood The purpose of this test is to determine if the DUT is able to meet specification requirements when subjected to the mechanical stresses defined below Locations of Applicability Required only for devices located in these closure areas 400 X 2400 4200 x 6 25200 10 400 X6 2400 4200 x 6 25200 10 200 25200 100 Procedure Monitoring Proper function is not expected during application of mechanical shock events The DUT is evaluated with monitoring at the end of the test operating 3 2 However devices that include relays such as wiper electronics and window modules Should be evaluated for proper function during the slam mechanical shock event ope
276. lead free solder changes many long established practices including the process parameters for solder repairs performed during the manufacturing process If the manufacturing process allows product to be repaired then Process Validation should include products that have been intentionally repaired using the established repair processes and equipment Approximately 20 of the PV samples should contain common solder repairs if solder repair is permitted The quality of solder repairs is of great concern with lead free solder GENERAL MOTORS CORPORATION EDSON 2008 VIBRATION SHIPPING The Vibration Shipping Test evaluates the ability of the packaging to protect the product from shipping damage prior to the product reaching the assembly line Close examination of the product following this test is critical in detecting damage both functional and cosmetic Purpose This test augments all previous vibration testing The shipping vibration test is intended to evaluate shipping container effectiveness in preventing damage during shipping by all forms of transportation Locations of Applicability locations Procedure Monitoring No monitoring occurs during the test Evaluation for damage only is performed at the end of the test Operating Type The operating type shall during the test be 1 1 The following is the same test as defined in GMW3431 The following shipping vibration profile is a
277. lement Ape Requirements description Testing may be conducted Not to evaluate overheating or protected malfunction from contamination Dust shall only penetrate in Dust quantities which do not protected impair performance and Safety Dust tight Dust shall not penetrate Second IP Code Element Water Second Degree of protection for Water Brief element Requirements description Not required None Test may be conducted to evaluate effect on Not protected performance 115 GENERAL MOTORS CORPORATION EDSON 2008 Second code element Degree of protection for Water Brief Requirements description q Water drips with Vertical drips shall not have any harmful effects enclosure inclined by 15 Water spray Splash water with increased pressure Strong high velocity water with increased pressure Seal Evaluation Continuous immersion in water Water during high when the enclosure is tilted at any angle up to 15 on either side of the vertical Water spray which sprays against the enclosure from any direction at a 60 angle shall not have any harmful effects Water which splashes against the enclosure from any direction with increased pressure shall not have any harmful effects Water which is directed against the enclosure from any direction as a strong jet with increased pressure shall not have any harmful effects Water shall not penetrate in a
278. lladium Diagram of the Fretting Corrosion Phenomenon Initial Broken Oxide Film m 0 7 x Micramoation a _ New Oxide Film Mew Oxide Film Micramoation After N Cycles Insulated GOLD TO TIN CONNECTIONS The connection of gold to tin is generally discouraged for the following reasons During the connection process there is a tendency for the tin to transfer to the gold The transferred tin eventually forms a tin oxide layer on the gold tin oxides very quickly at room temperature with normal levels of humidity The gold surface is actually harder than the tin and the oxide coating does not easily crack or rub off The oxide layer can build up fairly GENERAL MOTORS CORPORATION EDSON 2008 34 35 quickly if fretting is present resulting an increase resistance at the connection point GM s own internal experience has shown that tin to gold always results in problems and should be banned Per Andreasson However it has been documented in the book Electrical Contacts by Paul G Slade Editor that if the joint is lubricated prior to assembly the problem is minimized because the lubrication reduces the rubbing off of tin and protects the surface from the effects of moisture corrosion However the effectiveness of the lubricant only has a defined life span THE COMMANDMENTS GUIDELINES FOR THE USE OF TIN ON CONNECTOR CONTACTS The following is published by
279. load current for 15 minutes 4 Increase the current in increments of 1 ampere by changing the variable resistor value Apply the increased current for a 15 minute dwell period This is shown as phase one in figure 13 5 Continue increasing the current until the protection device fuse circuit breaker opens or any internal fusible link features in the DUT produce an open circuit GENERAL MOTORS CORPORATION EDSON 2008 6 Identify when time at what amperage level failure occurs Pay special attention for the generation of smoke or thermal activity near the time of failure 7 If an internal failure occurs before the external fuse opens then explore finer levels of current change between the current level of no failure and internal failure Use a 5 step exploration process within this one amp interval This is shown as phase two in figure 13 shown below 8 If the external fuse opens record the current value at the time of opening 9 Repeat Steps 1 8 at Criteria Functional Status shall be class E At no time during the test shall the device exhibit any indication of a thermal incident or generation of smoke The generation of some odor is acceptable Graceful death of the device is acceptable Figure 28 Load Circuit Over Current Test Procedure For Modules Load Circuit Over Current Test Procedure Example 10 amp fuse as the protection system with a rated load sdwy
280. ly devices that have connections to ground Procedure Monitoring Continuous monitoring is required to detect overheating and proper return to function Operating Type The test shall be performed under operating type 3 2 Use the test methods in accordance with ISO 16750 2 Single Line Interruption with the following deviations GENERAL MOTORS CORPORATION EDSON 2008 1 Disconnect all Ground lines simultaneously intended to provide ground to the module logic 2 Extend the duration of the interruption to 1 hour for each of power modes listed in the next step Disconnect the battery line s while in Off power mode with microprocessor asleep Off power mode with microprocessor awake Accessory power mode and the Run power mode 4 Each of the above tests shall be conducted with the outputs initially inactive and repeated with the outputs initially active 5 All I O is connected to actual or simulated loads 6 Monitor all output drivers with infrared cameras Or thermocouples 7 Conduct this test at Vmax 8 Conduct this test at Tmax except with agreement of GM Validation Engineer Criteria Functional status shall be at a minimum class C During the test temperature of the driver shall not exceed its maximum storage temperature GROUND OFFSET The Ground Offset Test is required when the DUT has two or more grounding connections This test simulates the condition where differe
281. ly intended to produce the highest possible humidity level without generating extreme condensation or rain Revision of GMW3172 2008 will require an increased temperature and test duration for the constant humidity test The HHCO test temperature will increase from 65 to 85 or to Tmax if less than 85 The test duration for the HHCO test will increase from 7 days to 10 days The reasons for increased temperature and duration are the result of recent field issues of electro migration between layers in the PCB of a cluster Special Concern For Fuses Within The Bussed Electrical Center The zinc material used inside fuses becomes maximally reactive with high humidity and a temperature of 85 C The Cyclic Humidity Test when applied to Bussed Electrical Centers can be conducted as described above however fuse integrity should receive special attention Purpose Evaluate the functionality of DUTs during exposure to extreme humidity and temperature GENERAL MOTORS CORPORATION EDSON 2008 252 295 Locations of Applicability This test is applicable to all areas of the vehicle Procedure Monitoring Permanent parasitic current monitoring is needed for every DUT over the 10 day test period to detect malfunctions during the test Operating Type The test shall be performed under operating type 2 1 during the test The DUT shall be evaluated using operating type 3 2 at the end of the
282. m the total acceleration factor used in testing Increased strain resulting from extended thermal range applied in test Coffin Manson Equation AT 2 5 Coffin Manson Acceleration Factor E field A dwell period at the end of each change of temperature allows the continuation of creep to occur within the solder until the stresses resulting from the temperature change have dissipated The effect of testing with less dwell time than would occur in the hands of the customer must be comprehended in the calculations Longer dwell times will result in more damage per cycle However damage accumulation is not linear with time There is a diminishing level of damage accumulation with time and the optimum dwell time needed for maximum damage per unit of time for leaded solder is approximately 4 minutes Empirical testing has shown that the acceleration factor resulting from a decreased dwell period is Dwell Time Acceleration Factor 768x min utes T The rate of change of temperature does not have a very large effect however unlike lead free solder a faster ramp rate represents test acceleration at the molecular level Ramp Rate Acceleration Factor 80094x Ramp Rate Mi The highest temperature reached during thermal cycling can have a significant effect on damage accumulation Given equal thermal cycling ranges the range with the highest temperature will generate the most damage This effect with leaded solder is less pronounced tha
283. mid Heat Constant HHCO All products must pass this test to prevent long term ingress of water vapor into components This test also checks for dendritic growth type problems Moisture Susceptibility a This test is required of all products to ensure adequate robustness against the formation of condensation on circuit boards Corrosion Tests Salt Mist or Salt Spray M mS This test is intended to accomplish the following The product should be washed clean following this test to evaluate appearance and loss of material Corrode pathways into the case that may allow moisture or salt water to reach the circuit Corrode exposed connector leads to the point that there is high risk loss of parent material Enclosure Tests 155 Dust The Dust Test may degrade convective cooling ability of temperature producing devices on the circuit board or may create wear when mechanical motion is involved Dust may also contaminate unsealed relays Water GENERAL MOTORS CORPORATION EDSON 2008 Bd Program located on the vehicle Interior devices should be tested with a water drip or splash type test to simulate condensation or things being cleaned spilt in the vehicle Seal Evaluation This test is required by an 8 code in the water portion of the International Protection Code The Seal Evaluation test is intended to evaluate the seal quality of devices that may be located within 20 inc
284. monitoring or you really need to know if the product will work properly while the stress of the test is being applied Operating types 1 pertain to no voltage being applied at all Operating types 2 pertain to when the generator is not active but voltage could be coming from the battery Operating types 3 pertain when the vehicle is running and everything is connected and working Operating Type Electrical State i No voltage is applied to the DUT 1 1 Not connected to a wiring harness Connected to a wiring harness simulating vehicle installation but no voltage applied The DUT is electrically connected with supply voltage Us battery voltage generator not active as in a vehicle with all electrical connections made System or component functions are not activated e g sleep mode Systems or components with electric operation and control in typical operating mode 1 2 DUT is electrically operated with supply voltage Ua engine alternator operative with all electrical connections made System or component functions are not activated Systems or components with electric operation and control in typical operating mode GENERAL MOTORS CORPORATION EDSON 2008 FUNCTIONAL STATUS CLASSIFICATION CODES The Functional Status Classification describes how the device is allowed to behave during the test and after the test You and the supplier must understand what FSC code applies to each test Th
285. mp Volts Para Eval Initial Temp Volts Para Eval Optional 40 G Mech Shock Closure Slam Test Vibration With Thermal Temp Volts Para Eval Initial Temp Volts Para 25 G Mech Thermal Salt Shocks Shock Corrosion Optional 40 G Mech Shock Closure Cyclic Or Constant Humidity Detection Vibration with Thermal Post Temp Volts Para Eval Initial Temp Volts Para Eval THIET rM GENERAL MOTORS CORPORATION EDSON 2008 Cyclic Or Constant Humidit Initial Volts Para Eval 25 G Mech Thermal Salt I Shocks Shock Corrosion 40 Code Testing Dust IP Code Testing Water Post Temp Volts Para Eval Initial Temp Volts Para Eval IP Code Testing Dust loo Test Leg Test Test 2 2 Leg 3 Leg 4 Initial Temp Volts bilit Initial Temp Volts Para Eval Moisture Suscepti bilit Para Eval Para Eval Moisture Suscepti Humidity Fretting Corrosion ISO 8820 Over Current Room Temp Unom Volts Para Eval fa Fretting ISO 8820 Over Current 136 Vibration With Thermal Initial Initial Temp Temp Volts Volts Para Para Initial Temp Volts Para Eval 500 100 6 25 Thermal Salt 20 High Mech Shocks Shock Corrosion To Temp Shock 40 bilit Optional 40 G Mech Shock Closure Slam Test Vibration With Thermal Volts Volts Para Para
286. mperature storage test which is of little value Changing the test to include the ability of the product to wakeup has improved the value of the low temperature test This test is required of all products and is shown in the long horizontal bar at the beginning of the test flow Purpose This test verifies DUT functionality after prolonged exposure to low temperature extremes Locations of Applicability All locations Procedure Monitoring The DUT is only monitored during the wakeup portion of the test Operating Type The test shall be performed under operating type 2 1 while the DUT is cold soaked operating type is 3 2 during times of evaluation as shown in the diagram below GENERAL MOTORS CORPORATION EDSON 2008 Testing shall be performed according to IEC 60068 2 1 Test Ab Tmin of the operating temperature range is the low temperature that is to be used At the start of a 24 h cycle the test parts Shall be energized at room temperature for 2 minutes and evaluated for proper function at Unom The DUT shall then experience a cold soak condition for 24 hours at operating mode 2 1 At the end of 24 hours and while still in the cold environment the product is to be turned on or awakened from its sleep state and evaluated for proper function for 1 hour at operating mode 3 2 Figure 39 Low Temperature Wakeup Test Profile TRoom Temperature Tmin Time gt Mode 3 2 Operating
287. mperature used during testing can have significant effect on the amount of creep that occurs during the thermal transition Creep occurs much faster at higher temperatures In this example we will use a 95 high temperature during thermal shock to accelerate the test and we are not worried about functioning at this temperature because we do not energize the device during thermal shock 1 1 4 Highest Temperature Acceleration Factor tS 275 1414 1 Highest Temperature Acceleration Factor a 1 113 gt Step 6 Leaded Solder Total Multiplication of Acceleration Factors AT AT 2 5 1414 1 _ 1 Total Acceleration Factor 4 4 768 x dwell minutes 80094 i Acceleration Factor 17 46 842 1 04 1 113 17 02 Number of Cycles 321 68 17 02 gt Thermal Shock Step 7 Leaded Solder Accounting For The Reduced Sample Size We must now increase this value by 1 124 to compensate for the fact that we are only using 18 parts instead of 23 parts see appendix B for calculations Final Number of Thermal Shock Cycles 321 68 1 124 361 57 Cycles gt PTC Step 8 Leaded Solder Applying The Coffin Manson Equation To The Remaining 25 PTC Cycling Damage Now we need to address the remaining 25 of the damage and this will be accomplished using Power Temperature Cycling PTC which permits c
288. my fault Alex Porter For want of a nail a shoe was lost For want of a shoe a horse was lost For want of a horse a rider was lost For want of a rider a message was lost For want of a message a battle was lost For want of a battle a kingdom was lost All for want of a nail George Herbert 1593 1632 The smallest things can make all the difference 125 GENERAL MOTORS CORPORATION EDSON 2008 Figure 11 Process Flow For Electrical Component Validation pue UBISeq 109 Ad Jo maney AC Wo Jo Uoqenjeag Jalyddns pawwouad Ad time m usg 199 uonepiie A ubIsac IO ubIsec Agee B2 SALA 7 Jayddns Aq uonepi e A uBisec S52 554 6 4 5154 ubisec 106 seu o ejreudojeec JO Mel amp e ubisec AUIGEIS uonenjeag 58 Tuatudo sAerc IEDISAUA 6 AQ GNI d ubisac 104 BI IO Malay UBISag Ul pm eddig Aq senno je n jeug SU odes 6 N 55 Z LEAN 104 MOIO IAA yyh jeauiBu UONEPIEA 54561 LEMAS
289. n Code letter Code letter Code letter Code letter Code letter Code letter Per Table 2 Per Table Table4 Per Table5 Per Table 6 Per Table 7 Engine Compartment High location A F remote from 7 C F A E 6 engine heat sources Typically C High location A F H A IP6K9K heat sources At in engine A F normal 7 6 temperature pane Typically C At in engine A F high E A or B Z E IP6K9K temperature oa Typically C At in Low mounted Engine IP6K6K toward the A mounted Ror port and IP6K8 engine compartment else SE 6 lower temp CorG and IP6K8 Low mounted Engine IP6K6K near the rear mounted and IP6K8 of the engine or B H Typically IP6K9K temp G IP6K8 97 GENERAL MOTORS CORPORATION EDSON 2008 Mounting Electrical Mechanical Temperature Climatic Chemical Dust and Location Loads Loads Loads Loads Loads Water Protection Code letter Code letter Code letter Code letter Code letter Code letter Per Table 2 Per Table Table 4 Table 5 Per Table 6 Per Table 7 Passenger Compartment Low A F temperature _ load Under Typically IP5K2 dashboard Normal temperature A F load E C E A IP5K2 Dashboard display or Typically switch High temperature A F load Top of dashboard Ty
290. n after thermal cycling 222200000 Zone Refining Refining Sn Ag Bi Fillet Lift Last area to cool Pb rich First areas to cool More Concerns With Bismuth Pb Contamination Concerns Mixing Bismuth Why Bi alloys are not the short term solution Onset Temp deg C 250 0 225 E 3 Pb 6 Pb T 150 A 100 5 Sn Bi Pb 75 eritectic Sn Bi Pb Eutectic n 8Ag n 2Ag 2Bi Sn 2Ag 4Bi Sn 2Ag 75Bi Sn 105Bi Sn 12Bi 07Cu ELE LT 10 00 Cumulative Pere EM 5 00 BI 45501 2 3 8599 12 34 35 5 2 289 5 7 5604 1 Bismuth Without Lead iw With Lead Weibull We 3RX MED F 24 5 _ V Ah zu rs Eg SnAgcuBisnzu W2 3RX SRM MED S 1900 00 Cycles 10617556 9722 z 082 2 162 0 96842 3 1910106 p D 98 Key solder Alloy omaonent Finish 4 42 1244 0 929 TG oo pat n The Above Graphics From Dr Ronald C Lasky and Timothy Jensen Indium Corp Loss of Thermal Fatigue Life with Bismuth Lead Mixtures GENERAL MOTORS CORPORATION EDSON 2008 5 3 4404 8 C 5 3 4 94 8 0 78 D umm Failures Thermal Cycles 40 to 125 C The Above Data And Graphics From Tom Woodrow The Effects Of Trace Amounts Of Lead On The Reliability Of Six Lead Free Solders
291. n temperatures are to be monitored during the test Operating Type The operating type shall be 3 2 Perform the evaluation the procedure in GMW8288 per Criteria Modify the design if necessary per the guidelines in GMW8288 FSC A HUMIDITY TESTS IN DEVELOPMENT MOISTURE SUSEPTABILITY The new moisture susceptibility test replaces the previous dew test and frost test The new moisture susceptibility test repeatedly produces condensation on the circuit board twice a day over a 10 day test period This test shall be used for all modules whether sealed or not Products such as radios may have difficulty passing this test For example the tuner circuit board portion of the radio cannot be conformal coated as that will reduce tuner performance The uncoated tuner circuit board becomes sensitive to moisture condensation Therefore with products like radios this test is to be run and the time to failure in days noted for each product tested The validation engineer will have engineering discretion in determining acceptability for the GENERAL MOTORS CORPORATION EDSON 2008 190 191 specific application This determination of acceptability will be based upon the number of days of testing during which the product was able to continue to work acceptably Purpose This test evaluates the products robustness against electro migration dendritic growth resilience against high impedance
292. n as possible following graphic shows the general learning curve shape and how our methods can alter the steepness of the slope of the learning curve Fast Learning Cycles Are Necessary In Each Phase To Achieve Product Maturity Through Many Learning Cycles d d Demand For Reliability is Greater Today Today 7 Necessary Maturity of Product rd o Lo eeee Reliability H Maturity Deficit H Learning Curve Product P From Traditional Maturity 2 Methods 4 Ge Production Now Starts Time N Production Used To Start Here Here The learning opportunities can be partitioned into three major groups Analysis Development and Validation Our objective is to use these opportunities cumulatively We cannot afford to only use one opportunity such as only V Trading one opportunity for another would also not benefit our cumulative learning desire as we need every opportunity to develop product maturity Therefore we are not working a strategy to replace V activities with A activities but rather to build a series of opportunity to develop product maturity The following graphic portrays the development process with each of the major screens A D V detecting and removing design errors in the product development stream 81 GENERAL MOTORS CORPORATION EDSON 2008 Using Every Opportunity Possible Build Product Maturity Prior to Market Introduction Product develo
293. n gaps to prevent electrical connection Plated through holes experience stress during thermal excursions in manufacturing and from thermal cycling in the field When heated the circuit board expands significantly more 7 direction than in the X or Y direction This 7 axis expansion imposes significant tensile stress the plated copper barrel This phenomenon is aggravated with the use of lead free solder as higher temperatures will occur during manufacturing Poor design or poor quality constructions will result in cracking failures of the barrel during ESS testing or soon after the product is placed into service The following two graphics show a cross section of a plated through hole and a barrel cracking failure in a plated through hole Figure 6 Cracks In the Walls of The Plated Through Hole GENERAL MOTORS CORPORATION EDSON 2008 60 61 INTERCONNECT STRESS TEST IST TESTING IST is the testing of coupons during circuit board manufacturing to ensure that interconnects such as VIAs have adequate strength VIAs are often known as plated through holes This screening test is composed of gt Several preconditioning thermal cycles from ambient to the peak temperature experienced during manufacturing reflow or wave soldering to replicate assembly and rework This is followed by thermal cycling to failure or to a pre defined number of thermal cycles gt Thermal cycle testing to
294. n intermetallic bond between the pin of the component and the VIA hole The increase in temperature is accomplished using an IR reflow process PIN IN PASTE CONSTRUCTION PROCESS squeegee Board with hole Stencil Solder paste Component assembled Reflow soldered The Above Graphic From Dr Ronald C Lasky and Timothy Jensen Indium Corp Figure 1 Pin In Paste Construction SOLDERING Soldering is the process of forming intermetallic bonds between dissimilar metals in order to form a mechanical and an electrical bond This is accomplished through the use of heat In contrast welding is the actual melting of both metals to form a connection Soldering is not welding Welding is an inherently stronger joint forming process GENERAL MOTORS CORPORATION EDSON 2008 56 a7 CHIP ON BOARD CONSTRUCTION The silicon die is directly attached to the circuit board without first being encapsulated in a plastic housing The silicon die is covered over with a glob of non conducting epoxy as a protective cover This construction allows for high density packaging without the use of solder Thermal Fatigue Can Also Affect Chip On Board Construction Sup Well Epoxy Multilayer Substrate Accelerated thermal cycle testing would use an exponent of 5 1 if you were only concerned about the breaking of gold bond wires Generally we use the lowest numerical exponent value bas
295. n it is with lead free solder The acceleration factor that reflects this effect is as follows 1 5 4 Highest Temperature Acceleration Factor 278 Trestmax 279 These acceleration factors are multiplied together in the following equation to be used as a devisor to reduce the number of thermal cycles defined by the Service Life The total acceleration factor equation appears as follows GENERAL MOTORS CORPORATION EDSON 2008 290 291 Equation 5 Leaded Solder Acceleration Factor 2 5 1414 Total Acceleration Factor saded soider x 768x dwell minutes 80094 field Service Life Defined The life of the E E device has been defined as 7 300 thermal cycles with a service temperature change of Delta T 43 for passenger compartment Delta T 69 C for underhood environments Delta T 98 C for on engine applications The 7300 cycles for one life is derived from cumulative damage modeling considering that each cycle may be of a different duration For simplicity sake the 7300 thermal cycles may also be expressed as two cold starts per day for ten years 2 X 365 X 10 The customer usage as described above allows for 45 minute dwell periods hot and cold and this should be considered the worst case Testing with shorter dwell periods will accumulate only a portion of the damage that would have been created
296. n of the product in the vehicle The code for this product 15 product reliability of at least 97 with statistical confidence of 50 shall be demonstrated on as described within GMW3172 The supplier must attain world class reliability for this product The test requirements contained this document are necessary but may not be sufficient in all cases to meet this world class field reliability requirement The supplier is responsible for assuring that other actions are taken such that world class field reliability requirements are met The requirement code for this product must be clearly assigned in the CTS or SSTS Supplemental testing for failure mechanisms not covered by GMW3172 must be specified in addition to GMW3172 These additional failure mechanisms may include wear or mechanical fatigue Figure 10 Code Letter Sequence Requirement GMW3172 Code Letter Sequence p 9 5 4 5th IP6K6K Electrical Code Table 2 H Mechanical FH Code Table 3 tz Temperature Code Table 4 Climate Code Table 5 Chemical Code Table 6 Dust and Water International D B I P6K6 K Protection Code Table 7 Example Only GENERAL MOTORS CORPORATION EDSON 2008 122 123 Target Life It is important to understand that the Target Life defines a quantity of damage for each failure mechanism such that the damage is
297. n result in momentary shorts he dendrites will vaporize themselves in the shorting out process and the circuit board will perform Denarites satisfactorily after the fact Inspection of a circuit board _ Burnt Dendrite Residue following this process will reveal small black burnt 5 traces that looks like pencil lines between traces Moisture voltage exposed copper closely spaced traces and ionic contamination are the key players LEAD FREE SOLDER Lead Free solder is a composition that contains less than 1 lead by weight The most common alloys of lead free solder are composed of Tin Silver Copper Sn Ag Cu SAC The best performance cost composition is SAC305 3 silver 0 5 copper with the remainder being tin The primary weaknesses of SAC type lead free solder as compared to leaded solder are gt Approximately 30 C higher temperatures of surface mounted components during reflow assembly operations gt Slower wetting of soldering surfaces during the solder assembly process gt Double the cost for the raw material and the need for all new processing equipment gt Environmental concerns with silver Ag GENERAL MOTORS CORPORATION EDSON 2008 gt Lead free solder is stiffer and stronger than leaded solder but is less ductile This results in lead free sometimes being more reliable than leaded solder and sometimes less reliable than leaded solder This is shown in the followin
298. nd hold this decreased voltage for at least 5 seconds Check the reset behavior of the DUT Repeat the test pulse with a hold time of 50 ms at each decreased voltage and check the reset behavior of the DUT Note the dwell periods between the voltage drops may be as long as Functional status should at minimum class C BATTERY VOLTAGE DROPOUT The Battery Voltage Dropout Test is simulating the condition of battery depletion from lights or some other load being left on while the engine is not operating This test is not intended to replicate the cranking of engine during the starting process Purpose Determine if the E E device is immune to decreases and increase in battery voltage This condition may occur when lights are left on which results in rundown of the battery or when the battery voltage increases during times of battery charging Locations of Applicability All devices in any location that may be effected by a gradual drop or increase in voltage Procedure Monitoring Continuous monitoring is required to detect intermittent faults Operating Type The test shall be performed under operating type 3 2 for zones 1 E2 and E3 needed for adequate product evaluation Criteria GENERAL MOTORS CORPORATION EDSON 2008 test shall be performed under operating type 2 1 for zones T1 T2 T3 1 Set up the battery voltage dropout profile as shown in figure
299. nd recyclable In thermoset plastics adjacent polymer chains form strong cross links When heated these cross links prevent the polymer chains from slipping past one another As such thermosets cannot be reflowed once they are cured i e once the cross links form Instead thermosets can suffer chemical degradation denaturing if reheated excessively VIBRATION WITH THERMAL CYCLING The following vibration tests reference different test conditions for cars and for trucks This document will define a truck as a vehicle that will be used in a commercial or semi commercial environment A pickup truck would be considered a truck while an SUV or crossover vehicle would be considered a car Vibration Tests have superimposed thermal cycling during the vibration test A device that is normally attached through a bracket should be tested without the bracket in place The DUT shall be directly attached to the shaker table through an adequately rigid fixture The bracket is to be evaluated per the Bracket Random Vibration test using the random vibration profile appropriate for the attachment location GENERAL MOTORS CORPORATION EDSON 2008 Load support TH Table Flexure M EU i 4 Coil on Form Inner Pole Piece Outer Pole Piece Body Compliant Isolation Mounts Figure 29 Cross Section of an Electro Dynam
300. nector is oriented 5 downward from the horizontal when the car is parked ona flat surface that is horizontal to earth 15 downward is considered a best practice o Now we park this car on the steep road 14 2 in San Francisco such that the connector is now facing 14 2 minus 5 9 29 in an upward direction o Water that may condense and fall on this device will now be landing on the device with the connector facing upward 9 2 from the horizon o The IP lab test should test the device with the connector oriented upward at a 9 2 angle Code 3 Luggage areas that may see more water from snow or sports should consider using 3 level test Code 6K The 6K test is intended for exterior applications where a car wash may apply water at 125 psi Consider using the 6K requirement for non sealed systems that include non sealed relays Code 8 The Seal Evaluation Test code 8 Devices that are located underneath the vehicle should receive the seal evaluation test even if they employ a Gortex patch The test will be used to ensure that all of the seals perform satisfactorily This requirement should not be used to GENERAL MOTORS CORPORATION EDSON 2008 112 113 drive cost but rather to provide knowledge as to what may happen in severe usage situations Devices located high up underneath the vehicle should be required to pass the 6K test and the Seal Evaluation Test Devices that are required to pass the Seal Evaluation Te
301. ng demonstrated The two moisture tests following thermal fatigue testing are qualitative in nature and follow thermal fatigue testing so that cracks in seals that may have developed in thermal cycling are made available for the penetration of water vapor with a is only a The 1 hour vibration thermal cycle test detection process and is not intended to create additional damage This 1 hour vibration with thermal change test is designed to detect intermittent failures that may have been created during thermal fatigue or humidity testing This detection test be shortened by starting with the DUTs in a pre cooled state Tmin and only applying vibration during a single thermal ramp to Tmax Good dissection at the end of this test leg is essential in identifying the onset buds of possible problems Sectioning of some solder joints may be necessary during this dissection process Test Leg 4 CORROSION DUST AND WATER PROTECTION This is primarily the corrosion test followed by dust and water testing Environmental Protection Tests dust and water follow the corrosion test because corrosion could have caused a water leakage path that would be detected with the IP water Test Test Leg 5 WATER CONDENSATION This is the moisture susceptibility test leg Unlike humidity that is intended to diffuse water vapor into plastic encapsulated micro circuits the moisture susceptibility test 15 intended to produce th
302. ng table is a good starting point for determining your test code sequence Begin by identifying the area of the car you re product will be located Review each suggested letter and make adjustments in the letter suggested if necessary Remember the Z code is always available for special circumstances where you wish to define unique values for some of the specifications Use the Z code with caution and experience More than one set of codes can be used to cover multiple vehicle applications when necessary Current Air Flow Dynamics 129 C Ignition 149 C Alternator Surface Surface 7 424 n b 7 148 Transmission 148 C Engine Block 129 C o WS 5 Exhaust System 587 C Road Surface 66 C Shown In Celsius With An Outside Temperature Of 40 C 105 F On A Sunny Day GENERAL MOTORS CORPORATION EDSON 2008 96 This document distinguishes between the following mounting locations defines the minimum Electrical Mechanical Thermal Climatic Chemical Water and Dust Protection requirements Other mounting locations are possible and can be addressed using a custom combination of code letters as described in the section entitled Quoting Requirements Table 1 Code Letters Based on Location in the Vehicle Mounting Electrical Mechanical Temperature Climatic Chemical Dust and Location Loads Loads Loads Loads Loads Water Protectio
303. nically with sun load Low A F mount under IP5K2 seat Typically C IP5K8 Other Locations A F CorD A C F IP5K8 Typically A F CorD A C 5 2 Typically Doors and A F hatches wet IP5K3 area Typically C Doors and A F hatches dry E D A IP5K3 area Typically C A F Exterior A F Chassis and IP6K8 or Un sprung A F Jor N 6 mass Typically C IP6K6K GENERAL MOTORS CORPORATION EDSON 2008 98 Mounting Electrical Mechanical Temperature Climatic Chemical Dust and Location Loads Loads Loads Loads Loads Water Protection Code letter Code letter Code letter Code letter Code letter Code letter Per Table 2 Per Table 3 Table 4 Per Table 5 Per Table 6 Per Table 7 Sealed body cavities nly oe 7 C H I F IP5K4K body cavities the base of IP6K6K the windshield A F Also run inside the I E Scar Plenum or Typically Evaluation inside the if in engine plenum compartment Roof mounted A F C IP6K2 or inside the IP5K2 vehicle cabin Typically GMW3172 Code Letter Sequence st 2 50 4th 5th IP6K6K Electrical Code Table 2 Mechanical Code Table 3 Temperature Code Table 4 Climate Code Table 5 Chemical Code Table 6 Dust and Water CCCDB P6K6 K m d International Protection Code Example
304. nitoring for proper function occurs during post evaluation GENERAL MOTORS CORPORATION EDSON 2008 Operating operating type shall be 1 2 during the test and operating type 3 2 during the post test evaluation e Pour or splash 200 milliliters of Sugar water into the DUT and wipe away standing or surface liquid e The device shall be mounted in its intended orientation with bezels and covers in place e sugar water liquid shall be poured into horizontal devices from the vertical direction and splashed into vertical devices from a horizontal direction e Sugar water is defined as 200 milliliters of water with 10 grams of sugar fully dissolved e Sugar water is to be applied from a distance of 30 centimeters e The DUT shall remain un disturbed and allowed to dry at room temperature for 24 hours prior to the evaluation of function Criteria Functional status shall be Degradation in operational forces and audible quality of function sticking and gritty controls shall be compared to the specification DESIGN VALIDATION RESULTS REVIEW A validation results review should be performed the results of the validation tasks with the intent of identifying what tasks may need to be repeated for PV Purpose Identify weaknesses or lack of design margin and initiate corrective action now A refocusing of attention during PV should occur based upon weaknesse
305. nitoring is required throughout the test to detect intermittent failures Operating Type The test shall be performed under operating type 3 2 Use test methods according ISO 16750 3 Test I Passenger car engine During vibration load testing the DUT shall be simultaneously subjected to vibration and temperature cycles according to the vibration test temperature cycle The DUT shall be electrically operated and continuously monitored while test Sinusoidal followed by random vibration tests are to be performed on the same DUT Combined sine on random testing may be performed in one test run if there is a desire to reduce the time on test The specified test profiles apply to both gasoline and diesel engines The test duration for both the sinusoidal and random vibration test is 22 hours each axis for a sample size of 23 parts The test duration shall be adjusted using the Appendix for Success Run Statistics when smaller sample size is used The suggested smaller sample size is six as shown in the test flow GENERAL MOTORS CORPORATION EDSON 2008 sweep For lt 5 cylinder 240 200 20 4 440 150 15 3 1 engines Shaft M cultus 270 100 10 2 engines 4 Envelope 2 cylinder engines 440 100 10 2 pp with a balance Random Engine Vibration Sinusoidal Engine Vibration Figure 32 Random Vibration Profile Figure 31 Sinusoidal Vibration For For Engine Mou
306. noticeable in lead free solder Internally developed compressive stresses from the cooling process or the diffusion of copper into tin can cause tin whiskers to form as compressive stresses are reduced This phenomenon will occur without any special environmental condition being imposed Parts on the shelf at room temperature will develop tin whisker formation almost as quickly as parts in service Components that are soldered lead free to the circuit board should have a boundary layer an example would be nickel plating between the copper and the tin The boundary layer will significantly reduce tin whisker formation by reducing the diffusion of copper into tin A second tin based phenomenon known as Tin Pest is also possible when the tin is not protected Wart like formations on the tin will begin to appear in cold temperatures and will degrade the tin into a gray powder GENERAL MOTORS CORPORATION EDSON 2008 280 281 The tin pest phenomenon is cold temperature driven starting at 139C and reaches a maximum reaction rate at 30 C The phenomenon can be eliminated as long as there are minute traces of lead in the tin Four nine s tin extremely pure should not be pursued as this will be more susceptible to Tin Pest No acceleration factor for thermal shock is to be applied to Lead free solder Thermal shock does continue to be a desirable method for obtaining more thermal cycles per unit of time and will co
307. ns where failure could occur Sample size is 18 gt Thermal Shock Step 1 Lead Free Partitioning One Field Service Life Damage Into The Thermal Shock Damage Target and The PTC Damage Target We wish to generate 75 of the total damage using thermal shock in the interest of faster and less expensive testing 7300X 75 5475 Thermal Cycles gt Thermal Shock Step 2 Lead Free Applying The Coffin Manson Equation To The 75 Damage To Reduce The Number Of Thermal Cycles With Increased Thermal Range Testing We wish to generate an equivalent degree of damage using fewer cycles but will offset the fewer cycles with greater strain using expanded thermal range testing The specification is 409 to 85 C delta T of 125 C however in thermal shock we are generating thermal fatigue damage with the device un powered and can use an expanded temperature range We can extend the low temperature down to the Homologous Temperature point and we can increase the high temperature provided we do not exceed material limits The product in this example can withstand 40 C to 95 C Delta T is 135 C and we will use this beyond specification thermal test range to decrease the number of thermal cycles required on test The Coffin Manson Equation gives us the equivalent damage relationship GENERAL MOTORS CORPORATION EDSON 2008 284 m Coffin Manson Acceleration Factor 27 field Note m 2 65 for lead free solder Solder represents
308. nt portions of the vehicle may have different ground potentials This could result from poor grounds or from different length ground wires Purpose This test shall determine if the device functions properly when subjected to ground offsets between platform modules Locations of Applicability location but only devices that have more than one ground wire attached to the device Procedure Monitoring Continuous monitoring is required to detect intermittent faults Operating Type test shall be performed under operating type 3 2 he offset shall be applied to each ground line separately and simultaneously The voltage values shown apply to all interfaces of a module supplied with Unom GENERAL MOTORS CORPORATION EDSON 2008 206 Ground offset between platform modules 1 Apply to the DUT 2 Subject ground line to a 0 8 V offset relative to the DUT ground 3 Perform a Functional Parametric Test under these conditions 4 Repeat for next ground line 5 Repeat for lines simultaneously 6 Repeat for a 0 8 V offset relative to the DUT ground 7 Repeat 2 through 6 at Umax Ground Offset Test Setup At U min Wall S Ground 2 0 Volts Negative Ground Ground 1 8 Volts Negative DUT Swap Ground 1 And Ground 2 To Produce Opposite Voltage Effect Ground Offset Test Setup At U max Wall Ou
309. nted Devices Engine or Transmission Engine Mounted Random Vibration Profile Sinusoidal Vibration for Engine or Transmission 100 5 cylinders envelope 2 5 cylinders envelope 1 N lt 10 C E 0 1 1 10 100 1000 10000 100 1000 Frequency Hz Frequency Hz Acceleration m s 2 Pi RMS Acceleration Value Note A worst case profile will use the highest level from either 181 m s rms 18 4 Grms line Table 23 Random Vibration Profile Engine Mounted Table 22 Engine Transmission Sinusoidal Vibration Severity Frequency Acceleration Power Power Spectral Envelope 1 Envelope 2 Density Density Maximum Freq Maximum Hz Acceleration Hz Acceleration m s Hz g Hz m s Gs m s Gs 100 10 2 100 10 2 GENERAL MOTORS CORPORATION EDSON 2008 226 227 Criteria Functional Status shall be class A throughout the test No objectionable squeaks rattles Should be present before or after the vibration test Random Vibration Mounting Location Sprung Masses Purpose This test evaluates the DUT for adequate design margin for fatigue resulting from random vibration induced by rough roads
310. ntinue to be used per this specification Lead free solder requires a longer hot and cold dwell than does leaded solder for creep to occur While this has little bearing on field usage it has a significant effect when lab based accelerated thermal cycling is used to evaluate fatigue life Lead free solder requires three times the dwell duration as does leaded solder to achieve optimum damage per unit of test time Research has shown that a 10 minute dwell period is optimum for lead free solder The calculations shown in Appendix E provide an example for designing the thermal cycle testing for an interior module MS HE oth Ro p didi GIUnaAnn fap AER M PHILAPS SEMMCoeDO 1 3 dum BN Ui jor M Du m2 A if Har Els SAGA Dee 4S at AUTOMATION n GENERAL MOTORS CORPORATION EDSON 2008 Appendix Lead Free Solder Guidelines for Thermal Shock Testing and Power Temperature Cycle Testing gt Understanding The Source Of Total Damage During Thermal Cycling In The Lab For Lead Free Solder The damage developed during thermal cycling is the product of four components The acceleration factors from these four components are multiplied together to form the total acceleration factor used in
311. nute D well 80 One PTC Thermal Cycle For Lead Free Solder Ramp Rate Shown Is 7 Degrees C min Note The circuit board temperature is shown as a dotted red line The 60 chamber dwell periods must be 40 extended to insure that adequate dwell occurs on the product Extra Dwell Required Due To Thermal Inertia Temperature C 20 Shown With 79C Per 40 Minute Occurring on the Circuit Board 60 Time Minutes For One Thermal Cycle 70 This Is The Only Time When The Product Is Off And No Power Moding Is Occurring GENERAL MOTORS CORPORATION EDSON 2008 Table 29 Power Temperature Cycling Requirements Range Operating type Temperature transition rate Dwell time Minimum 2 to 15 1 C min with the understanding and approval of GM Engineering A single product must be thermocoupled as pre test assessment to determine the thermal lag time resulting from thermal mass A 10 minute hot dwell and 10 minute cold dwell is to be used once the product is within 3 of the target temperature The Dwell Timer shall begin when the product reaches Tmax minus and Tmin plus 3 The damage generated with Power Temperature Cycling Should represent at minimum 25 of the total damage by thermal cycling The minimum number of cycles shall be 100 An appropriate number of cycles to reach the required reliability should be taken from the st
312. o 85 per this specification and generates an additional 10 degrees from self heat then the thermal shock test should be run from 40 to 95 Figure 41 Thermal Shock Test Profile 10 Minute Dwell One Thermal Shock Cycle Shown With 19 C Per Minute Occurring on Note The dotted red line is the temperature on the product Extra dwell time is needed to compensate for product thermal inertia to insure that the product receives the required duration of dwell as specified the Circuit Board Extra Dwell 10 Minute Dwell Required For Thermal Inertia Temperature Celsius Time Minutes For One Thermal Cycle GENERAL MOTORS CORPORATION Figure 42 Air To Air Thermal Shock Chamber EDSON 2008 Figure 43 Parts Inside Air Air Thermal Shock Chamber 4 B M r CELL dy Tet 4 L nr ws i Criteria Functional status shall be class A after this test POWER TEMPERATURE CYCLE PTC B The Power Temperature Cycle Test is the second half of the thermal fatigue test duo This test produces the remaining 2575 of the total thermal fatigue damage following thermal shock Most importantly this test is the detection step in thermal fatigue testing Constant monitoring is a requirement during testing Many of the problems in Validation are detected
313. o I tell you I rather guess She was a wonder and nothing less Colts grew horses beards turned gray Deacon and deaconess dropped away Children and grandchildren where were they But there stood the stout old one hoss shay As fresh as on Lisbon earthquake day EIGHTEEN HUNDRED it came and found The Deacon s masterpiece strong and sound Eighteen hindred increased by ten Hahnsum kerridge they called it then Eighteen hundred and twenty came Running as usual much the same Thirty and forty at last arive And then come fifty and FIFTY FIVE Little of all we value here W akes on the morn of its hundredth year W ithout both feeling and looking queer In fact there s nothing that keeps its youth So far as I know but a tree and truth This is a moral that runs at large Take it You re welcome No extra charge FIRST OF NOVEMBER the Earthquake day There are traces of age in the one hoss shay A general flavor of mild decay But nothing local as one may say There couldn t be for the Deacon s art Had made it so like in every part That there wasn t a chance for one to start For the wheels were just as strong as the thills And the floor was just as strong as the sills And the panels just as strong as the floor And the whippletree neither less or more And the back crossbar as strong as the fore And the spring and axle and hub encore And yet as a whole it is past a doubt
314. o Chrome Eta 5 F 8 S 0 IPL Weib 80 Degrees C With Chrome Eta 1 00E 6 Life 10000 00 5 F 8 S 0 1000 00 100 00 10 00 100 00 Stress 1 00 What Weibull Slopess hot S N Slopes Beta1 4 0220 K1X4 1416Ef10 n1 3 4942 Beta2 1 9168 K241 0207EX9 n2 4 3703 Beta3 9 7019 K N CRITERIA FOR FATIGUE AND STRENGTH PER GMW14048 Crack Parent Metal Durability Critical Functional Area Occurrence of a parent metal crack that is longer than twice the metal thickness or longer than 5mm whichever is less Non Critical Functional Area Occurrence of a parent metal crack longer than 10mm that rapidly propagates or that propagates through the entire test duration Strength The occurrence of a parent metal crack detected by unaided visual inspection Crack Weld Separation Durability Critical Functional Area Occurrence of a crack in a weld greater than 5mm Non Critical Functional Area Occurrence of a crack in a weld greater than 20mm or 209 of the specified weld length whichever is less 27 GENERAL MOTORS CORPORATION EDSON 2008 Strength The occurrence of a crack detectable by unaided visual inspection Note that stress relief cracks are to be documented when rapid propagation or propa
315. o is responsible GMW3172 The chairman of the GMW3172 team is Larry Edson that s me I have chosen to write this handbook as a personal initiative to help those who wish to better understand the depth and background of this specification GMW3172 Team is composed of the following individuals Hans Peter Andrae GME Germany Per Andreasson GME Sweden Markus Armbrust GMNA ISP Silvestre Avila GM Mexico Larry Edson GMNA Greg Fleck GM Powertrain Tom Higgins GME ISP Yibo Hu PATAC Edward Jamieson GM Holden Tony Kruszewski GMNA Then he almost fell flat on his face on the floor When picked up the chalk and drew one letter more A letter he never had dreamed of before And said You can stop if you want with the Z Because most people stop with the Z Ishkan Kurdian GME Sweden Chris Lucarelli GMNA Carlos Pascon GM Brazil Qayoum Rezazada GM Canada Bijay Rout GM India Heidi Schatton GME Germany Roland Schuh GME Germany Jennifer Senish GMNA Sungwoo Shim GMDAT Christian Dr Ziegler GME Germany But not me the places go there are things that see That never could spell if stopped with the Z telling you this cause you re one of my friends alphabet starts where your alphabet ends Dr Seuss On Beyond Zebra GENERAL MOTORS CORPORATION EDSON 2008 16 ABBREVIATIONS AND SYMBOLS A D V Analysis Development
316. obotic system is used to pick up the assembly and drag it over a single point select wave or dip the assembly into multiple nozzles that are mounted on a product specific nozzle plate In contrast the soldering process utilizing traditional wave soldering equipment consists of transporting the entire assembly by means of a conveyor system over a liquid solder wave PLATED THROUGH HOLE CAPTURE PADS PLANE CLEARANCE HOLE PLANE LAYER INSULATION GAP HOLE PLATING COPPER FOIL HOLE SHADOW ANNULAR RING Figure 4 Graphics of The Cross Section of A Plated Through Hole or VIA The plated through hole or VIA is a method of interconnecting the different traces in a multilayer circuit board Capture Pads are place on the outer most layers to capture the plated through hole and connect the surface traces to the plated through hole barrel Holes are drilled through the capture pads and through the laminate circuit board material usually FR 4 Chemical treatment of the hole allows uniform adherence of the copper material during the subsequent electro plating operation Clean cut holes and proper electro plating chemistry are necessary to ensure a uniform wall GENERAL MOTORS CORPORATION EDSON 2008 of plated material plated wall connects to intersected traces inside the sandwich that are exposed during the drilling operation Plane layer traces that are not to connect to the barrel are designed with insulatio
317. om fatigue with road vibration Purpose The analysis of plastic snap lock features is performed to ensure the following e Adequate retention force e Acceptable ergonomic forces for assembly e Designed in compliance mechanisms to prevent rattles e Adequate design margin to ensure that flexing during installation does not exceed the elastic limit of the plastic Locations of Applicability Applicable to all locations in the vehicle that incorporate such features GENERAL MOTORS CORPORATION EDSON 2008 162 163 Procedure Complete the Plastic Snapfit Design Worksheet in Appendix M Additional resources to assist in completing this worksheet are Design of Integral Attachments and Snapfit Features in Plastic Alternatively finite element analysis maybe used Criteria Use the criteria as noted in the Plastic Snapfit Design Worksheet in Appendix M to insure that the elastic limits of the plastic material are not exceeded BRACKET FATIGUE ANALYSIS The analytical process described in Appendix O will assist the engineer in designing a bracket that will have adequate fatigue life for 10 to 15 years of use in the vehicle example shown in Appendix assumes that the device is mounted on the body or chassis thus using the sprung mass vibration test as the source of stress If the bracket is to be mounted on the engine or on an un sprung mass then the appropriate vibrat
318. on constraints or geometry interferences an over designed minimum quantity snapfit system should be used The all snapfit approach should be the last resort in the design strategy 2 Ultimately two different design forces will surface that must be specifically addressed in the design process These two forces must be defined and understood before the design process can proceed e The force that works to disconnect the attachment e The force needed by a human being to assemble the attachment a The snapfit will most probably be required to retain a dynamically functioning force This is certainly true in automotive applications Vibration usage forces and the accidental drop must be comprehended by the retention requirement First calculate the actual weight that the snapfit must hold and then calculate the effective weight that must be retained resulting from the dynamic effect of impact operating on that weight Example e Retention force required under dynamic conditions Our attachment must retain 1 Ib weight e 10 Gs are expected to operate on the 1 Ib weight as a result of extreme pothole encounters 305 GENERAL MOTORS CORPORATION EDSON 2008 e retention force should be at least 10 times the weight of the part being retained greater than 10 155 retention force 15 required e My retention force requirement is Ibs b Snapfits are generally designed to utilize a human assembly process
319. on damage accumulation Given equal thermal cycling ranges the range with the highest temperature will generate the most damage The acceleration factor that reflects this effect is as follows 1 1 ze Highest Temperature Acceleration Factor Mhetamax 278 Testmax 273 These acceleration factors are multiplied together in the following equation to be used as a devisor to reduce the number of thermal cycles defined by the Service Life The total acceleration factor equation appears as follows GENERAL MOTORS CORPORATION EDSON 2008 282 Equation 4 Lead Free Acceleration Factor _ Dwell time Y Total Acceleration Factor 26 2 15 x 1 22x ramprate x ome ET 273 field Dwell gt Service Life Defined The life of the E E device has been defined as 7300 thermal cycles with a service temperature change of Delta T 43 C for passenger compartment 45 minute dwells Delta T 69 C for underhood environments 45 minute dwells Delta T 98 C for on engine applications 45 minute dwells The 7300 cycles for one life is derived from cumulative damage modeling considering that each cycle may be of a different duration For simplicity sake the 7300 thermal cycles may also be expressed as two cold starts per day for ten years 2 X 365 X 10 The customer usage as described above allows for 45 minute dwell periods hot and cold and this should be
320. on is not expected during shorting Monitor for overheating and for return of proper function at end of test Operating Type test shall be performed under operating type 3 2 loads on 1 Raise and stabilize the chamber temperature to Tmax 2 Apply Umax to the DUT 3 At t 05 power mode the DUT from Off to On The outputs under test shall be activated no later than t 5 s 4 At t 15 s apply all of the short circuit conditions described during a 5 minute period and then remove all short circuits for 2 minutes and 45 seconds the combination of steps 3 and 4 should equal 8 minutes 5 Power mode the DUT from On to Off 6 Repeat 3 through 5 until 60 cycles are complete total short circuit time equals 8 hours After completing the 60 cycles perform any required recycle reset cool down conditions and confirm the correct operation of the outputs with normal loads 7 Adjust the battery voltage to Umin and repeat steps 3 through 7 8 Stabilize the chamber temperature to Tmin and repeat steps 2 through 7 Note If multiple shorts are applied simultaneously then the supplier shall make sure that the test is valid for Single shorts as well Criteria Functional Status shall be class C The Short circuit fault shall not prevent any other interface from meeting its GENERAL MOTORS CORPORATION EDSON 2008 176 177 requirements The DUT shall pass all Functional Parametric
321. on test duration should not receive any additional adjustment for variation in mileage requirements as may be called out in the VTS if that value is within the 100 000 to 250 000 mile range RELIABILITY Reliability Please review the section on Stress Strength Non Interference at the front of this document to better understand why we require 97 reliability test 50 GENERAL MOTORS CORPORATION EDSON 2008 confidence as related to the specified reliability is used based upon GM policy and ease of conversion between test to failure and success run methods The R 97 has been reverse engineered from a field reliability requirement of R 99 5 The reverse engineering process used a Customer Variability Ratio of three and a Weibull Slope of two when actual data was not available The 99 5 field reliability has been benchmarked as world class from Toyota Honda vehicles which demonstrated electronic device reliability values of 99 A product reliability of at least 97 with a statistical confidence of 50 Shall be demonstrated for the failure mechanisms of vibration fatigue the vibration portion of vibration with thermal thermal fatigue thermal shock combined with PTC fretting corrosion humidity with temperature change and vibration BEC s only relative to the target life The test plan for reliability demonstration must encompass the important Interactions between fatigue
322. onstant monitoring Thermal shock does not permit monitoring or product activation as the parts are transported back and forth between two different chambers The PTC test keeps the parts stationary with the single thermal chamber producing a slower rate of temperature change on the part than does thermal shock The 25 portion of the damage is as follows 7300 5475 1825 PTC Cycles GENERAL MOTORS CORPORATION EDSON 2008 294 We will use the Coffin Manson Acceleration Factor Equation to reduce the number of thermal cycles while increasing the strain with increased thermal cycling range The PTC test generates damage but is also most critical in detecting problems The product must be operated and monitored at all times during the PTC test We will use the specification level temperature requirements of 40 C to 85 C Delta T 125 C for this test because the product will be functioning and constantly monitored during the test PTC Step 9 Leaded Solder Applying The Coffin Manson Equation To The 25 PTC Cycle Damage To Reduce The Number Of Thermal Cycles With Increased Thermal Range Testing We wish to generate an equivalent degree of damage using fewer cycles but will offset the fewer cycles with greater strain using expanded thermal range testing The specification is 409 to 85 C delta T of 125 C Coffin Manson Equation gives us the equivalent damage relationship AT Coffin Manson Acceleration Factor e fiel
323. ontrol or command information is delivered via a data link Procedure 1 r each test case in the test plan set up the appropriate functional operating conditions and for each I O related to the function sequentially apply 4 Short to ground condition 2 short to supply or battery voltage 3 An open circuit condition Apply each fault injected state long enough to identify any functional effects and or to verify the correct activation of relevant fault identification recovery and diagnostic GENERAL MOTORS CORPORATION EDSON 2008 315 algorithms Document the observation and the acceptability judgment on the test script matrix When inputs are in the form of digital values the fault injection format shall be 1 Outside of valid data range Low Value 2 Outside of valid data range High Value 3 Data absent or withheld Apply each fault injected state long enough to identify any functional effects and or to verify the correct activation of relevant fault identification recovery and diagnostic algorithms 2 Move sequentially I O by I O data link value by data link value and function by function through the detailed test plan until all test conditions are completed Acceptance Criteria 1 It is acceptable for the injection of a disruptive condition to discrete I O circuits to falsely trigger or prevent activation of its related function 2 It is not acceptable for a fault injection on an analog circuit to
324. ood adhesion to the base metal The following graphic shows wetting force with soldering occurring at 262 C higher than normal amr Solderability f Pb free Solderability SAC 305 300 300 200 7 SAC NNNM SAC 3X HJ 0 ce Requirement Zero Cross Time 1s mE 200 0 0 5 1 1 5 2 2 5 3 3 5 4 4 5 5 0 0 5 1 1 5 2 2 5 3 3 5 4 4 5 5 Time sec B Time sec 200 2 nPb 0x SnPb 3x 400 SnPb ox Force uN mm Force uN mm GENERAL MOTORS CORPORATION EDSON 2008 The following graph compares the time needed to reach 66 of the maximum wetting force for leaded and lead free solder Notice how the lead free solder must operate at the upper reaches of the curve in order to stay away from the destructive potential to components when temperatures rise above 260 C Lead Free LOT e d o i o c _ ad gt a C o Test gem C SEMICONDUCTOR COMPONENT CONSTRUCTION The following diagram shows the internal construction of a typical semiconductor component Shown are the costs for the various elements in this type of device Molding Compound Nitto Denko Silicon Die 8 cents gt Wire Bonded Tanaka 18 cents Die Attach Adhesive Ablestik cents Leacdframe Shinka J cents 94 cents per lead GENERAL MOTORS CORPORATION EDSON 2008 52 53 CRACKED CERAMIC CHIP CAPACI
325. or is oriented 5 downward from the horizontal when the car is parked on a flat surface that is horizontal to earth Now we park this car on the steep road 14 29 in Francisco such that the connector is now facing 14 2 minus 5 9 2 in an upward direction Water that may condense and fall on this device will now be landing on the device with the connector facing upward 9 2 from the horizon The IP lab test should test the device with the connector oriented upward at 9 2 angle Codes other than 2 shall have the device mounted in the in car position and this orientation to the horizon shall be maintained as the DUT is placed upon the horizontal Support plate for test Example An underhood product that is mounted at a 45 degree angle in the car and is required to pass the 9K test will have portions of its underside sprayed as the spray nozzle travels down to the horizontal spray position GENERAL MOTORS CORPORATION EDSON 2008 260 Test as specified by IEC 60529 Table VIII Water Test Water Duration Code Means Flow Rate of Test 261 Use DIN 40050 Part 9 for IP code 9K Alternately 15020653 combines the requirements of the and DIN specifications For IP Codes 4K and the following additions to Table VIII apply As in item 3 IEC 60529 except with an opening diameter of 0 8 mm at 90 spray 10 min 5 min in one position 5 min turned 909
326. or re disperse silver particles with a loss of conductivity Electrical pathways Failure Mechanisms With ACF And Chip On Glass Thermal Thermal Cycling ME SSS se good electrical 31 good electrical good bond Gaz good bond 25 Silver Particles In Contac Adhesive With Silver Particles z Good Bond after lt lt poor electrical poor electrical 4 good bond Adhesive With Fractured Bond fracture at high TCE surface Heat and Humidity s Notes These types of Diffusion Of Oxygen failures are possible Ex the latest improvements AFTER AGING Adhesive Results In have done much to Oxidation Of Metal address all of the above Contact Surface Cookson Electronics GENERAL MOTORS CORPORATION EDSON 2008 54 55 CHIP ON GLASS CONSTRUCTION Chip on glass construction involves the direct bonding of the silicon die to the electrical conduction pads on the back of the glass This construction method is most often used with LCD backplane glass and uses either Anisotropic Conductive Film ACF or something similar to form the bond and electrical connection This construction is affected by the same stresses that are destructive to ACF bonding Chip On Glass Attachment Explanation Not A Failure Mechanism Two Designs Shown Anisotropic Conductive Film ACF
327. ornelius D nald D ll could A few brand new wonderful words he And think perhaps maybe did him might spell some good led him around and tried hard to Show Dr Seuss On Beyond Zebra There are things beyond Z that most S11 GENERAL MOTORS CORPORATION EDSON 2008 Appendix Hardware Software Functional Robustness Testing Processor Supervisor Performance Evaluation Purpose This procedure is intended to verify that that the system supervisor circuit was correctly implemented and is effective in recognizing faults and initiating corrective action attempts Digital micro processing devices use a Dead Man Like Switch supervision circuit known as a Watchdog or COP Computer Operating Properly to monitor for the continued presence of a State of Health SOH indicator signal To ensure that disruptions and faults can be rapidly detected and corrected the supervisor circuit monitors special pulses sent by the microprocessor Programmed pulses are sent by the microprocessor within specified time intervals as the result of hand shaking typically between timing interrupt routines and the main programming loop If the supervisor is not toggled within the pre defined time period it is assumed that the processor is hung up or executing an endless loop The supervisor then generates a pulse to the processor to warn that a fault has occurred typically this directly or indirectly triggers a system reset The reset proc
328. osed with Sinusoidal alternating voltage This simulates the output of a poorly damped alternator over a full range of engine RPMS Locations of Applicability All devices in any location that may be effected by an extreme level of A C ripple on the 12 volt wiring system GENERAL MOTORS CORPORATION EDSON 2008 Procedure Monitoring Continuous monitoring is required to detect intermittent faults Operating Type The test shall be performed under operating type 3 2 Use the test methods in accordance with ISO 16750 2 Superimposed alternating voltage Severity Level 2 4Vp p Criteria The functional status shall be class A Pulse Superimposed Voltage Test Within Normal Levels Purpose Verify the performance of the E E device when the supply voltage is superimposed with a voltage pulse within the normal operating voltage range This voltage pulses will mimic a sudden high current load change to the battery supply line causing a voltage drop or voltage rise at switch on or switch off The pulse profiles used simulate loads with inrush current behavior like e Motors e Incandescent bulbs e Long wire harness resistive voltage drops modulated by PWM controlled high loads This test is also an important tool to test diagnostic behavior for open load detection and short circuit protection of high side drivers feeding intelligent GENERAL MOTORS CORPORATION EDSON 2008 loads slave units or PW
329. ot have failed before the requirement at normal stress then the copper wire should be temporarily ruggedized to allow the test to continue beyond the previous copper failure to determine if the solder joint will meet its requirement Effect Of S N Slope On Accelerated Testing The Slope Of This Line Is The m Value In The Acceleration Factor Equation _ 4 eL NN Soy The Copper Wire And The Solder Joint Are Equally Log Durable At Normal Stress DES Of MM SS Life The Copper Wire Fails e a Before The Solder Joint At Elevated Stress w ta ta 4 Elevated Stress Normal Stress Log Of Stress S DEMONSTRATING RELIABILITY FOR THERMAL FATIGUE ROBUSTNESS The following graph and table for thermal fatigue testing provides the lifetime damage equivalent of the vehicle in terms of thermal cycles and change in temperature The baseline damage values for example delta T 43 degrees with 7300 thermal cycles are used as the starting point to develop the accelerated test that produces equal damage in less time The Modified Norris Landzberg Equation provides the relationship GENERAL MOTORS CORPORATION EDSON 2008 to correlate an accelerated thermal fatigue test to the baseline requirement Explanations and sample calculations for developing the accelerated test from this baseline is provided in Appendix E and The
330. ot occur if the testing was conducted using only PTC testing with its slower thermal ramp rate Seal Evaluation Test This is a very severe test to evaluate hermetically sealed enclosures including potted devices The DUT is heated to Tmax and then submerged three inches under ice cold salt water This process will tend to ingest water resulting from the negative change in pressure This process is carried out 15 times ina row on the same DUT This test is required for all sealed and unsealed Goretex patch devices that are gt Located within 20 inches of the ground on the exterior of the vehicle gt Products that are located in basin areas within the vehicle such as under the front seat or in the spare tire well gt All potted products Salt Test This is the corrosion test Products inside the vehicle should receive the salt mist test less than 10 days and products outside the vehicle should receive the salt spray test 10 to 40 days Cyclic Humidity and Constant Humidity These tests are required for all products including those that are sealed Moisture Susceptibility Test This test is required for all products GENERAL MOTORS CORPORATION EDSON 2008 Xenon Arc Testing This test or an outdoor equivalent is required for those products that will be exposed to the sun The details of this test are to be defined by the materials department The 7 is always available when you must compose a combination o
331. oted below Equation 11 Arrhenius Peck Acceleration Factor For Temperature and Humidity a Acceleration factor Humidity ign Where Boltsmann s Constant 1 380 658 0 000 012 x 10 J K or 8 6173 X 10 7 eV K 1 E Average Conservative Activation Energy 1 28 x 10171 0 8 eV T2 T1 Lower Temperature ambient Higher Temperature on test Temperature is in Degrees Kelvin Celsius plus 273 and humidity is in 9o RH GENERAL MOTORS CORPORATION EDSON 2008 302 303 Appendix L Relationship of Reliability On Test To Reliability In The Field And Design Margins Test To Field Correlation The tests included in this specification are based on a severe user The reliability that is required 97 is based on these severe user tests The expected reliability of the product in the hands of the normal array of users is greater than what is demonstrated on test Benchmarking activities where used to identify the level of reliability that was required in the field 995 and the reliability on test 97 was derived from that benchmarking effort The following table provides an example of the test to field correlation for electronic products The reliability of the device can be demonstrated analytically for the failure mechanisms of vibration and or thermally induced fatigue Special note Weaknesses that were not anticipated during analysis may exist in the product and
332. ounted Module Lead Free Table 11 Test Test Le Test Leg Test Test Test Test Leg 2 2 Leg 3 Leg 4 Leg 5 Leg 7 Sn Initial Initial Initial Initial 1 Temp Temp Temp Temp Volts Para Volts Volts Volts Para Volts Eval Para Eval Para Eval Para Eval Eval Para Eval 100 G 20 Moisture Mech 2 i To Suscepti ae Humidity 1 Shock g 40 bilit 25 G Mech PTC Fretting Shocks Corrosion Optional 40 G Mech Cyclic Or IP Code bi im Shock Constant Testing Current Closure Humidity Dust Slam Test Vibration Detection With Vibration Thermal with Cycling Thermal IP Code Testing Water Post Post Post Temp Temp Temp Volts Para Volts Volts Eval Para Eval Para Eval Volts Para Eval Test Leg 4 Test m Test Leg Test Leg O 2 2 Leg 3 Initial Initial Initial Initial 1 Volts Para Volts Volts Volts Eval Para Eval Para Eval Para Eval Eval Para Eval 100 G 20 Moisture Mech 422 4 22 To Suscepti ae Humidity 1 Shock g 40 bilit 25 G Mech PTC Fretting Shocks Corrosion Optional 40 G Mech Cyclic Or IP Code Shock 1 Constant Testing Current Closure Humidity Dust Test Slam Test Vibration Detection IP Code With Vibration Testing Thermal with Water GENERAL MOTORS CORPORATION EDSON 2008 140 Eval Temp Volts Para Initial Initial Temp Temp Volts Para Volts Eval Para Eval
333. ours to 10 33 hours while the stress level Grms remains the same Now one can reduce the test time back to 8 hours or even less if we choose with a necessary increase in energy level Grms The following example sprung mass for a car vibration profile uses the Accelerated Vibration Testing Equation to allow a reduction in test time through an increase in vibration energy level Equation 7 Accelerated Vibration Stress Life Equation Tes Tim normal G Test Time normal accelerated GENERAL MOTORS CORPORATION EDSON 2008 298 Where Gnormal The normal loading Car example 2 84 Grms Gaccelerated accelerated test loading m Material Fatigue Constant 6 4 for aluminum leads in electronic assemblies 5 for an overall usage value 4 for connector fatigue or fretting Corrosion problems and 3 3 for highly accelerated vibration for metal fatigue greater than 3X original stress The supplier is responsible for documenting the source of the material fatigue factor used for the device under test xm Test Time Normal Test Time Accelerated 10 Grms 2 84 6 4 ee ae accelerated 8 The results of this car example show the following Grms rms G accelerated normal e 23 parts need from Success Run Equation e 12 parts will be used with a resulting increase in test time from 8 hours to 10 33 hours e Test time reduced back to 8 hours with a resulting increase in Grms on test
334. ow the math that predicts that the strain the plastic will be less than the maximum permissible strain This strain generally occurs during the time of maximum deflection during assembly e Show the math that dictates the ramp angles for engagement and disengagement of the snapfit feature Detail the profile of the ramps on the snapfits e Show the math that dictates the dimensions and all proportions of the flexed snapfit feature Engineering is always a compromise Write down what you believe are the two most prominent weaknesses of this snapfit attachment design even though you have rigorously engineered this assembly This information will assist the design team in understanding what key dimensions or handling packaging considerations should receive special attention during manufacturing Guides Should Be Employed To Act As Alignment Tools Outside Of The Snapfit Process guide system should provide the effect of fitting a shaft into a large cone Guides should provide full control of motion prior to the engagement of any snapfits Guides are often used in a cumulative manner as explained in the following Good Example e Good Example The first guide is easily seen by the operator and positions the engagement process in one axis A second guide is engaged following the first and begins to control rotation No remaining attention must be given to alignment and the operator has only to concentrate on insuring complete
335. pansion and contraction rates of circuit board elements result in fatigue stress to the junctions involved solder and lead wires differential expansion rates of different materials may also GENERAL MOTORS CORPORATION EDSON 2008 166 16 result in the unacceptable deformation of structure resulting in electrical or mechanical problems Locations of Applicability Applicable to all locations the vehicle Procedure Identify the most at risk elements of the product as follows e Identify the largest surface mounted component the circuit board e Identify components whose Coefficient of Thermal Expansion CTE differs the most from each other Perform the analysis to quantify fatigue life and expansion contraction differences that will result in problems This cyclical stress fatigue can be modeled with the empirical models detailed in reference 1 Steinberg or through Finite Element Analysis Criteria The design margin shall be large enough to meet the reliability requirement Review Appendix L for a description of how much design margin is required to meet the reliability requirement ANALYTICAL RESULTS REVIEW An analytical results review should be performed on the results of the analytical tasks with the intent of identifying where there is a lack of design margin A refocusing of attention during development may be necessary as a result of this Analytica
336. parts instead of 23 parts see appendix B for calculations Final Number of PTC Cycles 128 9x1 124 144 9 Cycles The combined Thermal Shock plus Power Temperature Cycle testing should take approximately 2 5 weeks if the thermal chambers are used 24 hours per day Lead Free Summary The same set of 18 parts will receive 318 Thermal Shock Cycles and will also receive 145 Power Temperature Cycles The Validation Engineers Poem The Deacon s Masterpiece Or The Wonderful One Hoss Shay Oliver Wendell Homes Senior 1809 1894 Have you heard of the wonderful one hoss shay That was built in such a logical way It ran a hundred years to a day And then of a sudden it ah but stay tell you what happened without delay Scaring the parson into fits Frightening people out of their wits Have you ever heard of that I say Seventeen hundred and fifty five Georgius Secundus was then alive Snuffy old drone from the German hive That was the year when Lisbon town Saw the earth open and gulp her down And Braddock s army was done so brown Left without a scalp to its crown It was on that terrible Earthquake day That the Deacon finished the one hoss shay Now in building of shaises I tell you what There is always a weakest spot In hub tire felloe in spring or thill In pannel or crossbar or floor or sill In screw bolt throughbrace lurking still Find it somewhere you must and will
337. per Weibull analysis methodology An example of six parts tested until 4 failures have accumulated is shown below The four failures are plotted on Weibull paper and a life prediction is made The failure values are organized in ascending time value and their corresponding median rank value assigned In this example we will use the first 4 median ranks out of a total sample size of 6 We use these 4 out of 6 values because we had six parts on test during the time of accumulating the 4 failures The paired plotting points using the median rank values for a sample of 4 are as follows the earliest failure in your data 10 9 the second failure in your data 26 4 the third failure in your data 42 1 the fourth failure in your data 57 9 the fifth failure in your data 73 5 NOT USED the sixth failure in your data 89 1 NOT USED Ov ul BR WN F amp F GENERAL MOTORS CORPORATION EDSON 2008 276 product in this example meets the reliability requirement exactly because the best fit Weibull line passes through the intersection of 8 hours 8 hours each axis for a total of 24 hours and 97 reliability requirement 3 failure Any line passing to the left of this point will not meet the requirement and any line passing to the right of this point will more than meet the requirement The slope of this line will vary as a function of the variability of the test data Special Not
338. plate represents the sole of a person s shoe Apply this force to connector and DUT header as shown in the diagram below The DUT shall be designed to prevent imposing such load when the connector system is unable to sustain such foot loads Figure 19 Foot Load Method B Connector Test Foot Applied Force Normal Force Applied In The Middle Of The Steel Plate 50 mm X 50 mm Steel Plate Bridging The Gap Between and 0 Header J Connector 5 Vehicle Wo ere eee arte e ee Mating Connector Body DUT Case Fastened To Support Structure Support Structure Represents The Vehicle s Floor Pan or Bracket Criteria The connector header system shall be able to withstand the above mechanical stress without any shear or yield or loss of function or loss of electrical isolation Additionally there shall be no degradation of the circuit board resulting from any of the forces that may be transmitted by this test GENERAL MOTORS CORPORATION EDSON 2008 MECHANICAL SHOCK There three basic mechanical shock tests 1 The pothole test simulates the effect of hitting large potholes in the road while traveling at moderate rates of speed The pulse that is generated from hitting a pothole results in a large G pulse with a half sine Shape that occurs in all axes The suspension rebound and the side to side reactions are the
339. pment should act as a series of screening opportunities intended to filter out design errors overlooked weaknesses and move strength away from stress Are these screens adequately discriminating Are these screens occurring quick enough to make a difference Squeeze Out Time Speed of learning within each screen is essential to produce as many learning iterations as possible within each phase Therefore the two main strategy rules in GMW3172 are Product Maturity A D And What is learned Value of what is earned Maturity Value Time needed to learn Cost of learning These two rules dictate that inexpensive methods of learning occur as fast as possible at every possible opportunity A wise person once said The greater the number of efficient learning opportunities the greater the maturity value GMW3172 is partitioned into Analysis Activities Development Activities and Validation Activities and are listed in that order in the ADV Task Checklist Generally these tasks should be performed in ADV order during product development In a few situations analytical methods have been used to replace rather than supplement the validation tests GENERAL MOTORS CORPORATION EDSON 2008 82 83 ANALYTICAL TASKS Analytical Tasks Most companies are not used to being asked to perform the analytical tasks or sharing the results of analytical tasks with GM It is essential t
340. present the opportunity to learn early in the program and prevent product delays during validation testing ELECTRICAL ANALYSIS NOMINAL AND WORST CASE PERFORMANCE ANALYSIS The Nominal Performance is often expanded to include the variation in individual component tolerances the effect of temperature extremes on circuit performance Many companies have software to model this worst case point of view Companies will alter their designs and software to ensure that the product will perform properly with Analysis all of these expected variations occurring You should ask to see that this work has occurred and to know that potential problems will be prevented before Validation begins Purpose This analysis is performed to verify that the design of the circuit is capable of producing the required output response Locations of Applicability Applicable to all devices in the vehicle GENERAL MOTORS CORPORATION EDSON 2008 158 159 Procedure Use circuit analysis program to analyze circuit performance using nominal and component tolerance extremes along with expected extremes in temperature conditions Criteria Verify that the design of the circuit is capable of producing the required output response under all conditions Must meet the requirements according to SSTS or CTS GMW14082 SHORT OPEN CIRCUIT ANALYSIS Purpose Performed to analyze how a circuit or systems response
341. probability of popcorning with plastic encapsulated components Popcorning is the cracking or exploding of the plastic case of the component resulting from high pressures of superheated steam The superheated steam is the result of trapped water vapor within the plastic matrix becoming superheated from the higher temperature soldering process Special efforts may be necessary to control the humidity of the environment of stored components awaiting assembly Discussions with the Supply Chain of component manufacturers must be conducted early in the program to prevent temperature related problems e Thermal aging time at elevated temperature can lead to the formation of Kirkendall Voids at the interfaces of tin and copper The formation of a string of these voids can produce a perforated tear line that represents a Significant weakness relative to mechanical shock The Universal 279 GENERAL MOTORS CORPORATION EDSON 2008 Durability Test Flow places the 500 hour thermal aging test prior to the first mechanical shock test specifically to address this concern Lead free solder quickly shifts from a ductile material to a brittle material at a temperature of 30 C This phenomenon does not happen with leaded solder This can represent a significant risk in high mechanical shock areas like the door engine and locations on unsprung mass The mechanical shock tests should be run at Tmin when lead free solder is used in the most severe appl
342. pure tin whiskers and immersion silver is susceptible to the formation of silver sulfide dendrites There have been no reported instances of tin whiskers on SnCu HASL finished PCBs However it should be noted that the use of SnCu HASL as a board finish has been very limited Aside from whisker and dendrite growth other aspects of the surface finishes will affect selection including cost shelf life solderability manufacturability corrosion resistance and technical limitations with certain assembly processes component types and board designs You should know what your supplier is using why he she made that choice and what risks may result The Following Table From iNEMI Printed Circuit Boards PCB Finish Tin Whisker Test Requirements SnCu HASL Electroless Nl Immersion Au Electroplated NI Electroplated Au Immersion Ag Immersion Sn OSP e g Entek The Following Table From Dr Ronald C Lasky and Timothy Jensen Indium Corp Thickness 3 8 2 an Fine pitch Poor Excellent Excellent Excellent Excellent quality i Contact Not nete Som i Not Cost 1X 2X 1X 1X To HASL qox qox ow x Hazard to E GENERAL MOTORS CORPORATION EDSON 2008 THE ADV PLAN OVERVIEW MAJOR ELEMENTS THAT SHOULD BE INCLUDED IN THE PLAN The ADV plan is to be formulated by the supplier and is documented in the ADVP amp R form The ADV tas
343. quantity causing harmful effects if the enclosure is continuously immersed in water under conditions which shall be agreed between Supplier and car manufacturer Water which is directed against the enclosure from any direction shall not have any detrimental effect pressure steam jet cleaning Table 8 Summary of FSC and Operating Types Test Title hace _ Operating Phase Type Jump Start 3 1 and 3 2 Reverse Polarity 6 2 1 2 2 Over Voltage D C 3 1 and 3 2 Intermittent Short Circuit 32 _ Continuous Short Circuit D C 32 GENERAL MOTORS CORPORATION EDSON 2008 116 i Phase Type Ground Interconnect Short To Battery D C 3 2 0 Characterization Evaluation Door Trunk Hood Slam Thermocouple Method Thermal Performance Development Infrared Imaging Method D and V Parasitic Current Voltage Beyond Normal Levels Pulse Superimposed Voltage Within Normal Levels Open Circuit Signal Line Single Interruption Open Circuit Signal Line Multiple Interruption Ground Offset Power Offset Load Circuit Over Current Modules E e e Ie WIW UJ ZIN N Pje 1 2 3 1 1 2 3 2 1 2 or 3 1 NJ UJ GJ N NIN m GJ Od 2 1 3 2 NJ I lwo o UJ UJ UJ UJ N N N v lt lt lt lt lt lt lt lt lt 3193153 ajaj
344. r Rev 3 Feb Expanded PV testing explanation On or off during 2006 jump start Expanded vibration explanation Any orientation during salt mist testing Jump start 26 0 1V Added full explanation of shipping vibration engineering changes Rev 5 April Addition of the Validation Timeline Pin in paste 2006 construction explained iNEMI tables for lead free added North America corrosion map added 269 GENERAL MOTORS CORPORATION EDSON 2008 6 2006 Expanded the section on Failure Mechanisms added explanation for step 4 of Parasitic Current Test Added metal crack failure criteria and updated table 8 2006 Rev 8 June 2006 Rev 9 Aug 2006 Rev 10 Oct 2006 Rev 11 Nov 2006 Rev 12 Dec 2006 Rev 13 Jan 2007 Rev 14 Mar Unified vibration test requirements for the range of 2007 100 000 to 200 000 miles Corrections made for suggested codes low temperature nderhood area Added copper solder example in thermal fatigue area Added HALT graphic in HALT explanation Worst Case added to Nominal Evaluation in Analysis Section Compliant pin explanation provided Expanded explanation of tin pest Expanded explanations for lead free Clarification of testing for the soakback temperature and the Tmax testing from re paint Three cycles of Dew Test added as alternative to the Frost Test Frost Test added to list of development tests Missing continuous short circuit test added to
345. rack Growth Crack propagation period Final Fracture Appearance Of Fatigue Failures Crack Initiation Occurred In This Area Note The crack does not propagate at a constant rate Sy Initial crack site ee 896 574 cycles 45 740 1205 cycles 780 cycles May become polished smooth from rubbing Failure Last Lip Of Metal To Give Way Minute Rings Develop During Each Cycle Of Stress Number of cycles N 21 GENERAL MOTORS CORPORATION EDSON 2008 Special Forms Of Fatigue Surface Fatigue u Sparing Fatigue Fretting Development of micro cracks from high pressure micro motion machine tools Traditional S N Curves Showing Stress As A Function Of Life Stress psi x 103 Note Longer tail is toward 100 longer life Note The endurance limit that we see with steel and iron does not exist with aluminum and copper Stress psi 80 60 Ferrous alloys and titanium Fatigue limit 40 gt ox Nonferrous alloys Fatigue strength bts O O at N cycles OO Suspensions 20 10 106 10 N 10 107 Cycles to failure 10 105 106 10 10 Cycles to failure N GENERAL MOTORS CORPORATION EDSON 2008 22 Fatigue The Validation Engineers View Of The S N Curve Life As A Function Of Stress Life vs Stress 1 00E 8 1 00E 7 Infinite 1 00E 6
346. rating type 3 2 to ensure unwanted activation does not occur Operating Type The test shall be performed under operating type 1 2 However when the device is monitored during the test for unwanted activations then the operating type should be 3 1 Final evaluation at end of test will be performed under operating type 3 2 he tests are conducted according to IEC 60068 2 27 Ea GENERAL MOTORS CORPORATION EDSON 2008 188 Table 16 Quantity of Mechanical Shocks For Closures Number of shocks in the main direction Driver s Door 100 000 Passenger Door Hatch Lid aE nue Trunk Lid 30 000 Table 17 Slam Based Mechanical Shock Loads 40 X gn Nominal shock 6 ms duration Nominal shock Criteria Functional status shall be class A TEMPERATURE TESTS IN DEVELOPMENT THERMAL PERFORMANCE DEVELOPMENT Products that have historically had problems with heat should make extensive use of these two tests GMW8288 provides extra details on thermal performance development practices Thermocouple Method Purpose Devices that produce heat locally or in many areas should receive special attention to ensure that the components and materials embody adequate design margin relative to the time at elevated temperature produced by the device Temperature measurements with thermocoupling are used to locate and visualize the DUT hot spots A radio or amplifier is an example of such a d
347. rature Tests Low Temperature Wakeup 5 Performed at the beginning of all test legs along with a check at high temperature to make sure that all of the products work properly prior to durability testing High Temperature Durability Used as both a diffusion test and as a preconditioning prior to mechanical shock This test must be run on all products post heating temperature requirement and elevated re paint and storage temperature requirement are to occur within this test Thermal Shock Air To Air TS E Absolutely required with demonstration of a reliability number R 97 amp 50 This test along with the PTC test will require the greatest amount of test time when using lead free solder Plan early in order to meet program timing Power Temperature Cycle PTC Absolutely required with demonstration of a reliability number 97 amp 50 This test must follow the Thermal Shock Test because this test will detect problems that may have been generated during the Thermal Shock Test Do not separate PTC from TS or run them in reverse order Humidity Tests Humid Heat Cyclic HHC M All products must pass this test to prevent dendritic growth type problems as well as internal corrosion of components This test induces a breathing action of the water GENERAL MOTORS CORPORATION EDSON 2008 152 Procedure This Program vapor and has proven very effective over many years Hu
348. red to detect overheating and proper return to function Operating Type The test shall be performed under operating type 3 2 Use the test methods in accordance with ISO 16750 2 Single Line Interruption with the following deviations 1 Disconnect battery lines simultaneously intended to provide power to the module logic 2 Extend the duration of the interruption to 1 hour for each of power modes listed in the next step Disconnect the battery line s while in Off power mode with microprocessor asleep Off power mode with microprocessor awake Accessory power mode and the Run power mode 4 Each of the above tests shall be conducted with the outputs initially inactive and repeated with the outputs initially active 5 All I O is connected to actual or simulated loads 6 Monitor all output drivers with infrared cameras or with thermocouples 7 Conduct this test at Vmax 8 Conduct this test at Tmax except with agreement of GM Validation Engineer Criteria Functional status shall be at a minimum class C During the test temperature of the driver shall not exceed its maximum storage temperature Open Circuit Ground Line Interruption Purpose Determine if the device is able to suffer no damage due to incomplete contact conditions and to determine if the part functions properly immediately after the completion of the contacts Locations of Applicability All location but on
349. ree Select Starting Box Based Upon What 15 Different Between DV And Nothing Except An Increase In Production Volume Frost Test if not sealed Shipping Vibration Test Cyclic Humidity Seal Evaluation if sealed Soft Tools To Hard Tools And No Remaining DV Problems Frost Test if not sealed Shipping Vibration Test Cyclic Humidity Seal Evaluation if sealed Added Manufacturing Line To Accommodate The Volume And No Remaining DV Problems Frost Test if not sealed Shipping Vibration Test Cyclic Humidity Evaluation if sealed Verifying Correction Of Prior DV Problems All Testing Needed To Verify Corrections Frost Test if not sealed Shipping Vibration Test Humidity Evaluation if sealed Changes In Components And Circuit Board Testing Needed To Address Changes Frost Test if not sealed Shipping Vibration Test Cyclic Humidity Seal Evaluation if sealed Every truth passes through three stages before it is recognized In the first it is ridiculed In the second it is opposed In the third it is recognized as self evident Arthur Schopenhauer Nineteenth century German Philosopher 1788 1860 GENERAL MOTORS CORPORATION EDSON 2008 ANALYSIS ACTIVITIES These activities should occur prior to the availability of physical parts Analysis activities re
350. relationship between sample size and test duration This is a common technique especially when a series of stresses need to be applied to a system The series of stresses can be applied a multiple number of times using a smaller sample size GENERAL MOTORS CORPORATION EDSON 2008 How We Reduce The Number of Parts s By equating Bayes Theorem with Waloddi Weibull s RELIABILITY Distribution we obtain the at original large sample size N new revised lower sample size D Weibull slope parameter shape of how this stuff fails Or in easier form NOMOGRAPH OF RELIABILITY AND CONFIDENCE LEVELS 4 1 1 DEMONSTRATED BY TEST NOTE ONLY VALID WHEN TESTING TO DESIGN LIFE VS MANN 11 hy ul 11 Larson s Binomial Distribution Nomograph The Lipson Equality Weibayes Original life requirement X new longer life requirement resulting from smaller sample CONFIDENCE LEVEL How To Use Draw a line between the confidence you want and the reliability you want Find where your line crosses the 0 failure diagonal line Read the number of samples required along the diagonal edge of the graph This is the number of samples that are to be tested to your Design Life objective with no failures occurring during the test Find C 50 and R 90 Find C 72 and R 83 Find C 72 and R
351. reported to GM engineering The supplier may be required to perform further investigation to determine the degree or X type of degradation GM engineering will decide as to the necessity of corrective action ELECTRICAL TESTS IN DEVELOPMENT JUMP START The Jump Start Test simulates the condition of being jump started with two 12 volt batteries in series There are two documented situations when this may occur A tow truck is called to jump start a vehicle with a dead battery in the winter in a parking lot When a vehicle is found to have dead battery as it is being off loaded from ocean transport ship Devices may have been left in the on or off position during the time of the jump start Both and off states should be tested using the 26 volt jump start An evaluation of the robustness of the contacts of relays should be considered if relays may be called upon to operate during the 1 minute duration of the 26 volt jump start Robustness of the contacts against GENERAL MOTORS CORPORATION EDSON 2008 172 1 3 welding shut resulting from the higher voltage should be evaluated During the jump the battery and get the car started process there could be a sequence of things being turned on and off Consider a reasonable sequence of events or operating modes which should be applied during the test This sequence should be agreed upon by the engineering team Purpose
352. ress The resonant frequency of the bracket is 150 Hz but the resonant frequency of the bracket with the device attached is 85 Hz The Pin value is identified in the following graph Body or Chassis Mounted Random Vibration Profile 1 1000 Frequency Hz The dampening factor Q for this assembly is Q 2x JF 2 85 18 43 The vibration level is not constant but rather varies as described by a normal distribution The force level of Gout x Weight Force pounds will occur 68 3 of the time using a probability of plus and minus 1 sigma A higher level of vibration plus and minus two sigma will occur 27 1 of the time and an even higher level of vibration plus and minus three sigma will occur 4 33 of the time All three of these stress levels will be operating randomly during the vibration process We must calculate each of the force levels as they will be used in the next set of calculations First we need to calculate the G level of acceleration that the assembly will experience during resonance Gout 5 x02 85 18 43 7 01 GENERAL MOTORS CORPORATION EDSON 2008 318 The force acting the Center of Gravity during resonance given the PSD identified above is 68 3 Of The Time The Force Will Be 1 Sigma Force Weight x 7 01 2x 7 01 14 02 pounds plus
353. ria for acceptability Monitoring N A Operating Type Criteria State change transients shall not produce disruptive levels of disturbance to downstream devices FSC A GENERAL MOTORS CORPORATION EDSON 2008 PROCESSOR SUPERVISOR PERFORMANCE EVALUATION The following Processor Supervisor Performance Evaluation assesses the probability that the logic circuit does not prevent a gridlock in communications Robustness evaluations are intended to confirm that the device Does What It Is Supposed To Do and Does Not Do What It Is Not Supposed To Do An example of this problem may be when a product shuts down or locks up when confronted with minor abnormality or behaves in an unsafe or unstable manner These procedures are to be performed as development and validation activities Purpose This procedure is intended to verify that the systems supervisor circuit was correctly implemented and is effective at recognizing faults initiating corrective action Locations of Applicability Al system that include micro processor Procedure Monitoring To be monitored continuously during the test Operating Type Operating type is 3 2 See Appendix N Criteria Ensure that disruptions and faults can be rapidly detected and corrected without inconvenience to the customer FSC A FAULT INJECTION The following Fault Injection Testing assesses
354. ribes your product necessary change the letter to best fit your product based on tables 2 through 7 Proceed from letter to letter until all test categories have been reviewed Write down your final choice for the code sequence This code sequence must be identified in the SOR that is sent to the supplier Supplier GMW3172 e ve Quickstart Flowcha You and Supplier at Finish opecifying tests and looking at test data is not enough You must discuss the tests the test setups how the test was run what was observed when it was observed and you need to see touch and inspect a sample of the parts that were tested This hands on engineer to engineer discussion is essential in knowing and understanding how your product is really performing on test This activity is also known as and should be the focal point in the Reliability Design Reviews that are required by GMW3172 The cadence of the Reliability Design Reviews are identified in the ADV Process Flow Chart The code sequence establishes the major environmental parameters for many of the tests required by GMW3172 However additional tests may be necessary based upon the requirements in the CTS The total collection of tasks are required are to be identified on the ADVP amp R form Additionally a GMW3172 Test Template should be completed with the assistance of a member of the GMW3172 Expert Team Detailed definitions
355. ronmental robustness and fatigue life of the mechanical mechanism This is a requirement in addition to GMW3172 GMW3431 GMW3097 A suggested method of addressing the mechanical system fatigue life is by using the Calibrated Accelerated Life Test Method CALT defined in GMWS8758 This method is also applicable to degrading wear processes such as horn contact life and relay contact life WHY ADV There was a time in GM history when we had the luxury of 5 years to develop and bring a vehicle to market The demands of the market now require us to do in 18 months what we once did in 5 years This means that we must increase the efficiency of what we do to meet our market objectives The GENERAL MOTORS CORPORATION EDSON 2008 80 market also requires us to deliver much higher reliability now than was required in the past This all translates into more reliable in less time Our old methods needed to change dramatically in order to accommodate both timing and maturity level requirements Fortunately other companies have traveled down this path before us and the methods have been developed and proven by others Like good students we listen and learn and adopt the methods that work the best Don t feel guilty as others will be doing the same from us Developing a product is simply a case of life on a learning curve We seek out every opportunity to design reliability into the product giving ourselves as many opportunities to lear
356. round Offset is shown below 1 Apply to the DUT 2 Subject the applicable power line to a 1 0 V offset relative to the DUT power 3 Perform a Functional Parametric Test under these conditions 4 Repeat for next applicable line 5 Repeat for lines simultaneously 6 Repeat for a 1 0 V offset relative to the DUT power 7 Repeat 2 through 6 at Umax Power Offset Test Setup At U min Wall Outlet Ground Negative Ground DUT Swap The Two B Lines To Produce The Opposite Voltage Effect Power Offset Test Setup At U max Sa Wall Outlet Ground Negative Ground Swap The Two B Lines To Produce The Opposite Voltage Effect Criteria The functional status shall be class A LOAD CIRCUIT OVER CURRENT MODULES The Load Circuit Over Current Test for modules simulates a condition where the protection fuse does not immediately open when the specified current is exceeded The product must not GENERAL MOTORS CORPORATION EDSON 2008 208 209 create a thermal or smoke hazard to the vehicle occupants The following is a revised version of the previous years procedure and is very similar to the Short Circuit Test described GMW3431 During this test one is hoping that the DUT will continue to function to the point that the upstream fuse opens or the DUT fails gracefully in an over
357. rrosion problems with these materials have been improved through the use of nickel Gold flashed polymer spheres and clorine free adhesives Pressure during application creates particle to particle conduction in the Z axis while the absence of pressure in the X and Y axis allows the particles to remain separated and not generate shorts between adjacent pads ACF construction is affected by thermal cycling stress on adhesive bonding and cyclic application of humidity and drying Humidity and oxygen will diffuse into the adhesive and cause oxidation on the surfaces of the particles and the conduction pads Re hydration following a drying period may result the loss of conduction as the metal particles are separated from each other during expansion of the epoxy matrix GENERAL MOTORS CORPORATION EDSON 2008 Anisotropic Conductive Film ACF Explanation Not A Failure Mechanism General Rule Pad size and spacing should provide a gap between the pads that is about 4 times the diameter of the particles Particle diameter is 2 3 um Pad gap is 8 12 um a Weaknesses are Cookson Electronics Adhesive is a poor barrier to oxygen thus oxidation of particles and KEY INTERFACES 1 Particle to component 2 Particle to particle 3 Particle to circuit polymer binder metal surfaces can occur Thermal cycling can amp fracture adhesive bonds surfactant
358. s remaining from DV and any changes necessary between DV and PV Procedure Perform the Appendix B design review per Criteria Initiate corrective action as early as possible in the product development cycle GENERAL MOTORS CORPORATION EDSON 2008 264 PRODUCT VALIDATION ACTIVITIES 265 The move to lead free Product Validation tries to detect major weaknesses that develop as a result of changes occurring between DV and PV Weaknesses can result from changes in location of manufacturing major process changes or product design changes The type of engineering change and the degree of change will dictate what testing is necessary Product Validation is not intended to statistically quantify the degree of variation occurring in production The supplier and General Motors shall jointly determine exactly what testing is necessary for process validation and what sources of variation shall be included in the testing Changes in location of manufacturing major process changes or product design changes should dictate what kind and amount of testing is necessary for product validation Additionally weaknesses in the design margins of the product as seen during Design Validation should be considered in developing the Product Validation plan The supplier and General Motors shall jointly determine exactly what testing is necessary for Process Validation Evaluation Of Solder Repaired Products The move to
359. s test process is applicable to cars and trucks where the duration of the test is dependent upon the type of vehicle per table 26 and the energy level GRMS has been measured the location of interest GENERAL MOTORS CORPORATION EDSON 2008 Procedure Monitoring Constant monitoring during the entire test is required to detect intermittent failures of electronic devices and the onset of cracks in brackets Operating Type The test shall be performed under operating type 3 2 if electronic Test the DUT for the required number of hours in each direction using the appropriate Sample size to demonstrate the required level of reliability Thermal cycling should occur during the time of the vibration test as described in the other vibration tests in this document Criteria The bracket or device must demonstrate a reliability of R 97 with Confidence 50 using the test derived from the process described above One Hour Vibration Test After Thermal Fatigue Purpose This test is used to detect intermittent failures that may have been created during the thermal cycling and humidity tests This one hour test is not intended to add damage to the product but is only intended to be a detection process Vibration at all temperatures is the requirement and this should be accomplished in as short of a time as possible Typically this is one hour or less Locations of Applicability This tes
360. s the average time to failure for the total product Conducted As An Accelerated Test Limit of Patch It Up And Keep Technology Equals Testing Design Maturity Weak Failed Cap Strong LL X KKK 2 Time Test The objective during the development phase is to eliminate the low hanging fruit weaknesses that would have reduced the efficiency of testing during Validation This does not mean that Validation Testing is not necessary because even though we reduce product life variability a good thing we still do not know if we are good enough The concept of good enough is shown as the difference between the first pair of rows and the second pair of rows in the following graphic Developing Design Maturity To Reduce Variability Requirement During Testing Immature Design AA A Case 1 Good Enough Mature Design B PA Case 2 Immature Design With Weak Materials NOT Good aan Enough Mature Design With Weak Materials Ak NS ees Case 4 Case 3 GENERAL MOTORS CORPORATION EDSON 2008 85 VALIDATION TASKS Validation introduces the world of statistics and time based correlation to the test plan We call these tests Quantitative Tests as they not only address the qualitative nature of the product but they also establish the quantitative aspect of when in time failure is expected to occur There are three major failure mechanisms that are quantitatively addr
361. s to be run on every product GENERAL MOTORS CORPORATION EDSON 2008 10 11 Learn what each code letter means by reviewing tables 2 through 7 Every test will have a corresponding Operating Type code and Functional Status Classification code You must learn and understand these codes As you need additional knowledge regarding each individual test look for the Wizard and the Wizard s Words which will add background and explanation for each test A review of the ADV Plan Overview will provide the background of the strategy behind GMW3172 It all boils down to one simple fact You must behave as if you were the only person responsible for the reliability of your product only you L Edson Why I Am Showing You Optical Illusions And Poetry To Accompany The Hardcore Science and Math We all live with the illusion of boundaries that we cannot cross Then some brave soul crosses one of those boundaries and reveals the can t as only an illusion Illusions span our personal lives as well as our work lives Remember there was a time when many thought that the earth was flat and a time when it was thought that your lungs would explode if you ran faster than a 4 minute mile and again there was a time when it was thought that an accelerated test was interesting but not realistic Every illusion meets its day of reckoning as the pursuit of truth is relentless The truth will stand firm as the
362. s will result in an acceleration factor for lead free solder while faster ramp rates will result in an acceleration factor for leaded solder Ramp Rate Acceleration Factor 1 22x Ramp Rate 0757 Ramp Rate Acceleration Factor 1 22 7 0757 1 02735 gt Step 12 Lead Free Acceleration Factor For The Maximum Temperature Used During Testing The maximum temperature used during testing can have a significant effect on the amount of creep that occurs during the thermal transition Creep occurs much faster at higher temperatures In this example we will use a 95 high temperature during thermal shock to accelerate the test and we are not worried about functioning at this temperature because we do not energize the device during thermal shock 1 1 e Highest Temperature Acceleration Factor e 273 273 Highest Temperature Acceleration Factor z 1 PTC Step 13 Lead Free Total Multiplication of Acceleration Factors 2 65 136 m 1 1 2 x 1 22x ramprate x Dwell time Combined Acceleration Factor 16 909 x 815 x 1 02735 x1 14 158 1825 14 158 128 9 Number of Cycles GENERAL MOTORS CORPORATION EDSON 2008 288 289 gt Step 14 Lead Free Accounting For The Reduced Sample Size We must now increase this value by 1 124 to compensate for the fact that we are only using 18
363. sign margin How will these parameters be controlled in production o What improvements can be made at each stage of product development for areas with low design margin and how when will we know that these improvements were effective o How should the test plan be modified in the next phase based on the results learned in the previous phase My alphabet starts with this letter called YUZZ It s the letter use to spell Yuzz a 22 You ll be sort of surprised what there is to be found Once you go beyond Z and start poking around 50 on beyond Zebra Explore Like Columbus Discover new letters Like WUM is for Wumbus My high spouting whale who lives high on a hill And who never comes down til it s time to refill So on beyond Z It s high time you were shown That you really don t know all there is to be known Dr Seuss Beyond Zebra GENERAL MOTORS CORPORATION EDSON 2008 2 4 Appendix Success Run Statistics Calculating The Number Of Samples To Be Placed On Test To Demonstrate The Reliability Requirement Equation 1 Success Run Equation 1 R 1 C This equation can be transformed into equation two as shown below Equation 2 Sample Size Equation In 1 C In R Where the required reliability to be demonstrated on test C the Confidence level the sample size Nreduced the new reduced sample size For Example If R 0 97 and C 0 50 then
364. son Acceleration Factor E23 17 465 field gt Thermal Shock Step 3 Leaded Solder Applying The Acceleration Factor For Dwell Time Effect To The Thermal Shock Cycles We are using an optimum damage per unit of time dwell period during testing of 10 minutes both hot and cold While this is optimum on a per unit of time basis it does not encompass all of the damage that would have been generated by the severe customer using a longer dwell period The following acceleration factor accounts for the lost damage with a shorter dwell period Dwell Effect Acceleration Factor 768x min Dwell Effect Acceleration Factor 768x 4 842 gt Thermal Shock Step 4 Leaded Solder Acceleration Factor Resulting From The Thermal Ramp Rate The use of faster thermal ramp rates in making the temperature transitions on leaded solder produces an acceleration factor greater than one This factor is derived from the modeling work of J P Clech and is shown in figures 14a of reference 14 Slower ramp rates will result in an acceleration factor for lead free solder while faster ramp rates will result in an acceleration factor for leaded solder Ramp Rate Acceleration Factor 80094x Ramp Rate 0964 Ramp Rate Acceleration Factor 80094 1 gm 1 04 Thermal Shock Step 5 Leaded Solder Acceleration Factor For The Maximum Temperature Used During Testing 293 GENERAL MOTORS CORPORATION EDSON 2008 maximum te
365. sonance value While the above equation relates the input vibration variables the output vibration takes on the following form _ Gx9 8xQ Yo f The value of Q as a function of a span of frequencies about the resonant frequency is shown in the following graphic The Q Factor Effect At Different Frequencies Resonance And Maximum A Displacement 20 Displacement _ Q 77 factor Displacement Q factor 1 1 2 1 1 5 Ratio Of Input Frequency Resonant Frequency resonant You can see that the Q value has an effect from about 72 of the resonant frequency to 1 times the resonant frequency The Q value for a circuit board can be approximated by the following equation GENERAL MOTORS CORPORATION EDSON 2008 76 Q 5 h y Where e f resonant frequency e Gin input gravity units acceleration dimensionless THERMAL FATIGUE A change in temperature produces stress between two bonding materials when those materials have different coefficients of thermal expansion CTE Under these conditions temperature cycling produces cyclical stress which becomes thermal fatigue The cumulative molecular damage that results from thermal fatigue produces increasing weakness with the accumulation of thermal cycles until eventually the material fails Such a failure would not occur when the first or second thermal cycle was applied Stress Resulting From
366. specification is 409 to 85 C delta T of 125 C The Coffin Manson Equation gives us the equivalent damage relationship Coffin Manson Acceleration Factor E at field Note m 2 65 for lead free solder Solder represents worst case in terms of the m values and that will be the target material used in this document m 2 65 Coffin Manson Acceleration Factor 16 909 field gt PTC Step 10 Lead Free Solder Applying The Acceleration Factor For Dwell Time Effect To The PTC Cycles We are using an optimum damage per unit of time dwell period during testing of 10 minutes both hot and cold While this is optimum on a per unit of time basis it does not encompass all of the damage that would have been generated by the severe customer using a longer dwell period The following acceleration factor accounts for the lost damage with a shorter dwell period Dwell Time Dwell Time Acceleration Factor Dwell Time 10 136 Dwell Time Acceleration Factor 2 815 287 GENERAL MOTORS CORPORATION EDSON 2008 gt PTC Step 11 Lead Free Acceleration Factor Resulting From The Thermal Ramp Rate The thermal ramp rate used in making the temperature transitions has a small effect on lead free solder I have included the equation for this effect for completeness of the model This factor is derived from the modeling work of J P Clech and is shown in figures 15a of reference 14 Slower ramp rate
367. ssenger and trunk compartment should provide a water shedding case design so that dripping or splashed water will not affect the electronics Consider the fact that the connector is usually designed to be mounted in a downward facing direction If you were to park the car on a hill then it could be possible that this connector would be facing in a more upwards direction than it would if parked on a horizontal surface The product should be tested as if it was oriented while parked on a worst case incline of 14 2 degrees worst case per San Francisco Note A 45 degree angle is considered a 100 grade o Shown below according to the city Bureau of Engineering are the steepest roads in San Francisco in descending order pun intended 1 amp 2 Filbert between Leavenworth and Hyde 22nd Street between Church and Vicksburg both 31 5 percent gradient GENERAL MOTORS CORPORATION EDSON 2008 3 Jones between Union and Filbert 29 percent 4 Duboce between Buena Vista and Alpine 27 9 percent 5 amp 6 Jones between Green and Union Webster between Vallejo and Broadway both 26 percent 7 amp 8 Duboce between Divisadero and Alpine Duboce between Castro and Divisadero both 25 percent 9 Jones between Pine and California 24 8 percent 10 Fillmore between Vallejo and Broadway 24 percent Using the above information we can compose the following example o A device mounted inside the vehicle is designed such that the con
368. st No individual circuit shall have more than 20 milliohms of resistance at the beginning of the test GENERAL MOTORS CORPORATION EDSON 2008 216 contacts shall meet the criteria for resistance connection point defined in GMW3191 Reliability as determined by the Weibull plot shall be quantified for each of the critical circuits with a sample size of six for each plot and a plot for each of the critical circuits No circuit shall develop an increase in resistance that is more than 3 times that circuit s original resistive value Fretting Corrosion Degradation Test Starting Resistance Values Are Normalized To 100 Failure Is Considered To Be 30096 30096 S Design S Margin O 100 Vibration Level Time During Vibration Test Weibull Probability Dependant Upon odd Mounting Location 24 Hours Of With Thermal Cycling Vibration Weibull Analysis Of Fretting Corrosion Degradation Test Data Weibull Analysis Of Fretting Corrosion Data 99 90 90 00 Weibull Data 1 W2 RRX SRM MED F 6 5 0 Iq 1 50 00 The Probability Of Some Portion Of The Distribution Exceeding 300 15 Less Than 396 9796 Reliability Cumulative Distribution Of Increased Resistance WENMENENNNHNNNNNENNENN Larry Ed
369. st Appendix 423 This checklist is essential at the beginning of the program to make sure that the supplier has full understanding of the impact of becoming lead free The supplier should be directed to the INEMI website www inemi org for tutorial information on lead free design and manufacturing GENERAL MOTORS CORPORATION EDSON 2008 142 eee Program Analytical Tasks Mechanical Analysis Circuit Board Or Other Critical Element Resonant Frequency Analysis 9 This analysis is important if there is a large circuit board or if there are large mass items that do not seem to be well supported Resolve these issues early in the program This analysis may be skipped if the circuit board is small and very well supported including the center High Altitude Shipping Pressure Effect Analysis The High Altitude Shipping Pressure Effect analysis is necessary when a device is hermitically sealed and may rupture or lose its seal when transported in a low pressure environment as occur in the luggage area of an airplane Snap Lock Fastener Analysis Appendix 25 This analysis is required when there will be plastic snapfit attachments that have not been previously field proven or if the snapfit design will be used with high mass and high heat The analytical process described in Appendix N will assist the engineer in designing a bracket that will adequately support an electronic de
370. st code 8 in the table above must pass 15 submergings Code 9K The 9k test is intended for underhood only applications and represents the effects of steam cleaning the engine compartment All devices under the hood that could be directly sprayed should receive a code of Devices under the hood that are protected from direct spray should receive a code of 6K Devices mounted where they could be sprayed car wash and submerged as when backing boat into the lake should be assigned the code 6K and the Seal Evaluation Test code number 8 should also be required Special Notes The dust test can be relocated in the test flow to become a pre treatment prior to mechanical cycling of a mechanism that may experience wear The dust test can also be relocated in the test flow to become a pre treatment prior to the high temperature durability test This may be done in order to evaluate the possibility of overheating resulting from dust clogging critical convective heat transfer elements in the design The product should be powered immediately following the completion of the water test to ensure proper function Products should be designed to shed water and in all cases make sure that water is directed away from the circuit board Good dissection at the end of the test is critical in detecting water on circuit boards No water must ever reach the circuit board or the critical components either by drip splash or spray Water must no
371. st to evaluate the proper function of flash memory programming Criteria Programming should occur properly with the inductance in place FSC A DEVICE STATE CHANGE WAVEFORM CHARACTERIZATION The quality of the waveform during state changes such as startup and shutdown is important regarding hardware to hardware interactions hardware to software X interactions This requirement has been introduced as a result of problems seen by the electrical community where noisy signal is sent the downstream devices during the initialization of the product with resulting problems State change is defined as the energizing or de energizing of the device during power up wake up power down or all of the above The CTS should define the level of noise that is acceptable during this state change period Purpose This procedure is used to characterize the transient waveform produced by the device during critical state change events The output is reviewed in graphical form and a risk assessment to downstream devices is performed One consideration in analyzing the waveform is to detect inadvertent actuation of outputs Locations of Applicability locations Procedure A capture of output waveforms during state change should occur on several samples of the product A waveform should be captured for each state change considered critical See the CTS for details of capture duration and crite
372. t accumulate within the case and then be allowed to reach the circuit board A Door Zone Module smart switch or similar device such as the mirror switch should receive additional water drip testing to ensure GENERAL MOTORS CORPORATION EDSON 2008 that the design properly deflects water away from the circuit board as well as critical elements in the switch system The IP5K3 test that would be typically called out for this device should be expanded into a 4 code The test should use water that has UV dye added and the water should be dripped on to the switch as defined in the 2 code Water should be dripped for 30 minutes as opposed to the standard 10 minutes The switch exterior should be wiped dry and then the switch should be closely scrutinized with a black light to detect possible destructive water paths within the device A simulated armrest environment should be used during the water drip process General Motors uses a subset of the International Protection Codes The coding behind the IP definitions is similar to ISO20653 requirements for dust and water intrusion The following example explains the use of letters in the IP Code Example Code Letter IP 5K 2 International Protection First Element For Dust Second Element For Water GENERAL MOTORS CORPORATION EDSON 2008 114 Table 7 International Protection Codes First IP Code Element Dust Degree of protection for Dust First code Brief e
373. t higher stress levels to establish the stress life relationship line on log log paper allowing estimation of life at normal stress through extrapolation of the stress life line This basic concept made popular by Wayne Nelson was improved upon by using two different high stress level tests to estimate the lowest stress that could be used a third stress level to meet test timing requirements Three different stress levels are then used to provide the best estimate of the stress life line This final stress life line is then used to estimate life at the normal stress level This methodology is documented GMW8758 and was developed by Edson Graphical Explanation Of The CALT Process IPL Weibull Life Data 1 Time hours ta 10000 00 Test Two or More 1000 00 Available o Requirement Time Test Two L N Third Stress Level Test Two 10 00 Identified Stress t Foolish Stress Level Normal Stress Level Figure 8 CALT Testing Explained 69 GENERAL MOTORS CORPORATION EDSON 2008 DEGRADATION ANALYSIS Measuring the degradation of an important parameter over time and extrapolating as to when in time it would become unacceptable This process can be carried out at different stress levels using the CALT process and the combined effect can result in hi
374. t is applicable to all devices following thermal fatigue and humidity Procedure A full hour may not be needed for low thermal mass products There is no need to dwell at the temperature extremes other than to ensure that the product actually reaches the target temperature Constant monitoring is essential during this test The product may be pre chilled to Tmin and the vibration run while the product transitions to Tmax full thermal cycle is not required cyclic reduction in vibration level 15 suggested 2 84 down to 5 and back up to 2 84 for a sprung mass to assist in detecting intermittent failures Criteria No intermittent failures are allowed and the product should function as if the stress of temperature vibration was not present EVALUATION OF SQUEAKS AND RATTLES FOLLOWING VIBRATION WITH THERMAL CYCLING General Motors has published more complex squeak and rattle evaluation procedures GMN14011 that may be used if required for devices such as radios but the increased complexity GENERAL MOTORS CORPORATION EDSON 2008 234 235 significantly increases cost and test time This simple procedure described below should be used for most electronic devices that are more remote from passenger s ears Testing by shaking with your hand may seem to be very subjective but this can be more effective than testing on the shaker as the shaker makes so much noise that it becomes very diff
375. t x 1 22 x ramprate 0757 x 273 Thestmax 273 AT s Dwell Coffin Manson Portion of the Modified Norris Landzberg Equation for 2 65 lead free solder ES field GENERAL MOTORS CORPORATION EDSON 2008 242 243 When it the equations described in Appendix B is desired to reduce the sample size and extend the test duration use assumed it is advised to use a value Beta between 1 5 and 2 Figure 40 Thermal Cycle Profiles In Arizona Engine Southern Arizona July Mounted Engine Mount 7 Engine Compartment T Interior Engine 4 Compartment E 5 E 4 4 ATI 51 67 79 43 35 3791 3125 98 7245 46 34 4178 3428 102 72 76 05 75 49 48 83 4417 3639 80 04 5281 47 66 mn 39 61 aoma 78 5093 4454 111 41 6143 _ 41 13 46 41 2641 21 00 2 6146 _ 29 49 40 60 18 93 E BHO P L ATI 16 44 16 99 10 79 19 43 20 86 5 25 25 91 24 52 6 74 95 84 71 39 70 28 45 84 29765908 101 05 76 05 73 83 48 83 4151 35 56 99 50 74 50 72 83 47 83 4177 3483 88 52 65 19 65 19 41 z S 29 59 80 20 57 43 59 65 36 87 148 48 25 64 UO o o 50 D 9 50 c ac o i z 4 e 2 E o E Em 5 Fatigue Property m Engine Mounted
376. tallation of the seats will be at risk from being stepped on when other assembly operations are performed If you cannot design the product to pass this test then you better not put that product now or in the future on the floor of the vehicle Purpose Evaluate bending force weaknesses of the connector or circuit boards to which the connector 15 attached These human applied forces may be the result of side forces during connector attachment or misplaced forces from a person s foot during other assembly operations This test is only applicable to connectors with at least 13 mm of area contained in a circle Locations of Applicability This test is applicable to devices any where on the vehicle where a person could step upon the device during assembly or service Monitoring Evaluate for damage and function at end of test Operating Type test shall be performed under operating type 1 2 The final evaluation shall be performed at the end of the test under operating type 3 2 Functional Status Classification This represents foot load that possibly occur during vehicle assembly The connector header system shall withstand without electrical degradation or permanent physical damage a simulated foot load of 890 N of a distributed force applied normally through a 50 mm x 50 mm or appropriately sized rigid steel plate for 1 min as shown in the Connector Integrity sketch This
377. ted Load 1 to Load n and the output currents driven in the 202 full range from load min to The functional status shall be class I load max for each Us step during and after the test No fault The Uo waveform will depend on the codes shall be generated during or frequency 1 2 100 2 and 4 kHz after the test shown below for the case Us 14V Criteria uo_100hz 85ms 87ms 89ms 91ms 93ms 95ms 97ms 99ms 101ms 103ms 105ms 340 6ms 340 8ms 341 0ms 341 2ms 341 4ms 341 6ms OPEN CIRCUIT if the module design will allow any output circuitry to be left in a partially active state when all logic power or grounds become open circuit When these circuits are not completely turned off or completely turned on they function much as a resistor and can become overheated and eventually become inoperative The following version of the Open Circuit Test is suggested based upon validation experience in 2007 The duration of the open circuit test time has been extended compared to previous time The following special Open Circuit tests are to determine 203 GENERAL MOTORS CORPORATION EDSON 2008 Open Circuit Signal Line Single Interruption Purpose Determine if the device is able to suffer no damage due to incomplete contact conditions and to determine if the part functions properly immediately after the completion of the contacts Locations of Applicability All locations
378. ted foot load of 890 N of a distributed force applied normally through a 50 mm x 50 mm Or appropriately sized rigid steel plate for 1 min as shown in the following figure Locate the steel plate on top of the DUT and apply the 890 N to the top of the device through the steel plate Figure 18 Foot Load Applied Method B To Top of Device Housing Foot Applied Force To Case Normal Force Applied In The Middle Of The Steel Plate 50 mm X 50 mm Steel Plate Bridging The 2 Gap Between and D DUT Case Fastened To Support Header Structure UA orum Connector D Vehicle Support Structure Represents The Vehicle s Floor Pan or Bracket GENERAL MOTORS CORPORATION EDSON 2008 Criteria The device should function properly following the application of the above stress levels physical damage Should be evident which may lead to subsequent failure with vibration induced stresses Functional Status Classification C CONNECTOR INSTALLATION ABUSE The Connector Installation Abuse Test is intended to ensure that a robust design is used so that stresses applied in the assembly plant during installation do not result in product damage Purpose Evaluate bending force weaknesses of the connector or circuit boards to which the connector is attached These human applied forces may be the result of side forces during connector attachment
379. ted using the 5 point temperature and voltage evaluation prior to any other testing We want to make sure that we are starting with parts that work at all necessary temperatures and voltages Items in the test flow that are shown using a dashed box are optional tests and may be required for some products and not for others SMART SWITCH TEST FLOW A test flow for leaded and lead free smart switches is also shown These test flow show a suggested combination of GMW3172 and GMW3431 Smart switches are vulnerable to the failure mechanisms of both electronics and switches and thus a combined test plan is necessary GENERAL MOTORS CORPORATION EDSON 2008 130 ajajdio4 7 111891 5 10 51304 AL ajajdwon AACO PTT 13 5 1 jeuondo 5534 uonsadsu ensi uolsss 10 3uaurdo aanar uj uny ag Aep sisay 2 55 0 pue uon2essi pug onis 3591 jus4n 7 484 O 0788 OS AS ensiA uonosedsu ensiA poe id uonasedsu USITEIGIA JO pZ 9euL juae dui Aas 5 51591 2LSUIEJE 5459 21 IEnSIA Buung Bupunaso 06 y 9914891 euonoun4 tell j ak
380. ternating Voltage Beyond Normal Levels Pulse Superimposed Alternative Voltage Within Normal Levels Open Circuit Signal Line Single Interruption Open Circuit Signal Line Multiple Interruption Open Circuit Battery Line Interruption Open Circuit Ground Line Interruption Ground Offset Power Offset Intermittent Short Circuit M C Continuous Short Circuit M C Ground Interconnect Short To Battery M C Load Circuit Over Current Modules M C Load Circuit Over Current For Bused Electrical M C Centers GENERAL MOTORS CORPORATION EDSON 2008 150 lll EN Program Isolation Resistance Electromagnetic Compatibility f Connector Tests GMW3191 Dec 2007 Connector Tests 1 Terminal Push out section 4 8 M C 2 Connector to Connector Engage Force M C section 4 9 3 Locked Connector Disengage Force M C section 4 12 Unlocked Connector Disengage Force M C section 4 13 Connector Installation Abuse Fretting Corrosion Degradation R 97 and C 50 Intended to be used only for Bussed Electrical Centers or special situations Mechanical Tests Vibration With Thermal Cycling M E Reliability Demonstration required 97 amp 50 ME Lo Vibration With Thermal Cycling meme ua _ sera ee Door Trunk Hood Slam i Crush Test For Device Housing FreFal EM GENERAL MOTORS CORPORATION EDSON 2008 2 d Program Tempe
381. tes and the highest value of the peak generated by the DUT must be within the capability of the measuring device The DUT should be equipped as installed in the vehicle All inputs outputs and sensors are to be electrically connected and in their normal inactive state 1 Connect the DUT to variable power supply and adjust the input voltage to 12 volts The system should be at a temperature of 25 C 2 Place the system into OFF mode 3 Measure the current in the system over a time frame for a period that is ten times longer than the longest expected periodic repeated event of the module Certain modules may experience periodic or occasional wakeups when OFF OFF Awake The current when in OFF Asleep and under all OFF Awake conditions should be recorded 4 While measuring the current decrease the supply voltage by 1 volt minute until one volts is reached The criteria must be met throughout the decreasing voltage process This process is looking for abnormal behavior of the device to a reduction in voltage The current draw should gracefully lessen or remain the same as the voltage source is reduced Figure 25 Parasitic Current Evaluation Good and Bad Behavior With Decreasing Voltage Parasitic Current Evaluation With Decreasing Voltage X X Parasitic X Parasitic X 12 Volts Supply Voltage Measure The Average Steady State Parasitic Current Draw In This One Minute Time Interval Wh
382. test Test according to IEC 60068 2 56 Cb With the following exceptions Table 31 Constant Humidity Test Requirements Relative Humidity 85 95 Special Note This test can be accelerated through the use of the Arrhenius Peck equation with the temperature not to exceed the service temperature of plastic components This represent significant reduction in test time Optional If fungus growth is a concern then this test should be run at 42 C for 21 days This cooler and longer test may be applicable when new materials fluxes being introduced Criteria Functional Status shall be class A The parasitic current that is measured during the test should not increase beyond that allowed by the parasitic current test CORROSION TESTS The Salt Corrosion Tests are intended to do the following Interior Mounted Devices Salt Mist Test e Evaluate for proper function in a salt water laden air environment Evaluate for proper function when salt water may drip upon the device Evaluate for proper function following cleaning at the end of the 3 to 10 day test Evaluate for base metal corrosion that may lead to loss of critical connections or circuit function Exterior Mounted Devices Salt Spray Test GENERAL MOTORS CORPORATION EDSON 2008 Corrode water path openings into sealed containers allowing water to reach the circuit board Corrode connector
383. that are to be evaluated in Validation and will reveal the same failure modes but will not contain the time based correlation that exists in Validation We call these tests Qualitative Tests as they only address the qualitative nature of the product Development is a time of very small Sample sizes 1 3 and the objective is to discover unexpected weaknesses The following graphic shows the basic developmental testing strategy identify the varying inter arrival times of different failure modes and eliminate those GENERAL MOTORS CORPORATION EDSON 2008 weaknesses that will provide the greatest return investment by their removal You can see that you will reach a point of diminishing return as more and more weaknesses are removed The decision of when to stop eliminating weaknesses during development will be driven simply by return investment Product improvements at this point in the program are going to be much less expensive than during Validation Learn fast learn with least cost How Affect Reliability During Development Accelerated Reliability Growth a Testing a single sample each star will probably be a different failure mode Fix a failure mode and the expected overall variability in the total product decreases Uncovering weaknesses by one until the limit of technology is reached many things fail at the same time a Removal of low hanging fruit from a relative point of view improve
384. the probability that the logic circuit does not falter when encountering interaction problems with hardware or external media CDs etc The Fault Injection Test is the result of the CD player radio not being robust against the use of damaged media or extreme customer use random excessive button pushing Robustness evaluations are intended to confirm that the device Does What It Is Supposed To Do and Does Not Do What It Is Not Supposed To Do An example of this problem may be when a product shuts down or locks up when confronted with minor GENERAL MOTORS CORPORATION EDSON 2008 180 181 abnormality or behaves an unsafe or unstable manner These procedures are to be performed as development and validation activities Purpose Fault injection testing consists of a systematic series of evaluations where hardware and or software elements are purposefully disrupted disabled or damaged in order to test and grow the robustness of the whole system to deal with abnormalities Locations of Applicability Devices that will have direct interactions with people Procedure Monitoring To be monitored continuously during the test Operating Type Operating type is 3 2 See Appendix N Criteria Verify that an E E device is tolerant of potential system abnormalities The FSC A MECHANICAL TESTS IN DEVELOPMENT HIGHLY ACCELERATED LIFE TEST HALT The HALT test should be p
385. the recovery time and diagnostic data for the test report and note any observation of abnormalities exhibited by the device under test Fault Injection Testing Purpose Fault injection testing consists of a series of evaluations where hardware and or software elements are purposefully disrupted disabled or damaged in order to test and grow the robustness of the whole system to deal with abnormalities The ultimate goal is to verify that an E E device is tolerant of potential system abnormalities This requires that 1 The device will not be physically damage by an abnormal input or output 2 That operation of the device will remain stable and ensure safe vehicle operation 3 If the abnormality or disruption is removed the device will resume normal operation NOTE The GMW3172 short circuit endurance tests are the primary procedures for verification that the device is not physically damaged by system 313 GENERAL MOTORS CORPORATION EDSON 2008 abnormalities The fault injection procedures focus on functional stability during abnormalities When possible fault injection evaluations may be performed in combination with the physical short circuit tests or they may be performed separately after the short circuit tests have confirmed the physical capabilities Preparation Prior to performing this procedure a mechanization review of the device s internal and external hardware and software is required in order to organize the d
386. tion 12 Giacomo Giulio et al CBGA and C4 Fatique Dependence On Thermal Cycle Frequency 2000 International Symposium on Advanced Packaging Materials 2000 13 Clech Jean Paul SAC Solder Joint Reliability Test Conditions and Acceleration Factors SMT Hybrid Packaging Conference Nurnberg Germany April 19 2005 14 Clech Jean Paul Acceleration Factors And Thermal Cycling Test Efficiency For Lead Free Sn Ag Cu Assemblies SMTA International Conference Chicago Il September 2005 t gt Kurdian Ishkan Learning To Take It Easy When Giving Birth To World Class Reliability International Conference On Test Development GME Engineering Center Russelsheim Germany 2005 16 Henshall Greg et al Hewlett Packard An Acceleration Model for Sn Ag Cu Solder Joint Reliability Under Various Thermal Cycle Conditions SMTA International Conference Chicago Il Sept 25 29 2005 you say This is really great stuff And guess the old alphabet ISN T enough NOW the letters use are something to see Most people still stop at the Z But not me L Edson A Day In The Life GENERAL MOTORS CORPORATION EDSON 2008 322
387. tion Profile For Sprung Masses Body or Chassis Mounted Random Vibration Profile 100 10 1 m s Hz 0 1 0 01 10 100 1000 Frequency Hz Sprung Mass RMS Acceleration 27 8 m s rms 2 84 Grms Criteria Functional Status shall be class A through out the test objectionable squeaks rattles should be present before or after the test The responsible GM engineer Should evaluate the severity of all Squeaks and rattles that develop following the vibration test The criteria for a mounting location that is close to the passenger s ears should be more discriminating than for locations farther away Table 24 Random Vibration Profile For Sprung Mass Power Spectral Density g Hz Frequency Acceleration Power Density m s Hz Random Vibration Mounting Location Unsprung Masses Purpose This test is applicable for devices which are mounted on unsprung masses e g wheel and wheel suspension Vibration of unsprung masses is random vibration induced by rough road driving Locations of Applicability This test is applicable to all devices attached to the wheels tires and moving suspension elements of the car or truck Procedure Monitoring Constant monitoring during the entire test is required to
388. tion energy 301 GENERAL MOTORS CORPORATION EDSON 2008 Appendix Accelerated Humidity Testing The effect of Humidity results in a mixture of failure mechanisms that are intrinsic to automotive use HAST is a highly accelerated humidity diffusion test that can only operate above 106 C This test is intended for electronic circuit boards and electronic components This test is not intended for plastic electronic assemblies because the temperature in this test exceeds service temperature for most common plastics This high stress environment will accelerate the effects humidity and temperature according to the Arrhenius Peck relationship as shown below A HAST test operated at 130 C and 90 R H provides the following acceleration factors 1 day of HAST is equivalent to 21 days of 85 85 or 1 day of HAST is equivalent to 97 days of 65 85 or 1 day of HAST is equivalent to 1414 days of 35 85 Ten years of the effect of humidity for the ingress of water vapor into components and circuit boards can be accomplish in approximately two days of HAST testing at 130 C and 90 The use of the Arrhenius Peck gt stress life math model suggests that this is equivalent in damage to 4656 hours of 65 C at 85 R H or 194 days of constant humidity testing as defined in this document Equally damaging tests of lower temperature longer durations are permitted through use of the Arrhenius Peck relationship as n
389. tion tests The temperature cycle profile used during the test should be according ISO 16750 3 General The DUT shall be operated continuously monitored Operating Type 3 2 throughout the thermal cycle Optionally the device can be turned off for periods of one minute during the hot cold and transition periods to evaluate the ability of the product to return to function under the condition of vibration with different temperatures In the case where self heating components may cause a problem a deviated operating mode can be established with the approval of GM Engineering Figure 35 Thermal Cycle Applied During Vibration 80 Power Off 60 Interrupts Thermal Cycle During Vibration Power Off Interrupts of 1 Minute Occur During Cold Hot and Transitions Temperatures Are To Extend From T nax To T nin 20 p 0 Powered and Monitored Powere d and Monitore Powered and Monitored Powere d and Monitored Temperature Celsius 0 60 120 180 240 300 360 Time Mnutes For One Thermal Cycle 20 The graphic shown portrays an eight hour thermal cycle A six hour thermal would have the dwell periods reduced proportionately A one hour thermal cycle would have no dwells and an increased ramp rate 420 480 GENERAL MOTORS CORPORATION EDSON 2008 230 Table 20 Time vs Temperature for Figure 37 Slip Table Type Shaker Vibration
390. tive at producing diffusion through plastic encapsulations Purpose The cyclic temperature humidity test is designed to reveal defects in test specimens caused by the ingress of humidity and moisture condensation The breathing effect produced by changes humidity condensation resulting from changes temperature and the expansion effect of freezing water in cracks and fissures are the essential features of this composite test Locations of Applicability This test is applicable to all areas of the vehicle Procedure Monitoring Continuous quiescent current is monitored for every DUT over the 10 day test period to detect malfunctions during the test Operating Types Heat producing device Operating Type 3 2 with device power cycled on and off to balance ingress of moisture and condensation formation with ability to detect malfunction Non heat producing device Operating type 3 2 with device constantly powered Test according to IEC 60068 2 38 Z AD Table 30 Cycling Humidity Test Requirements Dun 65 Low Temperature Middle 425 Temperature The following graph figure 45 shows a two day cycle that is to be repeated a total of five times 2 X 5 10 days Temperature 18 C The humidity during high temperature is 90 96 and drops to 80 during times of 25 C The humidity is uncontrolled when cold Figure 45 Cyclic Humi
391. tlet Power Supply B Ground Ground 1 8 Volts Negative Ground 2 0 Volts 1A Swap Ground nd Negative Ground 2 To Produce Opposite Voltage Effect 207 Ground offset between platform modules and the powertrain 1 Apply Umi to the DUT 2 Subject ground line toa 1 0 V offset relative to the DUT ground 3 Perform a Functional Parametric Test under these conditions 4 Repeat for next ground line 5 Repeat for lines simultaneously 6 Repeat for a 1 0 V offset 7 relative to the DUT ground 8 Repeat 2 through 6 at Umax Criteria The functional status shall be class A POWER OFFSET The Power Offset Test simulates the condition where different power feeds into a device may have slightly different levels of voltage potential This could result from different length feed wires or unbalanced loading of power feed lines Purpose This test shall also determine if the device functions properly when subjected to power Offsets GENERAL MOTORS CORPORATION EDSON 2008 Locations of Applicability All location on the vehicle but only devices that have more than one power line Power lines could be input from ignition or direct battery Procedure Monitoring Continuous monitoring is required to detect intermittent faults Operating Type The test shall be performed under operating type 3 2 The test Setup For Power G
392. ty vibration 2WD Full Size Truck PU or Utility 600 hours of vibration 4WD Mid Size PU amp Rec Off Road 150 hours of vibration 2WD Mid Size PU amp Rec Off Road 150 hours of vibration 4WD Mid Size Utility 150 hours of vibration 2WD Mid Size Utility 150 hours of vibration Mid Size SUV and Van 125 hours of vibration 84 hours of vibration Passenger Vehicle Resonant Frequency A good design criterion for brackets is to design the bracket to have a resonant frequency greater than 150 Hz These design criteria would apply to the bracket without the product attached Meeting this criterion will help insure that there will not be any problems with bracket fatigue Measured Fatigue Life The bracket supporting the mass of the DUT shall meet the R 97 and C 50 requirement using appropriate sample size or test to failure Cracks or deformation shall not occur at the point of reliability evaluation Purpose Evaluate bracket fatigue life over the full range of temperatures The brackets used in attaching electronic devices are not being evaluated in the vibration tests defined previously The amplification Q factor resulting from the attaching bracket has already been factored into the GRMS values specified Brackets should be evaluated separately using a reduced level of vibration to be defined in the ADVP amp R or Test Template Locations of Applicability Thi
393. velopment and validation GENERAL MOTORS CORPORATION EDSON 2008 46 E ES i 15 ier i mig y rd A A M a 7 LR NK TA 74 ev A kt x E AS Gest Pictures Showing Tin Pest On Tin Copper Bars Stored At 18 C Alpha Phase Of Warts Of Alpha Tin As A Phase Tin Crumbly Gray Appearing On Substance Beta Phase Tin KIRKENDALL VOIDS Kirkendall voids are the formation of physical voids in the material usually copper as a result of metal migration away from the local area Temperature is the accelerator of this phenomenon An example of this problem occurs when copper is placed in direct contact with tin The copper tends to diffuse into the tin leaving a layer of voids at the interface of the copper tin Kirkendall Voids Develop At The Interface Of The Different Materials In The Metal Structure 4 GENERAL MOTORS CORPORATION EDSON 2008 TIN WHISKER FORMATION Tin whisker formation is the spontaneous growth of fine crystals of tin outward from the surface of the tin plating without the need for high levels of stress or usage Theory has it that the growth of the whiskers is an internal response to reduce compressive stresses in the tin layer Tin whiskers can be inspired to form with a pre treatment of humidity followed by simple thermal cycling over a center point of 13 C
394. vice without fracture over the life of the vehicle This analysis should begin early in product development and will allow the designer to design in the required level of reliability 143 GENERAL MOTORS CORPORATION EDSON 2008 ee M ain Program Crush Test Analysis 3 When a circuit board with a tall capacitor is designed too close to the surface of the case it becomes possible for a misplaced elbow to deflect the surface of the case and cause a bending action to the circuit board FEA analysis is frequently used to determine the extent of case deflection with the given loads defined in this document Temperature eee Altitude Operation Overheating Analysis This analysis is necessary when a device is heat generating and uses convective cooling methods for heat dissipation Air at high altitudes is significantly less dense than air at sea level and this fact will significantly diminish the ability of convective cooling designs to perform as intended Thermal Fatigue Analysis This analysis is necessary when large surface mounted components are attached to the circuit board large differential in the coefficient of expansion between the component and the circuit board will result in high stress in the solder attachments Use FEA or Dave Steinberg s calculations to perform this task see reference list in 1 72 Analytical Results Review Results Review of Analytical Tasks DRBFM
395. wer mode the ECU is powered for 1 minute note this is beyond 40 days During the time the module is on it draws 350 mA When in the off state the module draws 0 200 mA Both current ratings apply at 259C and 12 6 volts The answer sought in this example is What is the average parasitic current draw over the 40 day period Answer Parasitic current Curent when onx nutes on Current when ofr x off minutes 40 days minutes in 40 days First 6 weeks is equal to 42 days so this current level is not used in estimating the average parasitic current There are five 1 minute intervals 1 5 above when the ECU is powered the 40 day interval and therefore 57 600 5 minutes when it isn t 40 days 57 600 minutes Thus the average parasitic current is Parasitic current 350mAx 576 2 0 230 00 57600 Procedure The current is measured in the various states of awake asleep No long Monitoring term monitoring is to occur GENERAL MOTORS CORPORATION EDSON 2008 196 197 Operating test shall be performed under operating type 2 1 under operating type 2 2 as shown in figures 23 and 24 Monitor the current in all of the DUT supply lines and choose an appropriate current measuring device The current measuring device must have sampling frequency that is ten times higher than the smallest current peak the module crea
396. wing logic diagram for short circuit testing which may include the intermittent continuous and through ground connection test Devices without Smart Protection Circuits should be evaluated using the Load Circuit Over current Test or the ISO 8820 test to evaluate the ability of the components and circuit traces to withstand the excess current flow while waiting for the fuse to open The through ground connection test may also be required for devices that are only protected by the fuse GENERAL MOTORS CORPORATION EDSON 2008 following graphic will help explain the logic of which tests are to be run Logic For Short Circuit Testing Self Protecting Smart Fuse Protected Not Device Smart Device Intermittent Short Circuit Test Bussed I Electrical Center Continuous Short Circuit Test v Load Circuit Over Current Test As Described In GMW3172 ISO 8820 Test Through Ground On Circuit Board Ground Inter Connect On Circuit Board Short To B Test INTERMITTENT SHORT CIRCUIT Purpose To determine if the E E device is able to meet specified requirements when subjected to short circuit conditions This test is only required for outputs that are specified to be short circuit protected by means of electronic current limiting Locations of Applicability locations Procedure Monitoring Proper functi
397. would have reason to believe that the bracket may break during the test 5 016 686 1 990 224 317 995 Miners Index Percent ES 3 000 000 10 6 GENERAL MOTORS CORPORATION EDSON 2008 320 We compare this percentage value against the following criteria A value less than 33 will meet the reliability requirements of GMW3172 A value less than 70 will produce an acceptable product with some degree of reliability but less than that required by GMW3172 A value close to but less than 100 means that the bracket will not break on the test if you are very very lucky so I have just one question for you are you feeling lucky today Life Life vs Stress 1 00E 8 Infinite Life 1 00E 7 211 3 000 000 1 00 6 High Cycle Fatigue 1 00E 5 10000 1000 Low Cycle Fatigue 100 A 6 6 6 6 6 77 5 100 Stress Ksi Because finally he said Most people still stop at the Z This is really great stuff But not HE And guess the old alphabet ISN T enough Dr Seuss On Beyond Zebra NOW the letters he uses are something to see 3
398. x60 x24 lt 27 1 1 990 224 cycles reversals n BS cycles x 60 X 60 min 24 x 4 33 317 995 cycles reversals Applying each of the three forces 1 Sigma Force 2 Sigma Force and 3 Sigma Force in our FEA model provides the following three stress level within the bracket StresSlmax 28 Ksi StreSS2max 37 Ksi StreSS3max 45 Ksi We know from our calculations of and n3 that 5 will occur for 5 016 686 cycles StresS2max Will occur for 1 990 224 cycles Stress3max Will occur for 317 995 cycles We turn to our S N curve for the material that the bracket is made from and identify the number of cycles to failure at each of the three stress levels An example S N curve for steel is shown on the following page The cycles to failure values are obtained by finding the stress level on the X axis and moving up the Y axis until the S N Line is encountered The intersection of the stress level and the S N line provides the life expectancy at that stress level read life from the Y axis This process must be carried out for each of the three stresses The three life values will give us the big values Ni that are to be used in our Miner s Index Calculation Performing this calculation for our example shows that the total sum of the damage from this test will only remove 10 6 of the total life from the bracket If the Miner s Index Percentage approached 10096 then we
399. y 5 5 162 High Altitude Shipping Pressure Effect 1 8 222 0 0 0000000000000000 00 163 anap LOCKT ener An TES 164 A TEE A SE EE EA Re ee AE E een ere hee 165 E a O NE EOE AEN A E E EEE AN E NE E E ET 165 TEMPERSTURD ANALI 166 High Altitude Operation Overheating ANALYSIS aai 166 a CARA 1 E E E E E E A ere E E Raman D E 168 ANALYTICAL RESULTS REVIEW aia nan 169 DEVELOPMENT AND EVALUATION 5 170 FUNCTIONAL AND DIMENSIONAL TESTS IN DEVELOPMENT 2 2 222222 000 170 Functional Checks And Continuous Monitoring 171 IBI OU RTT A 178 VEST Device ASE CIO and 173 ELECTRICAL LESTS IN DEVELOPMENT cuero in dinosaurios 174 MS quM URN MUNI 174 E E A E A E EEE A E E E 179 Ps 176 SU OQEBI UMP Um 177 eu s DTI ET ee ar 178 COm nons S NOTT
400. y from the battery while the vehicle is in an ignition off state must be known and approved Parasitic current is defined as the current drawn by electrical devices when the vehicle ignition switch is in the OFF position and electrical accessories turned OFF This test defines the maximum acceptable average parasitic current of an electronic component GENERAL MOTORS CORPORATION EDSON 2008 194 The following example should provide Locations of Applicability some guidance in how to apply the procedural explanations provided in All devices that will draw some current the procedure section that follows when the engine is turned off Simple Example Average Parasitic Current Calculation This test is only to define the parasitic loss from expected operations Other devices may unknowingly wakeup this device but that fact is not to be included in this test process The ignition is turned off and our example ECU becomes off awake for two minutes and then hibernates in off asleep state until the ignition is reactivated Immediately after being placed in the OFF power mode the ECU is off awake for 2 minutes e Following the above two minutes in the off awake state the ECU becomes off asleep until the ignition is turned on 40 days later Figure 24 Simple Parasitic Current Measurement Parasitic Current Simple Example Graphic Note Values shown are for this example You must measure your own values Off
401. you intersect the one failure line Redraw a new line between this intersection point and the prior confidence value on the right scale to obtain the reliability value on the left scale A full scale version of this nomograph appears at the end of this section Non Parametric Success Run Testing The Reverend Thomas Bayes an English minister of the eighteenth century develops a theorem of Statistical inference relating reliability confidence and sample size This was later modified by Laplace and is commonly referred to today as Bayes formula Success Run Theorem formula is unaffected by the different shapes that life data may take and is seen most often in the following form And can be rewritten as y In 1 C In R R Reliability C Confidence N Sample Size MULTIPLE LIFE TESTING Testing beyond the specified number of cycles or hours in one life REP in order to make up for a reduction in the number of samples being tested This technique is usually paired with a success run test strategy where the original sample size is determined from the success run equation A reduction in sample size is chosen based upon practical needs The original sample size and the arbitrarily chosen reduced sample size are used in determining how many multiples of a life are needed to compensate for the reduced sample size Multiple Life Testing uses the Weibayes equation to establish the

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