troubleshooting molding problems
Contents
1. E 21 22 Mold A 23 Molded Poly 24 i aes 25 Paint Sags coisa sole cose 2 ee eee 26 ERNA 27 1 lt A cc o a Gcco0c6E0000000000050600 E 9 28 RESIN E eR eR cscs 29 Rib Pin and Boss Readout 30 Se MARI A scene AE lt a 31 Sand Through RS ENE T sc cee 32 Sander Scratches 22 enine 33 cccccccecseesessceteecesssessesrseseeesesseseee Meson sea ae MAAE SAE 34 Separation Phasing os s se a ing 35 A o sss A E R 36 Sink 2 S E eaa Ree E ec ET 37 38 Streaking Ds ken Maenner 7 39 Surface WAVINESS csnciscivesssentdcncsadiensscadiacacseddeedediees teens 00 0050000000000000 A i 40 66003 Me2. Material Process e Rough handling Improperly designed secondary fixtures not padded in all necessary areas e Mold defects on edges or flash stuck to shear edge e Shipping racks lack necessary padding No use of in process racks parts are stacked on each other Square edge on part at mating surface with adjacent parts Tooling Corrective Action Material Process Investigate potential source for gouges in process and correct e Train workers in proper handling techniques e Design secondary fixtures properly and coat them with soft materials to absorb shocks e Preventative maintenance on molds and fixtures e Periodically clean flash on shear edges e Improve shipping rack repair procedures e Utilize transfer lines and other hands off processing techniques e Repair using approved repair procedure Tooling 407 South 7 Street Noblesville Indiana 46060 317 773 1766 www idicomposites com Page 19 44 Composites iD International THERMOSET MOLDING COMPOUNDS Hanging Fibers Hanging fibers are glass fibers that are left hanging from the part after a deflashing hold piercing or drilling operation These fibers cause dirt to be carried into the paint shop Probable Cause Material Process Dull or improperly fit secondary tooling bits mash offs punches etc Improper sanding to remove fibers Tooling e Dull deflashing tool Corrective Action Material
3. Decrease molding pressure e Decrease molding temperature Tooling 407 South 7 Street Noblesville Indiana 46060 317 773 1766 www idicomposites com 35 44 Composites iD international THERMOSET MOLDING COMPOUNDS Scumming Dulling or streaks in the part generally transfers a similar pattern on the tool surface Probable Cause Material e Incompatible resin additives Process Internal mold release not functioning at the mold temperature Tooling Corrective Action Material e Use greater viscosity material e Select different shrink additives and or levels Process Increase mold temperature Increase material flow distance e Shorten tool loading time Tooling 407 South 7 Street Noblesville Indiana 46060 317 773 1766 www idicomposites com Page 36 44 Composites iD international THERMOSET MOLDING COMPOUNDS Sink Marks A sink is a depression on the part surface that will normally occur over ribs or bosses It is possible to get a sink on the edge of a flanged part Sinks can range in depth from 0 0004 to several thousands of an inch anywhere along a rib or boss Probable Cause Material e Poor glass orientation e Excess shrinkage of the SMC over a thick section Process Inadequate molding pressure e Temperature variations due to variable thickness Tooling Improper rib design Corrective Action Material
4. Hot spots from adhesive exothermic reaction due to non uniform adhesive thickness e Bond gap thick above 1 5 mm e Bond gap thin below 0 5 mm e Outer panel thin less than 2 0 mm Inner thickness above maximum Tooling Corrective Action Material Process Increase the thickness of the bonding area of the appearance panel or select more flexible adhesive e Match the thermal expansion coefficients between the substrate and the adhesive as much as possible e Select an adhesive with minimum polymerization shrinkage e Obtain matched outer inner panels through better tooling Eliminate bond line standoffs e Use closed loop feedback temperature control system for tighter temperature variation tolerance of the fixture e Minimize and control clamp pressure e Mold warp free parts do not use adhesive bond fixture to straighten parts e Check adhesive thickness to specification e Check outer thickness to specification e Check inner thickness to specification Tooling 407 South 7 Street Noblesville Indiana 46060 317 773 1766 www idicomposites com Page 5 44 Chip Composites iD international THERMOSET MOLDING COMPOUNDS A chip is damage to the surface of the part that results in small less than 2 inch missing pieces A chip usually occurs near the edge and since it is nonstructural it usually is repairable Probable Cause Material e Resin rich edge Proce
5. Flow parallel to shears Tooling Improperly fit or worn shear edges Corrective Action Material Process e Use sandpapers file or automatic router to deflash instead of a knife e Closer inspection of punched and drilled holes e Use high technology process such as router water jet laser or ultrasonics to perform deflash punch and drill operations e Verify correct load pattern weight e Verify appropriate temperature differential between core and cavity e Verify appropriate molding temperature e Slow ejector speed e Adjust charge to minimize flow parallel to shears Tooling e Maintain proper shear edge on molds to minimize flash 407 South 7 Street Noblesville Indiana 46060 317 773 1766 www idicomposites com Page 14 44 Composites iD International THERMOSET MOLDING COMPOUNDS Finger Tracks Finger tracks are shallow groves in the surface that show up after prime or top coat These grooves are usually the width of a finger Probable Cause Material Process e Sanding the surface without a block or backup pad The pressure directly under the fingers removes more material than between the fingers and leaves tracks that show up on the painted surface It is generally accepted that the eye can detect surface depressions of 0 0004 inches or greater over a one inch span Tooling Corrective Action Material Process e Always use block or pad when sandi
6. Process Tooling e Slow strip speed e Clean mold surface run break in material e Add external mold release Increase cycle time e Increase mold temperature e Evaluate mold for undercuts and remove where necessary e Check chrome plating wear e Polish tool surface Pyramid charge in the center of the tool 407 South 7 Street Noblesville Indiana 46060 317 773 1766 www idicomposites com Page 38 44 Composites iD International THERMOSET MOLDING COMPOUNDS Streaking Abrasion Dark areas directional in line of flow found in pigmented parts and is generally located over fiberglass strands Probable Cause Material Process Tooling e Tool abrasion or scuffing Corrective Action Material e Check raw material Use greater viscosity material Select different shrink additive or level Process e Relocate charge pattern Tooling e Polish or buff out tool surface e Chrome plate tool surface 407 South 7 Street Noblesville Indiana 46060 317 773 1766 www idicomposites com Page 39 44 Composites iD international THERMOSET MOLDING COMPOUNDS Surface Waviness Short term waviness has wave lengths for to one inch long Long term waviness has wave lengths from one to five inches Waviness causes distortion of straight lines on the Class A surface and is most readily observed on a painted part Probable Cause M
7. Process e Closer inspection of pierced and drilled holes e Use high technology process such as router drill bit design water jet laser or ultrasonics to perform deflash punch and drill operations Tooling Proper maintenance program need for molds pierce dies and secondary tools 407 South 7 Street Noblesville Indiana 46060 317 773 1766 www idicomposites com 20 44 Knit Lines IDI Composites international THERMOSET MOLDING COMPOUNDS meeting Knit line is a term for the molding condition which relates to oriented fiber patterns in the molded part The knit line usually occurs at the edges or corners of the part furthest from the charge placement position It is an extremely weak area in the molded part resulting from two flow fronts Probable Cause Material Process Flow fronts from different charge pattern pieces e Too far of a distance for the SMC to flow e Charge pattern position e Incorrect rate of tonnage build Spiral flow of SMC to high low Mold temperatures too high Tooling e Mold design deep vertical walls etc Corrective Action Material Process e Appropriate load placement Proper press closure e Proper load pattern dimensions e Consistent tonnage build e Check oil level in press e Place charge directly over critical or knit line area if possible Decrease closure speed reduce amount of orientation Eliminate separate charges if pos
8. not padded in all necessary areas e Mold defects on edges or flash stuck to shear edge e Shipping racks lack necessary padding No use of in process racks parts are stacked on each other Square edge of part a mating surface with adjacent parts Tooling Corrective Action Material Process Tooling e Train workers in proper handling techniques e Design secondary fixtures properly and coat them with soft materials to absorb shocks e Design secondary fixtures properly and coat them with soft materials to absorb shocks e Preventative maintenance on molds and fixtures e Periodically clean flash on shear edge Improve shipping procedure and monitor part quality e Improve shipping rack repair procedures e Utilize transfer lines and other hands off processing techniques e Repair using approved repair procedure 407 South 7 Street Noblesville Indiana 46060 317 773 1766 www idicomposites com Page 34 44 Separation Phasing IDI Composites international THERMOSET MOLDING COMPOUNDS An area of high thermoplastic content resulting in non uniformity of color Probable Cause Material e Separation of the thermoplastic resin from polyester Process Tooling Corrective Action Material e Increase molding viscosity e Select different shrink additives and or levels Process e Shorten die loading time Increase material flow distance
9. e Select different shrink additives and or levels Process Flow material from a thick section to thin section so as to create surge flow patterns in localized areas the surge flow orients glass fibers perpendicular to adjacent areas which shows up as a sink e Cross sectioning the wall section may be necessary to prove a thin to thick flow condition e Control aspect ratio of rib and boss depth to thickness ratio rib should not be more than 0 075 thickness of attached wall e Place ribs and bosses behind design lines Mold off stops If sink is over a boss reduce mass by having a long cored hole Tooling e Modify tooling 407 South 7 Street Noblesville Indiana 46060 317 773 1766 www idicomposites com Page 37 44 Sticking IDI Composites International THERMOSET MOLDING COMPOUNDS Sticking occurs when the part adheres to the cavity or core and is not easily released or results ina crack upon removal Probable Cause Material Process e Release problem with the SMC e SMC shrinkage control is incorrect e Core is too rough e Charge weight is excessive e Undercuts on cavity or core e Part is under cured e Temperature spread on dies too close e Press strip is too fast Contaminated mold surface oils dirt etc Tooling Corrective Action Mold surface is corroded Material e Check for SMC release e Check SMC shrinkage data
10. insufficient protection e Stuck parts that require scraping off the mold Improper tools used to clean the mold e Thickness variation flowing thin to thick causing tool wear Hard metal object molded into part causing mold damage Corrective Action Material Proper QC of SMC materials will reduce the sticking of parts Process Tooling e Repair molds as required e Regular maintenance program for molds e Make sure all cutting utensils are made from soft materials that will not damage the mold surface Make sure all employees use only copper brass wood or plastic tools to scrape the mold surface e Wire down all loose items on the cutting table and loading unloading equipment e Protect mold surface in transport and storage Automation should be constructed from aluminum or other soft materials 407 South 7 Street Noblesville Indiana 46060 317 773 1766 www idicomposites com 23 44 Composites iD International THERMOSET MOLDING COMPOUNDS Molded Poly Irregular shaped small depressions on the surface of a part shaped like carrier film chips but recessed into the substrate These depressions are normally the colour of the film Probable Cause Material Process e Pieces of carrier film that are molded into the SMC part Tooling Corrective Action Material Process e Make sure that all carrier film is removed from the charge espec
11. Composites International THERMOSET MOLDING COMPOUNDS TROUBLESHOOTING MOLDING PROBLEMS Molding Guide for BMC amp SMC IDI Composites International May 2013 407 5 7 Street Noblesville Indiana 46060 317 773 1766 Fax 317 773 3877 www idicomposites com Composites iD International THERMOSET MOLDING COMPOUNDS Table of Contents Faille 4 BONG 5 GIP 6 CONMTAMINALION 7 Crazing Surface TA 8 ea needa ean 9 10 DUI SUinf aCe 11 Ejector adsduiedheas a a Ea aaaea ee 12 Fiber Pull E E E E A 13 Fiber Tea E E A T E A E AA 14 Finger TACKS E E N E E 15 E E A E E A o FEPEEEEE 16 Flow Marks E E E E E 17 ca aaia A a 18 oO ocoonoooiaononita 19 Hanging 05 65 77 00 0 Ee RE sn ve 20 Knit
12. Tooling 407 South 7 Street Noblesville Indiana 46060 317 773 1766 www idicomposites com Page 26 44 Porosity IDI Composites International THERMOSET MOLDING COMPOUNDS Porosity is an observable or unobservable condition in any part It consists of a cluster of holes that usually occurs when trapped air escapes during the molding process This cluster usually covers an area no larger than a quarter but can be larger and can occur as a single hole Unfilled porosity creates a crater type condition on a top coated part Probable Cause Material e Excess styrene loss Process Insufficient flow of the SMC too large small a charge pattern e Pre gel e Flash on shear edge prevents adequate venting of gasses e Insufficient pressure on material during molding Improper press closure speed Mold temperature too high e Vacuum too low improper vacuum cycle e Undercure e Low charge weight e Adding small SMC pieces to charge pattern many plies e Molding on stops e Moisture contamination Tooling Corrective Action Material e Evaluate viscosity level e Verify material is not dried out Process e Verify vacuum amount and timing e Verify load pattern location size thickness e Verify appropriate press closure speeds e Verify appropriate temperatures e Verify molding off stops e Make sure mold shears are clean Increase material flow distanc
13. aintain a rinse additive after parts washing Tooling 407 South 7 Street Noblesville Indiana 46060 317 773 1766 www idicomposites com 43 44 Composites iD international White Spots A general light or whitened area on a pigmented surface that occurs as a result of thermoplastic separation The problem is associated with pitting occurring in the white spotted area Probable Cause Material e Low viscosity builds of SMC through maturation e Thermoplastic incompatibility with SMC formulations e Flow restrictions Process Tooling Corrective Action Material e Verify day 1 viscosity e Record occurrence and roll yardage when problem occurs e Record material rates and lot number when problem occurs Verify spiral flow of material Process e Verify load pattern is correct according to engineering specification e Reduce die coverage to allow for increased flow Tooling 407 South 7 Street Noblesville Indiana 46060 317 773 1766 www idicomposites com Page 44 44
14. aterial Process e Improper spiral flow of SMC sheet when molded e Inconsistent force on the material during molding e Parts molded with improper pressure e Charge pattern cut or placed improperly Flow interrupters mash offs core pins part geometry in mold e Partial charge e Improper bonding temperature Undercure which can cause bond readout causing waviness Tooling Corrective Action Material Process e Monitor spiral flow for appropriate values e Use proper pressure to mold material e Remove flow interrupters from mold e Monitor viscosity of paste Monitor and control mold temperatures to specs e Refer to design guide for allowable thick to thin transition e Verify closure speeds load pattern location size and leveling e Verify molding off stops e Monitor viscosity of paste Tooling 407 South 7 Street Noblesville Indiana 46060 317 773 1766 www idicomposites com Page 40 44 Composites iD international THERMOSET MOLDING COMPOUNDS Undercure Undercure is an incomplete cure or bake cycle of the SMC in the mold The part is often extremely smoky very dull and can exhibit blown bosses or ribs This part is scrapped Probable Cause Material e Unreactive resin Incorrect cure chemistry Process e Low temperatures and or short cycle time e Loss of tonnage Tooling Corrective Action Material Check SMC for cure time e Check resi
15. cracks on the cavity side surface of the molded part These are often found on the opposite side of the part above an ejector pin A crack located on the surface of the laminate that does not extend completely through the substrate Material e Resin Reactivity Process Tooling Corrective Action e The part is sticking to the core e The part is under cured e Cure time is too low Mold temperature is too low e Insufficient release agent e The ejector pin is placed in a poor location too few fins or too small a diameter e Ejection system is too fast e Blocked air to popper passage partial Improperly sized air supply line to air popper Ejection system leading air popper blow off e Excess flash around ejection pin Undercuts along shear acting as hangers Material Use less reactive catalyst Process e Check temperature and cure times e Place ejector pins in areas least sensitive such as below ribs or bosses increase diameter or number of pins Add vented ejector pins e Verify correct load pattern weight Add external mold release mold one part then discard that part e Clean shear edges Tooling e Slow ejection system e Check mold for undercuts e Alleviate stresses holding the part too tight to the core undercuts etc e Proper sequencing of air popper system Inspect mold for biased ejection install flow control or dividers e If ejectors are on an
16. crease closure speed e Ensure charge weights are balanced e Decrease material flow distance e Check oil level in press Vent ejector pins and or add vented ejector pins e Shorten tool load time Tooling e Blend core half to reduce thin to thick flow restrictions in area of non fill 407 South 7 Street Noblesville Indiana 46060 317 773 1766 www idicomposites com Page 25 44 Composites iD international THERMOSET MOLDING COMPOUNDS Paint Sags A sag is excess paint on a part that shows itself as a hump or ripple that distorts the surface Probable Cause Material Process Oven temperature too low e Viscosity of paint too low too much solvent e Film build too thick e Spray gun too close to part being painted Inconsistent sanding of parts to be reworked causing sags when painting with electrostatics Tooling Corrective Action Material Process QC paint viscosity on each shift e Monitor and control ultimate over temperature and heat up rate Do not allow painters to get ahead or behind job sequence e Instruct painters on proper spray techniques e Preventative maintenance of spray equipment Implement automatic paint spraying equipment e Verify appropriate air pressure e Verify appropriate paint pressure e Increase distance between part gun e Use more coats of paint to get desired film build e Thoroughly scuff sand reworks prior to paint
17. e e Minimize number of plies in charge e Check charge weight e Check molding pressure e Clean mold stops Tooling e Change part wall thickness 407 South 7 Street Noblesville Indiana 46060 317 773 1766 www idicomposites com Page 27 44 Pre Gel IDI Composites International THERMOSET MOLDING COMPOUNDS Pre gel causes localized areas of dull rough porosity usually with discoloration Probable Cause Material e Too reactive resin e Too reactive catalyst Process e Slow closure rate Tooling Corrective Action Material e Check resin reactivity e Use less reactive catalyst Process e Shorten tool loading time Increase press closure rates e Decrease mold temperature Tooling 407 South 7 Street Noblesville Indiana 46060 317 773 1766 www idicomposites com Page 28 44 Resin Rich IDI Composites international THERMOSET MOLDING COMPOUNDS An area in the part where fiberglass strands content is low Probable Cause Material e Resin is not carrying fiberglass strands Process Tooling Corrective Action Material e Increase material molding viscosity Process e Relocate charge pattern e Decrease material flow distance Slow pressure closure rate Tooling 407 South 7 Street Noblesville Indiana 46060 317 773 1766 www idicomposites com 29 44 Composites iD int
18. ernational THERMOSET MOLDING COMPOUNDS Rib Pin and Boss Readout A surface depression located over ribs bosses ejector pins or thick sections of the part that appear as a lighter color resulting in read through Probable Cause Material Process e Lack of material flow Lack of cavity core temperature differential Lack of a tonnage bump decrease molding pressure after 30 seconds into cycle Tooling Corrective Action Material Process Increase material flow distance do not load over a boss Increase mold temperature differential the hotter appearance side will gel slightly faster and will reduce the amount of sink Reduce tonnage after mold fill high tonnage held through the cure cycle increases sink Reduce tonnage by 25 to 30 after 30 seconds Tooling 407 South 7 Street Noblesville Indiana 46060 317 773 1766 www idicomposites com Page 30 44 Composites iD International THERMOSET MOLDING COMPOUNDS Ripple Severe short term waves in the SMC almost always on the edge of a part or vertical walls Probable Cause Material e Improper viscosity e Material too old and will not flow properly e Higher paste shrinkage Improperly maturated SMC e Extremely high flowing SMC Process e Inconsistent force on the material during molding e Charge pattern placed or cut improperly e Temperature of mold too high or dropped temperature zone of
19. et Noblesville Indiana 46060 317 773 1766 www idicomposites com Page 16 44 Flow Marks IDI Composites international THERMOSET MOLDING COMPOUNDS Flow marks is the visual orientation of fiberglass strands on the part surface Probable Cause Material Process Flow condition Tooling e Tool design Corrective Action Material e Evaluate molding viscosity effect Select different shrink additives or levels Process e Decrease material flow distance e Relocate charge pattern Increase press closure rate Tooling e Change part wall thickness 407 South 7 Street Noblesville Indiana 46060 317 773 1766 www idicomposites com Page 17 44 Composites iD International THERMOSET MOLDING COMPOUNDS Fractures A Fracture is a structural failure in a part which extends complete through the substrate Probable Cause Material Insufficient glass reinforcement Sticking or wedging of part in mold Process e Mechanical hang up from flow related knit lines e Rough handling Poor material flow pattern around mash offs etc e Charge pattern change by adding small pieces to produce proper weight e In process racks not used or poor quality secondary fixtures e Press opens askew e Poor part design if every part is cracked Improper combination of drill speed and feed rate e Shipping damage e Heavier shear on one edge Dull drill bit o
20. gled surface add skid grooves to top of ejector pin 407 South 7 Street Noblesville Indiana 46060 317 773 1766 www idicomposites com Page 12 44 Composites iD International THERMOSET MOLDING COMPOUNDS Fiber Pull Fiber Pull is a depression left by removing or loosening of fiberglass strands located near the surface of the laminate Probable Cause Material Sticking Process e Flash buildup on the by pass Tooling Worn by pass Corrective Action Material Process e Add external mold release and clean by pass Vary mold temperature differential normally narrow the difference e Decrease by pass opening e Correct ejector action are all ejector pins working e Slow ejector speed Tooling 407 South 7 Street Noblesville Indiana 46060 317 773 1766 www idicomposites com Page 13 44 Composites iD International THERMOSET MOLDING COMPOUNDS Fiber Tear Fiber tear is a surface defect caused by fibers tearing away part of the surface resin These defects always occur near the shear edge of a part Probable Cause Material Process Improper deflashing of the part e Ejector speed too fast e Charge weight too high Mold temperature differential incorrect Molding pressure too high e Molding viscosity too low e Shear edge temperature variance too liberal causing excess flash leakage e Molding press strip speed too fast
21. hesive or surface to be bonded e Out of spec adhesive e Excessive internal or external mold release in on the SMC e Shift between inner and outer panels during curing of the adhesive Incompatible substrate and bond material Introduction of air into dispense system causing gaps ratio variations Improper cure cycle Improper heating during bond cycle Tooling Corrective Action Material Process Improve QC of adhesive material Fully cure adhesive before pressure or clamping is removed e Properly prepare surfaces be bonded e Ensure that periodic check of the mix ratio is performed e Control temperature of adhesive DO no use external mold release on bond areas Tooling 407 South 7 Street Noblesville Indiana 46060 317 773 1766 www idicomposites com Page 4 44 Composites iD International THERMOSET MOLDING COMPOUNDS Bond Readout Bond readout is a surface distortion similar to a hump or sink that occurs over a bond line Probable Cause Material Process e Mismatch of compliance between outer panel inner panel and adhesive e Incompatible thermal expansion coefficients between the SMC and the adhesive e Excessive shrinkage of the adhesive during the fixturing and curing cycles e Excessive fixturing pressure induced due to part mismatch of the outer inner panels and the bond line standoffs e Excessive fixturing temperature due to non uniform heating
22. ially when automatic film stripping is not used e Proper repair procedure required e Frequent changing of blades to ensure clean cuts e Check for proper slitter cutter alignment to shear guide Improper alignment will cause a small strip to adhere to the edge of the SMC unnoticed Tooling 407 South 7 Street Noblesville Indiana 46060 317 773 1766 www idicomposites com 24 44 Composites iD international THERMOSET MOLDING COMPOUNDS Non Fill A non fill is a severe void the laminate It is an incomplete part that must be scrapped Probable Cause Material Process e Tonnage too low Mold temperatures too high Not enough SMC charge weight e Molding on stops Press closure too slow tonnage build rate too slow Mold temperatures of cavity core are too close no flash e Flash debris on the mold shears stops e SMC charge sits on mold too long before closure e SMC charge has to flow too far Tooling e Tool or platen deflects Corrective Action Material Decrease molding viscosity e Use less reactive catalyst Process Verify parameters to control plan process sheet tonnage load pattern load placement temperature closure speeds e Check SMC spiral flow e Verify molding off stops e Clean mold shears stops e Check for deflection e Monitor SMC viscosity build Verify weight scales are correct e Increase molding pressure In
23. ibers etc from workers Improper paint shop cleanliness De ionized rinse out of spec Tooling Corrective Action Material Process e Installation of appropriate power washer e Automate paint operations Proper maintenance of paint equipment and paint booth e Remove and clean overspray on the paint racks per agreed upon schedule e Analyze dirt particles to accurately determine source e Clean overhead conveyor e Improve paint shop cleanliness procedures Tooling 407 South 7 Street Noblesville Indiana 46060 317 773 1766 www idicomposites com Page 10 44 Dull Surface IDI Composites international THERMOSET MOLDING COMPOUNDS Loss of gloss on overall part surface Probable Cause Corrective Action Material e High shrinkage Process e Under cure e Loss of pressure Tooling Unacceptable tool surface Material e Check for catalyst level e Check resin reactivity e Select different shrink additives or levels Process Increase mold temperature Increase cure cycle Increase molding pressure e Maintain constant material pressure in press Tooling e Polish and buff tool surface Chrome plate tool surface 407 South 7 Street Noblesville Indiana 46060 317 773 1766 www idicomposites com Page 11 44 Composites iD international THERMOSET MOLDING COMPOUNDS Ejector Cracks Probable Cause Ejector cracks are small visible surface
24. mbly review bonding process e Verify cure time versus tool temperature capability of maintaining correct temperature through consecutive moldings e Decrease material flow distance Increase cure time or temperature e Vary mold temperature differential e Increase charge pattern e Verify mold temperatures Tooling Proper mold design to ensure that the part does not stick to core or cavity e Work with design engineers early in program so that mold is constructed using expansion factors of the newer technology materials 407 South 7 Street Noblesville Indiana 46060 317 773 1766 www idicomposites com Page 42 44 Composites iD International THERMOSET MOLDING COMPOUNDS Water Spots Circular spots on the painted surface usually in groups These spots are usually depressions with a raised ring around the edge Water spots can cause paint failure of top coats Probable Cause Material Process e Failure to fully dry the part after a wash operation e Failure to sue a DI water rinse after wash e Failure to clean and filter DI water to meet specifications e Part designs which trap water in pockets e Failure to use a rinse additive which ensures a water break free surface Tooling Corrective Action Material Process Dry parts thoroughly after all wash operations e Design drain holes into parts when necessary to prevent the accumulation of water during the wash cycle e QC rinse water to specs e Use and m
25. mold Improper closure speed e Abrupt thick to thin flow condition e Reflow of material due to non parallel closure leveling Tooling Mold not centered to press platen Flow turbulence resulting from tool design Corrective Action Material e Investigate viscosity of paste e Verify SMC is within appropriate spiral flow Investigate past shrinkage Process e Increase tonnage e Decrease material flow distance e Verify charge weight Verify molding off stops e Monitor and control mold temperatures to specs Tooling e May need to offset mold e Modify tooling 407 South 7 Street Noblesville Indiana 46060 317 773 1766 www idicomposites com Page 31 44 Composites iD international THERMOSET MOLDING COMPOUNDS Sand Through A sand through is a break through the primer surface resulting from a sanding operation Probable Cause Material Process Localized sanding that is deeper and more severe than is necessary finger sanding e Tipping power sander to cut deeper one area to remove dirt or other localized defects e Sanding with too course a sandpaper Tooling Corrective Action Material Process e Always block sand defects e Repair mold when mold marks appear to minimize the amount of sanding e Goal is to avoid using sandpaper Eliminate use of power sanders e Use only 400 grit or finer sandpaper Tooling 407 South 7 Stree
26. n reactivity Process e Check mold cold spots or bad stream lines and regulators Verify cure times e Verify tonnage via parameter sheet Tooling 407 South 7 Street Noblesville Indiana 46060 317 773 1766 www idicomposites com Page 41 44 Composites iD International THERMOSET MOLDING COMPOUNDS Warpage Dimensional Error Dimensional error is the failure of the part to fit the checking fixture or to meet print tolerances due to Warpage shrink expansion or tooling error Probable Cause Material e Out of spec material Process e Uneven cure e Excessive stress on the part when unloading or bonding e Not allowing the part to cool on fixture long enough e Variable charge pattern or placement Improper expansion factor in tool for approved material Improper thermal expansion material molded in approved mold Improperly designed paint fixture Degree of cure bond line Tooling Tool temperatures not within spec Corrective Action Material Verify SMC for proper shrinkage Process e Use heat management design of mold to permit consistent curing of part Proper placement of ejector pins reduces demolding stress e Evaluate process for sufficient cooling time e Control charge pattern by area not weight When possible use laser light or automation to permit consistent charge placement e Design paint fixtures to properly support part during baking If bonded asse
27. ng the surface e Develop sanding and feathering techniques that blend surface changes over large areas Use 400 grit or finer sandpaper Tooling 407 South 7 Street Noblesville Indiana 46060 317 773 1766 www idicomposites com Page 15 44 Composites iD international THERMOSET MOLDING COMPOUNDS Fish Eye A fish eye is a circular or elliptical depression in the primer There is not any penetration into the substrate Fish eyes are usually caused by some type of surface contamination Probable Cause Material Process Oil grease or silicone contamination in paint system air feed paint conveyor line or in the paint itself e Rags containing oil or oil byproducts e Excess mold release at source e Insufficient cleaning of the part e Overspray of primer e Mismatch of solvent with paint or prime system Ensure parts not being sprayed or dripped on at press by hydraulic oils if so with 50 IPA and 50 DI water Tooling Corrective Action Material Process Do not use silicone containing hand creams or lubricants during handling at press side or bonding e Properly installed power washer for all SMC parts Proper maintenance of equipment filters etc e Ensure proper use of oils and lubricants the paint shop Proper QC procedures on all paint materials e Fish eye reducing additives to paint are available Tooling 407 South 7 Stre
28. or pin crazing e Increase differential temperature between core and cavity Tooling Design secondary fixtures so they do not induce stress the part and coat them with soft materials to absorb shock e Polish shear edges of cavity eliminate back draft or undercuts e Ensure smooth transition from thick to thin sections 407 South 7 Street Noblesville Indiana 46060 317 773 1766 www idicomposites com Page 8 44 Composites iD international THERMOSET MOLDING COMPOUNDS Dieseling Dieseling is a burnt spot on the laminate often accompanied by non fills Probable Cause Material Process e Air entrapped in the tool which burns Tooling Corrective Action Material Process Increase material flow distance Slow press closure e Vary mold temperature differential Increase shear opening assumes dieseling occurs near the shear edge Add vented ejector pins Tooling 407 South 7 Street Noblesville Indiana 46060 317 773 1766 www idicomposites com Page 9 44 Composites iD international THERMOSET MOLDING COMPOUNDS Dirt Dirt is a particulate contaminate under or in any paint film that shows up as a raised bump of the cured paint film Probable Cause Material Process e Dirt on parts as received Dirt created by repairing SMC defects e Dirt on the paint rack that is not washed off e Dirt hair f
29. r worn out sleeve Undercut at parting lines or undercut in the mold e Shears too tight e Cure time too short e Parallelism of ejectors Tooling Improperly designed secondary fixtures or tooling Corrective Action Material Control SMC sheet weight to allow use of automatic cutting of charge patterns Use QC on SMC glass content e Check SMC flow Process e Train workers in proper handling techniques Reduce material flow distance reduce the flow front Design charge pattern to minimize improper flow behavior Do not use make up pieces in charge patterns e Properly support part in shipping containers e Evaluate proper paint rack design e Check shears e Change drill bit or sleeve e Eliminate any undercuts in the mold e Increase cure time e Slow ejector speed e Vary mold temperature differential Add vented ejector pins e Relocate charge Tooling e Design secondary fixtures so that they not induce stress the part e Draw polish shear edges in the cavity Use parallelism control on the press e Change part wall thickness 407 South 7 Street Noblesville Indiana 46060 317 773 1766 www idicomposites com Page 18 44 Gouge Composites iD international THERMOSET MOLDING COMPOUNDS A gouge is a long deep depression in the surface severe enough to require a repair procedure Gouges can be several thousands of an inch deep Probable Cause
30. saad Sanda bunededddeeetsessans 41 Warpage Dimensional Error 42 Water aa a aa ia Memes oe oc aaa aa a eo REER 43 White Spots iare enai aean eaei 44 407 South 7 Street Noblesville Indiana 46060 317 773 1766 www idicomposites com Page 2 44 Blisters Composites iD international THERMOSET MOLDING COMPOUNDS A blister is a delamination that produces a bulge on the surface of the part This bulge is usually regular in shape and can range in size from 1 8 to 10 inches A blister is caused by the presence of gases under pressure within the substrate forcing the skin away from the glass Can be seen on painted or unpainted parts Probable Cause Material Insufficient glass wet out with resin dry glass e Foreign objects contamination film flash etc in or on the charge Wrinkles pockets in discontinuous surface of SMC charge pattern Process e Adding small SMC pieces to charge pattern which trap air Insufficient pressure on SMC during cure cycle Oven temperature heat up rate too fast especially in combination with a high moisture content part Improper charge patter too large rolled or folded Mold temperature out of spec e Vacuum too low improper vacuum cycle Low cure time under e Press closure speed to fast air trapped in laminate Tooling Corrective Ac
31. sible e Verify correct molding temperature Tooling Optimize mold design for best flow conditions 407 South 7 Street Noblesville Indiana 46060 317 773 1766 www idicomposites com Page 21 44 Laking IDI Composites international THERMOSET MOLDING COMPOUNDS porosity Laking can also be noticed after prime as soak in Laking is an irregular dull area on the surface of the part The dull area may be associated with Probable Cause Material Differential shrinkage Process Too low a pressure on the part during molding usually on vertical walls e Molding on stops e Load pattern weight too low Under cured part e Cold spots on mold Tooling Corrective Action Material e Select different shrink additives and or levels Process e Maintain pressure on material during molding Do not mold on stops or flash Verify load weight is correct and not too low e Verify mold temperatures e Increase pressing speed Tooling e Equip press with parallelism control 407 South 7 Street Noblesville Indiana 46060 317 773 1766 www idicomposites com Page 22 44 Composites iD international THERMOSET MOLDING COMPOUNDS Mold Marks A mold mark is a lump depression or line that occurs in the same location of every part due to a damaged mold Probable Cause Material Process Tooling e Damage to the cavity of the mold due to
32. ss e Rough handling e Rough bypass e Shipping racks lack necessary padding No use of in process racks parts are stacked on each other Squared edge on part at mating surface with adjacent parts Tooling Improperly designed secondary fixtures non padded all necessary areas e Mold defects on edges or flash stuck to shear edge Corrective Action Material e Increase compound viscosity Process e Utilize transfer lines and other hands off processing techniques e Train workers in proper handling techniques Improve shipping procedures and monitor part quality e Improve shipping rack repair procedures Add external mold release and clean e Slow ejector speed e Slow press closure rate e Relocate charge Decrease molding pressure Tooling e Design secondary fixtures properly and coat them with soft materials to absorb shocks e Preventative maintenance on molds and fixtures e Periodically clean flash on shear edges and gummy deposits of styrene e Polish tool surface 407 South 7 Street Noblesville Indiana 46060 317 773 1766 www idicomposites com Page 6 44 Composites iD international THERMOSET MOLDING COMPOUNDS Contamination Foreign material in the laminate Probable Cause Material Foreign material in SMC compound raw materials Process e Foreign material from the molding presses Tooling Corrective Action Ma
33. t Noblesville Indiana 46060 317 773 1766 www idicomposites com Page 32 44 Composites iD international THERMOSET MOLDING COMPOUNDS Sander Scratches Scratches in the substrate result from a sanding operation These scratches usually appear as very fine circular scratches Probable Cause Material Process e Sanding curved areas of part with a flat sander e Improper grit size paper e Sanding Class A surface to remove die marks e Repair procedures for all defects e Poor flash removal methods which require additional sanding e Excessive loading of sandpaper with sanding debris Tooling Corrective Action Material Process e Establish specification describing grit size for specific operations Hand sand curved areas that require sanding e Repair die marks on mold not on parts e Automate flash removal to eliminate error e Specify paper grit size for every repair method e Specify sandpaper change interval e Clean debris from unloading fixture or racks Tooling 407 South 7 Street Noblesville Indiana 46060 317 773 1766 www idicomposites com Page 33 44 Scratch Composites iD international THERMOSET MOLDING COMPOUNDS A scratch is similar to a gouge but is deep enough to require fill repair material A scratch can usually be feather sanded out Probable Cause Material Process e Rough handling Improperly designed secondary fixtures
34. terial e Check for foreign materials in molding compound and cut out if necessary e Check for foreign materials in raw materials Process Tooling 407 South 7 Street Noblesville Indiana 46060 317 773 1766 www idicomposites com 7 44 Composites iD international THERMOSET MOLDING COMPOUNDS Crazing Surface Cracks Probable Cause Craze cracks are hairline cracks that do not go through the entire thickness of the part These cracks usually occur in groups Craze cracks can appear similar to porosity on painted parts Material Process e Mechanical overstressing caused by part sticking in the mold or rough handling Poor material flow pattern around mash offs core pins mold outs e Thermal stresses induced by mold temperature or by non uniform part cool down e Charge pattern changed by adding small pieces to make up weight e Ejector pins e Thick to thin wall thickness variation Tooling e Secondary fixtures improperly designed e Thick to thin wall thickness variation Ribs too thick with respect to wall thickness e Cored holes or slides too low from designated surface position Corrective Action Material Process e Train workers in proper handling techniques Cool parts at a uniform rate Design charge pattern to minimize improper flow behavior Do not use makeup pieces in charge pattern e Minimize mash offs e Slow ejection system to reduce eject
35. tion Mold shear edge is too tight not allowing air to bleed out Tool Deflection Material e Check for fiberglass wet out e Check material for contaminants and check for moisture contamination e Evaluate viscosity levels affect on blisters look at high medium and low Use less reactive catalyst e Select different shrink additives e Verify material is not dried out Process Increase material flow distance e Increase molding pressure e Pyramid charge in center of the tool e Load pattern location size thickness Appropriate vacuum amount and timing position e Appropriate press closure speeds Appropriate mold temperatures e Appropriate cure time Do not use makeup pieces in the charge e Be certain mold shears are clean with at least 0 004 of flash Tooling e Check for mold deflection e Check for Platen parallelism 407 South 7 Street Noblesville Indiana 46060 317 773 1766 www idicomposites com Page 3 44 Composites iD international THERMOSET MOLDING COMPOUNDS Bond Failure Failure of a bonded assembly usually at the interface of the adhesive and the substrate Probable Cause Material e Out of spec SMC Process e Gel time of adhesive too short to permit proper bonding e Bond not fully cured before clamps are removed Improperly prepared bond surfaces e Mix ratio of the two component adhesive is off e Moisture contamination of ad
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