CO2mpact User Manual
Contents
1. www ulooptics com 10 Less known is that the output plane of polarisation is rotated with respect to the input denoted here by see Fig 5 As the attenuator is rotated the plane of polarisation is ragged6 with it but at a smaller angle It actually reaches a maximum angle before reversing and dropping back to zero This is due to Plane of polarisation Brewster plate incident beam P plane Fig 5 Definition of angles 0 and 9 the residual transmission of the S polarisation which eventually dominates The formula for the rotation is shown here and Fig 6 is a graph D sin 0 zl 3 1 0 7466sin 0 S 40 c T 35 N a o 30 Q 9 _ 25 c o co o o 15 2 10 c ke 5 0 0 10 20 30 40 50 60 70 80 90 Rotation angle of attenuator 6 deg Fig 6 Rotation of polarisation for a pair of uncoated ZnSe Brewster plates This is no problem if the process is polarisation insensitive but where the output beam must have a fixed plane of polarisation e g when the beam will subsequently be reflected off a phase retarder then some corrective action is required to rotate the polarisation back One way to accomplish this is by having a set of static Brewster plates afterwards However quite a few can be needed 6 to ensure that the plane of polarisation remains within 1 of its original direction The number of plates can be reduced by using the coated type although these have2. Tel 44 1438 767 500 Email sales ulooptics com Fax 444 1438 767 555 Web www ulooptics com 20 If SW is in the CLOSE position then the shutter can be controlled via connector PC If PC pin 3 has 5V applied with respect to pin 9 then current passes through fourth opto isolator IC1 emitter and IC1 transistor is turned on This will pull up the gate of TR1 and so turn it on The solenoid will be energised and the shutter will open PC SHUTTER ov Open sig nal Open detect Closed detect Closed signal Locked sig nal Locked detect Open Close control 45V 0V Solenoid return IRL1520 p OPEN CLOSE Fig 2 Internal circuit of LSC01 controller Note that if you wish to control the shutter using a higher voltage than 5V then you need to add an external resistor in series with R4 390R The value should be R 80Veontro 390 Q and its power rating R 6400 W Also note there are no pull up resistors to the status pins They have been left as open collector so that the user can select the correct value according to their supply and desired signal ULO Optics Ltd Tel 44 1438 767 500 Email sales ulooptics com Fax 44 1438 767 555 Web www ulooptics com 21 Beam injector module CB http www ulooptics com docs pdf tdsulo 96 03 pdf This module allows a visible red laser beam to be aligned
3. power handling restrictions 500W Alternatively a second attenuator rotated by an angle in the opposite direction can re align the polarisation exactly In both cases the transmittance curve in fig 4 will be changed ULO Optics Ltd Tel 44 1438 767 500 Email sales ulooptics com Fax 444 1438 767 555 Web www ulooptics com 11 In summary Brewster attenuators are most useful when the laser itself has no means of power control and the process is polarisation insensitive The polarisation must also be linear Coated Brewster Plates By coating one surface of each plate with a special coating it is possible to enhance the reflectance of the S polarisation to 98 from 50 at the expense of a slight loss to the P polarisation 99 transmission instead of 100 The result is that the minimum transmittance through the attenuator is now much lower at 0 04 2 of 2 The coating is a complex stack of layers so the absorption limits the laser power to around 500W However this is the recommended limit for the CO2MPACT series anyway The corresponding curves for Fig 4 and 6 above are shown below in 7 and 8 Note that the transmission curve closely follows Malus amp law T cos 0 for a perfect linear polariser Note also that for a perfect polariser the plane of polarisation in the output would follow the attenuator all the way round to 90 For the coated attenuator however the polarisation will still flip back to zero but from a h
4. surface These will not function at other wavelengths A flat window tilted to operate at the Brewster angle of incidence is usually referred to as a Brewster plate or window In an attenuator two of these are mounted in a d darrangement as shown in Fig 3 Because of the 67 4 angle of incidence when ZnSe is used the plates need to be 2 6 times longer than their width in order to present a square profile to the beam The d dconfiguration corrects for the beam displacement Fig 3 Arrangement in a V configuration of 2 x ZnSe Brewster plates There are 4 air ZnSe interfaces 2 plates in the attenuator each transmitting 100 Tp and 50 33 Ts Consequently after all 4 interfaces the nett transmittance is 100 Tp and 6 4 Ts These values represent the limits for the transmittance of an attenuator To vary the transmitted power the plates are rotated about the beam axis If 0 represents the angle between the direction of polarisation in the incident beam and the P plane of the Brewster plates then the transmittance of the attenuator is given by T 1 0 9358sin 0 2 Fig 4 plots the results in a graph 100 90 80 70 60 50 40 30 20 10 0 0 10 20 30 40 50 60 70 80 90 Rotation angle of attenuator 0 deg Transmission T 96 Fig 4 Plot of transmission against rotation angle for a pair of uncoated ZnSe Brewster plates ULO Optics Ltd Tel 44 1438 767 500 Email sales ulooptics com Fax 444 1438 767 555 Web
5. the cap while to adjust it amp distance from the lens to give the correct stand off 3mm unscrew the lock ring and screw the threaded tube in or out Then tighten the lock ring The gas nozzle inlet allows a gas purge to be directed through the nozzle With the standard lens a pressure of up to 5 bar is possible The inlet requires 6 4 tubing ULO Optics Ltd Tel 44 1438 767 500 Email sales ulooptics com Fax 444 1438 767 555 Web www ulooptics com 17 Shutter head unit C SU http www ulooptics com docs pdf tdsulo 96 09 pdf Description and use The shutter head uses a rotary solenoid to flip a Supermax coated Silicon mirror in and out of the beam When the shutter is closed the beam is reflected onto a water cooled beam dump When open the beam passes straight through the unit The open position is the electrically activated state of the solenoid Therefore if the power were to fail the shutter will close a spring provides the force LEDs on the shutter head indicate the status red for open and green for closed The open and close positions are detected by opto reflective switches Power is provided via the 9 pin D connector and open close status can also be monitored via this connector An optional Laser Shutter Controller LSC01 supplies power and monitors the status of the shutter Note that the shutter is intended as a safety shutter and not for brief timing exposures Using the LSCO01 typical opening and closing tim
6. the rear panel 9 pin fDo socket labelled SHUTTER If required the shutter can be controlled and monitored remotely via the other 9 pin Mo plug labelled PC Operation The front panel push button switches the controller mains power on or off It is illuminated when powered on Before switching on check that the toggle switch is in the closed position or if being controlled from a PC that a amp lose signal is being sent This will ensure that the shutter does not open unexpectedly on power up The toggle switch opens or closes the shutter The left position will open the shutter and the right position will close the shutter Note that if the controller is switched off at the mains the shutter will default to the closed position The red OPEN indicator will light when the shutter is open The green CLOSED indicator will light when the shutter is closed Note Other ULO Optics shutters dcSU types have a manually operated lock that allows the shutter to be locked in the closed position only The yellow LOCKED indicator will light to indicate this The CO2MPACT shutter C SU does not have a lock so the yellow LED is inactive The status of the shutter can also be monitored via the rear panel 9 pin PC connector Opto isolators are used to give a grounded signal to indicate open closed or locked and a high impedance for the inverse The shutter can be opened by applying 5V to the shutter enable pin 3 relative to GND Note that to operate the shutt
7. 1mm increments are engraved on the outer sleeve In total there is 20mm of movement engraved as 10 5 0 5 10 with 1mm lines A locking knob is provided to secure the focus setting The tube does not rotate as it slides a pin at 90 to the locking knob rides in a slot to prevent rotation This in turn prevents any beam wander from residual lens centring errors Both ends of the focusing unit have the thread to take the thread inserts Centring cell C CC The centring cell has the two dead insert connections on each side one for the input and one for the output By adjusting the 3 screws in the body side it is possible to laterally adjust one with respect to the other either to precisely align the output to the beam or to introduce a deliberate offset Note that the screws need to be loosened on one side before those opposite can be screwed inwards All 3 screws must be tightened once the adjustment is made ULO Optics Ltd Tel 44 1438 767 500 Email sales ulooptics com Fax 444 1438 767 555 Web www ulooptics com 16 Lens nozzle assemblies C LNxx http www ulooptics com docs pdf tdsulo 96 Op pdf The lens and nozzle assemblies come for 3 standard lens focal lengths 38 63 and 100mm The lenses are mounted in a separate cell that is screwed into the nozzle section The C LN100 is a C LN63 plus an extension piece and is shown above The clear aperture inside the lens assembly is 17 5mm The copper nozzle is removed by unscrewing
8. 4 TAS ONO Te 24 Focusing lenses 7 5ZLF38 7 5ZLF63 and 7 5ZLF100 24 Silicon mirrors 9 88183 00 and 10S183 00 e eese 25 Phase retarders 9 88PR3 90 and 10SPR3 90 eese 25 Silicon miror 119193 TO 25 Beam combiner 9 8ZBS3 45 H ccccccccceceseeeeeeeeeeceeeee nnne nn 25 Brewster windows ZBW5320MP and EZDBWZOOMD eere 25 Beamexpander output lens 11ZLF63 00 0 cece ccceceeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeaees 25 Beamexpander input lenses nnns 25 ULO Optics Ltd Tel 44 1438 767 500 Email sales ulooptics com Fax 444 1438 767 555 Web www ulooptics com Introduction As the name suggests CO2MPACT beam delivery is intended for small CO lasers in this case up to 500W power and with beams up to about 12mm diameter From the laser output to the work piece the beam delivery consists of components that enable the beam to be handled with efficiency The parts are easily assembled with the aid of the thread inserts and the system can be firmly secured to a bench top with the pipe supports In the following sections each of the individual parts is described Some require very little explanation but others require considerably more detail in order to explain the optical function and its use d xample of an assembled system From top left to bottom right laser mount attenuator beamexpander pipe pipe support shutter beam injector corner mirror block e
9. ULO Optics CO mpact User Manual Beam Delivery System for sub 500W lasers ULO Optics Ltd Tel 44 1438 767 500 Email sales ulooptics com Fax 44 1438 767 555 Web www ulooptics com ULO Optics OCU WG MEI m 3 Laser mounts C LM and C LMA ssssseese enn emen nennen nnn 4 TEI WN zi cT Em 4 B am OL o o NER RTI Rc 5 EIERE 5 Retractable mount C RM ci cceccecccee cesses eeeeeeeeeeeteeeeeeseseeeeneseeseeeeeeueeeeeseneeeesens 6 Poe 5 0 6 910 g 8 O ho a eRrene ee negate eee a E ee eee ee ee eee ee 6 Beamexpanders CDEN eese eeessi esee eeee ne nhai nn nnai anna rni nna si rne na in rena 7 BEAIMeX DANCE INCOLY METTE ST 7 Manual attenuator C MA cece ce ceecccceccececceeeeeeceececeeeeceeeeceeeeeeneeeeneeeeeeeeeneaeeneaeenes 9 miiltieile Foigoer irziiro EE 9 PTS TE e TEE 13 Ke tele Ee E 14 Principle Of Operat ON EEN 14 Corner mirror block Ces EE 15 Fine focus adjustment CEA 16 centring e iO 00 16 Lens nozzle assemblies CGUNanx cesses eeeeenseseeseeeeeegeseeeeeneeeaees 17 Snutter head unit Sco E 18 Description and use 18 Int Ve fem 18 Laser Shutter Controller LSCO1 esses enne 19 E el s elle EE 20 Qr E 20 NC UN OA eet 20 Beam injector module C EE 22 xolg m H NEM 22 Dode RE 22 Oe ETIN T m 22 Alignment of Visible Beam cesses seeees eene nnnm nnns 22 i WIEC COW ener 23 nie e Ke El 2
10. alignment a various places working your way from the laser to the work piece Any odd mode pattern may indicate that the beam is reflecting off the inside of a pipe or is being clipped somewhere Fig 1 Aligned left and mis aligned right beam burns ULO Optics Ltd Tel 44 1438 767 500 Email sales ulooptics com Fax 444 1438 767 555 Web www ulooptics com 23 Thread adapters Should the need arise where you wish to couple other beam delivery equipment to the COzmpact range these 4 adapters should help They have the M29 x 1mm thread and a 4 32UN thread in the male and female combinations The optics The list of optics used in the COzmpact beam delivery is as follows Focusing lenses 7 5ZLF38 7 5ZLF63 and 7 5ZLF100 These 3 lenses are used in the C LN nozzle assemblies They are all 19mm diameter and have an edge thickness of 2 0mm When mounted in a nozzle assembly the clear aperture will be 17 5mm The effective focal length EFL back focal length BFL and flange focal length FFL are as follows see Fig 1 7 5ZLF38 7 5ZLF63 7 5ZLF100 100 0mm EFL FFL BFL zi ULO Optics Ltd Tel 44 1438 767 500 Email sales ulooptics com Fax 44 1438 767 555 Web www ulooptics com 24 Fig 1 Definition of EFL BFL and FFL All the lenses are made from laser grade CVD ZnSe to the optimum meniscus form for focusing purposes and each surface is anti reflection AR coated for 10 6um Silicon
11. am wavefront radius to be adjusted The central position being factory set for infinity focus However the actual setting needed will be determined by experimentation The magnifications available are listed the Table 1 below along with input clear apertures Note that the lowest and highest magnifications possible in the housing are 1 3 and 7 0 respectively Although a longer housing is possible to cover magnifications 7 to 12 Mag 13 16 20 25 30 35 40 50 60 70 dch 19 5 159 127 10 2 8 5 7 3 6 3 5 1 4 0 3 6 CA mm Table 1 Input clear apertures The output lens is common to all magnifications and together with the mechanical length of the slide and lock slot determines the focusing range of 1 metre through infinity to 1 1 metre Thus the beamexpander can be used as a dong working distance focusing lens When used as such however the focal length is equal to the working distance 2G divided by the magnification m i e F G m E g when a x7 beamexpander is adjusted to focus over 1400mm the effective focal length is 1400 7 200mm not 1400mm You can use F 200mm in the equation above for spot size S provided D is the input beam diameter alternatively you could use 1400mm for amp and the output beam diameter for both are larger by the magnification factor Beamreducers Occasionally someone may wish to use a beamexpander in reverse as a beamreducer In principle there is no reason why t
12. ate set up monitor the laser power through the attenuator and adjust for the maximum power reading In most lasers the plane of polarisation is either vertical or at 45 to the vertical meaning that the arrow will either be uppermost or 45 to one side Finally lock the attenuator to its supports both ends Turning the graduated ring will now vary the transmitted power dumping the rest inside the body For prolonged periods of dumping power and for higher powers the body will get hot Fitting the water cooled jacket will then be advisable ULO Optics Ltd Tel 44 1438 767 500 Email sales ulooptics com Fax 44 1438 767 555 Web www ulooptics com 13 Reflection isolator Ch http www ulooptics com docs pdf tdsulo 96 O8 pdf Principle of operation Optically the reflection isolator is identical to the manual attenuator but is not intended to allow the out going beam power to be varied It is installed in the system to allow the out going beam to pass without loss However any beam travelling back towards the laser and polarised in the orthogonal direction will be attenuated Using two uncoated Brewster plates the transmittance will be 6 4 and two coated plates about 0 04 In some laser systems this function is useful to prevent a beam reflection from the work piece travelling all the way back into the laser cavity where it can cause instability to the power or damage in a high power laser The laser user will need to consult the las
13. e material provided the angle of incidence is equal to the Brewster angle This is not so when the polarisation is in the perpendicular direction as shown in Fig 2 known as amp polarisation P polarisation S polarisation Fig 1 P polarisation Fig 2 S polarisation If there is a mixture of polarisations then the situation is more complex but the transmitted light will contain less of all polarisations except P By using a series of interfaces eventually the transmitted light will be all P and some of the laser beam power is lost Obviously a window as 2 air material interfaces The value of the Brewster angle is calculated by I Brewster tan n 1 Where d amp is the refractive index of the material Table 1 lists the values for ZnSe against different wavelengths ULO Optics Ltd Tel 44 1438 767 500 Email sales ulooptics com Fax 44 1438 767 555 Web www ulooptics com A um n Jj lewewter Tp Ts 0 633 2 591 68 90 99 90 47 28 2 438 67 70 99 99 49 73 2 422 67 57 50 01 2 403 67 40 50 33 12 0 2 393 67 32 100 50 51 Table 1 ZnSe Brewster angle data with srewster set at 10 6u m value The Brewster angle does not vary much with wavelength so the transmittance does not vary greatly once set for a particular wavelength An attenuator based on the Brewster angle will work well over a broad range of wavelengths NOTE there are versions for 10 6um where coatings have been applied to the
14. ent Synrad and Spectron There is a small amount of height adjustment available by loosening 2 screws on the supportG side Standard heights are 73 78 81 and 123mm ULO Optics Ltd Tel 44 1438 767 500 Email sales ulooptics com Fax 44 1438 767 555 Web www ulooptics com Beamexpanders C BEx x http www ulooptics com docs pdf tdsulo 96 O1 pdf Beamexpander theory As the name suggests a beamexpanderG purpose is to enlarge the diameter of a laser beam This is done for two possible reasons 1 When focused a larger diameter beam will give a smaller spot Thus a beam is expanded to produce higher energy densities on the target 2 A large beam also has a smaller divergence and does not change its diameter as much when propagating over many meters unless deliberately defocused In a flying optics type system this helps to keep the energy density at the focus constant as the optics vary their distance from the laser and also reduces the focus shift due to the wavefront curvature variation The above two points can be expressed mathematically by the equations AM XF S 1 Where S Focused spot diameter F Lens focal length D Beam diameter at the lens M Beam M squared factor not the magnification Note that the focusing lens must be diffraction limited 4M Do 2 2 Where Do Beam waist diameter 0 Beam far field divergence full angle The right hand side of this equation is a constant for a
15. er from a computer set the toggle switch to the CLOSED position Fig 1 D connector pins on rear of LSCO1 PC SHUTTER 1 2 3 4 5 5 4 3 2 1 00000 00000 0000 O0O000 6 7 8 9 9 8 7 6 SHUTTER pin pin 12V no connection Shutter enable Shutter enable 5V open OV close no connection no connection Locked GND locked high Z unlocked Closed GND closed high Z not closed Open GND open high Z not open no connection no connection Locked 12V locked Closed 12V closed Open 12V open Circuit Operation The shutter solenoid is connected between connector SHUTTER pin 1 12V and pin 3 TR1 drain When switch SW is switched to CLOSE the gate of TR1 is pulled low by R2 and so TR1 is switched off Therefore no power is applied to the solenoid and the shutter assumes the default closed position When SW is switched to OPEN TR1 gate is pulled up to 12V and TR1 is turned on This provides a current path from 12V through the solenoid to Ov and so the solenoid energises and the shutter opens The shutter status switches are connected between 12V and connector SHUTTER pins 6 7 and 8 When the OPEN status switch closes it connects R1 to 12V so that LED1 lights and current flows through the emitter of the opto isolator IC1 causing the output transistor to turn on Operation of the CLOSED state is similar Note that the d ocked function and LED3 are not relevant to the C SU ULO Optics Ltd
16. er manufacturer to estimate what power level can be tolerated by the cavity and hence whether coated or uncoated plates are necessary or even more than one isolator in series Circularly polarised back reflected 1 d waveg phase retarder Circularly polarised out going beam Linearly polarised back reflected Brewster dumped plates Linearly polarised out going beam fully transmitted Fig 1 Set up required for the reflection isolator As mentioned above the backward reflection must be polarised orthogonal to the out going beam so somewhere in the system between the isolator and work piece the polarisation must be rotated through 90 in order for the isolator to work This will happen in a system where a A 4 1 4 wave or 90 phase retarder mirror is used to convert the linearly polarised beam into a circularly polarised one Such an arrangement is ULO Optics Ltd Tel 44 1438 767 500 Email sales ulooptics com Fax 44 1438 767 555 Web www ulooptics com 14 common and is widely used for metal processing The metals Aluminium and Copper are particularly noted for sending back an unwanted reflection towards the laser Fig 1 shows the arrangement that is required The out going beam is polarised for maximum transmission through the isolator and 45 to the S and P directions for the phase retarder mirror After reflection the beam is circularly polarised and is used in this state to process the material If a backwa
17. er window works best if it has a slight wedge 16i 39 However this wedge deviates the beam going through it But by using an identical second window with the wedge orientated opposite to the first the angular beam deviation is corrected The beam lateral displacement is also corrected because both windows have the same thickness The windows are 53 x 20 x 3mm Angled at 67 4 to the incident beam they present a 20mm square profile Beamexpander output lens 11ZLF63 For all C BE magnifications this is the common output lens It is a standard lens and is used extensively for other applications Beamexpander input lenses There is a different input lens for each magnification Each is shaped to correct the spherical aberration of the output lens ULO Optics Ltd Tel 44 1438 767 500 Email sales ulooptics com Fax 444 1438 767 555 Web www ulooptics com 25
18. es have been measured at 30 and 60 msec respectively as defined by the period in which neither limit switch amp ees the mirror Note that these times cannot be equalised due to the solenoid limitations The clear aperture is 19mm The beam dump is water cooled via the connectors 6 4 M6 For a water temperature rise of AT C and a laser power P Watts the water flow rate should be 0 014P AT litres min e g for a 10 rise in water temperature and 500W the flow is O 7 litres min The shutter heads are provided with retractable screw rings for mounting to beam pipe Before installing the shutter check that the beam is centred to the beam pipe Also note that there is an input and output side Sending the beam in from the wrong side will cause it to hit the rear of the mirror mount The shutter will operate in any orientation Internal circuit For those who wish to provide their own controller the drawing below shows the internal circuit of the shutter head Note that only 5 pins on the connector are actually used Any controller must supply 12V to pin 1 and be able to provide up to 1A To open the shutter pin 3 is taken to OV This can be done via a simple switch or using a transistor The reflective opto switches OPB704 detect the presence of the mirror When the internal transistor sees light from the diode reflected off the mirror it conducts pulling the base of the 2N3904 up and causing it to conduct The latter acts as a current bo
19. his cannot be done however there are a few cautions to bear in mind 1 The power density at the output will increase with the square of magnification m m being the magnification of the beamexpander 2 The far field divergence angle of the output beam and any angular misalignment errors of the beam increase by the magnification m Centring the beam to the beamexpander will therefore be more critical and it may grow more rapidly than you expect 3 The focusing becomes much more critical The range will be approximately 1000 nf through infinity to i 1000 m millimeters Therefore some short focusing distances are possible It is advisable when setting up the beamreducer not to have any other optics further down the beam until the focusing is set correctly This will prevent possible damage from having a focused beam accidentally directed onto another optical component ULO Optics Ltd Tel 44 1438 767 500 Email sales ulooptics com Fax 444 1438 767 555 Web www ulooptics com Manual attenuator C MA http www ulooptics com docs pdf tdsulo 96 07 pdf Principle of operation The principle of operation is based on the dBrewster angled When linearly polarised light is incident on an air optical material interface uncoated usually some of the light is reflected and some transmitted However when linearly polarised in the orientation shown in Fig 1 known as polarisation there is no reflected light 10096 is transmitted into th
20. igher angle 100 90 80 amp 70 ke 60 9 2 5 E 40 c S 30 ke 20 10 0 0 10 20 30 40 50 60 70 80 90 Rotation angle of attenuator 6 deg Fig 7 Plot of transmission against rotation angle for a pair of coated ZnSe Brewster plates 2 80 c 70 N e 60 Q o Sp c o co o 9 e 20 2 20 c ke S 10 z 0 0 10 20 30 40 50 60 70 80 90 Rotation angle of attenuator 6 deg Fig 8 Rotation of polarisation for a pair of coated ZnSe Brewster plates ULO Optics Ltd Tel 44 1438 767 500 Email sales ulooptics com Fax 44 1438 767 555 Web www ulooptics com 12 Attenuator use The attenuator has a graduated ring with lock screw Turning this ring rotates the Brewster plates inside and the scale reads the nominal transmission some later versions may have some extra numbers relating to the transmission with coated plates With the ring set to d006 note that the P plane of the Brewster plates align with the large arrow at the opposite end of the barrel This arrow also shows the preferred direction of laser beam travel more relevant for the coated plate version With the ring locked in the 100 position mount the attenuator in the system and rotate the whole body until the large arrow lies in the known plane of polarisation The P plane of the Brewster plates will then coincide with plane of polarisation and the transmission will be at a maximum 100 For a more accur
21. in one version C BPE50 70 and 85 to 125mm in the second C BPE85 125 As with normal beam pipe thread inserts are used to connect to other parts and the bore is the same 19mm ULO Optics Ltd Tel 44 1438 767 500 Email sales ulooptics com Fax 444 1438 767 555 Web www ulooptics com Retractable mount C RM The retractable mounts are used in pairs and fixed either side of a part that you may need to remove from the system without upsetting the position of other components Alternatively they can be used to lock other components in a certain azimuth orientation Attach them to the component using thread inserts and then use their coupling rings to connect to the beam pipe The coupling rings once unscrewed from the thread insert are simply pulled back to allow the part to be lifted out The beam injector and shutter units are supplied with these mounts Pipe supports C PS http www ulooptics com docs pdf tdsulo 96 04 pdf The pipe supports are to allow the beam pipe sections to be firmly clamped to a work surface at a height to match your laser They consist of 4 parts the base a middle section and a V section to hold the pipe and the clamp The base has 2 slotted holes to allow mounting to optical tables that have a hole spacing of 25mm or 10 The hole separation is 7bmm 30 The middle section is the piece that is chosen to bring the beam pipe up to the correct height Common laser types catered for are those made by Rofin Coher
22. mirrors 9 8SIS3 00 and 10SIS3 00 Made from monocrystalline mirror grade Silicon these mirrors are fitted into the C CM corner mirror blocks The mirror block will take either size 25 or 25 4mm diameter They are coated with ULOG Supermax coating giving 99 85 reflectance at 10 Gum and 45 incidence The mirrors also are of Gero phasedtype Phase retarders 9 8SPR3 90 and 10SPR3 90 These differ from the above Silicon mirrors in the coating The SPR type is designed to convert the linearly polarised laser beam into circular polarisation by means of a 90 phase shift difference retardance between the S and P components This has processing benefits for some materials e g metals They fit into the C CM corner mirror blocks The mirror block itself has to be orientated with respect to the plane of polarisation as illustrated below A retractable mount C RM may therefore be needed on the input side Silicon mirror 11SIS3 00 This Supermax coated mirror is 28mm diameter 1 19 and is used only in the C SU shutter unit With the shutter closed it reflects the beam into a water cooled beam dump Beam combiner 9 8ZBS3 45 R This optic finds use in the C BI beam injector unit Angled at 45 incidence the CO laser beam will be transmitted while the red visible laser strongly reflected off one surface Brewster windows ZBW5320MP and EZBW5320MP Brewster windows for use in attenuators and reflection isolators are made as natched pairs A Brewst
23. ner diameter of 19mm Slots at each end allow some leverage to tighten against a stop and undo them again ULO Optics Ltd Tel 44 1438 767 500 Email sales ulooptics com Fax 444 1438 767 555 Web www ulooptics com Beam pipe C BPxx http www ulooptics com docs pdf tdsulo 96 04 pdf Beam pipe serves as a shroud to the laser beam so that accidental blocking of the beam cannot occur In particular for Health and Safety reasons an invisible laser beam such as the CO beam cannot be blocked by a part of the body Of course beam pipe also serves to connect the other parts of the beam delivery system together making it a more rigid structure Yet a third reason for its use is to contain a purge atmosphere that has a slight positive pressure This helps to keep dust out of the beam path as well as stabilising the beam from the effects of absorbing gases The standard lengths are 30mm 50mm 100mm and 300mm Using the thread inserts longer lengths can be created An odd length can be made using the extender pipe A 30mm length can also be supplied with a purge nozzle C BPP30 The internal bore is 19mm and connection is made to other components by the thread inserts Extender pipe C BPExx yy Extender pipe is a telescopic section of beam pipe that is used to bridge a gap that does not correspond to the standard lengths of fixed length beam pipe The extending section is a slide and lock mechanism The length range covered is 50 to 70mm
24. ny particular beam so as Do increases 0 will decrease If a beamexpanderG amp magnification is Gn then the input and output beams are related by the following equations Dour min 3 0 Vou H 5 m Where D are the beam diameters and R the wavefront radii see Fig 1 amp is the geometric focus setting of the beamexpander On more expensive models than the COMPACT this will be the value engraved on the focus ring Normally however G is set by experimentation Note that if G is set to infinity beamexpander ULO Optics Ltd Tel 44 1438 767 500 Email sales ulooptics com Fax 44 1438 767 555 Web www ulooptics com has zero optical power the output wavefront radius is not equal to the input wavefront radius unless a beam waist is located at the input Hy o Out ES R Out 5 8 OG D D 2 6 J o d Fig 1 Definition of terms The last equation 5 above relating the far field divergence on the input and output sides can generally be summarised by saying that a angles are reduced by m including beam alignment errors to the optical axis CO2MPACT beamexpanders COMPACT beamexpanders are optically identical to ULO Optics amp BSL12 series BSLs now being phased out The difference is that the CO2MPACT version has a slightly longer body and is modified to take a thread insert at the output end The input end has a built in thread The slide and lock focus mechanism allows be
25. oster to supply the indicator LED and pass the signal for external use via pins 7 and 8 going high to denote detection The reverse biased diode 1N4007 suppresses any back emf when the solenoid is deactivated ULO Optics Ltd Tel 44 1438 767 500 Email sales ulooptics com Fax 44 1438 767 555 Web www ulooptics com 18 D connector 9 way pins 473 880 ei 12V 7 N OPB704 OPB704 8 ia 307 913 307 913 Open signal e Closed signal 1 1 2 3 4 5 00000 OO OO Rotary solenoid Green 35mm 45deg 6 7 8 9 228 6004 343 31 3 1N4007 348 5397 390R 163 533 2 3 Solenoid return 294 312 PCB 10 way r a 1 25mm connector 279 9320 10 way housing 279 9207 Fig 1 Internal circuit of C SU head Laser Shutter Controller LSCO1 P ei d Ki i te umicore QN lt iF Ai i Ko TN r iso a oe i CLOSED LOCKED LASER SHUTTER CONTROLLER MEN ih UMICORE LASER OPTICS LTD 1 2617 48 DX IER TI SHUTTER Fig 1 Front and rear panels ULO Optics Ltd Tel 44 1438 767 500 Email sales ulooptics com Fax 44 1438 767 555 Web www ulooptics com Connections The LSC01 is supplied with two cables a mains cable and one to connect to the shutter head terminated in the D type plugs The controller is powered from an 85V 260V ac supply connected to the rear panel IEC receptacle The shutter is connected using the cable supplied to
26. rd reflection occurs it is reflected off the phase retarder a second time and undergoes another 2 4 phase retardation This second reflection does not indo the first to give a zero retardation but adds to it to give a 2 2 or 180 retardation The result is to re create linear polarisation but orthogonal to the out going beam Therefore the isolator will dump the beam Note that inaccuracies in the phase retarder coating and alignment of the polarisation to the mirror will result in elliptical polarisation in the reflected beam with a less efficient dumping of the power in the isolator Reflection isolator use The isolator is installed in the same way as the attenuator except there is no ring to adjust the power The arrow on the barrel defines the P plane of the Brewster plates and the preferred direction of propagation more relevant for the coated plate version Rotate the isolator in the beam until this arrow is aligned to the direction of polarisation or using a power meter gives the maximum transmittance Then lock in place Corner mirror block C CM http www ulooptics com docs pdf tdsulo 96 02 pdf The C CM corner mirror block uses 25 4mm 19 or 25mm diameter Silicon mirrors coated with the Supermax coating As an alternative though a 2 4 phase retarder may be used The mirror is mounted in a ring that has tip and tilt adjustments which are accessible through two holes in the cover plate The latter holds a conical spring that bear
27. s on the mirror back to provide some restraining force Mirror blocks will be supplied pre aligned to within a few arc minutes so should not need much adjustment If large amounts of adjustment are actually required about 2 are available then check the alignment of the incident beam and whether previous components are correct The mirror can be changed without affecting the alignment To do this undo the two screws that hold the cover plate in place and remove together with the spring Pull on the edge of the mirror to remove or use a piece of tape stuck to the mirror back Replace with the new mirror and screw the cover plate on with the spring in place Note that the large coil of the spring fits into the recess inside the cover plate The mirror blocks accept the thread insert or retractable mounts One of the latter on the input side is recommended as this allows the mirror block to be orientated in azimuth to any angle useful when the corner mirror block contains a phase retarder Note that the clear aperture on the C CM is 16 4mm ULO Optics Ltd Tel 44 1438 767 500 Email sales ulooptics com Fax 444 1438 767 555 Web www ulooptics com 15 Fine focus adjustment C FA http www ulooptics com docs pdf tdsulo 96 05 pdf This adjustable component is intended as a manual focusing device for a lens and nozzle assembly By turning the notched ring the tube with the engraved scale lowers or raises at a rate of 1mm per turn 0
28. until the visible beam is central Do not press down on these screws otherwise you will compress the springs that you are trying to adjust Look for a clean beam Any spurious flares or arcs will indicate that the tilt is so far out that the beam is reflecting off the inside of the beam pipe Next either remove the C BI or retract the beam pipe at the output side Again place a piece of masking tape over the aperture Adjust the two screws X and Y to centralise the beam There is a few mm of movement available and the total area covered is circular When X and Y come loose while unscrewing or go tight while screwing in the laser mount inside has reached the limit ULO Optics Ltd Tel 44 1438 767 500 Email sales ulooptics com Fax 444 1438 767 555 Web www ulooptics com 22 The alignment process is iterative adjust A and B to centralise the beam in the dar field and adjust X and Y for the mear field Finally you may wish to make some fine adjustments with the CO beam on Cross wire C CW This useful item allows you to align the laser beam It is a thread insert with a pair of copper wires and can therefore be screwed in at any location between parts to check for a central beam Once the beam is aligned replace it with a normal thread insert A quick beam burn on card or viewing the beam on a mode plate will show the silhouette of the wires Make adjustments until the silhouette cross is central to the beam You need to check the
29. with the invisible infrared beam This serves to act as an alignment aid further down the beam and as a reminder that the infrared beam is also present Power 6V amp 30mA is required at the jack connector to switch the laser on and light the LED indicator on the side The power supply supplied for this purpose is voltage switchable but should be set to the 6V option Diode Laser Inside the C BI is a visible red 650nm laser of 0 8mW power As is usual for this type of device DO NOT STARE INTO THE BEAM DIRECTLY AND ENSURE THAT YOUR EYES AVOID ANY REFLECTED BEAMS CO Laser Beam This is to be directed into the input aperture Make sure the beam is aligned to the centre of the beam pipe before installing the C BI The CO beam will pass through the ZnSe beam combining optic and emerge at the output aperture together with the visible laser beam Note that the clear aperture of this unit is 14 5mm IF YOU SEND THE CO LASER BEAM INTO THE WRONG APERTURE A SMALL OF THE POWER IS REFLECTED UP TO THE DIODE LASER AND IT S COLLIMATING LENS DEPENDING ON THE POWERS INVOLVED THIS COULD DAMAGE THE DIODE LASER Alignment of Visible Beam Before coupling to the beam pipe stick a piece of masking tape over the output aperture to check that the beam is more or less central Turn the CO beam off Mount the C BI in the system and install a target or cross wire further down the system Use an Allen key to adjust the tip and tilt screws A and B
30. xtender pipe fine focusing unit centring cell lens and nozzle assembly Some short sections of beam pipe are between the various parts This section view shows how a thread insert connects a length of pipe to a corner mirror block ULO Optics Ltd Tel 44 1438 767 500 Email sales ulooptics com Fax 44 1438 767 555 Web www ulooptics com Laser mounts C LM and C LMA http www ulooptics com docs pdf tdsulo 96 10 pdf Coming in two versions these mounts allow the CO2MPACT equipment to be attached directly to the output end plate of the laser The screw hole pattern is arranged to match your laser The central hole is threaded to match the thread inserts see below from which beam pipe and other items can be attached A small amount of clearance in the screw holes will allow some sideways movement to centre the beam to the bore If your beam is accurately perpendicular to the laser end plate then the C LM will suffice however should you need to tilt the beam delivery over slightly to follow the beam then the adjustable version C LMA is recommended This consists of two plates the first being bolted to the laser and the second is adjusted for tip and tilt using the three screws A compressed O ring sits between the plates to provide the G amp pring for the adjustment Thread inserts These stainless steel thread inserts are used to couple together the various parts of the CO2MPACT range They have a M29 x 1mm thread and an in
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