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Aug 22, 2018 | Stencil life If we don't take SPI machine is given in the equation, another control should be put in place. Buckcho your approach is interesting, but requires a lot of effort. Do you guys think the stencil printer can count the prints for the same program? Or even better have the option to scan the stencil
May 22, 2018 | Stencil deformation patterns metal blades scraping against a metal foil; do it enough times and any stencil will look like that. It's possible the squeegee pressure is set too high, exacerbating the condition. Try reducing squeegee pressure a little at a time, making sure you are still getting a good print. you want enough pressure so that there is no film of paste left on the stencil, but no more.
Feb 28, 2018 | Stencil-less printing? If you need to make changes to a stencil that many times someone is not doing their job properly. In the past 16 years I have had 3 line stoppages due to stencil issues. 2 of those were because the board house made the panel differently than the files they were sent. New board house solved
Feb 16, 2018 | SMT Stencil Design Hi Rob, Thanks. We have very high mix low volume products. Even our stencil suppliers have problem to fix. So we are landing up getting one more stencil after checking the issue in NPI build. we are trying to add up all and have guideline. which is becoming very bulky and not user friendly
Mar 23, 2017 | Tools For Cleaning PCB after Soldering Rob, That is where Bob works. ------------------------------------------------------- There are many companies that exist offering multiple different products and procedures for cleaning pcb assemblies. I agree, in my practice, most companies strive for lean manufacturing processes that eliminate post-soldering cleaning cycles to begin with. Albeit, we have all been told cleaning should be done before and after soldering. In the real world, however, it is much different from what we learn in text book. From a manual cleaning practice stand-point, as you stated Bob, we typically perform a
Mar 9, 2017 | Stencil Manufacturer No adds or Anti-adds, PLEASE!!!!!!! http://www.smtnet.com/index.cfm?fuseaction=search_submit&searchstring=stencils
Jan 11, 2017 | First, why do you have paste on the opposite side of the component. I would recommend having it on the same side. Second, how thick is your stencil? Pin in paste requires thickness, to fill the whole barrel. Stencil should be really thick. Try to manually apply paste(if your stencil is 6mil think
Jun 6, 2016 | Valor mss process preparaton has a stencil tool module that can do just what you want as well as alarm you if for a defined thickness what apertures need attention Is template driven so can save your stencil processing and settings.. Is powerful tool to get first time right stencils...
Feb 11, 2015 | stencil/printing machines for solder paste If you are just prototyping, I would probably go with the Jet printer(I think the paste cartridges are very expensive). If you have some casual runs I would use a stencil printer. Actually I would like to have them both - tweak the paste amount with the Jet and then cut the right stencil ;)
Jan 29, 2015 | I agree with SWAG on this. Nano Coatings make a big difference on paste release. I found when placed on the topside of the stencil, it also helps to reduce stencil wear, though others complained that it affected the solder roll, so most stencil houses now apply it to the bottom side. (I didn't have
Dec 4, 2013 | Automated Stencil Washer I'm investigating replacing my Stencil Cleaner. After searching the fine archives of SMTNET, I'm as clouded as ever..... So let me ask this... Are there any USERS out there who have a stencil washer that they use every day, and are satisfied with? I'd be very grateful to hear your replies
Apr 1, 2013 | Quite sure it is one of the follow things. Squeegees are not tall enough (using after market blades); Are you using a stencil adapter? bottom surface of the stencil must be even with the top of the stencil shelves; printhead assy. is modified, failed, or not put together properly; machine has been
Feb 12, 2013 | Small apperture release from stencil You need a good designed stencil. Contact Steve - He'll make a free article stencil to try out below is his contact info. Steve@usastencils.com 714-636-6211 Good luck!
Feb 12, 2013 | Small apperture release from stencil Hello everyone, I am curious what do you think about stencil type and apperture design for better release on small appertures. I have a PCB with bunch of BGAs with small appertures. We tried with Nikel stencil using DEK's special non stick material for better release but we are still not satisfied
Jul 3, 2012 | STENCIL RACK Does anyone know of a stencil rack supplier besides Bliss? Bliss makes high quality, very strong racks but one ends up paying big $$$ for them as well. Metro Cart used to make a stencil rack of acceptable quality at about half the price of Bliss but unfortunately they discontinued it about a year
Jun 29, 2012 | The stencil doesn't seem to match the pcb. On the pcb there seems to be pads that are wider than others whereas the openings in the stencil seems to be uniform. As Phil mentioned, make sure the gerbers match the stencil. As for no fiducials, that shouldn't be a problem as long as you're using pads
Feb 22, 2012 | SMT Stencil Printer Recommendations Hi, We're looking to buy a second user stencil printer with fully automated alignment and ideally 2D solder inspection. We're looking at DEK and we use their 23" Vectorguard stencils already, but can anyone advise a particular model. Probably something aged mid 2000's onwards. Thanks
Jan 24, 2012 | If you failed math like I did. A 0.005 inch stencil would work fine for those parts. Most stencils are 0.004in for fine pitch 1005s 201s. 0.005in is probably the most common generic stencil. 0.006in generally is if you need extra solder for big parts.
Jul 6, 2011 | The only thing I have ever heard of that prints solder paste (accurately) without a stencil is a Mydata MY500. You can buy thousands of stencils for what this machine cost. You should not have long lead times on stencils. We get ours next day for no extra charge.
Jun 29, 2011 | That is all we have ever used ("Zelflex" by LPKF). They work great. We have 300+ stencils stored in print drawers, probably 3'x3'x5' area. The stencils are also cheaper by more than 1/2 from our supplier. The only stencils we have in permanent frames are 4-mil as they are too easy to damage
May 30, 2011 | Equipment to measure stencil tension This is a requested point from some customers. It's part of the audit check points. But I agree it´s important for the process. You can garantee the stencil is in a good condition after many time using it. If your stencil looses the tension, you can face some issues during the printing process
Mar 21, 2011 | Stencil Inspection At incoming inspection we visually check the stencil against the gerber file (called up on the computer monitor) used to produce it. This is mostly to check that they mirrored the bottom side correctly although we check the top side as well. That is about all we do. Why do you want to kick it up a notch? Have you been having issues with some stencils not being manufactured correctly?
Jan 28, 2011 | Print then dispense in the areas you need extra paste. Why can you not use a stencil which has areas etched away around component patterns to thin the stencil down....for example a 150 micron thick stencil etched to 120 or 100 microns in specific areas. What are the thicknesses of paste you need ?
Dec 28, 2010 | Use a 0.002" to 0.003" thick stencil. Use an electroformed stencil from Photo Stencil or one of the others. Use -500 +635 paste or a -500 paste or type 5 or greater paste. I have printed at 0.008" pitch with 0.004" pads. It can be done.
Oct 31, 2010 | http://www.shanelo.co.za/Article%20to%20assist%20with%20Stencil%20Design%20Guidelines.htm Stencil design
Feb 24, 2010 | We just stencil the part not the pads if you stencil both then you probaly have to much paste the QFN will lift becuse of the center pad. if the question is screen the part or the pad our boards have parts so close to the QFN that stenciling the pcb is A problem. I realy don't see any differance
Nov 13, 2009 | Stencil Printer? It looks like the Zelprint LT300 is LPKF too... The first one was an LPKF Protoprint S, and the second was an LPKF Zelprint LT300. Are there any of these printers that have a device to actually apply the solder paste with consistent and constant pressure? Does any framed stencil work with it ? Like ones from Stencils Unlimited? Thanks, Ryan
Nov 11, 2009 | Stencil Printer? For a manual printer, I like using this one: http://www.lpkf.com/products/rapid-pcb-prototyping/smd-assembly/solder-paste-printing/smt-solder-paste-printer-metal-stencils
Jul 23, 2009 | I look for an international standard for PCB stretch . In case of misplaced solder paste versus stencil we noticed shorts after placement . I found cases where the PCB (image pattern) did not match with the stencil . It was due to PCB or stencil stretch. Philips Consumer electronics mentionned
Jun 2, 2009 | Stencil Design Where do you getyour stencils from, ask them, I buy everything from DEK(Vector Guards) and they help me 100%. Apperture size, we always have cut 1:1 for the BGA's you can try 4mil stencils. But you have to keep in mind what the other parts you have on board as well.
May 26, 2009 | Amkor's MLF guidelines are very similar to Actels. 1 to 1 on the stencil to part pad on the I/O pads, 75% with a grid windowpane, 0.125 mm/5 mil stencil. For example, the Actel area ratio for a 0.3 mm sq. pad and 0.125 mm stencil is 0.6 which seems marginal...even with a type 4 paste.
Mar 5, 2009 | When you measure "solder paste heigth of 7 & 8 mils using a 5.0 mils stencil," are you measuring the top of a flat brick? Sometimes if you snap-off the stencil too fast, the paste touching the stencil walls form peaks along the edge of the brick that are higher than the majority of the paste
Dec 24, 2008 | manual stencil print 2 passes hi,brettc! Our stencil openings no more than 4mm * 4mm, you have a larger component of the pads is more than a 4*4? At the same time, with the thickness of the stencil, I would like to increase the printing speed can be improved to reduce the thickness of the template that?if the component
Dec 23, 2008 | manual stencil print 2 passes It depends how manual is the printer. you need to control pressure and speed. If you control both by hand, it is difficult to discuss results. If the pressure is controlled by the printer, than you should be able to do it by one deposit. Also is the stencil chemical etched or something better . With a bad stencil even a good automatic printer will show problems. Regards, Emil
Dec 22, 2008 | manual stencil print 2 passes we sometimes have problems with solder paste release. we use a manual stencil printer. does anyone have any thoughts on using two passes of solder paste on the stencil? i have found that running the second pass gives me better deposits on the fine pitch component's pads, but it pulls a little off
Nov 13, 2008 | PCB Stencil coined (dent and ding) repairs? My name is James and live in Colorado. Through an interesting turn of events lately I have gotten back into repairing coined PCB metal stencils. I am in a differant industry but have come up with a proven way to fix imperfections in metal stencils. What kind of demand for these repairs might be out
Oct 30, 2008 | stencil to pcb manufacturing tolerance Hi, Hi, 1) Can anyone tell be what is the acceptable manufacturing tolerance from stencil to PCB . 2) what are the methods we can avoid that. 3) What is the method to avoid PCB shrinkage. 4) How can we correct shrinkage 5)Is there any standard gudelines for Stencil designing Please help me out
Sep 19, 2008 | Large Area Stencil Printing Hi, We would like to do low volume large boards, and does anyone know what options there are for stencil printing larger boards. The board we are doing is 412mm x 685mm so it's quite large. Pick and place is ok, just stencil printing. Is there something low cost and manual around? Grant
Sep 16, 2008 | Stencil Design "....over 3500 apertures in a circuit that is about 1 x 1.5 inches..." 8O Yeah, Larry would definitely be the go-to on this one. :P I would think reducing stencil thickness would be your best bet to avoid that ratio problem, but how durable is a .004" stencil with more air than material in it?
Sep 16, 2008 | Stencil Design I am a doer myself but with the turn around and cost on EFORM stencils I prefer to be right and starting with math is always the best way. We have played with reducing apertures even stencil thickness as low as 4 mil. On the side that this component is on we have over 3500 apertures in a circuit
Sep 16, 2008 | Stencil Design Here is the scenario: We are using Lead Free Type III paste. We are using 5 Mil EFORM stencils The part we are having issues with is a SOT883. Stencil design is the SMALL PADs are 10x16mil Large PAD 14 x 24 mil. We are getting some see-sawing of the part and we are getting some shorts
Jul 28, 2008 | Be careful of just reducing your aps. Too much can cause tombstoning if your print is slightly off or your placement isn't right on. Also be careful of the "pac-man" type of ap - it can lean to asty cuts if you wipe off your stencils by hand. Do a simple homeplate and you'll see the differnce . Contact a new stencil house and you can get it cut for free. (sorry stencil guys)
Jun 17, 2008 | Could it be from a dirty stencil, rather than from the pick and place operation? We've seen a number of occurences recently with solder balls near some of our fine pitch components...we eventually diagnosed as dirty stencils...excess solder on the bottom side of the stencil deposited paste
Jun 3, 2008 | DEK VectorGuard stencil system. Anyone out there using this system ? We have been using the older DEK Vectra system. I don't like it, never did, but do like the small storage footprint, and are stencil supplier is showing signs that this system is gonna be obselete in the near future. pros-cons on the DEK VectorGaurd stencil
Jan 18, 2008 | Stencil Storage Solutions I was wondering if anyone knew of any good portable stencil solutions. I am looking for a rolling cabinet that can house 20 stencils without a huge footprint. I also need the cart/cabinet to be closed off(doors or otherwise) so customers do not see them on the production floor. If anyone has a
Sep 20, 2007 | Jimmy So, it sounds like your stencil and board are made to dissimilar versions. Choices are: * Buy new stencil to match the pads on the board * Tweek position of stencil to better match-up with the pads on board, ignoring the fiducials. You may be able to do this by defining the pads a fiducials
Jun 18, 2007 | Agreed.
Mar 29, 2007 | Invar Stencils OK, just finished our prototype build. PWB 7.5" x 10" 16 layers smallest pitch 17mil smallest BGA pitch 30mil (round apertures) smallest component 0402 total of 1492 placements 5 mil stencil foil (invar) Had numerous PQFN packages that always gave us a little problem in the past. ZERO print defects ZERO solder defects after reflow I WILL be purchasing more Invar stencils!! NOTE: Stencil vendor states the Invar foil will be fine to 15 mil pitch and 0402.
Mar 29, 2007 | To use a mini stencil, or not to use a mini stencil. Who out there uses a mini stencil to paste some paste when they replace a BGA and who uses just flux? What are the benefits or both and more importantly - how many times can you do both on the same component / board? Thanks in advance! Chrissie
Mar 6, 2007 | Maybe swimming..
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