Electronics Forum | Thu Mar 06 10:57:28 EST 2003 | Mark
What are the recommended stencil apertures for a TSOP40. Lead pitch 0.48mm & lead width 0.21mm. And direction of squeegee print over the aperture? Recommended Stencil thickness? Recommended aperture reductions? Recommended pcb pad sizes? Recommended
Electronics Forum | Tue Mar 11 09:33:06 EST 2003 | davef
I'm wrong about the MPM AP. I got my model designation crossed-up and was thinking of an older unit. I apologize to MPM for for my unfair criticism of their product.
Electronics Forum | Fri Mar 07 14:09:16 EST 2003 | davef
Q1: What are the recommended stencil apertures for a TSOP40. Lead pitch 0.48mm & lead width 0.21mm. A1: We've talked about this previously here on SMTnet, for instance check the fine SMTnet Archives: http://www.smtnet.com//forums/index.cfm?fuseactio
Electronics Forum | Fri Mar 07 21:02:21 EST 2003 | neil
When printing below .5mm pitch, the recommended stencil thickness is 5Thou, laser cut. Do not use any reduction and ensure wherever possible the pad to space ration is 1:1, the length of the pad is not as important as the gap between adjacent pads. T
Electronics Forum | Sat Mar 08 11:04:47 EST 2003 | Joe
Mark, You've already received some good advice from the other posters. The one thing I would add is that even if you solve your printing issues on this type of part, the relative small quantity of paste may be prone to soldering problems. Ever s
Electronics Forum | Thu Jun 14 13:12:53 EDT 2012 | scottp
I haven't been in a bad enough situation to try it yet, but I had a conversation with Alpha Metals when we started doing 0.4 mm pitch and they mentioned that if we got into a situation like yours we could send them a board and they'd modify the artwo
Electronics Forum | Thu Jun 14 21:48:41 EDT 2012 | kmots15
We work with a lot of larger boards over 24", haven't run into this issue yet. I agree with scott could be your board supplier if they are lower quality, from something as simple as unit conversions in CAD to dealing with different temperatures. A
Electronics Forum | Fri Jun 15 18:22:49 EDT 2012 | stentech
Our lasers are accurate to +/- approx. 5 microns over 20 "X-Y. I have seen boards 18 x 24 stretch 7mils. I would agree with others, the only way is to send a board to you stencil vendor so they can edit the file to match the board. This is very commo
Electronics Forum | Tue Jun 20 02:51:52 EDT 2000 | Leland Woodall
Gary, We've experienced the same problem in the past, and found that moving the stencil apertures closer together solved the dilemma. This was a much easier solution than having to redesign the PWB. Leland
Electronics Forum | Mon May 27 16:17:30 EDT 2013 | nikyta
Hi Eric, you have the right reduction on the stencils apertures? Also, a very oxidized solder paste can -and will do- promote and increase both the tombstoning as well as the solder balls.
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