Electronics Forum | Thu Jun 16 08:31:15 EDT 2005 | jh0n!
The most part I have the most difficulty with is a 16mil QFN. We found that reducing stencil thickness to 4mil, and reducing aperatures for the IC by 20%, and setting local fiducials to the IC helped immensely. We used to get 75% or more bridged ou
Electronics Forum | Thu May 18 10:20:55 EDT 2006 | slthomas
Russ asks good questions and I think Chunks pretty much nailed it. Aspect ratio (aperture width/stencil thickness) s/b 1.2 minimum (I like 1.5 if I can get it). If your aperture width = lead width (.008"), yours is 1. Tough to get consistent paste r
Electronics Forum | Thu Jun 16 22:14:51 EDT 2005 | davef
16 thou pitch parts: Use a 5 thou laser cut electropolished stencil with 0.008"x0.045" apertures and type 3 solder paste. Bridges Connecting or Partially Connecting Adjacent Leads or Lands * Excessive solder paste * Excessive component placement pre
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 | Tue Oct 15 19:27:08 EDT 2013 | swag
See if you can get a sample of Dek's Nano Protek. We use it on all our fine pitch stencils. I'd say it's kind of like car wax for the aperture walls. They operators really like it a bug me every day to order more if we run out.
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 Jan 08 09:23:18 EST 2013 | lock_2002
This is a question regarding soldermask between pins of fine pitch devices. The majority of our production designs end up with at least 2-3 mils of copper thickness on the external layers due to blind vias, wrap plating requirements, etc. Our curre
Electronics Forum | Wed Sep 18 12:31:16 EDT 2002 | dragonslayr
My suggestion is to conduct a Design For Manufacturing (DFM)study on the assembly in question. Pay particular attention to the pad sizes, component lead dimensions and satisfy yourself that those two factors are correct. Given that pads match compone
Electronics Forum | Mon Dec 20 12:50:27 EST 1999 | Wolfgang Busko
Hi Pascal, 0,65mm pitch normally isn�t much of a problem. With 90�m CU I don�t have any experience but would like to know what deviation from nominal value for the pads you get with different PCB-deliveries. In short, for the standard Cu=35�m we se
Electronics Forum | Wed Sep 18 12:35:56 EDT 2002 | stepheno
Fourth - > back to design of PCB. Are there solder dams of > mask between the pads? If yes, that helps. If > not, pay close attention to stencil aperture > width and be sure that the aperture deposits less > paste by 1-2 mils per pad, centered o
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