Electronics Forum | Tue Feb 04 09:03:45 EST 2003 | Russ Roberts
Greetings, I am pretty new to SMT production, and have learned much from this forum. I am getting ready to build a CCA with many 0402 parts that are really close together. I consider these fine pitch. The board also has two QFPS, so my stencil design
Electronics Forum | Fri Aug 21 09:36:50 EDT 2015 | esoderberg
Looking for better design information than is contained in IPC 7525A. Specifically the minimum trough width and length of the step to achieve the necessary paste reduction.
Electronics Forum | Wed May 22 12:32:49 EDT 2002 | pwrgroup
which stencil vendor can deliver aspect ratio and area ratio and the statistical information to the user?It's difficult if the pad is modified.
Electronics Forum | Tue Feb 04 17:24:07 EST 2003 | jonfox
we have some pretty tight 0402 placements and our best fix was to reduce the pad (vertically speaking) from .030x.022 to .020x.022. Fewer tombstones and the paste flows out to the edge of the pads nicely. Only difference is that we have a 6mil sten
Electronics Forum | Wed Feb 05 14:20:45 EST 2003 | Stephen
One thing that worked for me was simply rounding off the pads, making square pads into circlesfor the stencil. It worked but did seem a little strange turning squares into circles for 0603's and 0402's and turning cirlces for BGA's into squares, (bu
Electronics Forum | Tue Jul 19 11:21:50 EDT 2005 | russ
You may want to try reducing the large center aperture on your stencil to 50-70% of the area of the pad. This is what we do with QFNs and it may be applicable in this case also.
Electronics Forum | Mon Jul 18 10:55:26 EDT 2005 | Sylvain
I have a SO-8 mosfet part from Vishay SI7846DP-T1. Am having a lot of solder ball that coming underneath the part. Am currently using a 5 mils with a window design for my stencil. Those anyone have experience or have any suggestion for an aperture th
Electronics Forum | Wed May 22 02:35:26 EDT 2002 | ianchan
hussman, hi, mebbe we get the stencil fab house guys who spend more time in the workshop making more stencils = more revenue, whereas your stencil fab house is more learned and refined? we make it a point to use an inhouse MS-Excel format to key in
Electronics Forum | Thu Jul 21 09:43:10 EDT 2005 | davef
We agree with Russ. The solderballs are probably the result of printing too much paste on the board. In designing your 5 thou thick stencil: * Aperatures for the pads should be identical to a IPC-7351 - SO8 [or worst case http://www.vishay.com/docs
Electronics Forum | Fri May 17 11:36:37 EDT 2002 | Hussman69
Hmmm... Why would you want to to this? I understand your concern, but why not let your stencil house manipulate your Gerber and send you a copy of it before they cut a stencil? Saves you time and money. Sit down with your stencil manufacturer and
