Electronics Forum | Mon Jul 01 00:09:47 EDT 2002 | Ben
Hi all How can I clean the white residue between QFP 0.5 mil Pitch? The white residue was created from mistake adding liquild No-clean flux Lonco 23F for reworking clean board. I can clean almost of it by using EC7M cleaning solvent except between
Electronics Forum | Wed Sep 18 06:53:05 EDT 2002 | CH
1) For solder short, pls check the paste height. Too much vol will cause short. For 15 mils use 5 mils thickness stencil if possible. Check profile preheat time to prevent hot slumpof the paste. 2) type 4 powder will be better for 15 mils pit
Electronics Forum | Thu Jan 09 10:58:30 EST 2003 | soupatech
Thanks for the input.... I ordered a 5 mil stencil AND used more tooling under the board. This gave me a much smaller deposit of solder. I wouldn't swear that was my problem but 96 boards later the problem is 99% gone. I believe there was just too mu
Electronics Forum | Thu Jul 03 15:03:39 EDT 2003 | Jim Nunns
My design group wants to change our route keep out around all SMT parts to 5 mil even under the parts with zero standoff. Are others in the industry routing under parts that have no standoff? My fear is that we will get shorting if the mask is scaped
Electronics Forum | Fri Mar 04 10:04:14 EST 2005 | jbrower
We use Alpha UP-78 (Older paste formula) and it works well for what we do. We standardized our stencils at 5mil with a 10% reduction on IC apetures and a home plate design on passive components. Additionally we use laser cut electro-polished stenci
Electronics Forum | Fri Jul 15 13:58:32 EDT 2005 | seaK
Our production is putting QFN40 and QFN56 package on board. With 80% opening on terminal, 40% on thermal pad, we found QFN56 100% forming toe fillet, but it does not work out the same to QFN40. We suspect it's because of the weight of component.....
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 | Tue Aug 01 10:29:43 EDT 2006 | slthomas
It's been a while since I've built with 16 mil pitch, but I have to second the recommendation to go to 5 mil stencils. Night and day as far as release characteristics. The increase in aspect ratio opens up the window a lot. (read = covers up a mult
Electronics Forum | Tue Aug 01 12:38:13 EDT 2006 | razor9114
I would go with a 5 mil stencil as well, we experienced some similar issues with micro BGA's and the area ratio was suspect as well as the MESH size of the paste. We went to Type IV paste and verified our area ratio and everything ran beautifully. Pa
Electronics Forum | Wed Aug 23 16:37:07 EDT 2006 | flipit
If you bought this camera from Universal, it should come focused correctly. I had one of the first 0.5 mil cameras for flip chips. I used it for years and it was out of focus. I finally convinced Universal that something was wrong and they replace
