Electronics Forum | Mon Feb 21 03:51:37 EST 2005 | abhirami
Solder paste thickness control is more important in SMT process. What controls do you have? I guess if everyone follows the critical control path, then there are always reduced problems. The issue is no one is perfect. Paste tends to be on the stenci
Electronics Forum | Mon Apr 06 11:58:42 EDT 2009 | c111
Jeong Ju-young You touched them all up with an iron? Wow! We have also had similar issues. What I did to prove there was a board problem was paste one & reflow one bare board with the same chem (noclean) we saw the non-wetting condition. Then applied
Electronics Forum | Tue Oct 22 15:32:09 EDT 2002 | ruppertg125
We are a military contractor and need to build to IPC610 class3. We are receiving many parts with palladium leads and currently use a No-clean solder paste. We have evaluated OA pastes with very little improvements. Without a touch up of all leads th
Electronics Forum | Tue Apr 01 08:59:06 EST 2003 | rdr
Hi all, I've got a question that hopefully someone can provide insight. We have a gold immersion assembly that we believe is experiencing fractures or non wetting on a certain BGA. To be sure that it is a fracture and not a wetting issue I would li
Electronics Forum | Wed Nov 06 10:03:59 EST 2013 | rgduval
Hi, Peter, I'm not an authority on surface finish thickness, and it's effect on reflowing, so, I can't advise on that front. If the boards are a week old, and ENIG, I would not suspect surface contamination. It's always a consideration, of course,
Electronics Forum | Wed Aug 09 15:06:17 EDT 2023 | SMTA-64386426
The first thing I do when looking at a part relative to stencil design, is determine the coplanarity per the data sheet. Ideally your stencil thickness should be equal to, or if needed, greater than the coplanarity. You want the solder paste to com
Electronics Forum | Tue Apr 14 09:38:07 EDT 1998 | Earl Moon
| We are having some difficulty soldering a 240 pin Altera device. We use Alpha WS-609, a very generic profile for that solder paste, and a 6 mil stencil with laser cut apertures (1:1 ratio). This is a 20 mil pitch device (aperture size is 10 mils X
Electronics Forum | Mon Oct 30 16:00:30 EST 2000 | Finepitch Services
Sal, I kind of assume you have paste there to start with... Because sometimes the edge components do not have paste applied caused by the bottom support in the screen printer etc. And if that is the case for one direction, the other direction applie
Electronics Forum | Mon May 14 17:14:07 EDT 2001 | davef
First, consider checking the fine SMTnet Archives. Look for threads on "white tin", in addition to "immersion tin". We�ve had a cuppla good ones of late. Merix [http://www.merix.com] gives a good comparison of different solderability preservatives
Electronics Forum | Mon Mar 30 07:44:12 EST 1998 | Earl Moon
| | | | | We are having some problems with "drawbridging" on 0805 film capacitors. | | | | We have already reduced the pad width from .050" to .040" based on input | | | | from vendor. Defects appear to be random as far as location on the PWB and d
