Electronics Forum | Thu Jul 05 09:27:05 EDT 2001 | blnorman
Our solder ball problem is linked to moisture. If the paste sits on the board too long (especially during our humid summer months) we experience the problem. As far as the problem being specific to components or areas of the board, maybe some of th
Electronics Forum | Thu Jul 19 08:00:03 EDT 2001 | doctord
Solder balls or mid chip beads? Remember IPC classification for Class 2 allows mid chip beads encapsulated in flux. Usually on R's and C's first thing I would do is verify .006 laser stencil 10% reduction and the most critical, The paste must be on t
Electronics Forum | Fri Jul 02 17:08:58 EDT 2004 | blnorman
We used to use Alpha paste. Every summer we had solder ball problems when the humidity rose. Time frame sounds like this is something to check in to.
Electronics Forum | Thu Jun 24 14:34:13 EDT 2004 | tjensen
There are many factors that can lead to solder balls. Since you have just recently seen this start to occur, it is obvious something has changed in the product or your process. Since we don't have a lot of details about your process, I would sugges
Electronics Forum | Tue Jul 06 08:10:34 EDT 2004 | yukim
The manufacturer confirmed that it is humidity - the solder paste is too sensible to humidity. Now I tried Koki solder paste with good result. But, it does leave flux residue in good quantity. Does anyone have experience with Koki solder paste?
Electronics Forum | Wed Apr 11 22:05:58 EDT 2001 | davef
OA pastes are more hydroscopic than NC pastes. Hydroscopic. The capacity of a material to absorb and retain moisture from the ambient air. Sometimes this is compounded if you remove paste from the frig and let it warm to room temperature, because
Electronics Forum | Sat Jul 03 02:13:01 EDT 2004 | yukim
The manufacturer says that since this solder paste has synthetic flux (not natural rosin) it is sensible to humidity. Worked with reflow profiles, but no remarkable improvements. We are changing solder paste every 2 hours.
Electronics Forum | Tue Jul 06 10:46:12 EDT 2004 | blnorman
We have now switched to Kester EP256. During our solder paste evaluation, resistance to humidity was one of the selection criteria. We printed multiple boards, then exposed them to 85�F/65% RH. At 30 minutes, 1 hour, 2 hours, and 4 hours exposure
Electronics Forum | Fri Jun 25 09:19:12 EDT 2004 | tjensen
60-70% RH will be a challenge if you are running a water wash solder paste (and could be the reason you are seeing the problems). If you are running a no-clean, humidity should not be an issue. As long as the profile looks OK, I don't think the con
Electronics Forum | Wed Jun 30 10:24:27 EDT 2004 | K
We find keeping the work environment at about 22degC and humidity to about 40-50% is the best way to control the solder balls. Before we took measures we were out of control with solder balls especially in the summer months. We run aqueous solder thr
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