Electronics Forum | Mon May 07 17:59:07 EDT 2001 | davef
One thing I forgot to add about the globs of solder on your bottom side SMT components after wave soldering: The excess solder is likely reducing the reliability of these components, because of the difference in CTE betweeen the ceramic base on the
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 | Thu Jul 17 15:12:18 EDT 2008 | slthomas
To quote a regular here, "Are you sure your washer is set up correctly?" :P He's a WS junkie. This is a really common problem and is discussed here often. Mid chip solder balls (solder beads) are almost always the result of too much paste being dep
Electronics Forum | Thu Jun 24 07:55:08 EDT 2004 | cyber_wolf
What manufacturer of solder paste are you using? Just curious.
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 | 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 | Mon Jun 11 22:00:19 EDT 2001 | davef
IPC-A-610 uses words to the effect that it�s a Class 2 process indicator, if either: * Entrapped or encapsulated solder balls that are within 0.13 mm [0.00512 in] of lands or connectors, OR * Entrapped or encapsulated solder balls exceed 0.13mm [0.00
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 | Sat Jul 03 08:52:19 EDT 2004 | davef
Q1: What's the difference between static and dynamic viscosities? A1: Static viscosity is the viscosity of the solder paste as it is dispensed off of a tube or syringe onto a screen printer. Dynamic viscosity gives the variation in the thixotropic b
Electronics Forum | Thu Jul 17 20:46:55 EDT 2008 | davef
Which type? * Solder beads (mid-chip solder balls, attached to the waste line of your chip caps and resistors) This is more paste volume related. * Solder balls that tend to be more randomly scattered (as in spattered)? This tends to be more profile
