Hi TechNet!
     
     Are the solder skips location dependent or always near specific types 
     of other components on the assembly? You may be getting shadowing ( an 
     alteration of the solder wave flow) of your components from other 
     components or structures on the assembly. You could also try checking 
     your nitrogen environment - a "cleaner" nitrogen blanket (i.e. less oxygen 
ppm levels) will lower the solder surface tension and allow for additional 
wetting. Note - really low surface tension can give you defects too!

Dave Hillman
Rockwell Collins
[log in to unmask]

______________________________ Reply Separator _________________________________
Subject: Assy: Solder Skip
Author:  [log in to unmask] at ccmgw1
Date:    1/16/97 9:59 AM


Hi Technetters,
     
I am wandering anyone could suggest ways to get rid of solder skips.
     
We have a lot of solder skip on the Tant capacitor, case size type A 
and B, but don't have any problem with the rest of the chip components 
and SOICs. The pad size for the Tant Cap id pretty small, only allow 
very little for space for the chip wave to be able to solder to the 
terminations.
     
Any ideas how to fix it..We are running no-clean using a full-blow  nitrogen 
tunnel wave-solder machine.
     
     
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