Assuming you have adequate top and bottom preheating the cause is almost
certainly poor PCB fabrication. You could try baking out the boards before
soldering to see if this has an effect on the incidence/severity. This won't
cure the problem but a change will point to the cause.


Regards

Mike Fenner
Indium Corporation

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Irving Lee
Sent: Thursday, November 30, 2006 4:31 PM
To: [log in to unmask]
Subject: [TN] Solder Voids in Hole barrel after W/S


What are  the critical control factors to avoid solder voids in hole barrel
after W/S ?
We have checked following items , but still have serious solder void problem
.
 1. Good Hole Wall Quality
 2. Good solderability for component tail
 3. Good HASL thickness
 4. No Ionic contamination


Irving Lee

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