Yes, Cara, if the board has not been properly cleaned and baked prior to
assembly you will get blow holes! Check the holes, (assume PTH) with a good
high power stereo microscope, for foreign material. Taping a small ball
bearing to the backside of the board and viewing into the topside of the
hole will give you a "fish eye" view of the entire barrel. If you find
"crud" in the holes determine what the material is and clean it out. (After
solvent cleaning blow dry the holes with dry Nitrogen.) It works for us :-)

Ron Dieselberg
BAE SYSTEMS
Cincinnati Electronics Corp.

-----Original Message-----
From: Cara.Startek [mailto:[log in to unmask]]
Sent: Wednesday, August 09, 2000 14:52
To: [log in to unmask]
Subject: [TN] Blow Holes


I'm having a problem with blow holes occurring in a thick board that I'm
running on a wave solder machine.  As a test I am going to bake the boards
for 24hrs to remove moisture from the board and eliminate this as a cause of
the problem.  Is there any thing else that cold be causing blow holes?

Cara Startek

Process Engineering
http://www.leitch.com

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