Hi Annie - there is very good article on blowholes that you will find
helpful - get a copy of :

"The Harmfulness of Blowholes in PTH Soldered Assemblies" , Colin Lea ,
Circuit World, Vol. 16, No. 4, 1990, pages 23-28.

The article covers blowholes in great depth (pardon the pun :)  ) and lists
several additional references. Good Luck.

Dave Hillman
Rockwell Collins
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annie laberge <[log in to unmask]> on 01/06/99 08:29:29 AM

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Subject:  [TN] pinholes




Good morning everyone

On some of our products, we have pinholes in Through holes solder joints.
We have no idea what is the root cause of these pinholes.
Could the root cause come from the PCB ? And if so, what default in the PCB
could cause this ?

These products are 8 layers PCB, with 4 ground planes which 2 of them are
on outer layers, and 0.093" thick, and the hole diameter is 0.023".

With these products, we had lots of problems.
Fist we had missing solder because of the lack of heat caused by the heat
disssipation of the ground planes.
We optimised our wave parameters to minimize the problem.
Then we had blow holes.   The root cause was humidity in the board.  We
don't have this problem anymore.

Any help would be greatly appreciated, thanks in advance.

A. Laberge
Quality Eng.
Matrox

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