Hi Carrie:

I'll give it a shot from my end.

1. Poor Barrels, voids in the barrel, plating solutions behind or between
the pth plating and the laminate. We had multiple problems with this when I
was with DEC. Forces one to really pay attention to the board suppliers and
get plenty of microsections.

2. VOC free flux and other types of fluxes especially water soluble fluxes.
As the flux stays in the fluxer, the old days with foam, this was a problem.
The preheat would not dry out the fluxes enough and the water would vaporize
going over the wave. This not cause blow holes but solder balls all over the
bottom of the board.

3. Can hole way quality play a part, YES YES YES YES.

I expect more comments will add to this list.

Leo

-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of Morse, Carrie
Sent: Friday, September 10, 2004 2:33 PM
To: [log in to unmask]
Subject: [TN] Blow Holes -- Where the heck does the moisture come from
anyway?


Just wondering a few things here at 2:30 on Friday Afternoon:

1.  What else causes Blow Holes at wave on TH comps?  Is it primarily
moisture?
2.  Where does the moisture come from?
3.  Are certain board materials more likely to sponge up the moisture in
the air?
4.  Can hole wall quality play a part in contributing to blow holes?

-Carrie

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