Thanks Leo.
I will add this to my list of things to look at to help us ID the root
cause to the problem.  I don't want to just say "it's the supplier" or
"it's the boards".  It would be nice for us to really understand the
cause.

Thanks again,
Carrie

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Leo Lambert
Sent: Friday, September 10, 2004 3:07 PM
To: [log in to unmask]
Subject: Re: [TN] Blow Holes -- Where the heck does the moisture come
from anyway?

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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