If you place high temp tape around the QF, it would prevent the protrusions and also (to some degree) thermally diminish the amount of heat the adjacent capacitors receive.

My 2 cents

David



-----Original Message-----
From:   "TechNet" <[log in to unmask]> on behalf of        "Mary Jane Chism" <[log in to unmask]>
Sent:   Thursday, September 29, 2005 9:20 PM
To:     "[log in to unmask]" <[log in to unmask]>
Subject:        [TN] Solder Protrusions

We are experiencing icicles (solder protrusions) as the results of
rework being performed on a flatpak.  The process is hot air removal of
the flat pak and hand soldering for replacement.  In the process of hand
soldering, the operators are touching some of the surface mount
capacitors around the flat pak causing solder protrusions off of the
solder fillet of the capacitors.
 
In IPC-A-610, it states as long as the solder protrusions do not violate
height requirement and electrical clearance, they would be acceptable.
However, I feel the objective of performing rework is that you only
perform the operation of soldering without putting any thermal stress on
the rest of the components.  
 
I realize this is hard for anyone to actually answer this, but my
question is, if you can answer this, would you:
 
1. Re-address your rework process and also get rid of the icicles?
2. Re-address your rework process but let the icicles go?
3. Don't do the rework?
4. Get different rework operators to perform the rework?
 
Your comments will be very much appreciated.
 
Thanks.
 
Mary Jane Chism
 
 


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