Hi Ray - your bakeout of 4 hours @ 70C would remove a very, very small
amount of water. Is the success you have experienced due to this  bakeout
procedure possibly removing some other volatile material that was causing
defects? Were the boards you were baking flex or rigid-flex?

Dave Hillman
Rockwell Collins
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[log in to unmask] on 02/27/98 06:16:53 PM

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cc:    (bcc: David D Hillman/CedarRapids/Collins/Rockwell)
Subject:  Re: [TN] [ASSY} Prebake -Reply




Ladies and Gentlemen,
It's true that specs. are vague on specifying bakeout times and
temperatures.
When ever I  do Solder Training on TH, I do a low temp. backout at 70 deg.C
for 4 hours,  this has been very sucessfull with me, bit I think the
bakeout should depend on
many factors relating to how long they have been in stock, stock room temp
and humidity to name a few,
I hope of some assistance to you.
Ray Lockshier
Independent Contractor for solder training, problem solving, seminard, ect.
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