Graham,

In my last job we dealt with several types of boards containing Polyimide,
both rigid and rigid-flex constructions.  Our board vendor for these
indicated it was essential to bake these prior to processing due to the
increased propensity of this material to absorb moisture.  Our standard bake
for these was 4 hours @ 125 C, which was the vendors recommendation.

Rick Thompson

Sr. SMT Process Engineer
SMTEK International, Inc.
+1 (805) 532-2800
[log in to unmask]


===== Original Message from [log in to unmask] (TechNet E-Mail Forum.) at
10/23/02 11:06 am
>Good day Technet!
>Another PWB question for the 'net today.
>
>If you have a board made with Polyimide material ( IPC 4101/40) would you
>bake it prior to processing?  We gave up baking FR-4 boards years ago with
>no impact, but there is some debate as to Polyimide.
>
>Please note, I'm not talking about flex prints, I understand they need to
>be baked before processing due to delamination issues.
>
>Thanks!
>
>
>regards,
>
>Graham Collins
>Process Engineer,
>Northrop Grumman Canada Corporation
>Halifax
>(902) 873-2000 ext 6215
>
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