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October 1999

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Subject:
From:
Alberto Callo <[log in to unmask]>
Reply To:
TechNet E-Mail Forum.
Date:
Thu, 14 Oct 1999 09:12:31 -0700
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We bake our populated boards prior to conformal coating for about 2
hours at 60 Celsius.  We've found that's all is needed to get the
moisture out off the board.  However, I wouldn't mind seeing your
results Eric.

Eric Kalgren wrote:
>
> Is everyone baking their boards with components stuffed or are you all baking bare PCBs?  We currently bake stuffed PCAs for 6 hrs in a 150F vaccuum oven.  If it sounds like a long time, well, it probably is.  We have some experiments planned to see how long is long enough.  If anyone wants results, contact me directly.  If anyone has suggestions as to how long should be long enough, please don't hesitate to let me know [as if anyone out there would!! :-)  ]
>
> Eric Kalgren
> BFGoodrich Aerospace
> Data Systems Division
> [log in to unmask]
> (505) 938-5139
>
> >>> Werner  Engelmaier <[log in to unmask]> 10/14/99 07:57AM >>>
> Hi Steve,
> Your root cause for the delaminations is moisture absorption, that is why
> baking works. Boards subjected to high air humidity for a sufficient time
> will fully saturate (at local ambient equilibrium). The time necessary will
> primarily depend on the polymer involved and on the location of the P/G
> planes.
>
> Werner Engelmaier
> Engelmaier Associates, L.C.
> Electronic Packaging, Interconnection and Reliability Consulting
> 7 Jasmine Run
> Ormond Beach, FL  32174  USA
> Phone: 904-437-8747, Fax: 904-437-8737
> E-mail: [log in to unmask], Website: www.engelmaier.com
>
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