Out of curiosity, where are these requirements stated?
Rick
>-----Original Message-----
>From: Dewey Whittaker [SMTP:[log in to unmask]]
>Sent: Tuesday, March 21, 2000 3:09 PM
>To: [log in to unmask]
>Subject: Re: [TN] Baking FR4 boards
>
>Alain Savard wrote:
>
>> Isn't the 72 hours before bake a requirement for polyimide instead of FR4?
>>
>> Alain Savard, B.Sc.
>> Chemical Process Analyst
>> CAE Electronics Ltd.
>> e-mail: [log in to unmask]
>>
>> -----Original Message-----
>> From: Dewey Whittaker
>> 1. Typically, for multi-layer (6-8 layers), FR4, SMT boards stored in an
>>air
>>
>> conditioned environment at about 50+/- 10% RH, how many months would you
>> allow
>> to pass before you would recommend baking them prior to reflow?
>> 2. What would be your bake cycle?
>> Thanks,
>> Charlie B.
>> ####################################
>> Without knowing any other variables and being conservative,72 hours is your
>> window for the Aerospace Industry.
>> Dewey
>> --
>> Dewey Whittaker
>>
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>
>If it were Polyimide,it would be 24 hours(realistically 8 hours).Through
>testing and proper storage conditions,each design could have a much greater
>processing window.4 hours at 100 degrees C. is the bake.
>Dewey
>
>--
>Dewey Whittaker
>Honeywell -- Air Transport Systems Division
>US Mail: P.O. Box 21111 MS: M16A2 Phoenix AZ 85036
>Phone: +1 602 436 436-2766
>NSFnet: [log in to unmask]
>
>
>
><!doctype html public "-//w3c//dtd html 4.0 transitional//en">
><html>
>Alain Savard wrote:
><blockquote TYPE=CITE>Isn't the 72 hours before bake a requirement for
>polyimide instead of FR4?
><p>Alain Savard, B.Sc.
><br>Chemical Process Analyst
><br>CAE Electronics Ltd.
><br>e-mail: [log in to unmask]
><p>-----Original Message-----
><br>From: Dewey Whittaker
><br>1. Typically, for multi-layer (6-8 layers), FR4, SMT boards stored
>in an air
><p>conditioned environment at about 50+/- 10% RH, how many months would
>you
><br>allow
><br>to pass before you would recommend baking them prior to reflow?
><br>2. What would be your bake cycle?
><br>Thanks,
><br>Charlie B.
><br>####################################
><br>Without knowing any other variables and being conservative,72 hours
>is your
><br>window for the Aerospace Industry.
><br>Dewey
><br>--
><br>Dewey Whittaker
><p>##############################################################
><br>TechNet Mail List provided as a free service by IPC using LISTSERV
>1.8c
><br>##############################################################
><br>To subscribe/unsubscribe, send a message to [log in to unmask] with
>following
>text in
><br>the body:
><br>To subscribe: SUBSCRIBE TECHNET <your full name>
><br>To unsubscribe: SIGNOFF TECHNET
><br>##############################################################
><br>Please visit IPC web site (<a
>href="http://www.ipc.org/html/forum.htm">http://www.ipc.org/html/forum.htm</a
>>)
>for additional
><br>information.
><br>If you need assistance - contact Keach Sasamori at [log in to unmask] or
><br>847-509-9700 ext.5315
><br>##############################################################</blockquot
>e>
>If it were Polyimide,it would be 24 hours(realistically 8 hours).Through
>testing and proper storage conditions,each design could have a much greater
>processing window.4 hours at 100 degrees C. is the bake.
><br>Dewey
><pre>--
>Dewey Whittaker
>Honeywell -- Air Transport Systems Division
>US Mail: P.O. Box 21111 MS: M16A2 Phoenix AZ 85036
>Phone: +1 602 436 436-2766
>NSFnet: [log in to unmask]</pre>
> </html>
>
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