We bake for 4 hours at 125 degrees C.  We must then either vacuum pack
or use within an hour.  This is working wonderfully.  No problems.  We
bulid to Class II.

Thanks,
Kathy Palumbo
> ----------
> From:         BOB HAYNES[SMTP:[log in to unmask]]
> Sent:         Tuesday, February 24, 1998 9:43 AM
> To:   [log in to unmask]
> Subject:      [TN] [ASSY} Prebake
>
> Ladies and Gentlemen,
>
> This issue was the subject of a lively amount of discussion a couple
> of years ago. The question has once again come up in the company I
> work for so thought would get the opinion of others. There does not
> seem to be any exact guidance in any of the IPC publications that I
> am aware of.
>
> When we worked to MIL-C-28809B Par. 3.5.7 left no doubt of what
> to do. One was required to bake at 105 Deg. C for an unspecified
> time to remove absorbed moisture. Also if the time interval between
> baking and soldering was greater than 8 hours you were required to
> rebake.
>
> My company set this unspecified time as  12 hours (overnight) and has
> continued to use the same process even though most of our production
> is now commercial. Also most of the assembly is now surface mount and
> when MIL-C-28809 was written (1988) most assembly was TH.
>
> What are other assembly houses doing baking or not baking?
>
> ################################################################
> TechNet E-Mail Forum provided as a free service by IPC using LISTSERV
> 1.8c
> ################################################################
> To subscribe/unsubscribe, send a message to [log in to unmask] with
> following text in the body:
> To subscribe:   SUBSCRIBE TechNet <your full name>
> To unsubscribe:   SIGNOFF TechNet
> ################################################################
> Please visit IPC web site (http://jefry.ipc.org/forum.htm) for
> additional information.
> For the technical support contact Dmitriy Sklyar at [log in to unmask] or
> 847-509-9700 ext.311
> ################################################################
>

################################################################
TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c
################################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body:
To subscribe:   SUBSCRIBE TechNet <your full name>
To unsubscribe:   SIGNOFF TechNet 
################################################################
Please visit IPC web site (http://jefry.ipc.org/forum.htm) for additional information.
For the technical support contact Dmitriy Sklyar at [log in to unmask] or 847-509-9700 ext.311
################################################################