Probably been discussed to the hilt, but here goes...

Hot air level 4-layer bare PCB, successfully assembled 8-months ago, excess
bare board stock sits on a shelf without any environmental controls for 8
months.  Overstock included with recent batch 8-months later, signs of
significant delamination only on PCBs from that lot after processing through
vapor phase process.

1. Can the board absorb enough moisture during that time to have total
delamination?
I say yes, would like a hail of agreement to support my case.


2. What specific to the process increases a PCBs propensity to delaminate at
assembly?


3. Is there specific IPC directives to pre-bake before assembly?  I have
seen strong recommendations for flex, per the recent discussions, but only
general recommendations otherwise.

Cheers,

Chad

---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 1.8e
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest
Search the archives of previous posts at: http://listserv.ipc.org/archives
Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815
-----------------------------------------------------