Hi there Tech-Netters!

I have a question concerning the acceptability of some Fab boards.

The board is a backplane, 16 layers, all 2 oz thick, and class 3.

The problem is that some of the annular rings are being pulled out of
alignment at drilling. This leaves cracks all around the annular ring, a gap
behind the annular ring in the laminate and occasionally plating going into
the crack and sometimes around the annular ring. The hole size where this
takes place is 0.020" with a 0.040" pad by design, but built with 36-37 mils
pads in reality.

There has been a few instances where the annular ring has been pulled out
completely.

Now I know this is in ZONE "A" of the evaluation coupon, I also know that
cracks in these area are acceptable per IPC-6012A class 3. But this refers
to laminate cracks and voids, not whole annular ring being pulled out of
place completely.

Steve Gregory has agreed to post a picture on his amazing site at:
http://stevezeva.homestead.com/index.html

(This may not be today, he's still on vacation, but most likely tomorrow,
July 9th.)

What I would like, if you please, is your opinion on the acceptability of
these boards. Don't forget these are class 3 backplanes.

Thank you all and thanks Steve for taking this time off your vacation,

Alain Savard
QA - PCB
CAE Inc.

---------------------------------------------------------------------------------
Technet Mail List provided as a free service by IPC using LISTSERV 1.8d
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/html/forum.htm for additional
information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315
---------------------------------------------------------------------------------