Hi Frank...

Well... if the board had been laid out properly.... you would not see any
power or ground where there was a beveled edge...
The designer of the board should make a minimum clearance around the entire
board outline to allow a gap between the power/gnd planes and the board
edge... in the area where there is to be a beveled edge it may need to be a
greater gap than the rest of the perimeter...
Most of the board houses I have talked with like to see a .050 min. gap
between the edge of the board and the internal planes or circuits. Or any
circuits for that matter... top or bottom. this allows a good adhesion of
the laminate and prevents shorting between the layers, if the board comes
into edge contact with any conductive medium. And it's good design
practice... too. Of course, there are exceptions... edge contacts need to
come to the edge... etc...  but in the illustration you sent below, these
are internal planes and should not be exposed by the chamfering process.

Bill Brooks
Senior PCB Designer - [log in to unmask]
Zoneworx, Inc.
40925 County Center Drive, STE 200
Temecula, CA 92591
http://www.zoneworx.com
Tel: (909) 296-1226 x 1037
Co-Director / Education Officer / Webmaster
for the San Diego Chapter of the IPC Designers Council
http://www.ipc.org/SanDiego/index.html
http://home.fda.net/bbrooks/pca/


-----Original Message-----
From: Franklin D Asbell [mailto:[log in to unmask]]
Sent: Wednesday, October 05, 1988 9:36 AM
To: [log in to unmask]
Subject: [TN] Exposed power-ground plane


I need some input from all of you...

What specification provides criteria for power-ground planes being
exposed due the bevel process, or actually exposed planes for any
reason?

Or does anyone know the specific criteria, dimension, tolerance, etc for
this condition.

----------
------------\-   < exposed power layer
------------/-   < exposed ground layer
----------

Thanks,

Franklin D Asbell

----------------------------------------------------------------------------
-----
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
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
----------------------------------------------------------------------------
-----

---------------------------------------------------------------------------------
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
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
---------------------------------------------------------------------------------