K - I - S - S (excuse the last "S"),
except for vias, continue to call out plated holes with a
+/-.003 tolerance. All Fab houses are accustomed to this
spec. For vias the tolerance of +.003/- nominal works fine.
Fab houses run DRC's that will detect drilled hole to trace
spacing violations and avoid "punching out a trace".

Thank you,
Eddie Rocha



Hello,

I am a designer (...wait! wait! Don't throw anything
yet!...) and we are
discussing hole and drill callouts in standard high Tg FR4
material on the
design side and I'd like to hear from ya'll.

I specify a hole of .020 and a tolerance of plus .003 and
minus .003
(inches), along with a note stating ALL HOLE SIZES ARE
FINISHED.  Now I
don't care how the hole is made: drill, laser, plasma,
teeth.  As long as
the hole is as I specify, I figure the board house knows
what their best
method would be.  And I request electrical test before I
see the boards on
my loading dock.

A well-respected colleague says that he specifies the drill
hole and
tolerance before finish.  He maintains the fab house could
drill a via hole
at up to .020 and plate it down to .010, and that it will
punch out any
traces as the hole is made.  Further, he says that
electrical test isn't
enough and when the board is stuffed and under full load
that the heat could
cause further problems.

Make sense?

How do you prefer to see the holes called out?

Regards,

Bob Wilson
Electro-Mechanical Designer
SpectraSensors, Inc.
972 N. Amelia Ave.
San Dimas, CA 91773
800-619-2831 x239
www.spectrasensors.com

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

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