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Date: | Tue, 25 Jun 2002 09:09:21 -0500 |
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(hey Scott, long time no see.... So you're back to using "NVISION"
mailboxes, eh?)
I don't know if you've received other responses because I'm in digest
mode, but from my experience silkscreen is notoriously inaccurate, and
shouldn't be used for critical alignment.
I would put small copper targets or something, because they can't be
"misregistered" with the other copper features on the surface layer.
Board marking is covered in IPC-A-600, but it is only regarding legibility,
not registration. As a general rule I wouldn't trust silkscreen to be more
accurate than +/-10mils, but that is just me talking.
nice to "see" you again, good luck
Jack Olson
Caterpillar, Inc.
Automatic digest processor <[log in to unmask]>@ipc.org>
25Jun2002 12:00 AM
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Date: Mon, 24 Jun 2002 17:06:06 -0700
From: Scott Lefebvre <[log in to unmask]>
Subject: IPC spec on silkscreen alignment.
Is there a IPC spec on silkscreen alignment I could not find one. I have a
component outline that is used for a LLP package to confirm alignment on
the board. Do to the fact this component has not leads it is important to
assure it is properly align to footprint. I have found that the silkscreen
is off .003" in one direction and .011" in the other. The CELL is correct
and I know it's not the data being sent to the board manufacture. Any help
in this matter would be appreciated.
Scott L
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