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Date: | Thu, 11 Apr 2019 17:58:45 -0700 |
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Gentlemen-
What the dickens is going on with IPC-A-600 Section 2.9.5? The
"Nonconforming" snapshot at the bottom shows a bit of soldermask chipping
due to the designer neglecting to clear the engraved area for the "V-score"
process. The chipped mask exposes no conductors and does not decrease the
protected distance between any conductors. The edges of the through-hole
pads are already exposed due to the soldermask backoff.
I tried to work through the IPC requirements which should cover this case
and I can't find any other than this explanatory picture book. The only
explanatory statement is that this applies "when the design requires
coverage to the printed board edge." Sounds like an unusual requirement for
this situation, given that a "V-score" makes a sloping, messy edge anyway.
Is the convention that, because this silliness got into the document, if
some lazy layout guy neglects to clear the path for the "V-score", that it
is then presumed that "the design requires coverage to the printed board
edge?" That'd be pretty ridiculous since if the lazy layout guy forgot to
clear the mask, you can be certain they aren't going to bother creating a
special note directing the fabricator to ignore his laziness.
Wayne Thayer
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