Hi Dale,
From your posting it is not clear whether your client wants to reject the lot
because "the coupons on the outer edge of the board were greater than 0.5 inch
from the active area of the board as specified by IPC 275" or because there is
"a random etchback problem" in the boards. The impression given is that it is
the former. If that is the case than this is pretty 'legalistic' and not based
on technichal insight. If you look at Figure 7-1 of IPC-D-275 you will see
that the coupon location is given as "0.250"/0.500" TYP", but the language in
Section 7.3.1 describes this location with a "shall'—which is interpreted as
"mandatory" as per Section 1.4, unless "sufficient data is supplied to justify
the exception". If the X-sections from inside the PCB and the coupons show the
same, that should constitute "sufficient data." Since you have X-sections of
some of the real PCBs, it is this information that should be decisive. You do
not say what you mean by " a random etchback problem", so it is not clear
wehther based on these sections the lot should be rejected.

Werner Engelmaier
Engelmaier Associates, L.C.
Electronic Packaging, Interconnection and Reliability Consulting
7 Jasmine Run
Ormond Beach, FL  32174  USA
Phone: 904-437-8747, Fax: 904-437-8737
E-mail: [log in to unmask]


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