MILPRF50884F
APPENDIX A
A.3.6.7 Hole wall deficiencies (see figures G20 and G21). Nodules, plating folds, or plated glass fibers that
project into the copper plating shall be acceptable provided that the hole diameter and the hole wall copper thickness
are not reduced below the limits specified (see A.3.1.1). Isolated areas of reduced copper thickness due to glass
fiber protrusions shall meet the minimum thickness requirements specified, when measured from the end of the
protrusion to the edge of the hole plating.
A.3.6.8 Metallic cracks (see figure G22). There shall be no cracks in the internal layer conductive foils, platings,
or coatings. Cracks in outer layer metal foil shall be acceptable if they do not propagate into the plated copper.
Cracks shall not be acceptable in the copper plating.
A.3.6.9 Nail-heading. Nail-heading of conductors shall not exceed 1.5 times the copper foil thickness.
A.3.7 Inspection requirements. The detailed requirements contained in this section, although determined by
examination of sample printed wiring boards or test coupons, apply to all deliverable printed wiring boards.
A.3.7.1 External visual and dimensional acceptability (of printed wiring boards). When examined as specified in
A.4.8.1, the printed wiring boards shall be in accordance with the requirements specified in A.3.1.1 (master drawing),
A.3.4 (material), A.3.5 (visual and dimensional), A.3.8 (marking), A.3.10 (repair), and A.3.12 (workmanship).
A.3.7.2 Destructive physical analysis (DPA) by metallographic evaluation of printed wiring board test specimens.
When printed wiring board test specimens (finished printed wiring boards, supporting test coupons, or qualification
test specimens) are microsectioned and examined as specified in A.4.8.2, the requirements specified in A.3.1.1,
A.3.7.2.1 Non-stressed specimens (as received condition). After meeting the requirements of A.3.8 and A.3.12
when inspected in accordance with A.4.8.1, the non-stressed (as received) printed wiring board test specimen shall
be microsectioned and inspected in accordance with A.4.8.2 and the requirements of A.3.1.1, A.3.3, and A.3.6 shall
be met.
A.3.7.2.2 Registration, internal.
A.3.7.2.2.1 By microsection (method II). Unless otherwise specified (see A.3.1.1), when inspected as specified in
A.4.8.2.2, the layer-to-layer pattern misregistration shall not reduce the minimum annular ring below the limits
specified (see A.3.1.1).
A.3.7.2.2.2 By registration test coupons (method III) (optional). Registration test coupons may have been
designed into the printed wiring board by the design activity, or may be added to the panel by the manufacturer to
enhance testability (see A.4.8.2.4.2 and appendix H). To be usable for acceptance purposes, registration test
coupons shall relate the actual grid location of each circuitry layer to all other circuitry layers and to the hole pattern
accuracy required (see A.3.5.4) in each printed wiring board.
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