MILPRF50884F
APPENDIX A
c.
Resistance to soldering heat (solder float thermal stress) (see A.3.7.6.2).
(1) Types 1 and 5: The test specimen shall be test coupon "B". The number of sample units to be tested
and inspected shall be based on a statistical sample of panels in the lot in accordance with appendix C,
table CI, series L. The samples for as-received condition and resistance to soldering heat testing shall
be selected from different panels.
(2) Type 2: The test specimen shall be test coupon "B". The number of sample units to be tested and
microsection inspected shall be based on a statistical sample of panels in the lot in accordance with
(3) Types 3 and 4: The test specimen shall be test coupon "B" or "AB-R". A minimum of one test
specimen for each panel shall be tested and microsection inspected. Additional sample units shall be
microsectioned based on a statistical sample of panels in the lot in accordance with appendix C,
table CI, series J. For designs with blind or buried vias, at least one additional test coupon "B" for
each panel shall be subjected to the resistance to soldering heat test in accordance with A.4.8.6.2 and
inspected to the requirements of A.3.7.2 for each additional copper plating process used (see A.6.12 for
additional guidance).
d.
Registration.
(1) Method I (types 1, 2, and 5 only): When method I is used, registration shall be evaluated using any
combination of "A" test coupons taken from diagonal corners of the inspection panel.
(2) Method II (types 3 or 4 only): When method II is used, registration shall be evaluated using any
combination of two microsectioned test specimens taken from diagonal corners of the inspection panel.
Both sample units shall have been microsectioned in the vertical plane with one sample unit
representing the panel's length (X) direction and the other representing the panel's width (Y) direction.
Test coupons from the as-received condition (see A.3.7.2.1), resistance to soldering heat (see
A.3.7.6.2) or when available, hole solderability (see A.3.7.4.9.1) verifications may be used.
(3) Method III: When method III is to be used, the number of sample units needed for verifying registration
shall be documented in the qualifying activity approved alternate test plan (see C.5.2.2).
e.
Copper plating voids (see A.3.6.4.4). When a single plating void that is within the acceptable limits of
A.3.6.4.4 is present in a microsection or set of microsections representing an inspection panel, a referee
sample unit from that panel shall be microsectioned and inspected for copper plating voids. The referee
microsection shall be performed using an "A" or "B" test coupon from the opposite corner of the suspect
panel. If the referee microsection has no plating voids, then that panel is acceptable, however, if a plating
void is present in the referee microsection, that panel of printed wiring boards shall be rejected. Any plated-
through hole in the microsection failing the plating void criteria specified in A.3.6.4.4 subparagraphs a, b, or
c, shall be cause for the entire inspection panel of printed wiring boards associated with the microsection to
be rejected.
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