MILPRF55110G
APPENDIX A
A.4.8
A.4.8 Methods of inspection. The following identified tests and test methods are used to assure printed wiring
board integrity within typical operating conditions. Alternate commercial or industry standard test methods may be
allowed; however, if an alternate method is to be used, the qualifying activity shall be notified prior to the performance
of the test. The following verification test methods described herein are proven methods and shall be the referee
method in case of dispute.
A.4.8.1
A.4.8.1 Acceptability inspection. The visual and dimensional features of the printed wiring board test specimen
shall be inspected using test method numbers 2.2.1 and 2.2.2 of IPC-TM-650, as applicable. Referee inspection
needed to confirm a suspected defect of the test specimen features shall be accomplished at a magnification of up to
30X, as applicable to confirm the suspected defect.
A.4.8.1.1
A.4.8.1.1 Annular ring, external (see A.3.5.2.1). The measurement of the annular ring on external layers is from
the inside surface (within the hole) of the plated hole or unsupported hole to the outer edge of the annular ring on the
surface of the printed wiring board. See figure A1 for illustration.
A.4.8.1.2
A.4.8.1.2 Overall printed board thickness (see A.3.5.3). Unless otherwise specified, the overall printed board
thickness measurement shall be inspected by any micrometer or by microsection in accordance with A.4.8.2.
A.4.8.1.2.1
A.4.8.1.2.1 With edge-board contacts. Printed boards with edge-board contacts shall have the overall thickness
measured across the board on the final finish plated surfaces of opposite contacts.
A.4.8.1.2.2
A.4.8.1.2.2 Without edge-board contacts. Printed boards without edge-board contacts shall have the overall
thickness measured across the board from plated copper surface to plated copper surface not including the final finish
plating.
A.4.8.1.3
A.4.8.1.3 Registration (method I) (types 1 and 2) (see A.3.5.6). Registration of type 1 and type 2 printed wiring
boards shall be satisfied if the outer layers meet the external annular ring (see A.3.1.1 and A.3.5.2.1) and hole pattern
A.4.8.1.4
A.4.8.1.4 Solder resist thickness (see A.3.5.7). Solder resist thickness shall be inspected by any micrometer or by
microsection in accordance with A.4.8.2.
A.4.8.1.5
A.4.8.1.5 Workmanship. The printed board specimen shall be inspected in accordance with test method number
2.1.8 of IPC-TM-650, except that the magnification shall be 1.75x (3 diopters), minimum.
A.4.8.2
A.4.8.2 Microsection inspection.
A.4.8.2.1
A.4.8.2.1 Microsection preparation. Microsection preparation shall be accomplished by using methods in
accordance with either test method numbers 2.1.1 or 2.1.1.2 of IPC-TM-650. Automatic microsectioning techniques
may be used in lieu of test methods 2.1.1 or 2.1.1.2 of IPC-TM-650 (see A.6.10). The following details shall apply:
a.
Number of holes per specimen. A minimum of at least three plated holes cross sectioned vertically shall be
made for each test specimen required. Each side of the three plated holes shall be viewed independently.
b.
Accuracy. All three plated holes of each test specimen shall be sectioned, ground, and polished to within ±10
percent of the center of the drilled diameter of the hole.
c.
Pre microetch evaluations. The specimens shall be evaluated for plating separations, superfulous copper, and
wicking prior to microetching (see A.6.11).
d.
When more than two test specimens are contained in a mount (couponstacking or gang mounting), the
following shall apply:
(1) The test specimens shall not be in direct contact any other specimen in the mount. The recommended
minimum distance between test specimens in a mount is .010 inch (0.025 mm).
(2) The traceability requirements of A.3.9.1 shall apply.
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