MIL-PRF-31032/1B
3.7.3 Chemical requirements.
3.7.3.1 Cleanliness. When printed board test specimens are tested in accordance with 4.7.3.1, the levels of
cleanliness shall be in accordance with the requirements of 3.7.3.1.1 or 3.7.3.1.2, as applicable.
3.7.3.1.1 Prior to the application of solder resist. Unless otherwise specified, prior to the application of solder
resist, the level of ionic contamination shall not exceed 1.56 micrograms/square centimeter (10.06 micrograms/square
inch).
3.7.3.1.2 Completed printed boards (when specified, see 3.1 and 6.2.1.a). The levels of cleanliness for completed
printed boards shall be as specified.
3.7.3.2 Copper plating characteristics.
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3.7.3.2.1 Elongation. When copper plating is tested in accordance with 4.7.3.2, the elongation shall be 12 percent
minimum.
3.7.3.2.2 Tensile strength. When copper plating is tested in accordance with 4.7.3.3, the tensile strength shall be
248 MPa (36,000 psi) minimum.
3.7.4 Physical requirements.
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3.7.4.1 Adhesion, marking. After marking is tested in accordance with 4.7.4.1, any specified markings which are
missing in whole or in part, faded, shifted (dislodged), or smeared to the extent that it is no longer legible shall
constitute failure. A slight change in the color of ink or paint markings after the test shall be acceptable.
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3.7.4.2 Adhesion, plating. When tested as specified in 4.7.4.2, there shall be no part of the conductor pattern or
copper plating protective finish (coating or plating) removed from the printed board test specimen except for those
related to outgrowth, overhang, or slivers.
3.7.4.3 Adhesion, solder resist (when applicable). When tested as specified in 4.7.4.3, the maximum percentage
of cured solder resist lifted from the surface of the base material, conductors, and lands of the coated printed board
test specimen shall not exceed the following limits:
a.
Bare copper or base material: 0 percent.
b.
Non-melting metals (e.g., gold or nickel plating): 5 percent.
c.
Melting metals (e.g., tin-lead plating, solder coating, indium, bismuth, etc.): 10 percent.
3.7.4.4 Bow and twist. When printed boards are tested as specified in 4.7.4.4, the maximum limit for bow and twist
shall be as specified.
3.7.4.5 Rework simulation. After undergoing the test specified in 4.7.4.5, the printed board test specimens shall be
microsectioned and inspected in accordance with 4.7.2 and the requirements specified in 3.6 shall be met.
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3.7.4.6 Solderability (see 6.2.1.b). When required by the procurement documentation, accelerated conditioning for
coating durability shall be in accordance with J-STD-003. The default category of coating durability of J-STD-003 is
category 2.
3.7.4.6.1 Hole solderability. After undergoing the test specified in 4.7.4.6, the printed board test specimen shall
conform to the class 3 acceptance criteria specified in J-STD-003.
3.7.4.6.2 Surface solderability. After undergoing the test specified in 4.7.4.6, the printed board test specimen shall
conform to the class 3 acceptance criteria specified in J-STD-003.
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