MILPRF50884F
APPENDIX A
A.3.5.2.2.1 Coverage. The conductor finish plating or coating shall cover the basis metal of the conductive
pattern. Coverage of a conductor by solder does not apply to the vertical conductor edges. There shall be no
evidence of any lifting or separation of conductor finish plating or coating from the surface of the conductive pattern.
A.3.5.2.2.1.1 Dewetting. For tin alloys, reflowed tinlead, or solder coated surfaces, a maximum of five percent of
dewetting is permitted on any conductive surface where a solder connection will be required. Dewetting on
conductors, ground, or voltage planes not used for solder connections shall meet the requirements of JSTD003.
A.3.5.2.2.1.2 Nonwetting. For tin alloys, reflowed tinlead, or solder coated surfaces, nonwetting is not permitted
on any conductive surface where a solder connection will be required. Absence of solder on the vertical sides of
lands shall be acceptable.
A.3.5.2.2.2 Conductor finish plating and coating voids in plated-through holes. The conductor finish plating and
coating shall not have voids in plated-through holes that exceed the following limits:
a.
No more than one final finish void in any plated-through hole.
b.
Not more than 5 percent of the plated-through holes shall have conductor finish voids.
c.
Any conductor finish void present is not more than 5 percent of the plated-through holes length.
d.
Any conductor finish void present is less than 90 degrees of the circumference of the plated-through hole.
A.3.5.2.2.3 Edge board contacts. Unless otherwise specified, these requirements apply to the critical contact area.
The critical contact area for edge board contacts shall be as specified.
a.
Defects or surface imperfections in the edge board contact finish shall not expose base metal in critical
contact area.
b.
There shall be no nodules or metal bumps in the edge board contact finish in the critical contact area.
c.
Pits, dents, or depressions in the edge board contact finish shall not exceed .0059 inch (0.15 mm) in their
longest dimension. There shall be no more than three occurrences for each edge board contact, and no
more than 30 percent of the contacts shall be affected.
A.3.5.2.2.4 Plating junctions (typical of edge board contacts). There shall be no exposed copper in the junction of
metallic platings or coatings. An overlap of metallic platings or coatings shall be acceptable if less than .032 inch (0.8
mm) in length. When both solder coating and gold plating are present at a plating junction, a discolored or gray-black
area at that plating overlap zone shall be acceptable.
A.3.5.2.2.5 Solder mask. For designs using solder mask over bare conductors, it shall be acceptable to have up to
.010 inch (0.25 mm) of exposed base metal at the interface between the solder mask and the basis metal conductor
finish.
A.3.5.2.2.6 Whiskers. There shall be no whiskers of solder or other platings on the surface of the conductive
pattern.
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