MILPRF50884F
APPENDIX A
A.3.5.2.3 Conductor pattern imperfections (see figures F2 and F3). The conductor pattern shall contain no
cracks, splits or tears. Unless otherwise specified, any combination of edge roughness, nicks, pinholes, cuts, or
scratches exposing the base material shall not reduce non-critical conductors width by more than 20 percent of its
minimum specified width. There shall be no occurrence of the 20 percent width reductions greater than .50 inch
(12.70 mm) or 10 percent of a signal conductor length, whichever is less.
A.3.5.2.3.1 Cuts and scratches. A cut or scratch of any length or width is permissible on ground or voltage planes,
provided the dielectric is not exposed. Cuts and scratches on non-critical conductors may be of any length, but no
deeper than 20 percent of the total conductor thickness.
A.3.5.2.3.2 Dents. A dent of any length or width on ground planes shall be acceptable provided the clad surface is
not torn. Dents on conductive patterns may be of any length, but no deeper than .0005 inch (0.013 mm).
A.3.5.2.3.3 Pinholes. Pinholes in ground or voltage planes in non-critical areas shall be acceptable provided they
have no single diameter greater than .040 inch (1.0 mm) and do not exceed four for each 1.0 inch (25.4 mm)
diameter. Pinholes in a conductive pattern shall be acceptable, provided they do not reduce the width of a conductive
pattern by 10 percent and do not exceed one for each 1.0 inch (25.4 mm ) of a conductor length.
A.3.5.2.3.4 Pits. Pits in ground or voltage planes shall be acceptable provided they do not exceed 25 percent of
the surface area. Any pit in the conductive pattern is acceptable provided the outline dimension does not exceed 10
percent of the conductor width, and there is no more than one pit for each 1.0 inch (25.4 mm) of the conductor length.
A.3.5.2.3.5 Superfluous metal. Unless otherwise specified, small particles of metal, such as residual copper or
subsequent plating after etching, which remain affixed to areas that are intended to be free of conductive material
shall be acceptable providing the following conditions are met:
a.
The superfluous metal is no closer than .25 inch (6.4 mm) to any conductor.
b.
The superfluous metal is smaller than .005 inch (0.13 mm) at their greatest diameter.
A.3.5.2.4 Conductor spacing and width.
A.3.5.2.4.1 Conductor spacing. The conductor spacing shall be as specified (see A.3.1.1). The minimum edge
spacing (the spacing between the edge of the printed wiring board and conductors) shall be as specified. Unless
otherwise specified, if no conductor spacing tolerance is specified, a reduction in the conductor spacing of 10 percent
above the specified spacing, due to isolated defects or misregistration, shall be considered acceptable.
A.3.5.2.4.2 Conductor width. The conductor width(s) shall be as specified (see A.3.1.1). Allowable reduction in
the conductor width, due to isolated defects or misregistration, shall be in accordance with A.3.5.2.3.
A.3.5.2.5 Lands for component mounting. The lands to be used for component mounting shall be as specified.
Imperfections on component hole lands, surface mount lands, or wire bond pads shall be acceptable provided they
do not exceed the defect allowance requirements specified herein.
A.3.5.2.5.1 Component hole lands (external annular ring (see figures F4 and F5). The minimum external
annular ring shall be as specified (see A.3.1.1). If not specified on the applicable master drawing, the minimum
external annular ring shall not be less than the value specified in the IPC's 2220 series of documents for the design of
flexible or rigid-flex printed wiring boards. Unless otherwise specified, the external annular ring may have, in isolated
areas, a 20 percent reduction of the minimum external annular ring specified, due to defects such as access hole
(coverlayer or stiffener) misregistration, dents, pinholes, pits, nicks, and extruded adhesive onto the land. No more
than 20 percent of the annular ring circumference (72 degrees) may be affected. Unless otherwise specified, plated-
through holes identified as vias can have a maximum of 90 degrees of hole breakout if the breakout does not occur at
the conductor to land intersection.
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