MIL-PRF-22710H
3.2 Qualification. Switches identified by PINs or type designation furnished under this specification and covered by
specification sheets shall be products which are qualified for listing on the applicable QPL at the time set for opening
of bids (see 4.3 and 6.3). The variations allowed from the specification sheet, included in 6.2.2, are as follows, and
shall be within the physical, functional, and environmental parameters of the specification sheet:
a. Indicator wheel color.
b. Indicator wheel marking.
c. Letters.
d. Spacers between switch stations.
e. Terminations.
f. Actuator color.
g. EMI/RFI.
h. Stops.
i. Circuit configurations (within the number of positions shown).
3.3 Material. The material shall be as specified herein. However, when a definite material is not specified, a
material will be used which will enable the switches to meet the performance requirements of this specification.
Acceptance or approval of any constituent material shall not be construed as a guaranty of the acceptance of the
finished product.
3.3.1 Insulation. Materials for insulation shall be used which shall enable the switch to meet the performance
requirements of this specification. Plastic materials shall be fungus inert and shall meet flammability requirements of
94V-0 in accordance with UL94. Thermoplastic materials shall also meet the following requirements:
Minimum heat deflection temperature of 375°F.
a.
b.
Maximum water absorption of 0.30 percent.
c.
Maximum dimensional stability (high temperature) of 0.12 percent.
3.3.1.1 Printed circuit board. Printed circuit boards shall be designed to enable the switch to meet the
performance requirements of this specification. When a conformal coating is specified it shall meet the requirements
of this performance document. Additional information and guidance on printed circuit boards and conformal coating
is provided in 6.7.
3.3.2 Metals. All metal parts, other than current-carrying parts, shall be of corrosion-resistant material or suitably
protected to resist corrosion.
3.3.2.1 Ferrous materials. Ferrous material shall not be used for current-carrying parts.
3.3.2.2 Dissimilar metals. When dissimilar metals are used in intimate contact with each other, protection against
electrolysis and corrosion shall be provided. The use of dissimilar metals in contact, which tend toward active
electrolytic corrosion (particularly brass, copper, or steel used in contact with aluminum or aluminum alloy), is not
acceptable. However, metal plating or metal spraying of dissimilar base metals to provide similar or suitable abutting
surfaces is permitted. The use of dissimilar metals separated by a suitable insulating material is also permitted. For
additional information and guidance on dissimilar metals see 6.8.
3.3.2.3 Pure tin. The use of pure tin, as an underplate or final finish, is prohibited both internally and externally.
Tin content of switch components and solder shall not exceed 97 percent, by mass. Tin shall be alloyed with a
minimum of 3 percent lead, by mass (see 6.15).
3.3.3 Protective coatings and finishes. That portion of the switch assembly which is visible from the front of the
panel shall have a black matte or lusterless finish in accordance with FED-STD-595, No. 37038.
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