MIL-PRF-22710 Switches, Code Indicating Wheel \(Printed Circuit\), Thumbwheel And Push-Button, General Specification ForThis specification covers the general requirements for illuminated and non-illuminated, thumbwheel \(see 6.4.1\), and push-button, printed circuit rotary switches having unsealed and sealed modules and the associated hardware. These switches are designed for low power alternating current \(ac\) and direct current \(dc\) switching applications for use in electronic and communication equipment. Procurement of switches and mounting hardware will require additional data, giving detailed electrical and mechanical requirements, tolerances, and applicable additions and exceptions to the general requirements and tests specified herein \(see 6.2\).

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MIL-PRF-22710H

6.6 Insulation (see 3.3.1).

6.6.1 Thermoplastic. It is recommended that thermoplastic materials be tested in accordance with MIL-M-24519 to

the requirements specified in 3.3.1.

6.7 Printed circuit boards. It is recommended that printed circuit board design be accomplished in accordance with

MIL-PRF-31032

6.7.1 Conformal coating. It is recommended that conformal coating material be in accordance with MIL-I-46058

and be applied to meet the requirements specified in 3.3.1.1.

6.8 Dissimilar metals (see 3.3.2.2). Dissimilar metals and compatible couples are defined in MIL-STD-889.

6.9 Potting compounds (see 3.3.5). It is recommended that potting compounds that meet requirement 47 of

MIL-HDBK-454 be considered for use.

6.10 Terminal finishes and platings ( see 3.4.3.1, y, 3.4.5.2).

6.10.1 Gold plating. It is recommended that SAE-AMS2422, type III, class 1 be considered for meeting the gold

plating requirements of this specification.

6.10.2 Tin-lead plating. It is recommended that SAE-AMS-P-81728 be considered for meeting the tin-lead plating

requirements of this specification.

6.10.3 Nickel plating. It is recommended that SAE-AMS-QQ-N-290 be considered for meeting the nickel

requirements of this specification.

6.10.4 Silver plating. It is recommended that ASTM-B700 be considered for meeting the silver requirements of this

specification.

6.10.5 Hot soldering dip. It is recommended that solder dip (60-40 tin lead), in accordance with J-STD-006, be

considered for meeting the requirements of this specification.

6.11 Locking sealant. It is recommended that ASTM-D5363 be considered for meeting the locking sealant

requirements of this specification in 3.4.1.2.

6.12 Subject term (key word) listing.

Communication

Electronic

Illuminated

Legend

Low power

Luminance

6.13 PIN. This specification requires a PIN that describes technology and appropriate references to associated

documents (see 1.2.1 and 3.1).

6.14 Environmentally preferable material. Environmentally preferable materials should be used to the maximum

extent possible to meet the requirements of this specification. As of the dating of this document, the U.S.

Environmental Protection Agency (EPA) is focusing efforts on reducing 31 priority chemicals. The list of chemicals

and additional information is available on their website at https://www.epa.gov/osw/hazard/wastemin/priority.htm.

Included in the EPA list of 31 priority chemicals are cadmium, lead, and mercury. Use of these materials should be

minimized or eliminated unless needed to meet the requirements specified herein (see Section 3).

6.15 Tin whisker growth. The use of alloys with tin content greater than 97 percent, by mass, may exhibit tin

whisker growth problems after manufacture. Tin whiskers may occur anytime from a day to years after manufacture

and can develop under typical operating conditions, on products that use such materials. Conformal coatings applied

over top of a whisker-prone surface will not prevent the formation of tin whiskers. Alloys of 3 percent lead, by mass,

have shown to inhibit the growth of tin whiskers. For additional information on this matter, refer to ASTM-B545

(Standard Specification for Electrodeposited Coatings of Tin).