DEPARTMENT OF THE AIR FORCE SMC REGULATION 800-32
Headquarters Space and Missile Systems Center (AFMC)
Los Angeles Air Force Base, California 90009-2960
Conformal Coating of Electrical
This regulation establishes policies and procedures and assigns responsibilities for SMC program office acquisitions that contain certain types of electrical components in SMC launch and space vehicles programs and their associated ground equipment.
Both metallic and insulating surfaces in electronic boxes, such as printed wiring assemblies, where contamination could cause electrical malfunction shall be conformally coated unless otherwise insulated or hermetically sealed.
Conformal coatings such as those specified in MIL-I-46058, "Insulating Compounds, Electrical (For Coating Printed Circuit Assemblies)" are used in electronics applications to provide protection to electrically active surfaces. The conformal coating may be dipped, sprayed, brushed or vacuum deposited, as described in MIL-STD-275E, "Printed Wiring for Electronic Equipment", onto the surface it is designed to protect. For applications in space, conformal coatings provide protection against corrosive contamination, moisture, and shorting by conductive debris; in ground applications, they also provide protection against corrosive gases and mechanical damage. Significant program impacts have been observed on several classified programs (1991-92) and on Titan IV (1993) due to shorting by metallic contamination.
3. Responsibilities and Procedures
a. Selection of conformal coatings and their thicknesses shall meet the requirements of MIL-I-46058, or equivalent.
b. For SMC launch and space vehicle programs each program office shall ensure that conformal coatings are used on all suitable electrical components (components unsuitable for conformal coatings are addressed in paragraph 3.c). Specifically excluded from this conformal coating requirement shall be unjacketed, flexible shielded cable and ground straps.
c. Unsuitable components: certain components will suffer significant performance degradation if conformally coated. In these situations, non-use of conformal coatings on electrical components and hardware must be supported by a thorough analysis and be specifically approved by the System Program Director on a case by case basis
d. Instructions for applying and executing this regulation are provided by SMC Regulation 540-15 (Systems Engineering Policy). Any program director who does not apply and execute this regulation, as required by SMCR 540-15, shall immediately request a waiver from the Commander.
Edward P. Barry, Jr.
Lieutenant General, USAF