Military Standards for Safeguarding Printed Circuit Assemblies

For certain  service providers interested in working with aerospace companies or the U.S. Department of Defense (DOD), it is necessary to achieve certain military standards, also referred to as MIL-STD or MIL-SPEC. So what exactly is a MIL-SPEC? Essentially, these are specifications to define and standardize the technical requirements for materials that the DOD may purchase. The standards were established starting back in the 1960s to ensure reliability, maintainability, and to prequalify suppliers, thus lessening urgent supply chain demands.

In HZO’s business of protecting electronics from environmental contamination, the MIL-SPEC we keep a close eye on is MIL-I-46058C, which is the specification that lists the technical criteria for conformal coatings along with the requisite quality assurance tests and their testing protocol. The HZO material is based on para-xylylene, a polymer serving as an insulator and protective barrier to safeguard printed circuit assemblies.

Although MIL-I-46058C was deemed inactive for new designs, this requires more explanation. Isn’t that always the case? MIL-I-46058C does not detail a workmanship standard, nor is it a definition of quality. Rather, the spec ensures that the tested material is suitable for use as a conformal coating for electronic assemblies. Even though deemed inactive, MIL-I-46058C remains the defining standard for companies who supply conformal coatings for two important reasons: it is the only published standard that includes a qualified product list used by the DOD and the standard also requires certification by an independent third party.

Like all things, MIL-SPEC is one part of the equation. When choosing a protective barrier, it all starts by defining requirements including the environments to which the electronic assembly will be subjected. That’s the best way to keep electronics safe from damage.

* Image Courtesy of Empfasis, a publication of the National Electronics COE. For more information about types and qualities of conformal coatings visit:

https://www.empf.org/empfasis/2009/may09/conformal.html