MIL-I-46058C Test

Military Protective Coating Test

MIL-I-46058C, Amendment 7: Insulation Compound, Military Specification for Electricity (For Coating Printed Circuit Board Assemblies)

This military standard specifies requirements for suitability and suitability for conformal coatings and determines those suitable for application to printed circuit board assemblies by immersion, brushing, spraying or vacuum deposition.

The status of this standard is “not effective for the new design” but it can still be tested and placed in the Qualified Products List (QPL) if successful. This list is protected because all military manufacturers must choose and use skins from this list.

This standard outlines the qualification and quality compliance test for a compatible coating that is intended to be listed in the Defense Logistics Agency (DLA) Qualified Products List (QPL). The protective coating manufacturer must provide the appropriate 19M form that the DLA will receive and provide a reference number. Once this is received, the manufacturer will select an approved laboratory that has been DLA-inspected. The coated samples are sent to the laboratory and the tests are made according to the information sent by the manufacturers:

•  First Qualification: A coating that is newly formulated and tested for the first time and must meet the tests listed in Table I of MIL-I-46058C (page 5).
•  Protection of Qualification: In order to maintain the qualification, the coating manufacturer must submit reports for Groups A and B, including a summary of the results showing the number of passes and / or fails, and the number and failure of the Group C failure. This will be reported to the screening event (DLA) every 24 months.

Note: If a discrepancy is found and no corrective action is taken by the DLA, or if it is not considered acceptable, the management agency may take action to remove the product from the QPL.

•     Group A Inspection will be performed in each lot according to Table II of MIL-I-46058C (page 6).
• Group B Inspection will be carried out on a coating that conforms to Group A and to be tested in the order shown in Table III in MIL-I-46058C (page 7), and the test will be done from the production lot every 12 months.
•  Group C Inspection will be carried out on a coating that meets Group A and B, and MIL-I-46058C (page 7) will be tested according to Table IV, and the test will be done every 24 months from the production lot.

Test substrates consist of glass samples, tin panels, bare laminate and y-patterns (copper or tin lead coated). The qualification table details the samples used for each test and section 4.7 (page 8), how to prepare the test samples before coating and testing. It should be remembered that some test results must be obtained before coating.

There are five types of conformal coatings: AR (Acrylic), ER (Epoxy), UR (Polyurethane), SR (Silicone) and XY (Paraxylene).

It should be noted that, as noted earlier, although the specification was considered passive for the new design, the management agency might be eligible to eventually revise this standard if sufficient interest was created to revise this specification (its last revision was September 14, 1993).