Conformal coating standards, explained

Ask three suppliers whether their coating "meets the standard" and you will get three answers, because there is no single standard. Material qualification, workmanship acceptance and process guidance are three separate documents, and a supplier can be entirely truthful about one while silent on the others. This page separates them.

The map

IPC-CC-830B — qualifying the material

IPC-CC-830B is the qualification and performance specification for electrical insulating compound applied over printed board assemblies. It is what a coating chemistry is tested against: appearance, dielectric withstand, insulation resistance, thermal shock, moisture and insulation resistance under humidity, flexibility, fungus resistance and flammability, among others.

When a manufacturer states that a coating is qualified to IPC-CC-830B, the claim is about the material in laboratory conditions. It says nothing about whether it was applied correctly to your board. That is the next document's job.

The ELPEGUARD systems EMS supplies come from Lackwerke Peters with their own qualification and test documentation, and our engineers will provide the relevant data for whichever grade is proposed for your assembly.

IPC-A-610 — judging the coated assembly

IPC-A-610, Acceptability of Electronic Assemblies, is the workmanship standard. Its conformal coating section is what an inspector uses to decide whether a coated board passes: coverage over the areas that should be coated, clearance on the areas that should not be, thickness within the agreed band, and the absence of defects such as bridging, dewetting, blistering, delamination, cracking, orange peel, entrapped foreign material and coating that has crept onto a keep-out area.

The three acceptance classes

• Class 1 — General Electronic Products. Assemblies where the requirement is function. Cosmetic imperfection is not a rejection.
• Class 2 — Dedicated Service Electronic Products. Continued performance and extended life are required; uninterrupted service is desired but not critical. Most industrial, automotive, commercial and telecom assemblies belong here.
• Class 3 — High Performance / Harsh Environment Electronic Products. Continued performance on demand is essential, downtime cannot be tolerated, and the end-use environment may be uncommonly harsh. Life-support, aerospace, defence and critical control systems.

The class belongs on the drawing. Where it is absent, a supplier will apply their default, and "we assumed Class 2" is a poor conversation to have after a lot has shipped.

MIL-I-46058C — cancelled, but still quoted

For decades MIL-I-46058C was the conformal coating qualification, and its Qualified Products List was how buyers identified approved materials. It was cancelled and the QPL discontinued, with IPC-CC-830 named as the superseding specification. IPC-CC-830B carried the substance of it forward into the commercial standards world.

It nevertheless persists — on legacy drawings, in customer specifications copied forward across product generations, and on datasheets where a coating is still described as historically QPL-listed. Two practical rules:

• For new specifications, cite IPC-CC-830B.
• If an incoming drawing calls out MIL-I-46058C, treat it as a request for an equivalently qualified material, confirm in writing which document the lot will actually be judged against, and record it on the process sheet.

IPC-HDBK-830 — the process handbook

IPC-HDBK-830 is guidance rather than a pass/fail specification, covering selection, surface preparation, application methods, masking, cure, inspection and rework. It is the document that connects the other two: it explains how a material qualified under IPC-CC-830B ends up producing an assembly that passes IPC-A-610. For a team standing up a coating process for the first time, it is the most immediately useful of the set.

Standards you may also be asked for

• IEC 61086 series — international requirements for coatings used on assembled printed boards; frequently invoked on export work.
• UL 746E / UL recognition — where the end product's safety certification requires a recognised insulating system.
• IPC-J-STD-001 — requirements for soldered assemblies, whose cleanliness provisions materially affect coating adhesion, and therefore sit upstream of every coating decision.
• Customer and OEM specifications — automotive and aerospace primes routinely impose their own document on top of the IPC set. Read it before quoting; it usually tightens something.

What to put on your drawing

A conformal coating callout that avoids most downstream argument states all six of these:

1. Coating type and, where fixed, the specific grade — for example an ELPEGUARD polyurethane system.
2. The material qualification reference: IPC-CC-830B.
3. The acceptance standard and class: IPC-A-610, Class 2 or Class 3.
4. The dry film thickness band, and where on the assembly it is measured.
5. Keep-out areas, marked on the drawing itself rather than described in a note.
6. The inspection method — UV inspection coverage, and how thickness is verified.

How EMS applies this

Every lot we coat is inspected under UV rather than sampled, measured against the thickness band agreed at process sign-off, and judged against the IPC-A-610 class stated for the product. The services page sets out the full inspection and release regime, and our engineers can review an incoming customer specification with you before you commit to it.