15/09/2026
Is Your Conformal Coating Actually Working? Here's How to Verify It.
Conformal coating protects a PCB assembly from moisture, salt spray, dust, fungus, and corrosion — the slow damage that adds up fast in outdoor or harsh operating environments. It also shields against rough handling, reduces mechanical and thermal stress, and extends the product's operational life.
But here's the catch: applying the coating is only half the job. A coating that looks fine to the naked eye can still have pinholes, thin spots, or gaps around components — and you won't know until the assembly fails in the field.
That's where UV inspection comes in. Most conformal coatings contain a UV-reactive additive, so under the right light, coverage either fluoresces clearly — or it doesn't.
What to check when inspecting conformal coating:
🔘 Full coverage — confirm the coating reaches every intended area, including tight spots around components and connectors
🔘 No unintended coverage — verify keep-out zones (connectors, test points, mounting holes) are actually clear
🔘 Uniform thickness — look for thin spots or pooling that can signal inconsistent application
🔘 No visible defects — check for bubbles, cracks, or contamination trapped under the coating
Catching these issues at inspection is far cheaper than catching them after deployment.
👇 Full video walkthrough in the comments — see exactly what to look for and how to catch defects before they become field failures.
