Definition

Conformal coating is a thin protective film applied to assembled PCBs to shield components and circuitry from environmental hazards. Common coating materials include acrylic (easy rework), silicone (wide temperature range), polyurethane (chemical resistance), and epoxy (hard, durable). The coating conforms to board contours at 25-250 µm thickness, protecting against moisture, dust, chemicals, and temperature extremes while providing electrical insulation. Application methods include spraying, dipping, and selective coating. Specify conformal coating for automotive, aerospace, marine, and industrial environments. Design considerations: define keep-out areas for connectors and test points, and note that coated boards are harder to rework.