Conformal coatings

Circuit board varnish, often also called conformal coating, is a good moisture protection for boards and components. There are a number of different types of circuit board lacquers, ranging from polyurethanes, acrylics, epoxies, silicones and even UV curing materials. Most of them are transparent or slightly colored, but there are also e.g. all black types. Many of them harden by some form of solvent leaving and then a polymerization takes place. However, some silicone-based types are completely solvent-free. Application of circuit board varnishes is often done by spraying the board or component, the advantage of spraying the varnish on the board in a robot cell is that you can easily and with great precision selectively varnish, on the surface you want to have varnished. Less often, the entire card is dipped. Lacquering circuit boards provides relatively good protection against moisture and contamination, but does not provide good heat dissipation, privacy protection or puncture protection.