PCBs (printed circuit boards) are subjected to many harsh environmental conditions. This includes extreme temperatures, strong chemicals, corrosive salts, dust and moisture. Therefore, encapsulating them with a protective conformal coating makes sense. Conformal coatings keep harmful elements from touching the delicate components and degrading the performance of the boards. However, for optimum PCB longevity, functionality and reliability it is imperative that the boards are perfectly clean and dry before conformal coating.
PCB contamination comes from many sources including transport, handling, storage and manufacturing. The most common examples of PCB contamination are varied. They include fingerprint oils and salts, flux residue. Also, tape or other adhesive residue, solder balls, and even some inks or chip bonder.