Conformal coating is a protective chemical coating or polymer film that ‘conforms’ to the circuit board topology. The purpose of conformal coating is to protect PCBA’s from harsh environments that may contain moisture and or chemical contaminants. By being electrically insulating, it maintains longterm surface insulation resistance (SIR) levels and thus ensures the operational integrity of the assembly. It also provides a barrier to airborne contaminants thus preventing corrosion.
The protective nature of conformal coatings also means that they not only protect, but also serve to enhance product reliability and thereby reduce the potential cost and damaging effects of early field failures. Conformal coatings are a breathable protective layers that will protect against the particular environment requirement but will also allow any moisture trapped in the circuit board to escape.
The particular advantages of conformal coatings can be summarized as follows:
*Insulating properties allow a reduction in PCB conductor spacing of over 80%
*Can help eliminate the need for complex, sophisticated enclosures
*Completely protect the assembly against chemical and corrosive attack
*Eliminate potential performance degradation due to environmental hazards
*Minimize environmental stress on a PCB assembly
To be effective, conformal coating should completely cover the assembly and provide good coverage of sharp edges (components and component leads) and other contours (solder joints for example). It may even be essential to coat the edges of the board, as these will not even have any solder resist present.
The effectiveness of the coating is, to some degree, influenced by the efficiency of the application method, which also governs the type of coating used (some suppliers offer dedicated versions of the same coating product to suit different application methods). Let the BEI engineering team review your conformal coating requirements and provide a solution that meets your needs.