How to Select PCB Coating for PCBs' Optimal Performance

Up to now, electronics products involved in industries of Automotive, Military, Aerospace and Shipping or have to work in high-temperature and high-humidity environment possibly suffer from PCB (Printed Circuit Board) failure due to chemical environment, vibration, high temperature and high humidity, alternation between coldness and heat and salt fog, together with home appliances including air conditioner and washing machine etc. Moreover, PCB board and PCB components perhaps suffer from defects such as erosion, softening, deformation and moulding. Therefore, conformal coating should be sprayed onto the surface of circuit board so that electronic products will be more capable of withstanding environmental erosion and prolong their life time. Wide-ranging electronic products lead to massive classifications of PCB coating increasingly called for by industries. As a result, it has been a top concern for engineers to select a type of conformal coating with stable protective functions. This article aims at classifications and properties of PCB coating and provides pragmatic guidelines based on which optimal conformal coating can be picked up.

Classifications and Properties of PCB Coating

• Definition and Functions

The essential aim of applying PCB coating is to stop erosion from taking place on circuit boards or PCB components. As a type of special coating sprayed on circuit board surface, PCB coating is mainly responsible for prohibiting moulding, humidity and salt fog from occurring with other functions such as vibration resistance, insulation and circuit board design size reduction.

Applied on the surface of printed circuit board and PCB components together with other devices, PCB coating isolates circuits from bad environment so that assembled PCBs won't suffer from influence given by bad environment to finally protect circuits from environmental erosion that perhaps lead to circuit failure or electric leakage and to prolong life time of electronic products. In practical situation, PCB boards always suffer from erosion caused by bad environment and operating conditions, such as chemical surroundings, vibration, high dust, salt mist, humidity and high temperature etc. which will lead circuits to numerous defects such as break open failure, erosion failure, electronmigration failure, insulation failure and component failure, to name a few. 

PCB coating spray is capable of effectively isolating PCB boards and PCB components from their operating environment with security ratio improved and life time ensured. Furthermore, PCB coating is insulating in itself, which can stop electric leakage from taking place. Accordingly, PCB coating makes electronics products to feature higher power and smaller PCB spacing, compatible with the increasing requirement on component miniaturization.