A Quick Look on Conformal Coating

Conformal coating is a polymeric film that protects electronic components on a printed circuit board from environmental factors. These factors include but are not limited to dirt, dust, heat, humidity, temperature and chemicals. There are different types of conformal coatings based on the resin used. These are acrylic resin (AR), silicone resin (SR) and urethane resin (UR). Each one has its own advantages/disadvantages and should be chosen based on the needs of application.

Acrylic conformal coating is an affordable solution that is easy to apply and remove, which allows for easy future reworks. However, acrylic coating does not provide the best protection when compared to other options. It is not ideal for harsh environments or high temperature conditions. It also has low chemical resistance. Acrylic coating can be considered as basic entry-level protection.

Silicone conformal coating is well suited to extreme temperatures unlike acrylic coating. It also has excellent humidity and corrosion resistance and good chemical resistance. While having these advantages, silicone coating is a more expensive solution and is also very difficult to remove, which does not make it the ideal choice for PCBs that may require future reworks. Silicone coating is commonly used in high-humidity environments.

Urethane conformal coating has excellent moisture and chemical resistance. It is also very resistant to mechanical wear. However, like silicone, it is very difficult to remove. A good example for urethane conformal coating application is aerospace environments where exposure to fuel vapors is a common concern.

As explained above, conformal coating provides significant advantages and may be that extra element you need for better reliability and durability for your applications. Choosing the right coating method is crucial though since each has its own drawbacks and an inappropriate selection may end up causing more trouble than benefit. As ForeCR, we provide the option to apply conformal coating in our products if demanded to meet the needs of our customers.