To protect a printed circuit board (PCB) from the elements, including moisture, dust and extreme temperatures, conformal coatings are often applied. But there are several types to choose from, so how can you be certain you're making the right call? Below we'll cover the five main types of coating, as well as advantages and disadvantages of each.
Conformal coating is a polymeric film that covers, and conforms to,circuit board components and other electronics. Its primary purpose is to protect electronics from environmental elements and corrosion. The coating acts as both a protective shield and insulative material for a PCB.
Humiseal.com outlines the following benefits of coating your PCB:
While many varieties of coating exist – including a few specialty types – there are five main categories based on the substances' chemical makeup. The categories are:urethane resin (UR),epoxy resin (ER),acrylic resin (AR),silicone resin (SR) and parylene (XY).Below are descriptions,pros and cons of each. When selecting a coating, the most critical consideration should be the application and required functionality of your electronics within that application.
Urethane resins can be either single- or double-part substances.
Acrylic resins are preformed acrylic polymers that have been dissolved in a solvent (source: ACI Technologies). They are typically one-part substances.
