What is the Best Way to Protect PCBs?
Have you ever considered how circuit boards can sit around in contact with fluids for hours on end even at elevated temperatures? Think of automotive printed circuit boards (PCBs). They’re a good example of how such delicate electronic boards survive harsh environments.
Automotive electronic circuits started out as simple switches for headlights and windshields wipers; they have evolved significantly ever since. GPS navigation systems, anti-lock brake systems, climate controls, electronic throttle controls and EGR valves are just some features that have provided more safety, comfort and entertainment in automobiles.
Automotive manufacturers face the challenge of finding reliable, economical and high-performance circuit materials that minimize the effects of early field failures. Properly protected PCBs will guard the boards from fluids that may damage and/or compromise the safety and operation of the vehicle.
Conformal coatings, such as those manufactured by Dymax, are often applied to printed circuit boards to improve circuit reliability in harsh conditions. They are a protective layer of thin polymeric material that conforms to the contours of a printed circuit board to protect components. Light-curable conformal coatings are engineered to protect circuit boards from humidity, dust, fungus, extreme temperatures and other contaminants. If left uncoated, leakage or corrosion can take place; and such delicate parts can be damaged.
In an attempt to better serve its customers, Dymax recently conducted a study to examine how four of its leading conformal coatings (9482, 9481-E, 9-20557, and 984-LVUF) tested for chemical resistance against seven fluids commonly used in the automobile industry.
The conformal coatings were applied to printed circuit boards and cured using a Dymax 5000-EC Flood Lamp and the appropriate heat or moisture secondary cure based on chemistry. The printed circuit boards were then immersed in the test fluids for 72 hours, after which they were removed and wiped clean. The boards were left at room temperature for one week. The initial weights of the coated boards were recorded as well as the weights after the 72 hour soak and after one week.
The following table shows the results:
Want to perform your own experiment?
If you are exploring options for protecting your PCBs, our team of Applications Engineers will be happy to help you evaluate your requirements and choose the appropriate product to meet your needs. Contact us now.