What are conformal coatings?
Conformal coatings are thin-layer polymers that are applied to the surface of printed circuit boards (PCBs), with typical thickness between 25μm to 150μ, to protect and electrically insulate the circuits and board components from environmental stresses. The coatings ensure PCB reliability in environments where moisture, condensation, dust, dirt, salts, chemicals, abrasion, thermal and mechanical shock, and other factors can all affect circuit performance. The products were originally developed for use in military applications. They enable design of smaller electrical assemblies, while increasing mechanical support for components, and improving the fatigue life of solder joints.
Industries such as aerospace and defense, consumer and automotive electronics, telecom, and appliance manufacturing integrate printed circuit boards into their products. Many of these applications require conformally coated PCBs to protect them from potentially harsh environments, such as satellites that are exposed to extreme space (atmospheric) conditions and sensitive PCB circuitry and sensors in automotive electronics subjected to continuous use.
Five Key Reasons to Use Conformal Coatings on PCBs
Each year the electronics industry calls for smaller printed circuit boards to function in more aggressive and rigorous environments. Conformal coatings are applied to the surface of PCBs to protect and insulate circuits from harsh environments, or to increase the dielectric voltage-withstand capability between conductors. Here are five compelling reasons to use them in your application:
1. Provide Complete Protection: Conformal coatings are engineered to protect circuit boards from humidity, dust, fungus, extreme temperatures, and other contaminants. These coatings can be resistant to many types of solvents and chemical attack and can also be heat resistant. Normally, a circuit board exposed to these types of environments would degrade, but a conformal coating can slow down the effects or even prevent them. If left uncoated, leakage or corrosion can take place, damaging delicate parts.
2. Improve Dielectric Properties: When a conformal coating is applied to a PCB, it protects against corrosion and arching, while increasing mechanical support for components and improving fatigue life of solder joints. It also helps condense the circuit footprint, allowing for tighter spacing between components. In addition, it significantly slows tin whisker growth, reducing the risk of whiskers creating a short between adjacent conductors.
3. Can be Easily Applied: The coatings can be sprayed, dipped, or brushed. With a single coat they provide reliable protection to rigid board and flexible film laminates as well as to metal, glass, or plastic substrates. They’re easily dispensed and for thicker coating requirements, some materials can be applied in multiple passes.
4. Save Time and Cost: Conformal coatings allow for lighter weight, smaller assemblies due to the elimination of housings and enclosures. For manufacturers, fewer repairs to printed circuit boards mean less time and labor, and MORE savings.
5. Protect Sensitive Information: Some conformal coatings are available in opaque colors to help cover markings, labeling, and other identification on circuit boards.