QPE Blog: Conformal coating: protecting PCB assemblies in demanding environments

Electronic assemblies do not always operate in clean, dry or temperature-controlled conditions. Moisture, dust and other contaminants can affect performance and contribute to deterioration over time.

Conformal coating provides an additional protective layer over the PCB and its components. At QPE, this capability supports assemblies that need environmental protection as part of their manufacturing requirements.

What is conformal coating?

Conformal coating is a thin protective film that follows the contours of a populated PCB.

Its purpose is to help protect vulnerable surfaces and electrical connections from environmental exposure. When appropriately selected and applied, it can help reduce the risk of corrosion and electrical problems associated with moisture and contamination.

It is particularly relevant to products used in industrial, transport, defence and other demanding applications, where operating conditions influence the protection an assembly needs.

Selecting protection for the application

The coating requirements should reflect the product’s intended operating environment.

Exposure to humidity, condensation or chemicals may influence the choice of coating, alongside operating temperatures and any inspection, maintenance or repair requirements.

Different coating materials offer different properties. The selection therefore needs to match the application and its specification rather than assuming that one coating will suit every product.

Conformal coating forms part of the overall protection strategy, alongside considerations such as enclosure design and the conditions in which the equipment will operate.

Why controlled application matters

Effective coating requires more than covering the board. Specified areas need suitable coverage, while other parts must remain free of coating.

Connectors, contact surfaces and designated test points, for example, may need masking or selective application so they can continue to function as intended.

Preparation, coverage, thickness and curing requirements also need attention. Controlling these factors helps achieve consistent protection without interfering with the assembly’s operation.

At QPE, coating requirements are considered as part of the build specification, helping ensure the process suits the product.

What this means for customers

For customers whose products face environmental exposure, conformal coating can help:

• Protect against moisture and contamination.

• Reduce the risk of corrosion.

• Support long-term assembly reliability.

• Meet specified environmental protection requirements.

  
  

The level of protection depends on the coating selected, its application and the conditions the product encounters.

By considering these requirements during manufacturing planning, customers can establish how coating will fit into the build, including any areas that need to remain accessible for connection, inspection or servicing.

Does your product need additional environmental protection? Contact QPE to discuss conformal coating for your PCB assemblies.