Understanding the Conformal Coating Process

Conformal Coating Process

The conformal coating process ensures a PCB can endure the conditions of their working environment, protecting it from moisture, vibration, and more.

Conformal coating is a protective chemical coating or polymer film that “conforms” to the topology of a circuit board, protecting the electrical circuits in harsh environments. Care must be taken during the preparation, application, and drying stages of the conformal coating process as flaws in the deposited film can compromise its function and negatively affect unit performance. That is why it is important to choose an experienced PCB assembly service, such as Telan, who specializes in this service.

What Does the Conformal Coating Process Do?

Conformal coating is a protective barrier that guards sensitive electronic components from harsh environmental conditions such as:

• Moisture

• Aggressive chemicals and vapors

• Salt sprays

• Mechanical vibration

• Fungus

• Large temperature variations

• And more

The coating is not a total sealant, but a breathable layer that protects the circuits against particular environments while also allowing any moisture trapped in the PCB to escape. Other benefits include:

• Enhanced product reliability, thus reducing the costs and damaging effects of early field failures

• Light weight

• Can eliminate the need for complex enclosures

• Insulating properties allow for a reduction in PCB conductor spacing of over 80%

There are four types of conformal coating: acrylic, epoxy, silicone, and urethane. Each has a specific range of performance properties that make them more beneficial for certain applications than others. Understanding their properties and how they interact with the components they cover helps mitigate potential defects and minimize performance failure. As one of our premium services, Telan’s technicians are experts at the conformal coating process and can help you choose the correct coating for your project.

How is Conformal Coating Applied?

To be truly effective, conformal coating must completely cover the assembly and provide good coverage of sharp edges (such as components and component leads) and contours (such as solder joints). There are four main methods for applying the conformal coating:

1. Dipping - This is for materials that do not cure quickly by moisture, light, or oxidation.

2. Spraying - Done with either a spray booth or aerosol can, this method is compatible with all coating types.

3. Brushing - This method requires a highly skilled hand and is not always feasible for large production runs.

4. Selective robotic coating - All coating types can be applied by these machines thanks to interchangable dispenser heads.

Trust Your PCB to the Experts at Telan

From turnkey assembly and box builds, to flexible circuits and multilayer boards, Telan has been producing high-quality electronics for over 35 years. We are fully compliant to IPC-610 standards, assuring our conformal coating process will meet all your needs and requirements. For more information about conformal coating, call us today at 215-997-7603.