Why Conformal Coat

Printed circuit boards are extremely susceptible to a wide range of contaminants that can cause a significant amount of damage in a relatively short period of time. These contaminants include moisture, dust and harmful chemicals. In addition, electronic circuits are also susceptible to extreme temperatures and environments. Conformal coatings provide a protective coating that can significantly reduce or eliminate contamination, whether the application is used in a relatively peaceful setting or in a harsh industrial environment.

Uses for Conformal Coating

Electronics are an important part of everyday life. These devices need to be protected from weather and harsh environments to ensure that they continue to operate effectively.

The conformal coating process is used in conjunction with the manufacturing of LEDs, MEMs and printed circuit boards in a wide variety of industries. Its main use is to prevent the contamination of insulating surfaces by ionic substances such as the oils from human hands and moisture from the environment.

These contaminants interrupt the unfettered flow of electrons through the circuit that ultimately results in degraded accuracy. While a conformal coating will, to a large degree, prevent this “ionic” degradation, it also substantially reduces the effects of mechanical stress due to vibration, and also thermally insulates the circuit.

Application Methods

Liquid conformal coatings can be applied in a variety of ways, depending on the needs of the end-user. Here are the most common application methods:

• Brushing – Extensively used in repair and low-volume applications, this method is relatively rare as it varies widely in quality depending on the skill of the applicator.
• Spraying – This method is an excellent choice for medium-volume applications, but only if the substrate is clean and the suitably adhesive.
• Dipping – This is the application of choice for almost all high-volume applications, however, proper preparation is essential as the coating will penetrate all areas of the application that are not properly masked.
• Robotic – In some instances,a robot may be used to selectively coat circuit boards using several of the processes listed above. In particular, robotic spraying can vary flow rates and viscosity and can use varying vacuum pressure to enhance the dipping process.

Curing and Drying

The application of the conformal coating is not the end of the process. To maintain the right thickness, the coated application must be dried in the appropriate environment and within the correct parameters. Depending on the variation of the coating, sometimes the cure can be over 30 days at room temperature.

Conformal coatings come in water-based and standard solvent formulations. Both are typically and economically air-dried, but both formulations also lend themselves to accelerated drying through the use of heat or UV curing.

Why Use Conformal Coating?

In many harsh environments, conformal coating is necessary for printed circuit boards and other electronics to maintain any degree of dependability and longevity. In addition, more benign environments will still degrade the accuracy and efficiency of unprotected circuit boards.

For these reasons, conformal coatings are a necessity for a wide variety of electronic circuits where uninterrupted service on critical equipment is necessary. In fact, the wide variety of conformal coatings available means that end-users can eliminate much of the uncertainty and costs associated with unexpected electronic failures and reduce their overall infrastructure and operating costs.