Conformal Coating Play in Printing Circuit Boards

Conformal coating is a protective layer that’s applied in a thin coat over a printed circuit board (PCB) and its exposed metal, solder joints and components. It’s essential to the functionality of a printing circuit boards and provides a number of protective functions such as moisture resistance, waterproofing and insulation.

In addition to protecting against corrosion, which is the most common failure of a PCB, conformal coating offers other benefits such as increasing usable surface area on the PCB. This is a key concern for senior electronics engineers who are constantly being challenged to fit more parts onto smaller boards.

Typically, conformal coatings are used on electronic products that are subject to harsh environments such as aerospace, defence and medical applications. This is due to the fact that these devices are more susceptible to environmental conditions such as high humidity, a wide range of airborne contaminants and varying temperatures.

To protect against the deterioration of a conformal coating, it’s necessary to have accurate and repeatable measurement processes that ensure a consistent coating thickness across the entire PCB. This allows the coating to perform optimally under these varying conditions. There are several different measurement methods used in the conformal coating industry. One of the most popular is the Eddy current probe method which uses a test probe that’s placed flat against the surface of the PCB. This method is both non-destructive and highly accurate but can be limited if there’s no metal backplane or a direct contact available underneath the probe head.

What Role Does Conformal Coating Play in Printing Circuit Boards?

Another measuring technique involves using a micrometer to compare measurements before and after the application of a conformal coating to determine its consistency and uniformity. This method is also non-destructive and can be used on both wet or dry samples. However, it can be difficult to get a uniform coat with this method since the conformal coating may be applied unevenly.

A third measuring technique involves the use of ultrasound. This is an entirely non-destructive and repeatable method that’s able to measure the thickness of a conformal coating at both wet and dry samples. This is a quick and easy way to get consistent results that can be used for comparison.

Finally, a fourth method involves the use of a UV light to illuminate the sample and thereby detect any imperfections that are present in the coating. This can be a very effective way to detect any discoloration or imperfections that aren’t visible to the naked eye.

While conformal coating can offer a wide variety of benefits, it’s crucial to select the correct material for your specific application. This will depend on a number of factors including the environment the electronics are going to be in, their sensitivity and how durable you require them to be. Conformal coatings that meet the requirements of IPC class 3 equipment are generally preferred by many electronic contract manufacturers.

When choosing a conformal coating for your printed circuit board, make sure that it complies with the EPA’s restrictions on ozone depleting chemicals and other environmental hazards. Additionally, it’s important to ensure that the curing process is thorough and that your conformal coating is cured evenly across the whole surface of the PCB.

Leave a Reply

Your email address will not be published. Required fields are marked *