What is Conformal Coating?

What Is Conformal Coating?

Conformal coating is the process where a thin, protective layer is applied to a PCB or other electronic components. This helps protect against dust, moisture, and other contaminants that could corrode essential parts over time, leading to device malfunction and failure. Carefully coating these elements extends their useful life and reduces the impact of vibration and shock.

What Materials Are Used for Conformal Coating PCBs?

Conformal coatings feature a one-part system with a resin base occasionally diluted with a solvent. These semi-permeable materials don’t fully seal the electronics, allowing for future repairs and adjustments. Most coatings are categorized by their base, which includes:

Acrylic Resin

Acrylic resin coatings are economical, easy to apply, and deliver quality protection from the elements. However, this option isn’t very effective at safeguarding against solvents and solvent vapors, including jet fuel fumes seen in aerospace applications.

Silicone Resin

Coating with a silicone resin base provides enhanced protection in various temperature ranges. It’s also highly chemically resistant and prevents moisture and salt spray from damaging components. Silicone resin’s enhanced flexibility makes it ideal for high-humidity environments. However, it can be difficult to remove, requiring specialized solvents and agitation from a brush.

Urethane Resin

Urethane coatings are known for being extremely moisture- and chemically resistant, making them ideal for aerospace applications. However, like silicone resin, this material is difficult to remove and requires a long soak time and agitation from a brush.

How to Apply Conformal Coating

The method used to apply the coating is essential. Failing to use the technique could lead to improper protection levels and leave components exposed to the elements, increasing the likelihood of malfunctions and equipment breakdown. Here are some common ways coatings can be applied:

Brush Coating

Brush coating involves applying a thin layer of material onto the surface of an electronic component using a brush or similar instrument. This method is ideal for small components with complex shapes and tight spaces because it allows the user to apply the coating with precision and accuracy. The brush coating method also provides excellent protection against corrosion and electrostatic discharge. However, it’s a tedious task that takes a lot of time and requires a careful hand to provide a proper coat.

Dip Coating

Dip coating is another popular coating application method. This requires the coater to fully submerge the component into a vat that contains the necessary material. Excess material is then removed by spinning or air drying. The dip-coating technique is typically used when significant amounts of PCBs need to be applied quickly and evenly.

Spray Coating

Spray coating is a common method for coating large surfaces and is done by spraying a thin layer of material on the component’s surface. The coating is then allowed to dry and cure. However, this application is only recommended for coverage on flat surfaces because it’s difficult to control what elements are coated.

See the Advantages of Our Conformal Coating Equipment

Want to see our conformal coating equipment in action? Check out our case studies and see the benefits of working with the Invention House team.

Our Case Studies

Enhance Conformal Coating for PCB With Invention House

Common methods for applying conformal coating require manual labor, and their effectiveness relies on the experience and knowledge of the user. This creates circumstances where coating jobs are inconsistent and impacts the efficiency of the devices powered by the PCBs. But what if there was a technique that produces a consistent coat across inventory? Invention House’s Raphael 4040 is an innovative automated conformal coating machine that reduces costs and increases efficiency by combining 3D automation and a robotic brush to coat boards.

The Raphael 4040 is ideal for businesses looking to replace their manual coating operations or are looking to add additional capacity, and offers the following benefits:

Increased quality: Our automated conformal coating machine increases quality because it has fewer passes, touches, and eliminates overspray.
Enhanced productivity: Traditional coating methods sometimes require extra board touches to ensure all elements are covered. Raphael 4040 minimizes board touches and reduces coating time by as much as four minutes.
Reduced costs: Masking and overspray waste lead to increased costs for businesses. The Raphael 4040 reduces spending by minimizing these issues.
Improved operator conditions: The Raphael 4040 enhances operator conditions by eliminating the need for masking and preventing interactions with cans and chemicals

Our Automated Conformal Coating Process

Unlike traditional coating processes that require precision and accuracy to properly protect components, the Raphael 4040 enables operators to complete the process using a joystick attachment and Raphael Suite, our proprietary software program. Your staff then uses the following steps to coat PCBs:

Step One: Import Board Image and Create a Layout

Operators begin programming the path by importing a Gerber file or board image, then set the PCB’s X, Y, and Z dimensions.

Step Two: Create the Coating Path

The operator uses the joystick, keyboard, and click-and-drag actions to create a series of coating segments. The initial path is created in a dry-run mode, which allows the user to implement tweaks until the optimal path is determined.

Step Three: Wet Run

After completing the dry-run path, the operator selects a single board, activates the pumps, and practices a wet run. Paying attention to coating flow and brush movement is essential to ensuring accuracy. This stage is where adjustments to brush height, flow rate, and speed are made.

Step Four: Production Run

Production conformal coating can begin after successfully completing a wet run. We recommend carefully inspecting early samples to make small path tweaks during this step.

Streamline Conformal Coating With Invention House

Enhancing productivity with innovative equipment is a top priority for the Invention House team. Along with the Raphael 4040, we also offer single-phase, 3-phase, and 400 Hz motor drives that power equipment in harsh environments. Contact our team today to learn more about our commitment to innovation.

Conformal Coating 101