Techspray FAQ: How do you apply conformal coating to a printed circuit board (also known as a PCB)?
Prepare the PCB
Ensure the PCB is clean, dry, and free from any contaminants. Clean it using an appropriate PCB cleaning solution or isopropyl alcohol to remove any dirt, flux residues, or other impurities that could interfere with the coatings adhesion.
Select the Conformal Coating
There are various types of conformal coatings available, such as acrylic (AR), silicone (SR), and urethane (UR). Choose a coating that suits your specific application and environmental conditions.
Masking Uncoated Areas: If certain components or areas on the PCB should remain uncoated (e.g., connectors, switches, or heat sinks), use a masking material (e.g., Kapton tape or liquid latex) to protect those areas during the coating process.
Choose the Application Method:
Conformal coatings can be applied using different methods, including spraying, dipping, brushing, or dispensing. The method you choose depends on the type of coating and your equipment's capabilities.
Spraying: Suitable for large-scale production. It requires a specialized spray booth and spray gun to evenly apply the coating.
Dipping: Involves immersing the entire PCB into a reservoir of conformal coating. This method provides uniform coverage but may trap air bubbles.
Brushing: This is a Manual application using a brush it’s suitable for small-scale production or touch-ups.
Machine dispensing: This applies the coating using a controlled dispensing system, which is useful for selective coating on specific areas of the PCB.
Curing and Drying
Allow the applied conformal coating to cure and dry as per the manufacturer's instructions. This typically involves leaving the coated PCB in a controlled environment, such as an oven, for the recommended duration of time.
Post-Coating Inspection
After the coating has cured, inspect the PCB to ensure proper coverage and to check for any defects, such as bubbles, pinholes, or insufficient coating.
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PROTECT ELECTRONICS FROM EXTREME ENVIRONMENTS
Techspray offers SR, AR and UR conformal coating formulas for a wide variety engineering requirements including thermal, moisture & static resistance. All coatings are IPC-CC-830B and UL94 V-0 qualified.
Techspray offers a variety of conformal coating formulas for differing field or engineering requirements and is IPC CC 830B and UL94-0 Qualified or rated. Specifications generally depend on the type of protection needed: e.g., thermal, moisture, or static resistance.
Coatings contain Opti/Scan (except LED Coating) to allow quality control inspection of coverage and evenness of the coating on a PCB. A coated board can be passed under a standard, low-cost UV (short-wave black) light to fluoresce the coated areas. The brighter the glow, the thicker the coating.
Application methods:
Dip – High volume method to fully coat boards. Thickness of the final coating is controlled by viscosity and withdrawal speed from the pot.
Conformal Coating Spray – Computer controlled selective spray systems eliminate the need for masking. Higher viscosity is generally needed (70-200 cps) to create precise edge definition and prevent splattering.
Manual Application – Aerosol and brushing are generally used for small production runs, rework and repair. The aerosol needs to be compatible with the original coating if it’s rework.
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https://www.techspray.com
Techspray is a leading manufacturer of chemical products and soldering tools for the electronics industry. Techspray formulates, blends, and packages a wide variety of chemicals and assorted support products for the electronics industry, aerospace, heavy industry, and plant and equipment maintenance including degreasers, contact cleaners, flux removers, dusters, conformal coating, solder mask, water-based cleaners, desoldering wick, soldering tips, and the popular Plato shear cutters. More information can be found at techspray.com.