Conformal coating is a protective nonconductive dielectric layer that is applied onto the printed circuit board assembly to protect the electronic assembly from damage due to contamination, salt spray, moisture, fungus, dust and corrosion caused by harsh or extreme environments.
Conformal coatings are usually used in products that are made for use in outdoor environments where heat and moisture are prevalent. Coating also prevents damage from rough handling, installation, and reduction of mechanical and thermal stresses. It also prolongs the life of the product during its operation. At the same time, it helps to increase the dielectric strength between conductors enabling the design of the PCB to be more compact and small. It also acts to protect circuitry and components from abrasion and solvents.
After the coating process is complete the coating is clearly visible as a clear and shiny material. Some coatings are hard, while others have a slightly rubbery texture. Most coatings include a marker that appears greenish white when viewed under UV light. This marker enables easy inspection of the coating thoroughness checking during production.
In the past, coatings were only applied to military and life/medical products as the cost and the process was significantly higher per unit. In recent years the development of materials and new processes has enabled a larger variety of items to be coated, including a wide array of consumer electronics products. As prices continue to drop, conformal coating will become increasingly common for circuitry and electronic components, especially as these items continue to shrink in size and dimension.
Conformal coating started as a simple process performed on electronic substrates in need of extra protection from external elements, with little attention paid to quality factors beyond adequate component coverage. The increased capability of semiconductor assemblies to perform complex tasks in automotive applications, traffic control, signage, outdoor surveillance, and mission-critical elements has increased the demand for conformal coating. Because device failure could have dire consequences, the quality of coating material application is critical. New equipment and processes are in place to accommodate the conformal coating requirements of these emerging technologies. A smooth transition to automated precision conformal coating can be achieved through an analysis of the product being coated and the desired result, the coating material used, the process selected, and of the economic costs over a period of time.
To learn more about conformal coating solutions from Diamond MT, and to learn how you can get started, please contact us today!