A conformal coating protects the circuit board during its lifetime of use
A conformal coating is a protective non conductive dielectric layer that is applied onto the printed circuit board assembly surface to protect the electronic assembly during its working life.
The coating protects from damage due to contamination, salt spray, moisture, fungus, dust and corrosion caused by harsh or extreme environments.
It is usually used on electronic products that are exposed to adverse environments where heat, chemicals and / or moisture are prevalent.
Conformal coating also can prevent damage from rough handling, installation, reduction of mechanical and thermal stress.
It can prolong the life of the product during its operation and at the same time, it can help to increase the dielectric strength between conductors enabling the design of the PCB to be more compact and small.
Finally, it also acts to protect circuitry and components from abrasion and solvents.
What does the conformal coating look like?
When coated, it 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 view under UV light. This marker enables easy inspection of the coating thoroughness checking during production.
Where are conformal coatings used?
In the past, coatings were only applied to military and safety critical products like medical devices as the cost and the process of doing this was high.
In recent years, the development in material and new processes has enabled consumer electronics products such as tablets, mobile phones, white goods and wearable technologies to be coated as well.
This will be becoming more common and will become a norm as circuitry and electronic components continue to shrink in size and dimension.
How are conformal coatings applied?
The coatings can be applied in many ways including dipping, brushing and spraying.
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.
How critical is the application process?
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.
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