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PCB Assemblies Protection: Conformal Coating
The author:  Pageviews:5083  Release time:2020-01-07 05:49:55


What's Conformal Coating?

A Conformal Coating is a special formulation of chemical coating, used to protect the circuit board and related equipment from environmental erosion. After curing, it becomes a protective film, which is with superior insulation, moisture-proof, leakage-proof, shockproof, dust-proof, anti-corrosion, anti-aging, corona resistance and other properties.


With the protective nature of conformal coating, this process is becoming increasingly common in electronic PCB assemblies to enhance and extend the product’s service life and ensure the safety and reliability. In another words, it will reduce the potential cost and damaging effects of early field failures; including portable devices comprising fine pitch, densely populated assemblies, such as mobile phones, through to washing machines.



How do conformal coatings work?


A conformal coating plays an role as a protective barrier that shields sensitive electronic components against harsh environmental conditions such as moisture, chemicals and debris. They are not designed to be a total sealant. Conformal coatings are a breathable protective layer that will protect against the particular environment requirement but will also allow any moisture trapped in the circuit board to escape.



How to apply Conformal Coating?


To be effective, a conformal coating should completely cover the PCB assembly and provide good coverage of sharp edges (components and component leads) and other contours (solder joints for example). It may even be essential to coat the edges of the board, as these will not even have any solder resist present.


The effectiveness of the coating is, to some degree, influenced by the efficiency of the application method, which also governs the type of coating used. There are essentially four main ways of applying a conformal coating:


1. Dipping – limited to materials that do not cure quickly by moisture, oxidation or light

2. Selective robotic coating – All coating types can be used if the correct dispense head is selected

3. Spraying – hand spray using a spray booth or aerosol can. All coatings can be applied in this way

4. Brushing – requires extremely proficient and skilled operators in order to be suitable for production purposes


Finally you will have to consider the curing method determined by the coating selected, air dry, oven dry or UV light cure. The liquid coating should thoroughly wet all surfaces and cure without leaving surface defects. Epoxies are especially sensitive to surface defects. Epoxies can also shrink while setting and may lose adhesion as a result In addition; excessive shrinking during cure can place severe mechanical stresses upon circuit components.

As a turnkey Printed Circuit Board Fabrication and Assembly Manufacturer, Seasons Electronics can meet your requirements of conformal coating requirements.