Conformal Coating on Electronics

An extra resistance shield to electronics boards

Industrial electronics and electronics boards can enjoy a wide array of benefits from conformal coating, for example:

Better stability to environmental variables

Increased preservation of the board over time

Enhanced stability and general performances

What exactly is conformal coating?

Conformal coating is nearly always associated with the product it gives the name to. But in reality, conformal coating is first and foremost a production process that is carried out when the cooperation of the following elements:

Specific equipment and specific machinery
Properly trained personnel
Polymers with precise features

These polymers are commonly called Conformal Coating because, as a matter of fact, they represent the substances used to coat the printed circuits in order to make them conformal. What do they need to conform to? Well, they conform to needs of various kinds, sometimes purely technical, sometimes functional and sometimes even regulatory.

Primary Scope

The primary scope of conformal coating is the protection of the printed circuits and of the components that are mounted on them. The coating protects from a wide range of elements, among which the most common are:

Environmental infiltration
Dust
Impurities
Chemical agents
Humidity
Extreme Temperatures

The protection assured by the coating provides prevention of damages caused by corrosion, moulding, infiltrations and electric deficiency.

Parameters like viscosity, density/surface ratio, dosage and safe areas detection must be carefully measured.

Accuracy and experience are extremely important for the effectiveness of the entire conformal coating process.

Application Method

The most conventional methods of application are the following:

Dip Coating, which consists of immersing the parts that need to be coated into the substance that will act as protective coat.
Selective Roboting Coating, which consists of a series of processes completely automated and executed by proper industrial equipment.
Spray Coating, in which the coating is transformed into a mist that gets sprayed on top of selected areas.
Brush Coating, which makes use of proper brushes designed to distribute the polymers on surfaces of different size.

Each and every method has its own strengths and the choice of which one is best suited for a specific product is very case sensitive. In CTA Electronics, we can count on a proper production department entirely equipped for conformal coating, which allows us to execute the selective roboting coating as well as any other kind of application.

Substances and Materials

The primary reason why there are many different kinds of conformal coating resides in the fact that every polymer has its own defining feature. Simplifying, we can say there are mainly four product families:

Acrylic polymers, particularly resistant to environmental agents but not so performing in terms of chemical resistance;
Polyurethans, that combine an excellent chemical resistance to a remarkable protection from external agressions and variuos agents like humidity and extreme temperatures;
Silicon polymers, extremely hard to remove and re-work, they guarantee optimal endurance;
UV cure polymers, they activate after a photochemical reaction arising from UV light and they assure infallible resistance to abrasion and to chemical agents.

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