PCB Board Conformal Coating
Three anti-conformal coating also known as PCB conformal coating, circuit board protection coating, anti-moisture coating, three-anti coating, anti-water coating, insulating coating, anti-corrosion coating, anti-salt coating, anti-dust coating, etc. PCB boards used three anti-conformal coating will have couples of good properties including waterproof, moisture-proof, dustproof, resistance to thermal shock, anti-aging, radiation resistance, salt spray resistance, ozone resistance, corrosion resistance, vibration resistance, good flexibility, strong adhesion strong, etc.
Moisture is the most common and most damaging factor for PCBs. Too much moisture can drastically reduce the insulation resistance between conductors, accelerate high-speed decomposition, reduce Q value, and corrode the conductors. If not use three anti-conformal coating, patina on the metal part of PCB boards are very common caused by chemical reaction among copper, water vapor and oxygen.
Hundreds of contaminants found casually on a printed circuit board have the same destructive power. They lead to the same result as moisture erosion like electron decay, corrosion of conductors or even irreversible short circuits. The pollutants most commonly found in electrical systems may be the chemicals left during the process. Examples of these contaminants are fluxes, solvent release agents, metal particles and marking inks. There are also major pollution sources that are inadvertently caused by human hands, such as body oils, fingerprints, cosmetics and food residues. Also many pollutants exist in the operating environment like salt spray, sand, fuel, acids, and other corrosive vapors and molds.
The three anti- conformal coating are used on the PCB board or components, when influence by unfriendly operating environment, it can reduce or eliminate the performance of electronic operating degradation. If the coating can maintain its effect for a satisfactory period of time, for example, longer than the product’s service life, it can be regarded as have reached its coating purpose.
Even the coating is very thin, it is also able to withstand mechanical vibration, thermal shock, and high temperature operation to some extent. However, the idea that the film can be used to impart mechanical strength or sufficient insulation to the individual parts on the PCB board is wrong.