Why does PCB need to use three proofing paint?

The three proofing paint is also called PCB electronic circuit board protective oil, coating oil, moisture-proof paint, three proofing paint, waterproof glue, insulating paint, anti-corrosion paint, salt spray paint, dust-proof paint, protective paint, coating paint, three proofing glue, etc. the PCB circuit board with three proofing paint has the "three proofing" properties of waterproof, moisture-proof and dust-proof, cold and heat shock resistance, aging resistance, radiation resistance, salt spray resistance, ozone corrosion resistance Vibration resistance, good flexibility and strong adhesion.

When the three proof paint coating machine is applied to the printed circuit board and components, when it may be affected by the adverse factors of the operating environment, it can reduce or eliminate the deterioration of electronic operating performance. If the coating can maintain its function for a satisfactory period of time, such as longer than the service life of the product, it can be regarded as having achieved its coating purpose.

Moisture is the most common and destructive factor to PCB. Excessive moisture will greatly reduce the insulation resistance between conductors, accelerate high-speed decomposition, reduce Q value and corrode conductors. We often see that the metal part of PCB circuit board has copper green, which is caused by the chemical reaction of copper, water vapor and oxygen.

Hundreds of pollutants found casually on printed circuit boards have the same destructive power. They can lead to the same results as moisture erosion - Electronic decay, corrosion of conductors, and even irreversible short circuits. The most common pollutants found in electrical systems may be chemicals left over from the process. These pollutants include, for example, flux, solvent release agent, metal particles and marking ink. There are also major pollution groups caused by careless handling, such as human grease, fingerprints, cosmetics and food residues. There are also many pollutants in the operating environment, such as salt spray, sand, fuel, acid, and other corrosive steam and mold.

Even if the coating layer is very thin, it can withstand mechanical vibration, swing, thermal shock and operation at high temperature to a certain extent. Of course, the idea that thin films can be used to provide mechanical strength or sufficient insulation to the various parts inserted into the printed circuit board is wrong. The parts and components must be firmly inserted by mechanical means and have their own suitable joint sealant, so as to have double insurance to prevent accidents.