Why do PCB circuit boards need to use conformal coatings?

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Why do PCB circuit boards need to use conformal coatings? [Copy link]

Conformal coating is also called PCB electronic circuit board protection oil, coating oil, moisture-proof paint, three-proof coating, waterproof glue, insulating paint, anti-corrosion paint, anti-salt spray paint, dust-proof paint, protective paint, coating paint, three-proof glue, etc. PCB circuit boards that have used conformal coating have the "three-proof" properties of waterproof, moisture-proof and dust-proof, and are resistant to cold and hot shock, aging, radiation, salt spray, ozone corrosion, vibration, good flexibility, and strong adhesion.

Moisture is the most common and destructive factor for PCB circuit boards. Excessive moisture will greatly reduce the insulation resistance between conductors, accelerate high-speed decomposition, reduce Q value, and corrode conductors. We often see patina on the metal parts of PCB circuit boards, which is caused by the chemical reaction between the metal copper, water vapor and oxygen, which is not coated with three-proof paint.

The hundreds of contaminants found on printed circuit boards are just as destructive. They can cause the same results as moisture damage - electronic failure, corrosion of conductors and even irreparable short circuits. The most common contaminants found in electrical systems may be chemicals left over from the manufacturing process. Examples of these contaminants are flux, solvent release agents, metal particles and marking inks. There are also major groups of contaminants caused by human carelessness, such as body oils, fingerprints, makeup and food residues. There are also many contaminants in the operating environment, such as salt spray, sand, fuel, acid and other corrosive vapors and mold.

The application of conformal coatings to printed circuit boards and components can reduce or eliminate degradation of electronic operating performance when they may be affected by adverse operating conditions. If such coatings can maintain their effect for a satisfactory period of time, such as longer than the product's service life, they can be considered to have achieved their purpose.

Even if the coating is very thin, it can withstand mechanical vibration and oscillation, thermal shock, and operation at high temperatures to a certain extent. Of course, the idea that thin films can be used to give individual parts inserted into printed circuit boards mechanical strength or sufficient insulation is a mistake. Components must be mechanically inserted and must have their own suitable caulking agent, so that there is a double insurance against accidents.

shakencity

Conformal paint is also called PCB electronic circuit board protection oil, coating oil, moisture-proof paint, three-proof coating, waterproof glue, insulating paint, anti-corrosion paint, anti-salt spray paint, dust-proof paint, protective paint, coating paint, three-proof glue, etc. PCB circuit boards that have been coated with conformal paint have the properties of waterproof, moisture-proof, and dust-proof, as well as resistance to cold and heat shock, aging, radiation, salt spray, ozone corrosion, vibration, good flexibility, and strong adhesion. I didn't think about the many functions of conformal paint.