The role of three anti-glue |
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| Reading Volume： 【 2188 】 | Time： 【 2017-06-06 】 | |
| Under existing conditions, especially outdoors, such as chemical, vibration, high dust, salt spray, humidity and high temperature environments, electronic circuit boards are very likely to have corrosion, softening, deformation, mildew and other problems, resulting in circuit boards The circuit is malfunctioning. The smear material is applied to the surface of the circuit board to form a protective film with three-proof ability (three-proof refers to moisture-proof, anti-salt spray and anti-mildew). In the presence of chemical substances (such as fuel, coolant, etc.), vibration, humidity, salt spray, humidity and high temperature, the circuit board without coating material may be corroded, mold growth and short circuit, etc., causing the circuit to appear In case of failure, the use of coating materials can protect the circuit from damage, thereby improving the reliability of the circuit board, increasing its safety factor, and ensuring its service life. In addition, because the coated material can prevent leakage and arc breakdown between electronic components, it allows higher power and closer printed board spacing, thereby meeting the purpose of miniaturization of circuit boards and components. Moisture is the most common and destructive main factor for PCB circuit boards. Excessive moisture will greatly reduce the insulation resistance between conductors, accelerate high-speed decomposition, reduce the Q value, and corrode the conductors. We often see the patina on the metal part of the PCB circuit board, which is caused by the chemical reaction of copper, water vapor, and oxygen without coating the three-proof paint. Hundreds of pollutants can be found casually on printed circuit boards, and these pollutants have a certain destructive power. They can cause 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 manufacturing process. Examples of these contaminants include fluxes, solvent release agents, metal particles and marking inks. There are also major pollution groups that are caused by humans carelessly, such as body oils, fingerprints, cosmetics and food residues. There are also many pollutants in the operating environment, such as salt spray, sand, fuel, acid, and other corrosive vapors and bacteria. Coating materials on printed circuit boards and components can reduce or eliminate the degradation of electronic operating performance when it may be affected by adverse factors in the operating environment. If this coating paint can maintain its effect for a satisfactory period of time, such as longer than the product's service life, it can be deemed to have achieved its coating purpose. Even if the coating layer is very thin, it can withstand mechanical vibration and swing, thermal shock, and operation under high temperature to a certain extent. Of course, the idea that the film can be used to make the individual parts inserted in the printed circuit board have mechanical strength or sufficient insulation is wrong. The components must be mechanically inserted, and they must have their own suitable caulking agent, so that there is double insurance to prevent accidents. |
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