How To Keep The PCB Away From Moisture
In the summer of Shenzhen, when you go out to eat, The whether is sunny. But it may be raining after dinner. Summer is not only hot, but it often rains. The heat is steamed and moist, and the water is full of space. At this time, the human body is most susceptible to "liver disease." Shushi disease is a common exogenous disease in summer. People may have fever, aversion to cold, sweating, dizziness, headache, vomiting, diarrhea, greasy tongue, and pulse symptoms. Outdoors, jogging, walking, hiking and other outdoor sports can be effectively damped. In addition, eating and dampness is also a good method. You can choose different formulas based on your physique. With a strong constitution, people can adopt the traditional "appropriate", "five flowers", the body can be weak and can take the spleen and sputum and stomach, eliminate hawthorn, malt, Divine Comedy, etc. It will be beneficial to our body.
The three-coat is a specially formulated coating that protects the board and its associated equipment from environmental damage. The three anti-paint has good resistance to high and low temperature; it cures into a transparent protective film to protect the circuit from damage in the case of chemicals (such as fuel, coolant, etc.), vibration, humidity, salt spray, humidity and high temperature. .Because under these conditions, the board may be corroded, mold growth and short circuit, etc., the three coatings have superior insulation, moisture, leakage, dust, corrosion, anti-aging, anti-mildew, anti-loose and insulated corona.
Moisture is the most common and destructive factor in PCB boards. Excessive moisture greatly reduces the insulation resistance between the conductors, accelerates high-speed decomposition, lowers the Q value, and corrodes the conductor. We often see that the metal part of the PCB board is patina. Because it is not coated with three layers of paint, metallic copper reacts with water vapor and oxygen to produce copper rust.
Then how to keep the PCB away from moisture?
Three layers of anti-paint are applied to printed circuit boards and components. If it may be affected by unfavorable operating conditions, electronic performance degradation can be reduced or eliminated. Draping paint can maintain this effect. The board is larger than the life of the product, which is also the purpose of the coating.
The acrylic three-layer coating is flexible and provides total protection. Because it is a one-component system, it has good adhesion, simple operation, low requirements on equipment and conditions, convenient structure, high transparency, high brightness, short operating cycle, etc., so it is easy to use and easy to remove. Some acrylic products meet military standards, they dry quickly, but they are not drying, and they can be removed with a matching organic solvent, so this type of circuit board three anti-paint is one of the most versatile and effective products on the market.
Whether the three anti-paints are toxic depends on the three anti-paint diluents and the type of solvent used. If three anti-paints use toluene and xylene as diluents, this chemical is harmful to humans. If lipids, alcohols, etc. are used, they are less harmful to humans. Xylene is moderately toxic and has a stimulating effect on the eyes and upper respiratory tract. At high concentrations, it has an anesthetic effect on the central nervous system.
There are four types of three anti-paint applications:
1.Brush - Produces an excellent coating on a smooth surface.
2.Spraying - Spray cans are easy to apply to maintenance and small-scale production, spray guns are suitable for mass production, but these two spray methods require high precision, may produce shadows (the lower part of the components is not covered with three anti-paint).
3, automatic dip coating - dip coating to ensure the completion of film formation, will not cause material waste caused by over-spraying.
4. Selective coating of film - Precise coating, no waste of material, suitable for large volume coatings, but high requirements for coating equipment. Most suitable for large-volume coatings. Reduce the cloak by programming the XY table. When the PCB is painted, there are many connectors that do not require painting. The tape is too slow and there is too much glue left in the tear. Consider the shape, size and position of the connector, make a combined cover, and position it with the mounting holes. Cover unpainted parts.