Do You Know the Factors that Lead to the Loss of the PCB circuit board?

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

The triple paint is a specially formulated coating used to protect the PCB and its related equipment from the erosion of bad conditions. The three anti lacquer has good high and low-temperature resistance. It solidified into a transparent protective film. It can protect the circuit from damage such as chemical substances, vibration, moisture, salt fog, humidity, and high temperature. Under these conditions, PCB may be corroded, mold growth, and short-circuit. It has superior insulation, moisture-proof, leakage prevention, dustproof, anti-corrosion, anti-aging, anti-mold, anti-loose parts, and insulation corona resistance.

When three protective coatings are applied to printed circuit boards and components, the deterioration of electronic operation performance can be reduced or eliminated if the adverse factors of the operation environment are likely to be affected. If the lacquer can maintain its effect for a satisfactory period of time, such as the duration of the use of the product, it can be seen as the purpose of its coating.

Acrylic acid triple-proof varnish can provide comprehensive protection. Some acrylic products meet military standards. They are fast drying without drying. They can be removed by matching organic solvents. Therefore, three kinds of printed circuit boards are the most widely used and effective products in the market.

Whether the paint is toxic or not depends on the type of the three anti-paint thinners and solvents. If the three anti-lacquers are diluent with toluene or xylene as the diluent, the chemicals will be harmful to the human body, if the use of lipids and alcohols is less harmful. Xylene has moderate toxicity and stimulates the eye and upper respiratory tract. At high concentrations, it has an anesthetic effect on the central system.

Although there are many environmental protection paints on the market now, we still need to make protective measures in practice and wear gas masks when using them.

There are three kinds of lacquer used：

（1）brush coating - common use, can produce an excellent coating effect on a smooth surface.

（2）spraying - spray tank products can be easily applied to maintenance and small-scale production and use, and spray guns are suitable for the production of large-scale touch, but the two spraying methods require higher accuracy and may cause shadows.

（3）automatic dip coating - impregnating can ensure full film covering, and will not cause waste of material caused by excessive spraying.

Matters needing attention：

（1）if you want to get a thicker coating, you'd better get it by coating two layers of thin coating -- and the requirement must be completely dried on the first level before coating the second layers.

（2）when coating on PCB, the general connectors, software sockets, switches, radiators, heat dissipation areas, and panel areas are not allowed to have coating materials. It is recommended to use tear-resistant solder resist.

（3）the thickness of the film layer: the thickness of the film depends on the application method. The amount of diluent is large, the viscosity of the glue is low and the thickness of the coating is thin; on the contrary, the viscosity of the adhesive is high and the thickness of the coating is thick.

If repaired devices have been coated, remove the components directly by soldering the electric iron directly, and then install the new components. Then wash the area with a brush or solvent, then dry and repaint.