PCB circuit board is coatingConformal coatingAfter that, it can effectively prevent the damage of moisture to the circuit board, the circuit board is eroded by moisture for a long time, which will greatly reduce the insulation resistance between conductors, accelerate high-speed decomposition, reduce the Q value, and corrode the conductor. With the popularization of conformal coating in various fields of circuit boards, conformal coating is becoming more and more popular with everyone, but then it has also brought some technical problems to everyone
The curing time parameters of conformal coating mainly include surface drying time, initial curing time and completion time, and the curing form of conformal coating can be divided into room temperature curing, heating curing and UV curing, and the curing time of conformal coating is also very different between different curing methods.
1. Curing at room temperature.
Whether it is silicone conformal coating, polyurethane conformal coating or acrylic conformal coating, the curing surface drying time at room temperature is generally 10 15min, that is, a protective film is formed on the surface, and the internal conformal coating is not cured, so the circuit board can still not move at this timeThe initial curing time is generally 3 4h, at this time, the conformal coating of the circuit board reaches the initial curing, and the customer can transfer the circuit board to the designated drying area for complete curing;The complete curing time is generally 24h, and it can be put into normal use after complete curing.
2. Heating and curing.
The so-called heating curing is the process of accelerating the curing of the conformal coating by raising the surrounding environment after the circuit board is sprayed with conformal coatingUnder normal circumstances, when the temperature is about 60 80, it can be completely cured in 15min, and then cooled to room temperature after about 15min before use. The conformal coating made of silicone material does not meet the curing conditions at room temperature, and the curing time of the conformal coating used in the purchased silicone conformal coating will be compared.
3. UV curing.
UV curing is mainly reflected in UV conformal coating, and the curing time is mainly related to the power of UV lamps, and the curing time is about 10s. Of course, some companies will also carry out triple curing on the circuit board after UV curing - moisture curing, the specific curing time is related to the environment, due to the surface oxygen resistance problem of UV adhesive coating, it is necessary to increase the light requirements to achieve the purpose of forced curing.