1. In the actual SMT chip processing, if you only want to improve the insulation level and corrosion resistance of the PCB surface, you can usually use the process of spraying coating directly on the PCBA surface of the no-clean soldering process. If it is necessary to have effective "three-proof" protection, then the coating must be carried out strictly accordance with the requirements of the electronic processing plant for the conformal coating process.
2. In the actual processing, even if no-clean SMT soldering flux is used for SMT processing, there will still be residues such as rosin left on the board, and these residues will react with the conformal coating paint and cause pinholes. It will even crystallize and swell due to moisture. The final result is that the coating of the conformal coating paint will fall off and will not work. Therefore, the PCBA must be thoroughly cleaned before the operation of the coating process to achieve good results.
3. In the process of spraying method, the paint film may cause pinholes after curing. In order to better achieve a good moisture barrier level, it must be sprayed twice. This is also one of the effective measures to ensure the thickness of the coating on the circuit.