There are four main methods for applying protective coating on PCB boards:
1. Brush coating method: This is the simplest conformal coating process, using high-quality natural fiber brushes to produce excellent coating effects on smooth surfaces.
2. Spraying method: Spraying method is the most commonly used coating method in the industry, and it is divided into two types: automatic machine spraying and manual spraying. Machine spraying can realize automatic feeding, save labor and material costs, improve production efficiency, ensure product consistency, and improve product quality.
3. Dip coating method: Dip coating ensures complete coating without causing material waste due to overspraying. The circuit board should be immersed for 1 minute until the bubbles disappear, and then taken out slowly. A uniform film layer will be formed on the surface of the circuit board.
4. Selective coating method: cover the areas not to be painted.
Before brushing or spraying the conformal protective paint, ensure that the diluted conformal protective paint is fully stirred and left for 2 hours before brushing or spraying. If machinery is required, the viscosity of the coating should be measured (using a viscosity agent or flow cup) and diluent can be used to adjust the viscosity. Do not immerse connectors unless carefully covered. Circuit boards should be immersed for 1 minute until bubbles disappear, then slowly removed. A uniform film layer will be formed on the surface of the circuit board. Most of the coating residue should be allowed to flow away from the circuit board and back into the dipping machine.