Discussion on the Attention Points of UV Moisture Three proof Paint Coating Process
2021-07-05 1664
In the production of electronic products, PCB circuit boards are very important components, and the surface of PCB circuit boards usually needs to be coated with a layer of three proof adhesive to protect them from external environmental damage. Compared to traditional solvent based three proof adhesives, UV three proof adhesives have replaced solvent based three proof adhesives in many fields due to their environmental protection, curing speed, protective performance, operational flexibility, and high solid content.
Clean and dry the board to remove moisture and moisture: Before applying glue, it is necessary to remove dust, moisture, and oil stains from the surface of the object to be coated, so that it can fully exert its protective effect. Thorough cleaning ensures that corrosive residues are completely removed and allows the adhesive to adhere well to the surface of the circuit board.
2. The adhesive can be coated by brushing: the brushing area should be larger than the area occupied by the device to ensure full coverage of the device and solder pads.
3. When brushing, the PCB board should be placed flat as much as possible, and there should be no dripping after brushing. The brushing should be smooth and there should be no exposed parts, and it is recommended to be between 0.1 and 0.3mm.
4. Before brushing or spraying, ensure that the diluted product is thoroughly stirred, and let it stand for 2 hours before brushing or spraying. Use a high-quality natural fiber brush to gently brush and dip at room temperature. If using machinery, the viscosity of the coating should be measured (using a viscosity agent or flow cup), and a diluent can be used to adjust the viscosity.
5. The circuit board components should be vertically immersed in the coating residue. The connector should not be immersed unless carefully covered. The circuit board should be immersed for 1 minute until the bubbles disappear, and then slowly removed. A uniform film layer will form on the surface of the circuit board. Most of the paint residue should be allowed to flow back from the circuit board to the impregnation machine. TFCF has different coating requirements. The immersion speed of circuit boards or components should not be too fast to avoid generating too many bubbles.
When using the adhesive again after the immersion coating is completed, if there is any peeling on the surface, remove the skin and continue to use.
7. After coating is completed, the PCB board is cured by UVLED curing machine irradiation. If some gaps are not fully cured, the PCB board can be placed for secondary moisture curing.
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