The thermosetting powder coating is applied by a high-voltage, low-current electrostatic Powder coating spray process. When spraying, an automatic Powder coating line consisting of a manual powder coating gun or multiple spray guns can be used. Friction guns that work on the principle of triboelectric charging are not effective for all types of powder coatings. When using such guns, attention should be paid to the type of powder coating.
The powder coating is sent from the powder feeder to the powder feeding tube under clean and dry compressed air, and then sent to the high-pressure electrostatic spray gun by the airflow. The corona discharge at the outlet of the powder gun causes the powder coating particles to be electrostatically negatively charged. The charged powder coating is adsorbed on the grounded workpiece by means of the air flow. After the electrostatically charged powder is adsorbed on the workpiece, the adsorption force is large and has a certain adhesive force. The general airflow or slight vibration cannot cause the powder to fall off.
In order to ensure high quality coating, construction should be strictly carried out:
1. The storage of powder coatings should be stored in a cool, dry condition and sealed and used strictly in batch order.
2. Before the workpiece is sprayed, the oil stains and pollutants on all surfaces should be completely removed, and the workpiece should be properly treated.
3. The compressed air should be oil-free, water-free and dry. Check the working condition of the oil-water separator frequently.
4. The structure design of the workpiece holder should be reasonable and maintain a good connection with the ground transmission part. Fixtures should be cleaned regularly to maintain good grounding.
5, the correct choice of powder coating required for the final coating
6, the curing heating oven temperature control system performance should be stable, should be able to ensure the conditions required to cure the coating.
7. The powder feeder, recycling system and spray cabinet should be free from contamination, and no other powders should be mixed, otherwise the appearance of the final coating will be affected.
8. Check the performance of the treatment, the performance of the curing oven, and check the physical properties of the powder used.
9. The recycled powder must be sieved and mixed with new powder according to the specified ratio.
10. Silicon dust or paint dust should be avoided in the vicinity of the powder coating spraying site to avoid affecting the appearance quality.