Electrostatic powder coating machines are widely used in various industrial coating fields, especially for surface treatment of metals, plastics, and aluminum profiles. They use the principle of electrostatic adsorption to evenly apply powder coating to the surface of workpieces, which then forms a hard coating through the curing process.

1. Preparation of Powder Coating
Electrostatic powder coating uses dry powder coatings, mainly composed of resin, curing agents, and pigments. Before use, powder coatings need to be preprocessed using specific equipment and procedures:
– Powder selection: The type of powder coating is chosen based on customer requirements and the needs of the workpiece. Common types include polyester, epoxy, and polyurethane, suitable for different applications.
– Powder transportation: Powder coatings are transported to the spray gun through specialized conveyance systems, such as pneumatic conveying systems.

2. Spraying Process: Principle of Electrostatic Spraying
The core principle of an electrostatic powder coating machine is electrostatic adsorption. The spray gun charges the powder coating via a high-voltage power source, while the workpiece is grounded or carries an opposite charge. The main steps of the spraying process are as follows:

Charging
– Power on: The spray gun is connected to a high-voltage power supply, generating high voltage (usually between 30-100 kV), which charges the powder inside the gun negatively.
– Powder charging: As the powder coating is sprayed, it is charged via the corona discharge principle. The discharge creates a negative charge on the powder particles, which are then attracted to the workpiece’s surface.

Powder spraying
– Spray gun operation: The gun uses compressed air to spray the powder onto the workpiece. The charged powder is attracted to the grounded workpiece, ensuring even coverage.
– Spray uniformity: During spraying, adjustments are made to the spray angle, powder flow, and spray distance to ensure uniform coating on the workpiece.

Electrostatic adsorption
– Electrostatic adsorption: Because the workpiece carries an opposite charge to the powder, the powder is strongly attracted to the surface, ensuring it adheres evenly without sagging or dripping, providing uniformity and quality.
– Spray gun distance: To ensure even coating, the distance between the gun and the workpiece must be precisely controlled, usually 20-30 cm from the surface, to avoid too much or too little powder.

Electrostatic powder coating machines use electrostatic adsorption to spray powder evenly onto the workpiece surface and solidify it through a curing process to create a hard and durable coating. Powder recovery systems improve material utilization, reduce waste, and ensure environmental and economic benefits. The entire process is efficient and environmentally friendly, suitable for various industries such as automotive, home appliances, electronics, and metal processing.