Electrostatic Powder Enamel (2) - Electrostatic Powder Enamel Coating Mechanism

Release time:

2026-03-27 09:07

Source:

China Enamel Industry Association

(Continued from previous article)

3. Electrostatic Powder Enamel Coating Mechanism

3.1 Electrostatic enamel powder charging occurs in two ways: Corona discharge and triboelectric static electricity.

3.1.1 Corona Discharge Coating is Widely Used. This method uses a needle-shaped electrode to generate a voltage of 60-100 kV, ionizing the air around the spray gun to produce negatively charged oxygen ions. These oxygen ions encounter the enamel powder at a distance of 1-2 cm from the electrode, charging it. The powder then adheres to the workpiece surface through the electric field. Corona discharge coating can be divided into several steps, including powder charging, powder transport, and powder deposition. Figure 1 is a simplified diagram of this coating method.

3.1.1.1 Powder Charging. In this area, the electrostatic spray gun generates a voltage of 60-100 kV, ionizing the surrounding air to form positively charged nitrogen ions and negatively charged oxygen ions. The nitrogen ions immediately release their charge, while the negatively charged oxygen ions encounter the enamel particles, charging them negatively at a distance of 1-2 cm from the spray gun. 

3.1.1.2 Powder Conveying. Negatively charged enamel powder adheres to the workpiece surface along the magnetic field lines. The distance between the workpiece and the spray gun is typically 20-30 cm. Due to the aerodynamic influence of the charged powder during movement, the spray gun air pressure needs to be monitored during operation.

 

3.1.1.3 Powder Deposition. When the charged powder encounters a grounded workpiece, it is deposited and adsorbed onto the workpiece surface due to the electric field. The set powder deposition thickness is achieved by adjusting the spray gun voltage, air pressure, and the distance between the spray gun and the workpiece.

 

3.1.2 Triboelectric Static Electricity Method: Enamel powder generates static electricity through friction during its delivery to the spray gun via a pipeline. Because the charge on the powder after friction is weak and it's impossible to determine whether its charge matches that of the spray gun, this method is not as valuable as corona discharge.

Previous Page

None

Electrostatic Powder Enamel

Next Page

Previous Page

None

Next Page

Electrostatic Powder Enamel