Powder spraying uses the phenomenon of corona discharge to make the powder coating adsorb on the workpiece. The process of powder spraying is: the powder spray gun is connected to the negative electrode, the workpiece is grounded (positive electrode), the powder coating is fed into the spray gun by the powder supply system by means of compressed air gas, and a high voltage generated by a high-voltage electrostatic generator is added to the front of the spray gun. A dense charge is generated near it. When the powder is sprayed from the gun nozzle, it forms a circuit to form charged paint particles, which are attracted to the workpiece with the opposite polarity due to the electrostatic force. The more the accumulation is, when it reaches a certain thickness, due to the electrostatic repulsion, the adsorption will not continue, so that the entire workpiece can obtain a powder coating of a certain thickness, and then the powder will be melted, leveled, and solidified by heat, that is, on the surface of the workpiece. Forms a hard coating.