The basic process of electrostatic powder spraying on aluminum profiles

There are usually three forms of surface treatment for aluminum profiles: electrophoresis, electrostatic powder spraying, and fluorocarbon spraying. Electrophoresis is the process of applying a voltage to an electrophoretic coating at the anode and cathode, causing charged coating ions to move to the cathode and react with the alkaline surface of the cathode to form insoluble substances, which then deposit on the surface of the workpiece. The basic process of electrostatic powder spraying on aluminum profiles.

(1) Surface pretreatment:

Chemical pretreatment method can be used for sheet metal stamping parts. Namely: degreasing → rust removal → cleaning → phosphating (or purification), etc. Most rusted or thick surface workpieces are removed by mechanical methods such as sandblasting and shot blasting, but after mechanical rust removal, the surface of the workpiece should be ensured to be clean and free of scale.

(2) Spray coating:

The workpiece enters the spray gun position in the powder spraying room through the conveyor chain to prepare for spraying operations. The electrostatic generator releases high-voltage static electricity (negative electrode) towards the space in the direction of the workpiece through the electrode needle at the nozzle of the spray gun. This high-voltage static electricity ionizes the mixture of powder and compressed air sprayed from the nozzle and the air around the electrode (with negative charge). The workpiece is grounded through a conveying link (grounding electrode) through a hanging device, which forms an electric field between the spray gun and the workpiece. The powder reaches the surface of the workpiece under the dual push of electric field force and compressed air pressure, and relies on electrostatic attraction to form a uniform coating on the surface of the workpiece.

(3) Baking and curing:

The sprayed workpiece is transported by a conveyor chain to a drying room at 180-200 ℃ for heating, and kept warm for a corresponding time (15-20 minutes) to melt, level, and solidify, thus obtaining the desired surface effect of the workpiece. Different powders have different baking temperatures and times. This should be noted in the curing process.