Basic principle and technical parameters of electrostatic spraying

The workpiece enters the spray gun position of the powder room through the conveying chain to prepare for spraying operation. The electrostatic generator releases high-voltage static electricity (negative electrode) to the space in the direction of the workpiece through the electrode needle at the nozzle of the spray gun. The high-voltage static electricity ionizes the mixture of powder and compressed air ejected from the nozzle of the spray gun and the air around the electrode (with negative charge). The workpiece is connected to the ground (grounding electrode) by means of transportation through the hanger, so that an electric field is formed between the spray gun and the workpiece and the powder reaches the workpiece surface under the double push of the electric field force and the compressed air pressure, and a uniform coating is formed on the workpiece surface by the electrostatic attraction.

Basic materials of powder electrostatic spraying

Indoor epoxy polyester powder coating is used. Its main components are epoxy resin, polyester resin, curing agent, pigment, filler, various auxiliaries (such as leveling agent, moisture-proof agent, corner modifier, etc.). After the powder is heated and solidified, the required coating is formed on the surface of the workpiece. The auxiliary material is compressed air, which is clean, dry, oil-free and anhydrous [water content is less than 1.3g/m3, oil content is less than 1.0 × 10-5% (mass fraction)

Construction technology of powder electrostatic spraying

● electrostatic high voltage 60-90kv. Too high voltage is easy to cause powder rebound and edge pockmarks; too low voltage powder loading rate is low.

● electrostatic current 10-20 μ a. Too high current is easy to produce discharge breakdown powder coating; too low current powder loading rate is low

● flow rate and pressure are 0.30-0.55mpa. The higher the flow rate and pressure is, the faster the deposition speed of the powder will be, which is conducive to quickly obtaining the coating of predetermined thickness, but the higher the flow rate and pressure is, the higher the powder dosage and the wear speed of the spray gun will be.

● atomization pressure 0.30-0.45mpa. A proper increase of atomization pressure can keep the thickness of powder coating uniform, but too high will make the powder feeding parts wear quickly. Reducing the atomization pressure properly can improve the covering ability of powder, but too low is easy to block the powder feeding parts.

● gun cleaning pressure 0.5MPa. Too high cleaning pressure will accelerate gun head wear, and too low is easy to cause gun head blockage.

● fluidization pressure of powder supply barrel is 0.04-0.10mpa. Too high fluidization pressure of powder supply barrel will reduce powder density and reduce production efficiency. Too low fluidization pressure may lead to insufficient powder supply or powder agglomeration.

● the distance from the nozzle to the workpiece is 150-300 mm. If the distance between the nozzle and the workpiece is too close, it is easy to produce discharge breakdown powder coating. If the distance is too far, it will increase powder consumption and reduce production efficiency.

● conveying chain speed is 4.5-5.5m/min. Too fast speed of conveying chain will cause insufficient thickness of powder coating, and too slow speed will reduce production efficiency.

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Adress：Hebei Industrial Zone,Jinxing Village,Tongqiao Town,Zhongkai High-Tech Zone,Huizhou City.