Standard Operation and Daily Maintenance of Electrostatic Spray Gun

Label:Electrostatic Spray Gun, Daily Maintenance, Powder Coating, Sheet Metal

Jul 7, 20216560

Standard Operation and Daily Maintenance of Electrostatic Spray Gun

The working principle of electrostatic powder coating:

The electrostatic powder spray gun is connected to a high-voltage electrostatic generator. When the spray gun electrode is connected with high-voltage static electricity, a high-voltage electrostatic field is generated between the anode and the workpiece, and a corona discharge is formed at the mouth of the gun.

When the powder coating is delivered by the purified air from the powder feeder to the spray gun, the atomized powder becomes negatively charged particles. The powder flies to the surface of the workpiece along the direction of the electric field force under the action of the air flow and the electric field. But only adsorbed on the surface, the coating reaches a certain thickness after melted by heating, curing the leveling coating by the action of a uniform coulombic electrostatic attraction.

Due to its superiority, powder coating technology is widely used in industries including sheet metal, automobiles, home appliances, engineering machinery, and construction. As a key part of the powder coating electrostatic spray gun that affects the powder coating rate, we need to pay great attention to it, and we must also carry out standardized operations and daily maintenance.

Preparation Before Spraying

1. Before powder spraying, we must carry out strict pre-treatment (degreasing, rust removal, phosphating) of the workpiece, and accurately hang it to ensure that the equipment is well grounded;

2. Start and check the air source of the system;

3. Turn on the exhaust fan of the powder spraying room, and turn on the spraying equipment to be in working condition. The powder rises with the fluidized air flow, and the surface of the powder layer only boils slowly. After the powder continues to fluidize for 5-10 minutes, we will start spraying again. Make sure that the spray gun is not triggered, then turn on the power to the controller;

4. The spraying personnel should wear suitable work clothes, and filter breathing equipment should be used if possible.

Use of Powder Spray Gun

1. Point the powder spray gun at the powder spraying chamber, pull the trigger to start test spraying the workpiece;

2. Adjust the electrostatic high voltage, electrostatic current, powder volume pressure and atomization pressure:

(1) Electrostatic high voltage 65-100kV: Too high voltage is easy to cause powder rebound and edge pitting; too low voltage is easy to cause low powdering rate;

(2) Electrostatic current 15-30uA: Too high current is prone to discharge and breakdown the powder coating; too low current will also cause low powder coating rate;

(3) Powder volume air pressure 2.0~4.5kgf/㎡: The higher the powder volume pressure, the faster the powder deposition speed, which is beneficial to quickly obtain the required coating thickness. However, if it is too high, it will increase the amount of powder and the wear rate of powder spray gun consumables.

Routine Maintenance of Spray Gun

1. Point the spray gun at the spray booth and purge the spray gun. We should blow clean the powder deposits in the spray gun. In this way, powder deposition and powder flushing can be avoided to the greatest extent when spraying again;

2. Cut off the air source and power supply of the system;

3. Disassemble the powder feed hose connector and purge the powder passage of the spray gun;

4. Disconnect the powder feed hose;

5. The consumable parts of electrostatic equipment should be checked and replaced regularly, including: powder core, spray gun electrode needle, protection block, air pipe, powder tube, powder tube in the gun;

6. Purge the spray gun, use a cleaning cloth to wipe the surface of the spray gun; use a powder duct brush to clean the powder passage in the gun;

7. Some possible failures and solutions of the spray gun during the spraying process: refer to the manual of each brand or call the brand supplier for on-site inspection.