Electrostatic spray gun, Powder coating gun, Liquid coating spray gun

In a coating production line, the electrostatic spray gun is the core equipment for surface treatment. It efficiently and rapidly sprays paint onto the surface of the workpiece using a low-pressure, high-atomization device and an electrostatic generator to create an electrostatic field, achieving a good surface finish. Therefore, it is both a paint atomizer and an electrostatic electrode generator.

What is electrostatic spraying & How it work?

The electrostatic spray gun uses the grounded workpiece as the positive electrode and the paint atomizing device as the negative electrode. The paint atomizing device is given a high negative voltage, creating an electrostatic interface between the two electrodes. This causes the atomized paint particles to become negatively charged, effectively attracting the paint to the workpiece surface, which is the opposite electrode. Why is the workpiece the positive electrode and the paint atomizing device the negative electrode? Because reversing these polarities makes spark discharge more difficult and unsafe.

For electrostatic coating to be effective, grounding of the workpiece is essential; therefore, the workpiece must be a good electrical conductor. Wood is generally considered a poor conductor of electricity, but when its moisture content is above 8%, electrostatic coating can be performed, a fact confirmed empirically.

This is typical electrostatic coating, where the current flowing between the positive and negative electrodes is only 20-50 microamperes, very small. Therefore, even objects with high electrical resistance, like wood, can be electrostatically coated.

Electrostatic spray guns

The electrostatic spray gun is a core piece of equipment in the industrial coating field. Based on the principle of electric field adsorption, it efficiently sprays paint onto the workpiece surface, primarily used for surface treatment of metals, wood, plastics, automotive parts, and aerospace. It uses a high-voltage electrostatic field to orient charged paint particles to the grounded workpiece. The operating voltage is typically 50-60KV, and a spraying distance of 100-300mm is recommended to balance coating quality and efficiency.

The equipment is available in manual and automatic types, and according to paint form, it can be divided into liquid and powder spray guns. Feeding methods include pressure feeding and gravity feeding. Typical configurations include an electrostatic generator, atomizing nozzles and control system. Some models integrate constant flow regulation and rotary vulcanization functions to improve the uniformity of coating adhesion. Compared with traditional spraying technology, electrostatic adsorption can reduce coating loss by more than 30% and supports automated integration. For example, CNC intelligent spray guns can achieve precise operation through telescopic mechanism and limit system. Maintenance requires regular cleaning of nozzles, lubrication of moving parts and replacement of seals.

Manual electrostatic spray gun

Automatic electrostatic spray gun:

According to the applicable paint, electrostatic spray guns can be divided into powder electrostatic spray guns and liquid electrostatic spray guns.

Electrostatic Powder Spray Gun

The electrostatic spray gun mainly consists of a powder supply tank, a spray gun, and a controller.

Powder Supply Tank: Durable, with excellent fluidization and a smooth appearance, made with imported microporous plates for superior flow and no powder spikes, resulting in more uniform powder output. Stainless steel powder tanks are used in electrostatic powder coating machines; the bottom is removable, and the fluidization plate is detachable for easy color changes. Centralized powder supply tanks for electrostatic spraying are mainly used in powder coating production lines and can be customized according to actual needs. They can be equipped with 4-8 powder pumps for excellent fluidization and concentrated powder output.

Spray Gun: The electrostatic spray gun incorporates foreign technology. The gun body is injection molded, making it lightweight and aesthetically pleasing. It employs a secondary pressure boosting technology, achieving 24 pressure multipliers and a strong electrostatic field. A rotating air jet booster is attached to the front of the gun, resulting in a more ideal powder mist.

Controller: The electrostatic powder coating equipment controller includes an electrostatic generator, power controller, powder supply controller, and other control units. The electrostatic generator features a color grating display for voltage and current, short-circuit protection, constant current source control, and all imported circuitry. It utilizes a low-voltage input spray gun, making the control system safer.

Liquid Electrostatic Spray Gun:

Commonly known as an electrostatic paint spray gun, electrostatic oil spray gun, or electrostatic paint spray gun, it mainly consists of a nozzle, spray gun, electrostatic generator, and paint pump.

1. Nozzle: The atomizing device of the electrostatic spray gun. It consists of circular nozzles and fan-shaped nozzles, generally selected according to the type of paint and the object being coated.
2. Spray Gun: The spray gun’s construction principle is the same as a regular air spray gun. It has a simple structure but requires extremely high precision. It must use materials with extremely high requirements for corrosion resistance, wear resistance, and electric shock resistance to ensure a long service life. High-quality nozzles, spray caps, paint valves, and specially treated needles are used.
3. Electrostatic Generator: Also called the controller or main unit. It generates an electric field through a high-voltage module to achieve electrostatic spraying. 4. Paint pump: The paint supply system for electrostatic spray guns, serving as the power source for the paint.

Applications of Electrostatic Spray Guns

With the rapid development of electrostatic spray guns, they are now widely used in various industries. To achieve electrostatic spraying, it is essential that: both the paint and the substrate are conductors; and the paint’s resistance and viscosity must be within suitable ranges.

1. Metal protection and metal surface coating.
2. Wood surface coating.
3. Plastic surface coating.
4. Electroplating protection.
5. Aerospace industry.
6. Vehicle parts.

Using electrostatic spray guns can significantly improve the paint coverage and reduce paint waste. Whether considering paint savings, labor time savings, improved working conditions for spray painters, or improved coating quality and environmental protection, electrostatic spray gun coating technology has secured its important position.

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