Spray Particle Size Control of High-Voltage Power Supplies in Electrostatic Spraying

In the electrostatic spraying process, the precise control of the spray particle size plays a decisive role in the quality of the coating. As the core component of the electrostatic spraying system, the output characteristics of the high-voltage power supply have a close and complex relationship with the spray particle size. In-depth exploration of this relationship is of great significance for optimizing the electrostatic spraying process and improving the performance of product coatings.
The basic principle of electrostatic spraying is to use a high-voltage power supply to establish a strong electric field between the spray gun and the workpiece, causing the sprayed coating droplets to be charged. Under the action of the electric field force, the charged droplets fly directionally towards the surface of the workpiece to achieve uniform coating coverage. The size of the spray particle directly affects key performance indicators such as the smoothness, adhesion, and film thickness uniformity of the coating.
The output voltage of the high-voltage power supply is one of the key factors affecting the spray particle size. When the voltage is low, the electric field strength is weak, and the electric field force on the coating droplets is small, making it difficult to overcome the restraint of surface tension. As a result, the droplets are not broken up sufficiently, and the formed spray particle size is large. As the voltage gradually increases, the electric field strength increases, and the electric field force on the droplets increases, promoting further fragmentation and refinement of the droplets, and the spray particle size decreases accordingly. However, when the voltage is too high, abnormal phenomena such as corona discharge may occur, which not only affects the spraying effect but also may cause equipment damage. Therefore, accurately controlling the output voltage of the high-voltage power supply is the basis for achieving the ideal spray particle size.
In addition to the voltage, the current characteristics of the high-voltage power supply also have an important impact on the control of the spray particle size. The current reflects the amount of charge passing through per unit time, and the charge amount of the coating droplets is closely related to the current. An appropriate current can make the coating droplets carry an appropriate amount of charge, fly stably in the electric field, and achieve a good particle size distribution. If the current is too small, the droplets are insufficiently charged and difficult to disperse effectively under the action of the electric field force, easily forming a spray with a large particle size. If the current is too large, the droplets may be overcharged, and the mutual repulsion effect increases, resulting in problems such as spray scattering and unevenness, which is also not conducive to obtaining an ideal particle size distribution.
Furthermore, the stability of the high-voltage power supply is crucial for the consistency of the spray particle size. If the output of the high-voltage power supply is unstable, with voltage fluctuations or current drifts, the electric field force and charge amount on the coating droplets at different times will change, causing fluctuations in the spray particle size and seriously affecting the uniformity of the coating quality. For example, during the electrostatic spraying of automobile bodies, if the spray particle size is unstable, the coating thickness on various parts of the body may be inconsistent, affecting the aesthetics and protective performance.
To achieve precise control of the spray particle size, when selecting and using the high-voltage power supply for electrostatic spraying, multiple factors such as voltage, current, and stability need to be comprehensively considered. By optimizing the design and parameter settings of the high-voltage power supply and combining with specific spraying process requirements, the spray particle size can be effectively controlled, providing a strong guarantee for the production of high-quality coating products.