The spraying stage is the core link of the automatic reciprocating machine powder coating production line, and the main task of this stage is to spray the powder coating evenly and efficiently onto the surface of the workpiece, forming a stable and uniform coating.
1. Spraying equipment and spray gun
In the spraying stage, powder coating guns and automatic reciprocating sprayers are mainly used. The spray gun delivers powder coating to the surface of the workpiece and attaches the powder to the surface by corona discharge or friction. The automatic reciprocating machine is responsible for controlling the movement trajectory of the spray gun and the spraying method.
Spray Gun: The powder coating is delivered and accelerated by compressed air in the spray gun to ensure that the coating adheres evenly and quickly to the surface of the workpiece. The gun’s corona discharge technology charges the powder coating, allowing it to adsorb onto the workpiece.
Automatic Reciprocating Machine: The spraying gun is mounted on the automatic reciprocating machine, which controls the movement of the spray gun back and forth on the surface of the workpiece through preset paths (such as vertical, horizontal, beveled, etc.), ensuring that the powder is coated uniformly across the board.
2. Corona spraying principle
During the spraying process, the powder coating is attached to the surface of the workpiece through the corona spraying principle. The specific process is as follows:
Corona discharge: The spraying gun generates corona discharge from the nozzle through a high-voltage power supply, and the powder coating is charged with an electric charge. Since the workpiece is usually grounded or connected to the ground by electrodes, the charged powder coating is attracted to the surface of the workpiece.
Powder adsorption: The charged powder is ejected through the nozzle and adheres evenly to the surface of the workpiece. During spraying, the electrostatic force generated by corona discharge ensures that the powder coating adheres firmly to the surface of the workpiece, thus avoiding powder scattering and reducing waste.
The advantage of the corona spraying principle is that it can provide a uniform coating effect while avoiding the dripping and sagging problems of traditional liquid coatings.
3. The motion principle of the automatic reciprocating machine
The automatic reciprocating machine plays a crucial role in the powder coating process. Its primary function is to control the gun movement according to a preset trajectory and speed, ensuring that every surface of the workpiece is evenly covered with the coating. The specific process is as follows:
Reciprocating motion: The automatic reciprocating machine moves back and forth along the surface of the workpiece according to a preset path (such as horizontal, vertical, bevel, curve, etc.). The gun is sprayed back and forth with the movement of the reciprocating machine, ensuring that the powder coating covers the entire workpiece evenly.
Trajectory Adjustment: The motion trajectory of the reciprocating machine can be flexibly adjusted according to the shape, size, and coating requirements of the workpiece. For example, for larger workpieces, the reciprocating machine can make a long movement distance; For workpieces with complex shapes or small sizes, the reciprocating machine’s motion trajectory will be finer to ensure the uniformity and accuracy of the coating.
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Spraying speed and pressure control: The reciprocating machine can also adjust the movement speed and spraying pressure of the spray gun, which helps control the amount of powder coating deposition and coating thickness, thereby ensuring the uniformity and quality of the coating.
With the precise control of the reciprocating machine, the spraying process greatly improves production efficiency and ensures that each workpiece is evenly coated.

4. Automated Control of Spraying Parameters
In fully automated systems, various spraying parameters such as the amount of coating, spraying speed, and the distance of the spray gun can be precisely controlled through the automation system. Optimizing these parameters is key to ensuring coating quality:
Spray powder amount control: By controlling the amount of powder coating sprayed, the coating thickness can be kept uniform. Too much powder can result in excessive coating or waste, while too little may lead to uneven or incomplete coverage.
Spray gun speed control: The movement speed of the spray gun is controlled based on the size and shape of the workpiece. If the speed is too fast, the coating may be thin and uneven; if too slow, the coating may be thick and irregular.
Spraying distance control: The distance between the spray gun and the surface of the workpiece should be maintained appropriately. Too close can cause excessive thickness, while too far may result in uneven coating.
These spraying parameters are precisely adjusted by a fully automated control system to ensure that each workpiece achieves the desired coating effect.

5. Quality Monitoring During the Spraying Process
In the automated reciprocating powder coating process, quality monitoring is crucial to ensure coating performance and production efficiency. The system typically includes real-time monitoring and feedback mechanisms:
Real-time monitoring: With built-in sensors and cameras, the system can monitor the spraying process in real time, detecting abnormalities (such as insufficient spray amount or spray gun blockage) and making automatic adjustments.
Coating thickness measurement: Sensors or detection devices measure the coating thickness in real time to ensure that each workpiece meets the design requirements.
Surface defect detection: After the coating is applied, the automated inspection system checks for uniformity, adhesion, and surface defects such as bubbles and runs to ensure each workpiece meets quality standards.
The spraying stage of fully automated reciprocating powder coating, combined with corona spraying technology, precise movement of the automatic reciprocator, optimized control by smart systems, and strict quality monitoring, ensures high-quality and uniform powder coatings. The spraying process not only improves production efficiency but also significantly reduces human intervention, meeting the demands for efficient and high-quality manufacturing.
Through precise control and optimization, the spraying stage can provide ideal coating results for workpieces of various shapes and sizes, widely applied in industries such as automotive, appliances, elektronika, en meubels.