The online spray painting and curing line is a highly automated industrial equipment used for spray painting various workpieces and subsequent curing processes to form a durable and aesthetically pleasing coating. Its workflow mainly consists of the following key steps:

1. Workpiece Loading

• Operation Method: Workers neatly place the workpieces to be painted on special tooling fixtures, which are then precisely installed on the hooks or carrying devices of the conveying system. This process requires ensuring that the workpieces are firmly fixed to prevent displacement or falling during subsequent conveying and painting processes, which could affect the painting quality and even cause equipment malfunctions.

• Application Scenario Example: In the automotive parts manufacturing industry, large - scale components such as car doors and hoods are fixed by specially designed large - scale tooling fixtures. For small electronic device casings, small and precise fixtures may be used to adapt to their size and shape characteristics.

2. Pretreatment Process

• Degreasing and Cleaning: Workpieces first enter the degreasing and cleaning area, where special degreasing agents are used to remove oil stains, greases, and other organic contaminants on the workpiece surface through methods such as spraying and soaking. For example, on the surface of metal workpieces, since cutting fluids and lubricants may remain during the processing, degreasing and cleaning are crucial steps to ensure the adhesion of the subsequent coating.

• Water Washing: After degreasing, the workpieces enter the water - washing area, where they are thoroughly rinsed with multiple passes of clean water through spraying or soaking to remove the residual degreasing agent on the surface. The water - washing process usually adopts a multi - stage counter - current rinsing process, which not only ensures the cleaning effect but also saves water.

• Surface Adjustment (Optional): For workpieces made of some special materials, surface adjustment treatment may be required. For example, before phosphating treatment, the metal surface is pretreated with a weakly alkaline solution to optimize the surface microstructure and make the subsequent phosphating film more uniform and dense.

• Drying: After water - washing, the workpieces enter the drying area, where hot - air circulation, infrared radiation, and other methods are used to quickly remove surface moisture, providing a dry workpiece surface for the painting process. For example, in furniture manufacturing, wooden workpieces need to be thoroughly dried after water - washing to prevent paint blistering and peeling.

3. Painting Process

• Painting Booth: Workpieces are smoothly transported into the painting booth by the conveying system. The painting booth is one of the core areas of the entire production line. The environment inside the painting booth is strictly controlled, and the temperature and humidity are maintained within a suitable range to ensure the painting effect. For example, when spraying car bodies, the temperature in the painting booth is usually controlled at 20 - 25 degrees Celsius, and the humidity is controlled at 40% - 60%.

• Painting Equipment: The booth is equipped with automated painting equipment such as spray guns and painting robots. The spray guns precisely control the paint spraying volume, spraying angle, and spraying speed according to the preset program. For example, for flat workpieces with regular shapes, reciprocating spray guns may be used for planar spraying. For workpieces with complex shapes, such as toy models, multi - axis painting robots may be used to achieve all - around and precise spraying.

• Paint Supply: The paint supply system transports the prepared paint to the spray guns through pipes. The paint supply system has precise flow control and pressure adjustment functions to ensure that the spray guns always receive a stable and appropriate paint supply, thus guaranteeing the consistency of the painting quality.

4. Leveling Process

• Leveling Area: After leaving the painting booth, the painted workpieces enter the leveling area. In the leveling area, under certain temperature and time conditions, the paint surface levels naturally by relying on the gravity and surface tension of the paint itself, reducing surface defects such as orange peel and sagging. For example, in furniture painting, the leveling process can make the paint surface smoother and improve the appearance texture of the furniture.

• Environmental Control: The leveling area usually controls a certain temperature and wind speed to optimize the leveling effect. Generally, the temperature is slightly higher than room temperature, and the wind speed is maintained at 0.3 - 0.5 meters per second, which can promote paint leveling without causing paint surface pollution or excessive drying.

5. Curing Process

• Curing Oven: The leveled workpieces enter the curing oven for curing treatment. The curing oven uses different heating methods, such as hot - air circulation heating, infrared heating, and ultraviolet curing, according to the paint type and workpiece material. For example, thermosetting paints usually use hot - air circulation curing. Through high - temperature, the resin components in the paint undergo a cross - linking reaction to form a hard and wear - resistant coating. Light - curing paints use ultraviolet radiation to achieve curing in a short time.

• Temperature and Time Control: During the curing process, precise control of the curing temperature and time is crucial. Different types of paints have different curing parameters. For example, the curing temperature of common epoxy paints may be between 150 - 200 degrees Celsius, and the curing time is 20 - 30 minutes. The curing temperature and time of acrylic paints are relatively lower.

• Waste Gas Treatment: Volatile organic compounds (VOCs) and other waste gases are generated during the curing process. The curing oven is equipped with waste gas treatment devices, such as activated carbon adsorption devices and catalytic combustion devices, to purify the waste gases and ensure that the emissions meet environmental protection standards.

6. Cooling Process

• Cooling Area: The workpieces coming out of the curing oven have a high temperature and need to enter the cooling area for cooling. The cooling methods usually include air cooling or water cooling to quickly reduce the workpiece temperature to room temperature for subsequent handling and inspection. For example, when cooling metal workpieces, air cooling can blow cold air to the workpiece surface through fans or blowers to achieve rapid cooling.

• Quality Protection: The cooling speed needs to be controlled during the cooling process to avoid stress deformation of the workpiece or coating cracking caused by excessive cooling speed. For workpieces with high requirements for dimensional accuracy, such as precision mechanical parts, the cooling conditions should be strictly controlled.

7. Workpiece Unloading

• Operation Process: The cooled workpieces reach the unloading area with the conveying system. Workers remove the workpieces from the tooling fixtures for subsequent packaging, storage, or entry into the next processing step. During this process, a preliminary visual inspection of the workpieces is required. If obvious coating defects are found, they should be recorded and marked in time.

• Application Scenario Example: In the electronics manufacturing industry, after the painted and cured mobile phone casings are unloaded, they will directly enter the assembly workshop for subsequent component assembly. In the building decoration industry, the painted and cured aluminum alloy door and window frames will be packaged and prepared for shipment to the construction site for installation.