When choosing spray guns for plastic spraying production lines, in addition to considering the general factors for selecting spray guns for common spraying production lines, it is also necessary to comprehensively consider the characteristics of plastic materials and the special requirements of plastic spraying. The following are some specific points:

Consider the Characteristics of Plastic Materials
Surface Tension: Different plastic materials have different surface tensions. For low-surface-energy plastics such as polytetrafluoroethylene, spray guns that can make the coating adhere and spread better should be selected. Spray guns with fine atomization effect and capable of generating appropriate static electricity can be chosen to improve the adhesion of the coating on low-surface-energy plastics by utilizing the electrostatic adsorption effect.

Heat Sensitivity: Some plastics are prone to deformation when heated. For such heat-sensitive plastics, spray guns that can control the spraying temperature and speed should be selected to avoid plastic deformation caused by the heat generated during the spraying process. For example, spray guns equipped with cooling devices or those that can control the paint output and spraying distance can be used to reduce heat accumulation.

Match the Characteristics of Coatings
Drying Speed: Coatings commonly used in plastic spraying, such as acrylic paint and polyurethane paint, have different drying speeds. For coatings with a fast drying speed, the atomization and spraying speed of the spray gun need to match them to prevent the coating from drying too quickly at the nozzle of the spray gun or on the plastic surface, which may lead to nozzle blockage or affect the quality of the coating. Spray guns that can evenly atomize and quickly disperse the coating into fine particles can be selected so that the coating can be evenly attached and dried in a short time.

Leveling Requirements: To obtain a smooth and flat plastic coating, the leveling property of the coating is very important. For coatings with good leveling properties, the spraying pressure and paint output of the spray gun should be moderate to avoid over-spraying that may cause sagging. For coatings with poor leveling properties, spray guns with better atomization effects are required so that the coating can spread more evenly on the plastic surface and promote leveling.

Meet the Requirements of Spraying Quality
Appearance Precision: Many plastic products are used in fields with high requirements for appearance, such as the casings of electronic products and toys. Spray guns that can achieve high-precision spraying are needed. Spray guns with fine atomization functions and capable of precisely controlling the spraying range and thickness should be selected, such as air spray guns or electrostatic spray guns with small nozzles. They can achieve precise spraying within a millimeter or even a smaller range and reduce burrs and overspray.

Color Uniformity: When performing multi-color spraying on plastics or when natural color transitions are required, spray guns that can accurately control the output and mixing of coatings are needed. Some spray guns with multiple channels or adjustable mixing ratios can better meet this requirement, ensuring that different colors of coatings are evenly mixed and transitioned during the spraying process.

Adapt to the Production Environment and Process
Environmental Protection Requirements: With the improvement of environmental protection requirements, water-based coatings or coatings with low volatile organic compounds (VOC) are increasingly used in plastic spraying production lines. At this time, spray guns suitable for the atomization and transmission of water-based coatings should be selected, such as those with anti-corrosion coatings and capable of adapting to the high surface tension of water-based coatings. Meanwhile, considering the matching of environmental protection equipment such as exhaust gas treatment systems, the spraying efficiency and coating utilization rate of spray guns will also affect the environmental protection cost and effect. Efficient spray guns can reduce coating waste and exhaust gas emissions.

Automation Degree: If the plastic spraying production line is highly automated, the spray guns need to closely cooperate with the automation equipment. Spray guns with good interfaces and compatibility and capable of receiving precise instructions from the automation control system should be selected, such as automatic electrostatic spray guns or robotic spray guns. These spray guns can spray according to preset programs and trajectories, ensuring the consistency and stability of the spraying quality.