Characteristics of electrostatic powder spraying

Since powder coating spraying technology entered the coating industry, the market share of powder coatings in general industrial coatings has continued to grow year by year. The reason is that powder spraying technology has unique advantages. As environmental protection laws have increasingly strict regulations on the content of organic volatile compounds (VOC) in the atmosphere, the coating industry has been trying to develop coating technologies that are gentler on the environment. After long-term research and experiments, it was discovered that "electrostatic powder spraying" ” is the cleanest painting technology currently available.

Powder coating does not use volatile solvents such as organic solvents and water. It is an inorganic solvent-based coating. This greatly reduces the pollution caused by solvents, including poisoning of operators due to the presence of organic solvents. It also does not cause poisoning due to organic solvents. And cause a fire. Since the advent of powder coatings, there have been no major safety accidents caused by powder coatings.

Powder coating is a coating with pure solid components. It can be sprayed completely automatically. A large amount of or over-sprayed powder can be easily collected by the recovery system for recycling and reuse. Therefore, the usage rate of powder coatings can reach almost 100%, allowing the coating industry to reduce waste disposal costs while minimizing environmental pollution. 1, pre-treatment purpose: to remove oil, dust, and rust on the surface of the workpiece, and to generate a layer of "phosphating layer" or "chromium layer" on the surface of the workpiece that resists corrosion and can increase the adhesion of the spray coating. Main process steps: oil removal, rust removal, phosphating (chromation), passivation. After pre-treatment, not only the surface of the workpiece is free of oil, rust, and dust, but also a uniform and rough gray phosphating film (chromized film) that is not easy to rust is formed on the original silver-white shiny surface, which can both prevent rust and It can increase the adhesion of the plastic spray layer. There are three common pre-treatment methods: immersion type, spray type, and waterfall type. The immersion type requires multiple soaking tanks; the spray type requires a spray line to be set up on the spraying line; the waterfall type means that the solution flows directly down the workpiece from a high place. 2. Electrostatic spraying Purpose: to spray the powder coating evenly on the surface of the work piece. A high-performance electrostatic spraying machine should be used for special work pieces (including locations where electrostatic shielding is prone to occur). Process steps: Use the principle of electrostatic adsorption to evenly spray a layer of powder coating on the surface of the workpiece; the fallen powder is recovered through the recovery system and can be reused after sieving. 3. Curing purpose: solidify the sprayed powder onto the surface of the workpiece . Process steps: Put the sprayed workpiece into a high temperature furnace of about 200°C for 20 minutes (the curing temperature and time are determined according to the quality of the selected powder. The curing temperature of the special low-temperature powder is about 160°C, which saves more energy). The powder is concentrated, leveled and solidified.