Views: 53 Author: Site Editor Publish Time: 2023-02-09 Origin: Site
Characteristics of powder coating:
(1) The coating thickness of 100 ~ 300μm can be obtained by powder coating once, while the use of ordinary coating requires 4 ~ 8 times of construction, improve the construction efficiency and shorten the production cycle.
(2) the coating does not contain solvents, without dilution and adjustment of viscosity, improve working conditions and reduce the risk of fire, conducive to the protection of the environment.
(3) Improve the adhesion and compactness of the coating, metal powder, ceramic powder and other mixed coating, more can improve the mechanical and physical properties of the coating, the corrosion resistance of the coating greatly improved.
(4) High degree of mechanization, and can recycle excessive paint, reduce the consumption of paint.
(5) The coating equipment is complex, the investment cost is high, the appearance and leveling of the coating is not as good as the spraying method, and some powder coating methods have requirements on the shape and size of the workpiece. Can only apply to powder coating, high cost.
The construction methods of powder coating have been obtained for industrial application: flame spraying method (fusion method), fluidized bed method, electrostatic powder spraying method, electrostatic fluidized bed method, electrostatic powder oscillation method, powder electrophoretic coating method, etc.
Fluidized bed powder coating process, because the workpiece is preheated to the powder melting point and coated, the viscosity of the melted polymer is reduced, the adhesion of the coating is greatly improved, the insulation and corrosion resistance of the coating are greatly improved. Insoluble resins such as nylon, polyethylene, polypropylene, etc., can also be constructed with this method.
(1) Workpiece cleaning workpiece must remove oil and rust. The workpiece immersed in gasoline or trichloroethylene vapor to remove oil; Sand blast or shot blasting to remove rust and clean up.
(2) The preheating temperature of the workpiece should be higher than the melting temperature of powder coating about 20℃, according to the size of the workpiece and the variety and thickness of the coating, the preheating range in 170 ~ 220℃.
(3) The parts of the covered workpiece that do not need to be coated can be protected by fixtures (such as silicone rubber), which play the dual role of clamping and protecting the workpiece.
(4) coating the workpiece into the fluidized bed, in order to obtain uniform and continuous coating, the workpiece dip once out, immediately reverse 180°, after coating melting and then dip coating, immediately reverse 180°. Dipping time is 1 ~ 2 seconds.
(5) after heat curing in order to make the coating on the workpiece better curing film, should enter the drying room again heating. The curing temperature and curing time are determined by obtaining the best coating performance and minimizing the construction period. For example, the curing temperature of epoxy powder coating is 180 ~ 190℃, and the curing time is 40 ~ 50 minutes.