Coating powder painting method - airspraying

The air spraying method is the earliest and most primitive coating method of powder coating. This coating method uses a Spray Gun as a tool, and sprays the removal material on the surface of the object that has been surface-treated and preheated to a certain temperature by means of the siphon effect of compressed air. At this time, the powder coating is melted and attached to the object to be painted, and then the object to be coated is heated in a general oven. The thermoplastic powder coating is sprayed, which only needs to be melted and leveled to form a flag; if the sprayed thermosetting powder coating is melted and leveled, it needs to be cross-linked and solidified to form a film. When using a simple manual gun, just put the powder coating into the cup and adjust the air pressure. The Spray Gun of the air coating method is shown in Figure 5-1. If the amount of powder used is large, the screw feeder or Venturi device shown in Figure 5_2 can be used. The thickness of the coating film is controlled by conditions such as the amount of powder coating sprayed, the time of powder call and the speed of the assembly line. This coating method has the following advantages:

1. set each structure to be simpler, and the investment of equipment is less.

②The spilled powder coating can be recycled and reused.

③Applicable to the coating of small objects to be coated.

④Aspirational powder coatings and thermosetting powder coatings are applicable.

⑤Two kinds of powder coatings with different characteristics can be sprayed after being mixed on site, and the coating film performance can be modified.

The disadvantage of this static installation method is that the object to be coated needs to be preheated, it is not suitable for large-scale objects, the thickness of the film is not easy to control, and the operation technology of hot practice is required, so the application is limited to a certain extent.