Powder coating is a surface treatment method in which plastic powder is sprayed onto a part. Spraying is also the electrostatic powder coating coating that we often talk about. The processing technology is a kind of metal surface treatment decoration technology which has been widely used in the world since the 1980s. Compared with the general surface treatment of ordinary paints, the advantages are reflected in the advanced technology, energy saving and high efficiency, safety and reliability, and bright color. Therefore, it is often used in the field of light industry and home decoration. The working principle is that the plastic powder is charged by the high-voltage electrostatic device, and under the action of the electric field, the paint is sprayed onto the surface of the workpiece, and the powder is uniformly adsorbed on the surface of the workpiece to form a powder coating; and the powder coating passes through After high temperature baking, the leveling solidifies, and the plastic particles will melt into a layer of dense final protective coating with different effects; firmly attached to the surface of the workpiece.
No need to thinner, the construction is environmentally friendly, non-toxic to the human body; the coating has excellent appearance quality, strong adhesion and mechanical strength; the coating construction curing time is short; the coating has high corrosion resistance and wear resistance; no primer is needed; The construction is simple, the technical requirements for the workers are low; the cost is lower than the painting process; some construction occasions have clearly stated that the electrostatic spray process must be used; the common flow phenomenon in the painting process does not occur during the electrostatic spray coating process.
Purpose: To remove the oil, dust and rust on the surface of the workpiece, and to form a "phosphating layer" on the surface of the workpiece that is corrosion-resistant and can increase the adhesion of the spray coating.
Main process steps: degreasing, descaling, phosphating, passivation. After pre-treatment, the workpiece not only has no oil, rust and dust on the surface, but also produces a uniform and rough gray phosphating film which is not easy to rust on the silver-white shiny surface, which can prevent rust and increase the spray coating. Adhesion.
2, electrostatic spraying
Purpose: Spray the powder coating evenly onto the surface of the workpiece. Special workpieces (including locations where electrostatic shielding is easy to occur) should be sprayed with a high-performance electrostatic sprayer.
Using a static adsorption principle, a layer of powder coating is evenly sprayed on the surface of the workpiece;
The dropped powder is recovered by a recovery system and can be reused after sieving.
3, high temperature curing
Purpose: To heat the powder coating on the surface of the workpiece to the specified temperature and keep it for the corresponding time to melt, level and solidify, so as to get the surface effect of the workpiece we want.
Process steps: Push the sprayed workpiece into the curing oven, heat it to a predetermined temperature (typically 185 degrees), and keep it for the corresponding time (15 minutes); Generally, the workpieces are different, and the heating temperature and the holding time are also different.
Tip: heating and control system (including electric heating, fuel, gas, coal and other heating methods) + insulation box = curing oven.
4, the furnace cooling
Outlet cooling is a process in which the result of the spray process is cooled to return it to normal temperature.
5, decorative treatment
Purpose: To achieve a special appearance of the workpiece after electrostatic spraying, such as: various wood grain, pattern, lightening and so on.
Process steps: cover light; transfer and other processing techniques.