There are five aspects of plastic spraying process:
1. Annealing: the plastic is easy to form internal stress during molding, and the stress concentration is easy to crack after coating. Annealing treatment or full face treatment can be used to eliminate stress. Annealing treatment is to heat the ABS plastic molding parts to below the thermal deformation temperature, that is, 60 ℃, and keep them for 2h. Since this process requires a large amount of equipment investment, the whole surface treatment technology can be used, that is, the solution that can eliminate the internal stress of the plastic part can be configured to treat the surface of the plastic part for 15-20 minutes at room temperature.
2. Degreasing: The surface of plastic parts is often stained with oil stain, sweat and release agent, which will make the adhesion of paint worse, and the coating will crack, blister and fall off. Oil removal treatment shall be carried out before painting. The plastic parts are usually cleaned with gasoline or alcohol, and then chemical degreasing. After chemical degreasing, the residual lye on the surface of the workpiece should be thoroughly cleaned, and finally cleaned with pure water, dried or dried.
3. De electrification and dedusting: plastic products are rigid bodies, and the surface resistance is generally about 1013 Ω, which is easy to generate static electricity. After electrification, it can easily absorb the fine dust in the air and attach to the surface. Because it is very difficult to remove the electrostatic adsorbed dust by general air blowing method, the effect of simultaneous removal of electrostatic precipitator by high-pressure ionized air flow is better.
4. Spraying: the thickness of plastic coating is 15-20 μ m, which usually requires 2-3 layers of spraying. The second spraying shall be carried out after the first spraying is dried for 15min. Clear paint must also be sprayed on the surface that needs to be bright. The coated parts have little effect on the flame retardancy.
5. Drying: after coating, it can be dried at room temperature or baked at 60 ℃ for 30min
