Hand board surface treatment process ⑦: Painting

Painting is the general name of surface coating processing of industrial products. Painting processing is generally used for plastic Painting, silk screen printing and pad printing processing; Color modification and silk screen printing of EVA, rubber and other shoe materials. An injector is required to complete the process operation. You can choose oil spray matte, semi matte, high gloss, etc. according to your needs.

Why Painting?

The Painting on the surface of the hand board can make it more beautiful. To some extent, the Painting effect reaches the extreme, which can make consumers have a better visual impact and promote consumption. Moreover, Painting has a certain protective effect on the hand board and products. Take metal surface painting as an example. Metal surface painting is a method to protect metal from oxidation and corrosion. Good paint coating protection layer keeps continuous, intact and well combined, which can become a barrier to inhibit the invasion of corrosive media.

There are five processing steps for Painting:

1. Annealing: it is easy to form internal stress during plastic forming, and it is easy to crack at the stress concentration after coating. Annealing treatment or finishing treatment can be used to eliminate stress. Annealing treatment is to heat the ABS plastic molded parts to below the thermal deformation temperature, i.e. 60 ℃ for 2h. Because this process requires a lot of equipment investment, the whole surface treatment technology can be adopted, 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 15-20min at room temperature.

2. Degreasing: the surface of plastic parts is often contaminated with oil, hand sweat and release agent, which will deteriorate the adhesion of the coating and cause cracking, blistering and falling off of the coating. Degreasing treatment shall be carried out before coating. Plastic parts are usually cleaned with gasoline or alcohol, and then subject to chemical degreasing. After chemical degreasing, the residual lye on the surface of the workpiece shall be thoroughly cleaned, and finally cleaned with pure water, dried or dried.

3. Electric and dust removal: plastic products are insulators, and the surface resistance is generally about 1013 Ω, which is easy to generate static electricity. After charging, it is easy to adsorb the fine dust in the air and adhere to the surface. Because it is very difficult to remove the electrostatic adsorbed dust by general blowing method, the effect of using high-pressure ionized air flow to remove electrostatic precipitator at the same time is better.

4. Spraying: the thickness of plastic coating is 15 ~ 20 μ m. It usually takes 2 ~ 3 coats of spraying to complete. Dry for 15min after one spraying, and then conduct the second spraying. The surface that needs to be bright must also be sprayed with transparent paint. The coated parts have no effect on the flame retardant performance.

5. Drying: generally, the paint is baked at 150-180 ℃ for about 20-30 minutes; Bake the plastic paint at 60-80 ℃ for about 20-30 minutes; Some special paints can dry themselves in the greenhouse.