The common coating method of primer in automobile sheet metal painting

The good and bad of coating quality is the result of the comprehensive action of the three elements of coating, among which the correct selection of coating process is also an important aspect that affects the quality of coating. The choice of the so-called painting process, in a sense, is the choice of painting method, different painting methods are suitable for different conditions of painting, so the choice of the correct painting method is very important. Up to a certain point, the main coating methods are dip coating, spray coating, brush coating, roll coating, electrophoresis, scraping coating, electrostatic spraying, rubbing coating 8 kinds. Among them, electrophoresis, spraying, electrostatic spraying and scraping are widely used in automobile painting. The most common method in automobile repair painting is spraying.

1. Dip

Dip coating is a coating method in which the coated material is directly immersed in a large amount of liquid paint and the adhesion between the coating and the coated surface is used to make the coating adhere to the surface of the coated material. This painting method is more common in the early production process, and it is suitable for the painting of parts with small volume and low requirements for painting quality. Dip coating has lower requirements for production conditions and does not require the operator to have a higher technical level, but the waste of paint is more serious and the impact on the environment is greater.

2. Spraying

Spraying is a coating method that atomizes the paint with a special spraying equipment (mainly a spray gun) and paints it on the surface of the coated material. This painting method appeared late, its application range is very wide, most of the parts can be painted by spraying method. The spraying coating is relatively economical, the coating quality is good, and the coating quality is easy to control, but it has high requirements for the technical level of the operator, strict requirements for the spraying equipment, and serious impact on the environment.

3. Brush

Brush painting is the painting method of using a brush made of animal hair or plant fiber to brush the paint on the surface of the object. This coating method appeared earlier, but the application range is very wide. Brush coating has lower requirements for painting equipment, higher requirements for the technical level of the operator, less waste of paint in the coating process, and less impact on the surrounding environment.

4. Roll coating

Roll coating is a coating method in which a roller made of cotton or chemical fiber is uniformly coated on the surface of an object by rolling the roller wheel. This painting method is suitable for large-area painting, which has lower requirements for painting equipment, but higher requirements for the technical level of the operator, and less waste of paint.

5. Electrophoresis

Electrophoresis is to immerse the coated material in the paint, the coated material and the paint are charged with different polarity, using the principle of charge movement to paint the method. Electrophoretic coating has high requirements on the auxiliary equipment of coating, which is difficult in technology and has a high degree of automation. Electrophoretic coating can control the thickness of the coating film well, and the coating quality is high. It is often used for the coating of the bottom coating in the manufacture of new cars. Due to the difference of the charge added to the coated material, it can be divided into two kinds of cathode electrophoresis and anode electrophoresis.

6. Scrape and apply

Scraping is a coating method that uses a scraper to scrape the paint onto the surface of the coated object. Scraping has lower requirements for painting equipment, higher technical requirements for operators, and less paint waste. Scratch coating is mainly used for dent filling and shape repair in automobile repair painting.

7. Electrostatic spraying

Electrostatic spraying is a painting method that applies a certain voltage of electrostatic electricity to the spraying equipment, endowing the spraying coating with a certain voltage of electrostatic electricity, and applying the electrostatic adsorption principle to the coating surface. Electrostatic spraying has higher requirements for spraying equipment, but the technical level of the operator is lower, and the waste of paint is less, and the impact on the environment is less.

8. Rub and paint

Rub coating is the coating method of dipping cloth or other materials with paint and then rubbing the paint on the surface of the coated object. The application of rubbing is less, and it is generally used when you want to obtain some special effect. It has lower requirements for painting equipment, but higher requirements for the technical level of the operator.