The development of painting production line in China has gone through the process from manual to automatic production line. The painting process in China can be simply summarized as: pretreatment spraying drying or curing three wastes treatment. China's painting industry really originated from the introduction of Soviet technology in the 1950s. Painting production lines have been established in some projects, but these production lines are usually composed of steel welded grooves and steel spray (painting) chambers and drying chambers (furnaces), which are operated manually by electric hoists (a small number of suspended conveyors). At that time, the pickling trough was usually steel plate lined with lead. With the development of the times, the trough lined with fiberglass reinforced plastics or all using fiberglass reinforced plastics appeared. Since the 1960s, due to the development of light industry, first of all, there have been mechanized production lines and automated production lines in the bicycle manufacturing industry, and on the basis of the original trough production line, the program-controlled production lines formed by adding program-controlled cars, which are mainly in Shanghai and Tianjin. During this period, the main task of China's painting industry is mainly anti-corrosion. However, with the development of economy in China and the development of painting technology abroad, through the introduction of technology and the exchange of technology with foreign countries, painting technology in China began to develop rapidly. In the field of painting automation production, the popularization and application of electrostatic spraying and electrophoretic painting technology, the development and popularization of powder spraying technology, especially in China. The vigorous development of household appliances industry, daily hardware, steel furniture, aluminium components, electrical products, automotive industry and other fields in motor assembly line has made obvious progress in the painting industry, and intelligent spraying robots have also appeared in the painting production line.

Motor assembly line

Technological development

As a pretreatment technology, the traditional way of the initial pretreatment is trough dipping, which is trough-by-trough dipping according to the technological process. With the improvement and development of motor painting line technology, two-in-one (oil removal, rust removal) and three-in-one (oil removal, rust removal, passivation) processes have emerged. Spray pretreatment is widely used in domestic and foreign household appliances industry. Its characteristics are high production efficiency, simple operation, easy to realize production automation or semi-automation, good degreasing effect, compact and uniform phosphating film. However, no matter how it develops, the pretreatment process of surface treatment is necessary. For different coating requirements and anti-corrosion requirements, oil removal, rust removal, phosphating and other treatment methods should depend on the status of the raw materials of the workpiece. Of course, in the pretreatment process, sand blasting, shot blasting or grinding process is also applied in different sectors of different industries according to needs. With the development of the times and the development of surface treatment technology, tap water is generally used in water washing at first, but with the development of technology requirements, distilled water or pure water has been used in water washing, and ultrasonic treatment technology has also been used in pretreatment.

Development of Spraying Technology

Since the 1980s, China began to introduce some spraying equipment or single equipment. Some spraying spraying spraying equipment abroad also began to digest, absorb and develop, such as cup spraying, water curtain spraying, water spinning paint removal and a series of spraying and spray treatment methods, which made the spraying technology a step forward, especially electrophoresis in the 1980s. Paint treatment technology. In the mid-1960s, when electrophoretic paint was first applied, nylon towels were used for paint treatment and ice bags were used for temperature control. With the advancement of the times, from 1980s to 1990s, a series of devices such as ultrafiltration have been developed for the treatment of electrophoretic bath solution.