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Lean optimization design of process equipment for cathodic electrophoretic coating equipment in coating equipment industry

In 1977, the world's first automotive body cathodic electrophoretic coating equipment was put into production in the United States, and automotive painting entered the era of cathodic electrophoresis. Based on CED coating film, it has excellent corrosion resistance, good throwing power, and can double the service life of automobile body (no perforation corrosion for 10 to 12 years). Popularization of cathodic electrophoretic coating technology in automobile industry The rate and popularity rate is unprecedented. In less than 10 years, the cathodic electrophoresis rate of automobile bodies is over 90%. During the “Sixth Five-Year Plan” period, Shenyang and Beijing Paint Factory introduced cathodic electrophoretic coatings. Under the organization of China National Automobile Corporation, FAW, Second Automobile and Jiqi introduced three cab cathodic electrophoresis coating lines and related coating technologies. After July 1986, they were put into production successively, forming a cathodic electrophoretic coating to replace the primer electrophoresis, dip coating and spray coating processes. The new body coating lines all adopt cathodic electrophoretic coating process.

More than 30 years of cathodic electrophoretic coatings and electrophoretic coating equipment have been continuously improved and improved, such as corrosion resistance, swimming penetration, environmental protection and other aspects have been greatly improved. Cathodic electrophoretic coating equipment has become a tried and mature automotive body primer coating technology. In 2009, China became the world's largest automobile production country; tens of millions of vehicles, except for some of the buses and modified cars, used a cathodic electrophoretic primer process. The CED coating process is still the advanced primer coating process for automotive bodies, and there is no ideal process to replace it.

Cathodic electrophoretic coating equipment is also widely used in the coating of automotive parts (such as frame, wheels, small and medium-sized sheet metal parts, shock absorbers, wipers, carriages and metal parts), in other industrial coating fields (such as building materials). , light industry, agricultural machinery, military, household appliances and other metal parts coating field) has also been popularized and promoted.

Some people think that "the process of electrophoretic coating equipment has been developed and applied for a long time, and there are not many places for improvement." The author holds different views based on the following situations, and believes that there is still a lot of room for improvement and innovation of cathodic electrophoretic coating technology. Regulations based on national environmental protection, cleaner production, and energy conservation and emission reduction have been promulgated, requiring cathodic electrophoretic coating processes to be more environmentally friendly (low VOC, low carbon, and harmless).

Shortage of resources, rising prices of raw materials, fierce competition in the automotive market, on the basis of ensuring the quality of coating, relying on technological advancement, improving and perfecting CED electrophoretic coating equipment , reducing CED coating costs and improving product competitiveness. Adjacent related technological advances and maturity (such as ED-RO, heat pump technology, new CED coatings, etc.), mutual promotion, need to replace, eliminate backward processes and equipment and paint updates.

In addition, the author found in the technical consultation and on-site technical service that the designer's understanding of the cathodic electrophoretic coating process is not in place, there are some misunderstandings, and the ability to flexibly apply related technologies and lean design according to the working conditions and the properties of the coated articles. It is limited to the pirated design, resulting in backward design of process equipment and high investment operation cost.

This article discusses how to rely on technological advancement to improve resource utilization, reduce CED coating costs, lean design of CED processes/equipment, and correct some misunderstandings, and discuss with readers.

1. Further understanding of the principles, processes and flexible application of cathodic electrophoretic coating equipment. The principle of CDE electrophoretic coating: 1) the pH rises due to the electrolysis of water near the surface of the coated object; 2) the paint particles lose their charge from the solution. Precipitation and precipitation form a coating film; 3) Electrophoretic coating process is accompanied by physical and chemical effects such as electrolysis, electrophoresis, electrodeposition (coagulation), electroosmosis. CED coating process and equipment designers can only understand and understand the CED coating principle, physicochemical effects of electrolysis, electrophoresis, electrodeposition (coagulation), electroosmosis, etc. in the coating process and the following related technologies (parameters). Flexibly apply relevant technologies and lay the foundation for lean design (basic skills).