Four major process types in automobile manufacturing

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  Technology refers to the economic and scientific process and method of processing raw materials into production means and commodities. As an automotive engineer, it is very necessary to understand the four major processes of vehicle manufacturing. For a complete vehicle, process work and product design are closely related and complementary to each other. If technology is separated from design, it will inevitably cause waste; if design is separated from technology, the product will be meaningless. Generally speaking, the four major processes of vehicle manufacturing are: stamping, welding, painting, and final assembly.


  Stamping is the process of stamping and forming sheet metal parts using molds according to design requirements. The stamping process occupies an important position in the automobile manufacturing process and is the first step in vehicle manufacturing. At present, most automobile bodies are made of steel plates and alloys. They are stamped to form the shape desired by the designer. Stamped parts include: left/right front fender, left/right outer panel, rear side panel (left/right rear fender), four doors, top cover, trunk panel, floor, front wall panel, etc. .

  Three elements of stamping: stamping equipment, stamping molds, and stamping plates.

  Stamping equipment is the so-called stamping machine, which can perform cutting, punching, bending, riveting, forming and other operations. The selection of stamping equipment is generally based on production quantity, equipment size, etc. Generally speaking, the stamping equipment of automobile manufacturers is divided into 2500 tons, 2000 tons, 1600 tons, 1000 tons, 800 tons, 500 tons, etc.

  Stamping dies are an important part of the production of various industrial products. They shape raw materials into specific shapes. Molds have become an important indicator of the development of modern industry and one of the important indicators of a country's manufacturing level. Stamping molds can be divided into four basic units: punching, bending, drawing, and forming. According to the degree of process combination, it can also be divided into single-process mold, composite mold, continuous mold, etc. When considering cost factors during the design stage, we should try to open as few molds as possible. Changes and modifications to molds need to be recorded to prevent unnecessary trouble.

  Stamping plates: The car body is generally made of low carbon steel. The frame and covering parts of the car body are mostly made of stamped steel plates. The special steel plates for the car body have the characteristics of being difficult to produce cracks during deep drawing. Depending on the location of the car body, multiple galvanized steel sheets are used in rust-prone areas, such as fenders, roofs, etc. High-strength steel plates are used in some parts that bear greater stress, such as radiator support beams, upper side beams, B-pillars, etc. Commonly used steel plates for car body structures have a thickness of 0.6mm~3mm, and most parts use a thickness of 0.8mm~1.0mm.

  The stamped sheet metal parts are welded to form the body in white. In fact, the entire body structure is made up of stamped parts welded together. If the welding quality is not up to standard, it may cause the body sheet metal to deform and crack, produce abnormal noise, and seriously affect personal safety. The welding workshop is generally connected with the stamping workshop to facilitate material transportation. The welding process generally uses resistance welding, carbon dioxide shielded welding, etc. According to statistics, a complete vehicle has a total of 5,000-6,000 welding points.

  Welding fixtures play a role in supporting, assembling, and fixing in the welding workshop. Basically all welding parts require fixtures to ensure the correct assembly relationship, geometric size, and shape, and at the same time, they can also improve work efficiency.

  The environment of the welding workshop is harsh, with loud noise, poor air quality, certain dangers (large welding current can reach thousands of amperes), and high labor intensity. Welding workshop workers are required to wear masks, gloves (wire gloves + anti-cut gloves + half leather gloves), labor protection shoes, aprons, safety helmets and other labor protection supplies. With the development of science and technology, better welding workshops of automobile manufacturers can already achieve 90% mechanization and automation.


  Painting refers to spraying a layer of special paint on automobile sheet metal parts to protect the metal and provide beautiful decoration. The coating process is relatively complex and has high environmental requirements. It mainly includes the following processes: pre-painting pre-treatment and primer, spray painting process, drying process, etc. The whole process requires a certain amount of chemical reagent settings and detailed process parameter restrictions, and has high requirements for paint and various processing and development. , the coating process is generally confidential information of each company.

  For the painting of automobile bodies, it must be used in various weather conditions for a long time without causing paint film, deterioration and rust, and it must also be able to maintain its luster, color and appearance. The general car body painting process is electrophoretic primer, mid-coat, and topcoat. If there is a weld between the electrophoretic primer and the intermediate coating, sealing and bottom plate protective coating spraying are required to ensure the sealing, noise reduction and rust prevention of the car body.

  Final assembly

  Final assembly is the process of assembling various components onto the body-in-white. Because there are many parts to be assembled, the process is complex, and the parts have different shapes, it is impossible to achieve mechanization and automation. Therefore, the final assembly is a workshop with many employees and many workstations in the four major process workshops. Generally speaking, according to the assembly content, the general assembly workshop can be divided into: interior line, chassis line, assembly line, engine line, four-door line, instrument line, battery pack line, functional line, rain shower line, quality door, etc. Each line body is responsible for its own different work content, and finally all the parts are brought together, and after adding and programming, they are assembled into a qualified car.