The secrets of the four major processes of automobile manufacturing
Cars are the product of modern industry, and they drive us around the world every day. With the advancement of technology and the development of industrial level, automobiles are becoming more and more advanced, integrating various high technologies. You may sometimes wonder: How are cars produced?
The process work of the automobile manufacturing industry mainly includes stamping process, welding process, painting process, and assembly process, which are commonly known as the "four major processes" of automobiles.
1. Stamping process
Stamping is the first step in all processes, and each workpiece generally needs to be completed through several processes. Stamping is realized by stamping machine tools and molds. Stamping three elements: plate, mold, equipment.
(1) Stamping sheet
Generally, low-carbon steel is used, and the skeleton and cover parts of the body are mostly stamped with steel plates. The special steel plate for the body has the characteristics that cracks are not easy to occur when deep drawing is delayed. According to the different positions of the body, some parts to prevent rust use galvanized steel plates, such as fenders, roof covers, etc.; some parts that are subject to greater stress use high-strength steel plates, such as radiator support beams, upper side beams, etc. The thickness of steel plates commonly used in car body structures is 0.6-3 mm, the thickness of most outer plates is generally 0.6-0.8 mm, the thickness of inner plates is generally 1.0-1.8 mm, and the thickness of reinforcement plates is generally 2.0-2.5 mm.
(2) Stamping die
In modern industrial production, the mold is an important process equipment for the production of various industrial products. It shapes the raw materials in a certain way with its specific shape. In the automobile industry, among various types of automobiles, an average model needs about 2,000 sets of stamping dies, including nearly 300 sets of large and medium-sized panel dies. Mold has become an important means of contemporary industrial production and one of the development directions of technology. The development of varieties of modern industrial products and the improvement of production efficiency depend to a large extent on the development and technical level of molds. At present, molds have become one of the important symbols to measure a country's manufacturing level.
(3) Stamping equipment
At present, the domestically produced large stamping lines for the manufacture of large car panels have reached the contemporary international advanced level. In order to meet the needs of the automatic stamping production line, well-known domestic press manufacturers have carried out the development and production of high-performance stand-alone presses. We have successively developed stamping equipment with large tonnage, large stroke, large table, large tonnage air cushion, automatic manipulator loading and unloading system, automatic mold changing system and fully functional touch screen monitoring system, fast production speed and high precision. These stand-alone connection equipment have been equipped with many large-scale automatic stamping production lines of domestic large-scale automobile manufacturers, and are expanding to more automobile factories and foreign companies, fully meeting the requirements of fast, high-precision and high-efficiency automobile production.
2. Welding process
The stamped body panels are partially heated or heated and pressed together to form a body assembly. The most widely used in the manufacture of automobile bodies is spot welding. Spot welding is suitable for welding thin steel plates. During operation, two electrodes apply pressure to two steel plates to make them stick together, and at the same time, the bonding point is heated and melted by electric current, so as to firmly join. Welding the entire car body usually requires thousands of welds. The strength requirements of the solder joints are very high, and each solder joint can withstand a tensile force of 5kN, even if the steel plate is torn, the solder joints cannot be separated. In addition, a large number of riveting methods are used to process the body.
Commonly used welding methods for welding:
(1) Spot welding: mainly used for welding of body assembly, floor, door, side wall, rear wall, front axle and small parts. (belonging to resistance welding)
(2) CO2 shielded welding: used for welding carriages, rear axles, frames, shock absorber valve stems, beams, rear axle casing tubes, drive shafts, hydraulic cylinders and jacks. (belonging to arc welding)
(3) Projection welding: used for welding nuts and face bolts. (belonging to resistance welding)
(4) Stud welding: used for welding of end studs. (belonging to arc welding
3. Coating process
Coating has two important functions for automobile manufacturing. The first is to prevent corrosion of automobiles, and the second is to add beauty to automobiles. The coating process is relatively complicated and the technical requirements are relatively high. There are mainly the following processes: pre-painting pretreatment and primer, painting process, drying process, etc. The whole process requires a large amount of chemical reagent treatment and fine process parameter control, and has high requirements for paint materials and various processing equipment.
4. Assembly process
Final assembly is the process of assembling the car body, engine, transmission, instrument panel, lights, doors and other parts that make up the whole car to produce the whole car.
(1) The general assembly workshop mainly has four major modules, namely the front wall assembly module, the instrument panel assembly module, the lamp assembly module, and the chassis assembly module. After the assembly of each module and the installation of each component, the whole vehicle can be rolled off the assembly line after the inspection and adjustment of wheel alignment and headlight field of view detection.
(2) Automobile assembly line
The mechanized production line system of automobile manufacturing final assembly includes vehicle assembly line (process chain, driven by multiple electric motors), body conveyor line, storage line, elevator, etc. The automobile assembly line is generally an organic whole composed of conveying equipment (air suspension and ground) and professional equipment (such as lifting, turning, pressing, heating or cooling, testing, bolt and nut fastening equipment, etc.).