Understanding the process of automotive metal stamping production

Stamping is the leading process in the automotive manufacturing process. The automobile stamping workshop undertakes the storage of raw materials, coils and sheets; the unwinding and shearing of the coils; the shearing of the sheets; the stamping production of large, medium and small stamping parts of various models; the storage of stamping parts; the disposal of waste materials and equipment, molds Daily maintenance and maintenance tasks. First, the stamping workshop process Raw materials (sheets and coils) storage → unwinding line → large-piece cleaning and oiling, small-piece unwinding and shearing → stamping production line → installation of mold debugging first qualified → put into mass production → qualified parts anti-rust → storage Second, the concept and characteristics of cold stamping 1. Cold stamping refers to a pressure processing method in which a material is applied at a normal temperature by applying a pressure to a material by a die mounted on a press to cause separation or plastic deformation. 2. Features of cold stamping: stable product size, high precision, light weight, good rigidity, good interchangeability, high efficiency and low consumption, simple operation and easy automation. Third, the classification of the basic process of cold stamping Cold stamping is generally divided into two categories: forming and separating. 1. The forming process is a stamping in which a blank is plastically deformed without breaking, to obtain a shape and size. The forming process is divided into: drawing, bending, flanging, shaping, and the like. Drawing: A stamping process in which a flat blank (process member) is changed into an open hollow member by a drawing die. Bending: A stamping method in which a sheet, a profile, a pipe, or a bar is bent at a certain angle and a certain curvature forms a certain shape. Flanging: A stamping forming method for turning a sheet into a vertical edge along a certain curvature on a flat portion or a curved portion of a blank. 2. The separation process is to form a stamping of a certain shape, size and cut surface quality by separating the sheets according to a certain contour line. Separation process points: blanking, punching, chamfering, trimming, etc. Blanking: When the materials are separated from each other along the closed curve, and the part inside the closed curve is used as the blanking member, it is called blanking. Punching: Separating materials from each other along a closed curve. When a portion other than the closed curve is used as a blank, it is called punching. Fourth, the name of each process and its code Some of the parts produced in the press shop belong to the cover parts, such as the outer cover of the engine cover, the top cover, and the door. Fifth, the requirements for the cover 1. Dimensions and shapes shall be in accordance with the test piece and the sample that is matched by the welded fitting. 2. The surface quality is good. The surface of the outer cover (especially the outer cover of the car) is not allowed to have defects such as ripples, wrinkles, dents, scratches, scratches, indentations, etc. The ridge lines should be clear, straight, and the curved surface should be smooth and evenly transitioned. 3. Good rigidity. During the forming process, the material should be sufficiently plastically deformed to ensure that the part is sufficiently rigid. 4. Good processability. The cover should have good stamping process performance and welding process performance to reduce the production cost of stamping and welding. The stamping processability is mainly based on the various processes, especially whether the drawing process can be carried out smoothly and whether it can be stably produced. Six, the composition of the general mold Working part Includes parts such as punches and dies. 2. Positioning parts It mainly includes parts such as retaining pin, positioning pin and side edge. 3. Pressing, unloading, and topping parts It mainly includes parts such as discharge plate, ejector and pneumatic topping device. 4. Guide parts Including guide posts, guide sleeves, guides and other parts. 5. Support parts It includes upper and lower stencils and parts such as convex and concave mold fixing plates. 6. Fastening parts Includes parts such as socket head cap screws and discharge screws. 7. Buffer parts Including discharge springs, polyurethane rubber and nitrogen cylinders. 8. Safety parts and other auxiliary parts There are mainly safety side pins, safety screws, work limiters, storage limiters, loading and unloading racks, waste chutes, lifting bars, lifting lugs, etc. Safety side pin: The main function is to prevent the fastening screw of the upper die plate from loosening or breaking, which causes the pressure plate to fall, resulting in significant loss of personnel and tooling. Storage limiter: The main function is to prevent the long-term compression of the elastic element of the mold and prevent the long-term contact of the cutting edge from affecting the life of the cutting edge. (Generally used polyurethane rubber) Work limiter: The main function is to limit the depth of penetration of the male and female molds. Seven factors affecting the life of the mold 1. The influence of stamping process and die design and measures to improve die life. (1) Influence of raw materials for cold stamping For example: raw material thickness tolerance does not meet requirements, material performance fluctuations, surface quality is poor and not clean, etc. A. Strict inspection of the grade, thickness and surface quality of raw materials before stamping B. Ensure the surface quality and cleanness of the material (2) The influence of layout and edging The layout method and the edge value have a great influence on the life of the mold. Unnecessary reciprocating feeding method and too small edge value are often the important reasons for the sharp wear of the mold and the bruise of the convex and concave mold. (3) Influence of mold guiding structure and guiding precision Necessary and reliable guidance is extremely effective in reducing the wear of working parts and avoiding the damage of the convex and concave molds. (4) Influence of mold geometric parameters 2. The shape, clearance and fillet radius of the convex and concave mold not only have a great influence on the forming of the stamping part, but also have a great influence on the wear of the mold. (1) Influence of the material of the mold The influence of the material properties of the mold and the quality of the heat treatment on the life of the mold is the most important factor affecting the life of the mold. (2) Effect of hot working and surface strengthening of the mold (3) Influence of mold processing technology The surface roughness of the mold after the mold processing has a great influence on the life of the mold, so it is necessary to select the processing technology according to the condition of the workpiece. (4) Influence of precision and rigidity of the press (5) The influence of the use, maintenance and maintenance of the mold Proper use, maintenance and storage of molds is an important aspect of improving mold life. It includes correct installation and adjustment of the mold; pay attention to keep the mold clean and reasonable lubrication; prevent misfeeding, double material; strictly control the depth of the punch into the die, control the bottom dead center position of the upper die in the process of correcting bending and shaping ; timely grinding, polishing, etc. Eight, the main content of the process discipline inspection 1. Check whether the drawings, standards, product design change notices and other documents of the product are complete, whether they can meet the production needs, and whether they comply with the relevant regulations on process management. 2. Check whether the process documents are complete and can meet the production needs. The process documents used on the site of the stamping workshop mainly include work instructions, inspection instructions, and metal consumption quota. 3. Check that the technical documentation is correct, complete, and uniform. 4. Check whether the materials, work-in-progress and finished products meet the process requirements. 5. Check the status of process equipment and tooling technology. 6. Check the correctness and timeliness of the quality inspection. 7. Check production site management. 8. Check the process management work. 9. Check the status of the various types of personnel to perform the work instructions.