A large number of cold stamping processes are used in the production of automobile stamping parts, which is suitable for the needs of multi variety and mass production of automobile stamping parts industry. In medium and heavy-duty vehicles, most of the covering parts such as the body outer panel, and some load-bearing and supporting parts such as frame and carriage are automobile stamping parts. The steel used for cold stamping is mainly steel plate and strip, accounting for 72.6% of the total vehicle steel consumption. Cold stamping materials are closely related to the production of automobile stamping parts. The quality of materials not only determines the performance of products, but also directly affects the process design of automobile stamping parts, and affects the quality, cost, service life and production organization of products. Therefore, reasonable selection of materials is an important task An important and complex task.
(1) Stamping in the automotive industry. Drawing is the main method. In our country, this part is mainly concentrated in automobile factories, tractor factories, aircraft manufacturers and other large factories.
(2) Automobile and other industries parts stamping. It is mainly formed by punching and shearing. Many of the enterprises in this sector are owned by standard parts factories, and there are also some independent stamping plants. At present, there are many small factories near some automobile factories or tractor factories.
(3) Electrical parts stamping plant. This kind of factory is a new industry, which develops with the development of electrical appliances. The factories in this sector are mainly concentrated in the south.
(4) Daily necessities stamping factory. Some handicrafts, tableware and so on, these factories also have the big development in recent years.
(5) Home appliance parts stamping plant. These factories were established after the development of household appliances in China, and most of them are distributed in household appliance enterprises.
(6) Special stamping enterprises. For example, the stamping of aviation parts belongs to this kind of enterprise, but these process factories are also included in some large factories.
Common problem handling of stamping parts:
1. Adhesion and scratch: defects on the surface of parts or dies due to friction between materials and punch or die;
2. Burr: it mainly occurs in the cutting die and blanking die. Burr will be produced when the gap between the cutting edges is large or small;
3. Line offset: during the forming of the part, the first part in contact with the die is extruded to form a line;
4. Convex concave: foreign matters (iron filings, rubber, dust) mixed into the uncoiling line to cause convex concave;
5. Twists and turns: due to uneven stress, poor matching of drawbead or poor control of slide block of the press, the R corner or embossed part of the part has twists and turns and strains;
6. Wrinkle: the edge or r part wrinkle is caused by poor adjustment of slide block, low precision of press, improper adjustment of air cushion pressure, large punch or R position, etc.
7. Other specific problems: in daily production, the punching size is too large or too small (may exceed the specification requirements) and has a large difference with the punch size. In addition to considering the design size of forming punch and die, machining accuracy and blanking clearance and other factors, the following aspects should be considered to solve.
(1) when the cutting edge is worn, the tensile stress of the material increases, and the stamping parts tend to turn over and twist. When turning over, the punching size will be smaller.
(2) strong pressure on the material will cause plastic deformation of the material, which will lead to larger punching size. When the pressure is reduced, the punch size will be smaller.
(3) shape of punch edge end. If the end is trimmed with inclined plane or arc, the punching part is not easy to turn over and twist due to the slow down of blanking force, so the punching size will be larger. When the punch end is flat (no inclined plane or arc), the punching size will be smaller.
8. Methods to prevent the stamping parts from turning over and twisting
Auto parts supplier
(1) reasonable mold design. In progressive die, the arrangement of blanking sequence may affect the forming accuracy of stamping parts. In order to reduce the influence of blanking force on the forming of stamping parts, the blanking with larger area is usually arranged first, and then the blanking of small area is arranged.
(2) press the material. It overcomes the traditional mold design structure, and opens the material holding gap on the discharge plate (that is, when the mold is closed, the material can be compressed. For the key forming parts, the discharge plate must be made into an inlaid structure, so as to solve the grinding (pressing) loss caused by the pressing part of the discharge plate caused by long-time stamping, and the material can not be compressed.
(3) add the function of strong pressure. That is to thicken the pressing part of the unloading insert (the normal thickness of the unloading insert is H + 0.03mm) to increase the pressure on the side material of the die, so as to inhibit the turning over and distortion of the stamping part during blanking.
(4) bevel or arc shall be made at the end of punch edge. This is an effective way to reduce the blanking force. The bending force of the drawing die can be reduced, and the bending force of the stamping die can be reduced.
(5) pay attention to the sharpness of punch die in daily production. When the cutting edge is worn, the tensile stress of the material will increase, and the stamping parts tend to turn over and twist.
(6) unreasonable blanking clearance or uneven clearance is also the cause of stamping parts turnover and distortion, which needs to be overcome.