Metal stamping: is a metal cold processing methods, also known as cold stamping or sheet metal stamping, with the power of stamping equipment, metal sheet in the mold directly under the force forming, stamping parts are widely used in auto parts manufacturing And the manufacture of household appliances.
Cost of process: mold cost (high), single cost (low – medium).
Production is suitable: only suitable for large quantities.
Quality: high precision of forming surface.
Speed: One piece is fast (1s-1min).
1. Suitable for most metal sheet, especially for: carbon steel plate, stainless steel plate, aluminum plate, magnesium plate, copper plate and zinc plate.
1. Stamping metal plate thickness is recommended to control between 0.4mm-2mm (0.02in-0.08in), too thick metal sheet will affect the molding effect.
2. Metal stamping restrictions are generally from the machine: machine table size determines the plate size, stamping depth and shape complexity determines the molding speed.
1. Fix the sheet metal on the die table.
2. The top punch vertical drop, so that the metal sheet within the mold force forming.
3. Punch up, parts are removed to wait for the next step trim grinding process, the whole process in about 1s-1min.
Stamping processing methods and other processing methods, are based on their own performance as a basis for processing, material stamping process must have a good stamping performance.
1. Material stamping performance
The ability of the material to adapt to various stamping processes is called the stamping properties of the material. Material stamping performance is good, that is, it is easy to stamping processing, a stamping process of the ultimate degree of deformation and the total degree of deformation of a large degree of high productivity, easy to get high-quality stamping parts, die long life. It can be seen, stamping forming performance is a comprehensive concept, it involves a lot of factors, but its main content, there are two aspects: First, forming the limit, the second is the forming quality.
(1) forming limit In the stamping process, the material can reach the maximum degree of deformation called the forming limit. For different forming processes, the forming limits are represented by different limiting deformation coefficients. Since most of the stamping is carried out in the plane stress state where the stress value in the thickness direction is approximately zero, it is not difficult to analyze: In the interior of the deformed blank, where the area is subjected to excessive tensile stress, Will make the blank part of the local severe thinning, and even rupture leaving the red scrap; any subject by the role of large compressive stress, if more than the critical stress will make the blank loss and stability and wrinkle. Therefore, from the material point of view, in order to improve the forming limit, we must improve the plasticity of materials and enhance the tensile strength, compression capacity. The
When the absolute value of the tensile stress applied to the blank deformation zone is maximum, the deformation in this direction must be elongated and deformed, so that the stamping deformation is such as elongation deformation (such as bulging, flaring, Hole flanging, etc.). When the absolute value of the compressive stress applied to the blank deformation zone is the largest, the deformation in this direction must be a compression deformation, so that the stamping deformation is such that the compression deformation (such as drawing, necking, etc.). The ultimate deformation coefficient of the elongated deformation is mainly determined by the plasticity of the material. The ultimate deformation coefficient of the compression deformation is usually limited by the carrying capacity of the blank transmission zone, and sometimes by the deformation zone or the transmission zone limit.
(2) the quality of forming stamping parts of the quality indicators are mainly dimensional accuracy, thickness changes, surface quality and after forming the physical and mechanical properties of materials. There are many factors that affect the quality of the workpiece, and the different stamping processes are different.
The material is accompanied by elastic deformation at the same time as the plastic deformation. When the load is removed, the size and shape of the workpiece are deviated from the mold due to the elastic recovery of the material, which affects the size and shape accuracy of the part. Therefore, to grasp the law of springback, control the amount of rebound is very important.
After forming the stamping, the general thickness should be changed, some thicker, some thinner. ? Thickness of the thinning directly affect the strength and use of stamping parts, the strength requirements, often to limit the maximum amount of thinning.
After the plastic deformation of the material, in addition to the phenomenon of work hardening, but also due to uneven deformation, resulting in residual stress, resulting in changes in the size and shape of the workpiece, serious also cause self-cracking of the workpiece. All of these conditions should be taken into account in the development of stamping processes.
The main factors that affect the surface quality of the workpiece are the surface state of the raw material, the grain size, the condition of the material sticking at the time of stamping, and the abrasion of the surface of the stamping part. The surface condition of the raw material directly affects the surface quality of the workpiece; • The thick steel sheet is stretched to produce the so-called ‘orange peel’ defects (rough surface); • Stamping materials that are easy to stick mold will scratch the stamping parts and lower the mold life. In addition, the mold gap is uneven, the mold surface rough will scratch the stamping parts.