Die stamping parts always have burrs. The quality of the blanking section is ugly. It only needs these three steps

Punching is a stamping process that uses a punching die to separate sheet materials under the action of a press. In a broad sense, punching is a variety of separation processes such as punching, blanking, cutting, cutting, and cutting. The general term. But generally speaking, blanking mainly refers to blanking and punching processes. Punching is a basic process in the cold stamping process, and it has a wide range of applications. It can directly punch out the required finished parts or prepare blanks for other cold stamping processes. After the sheet is punched, it is separated into two parts, namely the punched part and the holed part. If the purpose of punching is to obtain a certain shape of the contour and the size of the punched part; this punching process is called For the blanking process, the remaining part with holes becomes waste. On the contrary, if the purpose of punching is to obtain an inner hole of a certain shape and size. At this time, the punched part becomes waste, with holes, and the part is the workpiece , This punching process is called punching process. See the table below. Classification of punching Die stamping parts are divided into ordinary punching and precision punching according to the roughness of the cut surface or the accuracy of the punching parts. Ordinary blanking is when the workpiece is separated, due to the pressure of the die. In addition to the shear deformation of the material between the convex and concave edges, there are also deformations such as stretching, bending, and transverse extrusion. The material is finally torn The form is separated. Therefore, the section of the ordinary blanking workpiece is relatively rough, and has a certain taper, and its accuracy is low. Due to the special punching structure of the precision blanking, the material at the edge of the convex and concave die is finally plastic The shearing deformation forms are separated. The section of precision blanking parts is smooth and perpendicular to the board surface, and the accuracy is high. At present, some blanking parts with high precision requirements, such as instruments, cameras, clocks and other parts are mostly used It is processed by the precision blanking method. If the blanking is according to the use requirements of the separated part and the base material part, it can be divided into punching, blanking, cutting, cutting, semi-cutting, etc. The characteristics of deformation can be known from the analysis of the principle of plastic deformation of metals. The main ways that plastic metal materials cause damage to metal materials during the deformation process are tensile and shear, which means tensile stress and tensile strain. The factors that cause metal material fracture are probably shear stress and Shear strain. Compressive stress and compressive strain can only cause deformation of plastic materials, and will not cause material damage. Although the blanking separation process is completed in an instant, the deformation separation is very complicated. The stamping separation deformation is mainly divided into the following three stages: 1. Under the pressure of the punch in the elastic deformation stage, the material at the cutting edge is first Deformation such as elastic compression, stretching, etc. occurs. The punch is slightly squeezed into the inside of the material, and the bottom of the sheet is slightly squeezed into the cavity of the concave mold. The material under the punch is slightly bent. The material on the top of the concave mold starts to warp. If the blade gap between the male and female molds is larger, the warpage and warpage will be more serious, but at this time, the internal stress of the material has not reached the limit state. When the external force is removed, the material can still return to its original shape. This stage is called elastic deformation Stage (Figure 2.1-1) 2. As the punch drops, the pressure on the sheet metal continues to increase, and the internal stress of the material also increases. When the internal stress reaches the yield limit of the material, it starts Entering the plastic deformation stage, when the male and female molds further rush into the inside of the material. Due to the existence of the gap between the edges of the male and female molds, the tensile stress and bending inside the material become larger, the compressive stress component is reduced, and the material is further bent and stretched. The material in the deformation zone is hardened intensified. When the punching force continues to increase until the material near the cutting edge begins to produce microcracks, the punching force also reaches the maximum value. The appearance of microcracks (cracks) indicates that the material has begun to be damaged and plastic The deformation stage is also over. 3. The separation stage. The punch continues to descend, causing the sheet to produce upper and lower cracks and expand continuously. And extend to the inside of the material, as shown in Figure 2.1-3. When the upper and lower cracks of the sheet overlap, the material fibers are All the parts are torn and broken, and the section of the part starts to separate. When the punch is lowered again, the punched part of the sheet is pushed out of the cavity of the die, and the initially formed burr is further elongated, as shown in Figure 2.1-4. At this point, the convex The die rises to complete the entire blanking process.