The main defects of the stamping process

The stamping process design can be divided into two types: the separation process and the forming process. The separated technological process includes blanking, punching, edge pressing, etc., and the forming process includes bending, stretching, flanging, etc. Each process has the defects of springback, wrinkling and cracking. Today, Precision will put forward more detailed preventive measures and solutions. 1. Springback Most stamping parts have the shortcomings of springback. The direct cause of springback can be summarized as follows, that is, after the parts are deformed by stamping, the material will cause partial or overall deformation due to the ductility. Stamping die materials, working pressure size and die conditions are all harmful to springback. In view of the shortcomings of springback, the processing ideas are as follows: (1) Compensation, that is, based on the size of the springback of the stamped part after bending and forming, the inclination equivalent to the springback of the product workpiece is made in advance on the mold to compensate the product workpiece The springback after forming, the size of the springback that often needs to be compensated in this way is determined based on the human work experience or the CAE finite element analysis results; (2) Bending processing method: release the tensile force in the bending of the sheet For this reason, the ground stress inside the sheet is more symmetrical, thereby reducing the amount of springback; (3) Partial compression method: the deformation zone becomes a three-way force ground stress condition, and the elastic deformation characteristics are changed from the source; (4) According to some reinforcing ribs and other ways to increase the bending rigidity, to increase the bending rigidity of the stamping parts and reduce the deformation. 2. Wrinkling The direct cause of wrinkling shortcomings is that the sheet material is subjected to extrusion molding. When the primary and secondary ground stresses in the plan view are at a certain level, the thin and thick azimuths are out of balance. According to the different reasons for wrinkles, they can be divided into two types. One is because of the material deposition and wrinkles caused by too much material entering the core of the cavity; the other is because of the imbalance of the thickness of the sheet or the uneven tensile stress. And the resulting imbalance wrinkles. In order to better deal with this shortcoming, the actual treatment concept is as follows: (1) From the perspective of designing products, consider: reduce the reverse side aspect ratio as much as possible; make the shape design change area silky smooth connection; the product can be easily wrinkled. Appropriately improve the design of the suction shape; (2) Consider from the design plan of the stamping die: expand the hemming force and manipulate the feed rate; the processing technology fills and enhances the ring or square drawing bead; enhances the forming process within the effective range (3) For the selection of stamping die materials: Under the condition of achieving product characteristics, for some parts that are easy to wrinkle, materials with good formability should be used. 3. Cracking The direct cause of the shortcomings of cracking depends on the strain force exceeding its bearing range during the whole process of stretching. The more visualized main manifestation is that the surface layer of the product causes cracks visible to the human eye. Generally, it can be divided into three categories: one is the cracking caused by insufficient tensile compressive strength of the material, and the cracking is generally caused by the convexity and the excessive force at the arc of the cavity; the second is due to the material Cracks due to insufficient deformation, such as cracks at the sharp point; three types of cracks are caused by residues in the material. Therefore, in order to better prevent the shortcomings of cracking, the more fundamental solution is to reduce the stress condition. The actual plan is as follows: (1) Select effective blank specifications and appearance; (2) Adjust the main parameters of deep drawing to avoid cracking due to excessive expansion; (3) Increase process wounds, clarify the allocation of material resources, and make the deformation uniform; (4) Change the lubrication standard to reduce sliding friction and expand the feed rate; (5) Reduce the edging force or select variable edging force to control the frictional resistance of the feed; (6) Use plasticity and forming Good material, reduce cracks. [Related recommendation] Learn more: What are the methods for polishing the surface of stainless steel? Learn more: Manufacturing characteristics of automotive stamping parts molds Learn more: Points to note in the design of continuous stamping dies