Punching is a process in which one part of a sheet is separated from another part along a certain contour shape by using a punch. After punching, the sheet is divided into a perforated part and a punched part. If the purpose of punching is to obtain a hole of a certain shape and size, the punching is called punching. If the purpose of punching is to obtain a part with a certain profile and size, the punching is called dropout. Drop and punch the nature of the same, but the purpose of punching is different, to determine the size of the working part of the mold, should be considered separately.
Stamping production, the plastic deformation process of metal materials is carried out at room temperature, with the increase in the degree of deformation, its strength indicators such as yield point and tensile strength and hardness is increased, at the same time, its plasticity indicators of elongation, section shrinkage and impact toughness and so on the decline in the metal of the phenomenon is the hardening of the process. Components of metal materials, metallurgical organization and deformation conditions deformation temperature, strain rate and the degree of deformation has a great influence on the hardening. Due to work hardening, plastic forming process of metal material deformation resistance is increasing, deformation resistance is the metal of its own plastic deformation resistance to external forces, that is, the metal at each moment of the yield point of starvation is different. In determining the various stamping process parameters, analyze the deformation of the part of the stress-strain, must take into account due to hardening and deformation resistance caused by the change.
Processing hardening of many stamping and forming process has a greater negative impact, such as processing hardening so that the deformation force increases, limiting the further deformation of the blank and reduce the limit of the degree of deformation and sometimes in order to eliminate the hardening of the previous process in order to improve the molding limit of the process, and even increase the annealing process to eliminate hardening and hardening of the edge of the hole part of the hardening of the material is easy to cause cracking in the flange deformation. However, hardening is sometimes favorable to the deformation, such as elongation deformation, deformation zone hardening can make the deformation tend to uniform, increase the limit of deformation.
Therefore, in dealing with the actual problem of stamping production, to determine a variety of process parameters, analyze the deformation zone of the blank of the force situation, it is necessary to study and master the hardening of the material law and the impact of their stamping and forming process. Plate stamping and forming, blanks in different places of the stress state and strain state is different, only the stress state to meet the plastic conditions of the region will produce plastic deformation, other areas will not produce plastic deformation. Therefore, the blank can be divided into deformation zone and non-deformation zone. The deformation area is the area in the blank that reaches the plastic condition, and the non-deformation area is the area in the blank that does not reach the plastic condition. According to the non-deformation conditions of the force and deformation, and can be further divided into has experienced plastic conditions have been deformed area, to be involved in the deformation to be deformed area and all the stamping process are not involved in the deformation of the deformation of the undeformed area, when the non-deformed area to withstand the action of the force, that is, the force transfer area.
