What are the precautions when designing and processing the discharge plate of the stamping die

There are two types of discharge plates in the stamping die. One is a rigid discharge plate, which has a large discharge force and reliable discharge. It is mainly used for stamping strips with a thickness of 0.5mm or more. One is a spring-loaded unloading plate, which uses elastic elements such as rubber and springs to provide unloading force. It not only has a pressing effect on the blank before stamping, but also can discharge smoothly after stamping, so the stamping parts are relatively flat. It is mainly used in In the stamping process of thin materials. So what are the precautions when designing and processing the discharge plate of the stamping die? (1) The unloading plate should not ignore the processing of spring pockets. Due to the limitation of springs and other parts, the elastic unloading plate has a small unloading force and a limited life span, so sometimes the unloading is not reliable. In order to improve the life of the discharge spring and prevent the spring from eccentric force, the spring sockets should generally be designed and processed on the discharge plate (or fixed plate). (2) The size of the unloading plate should not be ignored. The spring arrangement is a common unloading form in the die. The unloading stamping parts through it are relatively flat, so it is widely used. The size of the discharge plate is generally the same as that of the punch fixing plate. Due to the limitation of springs and other parts, the discharge force of the elastic discharge plate is small, so it is sometimes not reliable when unloading. In order to increase the discharge force, a strong spring with a high stiffness coefficient should generally be selected, and preloading is required to increase it. The effective compression stroke uses multiple springs to provide sufficient discharge force. Therefore, the size of the discharge plate should also consider the arrangement of the springs, and the springs should be distributed as evenly as possible to balance the movement of the discharge plate. (3) The discharge plate of the small hole punching die should not be a punching die without guiding punching small holes (such as a punching die with multiple punches for the rotor sheet of a punching motor) or a continuous punching die with punching small holes, because the punches are small. , The compression strength is insufficient, and the punch is easy to break. For this reason, the punch is often equipped with a punch protection sleeve, and the upper and lower molds are guided by guide posts and guide sleeves. In addition, in order to prevent the unbalanced force of the unloading plate from causing the small punch to break, the unloading plate should also be guided by a small guide post, or a guide sleeve installed on the unloading plate to guide the movement of the punch to enhance the slenderness The stability of the punch during punching. (4) Continuous mold discharge plate should not be ignored. The continuous mold is a highly efficient mold. It is very important to maintain the stability of its work and reduce the number of maintenance during production. Therefore, no matter from design or manufacture of continuous mold, more details need to be considered. The unloading plate is a main part of the continuous die. Because it not only takes the role of pressing and unloading, but also guides the punch and continuously collides with the die and other parts. Therefore, it should also have sufficient strength and hardness. Have a better service life. For this reason, the material of the discharge plate of the continuous die is generally the same as that of the female die, and it needs to be quenched 55-58HRC. (5) The discharge plate of fine blanking die should not be unguided. With the development of fine blanking technology to large-scale and composite processes, the proportion of fixed convex pattern fine blanking dies is increasing. In the fixed-convex fine-blanking die, the punch is fixed on the die base and the unloading plate (which also serves as the blank holder) keeps relative movement through the force-transmitting rod, the die base and the punch, and the unloading plate is at the same time. The guide post of the die set slides on the guide post, the movement is stable, and the pressure is balanced, which is effective in ensuring the quality of the fine-blanking parts and prolonging the service life of the die. (6) The unloading board cannot have the function of tilting the unloading board to take and unload the strips in the die during the unloading process. The unloading force is generally provided by elastic elements or hydraulic and pneumatic power devices. It is required that the unloading plate moves smoothly and cannot be tilted during the unloading process, otherwise it will cause unloading difficulties, accelerate the wear of the punch and damage the mold. In order to prevent unbalanced unloading force during the unloading process (which is easy to occur when unloading with springs and rubber elastic elements), guide elements are generally added to the unloading plate or a shaft sleeve is used to fix the position of the unloading plate. Since the length of four or more shafts can be ground to the same size, the lower plane of the discharge plate has good parallelism with the upper plane of the concave mold, the movement of the discharge plate is stable, and the force is better, which is beneficial to protect the convex mold. , Improve the life of the mold. (7) The thickness of the unloading plate should not be too small. During the stamping process, the unloading plate is not only affected by the unloading force and pressing force, but also subjected to the impact force from the die, so the unloading plate has a certain strength. And stiffness requirements. For example, the unloading force of ordinary stamping is about 5% to 8% of the punching force, and the blank holder force during fine blanking is about 40% of the fine punching force. Therefore, this force is still very large and it is easy to cause the unloading plate. The deformation affects the normal operation of the mold. That is, the thickness of the discharge plate should not be too small. Previous post: What problems should be paid attention to when steel pipe partial upsetting