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 the rigid discharge plate, which has large discharge force and reliable discharge, and is mainly used for strips with a thickness of more than 0.5mm. One is the elastic pressure discharge plate, which uses rubber, spring and other elastic elements to provide the discharge force. It not only has a pressing effect on the blank before stamping, but also can discharge smoothly after stamping. Therefore, the stamping part is 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 processing of the spring socket should not be ignored on the discharge plate
Due to the limitation of springs and other parts, the elastic pressure discharge plate has a small discharge force and a limited life, so sometimes the discharge is not reliable. In order to improve the life of the discharge spring and prevent the spring from being subjected to eccentric force, the spring socket should be designed and processed on the discharge plate (or fixed plate).

(2) The size of the discharge plate should not ignore the arrangement of the spring
Elastic pressure discharge plate is a common discharge form in the die. The stamping parts discharged by it are relatively flat, so it is widely used. The size of the discharge plate is generally consistent with the external dimensions of the punch fixed 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 discharging. In order to improve the discharge force, a strong spring with a high stiffness coefficient should generally be used, and preloading is required to increase The effective compression stroke uses multiple springs to provide sufficient discharge force, so the size of the discharge plate also needs to consider the arrangement of the springs, as far as possible, the springs are evenly distributed so that the discharge plate moves balanced.

(3) The discharge plate of the punching die for punching small holes should not be unguided
The punching die for punching small holes (such as the punching die for punching rotor blades of a punching motor rotor) or the continuous punching die with small holes, because the punch is small and the compressive strength is insufficient, the punch is easy to break. The mold is often provided with a protective cover of the convex mold, and the upper and lower molds of the mold are guided by a guide column guide sleeve. In addition, in order to prevent the unbalanced force of the discharge plate and cause the small punch to break, the discharge plate should also be guided by a small guide post, or the guide sleeve installed on the discharge plate can guide the movement of the punch to enhance the slenderness. Stability of punch during stamping.

(4) continuous mold discharge plate should not ignore heat treatment
The continuous mold is a high-efficiency mold. It is very important to maintain the stability of its work and reduce the number of repairs in production. Therefore, whether the continuous mode is designed or manufactured, more details need to be considered. The discharge plate is a main part in the continuous mold. Because it not only takes the pressure to discharge the material, but also guides the punch and continuously strikes the concave mold and other parts, 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 mold is generally the same as the material of the concave mold, which requires quenching 55-58HRC.

(5) The discharge plate of the fine die should not be unguided
With the development of fine blanking technology to large-scale and compound processes, the proportion of fixed convex mode fine blanking dies is increasing. In the fixed punch mode fine blanking die, the punch is fixed on the die base, and the discharge plate (which also functions as a blank holder) maintains relative movement through the force transmission rod, the die base, and the punch. Sliding on the guide post of the die frame, the movement is smooth and the pressure is balanced, which is powerful to ensure the quality of the fine blanking parts and prolong the service life of the die.

(6) the discharge plate must not be inclined during the discharge process
The role of the unloading plate in the die is to take off and discharge the bar material. The discharge force is generally provided by elastic elements or hydraulic and pneumatic power devices. It is required that the discharge plate moves smoothly during the discharge process without tilting, otherwise it will cause difficulty in discharging and accelerate the wear of the punch and damage the mold. In order to prevent the unloading force from being unbalanced during discharge (it is easy to appear when unloading using springs and rubber elastic elements), generally guide elements are added to the unloading plate or a sleeve is used to fix the position of the unloading plate. Because the length of four or more shafts can be ground to a uniform size, the lower plane of the discharge plate is parallel to the upper surface of the die, the discharge plate moves smoothly, and the force is better, which is beneficial to protect the punch To increase the life of the mold.

(7) The thickness of the discharge plate should not be too small
During the stamping process, the discharge plate has not only the effects of discharge force and pressing force, but also the impact force from the die. The discharge plate has certain strength and rigidity requirements. For example, the discharge force of ordinary punching is about 5%~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, it is easy to cause the discharge plate The deformation will affect the normal operation of the mold. That is, the thickness of the discharge plate should not be too small.

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