What is the reason why precision stamping and bending parts are always off-track, and how to solve the 'hardware'

In the process of stamping and bending, when the steel plate enters the lower mold, the mold has a frictional force on the steel plate, which will cause the steel plate to enter the mold at different speeds at different positions. After the stamping is completed, the bending position of the precision stamping and bending parts will deviate when the product is taken out. This will cause a larger error in the size of the entire product, and may also cause the product to be scrapped. 1. Reasons for the deviation of precision stamping and bending parts ①When asymmetric stamping parts are bent, the contact area between the two sides of the steel plate and the mold is not the same, which causes the friction on both sides of the steel plate to be unequal, and the steel plate will be wider after stamping. The side is running off the track. ②The number of bends on both sides of the stamping and bending parts is different. The side with more bends has higher friction resistance, and the steel plate deviates in the direction of the more bends. ③In the bending of V-shaped stamping parts, if the mold is not symmetrical, the edge of the die with a smaller angle is closer to the top of the punch, and the positive pressure acting on the edge of the die is greater, so the friction is also greater. The steel plate deviates to the side with the smaller angle of the die. ④The fillet radii on both sides of the mold are not equal, the friction with a small fillet radius is large, and the friction with a large fillet radius is small, causing the steel plate to deviate in the direction of the small fillet radius. ⑤When the gap between the two sides of the mold and the lubrication are inconsistent, the steel plate runs in the direction of small gap and poor lubrication. 2. Measures to prevent deviation of precision stamping and bending parts ①Use symmetrical die as much as possible for the bending die. The radius of the round corners on both sides of the die slide is equal, and the gap between the punch and the die is even. Avoid unequal left and right angles of the die during V-shaped bending. ②Adopt the bending die with back pressure elastic top device. When bending, the steel plate is pressed by the spring top device and the punch first, and then the steel plate is gradually lowered and bent into shape. The steel plate is pressed tightly during bending, reducing or solving slippage. ③Using a bending die equipped with a positioning pin, which uses the hole at the bottom of the bending piece and sets it in the positioning pin on the back pressure top plate, so that the steel plate cannot move during bending, thereby preventing slippage.