(1), to overcome the springback of bending materials to bending parts.

The main materials used in bending stamping are alloy steel, cast iron, carbon steel and cemented carbide. When bending stamping, if the elastic deformation of sheet metal is large, it is easy to rebound after bending. Before stamping, the sheet metal can be heat treated to change the stress structure inside the sheet metal and properly solve the springback problem during bending.

(2) Overcome the springback of bending parts from the die structure.

① For materials with large resilience, such as medium carbon steel, manganese steel and hard brass. When the bending radius is large, the rebound angle can be compensated on the convex-concave die or the ejector of the concave die can be made into an arc to compensate the rebound of the fillet. (2) When the rebound angle of general materials is less than 5 and the deviation of workpiece thickness is small, the punch or die can be made into a negative angle, and its bending gap can be made into the minimum material thickness to overcome the rebound after bending.

(3) correction method: when the material thickness is greater than 0.8 mm, when the plasticity is good and the bending radius is small, the pendulum structure can be adopted to concentrate the correction force in the bending deformation area to reduce the rebound.

(4) Longitudinal pressurization method: after the bending process is completed, the end of the bending part is longitudinally pressurized by the shoulder of the die, so that the section of the bending deformation zone is subjected to compressive stress, and the rebound trend inside and outside the workpiece is opposite when unloading, which greatly reduces the rebound. There are commonly W-shaped bending, V-shaped folding and U-shaped folding reverse molding.

(3) Polyurethane rubber bending die can be used for thinner bending parts. The stamping depth of polyurethane rubber die consists of two parts: the depth of die attachment and the depth of shape correction. The depth of die attachment refers to the depth at which the punch enters the rubber pad when the sheet is attached to the punch.