Solution

(1) Overcoming the springback of bending parts from bending materials

The materials used in bending stamping mainly include alloy steel, cast iron, and carbon steel , cemented carbide, etc. When bending and stamping, if the elastic deformation of the sheet is large, rebound will easily occur after bending. The sheet can be heat treated before stamping to change the stress structure inside the sheet. Properly address springback during bending.

(2) Overcome the springback of bent parts from the mold structure

① For materials with large springback, such as medium carbon steel, manganese steel, hard brass, etc., when When the bending radius is large, a compensation rebound angle can be made on the convex and concave molds or the ejection part of the concave mold can be made into an arc to compensate for the springback of the rounded part. ② When the springback angle of general materials is <5°, and the thickness deviation of the workpiece is small, the punch or die can be made into a negative angle, and the bending gap can be made into the minimum material thickness to overcome the springback after bending. .

③Calibration method, when the material thickness is>0.8mm. When the plasticity is good and the bending radius is not large, a pendulum block structure can be used to concentrate the correction force on the bending deformation area and reduce springback.

④Longitudinal pressure method. After the bending process is completed, use the shoulder of the mold to longitudinally pressurize the end of the bent part, so that the cross section of the bending deformation zone is subject to compressive stress. When unloading, the workpiece The rebound trend on the outside is opposite, which greatly reduces the rebound. Common ones include W-shaped bends and reversely shaped V-shaped bends and U-shaped bends.

(3) For thinner bending parts, polyurethane rubber bending molds can be used. The stamping depth of the polyurethane rubber mold consists of two parts: the mold sticking depth and the correction depth. The mold attaching depth refers to the depth of the punch entering the rubber pad when the sheet material and the punch are attached.