Why do metal stamped parts twist and twist?

The shape of the stamped parts is formed in a progressive die by stamping the remaining material around the stamped parts. The main reason for rotation and twisting of stamped parts is the influence of stamping force. During stamping, due to the presence of a stamping gap, the material is stretched on one side of the die (the material warps upward) and compressed on the side of the punch. When using the relief plate, use the relief plate to compress the material to prevent the material on the die side from being deformed. At this time, the stress state of the material changes accordingly. As the pressure force of the relief plate increases, the material on the male side of the die is stretched (compressive force tends to decrease), and the material on the concave surface of the die is compressed (tensile force tends to decrease). Flipping of stamped parts is caused by stretching of the material on the surface of the die. Therefore, when stamping, pressing and compressing the material is the key to preventing the stamped parts from turning over and twisting. Reasons and countermeasures for turning and twisting of stamped parts during bending: 1. Caused by burrs of stamped parts formed during stamping. It is necessary to repair the perforation edge and check whether the perforation gap is sufficient. 2. During stamping, the perforated parts were turned over and twisted, resulting in poor forming after bending. This problem must be solved at the stamping and punching station. 3. Caused by instability of stamped parts when bending.