Waste pre-cutting device for sheet metal stamping die

The invention discloses a waste pre-cutting device for a sheet metal stamping die. The sheet metal stamping die comprises an upper die, a lower die, a guide pillar, a guide sleeve and a feeding device, more than two working positions are arranged on the sheet metal stamping die in the feeding direction, and a waste pre-cutting device is designed before the normal process of product processing andcomprises a PLC sensor head, a punch, a limiting plate, a fixed screw, an inclined sliding block, a cylinder and a PLC control system. According to the waste pre-cutting device, the PLC control systemjudges whether waste exists by sensing the position and shape of a material belt through the PLC sensor head and then controls the action of the cylinder accordingly, the cylinder acts so as to drivethe inclined sliding block to drive the punch to act to cut off the waste, and the problems of die crushing, punch fracture and knife edge fracture caused by irregular waste remaining in a die due toan irregular material belt