MANDREL WITH MARKING FUNCTION

PROBLEM TO BE SOLVED: To form impressions on a sheet metal part by projecting parts simultaneously with pressing, and to indicate places to be marked on the sheet metal part without an omission and special working by implanting the projecting parts on the work contact surface of the mandrel, which projects from the contact surface. SOLUTION: The surface of the mandrel 1 made of aluminum becomes the work contact surface 2 coming into contact with the single side of the sheet metal part to be formed, and is formed in the forming shape of the sheet metal part. And, the projecting parts 3 are provided on the work contact surface 2 corresponding to positions where the working parts of the sheet metal should be marked, such as places to be subjected to spot welding, positions of punching, etc. On the work contact surface 2, pins 4 for positioning are provided projecting as well. For the height of the projecting part 3 from the front surface of the work contact surface 2, a slight height is enough. The height is selected so that a rise, etc., caused by the projecting parts 3 are not generated on the rear surface of the sheet metal part at the time of press forming. In the case of an aluminum sheet 1.0mm thick, its proper value is about 0.5mm.