PURPOSE: To reduce manhour and manufacturing cost by working a punched and perforated metallic sheet so that the residual pattern part is pushed out to make a cylindrical part or part of it and the zigzag of the zigzag shape part is elongated.
CONSTITUTION: Prescribed holes are made on the metallic sheet 10 to form zigzag shape parts 12 where polygonal lines are lengthened and zigzagged from a site A making the bottom of a bottomed cylindrical part to the outward radial direction as they approach the outside. Through holes 14 enclosed by the zigzag shape part 12 are larger as they approach the outside and nearly rhombic. These zigzag parts 12 make the cylindrical parts of a bottomed cylindrical component. When the metallic sheet 10 perforated is drawn by a punch and a die, the area A of the metallic sheet 10 is pushed down by the punch, its peripheral side part is bent in a cylindrical shape, the zigzag of the zigzag shape part 12 is elongated in the shape of a straight line and projects in the cylindrical shape. In this way, a desired shape can be formed by a single working.