| 摘要 |
PURPOSE:To produce a small plug product by drawing integrated with plateworking by drawing the central part of a blank to form a square plug body then drawing a clindrical plug body around the plug body and further forming a flange at the circumferential edge of a top plate and thereafter subjecting the outside circumferential part of the plug body to thread cutting. CONSTITUTION:The central part of a blank 10a is deeply recessed with gradul deformation to form a recess 12d having a final shape of a plane square shape. The outside of the recess 12d is drawn to form a cylindrical part 14a and the opening in the cylindrical part is trimmed and is further subjected to edge raising and edge ironing to raise the opening end 14b remaining after the trimming and to iron the end face at the same instant. A flange 13 is formed in the circumferential edge part formed with the recess 12d to be made into a plug body and as final working the opening in the cylindrical part is subjected to hemming, thereby forming a half-finished part 16 of a plug. Screw therads are further cut in the part 14a to finish the plug. The plug having improved strength is thus obtd. at a low cost. |
