| 摘要 |
PURPOSE:To enhance the efficiency of production by carrying out the cutting-off, thread cutting, and bending processes of a seal ring by one process. CONSTITUTION:While a resin raw material 10 and a tool 11 are relatively turned, a cutting-off part 12 is moved outward in the radial direction toward the outside diameter side from the inside diameter side of the resin raw material 10. When a thread cutting part 13 moves to the position of the inside diameter of the resin raw material 10, on the cutting surface 14a of a cut-off chip 14 of the resin raw material 10 a screw groove 3 is spirally cut from the end of its inside diameter. When the tool 11 moves further outward in the radial direction, the inside diameter end part of the cut-off chip 14 on which the screw groove 3 is cut is expanded in diameter along the guide part 15 to be bent in a cylindrical shape. |
