| 摘要 |
PURPOSE:To cut materials at low cost by fitting a cylindrical material having a groove provided in a circumferential direction into a cylindrical body having an annular rib in the inner circumferential surface and pressing the cylindrical material while being rotated. CONSTITUTION:The width of a groove 17 provided in a circumferential direction between a major diametral section 14 of mandrel and a sleeve 16 is set at a predetermined value, and the movement between the sleeve 16 and a minor diametral section 15 of mandrel is restricted by a sleeve attaching metal 16'. A cylindrical material is fitted on the major diametral section 14 of mandrel and the sleeve 16, and the end of the cylindrical material is caused to adhere to the mandrel-mounting side 14'. After this procedure, mandrels 14, 15 are caused to rotate to press a roller 11 to the cylindrical material and process it. The cylindrical material is elongated backward by the amount of a decrease in its thickness until the roller 11 reaches the groove in the circumferential direction 17 thus being formed into a thin cylindrical body. |
