| 摘要 |
PURPOSE:To perform high precision threading process by furnishing a lower die having a recess to accept insertion of a ring-shaped workpiece of resin, an upper die having a protrusion to form a ring-shaped cavity, and an arbor mold installed upright in the center of the recess. CONSTITUTION:A mold 20 is composed of a lower die 2 and an upper die 23. A ring-shaped recess 24 to accept insertion of a ring-shaped workpiece of resin is provided at the oversurface of the lower die 22. A ring-shaped cavity 21 is formed between a protrusion 29 and the inner surface of this recess 24. The inner surface of the workpiece B is provided with thread 28 with the molding pressure when vulcanization molding is performed, by means of injection of fluidified crude rubber into a ring-shaped cavity 21. Thus high precision threading is accomplished. |
