| 摘要 |
PURPOSE:To provide the method and mold for forming the optical disk substrate capable of yielding the good optical substrate which is not affected by the distortion of its outer peripheral part, the shape of flatness and transferability without increasing a post stage, such as trimming. CONSTITUTION:The cavity surfaces 1a, 2a of the mold are formed to the bore larger than the final outside diameter r of the molded substrate 4 for the optical disk. An outer peripheral blanking punch 5 to determine the final outside diameter r is disposed within the mold for forming the molded substrate 4. This outer peripheral blanking punch 5 is so set that its end face is flush with the cavity surface 2a of the mold and thereafter, a raw material 9 for the molded article is packed into the cavity A. The outer peripheral blanking punch 5 is extruded by a punch driving means 6 to determine the outside diameter of the molded substrate 4 during the pressure holding stage after the completion of the packing. |
