| 摘要 |
PROBLEM TO BE SOLVED: To solve the following problem: burrs higher than the central area surface of a disk substrate are formed in the interior hole end part of the disk substrate during the molding of the disk substrate, crushed in the following process, dropped on the transfer surface of the disk substrate to cause the occurrence of a defective, and contacted with each other when laminated on another disk substrate to obstruct the lamination. SOLUTION: In a mold 11 for molding the disk substrate having a fixed mold 12 and a movable mold 13 forming a cavity 14 when put together, a male cutter 28 which is set in the movable mold 13 and can be projected, a female cutter 19 set in the fixed mold 12 and provided with an interior hole 19a into which the male cutter 28 is inserted, and a sprue bush 20 which is set in the interior hole 19a of the female cutter 19 or formed integrally and to which a molten resin is supplied, an annular projection part 30 of the height of 30-80μm is formed in the tip surface of the female cutter 19 to adjoin the interior hole 19a. COPYRIGHT: (C)2006,JPO&NCIPI |
