| 摘要 |
PURPOSE:To bond a hub to an optical disk substrate in an injection molding process by vertically attaching the magnetic disc of a hub to the vertical surface of the leading end of the ejection piston provided to the center of a mirror surface and providing a cylindrical center gate part to which a hub substrate is formed. CONSTITUTION:A hub substrate constituting a hub 4 is molded in the center gate part 16 between the surface on the side of a movable mold 28 of the sprue bush 40 of a fixed mold 27 and the surface on the side of the fixed mold of the ejection piston 38 of a movable mold 28 and, at the same time, an optical disk substrate is molded in the cavity part 18 communicating with the center gate part 16. Further, the magnetic disc 6 vertically preset to the center of the mirror surface 33 of the movable mold 28 is bonded. By this constitution, an optical disk fitted with a hub can be integrally molded. |
