| 摘要 |
PURPOSE:To obtain a mold assembly capable of forming a resin discoid plate poor in residual strain and suitable for an optical disk by giving a very thin clearance around a mold cavity and deforming the very thin clearance so that it becomes smaller by the mold clamping pressure within the elastic limit of mold material. CONSTITUTION:Discoid cavities 4 are formed along the divided surfaces 3 on the movable mold 1 and on the fixed mold 2 and a very thin clearance 9 in a disk form is formed along the divided surface 3 on the whole outer circumferences of this discoid cavity 4. These molds are made deformable so that the discoid very thin clearance 9 is made smaller within the elastic limit. Resin pressure sensors 14, 15 are provided on the cavity surface. In the mold clamping stage the mold clamping pressure is made so low that resin does not leak from between the divided surfaces. When the resin pressure in the cavity has taken a specified value, the resin injecting pressure is reduced, the resin is cooled, hardened and mold clamping pressure is reduced, the resin is cooled, hardened and the mold clamping force is enlarged to give uniform push force to the resin in the cavity. |
