| 摘要 |
PURPOSE:To prevent the deflection of synthetic resin pointers by large runner by disconnecting a large center runner through which synthetic resin is supplied into pointer-forming portions when a large number of synthetic resin points are concurrently and integrally manufactured. CONSTITUTION:A cavity is formed by a fixed mold 5 and a movable mold 6 and a synthetic resin is cast into the cavity from a gate 11. The synthetic resin quickly goes into pointer-forming recessed portions 10 and 13 through a central cavity 9, a tunnel gate 12, and recessed portions 7 and 8 and molded. In the injection molding, when the movable mold 6 is separated from the fixed mold 5, a molding A is separated as it is in contact with the movable mold by an ejection pin 16, whereupon, however, the central runner 3 is disconnected at the tunnel gate 3b by means of the tunnel gate 12 of the fixed mold 5. By this, the warpage of pointers due to the large shrinkage of the large central runner can be avoided. |
