| 摘要 |
PURPOSE:To mold a disc board whose flatness is high by controlling generation of a warp, by a method wherein an ejection operation of a knockout pin is started in conformity with starting of mold break and a moving speed of the knockout pin is established at specific one. CONSTITUTION:Simultaneously with starting of mold break of a bottom force 2 a molded product 9 is released from the bottom force 2 with an ejection operation of a knockout pin 7. Since a moving speed of the knockout pin 7 is established at about a half of a mold break speed, spatial distances L1, L2 among the top A and bottom B of the molded product 9 and cavity plate surfaces (a), (b) of the top and bottom forces 1, 2 are held at the same ones in a raising course of the knockout pin 7. With this construction, temperature conditions of the top A and bottoms B of the molded product 9 become identical with each other, temperature differentials are hardly generated between the top A and bottom B, as a result of which a warp of the molded product 9 taken out of the mold becomes a little value. |
