| 摘要 |
PURPOSE:To prevent the developments of void, defective unloading and the like and, at the same time, obtain excellent mass production stability by a method wherein the speed of travel of a plunger is controlled by a plurality of steps when the resin put in a mold pot is poured in a cavity by moving the plunger. CONSTITUTION:At molding, firstly a plunger 5 is lowered through a ball screw jack 4 in a pot 2 at high speed by rotating a servo motor 3 by means of a microcomputer unit 7 at first rotational frequency N1. Next, when the plunger displacement detected with a pulse generator 10 becomes equal to first displacement position, the rotational frequency of the servo motor 3 is changed-over to second rotational frequency N2 (<N1) so as to lower the plunger 5 at low speed. Under the condition as mentioned above, resin 11 under molten state is poured in the cavity 14 of a mold 1. When the plunger reaches the position just before the completion of the filling of the resin or second displacement position, the rotational frequency of the servo motor 3 is kept at the second rotational frequency and the molding is brought to an end under the condition that is the predetermined pressure is loaded onto the resin even after the completion of filling. |
