Injection compression molding method and injection compression molding machine

#1. Field of the Invention

#The present invention relates to injection compression molding, particularly to gate sealing and prevention of occurrence of vertical burs at the time of gate cutting.

#2. Description of the Prior Art

#FIG. 1 is a schematic diagram of an embodiment of a compression molding machine of the present invention.

#FIG. 2 is an explanation of changing an electro-magnetic valve to control the male cutter in a compression machine shown in FIG. 1.

#FIG. 3 is a function explanation of a conventional male cutter in a conventional compression machine.

#First, on the basis of FIG. 1, an embodiment of a compression machine of the present invention is explained. The compression machine of this embodiment comprises a stationary mold 1 fixed on a stationary base (not shown), a movable mold 2 fixed on a movable base (not shown) which is movable free to and fro against the stationary mold 1, a female cutter 5 mounted on the stationary mold 1, a male cutter 6 mounted on the movable mold 2 movably to and fro to carry out gate-sealing and gate-cutting at the central opening of the moldings by being advanced, a driving means 7 for driving the male cutter 6 to and fro and an advancing speed changing means 8 to make the advancing speed change. When both molds 1 and 2 come close and abut, a cavity 3 is formed between them.

#The female cutter 5 comprises a sprue bush 11 inside the cutter concentrically which is located approximately at the center of the stationary mold 1. Opposite to the cavity 3 to which the sprue opens, on the other end of the bush 11, a nozzle (not shown) for filling the material is connected.

#Approximately at the center of the movable mold 2, the male cutter 6 is disposed in order to coincide with the female cutter 5. At the proximal end (at left side of FIG. 1) of the male cutter 6, a piston 14 is provided, which is moved to and fro in a cylinder 15 provided in the movable mold 2.