METHOD AND APPARATUS FOR CHANGING MATERIAL AND COLOR IN INJECTION MOLDING MACHINE, AND APPARATUS FOR CHANGING MATERIAL AND COLOR IN ITS MOLD

摘要

PROBLEM TO BE SOLVED: To efficiently perform material change and color change in a short time.;SOLUTION: The apex 19A of a screw 19 is arranged more forward than a feeding opening 20A of a hopper 20 and is rotated, and a molten molding material in a heating cylinder 17 is discharged through a gate to a product cavity provided in a fixed mold 5 from a sprue. Opening and closing operation of a valve pin 66 is performed during material changing and color changing. By continuously passing a molding material under a molten condition through the sprue and the gate, an old molding material existing in the heating cylinder 17, the sprue, a runner and the gate is rapidly discharged. It is possible thereby to perform the material change and the color change in replacing the old molding material with a new molding material.;COPYRIGHT: (C)2003,JPO