Injection molding machine

Abstract

An injection molding machine capable of accurately detecting a rotational force exerted on a screw by resin backflow to easily evaluate states of resin backflow and closure of a check valve. In a state where the screw is stopped axially and rotationally after metering is finished, a load exerted on the screw in the rotational direction is detected. This load is a rotational force exerted on the screw from resin remaining between flights of the screw (resistance torque component). During injection, a load T exerted on the screw in the direction of rotation is detected, and the resistance torque component is subtracted from the detected load T to obtain a backflow torque component generated by resin flowing back through the check valve. By simultaneously displaying waveforms of backflow torque components in a plurality of molding cycles to be overlapped, stability of closure of the check valve is readily evaluated.

Dependencies are inferred from the claim text.