An injection molding device includes a barrel, an injection screw, and an injection driving unit, wherein the injection screw includes a screw body, a screw head coupled to a front end of the screw body, and a check ring coupled to the screw head, the check ring including an accommodation groove that accommodates a portion of the screw head, a front member disposed in front of the screw head accommodated in the accommodation groove, and an accommodation member connected to the front member and surrounding a side surface of the at least a portion of the screw head accommodated in the accommodation groove, and when the injection screw moves forward to supply a molding material in the barrel to a clamping device, as the front member is pushed by the molding material accumulated on a front side of the injection screw, the check ring moves rearward from the screw head.

An injection molding device includes a barrel, an injection screw, and an injection driving unit, wherein the injection screw includes a screw body, a screw head coupled to a front end of the screw body, and a check ring coupled to the screw head, the check ring including an accommodation groove that accommodates a portion of the screw head, a front member disposed in front of the screw head accommodated in the accommodation groove, and an accommodation member connected to the front member and surrounding a side surface of the at least a portion of the screw head accommodated in the accommodation groove, and when the injection screw moves forward to supply a molding material in the barrel to a clamping device, as the front member is pushed by the molding material accumulated on a front side of the injection screw, the check ring moves rearward from the screw head.

An injection molding machine includes a screw inserted in an injection cylinder and configured to be movable in an axial direction of the screw, a motor configured to move the screw, a torque detection unit configured to detect a torque of the motor, a position detection unit configured to detect a position of the screw, a motor drive control unit configured to drive the motor to thereby advance the screw to a foremost position in a direction of injection, a processor, and a memory. The processor and memory are configured to determine that unmelted resin remains inside the injection cylinder if the torque of the motor becomes equal to or greater than a limit torque while the screw is advancing to the foremost position.

An injection molding machine includes a screw inserted in an injection cylinder and configured to be movable in an axial direction of the screw, a motor configured to move the screw, a torque detection unit configured to detect a torque of the motor, a position detection unit configured to detect a position of the screw, a motor drive control unit configured to drive the motor to thereby advance the screw to a foremost position in a direction of injection, a processor, and a memory. The processor and memory are configured to determine that unmelted resin remains inside the injection cylinder if the torque of the motor becomes equal to or greater than a limit torque while the screw is advancing to the foremost position.

A control device for an injection molding machine including a cylinder into which a resin is supplied, and a screw that moves forward and rearward and rotates inside the cylinder, includes a suck back control unit that sucks back the screw based on a predetermined suck back speed and a suck back distance or a suck back time period, a pressure acquisition unit that acquires a pressure of the resin, a calculation unit which calculates a compensation amount of the suck back speed, based on a difference between the pressure of the resin at a time when sucking back is completed and a predetermined target pressure, and a speed determination unit that newly determines the suck back speed based on the compensation amount.

A control device for an injection molding machine including a cylinder into which a resin is supplied, and a screw that moves forward and rearward and rotates inside the cylinder, includes a suck back control unit that sucks back the screw based on a predetermined suck back speed and a suck back distance or a suck back time period, a pressure acquisition unit that acquires a pressure of the resin, a calculation unit which calculates a compensation amount of the suck back speed, based on a difference between the pressure of the resin at a time when sucking back is completed and a predetermined target pressure, and a speed determination unit that newly determines the suck back speed based on the compensation amount.

An injection molding machine includes: a first driving device rotating a screw provided inside a heating cylinder; a second driving device moving the screw forward and backward; a metering control section configured to, by controlling the first driving device and the second driving device, to meter resin while melting the resin, and thereafter rotate the screw in reverse to thereby reduce the pressure of the resin; a first sensor unit for detecting the pressure; a second sensor unit for detecting one or more kinds of physical quantities that affect the change of the pressure; and a prediction section predicting decompressing rotation information based on the pressure detected by the first sensor unit and the one or more kinds of physical quantities detected by the second sensor unit. The metering control section controls the first driving device based on the decompressing rotation information predicted by the prediction section.

To reliably and safely suppress co-rotation of a screw drive unit when performing a tightening and loosening operation for a threaded fastener which fixes a screw to the screw drive unit. Provided is an injection molding machine 2 in which a threaded fastener 30 is tightened into a first threaded portion 23a of a screw drive unit 21, thereby fixing a screw 10 to the screw drive unit 21 through a fixation bush 25, wherein a jig 40, which is detachably mounted on the screw drive unit 21, and is brought into contact with a main body contact portion 4 of a main body portion 3 of the injection molding machine 2 by rotating the screw drive unit 21 to restrict further rotation of the screw drive unit 21, is mounted on the screw drive unit 21, and the threaded fastener 30 is tightened or loosened with respect to the first threaded portion 23a with the jig 40 in contact with the main body contact portion 4.

To reliably and safely suppress co-rotation of a screw drive unit when performing a tightening and loosening operation for a threaded fastener which fixes a screw to the screw drive unit. Provided is an injection molding machine 2 in which a threaded fastener 30 is tightened into a first threaded portion 23a of a screw drive unit 21, thereby fixing a screw 10 to the screw drive unit 21 through a fixation bush 25, wherein a jig 40, which is detachably mounted on the screw drive unit 21, and is brought into contact with a main body contact portion 4 of a main body portion 3 of the injection molding machine 2 by rotating the screw drive unit 21 to restrict further rotation of the screw drive unit 21, is mounted on the screw drive unit 21, and the threaded fastener 30 is tightened or loosened with respect to the first threaded portion 23a with the jig 40 in contact with the main body contact portion 4.

A control device for an injection molding machine including a cylinder into which a resin is supplied and a screw that moves forward and rearward and rotates inside the cylinder, includes a metering control unit that performs metering of the resin inside the cylinder by controlling forward rotation and rearward movement of the screw until the screw has been moved rearward to a predetermined metering position, based on predetermined metering conditions, a rearward movement speed acquisition unit acquiring a rearward movement speed of the screw, a speed determination unit that determines a suck back speed for causing a resin pressure to reach a target pressure, based on the rearward movement speed acquired during metering by the rearward movement speed acquisition unit, and a suck back control unit causing the screw to move further rearward based on the suck back speed, after the screw has reached the predetermined metering position.