An injection molding machine is equipped with a screw having a spline shaft formed with a spline on an outer circumferential surface, a bush having a spline hole formed with a spline on an inner circumferential surface, a linear motion motor for moving the bush in an axial direction of the screw, a rotational motion motor for rotating the bush about an axis of the screw, and a motor control unit which, in the case of fitting the spline shaft in the spline hole, controls the linear motion motor to advance the bush in a direction approaching the screw in a state that the bush and the screw are separated, and which controls the rotational motion motor to rotate the bush when the acquired output torque becomes equal to or larger than a first predetermined torque.

Injection molding of plastic materials by an apparatus comprising at least one injector including a valve pin displaceable in a controlled manner between a closed position and an open position by an electric rotary actuator. At least one step is provided of detecting the value of the torque developed by the electric rotary actuator when the valve pin is in the path from the closed position to the open position, and the torque value detected is used to pilot the molding process.

A technique for providing assistance in setting the time to increase the clamping force is provided. A control device of an injection molding machine includes a clamping control part and a monitoring part. The clamping control part is configured to change, in a filling step of filling the inside of a mold device with a molding material during clamping, a set value of clamping force from a first set value to a second set value that is larger than the first set value, at a predetermined pressurizing timing in the middle of the filling step. The monitoring part is configured to monitor changes in the actual value of the clamping force due to changes in the set value of the clamping force.

Injection molding of plastic materials by an apparatus comprising at least one injector including a valve pin displaceable in a controlled manner between a closed position and an open position by an electric rotary actuator. At least one step is provided of detecting the value of the torque developed by the electric rotary actuator when the valve pin is in the path from the closed position to the open position, and the torque value detected is used to pilot the molding process.

In a method for operating an injection moulding machine in the absence of a backflow barrier, plastic melt is injected by a plasticising device into a cavity in a screw antechamber of a plasticising screw adapted to rotate about a longitudinal axis and to move translationally by a drive unit during an injection phase and a holding- pressure phase. A rotational drive of the drive unit is controlled such that a speed of the plasticising screw causes overlay of a backflow of the plastic melt from the screw antechamber back into screw threads of the plasticising screw by an opposing delivery flow as a result of a rotation of the plasticising screw due to a translational injection movement of the plasticising screw. A differential flow is established from the backflow and the opposing delivery flow and influenced at least during the injection phase by influencing the speed of the plasticising screw.

Injection molding of plastic materials by an apparatus comprising at least one injector including a valve pin displaceable in a controlled manner between a closed position and an open position by an electric rotary actuator. At least one step is provided of detecting the value of the torque developed by the electric rotary actuator when the valve pin is in the path from the closed position to the open position, and the torque value detected is used to pilot the molding process.

The present disclosure prevents load from being produced in an injection molding machine. The control device for an injection molding machine according to one embodiment of the present disclosure has a determining part that is configured to determine, based on information detected in accordance with a movement of a measurement motor provided in the injection molding machine, whether or not an operation of removing or attaching a screw that rotates in accordance with the measurement motor has been performed.