A controller of an injection molding machine stores used/unused information in relation to each of the maximum number of controllable servo amplifiers, outputs an interruption request signal requesting power interruption in a lump to apart of or all of these plurality of servo amplifiers, and receives a power interruption confirmation signal confirming that the motor power of the servo amplifiers is interrupted. Further, the controller determines, on the basis of the interruption request signal, the power interruption confirmation signal and the used/unused information, whether or not interruption driving the servo motor is normally operated.

A method is described for operating an injection moulding machine, which has one or more movable machine parts which can be moved by suitable drives along specifiable travelling distances. Movement of a movable machine part is repeated cyclically. In order to reduce the movement times of the movable machine parts to a minimum, provision is made for one or more of the movable machine parts to successively reduce the power reserves of one or more of the drives associated with a movable machine part, until a specifiable minimum of power reserve is reached, wherein the minimum can be zero. In each cycle, the power reserve of the drive or drives is determined and is successively reduced, in particular from cycle to cycle. A movable platen, an ejector, a core puller, a plasticizing screw and/or an injection piston can be provided as movable machine part.

A heater which is adaptable to an electric energy which permits a power source voltage expected at an arbitrary place of use is selected and is attached to an injection molding machine in advance. When the injection molding machine is installed at the place of use, the power source voltage of a power source is obtained, as an actual power source voltage, directly or indirectly by a molding machine controller provided in the injection molding machine, an energization gradient ratio is calculated, as a conversion factor, on the basis of the ratio of the actual power source voltage to the rated voltage of the heater provided in the injection molding machine, and supply power to the heater is controlled by a power distribution process of multiplying a controlled variable associated with the heater by the conversion factor.

A system is described comprising an actuator with a piston linearly movable and a needle shutter connected to the piston for regulating the injection flow of molten material from a nozzle into a mold. By a supply circuit pressurized fluid is brought to the piston to move it back and forth. A solenoid valve is connected to the supply circuit and configured so that in resting condition it leaves open a fluid drainage path for bringing the shutter to a closing position.