A method for monitoring the hydraulic supply system of a plastic processing machine. In order to monitor the state of the hydraulic system without great effort, the method includes the following steps: a) Prior to operation of the machine: Determination of the nominal flow rate of a hydraulic pump as a function of an operating parameter of the hydraulic pump and determination of the nominal displacement speed of the hydraulically driven axis when a piston-cylinder element is acted upon by a predetermined nominal flow rate; b) During operation of the machine: When the hydraulically driven axis is operated: measuring the at least one operating parameter of the hydraulic pump as well as the actual displacement speed of the hydraulic axis and comparing the actual displacement speed with the nominal displacement speed resulting from the previously measured operating parameter of the hydraulic pump, and outputting the result of the comparison.

An injection blow molding apparatus comprises: a first oil supply section which has a hydraulic drive source composed of a drive motor, whose number of revolutions can be controlled, and a hydraulic pump and which supplies oil from an oil tank to an injection mold drive unit provided in an injection mold unit; and a second oil supply section which has a hydraulic drive source composed of a drive motor, whose number of revolutions can be controlled, and a hydraulic pump and which supplies oil from the oil tank to a blow mold drive unit provided in a blow mold unit, the second oil supply section being provided independently of the first oil supply section.

An injection blow molding apparatus comprises: a first oil supply section which has a hydraulic drive source composed of a drive motor, whose number of revolutions can be controlled, and a hydraulic pump and which supplies oil from an oil tank to an injection mold drive unit provided in an injection mold unit; and a second oil supply section which has a hydraulic drive source composed of a drive motor, whose number of revolutions can be controlled, and a hydraulic pump and which supplies oil from the oil tank to a blow mold drive unit provided in a blow mold unit, the second oil supply section being provided independently of the first oil supply section.

An injection blow molding apparatus comprises: a first oil supply section 100A which has a hydraulic drive source composed of a drive motor, whose number of revolutions can be controlled, and a hydraulic pump and which supplies oil from an oil tank 90 to an injection mold drive unit 72 provided in an injection mold unit 70; and a second oil supply section 100B which has a hydraulic drive source composed of a drive motor, whose number of revolutions can be controlled, and a hydraulic pump and which supplies oil from the oil tank 90 to a blow mold drive unit 42 provided in a blow mold unit 41, the second oil supply section 100B being provided independently of the first oil supply section 100A.

An injection blow molding apparatus comprises: a first oil supply section 100A which has a hydraulic drive source composed of a drive motor, whose number of revolutions can be controlled, and a hydraulic pump and which supplies oil from an oil tank 90 to an injection mold drive unit 72 provided in an injection mold unit 70; and a second oil supply section 100B which has a hydraulic drive source composed of a drive motor, whose number of revolutions can be controlled, and a hydraulic pump and which supplies oil from the oil tank 90 to a blow mold drive unit 42 provided in a blow mold unit 41, the second oil supply section 100B being provided independently of the first oil supply section 100A.

A control method for a mold opening/closing device including a hydraulic cylinder that opens and closes a mold, a hydraulic drive device that drives the hydraulic cylinder by supplying a hydraulic oil, and a controller that controls the hydraulic drive device, wherein the controller changes speed change in a deceleration region, in which movement of the hydraulic cylinder is decelerated, between a first half portion and a second half portion of the deceleration region, and causes speed change rate per unit time in the second half portion to be smaller than in the first half portion.

A control method for a mold opening/closing device including a hydraulic cylinder that opens and closes a mold, a hydraulic drive device that drives the hydraulic cylinder by supplying a hydraulic oil, and a controller that controls the hydraulic drive device, wherein the controller changes speed change in a deceleration region, in which movement of the hydraulic cylinder is decelerated, between a first half portion and a second half portion of the deceleration region, and causes speed change rate per unit time in the second half portion to be smaller than in the first half portion.

A mold-clamping device includes a fixed mold plate including a fixed mold; a movable mold plate including a movable mold; a hydraulic cylinder allowing the movable mold plate to approach or be separated from the fixed mold plate; a hydraulic pressure supply source supplying a hydraulic fluid to the hydraulic cylinder; and a control unit performing driving control on the hydraulic pressure supply source. The control unit includes a flow rate decrease control unit for deceleration for decreasing a flow rate of the hydraulic fluid according to a deceleration gradient set in advance when a movement of the movable mold plate is decelerated according to the deceleration gradient, and a flow rate increase control unit for controlling the flow rate of the hydraulic fluid to increase when the flow rate of the hydraulic fluid is decreased according to the deceleration gradient by the flow rate decrease control unit.

A mold-clamping device includes a fixed mold plate including a fixed mold; a movable mold plate including a movable mold; a hydraulic cylinder allowing the movable mold plate to approach or be separated from the fixed mold plate; a hydraulic pressure supply source supplying a hydraulic fluid to the hydraulic cylinder; and a control unit performing driving control on the hydraulic pressure supply source. The control unit includes a flow rate decrease control unit for deceleration for decreasing a flow rate of the hydraulic fluid according to a deceleration gradient set in advance when a movement of the movable mold plate is decelerated according to the deceleration gradient, and a flow rate increase control unit for controlling the flow rate of the hydraulic fluid to increase when the flow rate of the hydraulic fluid is decreased according to the deceleration gradient by the flow rate decrease control unit.

An injection moulding system, water jet cutting machine or other industrial system has a synthetically controlled variable displacement fluid working machine which outputs hydraulic fluid to one or more fluid consumers, such as rams or hydraulic motors, through hydraulically stiff fluid retaining volumes and receives hydraulic fluid back from one or more fluid consumers through the same or other said hydraulically stiff fluid retaining volumes. Individual piston cylinder assemblies can be allocated to different outputs. There may be no valve between the machine and the consumers. A working chamber of the machine can be caused to undergo a motoring cycle to enable the machine to output more power than is received from a motor driving the machine. An accumulator can be used to provide a source of hydraulic compliance. The machine can be controlled using pressure control, flow control, feed forward control or variable power/variable power limit control.