In one aspect, there is provided an injection molding system configured to operate in a plurality of cycles. The system comprises, amongst other things, a controller that is configured for performing a comparison of a variable pressure setpoint with a target pressure value. The controller is configured to, when the target pressure value is less than the variable pressure setpoint by at least a predetermined lower bound, (i) decrease the variable pressure setpoint to a reduced variable pressure setpoint and (ii) not further decrease the variable pressure setpoint from the reduced variable pressure setpoint until the pump assembly operates for a plurality of stabilizing cycles at the reduced variable pressure setpoint.

In one aspect, there is provided an injection molding system configured to operate in a plurality of cycles. The system comprises, amongst other things, a controller that is configured for performing a comparison of a variable pressure setpoint with a target pressure value. The controller is configured to, when the target pressure value is less than the variable pressure setpoint by at least a predetermined lower bound, (i) decrease the variable pressure setpoint to a reduced variable pressure setpoint and (ii) not further decrease the variable pressure setpoint from the reduced variable pressure setpoint until the pump assembly operates for a plurality of stabilizing cycles at the reduced variable pressure setpoint.

The invention relates to a hydraulic device for supplying a plurality of work units (3a, 3b), in particular on a plastics injection moulding machine, said device comprising at least one controller (7), at least one valve regulator and/or one valve controller and a central drive (1). A regulating valve (13a, 13b) with a regulating-valve geometry is provided on at least one of the work units (3a, 3b). Pressure sensors (8) detect at least one pressure both upstream and downstream of the regulating valve (13a, 13b), the load pressure (10a, 10b) of at least one of the work units (3a, 3b), and the system pressure (9). Since the valve regulator and/or the valve controller has knowledge about the regulating-valve geometry of the at least one regulating valve (13a, 13b) and is designed to derive, from a relationship between the regulating-valve geometry and at least one pressure difference resulting from the pressures detected upstream and downstream of the regulating valve (13a, 13b), at least one volume flow rate actual value per regulating valve (13a, 13b), and the controller (7) is designed to derive, from the volume flow rate setpoint values of the at least one work unit (3a, 3b) and/or the volume flow rate actual values of the at least one regulating valve (13a, 13b), at least one setpoint value feedforward control for the central drive (1) in such a way that the system pressure (9) corresponds at least to the relevant highest load pressure (10a, 10b) of the work units (3a, 3b), the hydraulic device is improved in terms of functionality, energy, efficiency and economy.

An injection molding system configured to operate in a plurality of cycles includes, amongst other things, a controller that is configured for performing a comparison of a variable pressure setpoint with a target pressure value. The controller is configured to, when the target pressure value is less than the variable pressure setpoint by at least a predetermined lower bound, (i) decrease the variable pressure setpoint to a reduced variable pressure setpoint and (ii) not further decrease the variable pressure setpoint from the reduced variable pressure setpoint until the pump assembly operates for a plurality of stabilizing cycles at the reduced variable pressure setpoint.

Disclosed is a hydraulic system for a molding system, the molding system having a clamp actuator and an injection actuator, the hydraulic system comprising a clamp accumulator for storing hydraulic fluid for use in actuating the clamp actuator; an injection accumulator for storing hydraulic fluid for use in actuating the injection actuator; a pump for conveying hydraulic fluid to the clamp accumulator and the injection accumulator; and a selector valve for selectively fluidly connecting the pump to one of the clamp accumulator and the injection accumulator.