Control of pressure injection moulding machine opening and closure

摘要

The control method is devised for a pressure injection moulding machine. The system includes a control valve (4) for a hydraulic cylinder (15) driving an object e.g. the moving mould platen (2). A signal (Cs) is sent from the control unit (5) to the control valve (4), which varies the movement. In the new method, along the path of motion of the platen, including a zone of acceleration (Vca), speed control is carried out in open circuit. The signal to the valve is based on a speed error value. In a zone of motion including a deceleration region, the control signal supplied to the valve is derived from closed circuit control. This signal is based on the difference between a detected speed value and a speed error value.