Hydraulic control method for hydraulic press

A hydraulic control method for a hydraulic press in which a plurality of pressure cylinders are disposed along an axis of a slide of the hydraulic press, individual ones the pressure cylinders being capable of being selectively pressurized under control of a servo valve so that a press motion curve of the hydraulic press can be made to match press motion curves of a plurality of different mechanical presses when making metal molds, the method comprising the steps of:

• accumulating hydraulic oil in an accumulator, the oil capable of being transmitted by a pump unit to any one of the plurality of pressure cylinders under the control of the servo valve;
• selectively opening a directional valve associated with each one of the pressure cylinders to be selectively pressurized so that different predetermined amounts of oil can be supplied to each one of the pressure cylinders to be pressurized;
• and
• controlling a position and speed of the slide of the hydraulic press by the servo valve, the servo valve operating based on a first input determined by a predetermined one of the plurality of different mechanical presses to be matched and a second input from a slide position detector, the second input providing an actual position of the slide of the hydraulic press,
• wherein the controlling step makes it possible to match the press motion curve of the hydraulic press with the press motion curve of any of the plurality of different mechanical presses.