METHOD FOR CONTROLLING SPEED OF COMPRESSION MOLDING PRESS

PURPOSE:To perform precise molding by performing control accurately according to a set speed by performing correction corresponding to the pressure variation in a cylinder considering the compressibility of hydraulic oil. CONSTITUTION:The moving speed pattern of a slider 3 is preliminarily inputted and set to a controller 14 and the flow rate set value Q0 of the hydraulic oil to be supplied to main and auxiliary cylinders 5, 6 is calculated from a speed set value (v) according to Q0=A.v (A is the cross-sectional area of the main and auxiliary cylinders). As a result, the slider 3 is moved at a set speed of v=Q0/A. When the slider 3 falls and the compression of a resin A is started in an upper mold 8, the internal pressures in the main and auxiliary cylinders 5, 6 rise. Herein, said pressures are detected by a pressure detector 13 to calculate pressure variation quantity and, further, a corrected flow rate and a flow rate order value Q are calculated in the controller 14. Then, hydraulic oil of a flow rate Q is supplied to the main and auxiliary cylinders 5, 6. By this method, the volumetric reduction of the hydraulic oil by pressure variation is corrected and the slider 3 is moved at the set speed (v).