Method of deciding the quality of resin workpiece in a compression-molding process

A method of controlling a compression-molding press in compression-molding a resin workpiece on the compression-molding press which compression-molds the resin workpiece in a cavity formed between a pair of molds by moving at least one of the pair of molds by the hydraulic cylinder actuators, said method comprising the steps of:

• moving said at least one of said pair of molds such that the resin workpiece in the cavity is spread and fills up the cavity;
• detecting a value of a press characteristic indicative of workpiece quality when the moving mold passes a predetermined position, said position corresponding to a time during which the resin workpiece is spread to fill up the cavity;
• comparing the detected value with a predetermined optimum value of the press characteristic when the moving mold passes the position, to determine a deviation between said detected value and said optimum value;
• deciding the quality of the resin workpiece on the basis of the deviation;
• and
• performing one of a step of interrupting the compression-molding operation when it is decided that the quality of the resin workpiece is nonconforming and a step of executing a control operation to add a predetermined correction corresponding to the deviation to the press characteristic when it is decided that the quality of the resin workpiece is conforming.