Numerical control system

A numerical control system comprising:

• detecting circuitry to obtain cutting force generated in a machine tool;
• controlling circuitry to calculate a control amount according to a cutting condition and to control a feed drive mechanism of the machine tool;
• a dynamic-characteristics-information storage to store dynamic characteristics information of a tool or a workpiece, in relation to the cutting condition;
• a machining-process-information storage to store information representing a machining process to occur between the tool and the workpiece, in relation to the cutting condition;
• countermeasure determining circuitry to, when it is detected from the cutting force or a state of the feed drive mechanism of the machine tool that a machining defect has occurred, calculate a plurality of deviation degrees for possible causes of the machining defect, and compare the calculated deviation degrees and to thereby determine a cause of the machining defect whose occurrence has been detected;
• and
• correction-amount calculating circuitry to calculate, according to the cause of the machining defect determined by the countermeasure determining circuitry, a correction amount with respect to the control amount, and then output the correction amount to the controlling circuitry.