Control system of machine tool

A control system of a machine tool which machines a work, the control system comprising:

• a control device which controls a drive axis of the machine tool based on speed control data;
• a machined surface measurement device which measures a machined surface of the work;
• and
• an analysis device which analyzes failures on the machined surface of the work,
• wherein the analysis device includes:
• a first acquisition portion which acquires, from the control device, the chronological speed control data when the work is machined;
• a second acquisition portion which acquires spatial machined surface measurement data after the machining of the work measured by the machined surface measurement device;
• a data-associating processing portion which associates the chronological speed control data acquired by the first acquisition portion and the spatial machined surface measurement data acquired by the second acquisition portion with each other;
• a machined surface failure detection portion which detects the failures on the machined surface of the work and the locations thereof based on the spatial machined surface measurement data acquired by the second acquisition portion;
• an identification portion which identifies, based on the speed control data and the machined surface measurement data associated by the data-associating processing portion, the speed control data of the failure locations corresponding to the machined surface measurement data of the failure locations detected by the machined surface failure detection portion;
• a failure interval detection portion which detects an interval of the failures detected by the machined surface failure detection portion;
• and
• a calculation portion which determines a speed in a direction of the machining based on the speed control data of the failure locations identified by the identification portion and which calculates, based on the determined speed and the interval of the failures detected by the failure interval detection portion, a frequency of vibrations of the machine tool that cause the failures.