Patent ID: 8374717

Claim:
A method of suppressing chatter vibration of a machine tool during machining of a workpiece, the machine tool being provided with a rotary shaft for rotating a tool or the workpiece, assuming that a decimal part of a value obtained by a following formula: 60×Chatter frequency/(Number of Tool flutes×Rotation speed of Rotary shaft) is given as phase information, the method comprising: a first step of attaching the tool to the rotary shaft and computing a modal parameter of the tool or the workpiece; a second step of calculating a relation between chatter frequency and the phase information as an approximation formula based on the modal parameter and machining conditions; a third step of detecting time-domain vibration caused by the chatter vibration; a fourth step of calculating a chatter frequency and a frequency-domain characteristic value of the chatter frequency based on the vibration detected in the third step; and a fifth step of obtaining a chatter frequency corresponding to the phase information that has been selected as a target using the approximation formula if the characteristic value calculated in the fourth step exceeds a predetermined threshold value, and thereafter calculating an optimum rotation speed using the obtained chatter frequency and the number of tool flutes.