Machine tool
In a machine tool, when machining is in a steady zone, a rotation phase of a main spindle at the time of measurement in the N-th sampling is calculated, and the calculated rotation phase and the measurement value are recorded in a recording section so as to be associated with each other. The measurement and calculation of the rotation phase of the main spindle at the time of each measurement are continued for plural times of rotations of the main spindle, and thus the measurement values are obtained at various rotation phases, whereby change in drive force during one rotation of the main spindle is finally calculated.
1. A machine tool comprising:
a rotary shaft device including a rotary shaft;
a sensor attached to the rotary shaft device and configured to acquire information about a phenomenon periodically occurring on the rotary shaft device in synchronization with rotation of the rotary shaft; and
a control device configured to control operation of the rotary shaft device and acquire the information via the sensor, wherein
when machining is performed while the rotary shaft is rotated, the control device determines whether or not the machining is in a steady state in which there is no change in a command relevant to operation control for the rotary shaft device, and
when the machining is in the steady state, the control device acquires the information via the sensor with a predetermined sampling cycle, associates the acquired information with a rotation phase of the rotary shaft, and calculates change in the phenomenon in one cycle on the basis of the information acquired for plural times of rotations of the rotary shaft.
2. A machine tool comprising:
a rotary shaft device including a rotary shaft;
a sensor attached to the rotary shaft device and configured to acquire information about a phenomenon periodically occurring on the rotary shaft device in synchronization with rotation of the rotary shaft; and
a control device configured to control operation of the rotary shaft device and acquire the information via the sensor, wherein
when machining is performed while the rotary shaft is rotated, the control device determines whether or not the machining is in a steady state in which there is no change in machining state, and
when the machining is in the steady state, the control device acquires the information via the sensor with a predetermined sampling cycle, associates the acquired information with a rotation phase of the rotary shaft, and calculates change in the phenomenon in one cycle on the basis of the information acquired for plural times of rotations of the rotary shaft.
3. The machine tool according to claim 2 , wherein
a tool or a workpiece is mounted to the rotary shaft, and
a cutting amount of the workpiece is calculated from information about a preset shape of the workpiece, an operation path of the tool relative to the workpiece, and a current command coordinate, and the machining is determined to be in the steady state on the basis of a fact that the cutting amount is constant.