Abstract: A machine tool in which a tool holder having a tool is attached to a main spindle and the main spindle is rotated to conduct machining on a workpiece, comprises: a displacement sensor, the impedance of which is changed according to a distance from the displacement sensor to the tool holder, an AC signal being impressed upon the displacement sensor from an amplifying unit, wherein an abnormality of a state, in which the tool holder is attached to the main spindle, is judged from a signal level appearing in the displacement sensor. The machine tool further comprises: a tuning circuit connected to the displacement sensor, the tuning circuit composing a resonance circuit together with the displacement sensor; and an impedance adjustment circuit for adjusting an internal impedance constant of the tuning circuit.

Abstract: A method and a device for detecting the incorrect chucking of a machine tool capable of easily and surely detecting a chucking error; the method, comprising the steps of measuring, by a sensor (12), the change of a distance (d) between the sensor (12) and the outer peripheral surface of the flange part (2B) of a tool holder (2) installed in a spindle (3) through all around the periphery of the tool holder while rotating the tool holder (2), performing a FFT analysis of the measured data by a CPU (18), extracting a fundamental frequency component, and calculating the amplitude thereof, whereby the eccentric amount of the tool holder (2) can be calculated by using the amplitude of the fundamental frequency component and, when the eccentric amount exceeds a preset allowable value, the tool holder (2) is judged to cause an incorrect chucking.

Abstract: A machine tool in which a tool holder having a tool is attached to a main spindle and the main spindle is rotated to conduct machining on a workpiece, comprises: a displacement sensor, the impedance of which is changed according to a distance from the displacement sensor to the tool holder, an AC signal being impressed upon the displacement sensor from an amplifying unit, wherein an abnormality of a state, in which the tool holder is attached to the main spindle, is judged from a signal level appearing in the displacement sensor. The machine tool further comprises: a tuning circuit connected to the displacement sensor, the tuning circuit composing a resonance circuit together with the displacement sensor; and an impedance adjustment circuit for adjusting an internal impedance constant of the tuning circuit.

Abstract: A method and a device for detecting the incorrect chucking of a machine tool capable of easily and surely detecting a chucking error; the method, comprising the steps of measuring, by a sensor (12), the change of a distance (d) between the sensor (12) and the outer peripheral surface of the flange part (2B) of a tool holder (2) installed in a spindle (3) through all around the periphery of the tool holder while rotating the tool holder (2), performing a FFT analysis of the measured data by a CPU (18), extracting a fundamental frequency component, and calculating the amplitude thereof, whereby the eccentric amount of the tool holder (2) can be calculated by using the amplitude of the fundamental frequency component and, when the eccentric amount exceeds a preset allowable value, the tool holder (2) is judged to cause an incorrect chucking.

Abstract: A method and a device for detecting the incorrect chucking of a machine tool capable of easily and surely detecting a chucking error; the method, comprising the steps of measuring, by a sensor (12), the change of a distance (d) between the sensor (12) and the outer peripheral surface of the flange part (2B) of a tool holder (2) installed in a spindle (3) through all around the periphery of the tool holder while rotating the tool holder (2), performing a FFT analysis of the measured data by a CPU (18), extracting a fundamental frequency component, and calculating the amplitude thereof, whereby the eccentric amount of the tool holder (2) can be calculated by using the amplitude of the fundamental frequency component and, when the eccentric amount exceeds a preset allowable value, the tool holder (2) is judged to cause an incorrect chucking.

Abstract: A method and a device for detecting the incorrect chucking of a machine tool capable of easily and surely detecting a chucking error; the method, comprising the steps of measuring, by a sensor (12), the change of a distance (d) between the sensor (12) and the outer peripheral surface of the flange part (2B) of a tool holder (2) installed in a spindle (3) through all around the periphery of the tool holder while rotating the tool holder (2), performing a FFT analysis of the measured data by a CPU (18), extracting a fundamental frequency component, and calculating the amplitude thereof, whereby the eccentric amount of the tool holder (2) can be calculated by using the amplitude of the fundamental frequency component and, when the eccentric amount exceeds a preset allowable value, the tool holder (2) is judged to cause an incorrect chucking.