A numerical controller for controlling a machine tool including a spindle motor formed of an induction motor includes: a storage unit that stores a maximum acceleration at which the spindle motor can operate when a magnetic flux amount of the spindle motor reaches its maximum; a magnetic flux amount acquisition unit that acquires a present magnetic flux amount of the spindle motor; and an acceleration change unit that changes an acceleration of a position command based on a maximum acceleration of the spindle motor stored in the storage unit according to a magnetic flux amount at the start of movement of the spindle motor acquired by the magnetic flux amount acquisition unit when the spindle motor is operated by position control using a position command.

Provided is a carbon fiber reinforced plastic machining method using CAM which includes the step (S10) of determining machining grade in accordance with a machining target and the step (S20) of determining machining grade in accordance with a machining process, in which the machining grade is a processing condition which is determined in accordance with the rotational speed and the feeding speed of a spindle as a machining tool.

A controller for controlling a synchronized operation of spindle and feed axes. A spindle-axis control section includes a section for making a spindle axis perform an accelerated rotation at maximum capacity from a process start position; sections for respectively detecting a maximum acceleration, a residual rotation amount and a current speed of the spindle axis; a section for making the spindle axis perform a decelerated rotation at maximum capacity to reach a target thread depth after the accelerated rotation; and a section for executing a torque-limiting during the accelerated rotation of the spindle axis, in such a manner that a torque command lower than a maximum torque command is given to the spindle axis at a start of acceleration, and thereafter the torque command is gradually increased so that the maximum torque command is given to the spindle axis when a predetermined time has elapsed.

An apparatus for detecting the status of a tool in a machine tool may include: a sensor unit configured to sense acceleration of a spindle of the machine tool in an x-axis direction and a y-axis direction during processing; and a processing device configured to convert the x-axis signal and the y-axis signal, sensed by the sensor unit, into signals capable of representing a cutting force by processing the x-axis and y-axis signals, detect a resultant force, and plot the detected resultant force on a polar coordinate system.

A controller for controlling a synchronized operation of spindle and feed axes. A spindle-axis control section includes an initial-motion control section for accelerating a spindle axis at maximum capacity from a starting position; a maximum-acceleration detecting section for detecting a maximum acceleration of the spindle axis; a residual rotation-amount detecting section for detecting a residual rotation amount of the spindle axis; a current-speed detecting section for detecting a current speed of the spindle axis; a decelerating-motion control section for decelerating the spindle axis to reach an intermediate speed, after the acceleration; a positioning-motion control section for decelerating the spindle axis to reach the target position after reaching the intermediate speed; a flux-content predicting section for predicting an actual motor-flux content at the intermediate speed; and a deceleration determining section for determining a deceleration for a positioning operation, based on the maximum acceleration, the motor-flux-content command value and the motor-flux content.

Provided is a numerical control device that eliminates the need for rapid acceleration/deceleration of a cutting tool during boring and that is capable of minimizing vibration of a machine tool. This numerical control device comprises: a deep hole boring execution unit which performs deep hole boring by repeating a cutting operation for making a cut in a workpiece while rotating the cutting tool and a cutting halting operation for halting the cutting operation of the workpiece while rotating the cutting tool; and a chip-discharging time calculation unit which calculates a chip discharging time depending on the position of the cutting tool after each cut during the cutting operation. The deep hole boring execution unit performs the cutting halting operation during the chip-discharging time.

A controller for controlling a synchronized operation of spindle and feed axes. A spindle-axis control section includes an initial-motion control section for making a spindle axis perform an accelerated rotation at maximum capacity from a process start position; a maximum-acceleration detecting section for detecting a maximum acceleration of the spindle axis; a residual rotation-amount detecting section for detecting a residual rotation amount of the spindle axis; a current-speed detecting section for detecting a current speed of the spindle axis; a positioning-motion control section for making the spindle axis perform a decelerated rotation so as to reach the target thread depth after the accelerated rotation; and an overshoot detecting section for detecting an overshoot of the spindle axis during the decelerated rotation.

Provided is a control device for a machine tool capable of reducing adverse effects due to rapid changes in periodic fluctuations in the rotation speed of a main spindle while maintaining an effect of suppressing regenerative self-excited chatter vibration. This control device for a machine tool includes a fluctuation command calculation unit configured to calculate a fluctuation command based on a speed command for a main spindle motor of the machine tool and a fluctuation condition for causing a rotation speed of the main spindle motor to periodically fluctuate, and a speed control unit configured to control the rotation speed of the main spindle motor based on the speed command and the fluctuation command. The fluctuation command calculation unit is configured to calculate, when the fluctuation condition is changed, the fluctuation command in which an amplitude of the rotation speed that periodically fluctuates and/or a frequency of the rotation speed that periodically fluctuates gradually changes.