Provided are a control device and a control method for a machine tool which are capable of further reducing a command-waiting time. This control device for a machine tool which controls synchronized operation of a main shaft and a feed shaft comprises: a numerical value control unit; a main shaft control unit; a rotation detection unit. The numerical value control unit has a main shaft command output unit which, when a cutting operation and pulling-out operation are carried out from a machining start position to a target position an arbitrary number of times, acquires from the tapping program the rotation amount and the maximum rotation speed of the main shaft in the cutting operation and pulling-out operation and which supplies the rotation amount and the maximum rotation speed of the main shaft to the main shaft control unit as the main shaft command.

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 from a starting position; a maximum-acceleration detecting section for detecting a maximum acceleration of the spindle axis during acceleration; 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; and a torque-command limiting section for limiting a fluctuation of a torque command of the position control, instructed to the spindle axis, to a predetermined range over a period until a predetermined elapse condition is satisfied after reaching the intermediate speed.

A synchronous control device (10) includes a spindle control part (11a) and a driven shaft control part (11b). The driven shaft control part (11b) includes a driven shaft command position variation suppression part (114) which generates as a driven shaft command phase (Ps) a projected driven shaft command phase obtained by adding an advance angle amount (Pa) corresponding to a spindle speed to a spindle phase (Pm) in a case where a sign of the spindle speed is reverse from a previous period, and generates as the driven shaft command phase (Ps) a value in which a sign of a shift from the driven shaft command phase in the previous period is not reverse from the sign of the spindle speed in a predetermined case where the sign of the spindle speed is not reverse from the previous period.

A controller controlling a synchronized operation of spindle and feed axes. A positioning-motion control section of a spindle-axis control section calculates a first velocity command making a spindle axis perform a decelerated rotation at a variable deceleration lower than a maximum deceleration during an acceleration-varying time just after the spindle axis reaches an intermediate speed or just before the spindle axis reaches a target position, and making the spindle axis perform the decelerated rotation at the maximum deceleration during a time except for the acceleration-varying time; calculates a second velocity command making the spindle axis perform a decelerated rotation at a constant deceleration lower than the maximum deceleration after the spindle axis reaches the intermediate speed; and chooses either one, achieving a lower speed, of the first and second velocity command during a period when the spindle axis operates from the intermediate speed to reach the target position.

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 from a starting position; a maximum-acceleration detecting section for detecting a maximum acceleration of the spindle axis during acceleration; 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; and a torque-command limiting section for limiting a fluctuation of a torque command of the position control, instructed to the spindle axis, to a predetermined range over a period until a predetermined elapse condition is satisfied after reaching the intermediate speed.

A synchronous control device (10) includes a spindle control part (11a) and a driven shaft control part (11b). The driven shaft control part (11b) includes a driven shaft command position variation suppression part (114) which generates as a driven shaft command phase (Ps) a projected driven shaft command phase obtained by adding an advance angle amount (Pa) corresponding to a spindle speed to a spindle phase (Pm) in a case where a sign of the spindle speed is reverse from a previous period, and generates as the driven shaft command phase (Ps) a value in which a sign of a shift from the driven shaft command phase in the previous period is not reverse from the sign of the spindle speed in a predetermined case where the sign of the spindle speed is not reverse from the previous period.

A controller controlling a synchronized operation of spindle and feed axes. A positioning-motion control section of a spindle-axis control section calculates a first velocity command making a spindle axis perform a decelerated rotation at a variable deceleration lower than a maximum deceleration during an acceleration-varying time just after the spindle axis reaches an intermediate speed or just before the spindle axis reaches a target position, and making the spindle axis perform the decelerated rotation at the maximum deceleration during a time except for the acceleration-varying time; calculates a second velocity command making the spindle axis perform a decelerated rotation at a constant deceleration lower than the maximum deceleration after the spindle axis reaches the intermediate speed; and chooses either one, achieving a lower speed, of the first and second velocity command during a period when the spindle axis operates from the intermediate speed to reach the target position.

A machine tool controller including a numerical control section, a spindle-axis control section and a feed-axis control section. The spindle-axis control section includes a section for making the spindle axis perform an accelerated rotation at maximum capacity from a process start position toward a target thread depth, with a maximum rotation speed set as a target value; a section for detecting a maximum acceleration during the accelerated rotation based on a rotational position; a section for detecting a residual rotation amount from a current position to the target thread depth, based on a total rotation amount and the rotational position; a section for detecting a current speed based on the rotational position; and a section for making the spindle axis perform a decelerated rotation at maximum capacity to reach the target thread depth after the accelerated rotation, based on the maximum acceleration, the residual rotation amount and the current speed.

Provided are a control device and a control method for a machine tool which are capable of further reducing a command-waiting time. This control device for a machine tool which controls synchronized operation of a main shaft and a feed shaft comprises: a numerical value control unit; a main shaft control unit; a rotation detection unit. The numerical value control unit has a main shaft command output unit which, when a cutting operation and pulling-out operation are carried out from a machining start position to a target position an arbitrary number of times, acquires from the tapping program the rotation amount and the maximum rotation speed of the main shaft in the cutting operation and pulling-out operation and which supplies the rotation amount and the maximum rotation speed of the main shaft to the main shaft control unit as the main shaft command.