Command data indicating a command path of a tool is generated on the basis of tool data created on the basis of an inclination and a shape of the tool, and interpolation data for each interpolation period is generated and outputted. When a command block is a block commanding skiving processing, correction data for correcting the command path is generated on the basis of the tool data stored in the tool data storage unit, and the correction data corresponding to interpolation data outputted by an interpolation unit is outputted.

In order to improve a method for positioning a centre point of a second machine tool unit of a machine tool on a geometric axis of a first machine tool unit of the machine tool, wherein the second machine tool unit has a circular path concentric with the centre point, and wherein the first machine tool unit has a component that is rotatable about the geometric axis, in such a way that said method can be performed by an operator easily, reliably and within a short timeframe, it is proposed that a measuring unit is arranged in a defined manner relative to the geometric axis and the position of the circular path relative to the geometric axis is established using the measuring unit, that the position of the centre point of the circular path in the geometric plane relative to the geometric axis is calculated, and that adjustment paths in the geometric plane, which are associated with the adjustment directions, for positioning the centre point on the geometric axis are calculated, and that the machine tool units are moved relative to one another in accordance with these adjustment paths.

In a machine tool and a control apparatus thereof, a repetitive movement unit is configured so that the cutting tool performs one repetitive movement with respect to multiple relative rotations between the workpiece and the cutting tool and so that a rotation angle of the relative rotation between the workpiece and the cutting tool during relative movement at a second speed is smaller than a rotation angle of the relative rotation during relative movement at a first speed in one repetitive movement. This configuration limits degradation of machining efficiency when the cutting tool machines the workpiece by performing one repetitive movement with respect to multiple relative rotations between the workpiece and the cutting tool.

In a machine tool and a control apparatus thereof, a repetitive movement unit is configured so that the cutting tool performs one repetitive movement with respect to multiple relative rotations between the workpiece and the cutting tool and so that a rotation angle of the relative rotation between the workpiece and the cutting tool during relative movement at a second speed is smaller than a rotation angle of the relative rotation during relative movement at a first speed in one repetitive movement. This configuration limits degradation of machining efficiency when the cutting tool machines the workpiece by performing one repetitive movement with respect to multiple relative rotations between the workpiece and the cutting tool.

A numerical controller controls a machine tool that performs a turning on a workpiece on the basis of a cycle instruction indicated by an NC program. The machine tool includes first and second cutter holders that are mutually coupled by a coupling member, and first and second tools are mounted on the cutter holders in mutually opposing fashion. The machine tool performs a turning according to a complex fixed cycle, in a reciprocal fashion rather than unidirectionally, using the first and second tools, and when the turning by the first tool has been completed and the first tool that has performed a turning is withdrawn, it is possible to perform a turning in the opposite direction by the second tool on the opposite side.

A control device includes a control part which generates a torque command based on a resultant command, which is obtained by adding a position deviation, which is the difference between a position command and the actual position of a feed shaft, to an oscillation command to control the feed shaft, and an elastic deformation amount calculation part which calculates the elastic deformation amount of a structure composed of a tool or workpiece and the feeding mechanism therefor based on the torque command. An oscillation command generation part generates the above oscillation command based on the rotation speed of the workpiece, the position command of the feed shaft, and the above elastic deformation amount.

A machine tool for machining a workpiece is provided with a cutting tool holder for holding a cutting tool and a rotation mechanism for holding the workpiece. One or both of the cutting tool holder and the rotation mechanism are movable on multiple axes so that the cutting tool is movable relative to the workpiece in multiple axial directions. A control device is provided for controlling the movement of one or both of the cutting tool holder and the rotation mechanism to synchronously vibrate the workpiece and the cutting tool relative to each other at a low frequency in multiple axial directions.

A machine tool control device according to one aspect of the present disclosure, which can prevent a workpiece from flying out, comprises: a total turning inertia estimation unit that, estimates the total turning inertia on the basis of feedback from a turning axis by causing the turning axis to rotate, said total turning inertia being the total inertia, around the turning axis, of the turning axis and an object that rotates together with the turning axis; a workpiece turning inertia estimation unit that estimates the workpiece turning inertia on the basis of the total turning inertia when a retention unit is not retaining a workpiece and the total turning inertia when the retention unit is retaining a workpiece, said workpiece turning inertia being the inertia, around the turning axis, of the workpiece; a maximum rotational speed calculation unit that, on the basis of the workpiece turning inertia, calculates the maximum rotational speed of the turning axis, at which the maximum energy when the workpiece separates from the retention unit is equal to a preset upper limit value; and a rotational speed limiting unit that limits the rotational speed of the turning axis so as not to exceed the maximum rotational speed.

A numerical control device includes: a memory storing in advance angular difference information between each of first cutting shafts formed for an upper tool post and a second cutting shaft of a lower tool post and a machining program including a movement command for the upper tool post to move an imaginary shaft, which moves along the same line as the second cutting shaft and performs cutting from a direction opposite to the second cutting shaft with respect to the main shaft; a shaft-command distribution processing unit distributing the movement command to move the imaginary shaft to the first cutting shaft components based on the angular difference information; and a shaft-synchronization processing unit driving the first cutting shafts based on the movement command distributed to the first cutting shaft components and driving the second cutting shaft by the movement amount same as that in the direction of the imaginary shaft.

To provide a controller for a machine tool that can shred shavings in a sure manner, even if a delay in notification occurs at the time of performing oscillation cutting. This controller of machine tools controls the machine tools that perform cutting working of a work by a cutting tool with a spindle and a feed axis operating cooperatively. The controller includes: an oscillation command calculating unit that calculates an oscillation command to cause relative oscillation of the cutting tool and the work, from a rotation speed of the spindle and a positional command of the cutting tool as to the work; a correction amount calculating unit that calculates a correction amount corresponding to an amount of delay notification to the oscillation command calculating unit regarding the rotation speed of the spindle; and a correction amount superimposing unit that superimposes the correction amount on the oscillation command.