To provide a controller for a machine tool capable of shredding chips and capable of performing machining by cutting correctly without implementation of a so-called finishing process. A controller for a machine tool includes: an oscillation command generation unit that generates an oscillation command for causing a work and a tool to oscillate relative to each other in a radial direction of the work based on a condition for oscillation; a movement command generation unit that generates a movement command for causing the work and the tool to move relative to each other for thread cutting of the work; an adder that adds the oscillation command and the movement command; and a determination unit that predetermines whether the oscillation command is to be added to the movement command, is which the adder outputs a superimposed command configured to include one or more types of machining patterns combining an arbitrary number of a total movement command with the oscillation command added, and an arbitrary number of a total movement command without the oscillation command added, in accordance with a result of determination by the determination unit.

A numerical control device according to an aspect of the present disclosure includes: a reference speed calculation unit configured to calculate a spindle speed which is a rotation number of the spindle in accordance with a machining program, and a feed speed which is a movement speed of the feed axis in accordance with the machining program; an oscillation command calculation unit configured to calculate an oscillation command, which is a periodic variation component superimposed on a command of the feed axis, based on the spindle speed and the feed speed, as well as an oscillation frequency magnification set in advance; a setting acquisition unit configured to acquire an upper limit value for frequency of the oscillation command; and an adjustment unit configured to adjust the frequency of the oscillation command, or adjust at least either of the spindle speed and the oscillation frequency magnification, so that the frequency of the oscillation command does not exceed the upper limit value.

A controller of a machine tool includes: a position command calculation unit which calculates a position command for relatively moving a workpiece and a tool; an oscillation operation execution determination unit which analyzes a machining program and which. determines whether or not an oscillation operation of relatively oscillating the workpiece and the tool is performed in a machining block; an oscillation operation intermittent execution determination unit which determines, when it is determined that the oscillation operation is performed, in the machining block, based on the state of the machine tool, whether the oscillation operation is enabled or disabled so as to determine whether or not the oscillation operation is intermittently performed; an oscillation command calculation unit which calculates, when it is determined that the oscillation operation is enabled, an oscillation command for relatively oscillating the workpiece and the tool; and an adder which adds the position command and the oscillation command together.

In a machine tool, under user set conditions, a cutting tool is fed in a feeding direction while the cutting tool is moved repetitively to cut a workpiece smoothly while separating chips easily. In the machine tool and a control apparatus thereof, control means is configured to set the number of rotations of relative rotation for executing machining of a workpiece, and the number of repetitions of repetitive movement during one rotation of the relative rotation in accordance with a repetitive movement frequency attributable to a cycle during which an operation instruction can be issued.

The invention provides a control apparatus for a machine tool, which can perform reciprocating vibration in consideration of a vibration frequency, increase flexibility in machining a workpiece, and perform vibration cutting by means of an external spindle or the like without rotating a spindle. The control apparatus and the machine tool include control means. The control means includes an imaginary spindle regarded as a spindle for rotating a workpiece W or a cutting tool. The control means sets the number of rotations of the imaginary spindle and the number of reciprocating vibrations in accordance with a vibration frequency attributable to a cycle during which an operation instruction can be issued.

A numerical controller includes a position instruction generating unit configured to generate the position instruction; an oscillation instruction generating unit configured to generate the oscillation instruction; a position speed control unit configured to add the position instruction and the oscillation instruction to generate a synthesized instruction; and a current control unit configured to control movement of a tool or rotation of a spindle. The oscillation instruction generating unit includes a tracking error calculating unit configured to obtain and calculate an actual angle and an ideal angle of the spindle, and a frequency recalculating unit configured to recalculate the oscillation frequency or a rotational speed of the spindle based on the actual angle and the ideal angle. The current control unit controls the movement of the tool or the rotation of the spindle according to the recalculated oscillation frequency or rotational speed of the spindle.

A numerical control apparatus includes: a drive unit controlling a main shaft rotating a workpiece, a first drive shaft feeding a cutting tool relatively to the workpiece along a perpendicular direction to a lead direction of a thread, and a second drive shaft feeding the cutting tool relatively to the workpiece along the lead direction; and a vibration unit superimposing, on movement of the first drive shaft, vibration having a period having a predetermined ratio with a rotation period of the main shaft, and forms a thread on the workpiece by moving the cutting tool and the workpiece relative to each other and performing cut processes on the workpiece. The numerical control apparatus includes a thread-cutting vibration adjustment unit controlling the drive unit to shift phase of the vibration with respect to phase of the main shaft by a predetermined vibration phase shift amount every time in the cut processes.

A control apparatus for machine tool, in accordance with user set conditions, feeds a cutting tool in a feeding direction while reciprocatively vibrating the cutting tool, smoothly cuts a workpiece, and achieves a machined surface having an improved appearance. In a machine tool and a control apparatus thereof, a control means is configured to set the number of rotations of relative rotation and the number of vibrations of reciprocating vibration during one rotation of the relative rotation in accordance with a vibration frequency attributable to a cycle during which an operation instruction can be issued, and the control means includes adjusting means configured to adjust the number of rotations or the number of vibrations set by the control means.

A control device for a machine tool and a machine tool, for which settings of the number of vibrations per rotation become easy, is provided. The control device of the machine tool controls a relative rotation between a workpiece and a cutting tool and a relative reciprocal movement between the workpiece and the cutting tool in a feed direction to perform vibration cutting to the workpiece. The control device includes a control section for controlling a spindle headstock, a first tool post, and a second tool post, the workpiece W being installed on the spindle headstock, the first tool post being provided to be reciprocally movable along the feed direction with respect to the spindle headstock and installed with a first cutting tool for cutting the workpiece, and the second tool post being provided to be reciprocally movable along the feed direction with respect to the spindle headstock independently of the first tool post and installed with a second cutting tool for cutting the workpiece.

To provide a controller for a machine tool capable of shredding chips in any thread cutting method. A controller for a machine tool comprises: an oscillation condition calculation unit that calculates an oscillation amplitude and an oscillation direction allowing shredding of chips occurring from lathe-turning machining based on an infeed amount in a radial direction of a work and a shift amount in a circumferential direction of the work relative to a last machining path of a tool used for the lathe-turning machining on the work; an oscillation command calculation unit that calculates an oscillation command for causing the work and the tool to oscillate relative to each other based on the oscillation amplitude and the oscillation direction calculated by the oscillation condition calculation unit; and an adder that adds a movement command for moving the work and the tool relative to each other for the lathe-turning machining on the work and the oscillation command.