A machine forms threads on a workpiece by relatively feeding the workpiece and a cutting tool in a feeding direction while relatively rotating the workpiece and the cutting tool, and by performing a helical cutting work multiple times while carrying out relative reciprocal vibration of the workpiece and the cutting tool in a radial direction of the workpiece. The machine tool or a control device of the machine tool includes a vibration setting unit to set a pattern of vibration during each cutting work accompanied by the reciprocal vibration so that a cut portion of one cutting work partially includes a portion that has been cut in another cutting work. The machine tool and the control device prevent a long, continuous chip from becoming entangled with a workpiece or a cutting tool in the process of forming threads on the workpiece.

To provide a control device for a machine tool capable of performing thread cutting while reducing the load on the machine tool from the oscillating operation, without extending the cycle time, and capable of reliably shredding chips in a case of performing the non-oscillating operation in the present pass after the oscillating operation in the previous pass. A control device for a machine tool includes: an oscillating operation execution determination unit that determines whether to execute an oscillating operation that causes the cutting tool to oscillate in the radial direction of the workpiece; an oscillation command generation unit that generates an oscillation command of the oscillating operation based on a determination result; a control unit that superimposes the oscillation command on a position command of the feed axis to generate a drive command. The oscillating operation execution determination unit determines to intermittently execute the oscillating operation, and the oscillation command generation unit generates an oscillation command so that a non-oscillating cutting portion of a present pass includes a portion at which oscillating cutting was performed in a previous pass, or so that an oscillating cutting portion of the present pass includes a portion at which non-oscillating cutting was performed in the previous pass.

To provide a control device for a machine tool capable of performing thread cutting while reducing the load on the machine tool from the oscillating operation, without extending the cycle time, and capable of reliably shredding chips in a case of performing the non-oscillating operation in the present pass after the oscillating operation in the previous pass. A control device for a machine tool includes: an oscillating operation execution determination unit that determines whether to execute an oscillating operation that causes the cutting tool to oscillate in the radial direction of the workpiece; an oscillation command generation unit that generates an oscillation command of the oscillating operation based on a determination result; a control unit that superimposes the oscillation command on a position command of the feed axis to generate a drive command. The oscillating operation execution determination unit determines to intermittently execute the oscillating operation, and the oscillation command generation unit generates an oscillation command so that a non-oscillating cutting portion of a present pass includes a portion at which oscillating cutting was performed in a previous pass, or so that an oscillating cutting portion of the present pass includes a portion at which non-oscillating cutting was performed in the previous pass.

To provide a control device for a machine tool capable of performing thread cutting while reducing the load on the machine tool from the oscillating operation, without extending the cycle time, and capable of reliably shredding chips in a case of performing the non-oscillating operation in the present pass after the oscillating operation in the previous pass. A control device for a machine tool includes: an oscillating operation execution determination unit that determines whether to execute an oscillating operation that causes the cutting tool to oscillate in the radial direction of the workpiece; an oscillation command generation unit that generates an oscillation command of the oscillating operation based on a determination result; a control unit that superimposes the oscillation command on a position command of the feed axis to generate a drive command. The oscillating operation execution determination unit determines to intermittently execute the oscillating operation, and the oscillation command generation unit generates an oscillation command so that a non-oscillating cutting portion of a present pass includes a portion at which oscillating cutting was performed in a previous pass, or so that an oscillating cutting portion of the present pass includes a portion at which non-oscillating cutting was performed in the previous pass.

To provide a control device for a machine tool capable of performing thread cutting while reducing the load on the machine tool from the oscillating operation, without extending the cycle time, and capable of reliably shredding chips in a case of performing the non-oscillating operation in the present pass after the oscillating operation in the previous pass. A control device for a machine tool includes: an oscillating operation execution determination unit that determines whether to execute an oscillating operation that causes the cutting tool to oscillate in the radial direction of the workpiece; an oscillation command generation unit that generates an oscillation command of the oscillating operation based on a determination result; a control unit that superimposes the oscillation command on a position command of the feed axis to generate a drive command. The oscillating operation execution determination unit determines to intermittently execute the oscillating operation, and the oscillation command generation unit generates an oscillation command so that a non-oscillating cutting portion of a present pass includes a portion at which oscillating cutting was performed in a previous pass, or so that an oscillating cutting portion of the present pass includes a portion at which non-oscillating cutting was performed in the previous pass.

A machine tool and a control device for the machine tool for shortening the machining time of a workpiece in a case where the relative and reciprocal vibration of workpiece holder and tool post in the radial direction of the workpiece is stopped during a period from an initial point until when the workpiece and the cutting tool come into contact with each other is provided. In the machine tool, when threading the workpiece to form a threaded portion on the workpiece by relatively moving the workpiece and the cutting tool in the feed direction while relatively rotating the workpiece and the cutting tool 130 to perform multiple times of cutting processes along the same cutting path in a predetermined spiral form, the cutting tool is brought closer toward the workpiece in the feed direction from a predetermined initial point at which the workpiece and the cutting tool are separated from each other, the workpiece and the cutting tool come into contact with each other, and the threading is started with the contact. During the period from the initial point until when the workpiece and the cutting tool come into contact with each other, a controller stops the vibration of the cutting tool, and, in continuous cutting processes in the multiple times of cutting processes in the threading, the control means sets a phase position of the tool post in the vibration direction and stops the reciprocal vibration so that, when the workpiece and the cutting tool come into contact with each other, each of the continuous cutting processes has a predetermined phase in the reciprocal vibration relative to a rotation phase of the workpiece at the start of the threading.

To provide a control device for a machine tool capable of performing thread cutting while reducing the load on the machine tool from the oscillating operation, without extending the cycle time, and capable of reliably shredding chips in a case of performing the non-oscillating operation in the present pass after the oscillating operation in the previous pass. A control device for a machine tool includes: an oscillating operation execution determination unit that determines whether to execute an oscillating operation that causes the cutting tool to oscillate in the radial direction of the workpiece; an oscillation command generation unit that generates an oscillation command of the oscillating operation based on a determination result; a control unit that superimposes the oscillation command on a position command of the feed axis to generate a drive command. The oscillating operation execution determination unit determines to intermittently execute the oscillating operation, and the oscillation command generation unit generates an oscillation command so that a non-oscillating cutting portion of a present pass includes a portion at which oscillating cutting was performed in a previous pass, or so that an oscillating cutting portion of the present pass includes a portion at which non-oscillating cutting was performed in the previous pass.

To provide a control device for a machine tool capable of performing thread cutting while reducing the load on the machine tool from the oscillating operation, without extending the cycle time, and capable of reliably shredding chips in a case of performing the non-oscillating operation in the present pass after the oscillating operation in the previous pass. A control device for a machine tool includes: an oscillating operation execution determination unit that determines whether to execute an oscillating operation that causes the cutting tool to oscillate in the radial direction of the workpiece; an oscillation command generation unit that generates an oscillation command of the oscillating operation based on a determination result; a control unit that superimposes the oscillation command on a position command of the feed axis to generate a drive command. The oscillating operation execution determination unit determines to intermittently execute the oscillating operation, and the oscillation command generation unit generates an oscillation command so that a non-oscillating cutting portion of a present pass includes a portion at which oscillating cutting was performed in a previous pass, or so that an oscillating cutting portion of the present pass includes a portion at which non-oscillating cutting was performed in the previous pass.

A method for cutting a thread on a rotating workpiece by means of a cutting tool having a cutting edge. The method includes sequentially performing a number of passes, each pass includes simultaneously moving the cutting tool and/or the workpiece relative to each other along and oscillating the cutting tool towards and away from workpiece rotational such that the cutting edge exits and enters the workpiece forming an air cut. The air cuts performed in a final pass are longer than all the other passes.

A method for cutting a thread on a rotating workpiece by means of a cutting tool having a cutting edge. The method includes sequentially performing a number of passes, each pass includes simultaneously moving the cutting tool and/or the workpiece relative to each other along and oscillating the cutting tool towards and away from workpiece rotational such that the cutting edge exits and enters the workpiece forming an air cut. The air cuts performed in a final pass are longer than all the other passes.