In the high-efficiency machining of blade parts according to the present invention, there is no reversal of the operating direction of a rotating shaft, and a high-quality machined surface can be obtained rapidly. A machining program is created for a workpiece such that: when a part having a convex curved surface and a concave curved surface, with a pair of edge portions as a boundary, is removal-machined, a virtual convex curve, the curvature of which is not inverted with respect to the convex curved surface, with the curves of the pair of edges as the tangent line, is set for the concave curved surface; a drive surface, for defining tool orientation without curvature inversion, is created by using the virtual convex curve, the convex curve set on the convex curved surface, and the convex curves set on the pair of edges; and a tool axis direction during removal machining is set on the basis of the normal direction of the drive surface for tool orientation definition.

In the high-efficiency machining of blade parts according to the present invention, there is no reversal of the operating direction of a rotating shaft, and a high-quality machined surface can be obtained rapidly. A machining program is created for a workpiece such that: when a part having a convex curved surface and a concave curved surface, with a pair of edge portions as a boundary, is removal-machined, a virtual convex curve, the curvature of which is not inverted with respect to the convex curved surface, with the curves of the pair of edges as the tangent line, is set for the concave curved surface; a drive surface, for defining tool orientation without curvature inversion, is created by using the virtual convex curve, the convex curve set on the convex curved surface, and the convex curves set on the pair of edges; and a tool axis direction during removal machining is set on the basis of the normal direction of the drive surface for tool orientation definition.

A machining device threads a workpiece by relatively rotating the workpiece and a multi-blade tool and relatively moving them along a feed direction to perform cutting processes in the radial direction of the workpiece along the same cutting path in a predetermined spiral form. A controller performs a groove machining to form a threaded portion with vibration in the radial direction of the workpiece and a finish machining to form the threaded portion by bringing the multi-blade tool into contact with the grooved portion of the workpiece. The multi-blade tool has a first cutting blade and a second cutting blade arranged side by side along the feed direction. The controller sets amplitude of a vibration waveform to a value at which a cutting edge of the second cutting blade does not come into contact with the screw bottom surface of the workpiece in the finish machining.

A machining device threads a workpiece by relatively rotating the workpiece and a multi-blade tool and relatively moving them along a feed direction to perform cutting processes in the radial direction of the workpiece along the same cutting path in a predetermined spiral form. A controller performs a groove machining to form a threaded portion with vibration in the radial direction of the workpiece and a finish machining to form the threaded portion by bringing the multi-blade tool into contact with the grooved portion of the workpiece. The multi-blade tool has a first cutting blade and a second cutting blade arranged side by side along the feed direction. The controller sets amplitude of a vibration waveform to a value at which a cutting edge of the second cutting blade does not come into contact with the screw bottom surface of the workpiece in the finish machining.

The objective of the present invention is to provide a machine tool control device with which chips can be reliably divided and discharged, and with which damage to a tool can be suppressed by reducing shock when the tool cuts into a workpiece. A machine tool control device 100 which controls a main axis that causes a tool T to rotate relative to a workpiece W, and which executes a cutting process by controlling a feed axis to move the tool T and the workpiece W while causing the same to oscillate relative to one another in a feed direction, is provided with an oscillation command generating unit 16 which generates an oscillation command on the basis of a predetermined oscillation condition, and a position and speed control unit 15 which controls a motor 30 that drives the feed axis, on the basis of a superimposed command generated by superimposing the oscillation command generated by the oscillation command generating unit 16 onto a position command or a position deviation, wherein the oscillation command generating unit 16 changes at least one of an oscillation command phase progression method and an oscillation command amplitude, on the basis of either an oscillation phase calculated on the basis of the predetermined oscillation condition, or time.

The objective of the present invention is to provide a machine tool control device with which chips can be reliably divided and discharged, and with which damage to a tool can be suppressed by reducing shock when the tool cuts into a workpiece. A machine tool control device 100 which controls a main axis that causes a tool T to rotate relative to a workpiece W, and which executes a cutting process by controlling a feed axis to move the tool T and the workpiece W while causing the same to oscillate relative to one another in a feed direction, is provided with an oscillation command generating unit 16 which generates an oscillation command on the basis of a predetermined oscillation condition, and a position and speed control unit 15 which controls a motor 30 that drives the feed axis, on the basis of a superimposed command generated by superimposing the oscillation command generated by the oscillation command generating unit 16 onto a position command or a position deviation, wherein the oscillation command generating unit 16 changes at least one of an oscillation command phase progression method and an oscillation command amplitude, on the basis of either an oscillation phase calculated on the basis of the predetermined oscillation condition, or time.

A thermal displacement compensation apparatus includes a temperature measuring unit, a thermal displacement estimating unit, a thermal displacement compensation unit, a displacement measuring unit, a data recording unit, a thermal displacement compensation learning unit, and a displacement measurement timing diagnostic unit. The displacement measuring unit measures a displacement of a machine tool after compensating an axis command value. The thermal displacement compensation learning unit determines a thermal displacement estimation formula based on temperature information and the displacement recorded in the data recording unit. The displacement measurement timing diagnostic unit compares the temperature information at a past displacement measurement recorded in the data recording unit with current temperature information obtained from the temperature measuring unit, and determines whether to measure the displacement by the displacement measuring unit or not at a predetermined diagnosis timing.

A thermal displacement compensation apparatus includes a temperature measuring unit, a thermal displacement estimating unit, a thermal displacement compensation unit, a displacement measuring unit, a data recording unit, a thermal displacement compensation learning unit, and a displacement measurement timing diagnostic unit. The displacement measuring unit measures a displacement of a machine tool after compensating an axis command value. The thermal displacement compensation learning unit determines a thermal displacement estimation formula based on temperature information and the displacement recorded in the data recording unit. The displacement measurement timing diagnostic unit compares the temperature information at a past displacement measurement recorded in the data recording unit with current temperature information obtained from the temperature measuring unit, and determines whether to measure the displacement by the displacement measuring unit or not at a predetermined diagnosis timing.

A method of machining a workpiece using a machine tool, the machine tool comprising a tool mount carrying a tool, a workpiece mount carrying a workpiece, a drive mechanism for moving at least one of the tool mount and the workpiece mount relative to the other, and a control arrangement for controlling the drive mechanism. The method comprises moving at least one of the tool mount and the workpiece mount with the drive mechanism under the control of the control arrangement so that the tool contacts a portion of the workpiece to commence a machining operation, and the tool then removes material from the portion of the workpiece until completion of the machining operation, the movement being such that the relative velocity between the tool and the workpiece decreases continuously during the majority of the time that the tool and the workpiece are in contact with each other during the machining operation.

A numerical value controller includes: a storage unit storing a machining program involving executing canned cycles including a first operation for moving a tool to a return point, a second operation for positioning a drilling position of a workpiece relative to the tool, a third operation for moving the tool from the return point to a hole bottom point, and a fourth operation for moving the tool from the hole bottom point to a terminal point located toward the hole bottom point relative to the return point; a control unit controls relative movement between the tool and the workpiece based on the machining program and moves the tool along curved paths by starting the second operation before the first operation ends and by starting the third operation before the second operation ends; and a distance calculating unit calculates a retraction distance from the workpiece to the return point.