Numerical control device for controlling machine tool using rotary multi-edge tool

1 . A numerical control device for controlling a machine tool based on a machining program, the machine tool being configured to machine a workpiece using a rotary multi-edge tool having a plurality of cutting edges, the numerical control device comprising:

a processor configured to control the numerical control device to:

acquire tool data including a number of the cutting edges of the rotary multi-edge tool;

acquire machining information including a feed direction, a feed speed, and a number of rotations for the rotary multi-edge tool to move with respect to the workpiece in accordance with the machining program;

acquire an oscillation condition for the rotary multi-edge tool to oscillate in at least one of the feed direction or a direction orthogonal to the feed direction;

calculate a movement command for the rotary multi-edge tool to perform a relative movement with respect to the workpiece, the relative movement being coincident with a composite motion resulting from superposition of a basic movement in the feed direction at the feed speed and an oscillation determined based on the tool data, the number of rotations, and the oscillation condition; and

control the multi-edge tool to perform the relative movement coincident with the composite motion based on the movement command to machine the workpiece,

wherein the oscillation causes the rotary multi-edge tool to oscillate in the feed direction and a direction orthogonal to the feed direction,

a number of the cutting edges that pass through an identical rotation position in one cycle of the oscillation is defined as N, and

the numerical control device maintains a peak of protrusion of the rotary multi-edge tool in a rotation axis direction at a maximum value for a period equal to or longer than 1/N of the one cycle during the oscillation.

2 . A method for machining a workpiece using a rotary multi-edge tool having a plurality of cutting edges, the method comprising:

acquiring tool data regarding the rotary multi-edge tool;

acquiring machining information including a feed direction, a feed speed, and a number of rotations for the rotary multi-edge tool to move with respect to the workpiece;

acquiring an oscillation condition for the rotary multi-edge tool to oscillate in at least one of the feed direction or a direction orthogonal to the feed direction;

calculating a composite motion by superposing a basic movement in the feed direction at the feed speed and an oscillation determined based on the tool data, the number of rotations, and the oscillation condition; and

causing the rotary multi-edge tool to perform a relative movement with respect to the workpiece, the relative movement being coincident with the composite motion,

wherein the oscillation causes the rotary multi-edge tool to oscillate in the feed direction and a direction orthogonal to the feed direction,

a number of the cutting edges that pass through an identical rotation position in one cycle of the oscillation is defined as N, and

the method maintains a peak of protrusion of the rotary multi-edge tool in a rotation axis direction at a maximum value for a period equal to or longer than 1/N of the one cycle during the oscillation.

3 . A numerical control device for controlling a machine tool based on a machining program, the machine tool being configured to machine a workpiece using a rotary multi-edge tool having a plurality of cutting edges, the numerical control device comprising:

a processor configured to control the numerical control device to:

acquire tool data including a number of the cutting edges of the rotary multi-edge tool;

acquire machining information including a feed direction, a feed speed, and a number of rotations for the rotary multi-edge tool to move with respect to the workpiece in accordance with the machining program;

acquire an oscillation condition for the rotary multi-edge tool to oscillate in at least one of the feed direction or a direction orthogonal to the feed direction;

calculate a movement command for the rotary multi-edge tool to perform a relative movement with respect to the workpiece, the relative movement being coincident with a composite motion resulting from superposition of a basic movement in the feed direction at the feed speed and an oscillation determined based on the tool data, the number of rotations, and the oscillation condition; and

control the multi-edge tool to perform the relative movement coincident with the composite motion based on the movement command to machine the workpiece,

wherein the oscillation causes the rotary multi-edge tool to oscillate in the feed direction and a direction orthogonal to the feed direction, and

the processor is configured to determine the oscillation such that a protrusion amount of the rotary multi-edge tool in a rotation axis direction is maximized at a position where a retraction amount of the rotary multi-edge tool in the feed direction reaches a maximum.

4 . A numerical control device for controlling a machine tool based on a machining program, the machine tool being configured to machine a workpiece using a rotary multi-edge tool having a plurality of cutting edges, the numerical control device comprising:

a processor configured to control the numerical control device to:

acquire tool data including a number of the cutting edges of the rotary multi-edge tool;

acquire machining information including a feed direction, a feed speed, and a number of rotations for the rotary multi-edge tool to move with respect to the workpiece in accordance with the machining program;

acquire an oscillation condition for the rotary multi-edge tool to oscillate in at least one of the feed direction or a direction orthogonal to the feed direction;

calculate a movement command for the rotary multi-edge tool to perform a relative movement with respect to the workpiece, the relative movement being coincident with a composite motion resulting from superposition of a basic movement in the feed direction at the feed speed and an oscillation determined based on the tool data, the number of rotations, and the oscillation condition; and

control the multi-edge tool to perform the relative movement coincident with the composite motion based on the movement command to machine the workpiece,

wherein the processor is configured to check a rotation position of the rotary multi-edge tool, and

determine the oscillation such that a specific one of the cutting edges is positioned at a forwardmost point in the feed direction at a predetermined phase of the oscillation.

5 . The numerical control device according to claim 4 , wherein

the processor is configured to select, from the cutting edges, one cutting edge that is positioned at the forwardmost point in the feed direction at a predetermined phase of the oscillation.

6 . A method for machining a workpiece using a rotary multi-edge tool having a plurality of cutting edges, the method comprising:

acquiring tool data regarding the rotary multi-edge tool;

acquiring machining information including a feed direction, a feed speed, and a number of rotations for the rotary multi-edge tool to move with respect to the workpiece;

acquiring an oscillation condition for the rotary multi-edge tool to oscillate in at least one of the feed direction or a direction orthogonal to the feed direction;

calculating a composite motion by superposing a basic movement in the feed direction at the feed speed and an oscillation determined based on the tool data, the number of rotations, and the oscillation condition; and

causing the rotary multi-edge tool to perform a relative movement with respect to the workpiece, the relative movement being coincident with the composite motion,

wherein the oscillation causes the rotary multi-edge tool to oscillate in the feed direction and a direction orthogonal to the feed direction, and

the method includes determining the oscillation such that a protrusion amount of the rotary multi-edge tool in a rotation axis direction is maximized at a position where a retraction amount of the rotary multi-edge tool in the feed direction reaches a maximum.

7 . A method for machining a workpiece using a rotary multi-edge tool having a plurality of cutting edges, the method comprising:

acquiring tool data regarding the rotary multi-edge tool;

acquiring machining information including a feed direction, a feed speed, and a number of rotations for the rotary multi-edge tool to move with respect to the workpiece;

acquiring an oscillation condition for the rotary multi-edge tool to oscillate in at least one of the feed direction or a direction orthogonal to the feed direction;

calculating a composite motion by superposing a basic movement in the feed direction at the feed speed and an oscillation determined based on the tool data, the number of rotations, and the oscillation condition;

causing the rotary multi-edge tool to perform a relative movement with respect to the workpiece, the relative movement being coincident with the composite motion;

checking a rotation position of the rotary multi-edge tool; and

determining the oscillation such that a specific one of the cutting edges is positioned at a forwardmost point in the feed direction at a predetermined phase of the oscillation.