JP2022018261A - Cutting tool and cutting method - Google Patents

Abstract

To provide a cutting tool and a cutting method, which can stably suppress chattering vibration.SOLUTION: A cutting tool includes: a rake face 11; a flank 12; a cutting edge 13 formed on a ridge line for connecting the rake face 11 and the flank 12; and a projection 14 which projects from the flank 12 and is arranged away from the cutting edge 13. A virtual plane including an edge length direction in which the cutting edge 13 extends and a prescribed direction crossing the cutting edge 13 is defined as a machining reference surface VS. A direction orthogonal to the machining reference surface VS is defined as a first direction D1, the prescribed direction is defined as D2, and a direction orthogonal to the first direction D1 and the second direction D2 is defined as a third direction D3. The flank 12 is inclined toward the inside in the first direction D1 as the flank extends from the cutting edge 13 toward a rear side in the second direction D2. A plurality of projections 14 are provided on the flank 12.SELECTED DRAWING: Figure 5

Description

The present invention relates to a cutting tool and a cutting method capable of stably suppressing chatter vibration.

The chatter vibration generated during cutting affects the machined surface accuracy of the work material. For example, Non-Patent Document 1 below describes the use of a process damping phenomenon as a technique for suppressing chatter vibration. Process damping is a phenomenon in which, when chatter vibration occurs during cutting, the flank of the cutting tool comes into contact with the machined surface of the work material, causing a vibration damping effect.

Hidenori Igita, Norikazu Suzuki, Eiji Shamoto, "Proposal of flank texture to suppress chatter vibration in cutting", Proceedings of the 2017 Spring Meeting of the Japan Society for Precision Engineering, 2017, pp. 989-990

This type of cutting tool is required to suppress chatter vibration in a wide frequency band under various cutting conditions.

One of the objects of the present invention is to provide a cutting tool and a cutting method capable of stably suppressing chatter vibration.

One aspect of the cutting tool of the present invention is a rake face, a flank, a cutting edge formed on a ridge connecting the rake face and the flank, and a cutting edge that protrudes from the flank and separates from the cutting edge. A virtual plane having a convex portion to be arranged and including a blade length direction in which the cutting edge extends and a predetermined direction intersecting the cutting edge is set as a machining reference plane, and a direction orthogonal to the machining reference plane is set as a first direction. The predetermined direction is the second direction, the first direction and the direction orthogonal to the second direction are the third direction, and of the first directions, the direction from the cutting edge to the inside of the tool is the inside of the first direction. Of the second direction, the direction from the cutting edge to the convex portion is the rear side in the second direction, and the flank is the first direction as it goes from the cutting edge to the rear side in the second direction. It is inclined inward, and a plurality of the convex portions are provided on the flank.

According to the present invention, since the convex portion protruding from the flank is provided, a phenomenon called process damping occurs during cutting such as low cutting speed conditions, and chatter vibration is suppressed. Process damping is a phenomenon in which, when chatter vibration occurs during cutting, the flank of the cutting tool comes into contact with the machined surface of the work material, causing a vibration damping effect. That is, in the present invention, by providing the convex portion on the flank, the convex portion easily comes into contact with the machined surface of the work material, so that the process damping phenomenon can be positively exhibited and chatter vibration can be suppressed.

In the present invention, since a plurality of convex portions are provided on the flank, the distance and shape of each convex portion from the cutting edge, the amount of protrusion from the flank, the length in the second direction, and the length or blade in the third direction. By appropriately setting the length in the long direction and the like, the vibration wavelength region in which the process damping effect is exhibited can be made different for each convex portion, and thereby the frequency range in which chatter vibration can be suppressed can be expanded. Therefore, it is possible to suppress chatter vibration in a wide frequency band. Therefore, according to the present invention, chatter vibration can be stably suppressed.

In the present invention, the "predetermined direction" (second direction) is an apparent direction in which the machined surface of the work material and the cutting edge are relatively moved without vibration during cutting, that is, "cutting". Refers to "direction".
Further, the "machining reference plane" may be rephrased as a virtual plane including a ridgeline of the cutting edge and a virtual straight line intersecting the ridgeline and extending in a predetermined direction (cutting direction).

In the cutting tool, the plurality of convex portions may have a first convex portion and a second convex portion located on the rear side of the first convex portion in the second direction.

In this case, the plurality of convex portions include a first convex portion and a second convex portion having different distances from the cutting edge in the second direction. Therefore, the frequency range in which the first convex portion exhibits the process damping effect and the frequency range in which the second convex portion exhibits the process damping effect can be made different from each other, and the process can be robustly performed in a wide frequency band. A damping effect can be exhibited.

In the cutting tool, the amount of protrusion of the second convex portion from the flank surface may be larger than the amount of protrusion of the first convex portion from the flank surface.

In this case, the distance in the first direction between the machined surface of the work material (corresponding to the machining reference surface) and the first convex portion, and the first direction between the machined surface of the work material and the second convex portion. The difference from the distance can be reduced, or each distance can be made the same. As a result, when chatter vibration occurs during cutting, each convex portion can be stably brought into contact with the machined surface. The process damping phenomenon is stably expressed, and chatter vibration is stably suppressed.

In the cutting tool, a plurality of the first convex portions are provided at intervals in the blade length direction, and a plurality of the second convex portions are provided at intervals in the blade length direction. The convex portion and the second convex portion may be arranged alternately in the blade length direction.

In this case, since a plurality of first convex portions are arranged at intervals in the blade length direction of the cutting edge, welding may occur between the cutting edge and the first convex portion, or the cutting edge may be damaged by welding. Can be suppressed. Further, since the first convex portion and the second convex portion are alternately arranged in the blade length direction, the region where the convex portion is not arranged can be kept small in the blade length direction. In other words, in the blade length direction, the process damping effect due to the convex portion is exhibited in a wide range, and the chatter vibration is suppressed more stably.

In the cutting tool, the first convex portion may extend in the blade length direction, and the second convex portion may extend in the blade length direction.

In this case, the process damping effect of each convex portion can be exhibited in a wide range in the blade length direction.

In the cutting tool, the plurality of the convex portions have a plurality of first convex portions arranged at intervals in the blade length direction, and each of the first convex portions extends in the second direction. May be.

In this case, since a plurality of first convex portions are arranged at intervals in the blade length direction of the cutting edge, welding may occur between the cutting edge and the first convex portion, or the cutting edge may be damaged by welding. Can be suppressed. Further, since the first convex portion extends in the second direction, the first convex portion can expand the vibration wavelength region in which the process damping effect is exhibited, and the chatter vibration is stably suppressed.

In the cutting tool, the plurality of the convex portions have a plurality of first convex portions arranged at intervals in the blade length direction, and each of the first convex portions has the blade length direction and the first convex portion. It may extend in the direction in which the two directions are combined.

In this case, since a plurality of first convex portions are arranged at intervals in the blade length direction of the cutting edge, welding may occur between the cutting edge and the first convex portion, or the cutting edge may be damaged by welding. Can be suppressed. Further, since the first convex portion extends at least in the second direction, the vibration wavelength region in which the first convex portion exhibits the process damping effect can be expanded. Specifically, the first convex portion has a blade length. Since the direction and the second direction are combined, the process damping effect of the first convex portion can be exhibited in a wide range in the blade length direction.

In the cutting tool, the direction from the cutting edge to the outside of the tool in the first direction is the outside of the first direction, and the direction from the convex portion to the cutting edge in the second direction is the front side in the second direction. As such, the convex portion has a top surface facing outward in the first direction and a front surface facing the front side in the second direction and connecting the top surface and the flank, and the top surface is said to be said. The amount of protrusion from the flank may increase toward the rear side in the second direction.

In this case, the top surface of each convex portion has a larger amount of protrusion from the flank toward the rear side in the second direction, that is, the top surface is inclined with respect to the flank. Therefore, in a cross-sectional view perpendicular to the third direction, the inclination of the top surface of the convex portion with respect to the machined surface (the relief of the top surface) is larger than the clearance angle of the clearance surface with respect to the machined surface (corresponding to the machining reference surface) of the work material. The angle corresponding to the angle) can be reduced, and when chatter vibration occurs during cutting, this top surface can be stably brought into contact with the machined surface. As a result, the process damping phenomenon is stably expressed, and chatter vibration is stably suppressed.

Further, one aspect of the present invention is a cutting method in which a machined surface of a work material is cut by a cutting tool, in which the cutting tool connects a rake surface, a flank surface, and the rake face and the flank surface. It comprises a cutting edge formed on a ridge and a convex portion protruding from the flank and disposed away from the cutting edge, including a blade length direction in which the cutting edge extends and a cutting direction intersecting the cutting edge. The virtual plane is used as a machining reference plane, the direction orthogonal to the machining reference plane is set as the first direction, the cutting direction is set as the second direction, and the first direction and the direction orthogonal to the second direction are set as the third direction. Of the first direction, the direction from the cutting edge to the inside of the tool is the inside of the first direction, and the direction from the cutting edge to the convex portion of the second direction is the rear side of the second direction. The surface is inclined inward in the first direction from the cutting edge toward the rear side in the second direction, and a plurality of convex portions are provided on the flank and a cross section perpendicular to the third direction. Visually, the clearance angle formed between the flank and the machining reference plane is γn, the maximum wear width of the flank along the second direction is VBmax, and the machining reference in the first direction. The distance H between the surface and each of the convex portions is VBmax · tanγn or more.

According to the cutting method of the present invention, the distance H between the machining reference surface (corresponding to the machined surface of the work material) and each convex portion, that is, the distance of each convex portion with respect to the machined surface of the work material. H is VBmax · tanγn or more. Therefore, chatter vibration can be stably suppressed by the plurality of convex portions until the flank wear of the cutting tool becomes maximum and the tool life is reached.

Further, one aspect of the present invention is a cutting tool that is rotated in the circumferential direction around the tool axis, and among the circumferential directions, a rake face, a flank surface, a rake face, and the flank facing the tool rotation direction. A cutting edge formed on a ridge line connecting the surfaces and a convex portion protruding from the flank and arranged away from the cutting edge are provided, and the flank is opposed to the cutting edge in the circumferential direction. In the direction of tool rotation, the tool axis is inclined inward in the radial direction orthogonal to the tool axis, or inclined toward the base end side in the axial direction in which the tool axis extends, and the convex portion is said. Multiple are provided on the flank.

According to the present invention, since the convex portion protruding from the flank is provided, a process damping phenomenon occurs during cutting (rolling) such as low cutting speed conditions, and chatter vibration is suppressed. That is, in the present invention, by providing the convex portion on the flank, the convex portion easily comes into contact with the machined surface of the work material, so that the process damping phenomenon can be positively exhibited and chatter vibration can be suppressed.

Further, in the present invention, since a plurality of convex portions are provided on the flank, the distance from the cutting edge of each convex portion, the shape, the amount of protrusion from the flank, the length in the circumferential direction, the length in the axial direction, and the radial direction. By appropriately setting the length or the length in the blade length direction, the vibration wavelength region in which the process damping effect is exhibited can be made different for each convex portion, and as a result, the frequency range in which chatter vibration can be suppressed can be set. Can be expanded. Therefore, it is possible to suppress chatter vibration in a wide frequency band. Therefore, according to the present invention, chatter vibration can be stably suppressed.

In the present invention, in the "circumferential direction" around the tool axis, that is, the "circumferential direction" centered on the tool axis, the machined surface of the work material and the cutting edge are relatively moved without vibration during cutting. It is the apparent direction to be seen, that is, the "cutting direction".

In the cutting tool, the plurality of the convex portions may have a first convex portion and a second convex portion located in the anti-tool rotation direction with respect to the first convex portion.

In this case, the plurality of convex portions include a first convex portion and a second convex portion having different distances from the cutting edge in the circumferential direction. Therefore, the frequency range in which the first convex portion exhibits the process damping effect and the frequency range in which the second convex portion exhibits the process damping effect can be made different from each other, and the process can be robustly performed in a wide frequency band. A damping effect can be exhibited.

In the cutting tool, the amount of protrusion of the second convex portion from the flank surface may be larger than the amount of protrusion of the first convex portion from the flank surface.

In this case, the difference between the distance between the machined surface of the work material and the first convex portion and the distance between the machined surface of the work material and the second convex portion may be reduced, or the distances may be the same. can do. As a result, when chatter vibration occurs during cutting, each convex portion can be stably brought into contact with the machined surface. The process damping phenomenon is stably expressed, and chatter vibration is stably suppressed.

In the cutting tool, a plurality of the first convex portions are provided at intervals in the blade length direction in which the cutting edge extends, and a plurality of the second convex portions are provided at intervals in the blade length direction. The first convex portion and the second convex portion may be alternately arranged in the blade length direction.

In this case, since a plurality of first convex portions are arranged at intervals in the blade length direction of the cutting edge, welding may occur between the cutting edge and the first convex portion, or the cutting edge may be damaged by welding. Can be suppressed. Further, since the first convex portion and the second convex portion are alternately arranged in the blade length direction, the region where the convex portion is not arranged can be kept small in the blade length direction. In other words, in the blade length direction, the process damping effect due to the convex portion is exhibited in a wide range, and the chatter vibration is suppressed more stably.

In the cutting tool, the first convex portion may extend in the blade length direction in which the cutting edge extends, and the second convex portion may extend in the blade length direction.

In this case, the process damping effect of each convex portion can be exhibited in a wide range in the blade length direction.

In the cutting tool, the plurality of the convex portions have a plurality of first convex portions arranged at intervals in the blade length direction in which the cutting edge extends, and each of the first convex portions has the blade length. It may extend in a direction intersecting the direction.

In this case, since a plurality of first convex portions are arranged at intervals in the blade length direction of the cutting edge, welding may occur between the cutting edge and the first convex portion, or the cutting edge may be damaged by welding. Can be suppressed. Further, since the first convex portion extends in the direction intersecting the blade length direction, the first convex portion can expand the vibration wavelength region in which the process damping effect is exhibited, and chatter vibration is stably suppressed. ..

In the cutting tool, the plurality of the convex portions have a plurality of first convex portions arranged at intervals in the blade length direction in which the cutting edge extends, and each of the first convex portions has the blade length. It may extend in the direction in which the direction orthogonal to the direction and the blade length direction are combined.

In this case, since a plurality of first convex portions are arranged at intervals in the blade length direction of the cutting edge, welding may occur between the cutting edge and the first convex portion, or the cutting edge may be damaged by welding. Can be suppressed. Further, since the first convex portion extends at least in the direction orthogonal to the blade length direction, the first convex portion can expand the vibration wavelength region in which the process damping effect is exhibited. Specifically, the first convex portion. Since the portion extends in the direction orthogonal to the blade length direction and the direction in which the blade length direction is combined, the process damping effect of the first convex portion can be exhibited in a wide range in the blade length direction.

In the cutting tool, the convex portion has a top surface facing radially outward in the radial direction or facing the tip side in the axial direction, and the tool rotation direction, and the top surface and the flank surface. The top surface may have a front surface to be connected, and the amount of protrusion from the flank may increase toward the counter-tool rotation direction.

In this case, the top surface of each convex portion has a larger amount of protrusion from the flank toward the anti-tool rotation direction, that is, the top surface is inclined with respect to the flank. For this reason, the inclination of the top surface of the convex portion with respect to the machined surface (angle corresponding to the clearance angle of the top surface) can be made smaller than the clearance angle of the clearance surface with respect to the machined surface of the work material, and chatter vibration occurs during cutting. When this is done, this top surface can be stably brought into contact with the machined surface. As a result, the process damping phenomenon is stably expressed, and chatter vibration is stably suppressed.

Further, one aspect of the present invention is a cutting method for cutting a machined surface of a work material with a cutting tool rotated in the circumferential direction around the tool axis, wherein the cutting tool is a tool in the circumferential direction. A rake face facing the rotation direction, a flank facing the outside in the radial direction in the radial direction orthogonal to the tool axis, a cutting edge formed on a ridge line connecting the rake face and the flank surface, and the flank surface. The flank is provided with a convex portion that protrudes from the cutting tool and is disposed away from the cutting edge, and the flank is radially inward in the radial direction from the cutting edge toward the anti-tool rotation direction in the circumferential direction. A plurality of the convex portions are provided on the flank, and pass over the cutting edge of a virtual circle that passes through the cutting tool centering on the tool axis in a cross-sectional view perpendicular to the tool axis. The clearance angle formed between the tangent line and the flank is γn, the maximum wear width of the flank along the circumferential direction is VBmax, and the virtual circle and each convex portion in the radial direction. The distance H between them is VBmax · tanγn or more.

According to the cutting method of the present invention, the radial distance H between the virtual circle (corresponding to the machined surface of the work material) and each convex portion, that is, the withdrawal distance of each convex portion with respect to the machined surface of the work material. A certain distance H is VBmax · tanγn or more. Therefore, chatter vibration can be stably suppressed by the plurality of convex portions until the flank wear of the cutting tool becomes maximum and the tool life is reached.

Further, one aspect of the present invention is a cutting method for cutting a machined surface of a work material with a cutting tool rotated in the circumferential direction around the tool axis, wherein the cutting tool is a tool in the circumferential direction. A rake face facing the rotation direction, a flank facing the tip side in the axial direction in which the tool axis extends, a cutting tool formed on a ridge connecting the rake face and the flank, and a cutting tool protruding from the flank. The flank is provided with a convex portion arranged away from the cutting tool, and the flank is directed toward the proximal end side of the axial direction from the cutting tool toward the anti-tool rotation direction in the circumferential direction. A plurality of inclined portions are provided on the flank surface, and the virtual plane on which the cutting edge is located perpendicular to the tool axis is used as a machining reference surface, and the convex portion is viewed from a radial direction orthogonal to the tool axis. The clearance angle formed between the flank and the machining reference surface is γn, the maximum wear width of the flank along the circumferential direction is VBmax, and the machining reference surface and each of the convex portions in the axial direction. The distance H between and is VBmax · tanγn or more.

According to the cutting method of the present invention, the axial distance H between the machining reference surface (corresponding to the machining surface of the work material) and each convex portion, that is, the withdrawal distance of each convex portion with respect to the machining surface of the work material. The distance H is VBmax · tanγn or more. Therefore, chatter vibration can be stably suppressed by the plurality of convex portions until the flank wear of the cutting tool becomes maximum and the tool life is reached.

According to the cutting tool and the cutting method according to one aspect of the present invention, chatter vibration can be stably suppressed.

FIG. 1 is a perspective view showing a cutting edge replaceable cutting tool according to the first embodiment of the present invention. FIG. 2 is a top view showing a cutting insert of a cutting edge replaceable cutting tool. FIG. 3 is a front view showing a cutting insert of a cutting edge replaceable cutting tool. FIG. 4 is a side view showing a cutting insert of a cutting edge replaceable cutting tool. FIG. 5 is a cross-sectional view showing a VV cross section of FIG. FIG. 6 is a cross-sectional view showing the vicinity of the cutting edge, and is a diagram illustrating the operation and effect of the present invention. FIG. 7 is a graph showing the chatter vibration suppression region of each convex portion, the horizontal axis represents the frequency band of chatter vibration, and the vertical axis represents the distance from the cutting edge to the convex portion. FIG. 8 is a graph showing a chatter vibration suppression region of each convex portion, the horizontal axis represents the frequency band of chatter vibration, and the vertical axis represents the distance from the cutting edge to the convex portion. FIG. 9 is an enlarged front view showing the vicinity of the cutting edge of the cutting insert of the first modification of the first embodiment. FIG. 10 is a cross-sectional view showing an XX cross section of FIG. FIG. 11 is an enlarged front view showing the vicinity of the cutting edge of the cutting insert of the second modification of the first embodiment. FIG. 12 is a cross-sectional view showing a cross section of XII-XII of FIG. FIG. 13 is an enlarged front view showing the vicinity of the cutting edge of the cutting insert of the third modification of the first embodiment. FIG. 14 is a cross-sectional view showing a cross section of XIV-XIV of FIG. FIG. 15 is an enlarged front view showing the vicinity of the cutting edge of the cutting insert of the fourth modification of the first embodiment. FIG. 16 is an enlarged cross-sectional view showing the vicinity of the cutting edge of the cutting insert of the fourth modification of the first embodiment. FIG. 17 is a perspective view showing a solid end mill according to a second embodiment of the present invention. FIG. 18 is a front view of the solid end mill as viewed from the axial direction. FIG. 19 is a cross-sectional view showing the vicinity of the outer peripheral blade of the solid end mill. FIG. 20 is a cross-sectional view showing the vicinity of the outer peripheral blade of the solid end mill. FIG. 21 is a side view showing the vicinity of the outer peripheral blade of the solid end mill. FIG. 22 is a side view showing the vicinity of the tip blade of the solid end mill.

<First Embodiment>
A cutting tool with a replaceable cutting edge, which is a cutting tool according to the first embodiment of the present invention, and a cutting method using the cutting tool will be described with reference to FIGS. 1 to 16.
The cutting edge replaceable cutting tool 10 of the present embodiment is a turning tool. The cutting edge replaceable cutting tool 10 turns the machined surface MS of a metal work material such as carbon steel.

As shown in FIG. 1, the cutting edge replaceable cutting tool 10 includes a holder 1, a cutting insert 2, and a clamp screw 3.
The holder 1 is made of, for example, a steel material. The holder 1 is a columnar rod body. In the example of this embodiment, the holder 1 is a quadrangular columnar shape. The holder 1 is detachably attached to a tool post or the like of a machine tool (not shown). The holder 1 has an insert mounting seat 4 at the tip of the holder 1. The insert mounting seat 4 has a concave shape that is recessed from the outer surface of the tip end portion of the holder 1. The insert mounting seat 4 has a polygonal concave shape or a circular concave shape, and in the example of the present embodiment, it has a triangular concave shape.

The cutting insert 2 is made of, for example, cemented carbide. The cutting insert 2 is detachably fixed to the insert mounting seat 4 by the clamp screw 3. The cutting insert 2 has a plate shape. Specifically, the cutting insert 2 has a polygonal plate shape or a circular plate shape, and in the example of the present embodiment, it has a triangular plate shape.

As shown in FIGS. 2 to 5, the cutting insert 2 protrudes from the rake face 11, the flank 12, the cutting edge 13 formed on the ridge line connecting the rake face 11 and the flank 12, and the flank 12. A convex portion 14 arranged apart from the cutting edge 13 and a through hole 15 are provided. That is, the cutting edge replaceable tool (cutting tool) 10 includes a rake surface 11, a flank surface 12, a cutting edge 13, and a convex portion 14. The rake face 11 is arranged on the front surface 2a of the pair of plate surfaces of the cutting insert 2, that is, the front surface 2a and the back surface 2b. The flank surface 12 and the convex portion 14 are arranged on the outer peripheral surface of the cutting insert 2. The convex portion 14 is projected from the flank surface 12 at a position away from the cutting edge 13.

[Definition of direction]
In the present embodiment, the direction in which the central axis (insert central axis) C of the cutting insert 2 extends is referred to as an axial direction (insert axial direction). Of the axial directions, the direction from the back surface 2b of the cutting insert 2 to the front surface 2a is referred to as one axial direction, and the direction from the front surface 2a to the back surface 2b is referred to as the other axial direction.
The direction orthogonal to the central axis C is called the radial direction (insert radial direction). Of the radial directions, the direction closer to the central axis C is called the radial inner side, and the direction away from the central axis C is called the radial outer side.
The direction that orbits around the central axis C is called the circumferential direction (insert circumferential direction).

Further, as shown in FIG. 5, the virtual plane including the blade length direction in which the cutting edge 13 extends and the predetermined direction intersecting the cutting edge 13 is defined as the machining reference plane VS, and the direction orthogonal to the machining reference plane VS is the first direction D1. Called. In the present embodiment, the "blade length direction" refers to the direction in which the ridgeline of the cutting edge 13 extends, and the "predetermined direction" means that the machined surface MS of the work material and the cutting edge 13 vibrate during cutting. It is the apparent direction that can be moved relative to each other without the presence of, that is, the "cutting direction". In the present embodiment, the "predetermined direction" corresponds to the axial direction in which the central axis C extends.
Further, the "machining reference plane VS" may be paraphrased as a virtual plane including a ridgeline of the cutting edge 13 and a virtual straight line intersecting the ridgeline and extending in a predetermined direction (cutting direction).

Of the first direction D1, the direction (-D1 side) from the cutting edge 13 toward the inside of the tool (center axis C side) is called the inside of the first direction D1, and the direction from the cutting edge 13 to the outside of the tool (opposite to the center axis C) is called. ) Is called the outside of the first direction D1 (+ D1 side). The direction from the cutting edge 13 to the inside of the tool in the first direction D1, that is, the inside of the first direction D1 corresponds to the direction from the cutting edge 13 to the center of the cutting insert 2 in the first direction D1. The direction from the cutting edge 13 to the outside of the tool in the first direction D1, that is, the outside of the first direction D1 corresponds to the direction from the cutting edge 13 in the first direction D1 to the side opposite to the center of the cutting insert 2. ..
The outside of the first direction D1 is also the direction of the first direction D1 toward the flank 12 from the central axis C. The inside of the first direction D1 is also the direction from the flank surface 12 toward the central axis C in the first direction D1.
The above "predetermined direction" is referred to as a second direction D2. The second direction D2 is a direction orthogonal to the first direction D1. Of the second direction D2, the direction from the cutting edge 13 toward the convex portion 14 (-D2 side) is called the second direction D2 rear side, and the direction from the convex portion 14 toward the cutting edge 13 (+ D2 side) is the second direction. Called the front side of D2.
The direction orthogonal to the first direction D1 and the second direction D2 is called the third direction D3. In the present embodiment, the third direction D3 is the direction in which the cutting edge 13 extends, that is, corresponds to the blade length direction of the cutting edge 13. FIG. 5 shows a cross-sectional view perpendicular to the third direction D3, and in the present embodiment, corresponds to a cross-sectional view perpendicular to the cutting edge 13.

[Scooping surface]
The rake face 11 is arranged on a portion of the surface 2a of the cutting insert 2 adjacent to the cutting edge 13. The rake face 11 is arranged on the outer peripheral portion of the surface 2a. The rake face 11 extends along the cutting edge 13. The rake face 11 faces one side in the axial direction. In the example of this embodiment, the rake face 11 is a flat surface extending perpendicular to the central axis C. Although not particularly shown, the rake face 11 may be inclined toward the other side in the axial direction as it goes inward in the radial direction from the cutting edge 13. In this case, the rake angle of the rake face 11 is a positive angle. Further, the rake face 11 may be inclined toward one side in the axial direction from the cutting edge 13 toward the inside in the radial direction. In this case, the rake angle of the rake face 11 is a negative angle.

[Escape surface]
The flank 12 is arranged on a portion of the outer peripheral surface of the cutting insert 2 facing outward in the radial direction, which is adjacent to the cutting edge 13. The flank 12 extends along the cutting edge 13. The flank 12 is inclined inward in the radial direction from the cutting edge 13 toward the other side in the axial direction. Although not particularly shown, the flank 12 may extend from the cutting edge 13 toward the other side in the axial direction in parallel with the central axis C.
The flank 12 inclines toward the inside of the first direction D1 (-D1 side) from the cutting edge 13 toward the rear side (-D2 side) of the second direction D2.

As shown in FIG. 5, the angle (not shown) formed between the flank 12 and the central axis C in the cross-sectional view perpendicular to the third direction D3 (cross-sectional view orthogonal to the cutting edge 13) is the present. In the example of the embodiment, it corresponds to the clearance angle γn. The clearance angle γn is two angles (acute angle and superior angle) formed between the clearance surface 12 and the machined surface MS (machining reference surface VS) of the work material centering on the cutting edge 13 in this cross-sectional view. Of these, it is a small angle (that is, an acute angle).

What is indicated by the reference numeral VBmax in FIG. 5 is the maximum wear width of the flank 12 along the second direction D2 (along the machined surface MS of the work material). In this cross-sectional view, the wear width of the flank 12 along the second direction D2 (in this embodiment, the wear width of the flank 12 along the axial direction of the central axis C) of the cutting insert 2 has reached the maximum wear width VBmax. Sometimes it becomes difficult to maintain good cutting accuracy, and it is judged that the tool life has expired. In FIG. 5, the machined surface MS of the work material is machined inside the first direction D1 (that is, closer to the central axis C) than the machined surface MS when the flank surface 12 reaches the maximum wear width VBmax. Located on the surface MS'.

[Blade]
The cutting edge 13 extends along the outer peripheral edge of the surface 2a. As shown in FIG. 2, in the example of the present embodiment, the cutting edge 13 has a corner blade portion 13a and a straight blade portion 13b. The corner blade portion 13a has a convex curved shape protruding outward in the radial direction. The straight blade portion 13b is connected to the end portion of the corner blade portion 13a and extends linearly. In the present embodiment, a pair of straight blade portions 13b are connected to both ends of the corner blade portion 13a in the blade length direction. As shown in FIG. 2, when the cutting insert 2 is viewed from the axial direction (top view when the surface 2a is viewed from the front), the set of the corner blade portion 13a and the pair of straight blade portions 13b is approximately V as a whole. It is in the shape of a letter. The set of the corner blade portion 13a and the pair of straight blade portions 13b is provided at each of the plurality of corner portions of the cutting insert 2.

[Convex part]
As shown in FIGS. 1 and 5, the convex portion 14 is arranged in an intermediate portion of the outer peripheral surface of the cutting insert 2 located between both ends in the axial direction. The convex portion 14 is located on one side in the axial direction (cutting edge 13 side) of the intermediate portion. The convex portions 14 are provided on a plurality of corner portions of the outer peripheral surface of the cutting insert 2, respectively. The convex portion 14 is arranged at least on the rear side (−D2 side) of the cutting edge 13 (near the corner portion of the cutting insert 2 in the present embodiment) in the second direction (−D2 side), that is, on the other side in the axial direction.

As shown in FIGS. 3 to 5, a plurality of convex portions 14 are provided on the flank surface 12. The plurality of convex portions 14 may be arranged at intervals from each other, or may be partially connected to each other. In the example of the present embodiment, each convex portion 14 is rib-shaped and extends in the second direction D2, that is, in the axial direction on the flank surface 12. Each convex portion 14 is arranged at a distance from the cutting edge 13 in the axial direction, and extends in a direction intersecting the blade length direction of the cutting edge 13 (in the illustrated example, a direction orthogonal to the blade length direction).

As shown in FIG. 5, the convex portion 14 has a top surface 14a, a front surface 14b, and a rear surface 14c.
The top surface 14a faces the outside of D1 in the first direction (+ D1 side). The amount of protrusion of the top surface 14a from the flank 12 increases toward the rear side (−D2 side) of the second direction D2. In the example of this embodiment, the top surface 14a and the processing reference surface VS are parallel to each other in a cross-sectional view perpendicular to the third direction D3 shown in FIG.

In the example of this embodiment, the top surface 14a extends linearly in parallel with the central axis C in the cross-sectional view shown in FIG. That is, in this cross-sectional view, the angle formed between the top surface 14a and the flank surface 12 is equal to the angle formed between the central axis C and the flank surface 12. Further, in the example of the present embodiment, in this cross-sectional view, the angle formed between the top surface 14a and the flank surface 12 is formed between the flank surface 12 and the machining surface MS (machining reference plane VS). It is also equal to the clearance angle γn.

Of the plurality of convex portions 14, the top surface 14a of the convex portion 14 arranged on the rear side of the second direction D2 of the corner blade portion 13a, that is, on the other side in the axial direction, is a convex portion that is convex outward in the radial direction when viewed from the axial direction. It has a curved surface. Of the plurality of convex portions 14, the top surface 14a of the convex portions 14 arranged on the rear side of the straight blade portion 13b in the second direction D2 is planar. The convex portion 14 having the convex curved top surface 14a is arranged at the convex curved surface portion of the outer peripheral surface of the cutting insert 2, that is, the corner portion in the top view of the cutting insert 2. The convex portion 14 having the planar top surface 14a is arranged on the flat portion of the outer peripheral surface of the cutting insert 2, that is, on the side portion in the top view of the cutting insert 2.

As shown in FIG. 5, among the plurality of convex portions 14, the end portion on the front side (+ D2 side) of the second direction D2 on the top surface 14a of the convex portion 14 arranged closest to the cutting edge 13, and the cutting edge 13 The distance _lt along the second direction D2 between and is 0.3 mm or more. The distance _lt is 1.35 mm or less. The length of the top surface 14a in the second direction D2 is, for example, 0.03 mm or more and 2 mm or less. The height h of the first direction D1 between the end of the top surface 14a on the front side of the second direction D2 and the portion of the flank 12 connected to the front surface 14b is larger than (lt _−VBmax ) · tanγn. small. The height h is, for example, 0.002 mm or more and 0.1 mm or less. The height h may be, for example, 0.05 mm or less.

The front surface 14b faces the front side (+ D2 side) of the second direction D2, and connects the top surface 14a and the flank surface 12. The front surface 14b inclines toward the inside of the first direction D1 (-D1 side) and toward the front side of the second direction D2. In the example of this embodiment, the front surface 14b is linear in a cross-sectional view perpendicular to the third direction D3 shown in FIG.

As shown in FIG. 5, in a cross-sectional view perpendicular to the third direction D3, of the two angles (obtuse angle and dominant angle) formed between the top surface 14a and the front surface 14b, the smaller angle θ1 is the obtuse angle. be. That is, the angle θ1 is larger than 90 °. The angle θ1 is 150 ° or less. Although not particularly shown, the connecting portion between the top surface 14a and the front surface 14b may be formed in a convex curved surface shape, and in this case, adhesion to the convex portion 14 is further suppressed.
Further, in this cross-sectional view, of the two angles (obtuse angle and dominant angle) formed between the front surface 14b and the flank surface 12, the smaller angle θ2 is an obtuse angle. That is, the angle θ2 is larger than 90 °. The angle θ2 is 143 ° or less.

The rear surface 14c faces the rear side (-D2 side) of the second direction D2, and connects the top surface 14a and the flank surface 12. The rear surface 14c inclines toward the rear side of the second direction D2 as it goes inward in the first direction D1. In the example of this embodiment, the rear surface 14c is linear in the cross-sectional view shown in FIG.

As shown in FIGS. 3 to 5, the plurality of convex portions 14 have a first convex portion 14A and a second convex portion 14B.
The first convex portion 14A is a convex portion 14 arranged closest to the cutting edge 13 among the plurality of convex portions 14. The second convex portion 14B is located behind the first convex portion 14A in the second direction D2. In the example of the present embodiment, the second convex portion 14B is the convex portion 14 arranged at the farthest distance from the cutting edge 13 among the plurality of convex portions 14. The amount of protrusion of the second convex portion 14B from the flank surface 12 is larger than the amount of protrusion of the first convex portion 14A from the flank surface 12.

A plurality of first convex portions 14A are provided at intervals in the blade length direction of the cutting edge 13. In the example of the present embodiment, the plurality of first convex portions 14A are arranged in the third direction D3 at intervals from each other. Each first convex portion 14A extends in the second direction D2, that is, in the axial direction. A plurality of second convex portions 14B are provided at intervals in the blade length direction of the cutting edge 13. In the example of this embodiment, the plurality of second convex portions 14B are arranged in the third direction D3 at intervals from each other. Each second convex portion 14B extends in the second direction D2, that is, in the axial direction. The first convex portion 14A and the second convex portion 14B are alternately arranged in the blade length direction of the cutting edge 13.

The length (width) of the first convex portion 14A and the second convex portion 14B along each blade length direction is, for example, 0.050 mm or more and 1.000 mm or less, respectively. The distance (interval) between the first convex portions 14A and 14A adjacent to each other in the blade length direction and the distance between the second convex portions 14B and 14B adjacent to each other in the blade length direction are, for example, 0.050 mm or more and 1.000 mm, respectively. It is as follows.
In the example of the present embodiment, among the plurality of first convex portions 14A, the width of the first convex portion 14A located on the convex curved surface portion (corner portion) of the outer peripheral surface of the cutting insert 2 in the blade length direction is the width of the cutting insert 2. It is larger than the width in the blade length direction of the first convex portion 14A located on the flat surface portion (side portion) of the outer peripheral surface of the above. Further, among the plurality of second convex portions 14B, the width of the second convex portion 14B located on the convex curved surface portion (corner portion) of the outer peripheral surface of the cutting insert 2 in the blade length direction is the plane of the outer peripheral surface of the cutting insert 2. It is larger than the width of the second convex portion 14B located at the portion (side portion) in the blade length direction.

The length of the second convex portion 14B in the second direction D2 is longer than the length of the first convex portion 14A in the second direction D2. As shown in FIG. 5, when viewed from the blade length direction of the cutting edge 13, that is, the third direction D3, the end portion on the rear side of the second direction D2 of the first convex portion 14A and the second direction D2 of the second convex portion 14B. It overlaps with the front end. The first convex portion 14A and the second convex portion 14B do not have to overlap each other when viewed from the blade length direction of the cutting edge 13, that is, the third direction D3.
In the present embodiment, the length of the top surface 14a of the first convex portion 14A in the second direction D2 and the length of the top surface 14a of the second convex portion 14B in the second direction D2 are the same as each other. The length of the top surface 14a of the first convex portion 14A in the second direction D2 may be longer than the length of the top surface 14a of the second convex portion 14B in the second direction D2. Further, the length of the top surface 14a of the first convex portion 14A in the second direction D2 may be shorter than the length of the top surface 14a of the second convex portion 14B in the second direction D2.

In this embodiment, an example is given in which a plurality of convex portions 14 have a first convex portion 14A and a second convex portion 14B, but the present invention is not limited to this. For example, the plurality of convex portions 14 may have a third convex portion located behind the second convex portion 14B in the second direction D2. Further, the plurality of convex portions 14 may have a fourth convex portion located on the rear side of the second direction D2 with respect to the third convex portion. A plurality of third convex portions and a plurality of fourth convex portions are provided on the flank surface 12. The amount of protrusion of the third convex portion from the flank surface 12 is larger than the amount of protrusion of the second convex portion 14B from the flank surface 12. Further, the amount of protrusion of the fourth convex portion from the flank surface 12 is larger than the amount of protrusion of the third convex portion from the flank surface 12. Further, the plurality of convex portions 14 may have a fifth convex portion, a sixth convex portion, ..., As described above.

[Through hole]
As shown in FIGS. 1 and 2, the through hole 15 opens in the front surface 2a and the back surface 2b of the cutting insert 2. The through hole 15 extends axially inside the cutting insert 2. The through hole 15 has a multi-stage circular hole shape centered on the central axis C. The inner diameter of the through hole 15 is gradually reduced from the end on one side in the axial direction toward the other side in the axial direction. The clamp screw 3 is inserted into the through hole 15. Although not particularly shown, the male screw portion of the clamp screw 3 inserted into the through hole 15 is screwed into the female screw hole of the insert mounting seat 4. As a result, the cutting insert 2 is detachably fixed to the insert mounting seat 4.

[Cutting method]
Next, a cutting method for cutting the machined surface MS of the work material with the cutting edge replaceable tool (cutting tool) 10 of the present embodiment will be described.
As shown in FIG. 5, in a cross-sectional view perpendicular to the third direction D3, the clearance angle formed between the flank surface 12 and the machining reference plane VS (machining surface MS) is γn, and is along the second direction D2. The maximum wear width of the flank 12 is VBmax. In the cutting method of the present embodiment, the distance H between the machining reference surface VS and each convex portion 14 in the first direction D1 (corresponding to the radial direction in the example of the present embodiment) is VBmax · tanγn or more. Further, the top surface 14a of each convex portion 14 is parallel to the machined surface MS, respectively.

[Action and effect of this embodiment]
According to the cutting edge replaceable tool (cutting tool) 10 of the present embodiment described above, since the convex portion 14 protruding from the flank surface 12 is provided, for example, during cutting (turning) under low cutting speed conditions, for example, A phenomenon called process damping appears and chatter vibration is suppressed. Process damping is a phenomenon in which, when chatter vibration occurs during cutting, the flank of the cutting tool comes into contact with the machined surface of the work material, causing a vibration damping effect. That is, in the present embodiment, by providing the convex portion 14 on the flank surface 12, the convex portion 14 easily comes into contact with the machined surface MS of the work material, so that the process damping phenomenon can be positively exhibited and chattering can occur. Vibration can be suppressed.

Further, in the present embodiment, since a plurality of convex portions 14 are provided on the flank surface 12, the distance _lt , the shape, the amount of protrusion from the flank surface 12, and the length of the second direction D2 of each convex portion 14 from the cutting edge 13 are provided. By appropriately setting the length in the third direction D3 or the length in the blade length direction, etc., the vibration wavelength region in which the process damping effect is exhibited can be made different for each convex portion 14, thereby causing chatter vibration. The suppressable frequency range can be extended. Therefore, it is possible to suppress chatter vibration in a wide frequency band. Therefore, according to the present embodiment, chatter vibration can be stably suppressed.

The action of suppressing chatter vibration in a wide frequency band by the plurality of convex portions 14 will be described in detail.
The inventor of the present invention has obtained through experiments and the like that the process damping effect of the convex portion 14 is likely to be exhibited when the condition of the following formula (1) is satisfied.

Actually, considering the periodicity of the wave, it is considered that the effect is likely to appear within the range of the above equation (2).
Here, assuming that the frequency of chatter vibration is f _c and the cutting speed is v _c , the wavelength of vibration is λ = v _c / f _c . Therefore, the above equation (1) is expressed as a relational expression between speed and frequency as in the above equation (3).

According to the above relational expression, for example, as shown in FIG. 6, the chatter vibration suppressing effect when the first convex portion 14A, the second convex portion 14B, and the third convex portion 14C are projected on the flank surface 12 will be considered. In FIG. 6, the distance l _t along the second direction D2 between the end portion on the front side of the first convex portion 14A (top surface 14a) in the second direction D2 and the cutting edge 13 is represented by l _ta . The distance _{lt along the second direction D2 between the end of the second convex portion 14B (top surface 14a) on the front side of the second direction D2 and the cutting edge 13 is represented by l tb ,} and the third convex portion 14C The distance _{lt along the second direction D2 between the end portion on the front side of the second direction D2 of (top surface 14a) and the cutting edge 13 is represented by l ct .} Specifically, for example, the distance l _ta is 0.55 mm, the distance l _tb is 0.87 mm, and the distance l _tc is 1.25 mm. The length of each convex portion 14 (top surface 14a) along the second direction D2 is, for example, 0.1 mm.

As shown in the graph of FIG. 7, when the cutting speed v _c = 100 m / min, the first convex portion 14A has a process damping effect in the frequency range of 151.5 to 1515 Hz or 3182 to 4545 Hz according to the above equation (3). Can be expected to be expressed. Similarly, the second convex portion 14B and the third convex portion 14C can be expected to exhibit a process damping effect in a frequency range such as 2011 to 2874 Hz and 1400 to 2000 Hz, respectively. Further, the graph of FIG. 8 shows a frequency range in which the first convex portion 14A, the second convex portion 14B and the third convex portion 14C are expected to exhibit a process damping effect when the cutting speed v _c = 150 m / min. Is shown.
From FIG. 7, when the cutting speed v _c = 100 m / min, a plurality of convex portions 14 are provided on the flank surface 12, so that process damping is robustly performed in a wide frequency band from low frequency to about 5 kHz. It is considered possible to exert the effect. Further, from FIG. 8, when the cutting speed v _c = 150 m / min, a plurality of convex portions 14 are provided on the flank surface 12, so that the process is robust in a wide frequency band from low frequency to about 7 kHz. It is considered possible to develop a damping effect.
Therefore, according to the present invention, chatter vibration can be stably suppressed.

Further, in the present embodiment, as shown in FIG. 5, a plurality of convex portions 14 have a first convex portion 14A and a second convex portion 14B in which the positions of the second directions D2 are different from each other.
In this case, the frequency range in which the first convex portion 14A exhibits the process damping effect and the frequency range in which the second convex portion 14B exhibits the process damping effect can be made different from each other, and it becomes robust in a wide frequency band. The process damping effect can be exhibited.

Further, in the present embodiment, the amount of protrusion of the second convex portion 14B from the flank surface 12 is larger than the amount of protrusion of the first convex portion 14A from the flank surface 12. That is, among the plurality of convex portions 14, the convex portion 14 farther from the cutting edge 13 in the second direction D2 has a larger amount of protrusion from the flank surface 12.
In this case, the distance in the first direction D1 between the machined surface MS (machining reference surface VS) of the work material and the first convex portion 14A, and between the machined surface MS of the work material and the second convex portion 14B. The difference from the distance in the first direction D1 of the above can be reduced, or each distance can be made the same. As a result, when chatter vibration occurs during cutting, each convex portion 14 can be stably brought into contact with the machined surface MS. The process damping phenomenon is stably expressed, and chatter vibration is stably suppressed.

Further, in the present embodiment, since the plurality of first convex portions 14A are arranged at intervals in the blade length direction of the cutting edge 13, welding occurs or welding occurs between the cutting edge 13 and the first convex portion 14A. Therefore, it is possible to prevent the cutting edge 13 from being damaged. Further, since the first convex portion 14A and the second convex portion 14B are alternately arranged in the blade length direction, the region where the convex portion 14 is not arranged can be kept small in the blade length direction. In other words, the process damping effect due to the convex portion 14 is exhibited over a wide range in the blade length direction, and chatter vibration is suppressed more stably.

Further, in the present embodiment, since the first convex portion 14A and the second convex portion 14B extend in the second direction D2, respectively, the first convex portion 14A has a vibration wavelength region in which the process damping effect is exhibited, and the second convex portion 14B. However, it becomes possible to expand the vibration wavelength region in which the process damping effect is exhibited, and chatter vibration is stably suppressed.

Further, in the present embodiment, the amount of protrusion of the top surface 14a of each convex portion 14 from the flank 12 increases toward the rear side of the second direction D2, that is, the top surface 14a is inclined with respect to the flank 12. is doing. Therefore, in a cross-sectional view perpendicular to the third direction D3 shown in FIG. 5, the convex portion with respect to the machined surface MS rather than the clearance angle γn of the clearance surface 12 with respect to the machined surface MS (corresponding to the machined reference surface VS) of the work material. The inclination of the top surface 14a of 14 (an angle corresponding to the clearance angle of the top surface 14a) can be reduced, and when chatter vibration occurs during cutting, the top surface 14a can be stably brought into contact with the machined surface MS. .. As a result, the process damping phenomenon is stably expressed, and chatter vibration is stably suppressed.

Further, in the present embodiment, the front surface 14b of the convex portion 14 is inclined toward the front side of the second direction D2 toward the inside of the first direction D1 in a cross-sectional view perpendicular to the third direction D3 shown in FIG. Since the angle θ1 formed between the top surface 14a and the front surface 14b is an obtuse angle, the work material can be used at the connection portion between the top surface 14a and the front surface 14b and the connection portion between the flank surface 12 and the front surface 14b. Adhesion and accumulation are suppressed. As a result, the deposition of adhered matter on the convex portion 14 and the flank surface 12 is suppressed, and the cutting edge defect of the cutting edge 13 is suppressed. Further, since the front surface 14b is inclined, it is possible to suppress cutting of the machined surface MS when the convex portion 14 comes into contact with the machined surface MS, and the machined surface accuracy is ensured.
Of the "two angles formed between the top surface 14a and the front surface 14b in the cross-sectional view perpendicular to the third direction D3", the larger angle (angle other than the small angle θ1) is the top surface 14a and the front surface 14b. Refers to the dominant angle formed between and, that is, an angle of more than 180 ° and less than 360 °.

Further, in the present embodiment, since the angle θ1 formed between the top surface 14a and the front surface 14b is 150 ° or less in the cross-sectional view perpendicular to the third direction D3, the front surface 14b is the machined surface MS of the work material. It is suppressed that it is arranged substantially parallel to (corresponding to the machining reference plane VS). As a result, when chatter vibration occurs during cutting, it is possible to prevent the front surface 14b of the convex portion 14 from coming into contact with the machined surface MS of the work material. Since the top surface 14a of the convex portion 14 is stably brought into contact with the machined surface MS, chatter vibration in a desired frequency band can be stably suppressed.

Further, in the present embodiment, since the angle θ2 formed between the front surface 14b of the convex portion 14 and the flank 12 is an obtuse angle in a cross-sectional view perpendicular to the third direction D3, the front surface 14b and the flank 12 Adhesion of the work material is suppressed from adhering to or accumulating on the connection portion. As a result, the deposition of adhered matter on the convex portion 14 and the flank surface 12 is suppressed, and the cutting edge defect of the cutting edge 13 is suppressed.
The larger angle (angle other than the small angle θ2) among the “two angles formed between the front surface 14b and the flank surface 12 in the cross-sectional view perpendicular to the third direction D3” is the front surface 14b and the flank surface 12. Refers to the dominant angle formed between and, that is, an angle of more than 180 ° and less than 360 °.

Further, in the present embodiment, since the angle θ2 formed between the front surface 14b and the flank 12 is 143 ° or less in the cross-sectional view perpendicular to the third direction D3, the front surface 14b is the machined surface MS of the work material. It is suppressed that it is arranged substantially parallel to (corresponding to the machining reference plane VS). As a result, when chatter vibration occurs during cutting, it is possible to prevent the front surface 14b of the convex portion 14 from coming into contact with the machined surface MS of the work material. Since the top surface 14a of the convex portion 14 is stably brought into contact with the machined surface MS, chatter vibration in a desired frequency band can be stably suppressed.

Further, in the present embodiment, among the plurality of convex portions 14, the front end portion in the second direction D2 on the top surface 14a of the convex portion 14 (that is, the first convex portion 14A) arranged closest to the cutting edge 13 and the cutting edge portion 14 are cut. Since the distance _lt in the second direction D2 between the blade 13 and the blade 13 is 0.3 mm or more, the convex portion 14 (first convex portion 14A) escapes even if the flank wear progresses due to cutting. Wearing with the surface 12 is suppressed. Therefore, the process damping phenomenon is stably exhibited by the convex portion 14, and the chatter vibration is stably suppressed. The function of the cutting edge replaceable tool (cutting tool) 10 is maintained well for a long period of time, and the tool life is extended.
Further, since the convex portion 14 is arranged so as not to be too close to the cutting edge 13, the process damping phenomenon can be exhibited while suppressing the contact resistance between the convex portion 14 and the machined surface MS of the work material to be small.

Further, in the present embodiment, since the distance _lt is 1.35 mm or less, it is possible to stably obtain the process damping action by the convex portion 14 with respect to the frequency band of the chatter vibration generated during cutting. That is, the effect of the present invention can be obtained robustly over a wide frequency band. Further, regardless of the size of the clearance angle γn during cutting, that is, even if the clearance angle γn is set large, the convex portion 14 can be stably brought into contact with the machined surface MS of the work material. The process damping phenomenon is stably exhibited by the convex portion 14, and chatter vibration is stably suppressed.

Further, in the present embodiment, since the length of the top surface 14a of the convex portion 14 in the second direction D2 is 2 mm or less, the contact area and contact area between the top surface 14a and the machined surface MS of the work material are kept small. Be done. Therefore, it is possible to suppress the frictional resistance in the tangential direction (cutting direction, that is, the second direction D2) due to the contact between the convex portion 14 and the machined surface MS. In addition, it is possible to prevent the adhered material of the work material from adhering to the convex portion 14.

Further, in the present embodiment, the top surface 14a and the processing reference surface VS are parallel to each other in a cross-sectional view perpendicular to the third direction D3.
In this case, the top surface 14a of the convex portion 14 can be stably brought into contact with the machined surface MS of the work material. Therefore, chatter vibration is stably suppressed.

Although not particularly shown, the top surface 14a may extend inward in the first direction D1 in a cross-sectional view perpendicular to the third direction D3 as it goes toward the rear side of the second direction D2.
In this case, the top surface 14a of the convex portion 14 is inclined so as to be separated from the machined surface MS of the work material in the first direction D1 toward the rear side of the second direction D2. The process damping phenomenon can be exhibited while suppressing the contact resistance between the top surface 14a of the convex portion 14 and the machined surface MS of the work material to be small, and chatter vibration can be stably suppressed.

Further, according to the cutting method of the present embodiment, the distance H between the machining reference surface VS (corresponding to the machining surface MS of the work material) and each convex portion 14, that is, each convex portion with respect to the machining surface MS of the work material. The distance H, which is the evacuation distance of 14, is VBmax · tanγn or more. Therefore, chatter vibration can be stably suppressed by the plurality of convex portions 14 until the flank wear of the cutting insert 2 of the cutting edge replaceable cutting tool 10 becomes maximum and the tool life is reached.

[Modified example of the first embodiment]
FIG. 9 is a front view showing the vicinity of the cutting edge 13 of the cutting insert 2 of the first modification of the first embodiment. FIG. 10 is a cross-sectional view showing the vicinity of the cutting edge 13 of the cutting insert 2 of the first modification of the first embodiment, and shows the XX cross section of FIG.
As shown in FIGS. 9 and 10, in this first modification, a plurality of first modifications 14 are arranged so as to be spaced apart from each other in the blade length direction (third direction D3) of the cutting edge 13. It has a convex portion 14A. Further, each first convex portion 14A extends in the second direction D2.

According to this first modification, since the plurality of first convex portions 14A are arranged at intervals in the blade length direction of the cutting edge 13, welding occurs between the cutting edge 13 and the first convex portion 14A. It is also possible to prevent the cutting edge 13 from being damaged by welding. Further, since the first convex portion 14A extends in the second direction D2, the first convex portion 14A can expand the vibration wavelength region in which the process damping effect is exhibited, and chatter vibration is stably suppressed.

FIG. 11 is a front view showing the vicinity of the cutting edge 13 of the cutting insert 2 of the second modification of the first embodiment. FIG. 12 is a cross-sectional view showing the vicinity of the cutting edge 13 of the cutting insert 2 of the second modification of the first embodiment, and shows the cross section of XII-XII of FIG.
As shown in FIGS. 11 and 12, in this second modification, the plurality of convex portions 14 have a first convex portion 14A, a second convex portion 14B, and a third convex portion 14C. The first convex portion 14A, the second convex portion 14B, and the third convex portion 14C each extend in the blade length direction (third direction D3) of the cutting edge 13.
According to this second modification, the process damping effect of each convex portion 14 can be exhibited in a wide range in the blade length direction. The second modification is suitable for, for example, cutting a work material in which welding is unlikely to occur.

FIG. 13 is a front view showing the vicinity of the cutting edge 13 of the cutting insert 2 of the third modification of the first embodiment. FIG. 14 is a cross-sectional view showing the vicinity of the cutting edge 13 of the cutting insert 2 of the third modification of the first embodiment, and shows the XIV-XIV cross section of FIG.
As shown in FIGS. 13 and 14, in this third modification, the plurality of convex portions 14 are arranged at intervals in the blade length direction (third direction D3) of the cutting edge 13. It has a convex portion 14A. Further, each first convex portion 14A extends in the blade length direction toward the second direction D2. That is, as shown in FIG. 13, each first convex portion 14A is inclined and extends with respect to the blade length direction of the cutting edge 13 and the direction orthogonal to the cutting edge 13 when viewed from the first direction D1. That is, each first convex portion 14A extends in the direction (oblique direction) in which the blade length direction and the second direction D2 are combined.

According to this third modification, since the plurality of first convex portions 14A are arranged at intervals in the blade length direction of the cutting edge 13, welding occurs between the cutting edge 13 and the first convex portion 14A. It is also possible to prevent the cutting edge 13 from being damaged by welding. Further, since the first convex portion 14A extends at least in the second direction D2, the first convex portion 14A can expand the vibration wavelength region in which the process damping effect is exhibited. Specifically, the first convex portion Since 14A extends in the direction in which the blade length direction and the second direction D2 are combined, the process damping effect of the first convex portion 14A can be exhibited in a wide range in the blade length direction.

FIG. 15 is a front view showing the vicinity of the cutting edge 13 of the cutting insert 2 of the fourth modification of the first embodiment. FIG. 16 is a cross-sectional view showing the vicinity of the cutting edge 13 of the cutting insert 2 of the fourth modification of the first embodiment.
As shown in FIGS. 15 and 16, in this fourth modification, the plurality of convex portions 14 have a first convex portion 14A and a second convex portion 14B. A plurality of first convex portions 14A are provided side by side in the blade length direction (third direction D3) of the cutting edge 13. The plurality of first convex portions 14A include one first convex portion 14A extending along the second direction D2 and another first convex portion 14A extending inclined with respect to the second direction D2 and the third direction D3. And, are included. The second convex portion 14B extends along the third direction D3.
According to this fourth modification, the effects of the above-described embodiment and each modification can be obtained.

<Second Embodiment>
Next, the solid end mill 20 which is the cutting tool of the second embodiment of the present invention and the cutting method using the cutting tool will be described with reference to FIGS. 17 to 22. In the second embodiment, the same components as those in the first embodiment may be given the same name or the same reference numerals, and the description thereof may be omitted.

The solid end mill 20 of this embodiment is a milling tool. The solid end mill 20 is rotated in the circumferential direction around the tool axis O. At least the blade portion 20a described later of the solid end mill 20 is made of, for example, cemented carbide, high-speed tool steel, or the like. As shown in FIGS. 17 and 18, in the example of this embodiment, the solid end mill 20 is a square end mill. The solid end mill 20 mills the machined surface MS of a metal work material such as carbon steel.

The solid end mill 20 is a columnar shape extending along the tool axis O. The solid end mill 20 has a blade portion 20a and a shank portion (not shown). The blade portion 20a and the shank portion are arranged at different positions in the direction in which the tool axis O extends. The shank portion is detachably attached to a spindle or the like of a machine tool (not shown).

The blade portion 20a is an outer peripheral blade formed on a ridge line connecting a chip discharge groove 21, an outer peripheral rake surface (rake surface) 22, an outer peripheral escape surface (relief surface) 23, and an outer peripheral rake surface 22 and an outer peripheral escape surface 23. (Cut blade) 24, outer peripheral convex portion (convex portion) 25 protruding from the outer peripheral flank 23 and arranged away from the outer peripheral blade 24, tip rake surface (rake surface) 26, and tip flank surface (flank surface). 27, a tip blade (cutting blade) 28 formed on a ridge line connecting the tip rake surface 26 and the tip escape surface 27, and a tip convex portion (convex) that protrudes from the tip escape surface 27 and is arranged away from the tip blade 28. Part) 29 and.
That is, the solid end mill (cutting tool) 20 includes rake surfaces 22, 26, flanks 23, 27, cutting edges 24, 28, and convex portions 25, 29.

The outer peripheral rake face 22 is arranged on the wall surface 21b of the chip discharge groove 21 facing the tool rotation direction T. The outer peripheral flank 23 and the outer peripheral convex portion 25 are arranged on the outer peripheral surface of the solid end mill 20. The outer peripheral convex portion 25 is projected from the outer peripheral escape surface 23 at a position away from the outer peripheral blade 24.
The tip rake face 26 is arranged on the wall surface 21b of the chip discharge groove 21 facing the tool rotation direction T. The tip flank surface 27 and the tip convex portion 29 are arranged on the tip surface of the solid end mill 20. The tip convex portion 29 is projected from the tip flank surface 27 at a position away from the tip blade 28.

[Definition of direction]
In the present embodiment, the direction in which the tool axis (tool center axis) O of the solid end mill 20 extends is referred to as an axial direction (tool axis direction). The Z-axis direction shown in each figure corresponds to the axial direction. In the following description, the tool axis O may be simply referred to as the axis O. Of the axial directions, the direction from the shank portion (not shown) toward the blade portion 20a is referred to as the tip end side (+ Z side), and the direction from the blade portion 20a toward the shank portion is referred to as the base end side (-Z side).
The direction orthogonal to the axis O is called the radial direction (tool radial direction). Of the radial directions, the direction closer to the axis O is called the radial inner side, and the direction away from the axis O is called the radial outer side.
The direction that orbits around the axis O is called the circumferential direction (tool circumferential direction). Of the circumferential directions, the direction in which the solid end mill 20 is rotated by the spindle of the machine tool or the like is called the tool rotation direction T (+ T side), and the direction opposite to the tool rotation direction T is called the anti-tool rotation direction (-T side). Call. In the present embodiment, in the "circumferential direction" around the axis O, that is, the "circumferential direction" centered on the axis O, the machined surface MS of the work material and the cutting edges 24 and 28 vibrate during cutting. It is the apparent direction that can be moved relative to each other, that is, the "cutting direction".

[Chip discharge groove]
The chip discharge groove 21 has a groove shape that is recessed from the outer peripheral surface of the blade portion 20a. The chip discharge groove 21 opens in the tip surface of the blade portion 20a, and twists and extends in the counter-tool rotation direction from the tip surface of the blade portion 20a toward the proximal end side in the axial direction. A plurality of chip discharge grooves 21 are provided on the outer periphery of the blade portion 20a at intervals in the circumferential direction. In the present embodiment, two chip discharge grooves 21 are provided on the outer periphery of the blade portion 20a at equal pitch or unequal pitch in the circumferential direction.

[Outer rake surface]
The outer peripheral rake face 22 is arranged on the outer peripheral portion of the wall surface 21b of the chip discharge groove 21 facing the tool rotation direction T. The outer peripheral rake face 22 is arranged on a portion of the wall surface 21b of the chip discharge groove 21 facing the tool rotation direction T, which is adjacent to the outer peripheral blade 24. That is, the outer peripheral rake face 22 faces the tool rotation direction T. The outer peripheral rake surface 22 extends along the outer peripheral blade 24. The outer peripheral rake surface 22 has, for example, a concave curved surface.

[Outer peripheral flank]
The outer peripheral flank 23 is arranged on a portion of the outer peripheral surface of the blade portion 20a adjacent to the outer peripheral blade 24. The outer peripheral flank 23 is arranged adjacent to the outer peripheral blade 24 in the counter-tool rotation direction of the outer peripheral blade 24. The outer peripheral flank 23 faces radially outward. The outer peripheral flank 23 extends along the outer peripheral blade 24. The outer peripheral flank 23 is inclined inward in the radial direction from the outer peripheral blade 24 in the anti-tool rotation direction.

FIG. 19 is a cross-sectional view showing a cross section perpendicular to the axis O in the vicinity of the outer peripheral blade 24 of the solid end mill 20. FIG. 20 is a cross-sectional view showing a cross section perpendicular to the axis O in the vicinity of the outer peripheral blade 24 of the solid end mill 20, and shows a cross section in which the position of the axis O is different from that of FIG.
As shown in FIGS. 19 and 20, in the cross-sectional view perpendicular to the axis O, the virtual circle VC centered on the axis O and passing through the outer peripheral blade 24 corresponds to the machined surface MS of the work material. Specifically, the portion of the virtual circle VC including at least on the outer peripheral blade 24 corresponds to the machined surface MS. The virtual curved surface obtained by rotating the outer peripheral blade 24 around the axis O corresponds to the machined surface MS. This virtual curved surface may be rephrased as a machining reference surface. In each cross-sectional view of FIGS. 19 and 20, two angles formed between the tangent line passing over the outer peripheral blade 24 of the virtual circle VC (machined surface MS) and the outer peripheral flank 23 with the outer peripheral blade 24 as the center. Of (acute angles and dominant angles), the smaller angle (that is, the acute angle) corresponds to the clearance angle γn. The tangent line passing over the outer peripheral blade 24 of the virtual circle VC generally coincides with the machined surface MS (virtual circle VC) in the vicinity of the outer peripheral blade 24. Therefore, it can be said that the clearance angle γn is an angle formed between the outer peripheral clearance surface 23 and the machined surface MS around the outer peripheral blade 24 in each cross-sectional view.

What is indicated by the reference numeral VBmax in FIGS. 19 and 20, respectively, is the maximum wear width of the outer peripheral flank 23 along the circumferential direction (along the machined surface MS of the work material). In these cross-sectional views, when the wear width of the outer peripheral flank 23 along the circumferential direction reaches the maximum wear width VBmax, it becomes difficult for the solid end mill 20 to maintain good cutting accuracy, and it is determined that the tool life has been reached. To. In FIGS. 19 and 20, the machined surface MS of the work material is located on the machined surface MS'diameterally inside the machined surface MS when the outer peripheral flank 23 reaches the maximum wear width VBmax.

[Outer blade]
The outer peripheral blade 24 is arranged on the outer peripheral surface of the blade portion 20a. The outer peripheral blade 24 is located at the radial outer end of the blade portion 20a. The outer peripheral blade 24 extends along the outer peripheral edge of the wall surface 21b of the chip discharge groove 21 facing the tool rotation direction T. The outer peripheral blade 24 twists and extends in the anti-tool rotation direction from the tip of the blade portion 20a toward the base end side in the axial direction. A plurality of outer peripheral blades 24 are provided on the outer periphery of the blade portion 20a at intervals in the circumferential direction. In the present embodiment, two outer peripheral blades 24 are provided on the outer periphery of the blade portion 20a at equal pitch or unequal pitch in the circumferential direction. That is, the solid end mill 20 of this embodiment is a two-flute end mill.

[Outer peripheral convex part]
As shown in FIGS. 17, 19, 20, and 21, the outer peripheral convex portion 25 is opposite to the intermediate portion of the outer peripheral flank surface 23 located between both ends in the circumferential direction, that is, the end portion in the tool rotation direction T. It is placed in the middle part located between the end in the tool rotation direction. The outer peripheral convex portion 25 is arranged at least in the anti-tool rotation direction of the portion of the outer peripheral blade 24 used for cutting (the portion other than the base end portion of the blade portion 20a in the present embodiment). That is, the outer peripheral convex portion 25 is located in the anti-tool rotation direction of the outer peripheral blade 24.

A plurality of outer peripheral convex portions 25 are provided on the outer peripheral escape surface 23. The plurality of outer peripheral convex portions 25 may be arranged at intervals from each other, or may be partially connected to each other. In the illustrated example, the plurality of outer peripheral protrusions 25 are arranged at intervals from each other. In the example of this embodiment, each outer peripheral convex portion 25 has a protrusion shape. Specifically, the outer peripheral convex portion 25 has a polygonal shape, a circular shape, or the like when the outer peripheral escape surface 23 is viewed from the front (viewed from the outside in the radial direction), and is a quadrangular shape in the illustrated example. Each outer peripheral convex portion 25 is arranged at a distance from the outer peripheral blade 24 in the circumferential direction.

As shown in FIG. 19, the outer peripheral convex portion 25 has a top surface 25a, a front surface 25b, and a rear surface 25c.
The top surface 25a faces radially outward. The amount of protrusion of the top surface 25a from the outer peripheral flank 23 increases toward the direction of rotation of the anti-tool. In the example of this embodiment, the top surface 25a and the virtual circle VC are parallel to each other in a cross-sectional view perpendicular to the axis O shown in FIG. That is, the position of the top surface 25a in the radial direction is constant over the entire length in the circumferential direction in this cross-sectional view.

In the example of this embodiment, the top surface 25a extends in a convex curve shape in the circumferential direction around the axis O, that is, parallel to the machined surface MS of the work material in the cross-sectional view shown in FIG. The top surface 25a may have a linear shape extending substantially parallel to the machined surface MS of the work material in this cross-sectional view.

As shown in FIG. 19, among the plurality of outer peripheral convex portions 25, the end portion in the tool rotation direction T on the top surface 25a of the outer peripheral convex portion 25 arranged closest to the outer peripheral blade 24, and the outer peripheral blade 24. The distance _lt along the circumferential direction between them is 0.3 mm or more. The distance _lt is 1.35 mm or less. The length of the top surface 25a in the circumferential direction is, for example, 0.03 mm or more and 2 mm or less. The radial height h between the end of the top surface 25a in the tool rotation direction T and the portion of the outer peripheral relief surface 23 connected to the front surface 25b is, for example, 0.002 mm or more and 0.1 mm or less. .. The height h may be, for example, 0.05 mm or less.

The front surface 25b faces the tool rotation direction T and connects the top surface 25a and the outer peripheral relief surface 23. The front surface 25b is inclined toward the tool rotation direction T as it goes inward in the radial direction. In the example of this embodiment, the front surface 25b is linear in a cross-sectional view perpendicular to the axis O shown in FIG.

Although not particularly shown, the smaller angle (corresponding to the angle θ1 in FIG. 5) among the two angles (obtuse angle and superior angle) formed between the top surface 25a and the front surface 25b in the cross-sectional view perpendicular to the axis O. Is an obtuse angle. That is, the angle is larger than 90 °. The angle is 150 ° or less.
Further, in this cross-sectional view, of the two angles (obtuse angle and dominant angle) formed between the front surface 25b and the outer peripheral flank surface 23, the smaller angle (corresponding to the angle θ2 in FIG. 5) is the obtuse angle. That is, the angle is larger than 90 °. The angle is 143 ° or less.

The rear surface 25c faces the counter-tool rotation direction, and connects the top surface 25a and the outer peripheral relief surface 23. The rear surface 25c is inclined toward the counter-tool rotation direction as it goes inward in the radial direction. In the example of this embodiment, the rear surface 25c is linear in a cross-sectional view perpendicular to the axis O shown in FIG.

As shown in FIGS. 17, 19, 20, and 21, the plurality of outer peripheral convex portions 25 include a first outer peripheral convex portion (first convex portion) 25A and a second outer peripheral convex portion (second convex portion) 25B. And have.
The first outer peripheral convex portion 25A is the outer peripheral convex portion 25 arranged closest to the outer peripheral blade 24 among the plurality of outer peripheral convex portions 25. The second outer peripheral convex portion 25B is located in the anti-tool rotation direction with respect to the first outer peripheral convex portion 25A. In the example of the present embodiment, the second outer peripheral convex portion 25B is the outer peripheral convex portion 25 arranged at the farthest distance from the outer peripheral blade 24 among the plurality of outer peripheral convex portions 25. The amount of protrusion of the second outer peripheral convex portion 25B from the outer peripheral escape surface 23 is larger than the amount of protrusion of the first outer peripheral convex portion 25A from the outer peripheral escape surface 23.

A plurality of first outer peripheral convex portions 25A are provided at intervals in the blade length direction in which the outer peripheral blade 24 extends. In the example of the present embodiment, the plurality of first outer peripheral convex portions 25A are arranged at intervals in the axial direction. Each first outer peripheral convex portion 25A has a rib shape extending in the blade length direction of the outer peripheral blade 24. A plurality of second outer peripheral convex portions 25B are provided at intervals in the blade length direction in which the outer peripheral blade 24 extends. In the example of the present embodiment, the plurality of second outer peripheral convex portions 25B are arranged at intervals in the axial direction. Each second outer peripheral convex portion 25B has a rib shape extending in the blade length direction of the outer peripheral blade 24. The first outer peripheral convex portion 25A and the second outer peripheral convex portion 25B are alternately arranged in the blade length direction of the outer peripheral blade 24.

The lengths of the outer peripheral blades 24 of the first outer peripheral convex portion 25A and the second outer peripheral convex portion 25B along the blade length direction are, for example, 0.050 mm or more and 1.000 mm or less, respectively. The distance (interval) between the first outer peripheral convex portions 25A and 25A adjacent to each other in the blade length direction of the outer peripheral blade 24 and the distance between the second outer peripheral convex portions 25B and 25B adjacent to each other in the blade length direction of the outer peripheral blade 24 are respectively. For example, it is 0.050 mm or more and 1.000 mm or less.

In the example of the present embodiment, as shown in FIG. 21, the length in the direction orthogonal to the blade length direction of the outer peripheral blade 24 of the first outer peripheral convex portion 25A when viewed from the radial direction (when the outer peripheral relief surface 23 is viewed from the front). The diameter (width) and the length of the outer peripheral blade 24 of the second outer peripheral convex portion 25B in the direction orthogonal to the blade length direction are substantially the same as each other. Further, the length of the first outer peripheral convex portion 25A in the circumferential direction (tool rotation direction T) and the length of the second outer peripheral convex portion 25B in the circumferential direction are substantially the same. Further, the length of the first outer peripheral convex portion 25A in the axial direction (Z-axis direction) and the length of the second outer peripheral convex portion 25B in the axial direction are substantially the same. Further, the first outer peripheral convex portion 25A and the second outer peripheral convex portion 25B are arranged apart from each other in a direction orthogonal to the blade length direction of the outer peripheral blade 24. That is, the first outer peripheral convex portion 25A and the second outer peripheral convex portion 25B do not overlap each other when viewed from the blade length direction of the outer peripheral blade 24. When viewed from the blade length direction of the outer peripheral blade 24, the first outer peripheral convex portion 25A and the second outer peripheral convex portion 25B may partially overlap each other.

In the example of the present embodiment, as shown in FIG. 21, the axial position of the first outer peripheral convex portion 25A and the axial position of the second outer peripheral convex portion 25B are different from each other. That is, in the axial direction, the first outer peripheral convex portion 25A and the second outer peripheral convex portion 25B are arranged at different positions from each other.
In the present embodiment, the length of the top surface 25a of the first outer peripheral convex portion 25A and the length of the top surface 25a of the second outer peripheral convex portion 25B are obtained in each of the direction orthogonal to the blade length direction of the outer peripheral blade 24 and the circumferential direction. However, they are the same as each other. The length of the top surface 25a of the first outer peripheral convex portion 25A is longer than the length of the top surface 25a of the second outer peripheral convex portion 25B in each of the direction orthogonal to the blade length direction of the outer peripheral blade 24 and the circumferential direction. May be good. Further, the length of the top surface 25a of the first outer peripheral convex portion 25A is shorter than the length of the top surface 25a of the second outer peripheral convex portion 25B in each of the direction orthogonal to the blade length direction of the outer peripheral blade 24 and the circumferential direction. May be good.

In this embodiment, an example is given in which a plurality of outer peripheral convex portions 25 have a first outer peripheral convex portion 25A and a second outer peripheral convex portion 25B, but the present invention is not limited to this. For example, the plurality of outer peripheral convex portions 25 may have a third outer peripheral convex portion (third convex portion) located in the anti-tool rotation direction with respect to the second outer peripheral convex portion 25B. Further, the plurality of outer peripheral convex portions 25 may have a fourth outer peripheral convex portion (fourth convex portion) located in the anti-tool rotation direction with respect to the third outer peripheral convex portion. A plurality of third outer peripheral convex portions and fourth outer peripheral convex portions are provided on the outer peripheral escape surface 23, respectively. The amount of protrusion of the third outer peripheral convex portion 25B from the outer peripheral escape surface 23 is larger than the amount of protrusion of the second outer peripheral convex portion 25B from the outer peripheral escape surface 23. Further, the amount of protrusion of the fourth outer peripheral convex portion from the outer peripheral escape surface 23 is larger than the amount of protrusion of the third outer peripheral convex portion from the outer peripheral escape surface 23. Further, the plurality of outer peripheral convex portions 25 may have a fifth outer peripheral convex portion (fifth convex portion), a sixth outer peripheral convex portion (sixth convex portion), ..., As described above.

[Tip rake surface]
As shown in FIGS. 17 and 22, the tip rake face 26 is arranged at the tip of the wall surface 21b facing the tool rotation direction T in the groove wall of the chip discharge groove 21. The tip rake face 26 is arranged on a portion of the wall surface 21b of the chip discharge groove 21 facing the tool rotation direction T, which is adjacent to the tip blade 28. That is, the tip rake face 26 faces the tool rotation direction T. The tip rake face 26 extends along the tip blade 28. The tip rake face 26 has, for example, a concave curved surface.

[Tip flank]
The tip flank surface 27 is arranged on a portion of the tip surface of the blade portion 20a adjacent to the tip blade 28. The tip flank surface 27 is arranged adjacent to the tip blade 28 in the counter-tool rotation direction of the tip blade 28. The tip flank 27 faces the tip side in the axial direction. The tip flank 27 extends along the tip blade 28. The tip flank surface 27 is inclined toward the base end side in the axial direction from the tip blade 28 toward the counter tool rotation direction.

In FIG. 22, in the present embodiment, the virtual plane on which the tip blade 28 is located perpendicular to the axis O is defined as the machining reference plane VS. The machining reference surface VS corresponds to the machining surface MS of the work material. As shown in FIG. 22, two angles formed between the tip flank surface 27 and the machining reference surface VS when viewed from the radial direction orthogonal to the axis O (when viewed from the blade length direction in which the tip blade 28 extends). Of (acute angles and dominant angles), the smaller angle (that is, the acute angle) corresponds to the clearance angle γn. It can be said that the clearance angle γn is an angle formed between the tip flank surface 27 and the machined surface MS centering on the tip blade 28 in the side view of the solid end mill 20.
Each angle and each dimension shown in FIG. 22 corresponds to each angle and each dimension in the cross section perpendicular to the blade length direction in which the tip blade 28 extends. That is, the side view shown in FIG. 22 corresponds to a cross-sectional view perpendicular to the blade length direction of the tip blade 28.

What is indicated by the reference numeral VBmax in FIG. 22 is the maximum wear width of the tip flank 27 along the circumferential direction (along the machined surface MS of the work material). In the solid end mill 20, when the wear width of the tip flank 27 along the circumferential direction reaches the maximum wear width VBmax, it becomes difficult to maintain good cutting accuracy, and it is determined that the tool life is reached. In FIG. 22, the machined surface MS of the work material is located on the machined surface MS'on the base end side of the machined surface MS when the tip flank surface 27 reaches the maximum wear width VBmax.

[Tip blade]
As shown in FIGS. 17 and 18, the tip blade (bottom blade) 28 is arranged on the tip surface of the blade portion 20a. The tip blade 28 is located at the tip of the blade portion 20a in the axial direction. The tip blade 28 extends along the tip edge of the wall surface 21b of the chip discharge groove 21 facing the tool rotation direction T. The tip blade 28 extends radially. A plurality of tip blades 28 are provided at the tip of the blade portion 20a at intervals in the circumferential direction. In this embodiment, two tip blades 28 are provided at the tip of the blade portion 20a at equal pitch or unequal pitch in the circumferential direction.

[Convex tip]
As shown in FIGS. 17, 18 and 22, the tip convex portion 29 is an intermediate portion of the tip flank 27 located between both ends in the circumferential direction, that is, the end portion in the tool rotation direction T and the anti-tool rotation direction. It is placed in the middle part located between the end of the. The tip convex portion 29 is arranged at least in the anti-tool rotation direction of the portion of the tip blade 28 used for cutting. That is, the tip convex portion 29 is located in the anti-tool rotation direction of the tip blade 28.

A plurality of tip convex portions 29 are provided on the tip flank surface 27. The plurality of tip convex portions 29 may be arranged at intervals from each other, or may be partially connected to each other. In the illustrated example, the plurality of tip protrusions 29 are arranged at intervals from each other. In the example of the present embodiment, each tip convex portion 29 is rib-shaped and extends in a direction intersecting the blade length direction of the tip blade 28 (in the illustrated example, a direction orthogonal to the blade length direction). Each tip convex portion 29 is arranged at a distance from the tip blade 28 in the circumferential direction.

As shown in FIG. 22, the tip convex portion 29 has a top surface 29a, a front surface 29b, and a rear surface 29c.
The top surface 29a faces the tip side in the axial direction. The amount of protrusion of the top surface 29a from the tip flank surface 27 increases toward the counter-tool rotation direction. In the example of this embodiment, the top surface 29a and the processing reference surface VS are parallel to each other in the side view shown in FIG. That is, the position of the top surface 29a in the axial direction is constant over the entire length in the circumferential direction in this side view.

In the example of this embodiment, the top surface 29a spreads in a plane in parallel with the machined surface MS (machining reference surface VS) of the work material. The top surface 29a may have a convex curved surface shape that is convex toward the tip end side in the axial direction.

As shown in FIG. 22, among the plurality of tip convex portions 29, the end portion in the tool rotation direction T on the top surface 29a of the tip convex portion 29 arranged closest to the tip blade 28, and the tip blade 28. The distance _lt along the circumferential direction between them is 0.3 mm or more. The distance _lt is 1.35 mm or less. The length of the top surface 29a in the circumferential direction is, for example, 0.03 mm or more and 2 mm or less. The axial height h between the end of the top surface 29a in the tool rotation direction T and the portion of the tip flank 27 connected to the front surface 29b is, for example, 0.002 mm or more and 0.1 mm or less. .. The height h may be, for example, 0.05 mm or less.

The front surface 29b faces the tool rotation direction T and connects the top surface 29a and the tip flank surface 27. The front surface 29b is inclined toward the tool rotation direction T toward the base end side in the axial direction. In the example of this embodiment, the front surface 29b is planar.

In the side view shown in FIG. 22, of the two angles (obtuse angle and dominant angle) formed between the top surface 29a and the front surface 29b, the smaller angle θ1 is an obtuse angle. That is, the angle θ1 is larger than 90 °. The angle θ1 is 150 ° or less.
Further, in this side view, of the two angles (obtuse angle and dominant angle) formed between the front surface 29b and the tip flank surface 27, the smaller angle θ2 is an obtuse angle. That is, the angle θ2 is larger than 90 °. The angle θ2 is 143 ° or less.

The rear surface 29c faces the counter-tool rotation direction, and connects the top surface 29a and the tip flank surface 27. The rear surface 29c is inclined toward the counter-tool rotation direction toward the proximal end side in the axial direction. In the example of this embodiment, the rear surface 29c is planar.

As shown in FIGS. 17, 18 and 22, the plurality of tip convex portions 29 include a first tip convex portion (first convex portion) 29A and a second tip convex portion (second convex portion) 29B. Have.
The first tip convex portion 29A is a tip convex portion 29 arranged closest to the tip blade 28 among the plurality of tip convex portions 29. The second tip convex portion 29B is located in the anti-tool rotation direction with respect to the first tip convex portion 29A. In the example of the present embodiment, the second tip convex portion 29B is the tip convex portion 29 which is arranged farthest from the tip blade 28 among the plurality of tip convex portions 29. The amount of protrusion of the second tip convex portion 29B from the tip flank surface 27 is larger than the amount of protrusion of the first tip convex portion 29A from the tip flank surface 27.

A plurality of first tip convex portions 29A are provided at intervals in the blade length direction in which the tip blade 28 extends. In the example of this embodiment, the plurality of first tip convex portions 29A are arranged at intervals in the radial direction. Each first tip convex portion 29A has a rib shape extending in a direction intersecting the blade length direction of the tip blade 28 (direction orthogonal to the illustrated example). A plurality of second tip convex portions 29B are provided at intervals in the blade length direction in which the tip blade 28 extends. In the example of this embodiment, the plurality of second tip convex portions 29B are arranged at intervals in the radial direction. Each second tip convex portion 29B has a rib shape extending in a direction intersecting the blade length direction of the tip blade 28 (direction orthogonal to the illustrated example). The first tip convex portion 29A and the second tip convex portion 29B are alternately arranged in the blade length direction of the tip blade 28.

The length (width) of the tip blade 28 of the first tip convex portion 29A and the second tip convex portion 29B along the blade length direction is, for example, 0.050 mm or more and 1.000 mm or less, respectively. The distance (interval) between the first tip convex portions 29A and 29A adjacent to each other in the blade length direction of the tip blade 28 and the distance between the second tip convex portions 29B and 29B adjacent to each other in the blade length direction of the tip blade 28 are respectively. For example, it is 0.050 mm or more and 1.000 mm or less.

In the example of the present embodiment, the direction orthogonal to the blade length direction of the tip blade 28 of the second tip convex portion 29B is compared with the length in the direction orthogonal to the blade length direction of the tip blade 28 of the first tip convex portion 29A. The length of is large. In the side view shown in FIG. 22, the end portion of the first tip convex portion 29A in the anti-tool rotation direction and the end portion of the second tip convex portion 29B in the tool rotation direction T overlap each other. In this side view, the first tip convex portion 29A and the second tip convex portion 29B do not have to overlap each other.
In the present embodiment, the length of the top surface 29a of the first tip convex portion 29A and the length of the top surface 29a of the second tip convex portion 29B are the same in the direction orthogonal to the blade length direction of the tip blade 28. be. The length of the top surface 29a of the first tip convex portion 29A may be longer than the length of the top surface 29a of the second tip convex portion 29B in the direction orthogonal to the blade length direction of the tip blade 28. Further, the length of the top surface 29a of the first tip convex portion 29A may be shorter than the length of the top surface 29a of the second tip convex portion 29B in the direction orthogonal to the blade length direction of the tip blade 28.

In this embodiment, an example is given in which a plurality of tip convex portions 29 have a first tip convex portion 29A and a second tip convex portion 29B, but the present invention is not limited to this. For example, the plurality of tip convex portions 29 may have a third tip convex portion (third convex portion) located in the anti-tool rotation direction with respect to the second tip convex portion 29B. Further, the plurality of tip convex portions 29 may have a fourth tip convex portion (fourth convex portion) located in the anti-tool rotation direction with respect to the third tip convex portion. A plurality of third tip convex portions and fourth tip convex portions are provided on the tip flank surface 27, respectively. The amount of protrusion of the third tip convex portion from the tip flank surface 27 is larger than the amount of protrusion of the second tip convex portion 29B from the tip flank surface 27. Further, the amount of protrusion of the fourth tip convex portion from the tip flank surface 27 is larger than the amount of protrusion of the third tip convex portion from the tip flank surface 27. Further, the plurality of tip convex portions 29 may have a fifth tip convex portion (fifth convex portion), a sixth tip convex portion (sixth convex portion), ..., As described above.

[Cutting method]
Next, a cutting method for cutting the machined surface MS of the work material by the solid end mill (cutting tool) 20 of the present embodiment will be described.
As shown in FIGS. 19 and 20, in a cross-sectional view perpendicular to the axis O, a clearance angle formed between the tangent line passing over the outer peripheral blade 24 of the virtual circle VC (machined surface MS) and the outer peripheral flank 23. Is γn, and the maximum wear width of the outer peripheral flank 23 along the circumferential direction is VBmax. In the cutting method of the present embodiment, the distance H between the virtual circle VC and each outer peripheral convex portion 25 in the radial direction is VBmax · tanγn or more. Further, the top surface 25a of the outer peripheral convex portion 25 is parallel to the machined surface MS.
In the present embodiment, the distance H shown in FIG. 19 and the distance H shown in FIG. 20 having different positions in the axial direction are the same as each other.

As shown in FIG. 22, when viewed from the radial direction orthogonal to the axis O, the clearance angle formed between the tip flank 27 and the machining reference plane VS (machining surface MS) is γn, and the tip along the circumferential direction is defined as γn. The maximum wear width of the flank 27 is VBmax. In the cutting method of the present embodiment, the distance H between the machining reference surface VS and each tip convex portion 29 in the axial direction is VBmax · tanγn or more. Further, the top surface 29a of the tip convex portion 29 is parallel to the machined surface MS.

[Action and effect of this embodiment]
According to the solid end mill (cutting tool) 20 of the present embodiment described above, when cutting using the outer peripheral blade 24, the outer peripheral convex portion 25 protruding from the outer peripheral relief surface 23 is provided, so that, for example, a low cutting speed condition is provided. During cutting (milling) such as, a process damping phenomenon occurs and chatter vibration is suppressed. Further, in the case of cutting using the tip blade 28, since the tip convex portion 29 protruding from the tip flank 27 is provided, a process damping phenomenon occurs during cutting such as low cutting speed conditions, and chatter vibration occurs. Is suppressed.
That is, in the present embodiment, by providing the convex portions 25 and 29 on the flanks 23 and 27, the convex portions 25 and 29 can easily come into contact with the machined surface MS of the work material, so that the process damping phenomenon is positively promoted. It can be expressed as a target, and chatter vibration can be suppressed.

Further, in the present embodiment, since a plurality of outer peripheral convex portions 25 are provided on the outer peripheral escape surface 23, the distance and shape of each outer peripheral convex portion 25 from the outer peripheral blade 24, the amount of protrusion from the outer peripheral escape surface 23, and the length in the circumferential direction. By appropriately setting the length in the axial direction, the length in the blade length direction, etc., the vibration wavelength region in which the process damping effect is exhibited can be made different for each outer peripheral convex portion 25, thereby causing chatter vibration. The suppressable frequency range can be extended.
Further, since a plurality of tip convex portions 29 are provided on the tip flank surface 27, the distance and shape of each tip convex portion 29 from the tip blade 28, the amount of protrusion from the tip flank surface 27, the length in the circumferential direction, and the radial direction. By appropriately setting the length, the length in the blade length direction, etc., the vibration wavelength region in which the process damping effect is exhibited can be made different for each tip convex portion 29, thereby suppressing chatter vibration. The range can be expanded.
Therefore, according to the present embodiment, it is possible to suppress chatter vibration in a wide frequency band. That is, according to this embodiment, chatter vibration can be stably suppressed.

Further, in the present embodiment, the plurality of outer peripheral convex portions 25 include a first outer peripheral convex portion 25A and a second outer peripheral convex portion 25B having different distances from the outer peripheral blade 24 in the circumferential direction. Therefore, the frequency range in which the first outer peripheral convex portion 25A exhibits the process damping effect and the frequency range in which the second outer peripheral convex portion 25B exhibits the process damping effect can be made different from each other, and a wide frequency band can be obtained. In, the process damping effect can be exerted in a robust manner.
Further, the plurality of tip convex portions 29 include a first tip convex portion 29A and a second tip convex portion 29B having different distances from the tip blade 28 in the circumferential direction. Therefore, the frequency range in which the first tip convex portion 29A exhibits the process damping effect and the frequency range in which the second tip convex portion 29B exhibits the process damping effect can be made different from each other, and a wide frequency band can be obtained. In, the process damping effect can be exerted in a robust manner.

Further, in the present embodiment, the amount of protrusion of the second outer peripheral convex portion 25B from the outer peripheral escape surface 23 is larger than the amount of protrusion of the first outer peripheral convex portion 25A from the outer peripheral escape surface 23. That is, among the plurality of outer peripheral convex portions 25, the outer peripheral convex portion 25 that is farther from the outer peripheral blade 24 in the circumferential direction, the larger the amount of protrusion from the outer peripheral escape surface 23.
In this case, when cutting using the outer peripheral blade 24, the radial distance between the machined surface MS of the work material and the first outer peripheral convex portion 25A, and the machined surface MS of the work material and the second outer peripheral convex portion 25A. The difference from the radial distance from the portion 25B can be reduced, or each distance can be made the same. As a result, when chatter vibration occurs during cutting, each outer peripheral convex portion 25 can be stably brought into contact with the machined surface MS. The process damping phenomenon is stably expressed, and chatter vibration is stably suppressed.

Further, in the present embodiment, the amount of protrusion of the second tip convex portion 29B from the tip flank surface 27 is larger than the amount of protrusion of the first tip convex portion 29A from the tip flank surface 27. That is, among the plurality of tip convex portions 29, the tip convex portion 29 that is farther from the tip blade 28 in the circumferential direction has a larger amount of protrusion from the tip flank surface 27.
In this case, when cutting using the tip blade 28, the axial distance between the machined surface MS (corresponding to the machining reference surface VS) of the work material and the first tip convex portion 29A, and the work material The difference in the axial distance between the machined surface MS and the second tip convex portion 29B can be reduced, or the distances can be made the same. As a result, when chatter vibration occurs during cutting, each tip convex portion 29 can be stably brought into contact with the machined surface MS. The process damping phenomenon is stably expressed, and chatter vibration is stably suppressed.

Further, in the present embodiment, since the plurality of first outer peripheral convex portions 25A are arranged at intervals in the blade length direction of the outer peripheral blade 24, welding may occur between the outer peripheral blade 24 and the first outer peripheral convex portion 25A. , It is possible to prevent the outer peripheral blade 24 from being damaged by welding. Further, since the first outer peripheral convex portion 25A and the second outer peripheral convex portion 25B are alternately arranged in the blade length direction of the outer peripheral blade 24, the region where the outer peripheral convex portion 25 is not arranged can be suppressed to a small size in this blade length direction. In other words, in the blade length direction of the outer peripheral blade 24, the process damping effect due to the outer peripheral convex portion 25 is exhibited in a wide range, and chatter vibration is suppressed more stably.

Further, in the present embodiment, since the plurality of first tip convex portions 29A are arranged at intervals in the blade length direction of the tip blade 28, welding may occur between the tip blade 28 and the first tip convex portion 29A. , It is possible to prevent the tip blade 28 from being damaged by welding. Further, since the first tip convex portion 29A and the second tip convex portion 29B are alternately arranged in the blade length direction of the tip blade 28, the region where the tip convex portion 29 is not arranged can be suppressed to a small size in this blade length direction. In other words, the process damping effect of the tip convex portion 29 is exhibited in a wide range in the blade length direction of the tip blade 28, and chatter vibration is suppressed more stably.

Further, in the present embodiment, the first tip convex portion 29A and the second tip convex portion 29B each extend in a direction intersecting (orthogonal direction) with the blade length direction of the tip blade 28, so that the first tip convex portion 29A is a process. The vibration wavelength region in which the damping effect is exhibited and the vibration wavelength region in which the second tip convex portion 29B exhibits the process damping effect can be expanded, respectively, and chatter vibration is stably suppressed.

Further, in the present embodiment, the amount of protrusion of the top surface 25a of each outer peripheral convex portion 25 from the outer peripheral relief surface 23 increases toward the counter-tool rotation direction, that is, the top surface 25a with respect to the outer peripheral relief surface 23. It is tilted. Therefore, in a cross-sectional view perpendicular to the axis O shown in FIGS. 19 and 20, the top surface 25a of the outer peripheral convex portion 25 with respect to the machined surface MS is larger than the clearance angle γn of the outer peripheral relief surface 23 with respect to the machined surface MS of the work material. The inclination (angle corresponding to the clearance angle of the top surface 25a) can be reduced, and when chatter vibration occurs during cutting, the top surface 25a can be stably brought into contact with the machined surface MS. As a result, the process damping phenomenon is stably expressed, and chatter vibration is stably suppressed.

Further, in the present embodiment, the amount of protrusion of the top surface 29a of each tip convex portion 29 from the tip flank surface 27 increases toward the counter-tool rotation direction, that is, the top surface 29a with respect to the tip flank surface 27. It is tilted. Therefore, when viewed from the radial direction shown in FIG. 22, the inclination of the top surface 29a of the tip convex portion 29 with respect to the machined surface MS is larger than the clearance angle γn of the tip flank 27 with respect to the machined surface MS of the work material. The angle corresponding to the clearance angle of the top surface 29a) can be reduced, and when chatter vibration occurs during cutting, the top surface 29a can be stably brought into contact with the machined surface MS. As a result, the process damping phenomenon is stably expressed, and chatter vibration is stably suppressed.

Further, in the present embodiment, the front surface 25b of the outer peripheral convex portion 25 is inclined toward the tool rotation direction T toward the inner side in the radial direction, and the top is viewed in a cross section perpendicular to the axis O shown in FIGS. 19 and 20. Since the angle formed between the surface 25a and the front surface 25b (the angle corresponding to the angle θ1 in FIG. 22; hereinafter referred to as the angle θ1) is an obtuse angle, the connection portion between the top surface 25a and the front surface 25b and the outer peripheral escape Adhesion of the work material is suppressed from adhering to or accumulating on the connection portion between the surface 23 and the front surface 25b. As a result, the deposition of adhered matter on the outer peripheral convex portion 25 and the outer peripheral escape surface 23 is suppressed, and the cutting edge defect of the outer peripheral blade 24 is suppressed. Further, since the front surface 25b is inclined, it is possible to prevent the machined surface MS from being cut when the outer peripheral convex portion 25 comes into contact with the machined surface MS, and the machined surface accuracy is ensured.

Further, in the present embodiment, since the angle θ1 formed between the top surface 25a and the front surface 25b is 150 ° or less in the cross-sectional view perpendicular to the axis O, the front surface 25b is abbreviated as the machined surface MS of the work material. It is suppressed that they are arranged in parallel. As a result, when chatter vibration occurs during cutting, it is possible to prevent the front surface 25b of the outer peripheral convex portion 25 from coming into contact with the machined surface MS of the work material. Since the top surface 25a of the outer peripheral convex portion 25 is stably brought into contact with the machined surface MS, chatter vibration in a desired frequency band can be stably suppressed.

Further, in the present embodiment, an angle formed between the front surface 25b of the outer peripheral convex portion 25 and the outer peripheral escape surface 23 (an angle corresponding to the angle θ2 in FIG. 22; hereinafter, an angle θ2) in a cross-sectional view perpendicular to the axis O. Since the angle is blunt, it is possible to prevent the adherents of the work material from adhering to or accumulating at the connection portion between the front surface 25b and the outer peripheral flank 23. As a result, the deposition of adhered matter on the outer peripheral convex portion 25 and the outer peripheral escape surface 23 is suppressed, and the cutting edge defect of the outer peripheral blade 24 is suppressed.

Further, in the present embodiment, since the angle θ2 formed between the front surface 25b and the outer peripheral flank 23 is 143 ° or less in the cross-sectional view perpendicular to the axis O, the front surface 25b is the machined surface MS of the work material. It is suppressed that they are arranged substantially in parallel. As a result, when chatter vibration occurs during cutting, it is possible to prevent the front surface 25b of the outer peripheral convex portion 25 from coming into contact with the machined surface MS of the work material. Since the top surface 25a of the outer peripheral convex portion 25 is stably brought into contact with the machined surface MS, chatter vibration in a desired frequency band can be stably suppressed.

Further, in the present embodiment, among the plurality of outer peripheral convex portions 25, the end portion in the tool rotation direction T on the top surface 25a of the outer peripheral convex portion 25 (that is, the first outer peripheral convex portion 25A) arranged closest to the outer peripheral blade 24. Since the distance _lt in the circumferential direction between the outer peripheral blade 24 and the outer peripheral blade 24 is 0.3 mm or more, the outer peripheral convex portion 25 (first outer peripheral convex portion 25A) even if the flank wear progresses due to cutting. ) Is suppressed from being worn together with the outer peripheral flank surface 23. Therefore, the process damping phenomenon is stably exhibited by the outer peripheral convex portion 25, and the chatter vibration is stably suppressed. The function of the solid end mill 20 is maintained well for a long period of time, and the tool life is extended.
Further, since the outer peripheral convex portion 25 is arranged so as not to be too close to the outer peripheral blade 24, the process damping phenomenon can be exhibited while suppressing the contact resistance between the outer peripheral convex portion 25 and the machined surface MS of the work material to be small.

Further, in the present embodiment, since the distance _lt is 1.35 mm or less, it is possible to stably obtain the process damping action by the outer peripheral convex portion 25 with respect to the frequency band of chatter vibration generated during cutting. That is, the effect of the present invention can be obtained robustly over a wide frequency band. Further, regardless of the size of the clearance angle γn at the time of cutting, that is, even if the clearance angle γn is set to be large, the outer peripheral convex portion 25 can be stably brought into contact with the machined surface MS of the work material. The process damping phenomenon is stably exhibited by the outer peripheral convex portion 25, and chatter vibration is stably suppressed.

Further, in the present embodiment, since the length of the top surface 25a of the outer peripheral convex portion 25 in the circumferential direction is 2 mm or less, the contact area and contact area between the top surface 25a and the machined surface MS of the work material can be suppressed to a small size. .. Therefore, it is possible to suppress the frictional resistance in the tangential direction (cutting direction, that is, the circumferential direction) due to the contact between the outer peripheral convex portion 25 and the machined surface MS. In addition, it is possible to prevent the adhered material of the work material from adhering to the outer peripheral convex portion 25.

Further, in the present embodiment, the position of the top surface 25a in the radial direction is constant over the entire length in the circumferential direction in a cross-sectional view perpendicular to the axis O.
In this case, the top surface 25a of the outer peripheral convex portion 25 can be stably brought into contact with the machined surface MS of the work material. Therefore, chatter vibration is stably suppressed.

Although not particularly shown, the top surface 25a may extend inward in the radial direction in the direction of rotation of the anti-tool in a cross-sectional view perpendicular to the axis O.
In this case, the top surface 25a of the outer peripheral convex portion 25 is inclined so as to be separated from the machined surface MS of the work material in the radial direction toward the anti-tool rotation direction. The process damping phenomenon can be exhibited while suppressing the contact resistance between the top surface 25a of the outer peripheral convex portion 25 and the machined surface MS of the work material to be small, and chatter vibration can be stably suppressed.

Further, in the present embodiment, the front surface 29b of the tip convex portion 29 is inclined toward the tool rotation direction T toward the proximal end side in the axial direction, and is viewed from the side (tip blade) in the radial direction shown in FIG. Since the angle θ1 formed between the top surface 29a and the front surface 29b is an obtuse angle in the cross-sectional view perpendicular to the blade length direction of 28), the connection portion between the top surface 29a and the front surface 29b and the tip escape Adhesion of the work material is suppressed from adhering to or accumulating on the connection portion between the surface 27 and the front surface 29b. As a result, the deposition of adhered matter on the tip convex portion 29 and the tip flank 27 is suppressed, and the cutting edge defect of the tip blade 28 is suppressed. Further, since the front surface 29b is inclined, it is possible to prevent the machined surface MS from being cut when the tip convex portion 29 comes into contact with the machined surface MS, and the machined surface accuracy is ensured.

Further, in the present embodiment, since the angle θ1 formed between the top surface 29a and the front surface 29b is 150 ° or less in the side view seen from the radial direction, the front surface 29b is abbreviated as the machined surface MS of the work material. It is suppressed that they are arranged in parallel. As a result, when chatter vibration occurs during cutting, it is possible to prevent the front surface 29b of the tip convex portion 29 from coming into contact with the machined surface MS of the work material. Since the top surface 29a of the tip convex portion 29 is stably brought into contact with the machined surface MS, chatter vibration in a desired frequency band can be stably suppressed.

Further, in the present embodiment, since the angle θ2 formed between the front surface 29b of the tip convex portion 29 and the tip flank 27 is an obtuse angle when viewed from the side in the radial direction, the front surface 29b and the tip flank 27 Adhesion of the work material is suppressed from adhering to or accumulating on the connecting portion of the work material. As a result, the deposition of adhered matter on the tip convex portion 29 and the tip flank 27 is suppressed, and the cutting edge defect of the tip blade 28 is suppressed.

Further, in the present embodiment, since the angle θ2 formed between the front surface 29b and the tip flank 27 is 143 ° or less in the side view seen from the radial direction, the front surface 29b is the machined surface MS of the work material. It is suppressed that they are arranged substantially in parallel. As a result, when chatter vibration occurs during cutting, it is possible to prevent the front surface 29b of the tip convex portion 29 from coming into contact with the machined surface MS of the work material. Since the top surface 29a of the tip convex portion 29 is stably brought into contact with the machined surface MS, chatter vibration in a desired frequency band can be stably suppressed.

Further, in the present embodiment, among the plurality of tip convex portions 29, the end portion in the tool rotation direction T on the top surface 29a of the tip convex portion 29 (that is, the first tip convex portion 29A) arranged closest to the tip blade 28. Since the distance _lt in the circumferential direction between the tip blade 28 and the tip blade 28 is 0.3 mm or more, the tip convex portion 29 (first tip convex portion 29A) even if the flank wear progresses due to cutting. ) Is suppressed from being worn together with the tip flank surface 27. Therefore, the process damping phenomenon is stably exhibited by the tip convex portion 29, and the chatter vibration is stably suppressed. The function of the solid end mill 20 is maintained well for a long period of time, and the tool life is extended.
Further, since the tip convex portion 29 is arranged so as not to be too close to the tip blade 28, the process damping phenomenon can be exhibited while suppressing the contact resistance between the tip convex portion 29 and the machined surface MS of the work material to be small.

Further, in the present embodiment, since the distance _lt is 1.35 mm or less, the process damping action by the tip convex portion 29 can be stably obtained with respect to the frequency band of chatter vibration generated during cutting. That is, the effect of the present invention can be obtained robustly over a wide frequency band. Further, regardless of the size of the clearance angle γn during cutting, that is, even if the clearance angle γn is set large, the tip convex portion 29 can be stably brought into contact with the machined surface MS of the work material. The process damping phenomenon is stably exhibited by the tip convex portion 29, and chatter vibration is stably suppressed.

Further, in the present embodiment, since the length of the top surface 29a of the tip convex portion 29 in the circumferential direction is 2 mm or less, the contact area and contact area between the top surface 29a and the machined surface MS of the work material can be suppressed to a small size. .. Therefore, it is possible to suppress the frictional resistance in the tangential direction (cutting direction, that is, the circumferential direction) due to the contact between the tip convex portion 29 and the machined surface MS. In addition, it is possible to prevent the adhered material of the work material from adhering to the tip convex portion 29.

Further, in the present embodiment, the position of the top surface 29a in the axial direction is constant over the entire length in the circumferential direction when viewed from the side in the radial direction.
In this case, the top surface 29a of the tip convex portion 29 can be stably brought into contact with the machined surface MS of the work material. Therefore, chatter vibration is stably suppressed.

Although not particularly shown, the top surface 29a may extend toward the proximal end side in the axial direction in the side view from the radial direction toward the anti-tool rotation direction.
In this case, the top surface 29a of the tip convex portion 29 is inclined so as to be separated from the machined surface MS of the work material in the axial direction toward the anti-tool rotation direction. The process damping phenomenon can be exhibited while suppressing the contact resistance between the top surface 29a of the tip convex portion 29 and the machined surface MS of the work material to be small, and chatter vibration can be stably suppressed.

Further, according to the cutting method of the present embodiment, as shown in FIGS. 19 and 20, the radial distance H between the virtual circle VC (corresponding to the machined surface MS of the work material) and each outer peripheral convex portion 25. That is, the distance H, which is the retreat distance of each outer peripheral convex portion 25 with respect to the machined surface MS of the work material, is VBmax · tanγn or more. Therefore, chatter vibration can be stably suppressed by the plurality of outer peripheral convex portions 25 until the flank wear in the vicinity of the outer peripheral blade 24 of the solid end mill 20 becomes maximum and the tool life is reached.

Further, in the cutting method of the present embodiment, the top surface 25a of the outer peripheral convex portion 25 is parallel to the machined surface MS of the work material.
In this case, the top surface 25a can be stably brought into contact with the machined surface MS. Therefore, chatter vibration is stably suppressed.

Further, according to the cutting method of the present embodiment, as shown in FIG. 22, the axial distance H between the machining reference surface VS (corresponding to the machining surface MS of the work material) and each tip convex portion 29, that is, The distance H, which is the evacuation distance of each tip convex portion 29 with respect to the machined surface MS of the work material, is VBmax · tanγn or more. Therefore, chatter vibration can be stably suppressed by the plurality of tip convex portions 29 until the flank wear in the vicinity of the tip blade 28 of the solid end mill 20 becomes maximum and the tool life is reached.

Further, in the cutting method of the present embodiment, the top surface 29a of the tip convex portion 29 is parallel to the machined surface MS of the work material.
In this case, the top surface 29a can be stably brought into contact with the machined surface MS. Therefore, chatter vibration is stably suppressed.

[Other configurations included in the present invention]
The present invention is not limited to the above-described embodiment, and the configuration can be changed without departing from the spirit of the present invention, for example, as described below.

In the second embodiment, the configuration of the first modification of the first embodiment shown in FIGS. 9 and 10 may be adopted. In this case, the plurality of outer peripheral convex portions 25 have a plurality of first outer peripheral convex portions 25A arranged at intervals in the blade length direction in which the outer peripheral blade 24 extends. Each first outer peripheral convex portion 25A extends in a direction intersecting the blade length direction of the outer peripheral blade 24 (direction orthogonal to the illustrated example, and may be a circumferential direction). Further, the plurality of tip convex portions 29 have a plurality of first tip convex portions 29A arranged at intervals in the blade length direction in which the tip blade 28 extends. Each first tip convex portion 29A extends in a direction intersecting the blade length direction of the tip blade 28 (direction orthogonal to the illustrated example).
In this case, the same effect as that of the first modification can be obtained.

In the second embodiment, the configuration of the second modification of the first embodiment shown in FIGS. 11 and 12 may be adopted. In this case, the plurality of outer peripheral convex portions 25 have a first outer peripheral convex portion 25A, a second outer peripheral convex portion 25B, and a third outer peripheral convex portion. The first outer peripheral convex portion 25A, the second outer peripheral convex portion 25B, and the third outer peripheral convex portion each extend in the blade length direction of the outer peripheral blade 24. Further, the plurality of tip convex portions 29 have a first tip convex portion 29A, a second tip convex portion 29B, and a third tip convex portion. The first tip convex portion 29A, the second tip convex portion 29B, and the third tip convex portion each extend in the blade length direction of the tip blade 28.
In this case, the same effect as that of the second modification can be obtained.

In the second embodiment, the configuration of the third modification of the first embodiment shown in FIGS. 13 and 14 may be adopted. In this case, the plurality of outer peripheral convex portions 25 have a plurality of first outer peripheral convex portions 25A arranged at intervals in the blade length direction in which the outer peripheral blade 24 extends. Each of the first outer peripheral convex portions 25A extends in the blade length direction of the outer peripheral blade 24 in the direction orthogonal to the blade length direction of the outer peripheral blade 24. That is, each first outer peripheral convex portion 25A extends in a direction (oblique direction) in which the direction orthogonal to the blade length direction and the blade length direction are combined. Further, the plurality of tip convex portions 29 have a plurality of first tip convex portions 29A arranged at intervals in the blade length direction in which the tip blade 28 extends. Each first tip convex portion 29A extends in the blade length direction of the tip blade 28 in a direction orthogonal to the blade length direction of the tip blade 28. That is, each first tip convex portion 29A extends in a direction (oblique direction) in which the direction orthogonal to the blade length direction and the blade length direction are combined.
In this case, the same effect as that of the third modification can be obtained.

In the second embodiment, the configuration of the fourth modification of the first embodiment shown in FIGS. 15 and 16 may be adopted. In this case, the plurality of outer peripheral convex portions 25 have a first outer peripheral convex portion 25A and a second outer peripheral convex portion 25B. A plurality of first outer peripheral convex portions 25A are provided side by side in the blade length direction of the outer peripheral blade 24. The plurality of first outer peripheral convex portions 25A include one first outer peripheral convex portion 25A extending in a direction orthogonal to the blade length direction of the outer peripheral blade 24, a direction orthogonal to the blade length direction of the outer peripheral blade 24, and an outer peripheral blade 24. The other first outer peripheral convex portion 25A extending inclined with respect to the blade length direction is included. The second outer peripheral convex portion 25B extends in the blade length direction of the outer peripheral blade 24. The plurality of tip convex portions 29 have a first tip convex portion 29A and a second tip convex portion 29B. A plurality of first tip convex portions 29A are provided side by side in the blade length direction of the tip blade 28. The plurality of first tip convex portions 29A include one first tip convex portion 29A extending in a direction orthogonal to the blade length direction of the tip blade 28, a direction orthogonal to the blade length direction of the tip blade 28, and a tip blade 28. The other first tip convex portion 29A, which extends at an angle with respect to the blade length direction, is included. The second tip convex portion 29B extends in the blade length direction of the tip blade 28.
In this case, the same effect as that of the fourth modification can be obtained.

In the first embodiment and the second embodiment, the front surfaces 14b, 25b, 29b of the convex portions 14, 25, 29 have a concave curved surface portion (not shown) at the end portion connected to the flanks 12, 23, 27. May be good.
In this case, the front surfaces 14b, 25b, 29b and the flanks 12, 23, 27 are smoothly connected, and the adhesion or accumulation of the work material is suppressed from adhering to or accumulating on the connecting portion. As a result, deposits are suppressed from being deposited on the convex portions 14, 25, 29 and the flanks 12, 23, 27, and the cutting edge defects of the cutting edges 13, 24, 28 are suppressed.

In the first embodiment and the second embodiment, the front surfaces 14b, 25b, 29b of the convex portions 14, 25, 29 have a convex curved surface portion (not shown) at the end portion connected to the top surface 14a, 25a, 29a. May be good.
In this case, it is possible to prevent the formation of sharp corners at the connection portion between the front surface 14b, 25b, 29b and the top surface 14a, 25a, 29a. Therefore, even if the convex portions 14, 25, 29 come into contact with the machined surface MS of the work material during chatter vibration, the adherents of the work material adhere to the front surfaces 14b, 25b, 29b of the convex portions 14, 25, 29. It's hard to do. That is, since the deposits are suppressed on the convex portions 14, 25, 29 and the flanks 12, 23, 27, the cutting edge defects of the cutting edges 13, 24, 28 are suppressed. Further, since the convex portions 14, 25, and 29 are prevented from cutting the machined surface MS, the machined surface accuracy is ensured.

In the first embodiment and the second embodiment, the angles θ1 and θ2 do not have to be obtuse. That is, the angle θ1 may be 90 ° or less, and the angle θ2 may be 90 ° or less.

Further, in the above-described embodiment, the cutting tool with a replaceable cutting edge 10 and the solid end mill 20 have been described as examples, but the cutting tools are not limited thereto. For example, the present invention may be applied to a solid type cutting tool or a cutting edge exchange type end mill. Further, the present invention may be applied to a turning tool other than a cutting tool and a turning tool other than an end mill. Further, the present invention may be applied to cutting tools other than turning tools and turning tools.

In addition, each configuration described in the above-described embodiments and modifications may be combined, and the configurations may be added, omitted, replaced, or otherwise changed without departing from the spirit of the present invention. Further, the present invention is not limited to the above-described embodiments, but is limited only to the scope of claims.

According to the cutting tool and cutting method of the present invention, chatter vibration can be stably suppressed. Therefore, it has industrial applicability.

10 ... Cutting edge replaceable tool (cutting tool)
11 ... Scoop surface 12 ... Escape surface 13 ... Cutting edge 14 ... Convex part 14a, 25a, 29a ... Top surface 14b, 25b, 29b ... Front surface 14A ... First convex part 14B ... Second convex part 20 ... Solid end mill (cutting tool) )
22 ... Outer rake surface (rake surface)
23 ... Outer peripheral flank (flank)
24 ... Outer blade (cutting blade)
25 ... Outer peripheral convex part (convex part)
25A ... First outer peripheral convex portion (first convex portion)
25B ... Second outer peripheral convex portion (second convex portion)
26 ... Tip rake surface (rake surface)
27 ... Tip flank (flank)
28 ... Tip blade (cutting blade)
29 ... Tip convex part (convex part)
29A ... 1st tip convex part (1st convex part)
29B ... 2nd tip convex part (2nd convex part)
D1 ... 1st direction D2 ... 2nd direction D3 ... 3rd direction H ... Distance (evacuation distance)
l _t (l _ta , l _tb , l _ct ) ... Distance MS ... Machining surface O ... Tool axis T ... Tool rotation direction VBmax ... Maximum wear width VC ... Virtual circle VS ... Machining reference surface γn ... Clearance angle

Claims (19)

The rake face and
On the escape side,
A cutting edge formed on a ridgeline connecting the rake surface and the flank surface,
It comprises a protrusion that projects from the flank and is disposed away from the cutting edge.
A virtual plane including the blade length direction in which the cutting edge extends and a predetermined direction intersecting the cutting edge is used as a machining reference plane.
The direction orthogonal to the machining reference plane is set as the first direction.
The predetermined direction is set as the second direction.
The direction orthogonal to the first direction and the second direction is defined as the third direction.
Of the first directions, the direction from the cutting edge to the inside of the tool is defined as the inside of the first direction.
Of the second directions, the direction from the cutting edge to the convex portion is defined as the rear side of the second direction.
The flank is inclined inward in the first direction from the cutting edge toward the rear side in the second direction.
A plurality of the convex portions are provided on the flank.
Cutting tools. The plurality of the convex portions are
The first convex part and
It has a second convex portion located on the rear side in the second direction with respect to the first convex portion.
The cutting tool according to claim 1. The amount of protrusion of the second convex portion from the flank is larger than the amount of protrusion of the first convex portion from the flank.
The cutting tool according to claim 2. A plurality of the first convex portions are provided at intervals in the blade length direction.
A plurality of the second convex portions are provided at intervals in the blade length direction.
The first convex portion and the second convex portion are arranged alternately in the blade length direction.
The cutting tool according to claim 2 or 3. The first convex portion extends in the blade length direction and extends.
The second convex portion extends in the blade length direction.
The cutting tool according to claim 2 or 3. The plurality of the convex portions have a plurality of first convex portions arranged at intervals in the blade length direction.
Each of the first convex portions extends in the second direction.
The cutting tool according to claim 1. The plurality of the convex portions have a plurality of first convex portions arranged at intervals in the blade length direction.
Each of the first convex portions extends in a direction in which the blade length direction and the second direction are combined.
The cutting tool according to claim 1. Of the first directions, the direction from the cutting edge to the outside of the tool is defined as the outside of the first direction.
Of the second directions, the direction from the convex portion toward the cutting edge is defined as the front side in the second direction.
The convex part is
The top surface facing outward in the first direction and
It faces the front side in the second direction and has a front surface connecting the top surface and the flank surface.
The amount of protrusion of the top surface from the flank increases toward the rear side in the second direction.
The cutting tool according to any one of claims 1 to 7. It is a cutting method that cuts the machined surface of the work material with a cutting tool.
The cutting tool is
The rake face and
On the escape side,
A cutting edge formed on a ridgeline connecting the rake surface and the flank surface,
It comprises a protrusion that projects from the flank and is disposed away from the cutting edge.
A virtual plane including the blade length direction in which the cutting edge extends and the cutting direction intersecting the cutting edge is used as the machining reference plane.
The direction orthogonal to the machining reference plane is set as the first direction.
The cutting direction is the second direction.
The direction orthogonal to the first direction and the second direction is defined as the third direction.
Of the first directions, the direction from the cutting edge to the inside of the tool is defined as the inside of the first direction.
Of the second directions, the direction from the cutting edge to the convex portion is defined as the rear side of the second direction.
The flank is inclined inward in the first direction from the cutting edge toward the rear side in the second direction.
A plurality of the convex portions are provided on the flank surface, and the convex portions are provided.
In a cross-sectional view perpendicular to the third direction, the clearance angle formed between the flank and the machining reference plane is γn, and the maximum wear width of the flank along the second direction is VBmax.
In the first direction, the distance H between the processing reference surface and each of the convex portions is VBmax · tanγn or more.
Cutting method. A cutting tool that can be rotated in the circumferential direction around the tool axis.
Of the circumferential directions, the rake face facing the tool rotation direction and
On the escape side,
A cutting edge formed on a ridgeline connecting the rake surface and the flank surface,
It comprises a protrusion that projects from the flank and is disposed away from the cutting edge.
The flank is inclined inward in the radial direction perpendicular to the tool axis as it goes from the cutting edge toward the counter-tool rotation direction in the circumferential direction, or the tool axis extends in the axial direction. Inclined toward the base side,
A plurality of the convex portions are provided on the flank.
Cutting tools. The plurality of the convex portions are
The first convex part and
It has a second convex portion located in the anti-tool rotation direction with respect to the first convex portion.
The cutting tool according to claim 10. The amount of protrusion of the second convex portion from the flank is larger than the amount of protrusion of the first convex portion from the flank.
The cutting tool according to claim 11. A plurality of the first convex portions are provided at intervals in the blade length direction in which the cutting edge extends.
A plurality of the second convex portions are provided at intervals in the blade length direction.
The first convex portion and the second convex portion are arranged alternately in the blade length direction.
The cutting tool according to claim 11 or 12. The first convex portion extends in the blade length direction in which the cutting edge extends, and the first convex portion extends.
The second convex portion extends in the blade length direction.
The cutting tool according to claim 11 or 12. The plurality of the convex portions have a plurality of first convex portions arranged at intervals in the blade length direction in which the cutting edge extends.
Each of the first convex portions extends in a direction intersecting the blade length direction.
The cutting tool according to claim 10. The plurality of the convex portions have a plurality of first convex portions arranged at intervals in the blade length direction in which the cutting edge extends.
Each of the first convex portions extends in a direction orthogonal to the blade length direction and a combined direction of the blade length direction.
The cutting tool according to claim 10. The convex part is
With the top surface facing the outside in the radial direction in the radial direction or facing the tip side in the axial direction,
It has a front surface that faces the tool rotation direction and connects the top surface and the flank surface.
The amount of protrusion of the top surface from the flank increases toward the direction of rotation of the anti-tool.
The cutting tool according to any one of claims 10 to 16. It is a cutting method that cuts the machined surface of the work material with a cutting tool that is rotated in the circumferential direction around the tool axis.
The cutting tool is
Of the circumferential directions, the rake face facing the tool rotation direction and
Of the radial directions orthogonal to the tool axis, the flank facing the outside in the radial direction and
A cutting edge formed on a ridgeline connecting the rake surface and the flank surface,
It comprises a protrusion that projects from the flank and is disposed away from the cutting edge.
The flank is inclined inward in the radial direction from the cutting edge in the circumferential direction toward the counter tool rotation direction.
A plurality of the convex portions are provided on the flank surface, and the convex portions are provided.
In a cross-sectional view perpendicular to the tool axis, the clearance angle formed between the tangent of the virtual circle centered on the tool axis and passing over the cutting edge and the flank is defined as γn. The maximum wear width of the flank along the circumferential direction is VBmax.
In the radial direction, the distance H between the virtual circle and each of the convex portions is VBmax · tanγn or more.
Cutting method. It is a cutting method that cuts the machined surface of the work material with a cutting tool that is rotated in the circumferential direction around the tool axis.
The cutting tool is
Of the circumferential directions, the rake face facing the tool rotation direction and
Of the axial direction in which the tool axis extends, the flank facing the tip side and
A cutting edge formed on a ridgeline connecting the rake surface and the flank surface,
It comprises a protrusion that projects from the flank and is disposed away from the cutting edge.
The flank is inclined from the cutting edge toward the proximal end side in the axial direction in the circumferential direction toward the counter tool rotation direction.
A plurality of the convex portions are provided on the flank surface, and the convex portions are provided.
The virtual plane on which the cutting edge is located perpendicular to the tool axis is used as the machining reference plane.
When viewed from the radial direction orthogonal to the tool axis, the clearance angle formed between the flank and the machining reference plane is γn, and the maximum wear width of the flank along the circumferential direction is VBmax.
In the axial direction, the distance H between the processing reference surface and each of the convex portions is VBmax · tanγn or more.
Cutting method.

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