CN112789131A

CN112789131A - Rotary tool

Info

Publication number: CN112789131A
Application number: CN201980063940.6A
Authority: CN
Inventors: 山田恭也; 南彻; 神田保之
Original assignee: Jianfang Co ltd
Current assignee: Jianfang Co ltd; Kanefusa KK
Priority date: 2018-10-30
Filing date: 2019-10-08
Publication date: 2021-05-11
Also published as: WO2020090372A1; JPWO2020090372A1

Abstract

The invention provides a rotary tool with a high-performance chip breaker. The rotary tool has: a rotary tool body 10; and a cutting edge portion 20 having a cutting edge, which is made of polycrystalline diamond (PCD) or cubic boron nitride sintered Compact (CBN) and is provided to the rotary tool body 10, wherein a chip breaker is provided in the vicinity of the cutting edge on a rake face of the cutting edge portion 20, and the rotary tool has a structure of at least one of the following (i) and (ii). (i) The chip breaker is a recess having an R-shaped cross-sectional shape in a direction perpendicular to the cutting edge. (ii) The cutting edge is inclined with respect to the rotation axis of the rotary tool body 10, and the chip breaker is a depression which becomes continuously shallow as approaching the end in the outer peripheral direction and/or the axial direction of the rotary tool body 10 at both ends in the direction parallel to the cutting edge.

Description

Rotary tool

Technical Field

The present invention relates to a rotary tool.

Background

In some conventional rotary tools, a chip breaker is provided on a rake face of a blade portion in order to break chips short or reduce a curl diameter (patent documents 1 and 2). In the case of a chip breaker, chips are connected to each other to be long and get entangled in a tool, and there is a problem that automatic operation is hindered, a workpiece is damaged, or chips are accumulated at the edge by biting into the edge portion.

Patent document 1: japanese patent laid-open publication No. 2017-94467

Patent document 2: japanese patent No. 4185370

Disclosure of Invention

The present invention has been made in view of the above circumstances, and an object to be solved by the present invention is to provide a rotary tool including a high-performance chip breaker.

The present inventors have made intensive studies on the relationship between the shape of the chip breaker and the form of the chips, and as a result, have completed the following invention.

A rotary tool according to the present invention for solving the above problems includes: a rotary tool body; and a cutting edge portion formed of polycrystalline diamond (PCD) or cubic boron nitride sintered Compact (CBN) and provided on the rotary tool body, wherein a chip breaker is provided in the vicinity of the cutting edge on a rake face of the cutting edge portion, and the rotary tool has a structure including at least one of the following (i) and (ii).

(i) The chip breaker is a recess having an R-shaped cross-sectional shape in a direction perpendicular to the cutting edge.

(ii) The cutting edge is inclined with respect to a rotation axis of the rotary tool body, and the chip breaker is a recess that becomes continuously shallower as approaching an end in an outer peripheral direction and/or an axial direction of the rotary tool body at both ends in a direction parallel to the cutting edge.

In particular, the width of the chip breaker in a direction perpendicular to the cutting edge is preferably 0.15mm to 0.5 mm.

Preferably, the chip breaker is spaced from the cutting edge by 0.01mm to 0.05 mm.

Preferably, the chip breaker has a surface textured with projections and depressions. The value of the surface roughness Rz of the inner surface of the chip breaker is preferably 2.0 μm or less.

With the above configuration, the rotary tool of the present invention can cut chips generated during cutting in a short time. As a result, the chips can be prevented from being entangled with the rotary tool or the like, the chips can be prevented from damaging the workpiece surface, and the chips can be effectively prevented from being accumulated on the blade portion.

By making the cross-sectional shape (cross-section in the direction perpendicular to the cutting edge) of the chip breaker an R-shape, the curl diameter of the generated chips can be reduced. Further, since both end portions (the direction parallel to the cutting edge) of the chip breaker are formed in a shape that becomes continuously shallower as approaching the end portions in the outer peripheral direction and/or the axial direction of the rotary tool body, it is possible to suppress the generated chips from abutting against the inner surface of the end portions in the outer peripheral direction of the chip breaker and applying stress in the axial direction. When stress in the axial direction is suppressed from being applied to the chips, the tips of the curled chips are suppressed from being displaced in the axial direction and spirally connected, and the generated chips can be cut short. In particular, both end portions of the chip breaker are formed in a continuously shallow shape as they approach the end portions, and therefore, the effect of shortening chips can be expected.

Drawings

Fig. 1 is a perspective view showing a rotary tool (reamer) in embodiment 1.

Fig. 2 is an enlarged perspective view of a blade portion provided in the reamer according to embodiment 1.

Fig. 3 is an enlarged perspective view of a chip breaker provided in the blade portion of embodiment 1.

Fig. 4 is a diagrammatic section IV-IV of fig. 3.

Fig. 5 is a perspective view showing a modification of embodiment 1.

Fig. 6 is an enlarged perspective view of a chip breaker (pocket) provided in the blade portion of embodiment 2.

Fig. 7 is an enlarged photograph of a chip breaker (dimple) provided in the blade portion of embodiment 2.

Fig. 8 is an enlarged photograph of a chip breaker (groove) provided in the blade of embodiment 2.

Fig. 9 (a) is an enlarged perspective view of a chip breaker (projection) provided in the blade portion of embodiment 3. Fig. 9(b) is a sectional view taken along line b-b of fig. 9 (a).

Fig. 10 is an enlarged photograph of a chip breaker (projection) provided in the blade portion of embodiment 2.

Fig. 11 is an enlarged perspective view of a chip breaker provided in the blade (a) of test 1.

Fig. 12 is a graph showing the simulation result of test 1.

Fig. 13a is a photograph of chips generated in the cutting test (blade portion without chip breaker) of test 1.

Fig. 13b is a photograph of chips generated in the cutting test of test 1 (a blade portion having a chip breaker with an R-shaped cross section).

Fig. 13c is a photograph of chips generated in the cutting test of test 1 (a blade portion having a chip breaker with a triangular cross section).

Fig. 14a is a photograph of chips generated in the cutting test (blade without chip breaker) of test 1.

Fig. 14b is a photograph of chips generated in the cutting test of test 1 (a blade portion having a chip breaker with an R-shaped cross section).

Fig. 14c is a photograph of chips generated in the cutting test of test 1 (a blade portion having a chip breaker with a triangular cross section).

Fig. 15 is an enlarged perspective view of a chip breaker provided in the blade (a) of test 2.

Fig. 16 is a graph showing the simulation result of test 2.

Fig. 17a is an SEM photograph of the inner surface of the chip breaker after cutting in the cutting test of test 3 (condition 1).

Fig. 17b is an SEM photograph of the inner surface of the chip breaker after cutting in the cutting test of test 3 (condition 2).

Fig. 17c is an SEM photograph of the inner surface of the chip breaker after cutting in the cutting test of test 3 (condition 3).

Fig. 17d is an SEM photograph of a portion corresponding to a chip breaker after cutting in the cutting test of test 3 (condition 4).

Fig. 18 is an enlarged perspective view of a chip breaker provided in the blade (b) of test 4.

Fig. 19 is an enlarged perspective view of a chip breaker provided in the blade (c) of test 4.

Fig. 20 is a graph showing the simulation result of test 4.

Fig. 21 is a graph showing the simulation result of test 5.

Fig. 22 is an enlarged perspective view of a blade portion provided in the reamer of embodiment 4.

Fig. 23 is an enlarged perspective view of a blade portion provided in a reamer according to a modification of embodiment 4.

Fig. 24 is an enlarged perspective view of a blade portion provided in the reamer of embodiment 5.

Fig. 25 is an enlarged perspective view of a blade portion provided in a reamer according to a modification of embodiment 5.

Detailed Description

Hereinafter, a rotary tool according to the present invention will be described in detail based on embodiments. In the description of the embodiments, reference is made to the drawings as appropriate, but the form, size, relative positional relationship, and the like in the drawings can be changed without departing from the essence of the invention.

The rotary tool of the present embodiment is a tool for cutting a workpiece by contacting the workpiece as a workpiece while rotating around an axis, and is a tool for cutting a workpiece made of a metal material, particularly a nonferrous metal such as aluminum or an aluminum alloy. Such as a reamer, end mill, drill, etc. The cutting speed of the rotary tool of the present embodiment is not particularly limited. For example, the concentration of the surfactant can be 50 m/min or more, 100 m/min or more, 150 m/min or more, 600 m/min or less, 500 m/min or less, 400 m/min or less, and 300m/min or less. These upper limit value and lower limit value can be arbitrarily combined.

The rotary tool of the present embodiment includes a rotary tool body and a blade. One or more blades are disposed on the outer periphery of the rotary tool. The blade portion can be fixed by brazing, welding, or the like. Removable structures may also be employed if desired.

The blade portion has a cutting edge, and a chip breaker is provided in the vicinity of the cutting edge of the rake surface. The blade is formed of PCD or CBN. The cutting edge may be inclined with respect to the rotation axis of the rotary tool body. The rake surface is a surface against which chips cut by the cutting edge abut.

Preferably the chip breaker is formed on the rake face slightly away from the cutting edge. The chip breaker is a recess arranged on the front cutter surface. The chips contact the inner surface of the chip breaker, which functions to curl the continuously generated chips.

The chip breaker is preferably shaped such that the distance from the cutting edge is constant. That is, the width (length in the direction perpendicular to the cutting edge) of the surface (land) between the cutting edge and the chip breaker is preferably almost constant.

The appropriate value of the width of the land is preferably smaller than the single-edge feed amount of the rotary tool of the present embodiment. When a value of about 0.05mm to 0.1mm is set as the single-blade feed amount, the width of the blade edge can be exemplified by 0.01mm and 0.02mm as the lower limit value, and 0.05mm, 0.04mm and 0.03mm as the upper limit value, and these upper limit value and lower limit value can be arbitrarily combined. In particular, the width of the land is preferably set to 60% or less (particularly 50% or less) of the single-blade feed amount.

The width (length in a direction perpendicular to the cutting edge) of the chip breaker can be exemplified as 0.15mm or 0.2mm as a lower limit value, and can be exemplified as 0.5mm, 0.4mm or 0.3mm as an upper limit value, and these upper limit value and lower limit value can be arbitrarily combined.

The cross-sectional shape (direction perpendicular to the cutting edge) of the chip breaker is an R-shape in the direction of the rake face depression. The R-shape is a shape having no bending point, that is, having a smooth change in curvature. In particular, a portion of a circular arc, a portion of a hyperbola, and the like. Preferably, the inner surface of the chip breaker is formed at an angle (obtuse angle) of about 15 ° to 20 ° (165 ° to 160 °) to the land. The curvature of the R-shape may not be constant, and the curvature may be increased as the distance from the cutting edge increases.

In the case where the cutting edge of the blade portion is inclined with respect to the rotation axis of the rotary tool body, the chip breaker is preferably a depression which becomes continuously shallower as approaching the end in the outer peripheral direction and/or the axial direction of the rotary tool body at both ends in the direction parallel to the cutting edge. Hereinafter, the chip breaker refers to both ends in a direction parallel to the cutting edge without being particularly limited, and refers to a cross section in a direction perpendicular to the cutting edge without being particularly limited, in the case of being referred to as "cross-sectional shape". The "width" of the chip breaker is not particularly limited, and refers to a length in a direction perpendicular to the cutting edge.

For example, as the shape of the recess of the chip breaker, a combination shape of a central portion, which is a portion whose sectional shape is not changed, and tapers (both end portions), which are portions successively shallower toward both ends of the central portion, and which converge the sectional shape of the central portion at one point as a bottom surface, can be adopted.

The inner surface of the chip breaker preferably has a low surface roughness. For example, the value of the surface roughness Rz can be 2.0 μm or less and 1.5 μm or less. By reducing the surface roughness, the welding of the material to be cut to the surface of the blade portion (particularly, the inner surface of the chip breaker) can be suppressed. In addition, Rz in the present specification represents ten-point average roughness.

The chip breaker preferably has a texture formed by asperities on its inner surface. As the texture form, pits (concave portions) and bumps (convex portions) are exemplified, which are regularly arranged. Grooves formed by connecting a plurality of recesses may be formed, and rib-like projections formed by connecting a plurality of bumps may be formed. By providing the groove as extending in a direction parallel to the cutting edge, the effect of reducing the friction coefficient can be improved. The rib-like protrusion extends in the width direction of the chip breaker, and thus controllability of the flow of chips can be improved.

When the dimples and the protrusions are formed on the inner surface of the chip breaker, a friction reducing effect between the inner surface of the chip breaker and the chips can be expected, and the flow of the chips on the inner surface of the chip breaker can be controlled. In particular, when the friction between the chip and the chip breaker inner surface is reduced, the curling of the chip is promoted and the breaking of the chip can be promoted. Further, the oil used for cutting can be expected to be stored in the pits and the bumps. When the flow of the chips is deflected, the chips may be formed into a spiral shape and may not be always broken. Therefore, the chip breaking can be promoted by controlling the flow of the chips so that the leading end of the chips promptly contacts the workpiece, the chips themselves.

Here, the function as the dimples can be preferentially expected to be a friction reducing function, and the function as the protrusions can be preferentially expected to be a chip flow control function.

The chip breaker is formed by electric discharge machining, electron beam machining, laser machining, grinding machining, and the like. The texture provided on the inner surface of the chip breaker can be formed by electric discharge machining, electron beam machining, laser machining, polishing, or the like. The formation of the texture may be performed simultaneously with the formation of the chip breaker or may be performed independently of the formation of the chip breaker.

(embodiment mode 1)

The rotary tool according to the present embodiment will be described in detail below with reference to the drawings. As shown in fig. 1, the rotary tool 1 of the present embodiment includes a rotary tool body 10 and a blade portion 20 provided on an outer periphery of the rotary tool body 10. The rotary tool 1 is a reamer which rotates clockwise and performs cutting.

The rotary tool body 10 has a substantially cylindrical shape, and a notch 11 is formed from the axial tip to the middle. A blade portion 20 is fixed to the tip of the notch 11 by brazing. The number of the blades 20 is not particularly limited. The blade portion 20 is made of PCD, and as shown in fig. 2, a cutting edge 21 is formed, and a chip breaker 22 is formed on a rake face 21a. The chip breaker 22 is formed in the vicinity of the cutting edge 21. The width of the chip breaker 22 is set to about 0.2mm to 0.3 mm.

As shown in fig. 3, the length of the center portion 22a of the chip breaker 22 in the direction parallel to the cutting edge 21 is a size that accommodates chips generated by cutting. For example, the cutting depth (machining allowance) of the workpiece in the radial direction may be set to a value (about 0.15mm to 0.5 mm) larger than the machining allowance, in order to generate chips having a size of about the cutting depth (machining allowance). The position of the chip breaker 22 is also determined according to the position of the chips generated by cutting.

The length of the

end portions

22b and 22c of the chip breaker 22 in the direction parallel to the cutting edge 21 can be set to about 0.2mm to 0.3 mm. The shape of the chip breaker 22 on the cutting edge 21 side is parallel to the shape of the cutting edge 21, and the width x1 of the land 21a1 between them can be set to about 0.01mm to 0.05 mm.

The chip breaker 22 includes a central portion 22a having a circular arc cross section and end

portions

22b and 22c at both ends thereof. Here, the end portion 22c is an end portion in the outer circumferential direction of the rotary tool body 10. The end portion 22b is an oblique cone having an apex 22b1 and a bottom surface that is a cross section of the central portion 22a, and the end portion 22c is an oblique cone having an apex 22c1 and a bottom surface that is a cross section of the central portion 22a. Each of the

end portions

22b and 22c is a recess having a shape that becomes continuously shallower as it goes toward both ends.

As shown in fig. 4, the cross section of the center portion 22a of the chip breaker 22 is a part of a circular arc. The angle θ between the land 21a1 and the central portion 22a can be set to about 15 ° to 20 °.

(modification of embodiment 1)

As shown in fig. 5, the rotary tool 2 of the present embodiment includes a rotary tool body 30, and

blade portions

40 and 50 provided on the outer periphery of the rotary tool body 30. The rotary tool body 30 has a substantially cylindrical shape, and has a notch 31 formed in a part thereof from the front end to the rear end in the axial direction, and a notch 32 formed in a part thereof further toward the rear end. The

cutouts

31 and 32 are provided at every 90 ° in the circumferential direction of the rotary tool body 30. The outer diameter of the rotary tool body 30 is slightly larger in one of the portions where the notches 32 are formed than in the portion where the notches 31 are formed.

Two blade portions 40 are fixed by brazing at intervals of 180 ° to the tip of the portion where the notch 31 is formed, and two blade portions 50 are fixed by brazing to the tip of the portion where the notch 32 is formed at a position offset by 90 ° from the blade portion 40. The number of the

blades

40 and 50 is not particularly limited. The

blades

40 and 50 are made of PCD and have the same shape as the blade shown in fig. 2.

(embodiment mode 2)

The rotary tool of the present embodiment is the same as embodiment 1 except that the inner surface of the chip breaker is textured. Fig. 6 shows the blade 60. As in embodiment 1, the width x2 of the land 61a1 of the rake face 61a may be about 0.01mm to 0.05 mm.

In the chip breaker 62 of the blade portion 60 provided in the rotary tool of the present embodiment, a concave recess 63 is formed in the inner surface thereof. The dimples 63 are arranged in a generation direction of chips generated when a workpiece is cut by the cutting edge 61. The size of the pits 63 is not particularly limited, but may be, for example, about 0.02mm to 0.05mm in diameter and 0.01mm to 0.025mm in depth. The number of the dimples 63 is not particularly limited, and may be set to a number sufficient to completely cover the inner surface of the chip breaker 62. For example, about 4 to 6 chips can be arranged in the width direction of the central portion 62a of the chip breaker 62, and about 6 to 8 chips can be arranged in the longitudinal direction of the cutting edge 61 of the entire chip breaker 62.

Fig. 7 shows a photomicrograph of the chip breaker 62 portion of the blade 60. Fig. 8 shows a photomicrograph of the chip breaker 72 portion of the blade 70 in the case where grooves are used as the texture. The groove 73 is formed to extend in the central portion 72a in a direction parallel to the cutting edge 71, and to extend toward the vertexes 72b1 and 72c1 at both end portions 72b and 72c.

(embodiment mode 3)

The rotary tool of the present embodiment is the same as embodiment 1 except that the inner surface of the chip breaker is textured. Fig. 9 shows the blade 80. As in embodiment 1, the width x3 of the land 81a1 of the rake surface 81a may be 0.01mm to 0.05 mm.

In the chip breaker 82 of the blade portion 80 provided in the rotary tool of the present embodiment, a rib-like protrusion 83 is formed on the inner surface thereof. The protrusion 83 is provided to extend in a generation direction of chips generated when a workpiece is cut by the cutting edge 81. The width of the projection is not particularly limited, but may be wider or uniform as it approaches the central portion.

The size of the protrusion can be set to, for example, approximately 0.03mm to 0.07mm in width of the maximum portion and approximately 0.01mm to the same height as the rake surface 81a from the chip breaker bottom surface (for example, if the depth of the deepest portion of the chip breaker is 0.1mm, the upper limit of the height h of the protrusion (the height from the deepest portion of the central portion 82a to the apex of the protrusion 83) is 0.1 mm. The length of the chip breaker 82 in the width direction can be set to be approximately the same as the width of the chip breaker 22. The number of the protrusions 83 is not particularly limited, and may be set to a number sufficient to completely cover the inner surface of the chip breaker 82. For example, about 6 to 8 chips can be arranged in the width direction of the center portion 82a of the chip breaker 82. The

end portions

82b and 82c of the chip breaker 82 may be provided with the protrusions 83 or may not be provided with the protrusions 83. Fig. 10 shows a photomicrograph of the chip breaker 82 portion of the blade 80.

Examples

(test 1: study of chip breaker shape. shape of inner surface of chip breaker)

Reamer blades having three types of blade portions (a) blade portions not having a chip breaker, (b) blade portions having a chip breaker with an R-shaped cross-sectional shape (corresponding to fig. 3: the width x1 of the blade edge is 0.02mm, the width of the chip breaker is 0.3mm, and the radius of a cylinder forming an R-shaped inner surface of the chip breaker is 0.3mm), and (c) blade portions having a chip breaker with a triangular cross-sectional shape (fig. 11: the width of the blade edge 91a1 is 0.05mm, the width of the chip breaker is 0.6mm, and the angle between the inner surface of the chip breaker and the blade edge 91a1 is 15 °) were analyzed.

The cutting conditions were that the material of the cutting edge was PCD, the material to be cut was an aluminum alloy (a7075), the cutting speed was 150 m/min, the single edge feed rate was 0.1mm, and the machining allowance was 0.2 mm. The analysis result is shown in fig. 12.

As can be seen from fig. 12, the curl diameter of the chips generated by the blade portions (b) and (c) provided with the chip breaker is smaller than that of the chips generated by the blade portion (a) not provided with the chip breaker. In particular, it is found that the curl diameter of the chip generated by the cutting edge portion of (b) is smaller than that of the chip generated by the cutting edge portion of (c), and the tip of the chip rapidly contacts the surface of the workpiece. That is, it is found that the cutting edge of the cutting edge (b) is expected to break the chips more quickly because the tip of the generated chips is in contact with the surface of the workpiece more quickly than the cutting edge of the cutting edge (c).

In order to confirm the above analysis results, the cutting was actually performed under the following two conditions, and the shape of the generated chips was observed. The rotary tool has a blade diameter of 12.5mm, a total length of 100mm, a blade length of 5mm, and 2 blades.

Condition 1

An aluminum alloy (a7075) was used as a workpiece, and cutting was performed by a rotary tool having the blade portions (a) to (c) described above, with a cutting speed of 300m/min, a single-edge feed rate of 0.10mm, and a machining allowance of 0.1 mm. The results are shown in FIGS. 13a to 13 c.

The curl diameter of the chips cut by the rotary tool having the blade part of (b) is small, and spiral chips of about 8 to 10 turns are generated, and the chips are not wound around the rotary tool. On the other hand, the chips cut by the blade portion (a) having no chip breaker and the blade portion (c) having a chip breaker with a triangular cross-sectional shape generate continuous long chips and are wound around the rotary tool.

Condition 2

An aluminum alloy (ADC12) was used as a workpiece, and the workpiece was cut by a rotary tool having the blade portions (a) to (c) described above, with a cutting speed of 150 m/min, a single-edge feed rate of 0.05mm, and a machining allowance of 0.2 mm. The results are shown in fig. 14a to 14 c.

The curl diameter of the chips cut by the rotary tool having the blade portion (b) is small, and spiral chips (having a length of about 1 mm) are generated from about half to one turn, and the chips are not wound around the rotary tool.

On the other hand, the chips cut by the rotary tool having the blade portion without the chip breaker (a) can be cut in one turn, but the curl diameter of the chips is large and the chip length is as long as about 10 mm.

The chips cut by the rotary tool having the blade portion of the chip breaker (c) having a triangular cross-sectional shape have a small curl diameter, but spiral chips are generated (the chips are presumed to be deformed in the axial direction), and long chips are generated.

(test 2: study of chip breaker shape. shape of end of chip breaker)

Analysis was performed on (a) a reamer having a blade portion that is a part of a cylinder having an R-shape as the inner surface 94 of the chip breaker (fig. 15: cross-sectional R-shape, end portion is a surface perpendicular to the cutting edge 93), and (b) a reamer having a blade portion (corresponding to fig. 3) of a chip breaker having an R-shape in cross-sectional shape and an end portion that is a part of a cone. The chip breakers provided on both blades had a blade width of 0.02mm, a chip breaker width of 0.3mm, and a radius of an R-shaped cylinder forming an inner surface of the chip breaker of 0.3 mm. The cutting conditions were the same as in test 1. The analysis result is shown in fig. 16.

As is clear from fig. 16, the chips generated by the cutting edge portion in (a) are deformed leftward in the drawing (in the axial direction of the reamer), and spiral chips are generated as a whole. In the cutting edge portion of (a), it is considered that the generated chips contact the end surface 94a on the outer peripheral side of the inner surface of the chip breaker, and stress for deforming the chips toward the axial center side is applied, so that the chips are formed into a spiral shape.

In contrast, in the cutting edge portion of (b), the generated chips are considered to be able to flow from the inner surface 22a to the inner surface 22c of the chip breaker 22, and therefore, stress in the axial direction is not applied to the chips, and the chips are not formed into a spiral shape. Further, since the cutting edge of the cutting edge portion is inclined with respect to the rotation axis of the reamer, the generation speed of the chips on the outer peripheral side is high, and it is considered that the deformation of the chips toward the axial center direction by applying stress is originally a factor of the deformation of the chips toward the axial center direction.

When the chip is formed in a spiral shape, the chip is not easily broken because the tip of the chip does not contact the workpiece or the chip itself.

(test 3: influence of surface roughness of chip breaker inner surface)

The machining conditions for molding the chip breaker were changed, and the surface roughness was changed in the same chip breaker shape, and the degree of welding of the workpiece to the inner surface of the chip breaker was evaluated. The blade portion of the chipbreaker was also evaluated.

The shape of the chip breaker was the same as the chip breaker 22 of fig. 3, and the blade of test 2 (b). The width of the cutting edge was 0.02mm, the width of the chip breaker was 0.3mm, the length of the chip breaker center in the direction parallel to the cutting edge was 0.2mm, and the radius of the R-shaped cylinder forming the chip breaker inner surface was 0.3 mm. For comparison, a blade without a chip breaker was also prepared (condition 4: blade of (a) of test 1).

The surface roughness of each blade is condition 1: rz2.36 μm, condition 2: rz1.95 μm, condition 3: rz1.19 μm. The surface roughness of the portion of the blade of the chipbreaker (condition 4) corresponding to the chipbreaker was rz0.12. mu.m.

The shape of the cutter (reamer) is the same as that of the cutter (reamer) shown in figure 1, the diameter of the blade is 12.5mm, and the number of the blades is two. The test conditions were that the cutting speed was 300m/min, the single-edge feed rate was 0.1mm, and the machining allowance was 0.2mm, and 100 holes were machined in the workpiece ADC 12. SEM photographs of the inner surface of each chip breaker after the completion of the machining of 100 holes are shown in fig. 17a (condition 1), 17b (condition 2), 17c (condition 3), and 17d (condition 4).

As can be seen from the figure, clear welding of Al was observed in the rotary tool having the blade portion (Rz 2.36 μm) of condition 1, and a portion where Al was deposited thickly was confirmed (fig. 17 a). In conditions 2, 3 and 4, slight adhesion was observed (fig. 17b to 17 d).

From the results, it is understood that the welding of the work material in the chip breaker can be suppressed by setting Rz to 2.0 μm or less. As a result of the fact that welding of the material to be cut on the inner surface of the chip breaker can be suppressed, clogging of chips can be suppressed, and the effect of the chip breaker can be sufficiently exhibited as designed. As a result, the blade is less likely to be chipped. That is, by reducing the surface roughness of the chip breaker inner surface, the tool life can be extended.

(test 4: texture study)

The texture of the rake face of the blade portion is obtained by applying a texture having (a) a plane, (b) a pit: FIG. 18, (c) tank: fig. 19 illustrates the reamer having three kinds of blades. The study was carried out without a chip breaker. (b) The dimples 96 of (a) are provided at equal intervals in the direction parallel to the cutting edge 95 and in the direction parallel to the side adjacent to the cutting edge 95, and have a diameter of 0.04mm, are provided at intervals of 0.08mm in the direction parallel to the cutting edge 95, and are provided at intervals of 0.08mm in the direction parallel to the side adjacent to the cutting edge 95. (c) The grooves 98 are arranged to extend in a direction parallel to the cutting edge 97, and the width of the grooves 98 is 0.03mm and is set every 0.06 mm. The cutting conditions were the same as in test 1. The analysis result is shown in fig. 20.

As is clear from fig. 20, the curl diameter of the chips generated by the blade portions (b) and (c) is smaller than that of the chips generated by the blade portion (a), and the chips are easily broken. This is considered to be because the presence of the dimples 96 and the grooves 98 can reduce the friction between the chips and the blade.

(test 5: investigation of the texture of the inner surface of the chip breaker. Effect on protrusions)

The reamer was analyzed for (a) a blade portion of a chip breaker having an inner surface as a chip breaker and an R-shaped cross-sectional shape and a part of a cone at an end (similar to fig. 3), and (b) a blade portion having a protrusion on the inner surface of the chip breaker (corresponding to fig. 9). The chip breakers provided at the blade portions of both sides were 0.02mm in blade width, 0.3mm in width, and 0.3mm in radius of the R-shaped cylinder forming the inner surface of the chip breaker. The projections provided on the inner surface of the chip breaker at the blade portion in (b) have a width of 0.05mm and are provided at intervals of 0.07mm in a direction parallel to the cutting edge 81. The height of the projection was set to 0.01mm from the bottom surface of the chip breaker (corresponding to fig. 9 (b)).

The cutting conditions were the same as those of the chip breaker provided at the edge of the reamer used in test 1 except that the width of the center portion was larger. The analysis result is shown in fig. 21.

As can be seen from fig. 21, the chips generated by the blade portion in (a) are deformed leftward in the drawing (in the axial direction of the reamer). In contrast, in the cutting edge portion of (b), deformation toward the left side of the drawing is suppressed as compared with the chips generated by the cutting edge portion of (a). Since the cutting edge of the cutting edge portion is inclined with respect to the rotation axis of the reamer, the rate of generation of chips on the outer peripheral side is high, and stress is originally applied to the axial center side to deform the chips, thereby deforming the chips in the axial center direction of the chips. Under the conditions of this study, the length of the cutting edge in the parallel direction in the center portion was made longer than that in the other tests, and the stress applied to the chips in the axial direction was increased, whereby the chips were likely to take a spiral shape.

[ additional embodiment ]

(embodiment mode 4)

The rotary tool of the present embodiment has substantially the same configuration as the rotary tool of embodiment 1, except for the curvature of the cutting edge and the modification of the form accompanying the curvature of the cutting edge.

The cutting edge 21 of the blade portion 20 in embodiment 1 is straight and inclined with respect to the rotation axis of the rotary tool body 10. The inclined direction of the cutting edge 21 is a direction in which the diameter decreases toward the tip of the rotary tool.

In contrast, as shown in fig. 22, the cutting edge 101 of the blade portion 100 of the present embodiment, which is the same as the cutting edge 21 of embodiment 1, is tapered toward the tip of the rotary tool, but the shape of the cutting edge 101 is curved so that the taper becomes larger as it approaches the tip of the rotary tool. In other words, the cutting edge 101 has a shape that bulges in the outer diameter direction near the center in the rotational axial direction of the rotary tool.

The chip breaker 102 provided in the blade portion 100 of the present embodiment is also curved in accordance with the curvature of the cutting edge 101. The spacing of the cutting edge 101 from the cutting edge side of the chip breaker 102 is almost constant.

Here, the "width of land" in the case where the cutting edge 101 is curved as in the present embodiment means the length of the land in the direction perpendicular to the direction in which the tip of the cutting edge 101 extends, in view of the above definition (the width of the surface (land) between the cutting edge and the chip breaker (the length in the direction perpendicular to the cutting edge)). Therefore, the direction of the width of the land changes with the bending of the cutting edge 101.

The "width of the chip breaker" is also the "width of the chip breaker" along the same direction as the "width of the land". In the present embodiment, the width of the chip breaker 102 and the width of the land in the portion where the cutting edge 101 exists are set to be constant.

Here, the above-described embodiments show preferable ranges of the width of the land and the width of the chip breaker in the portion where the workpiece is cut. That is, even if the cutting edge is formed and the chip breaker is formed, the above-described preferable range and preferable mode may not be applied to a portion where the "width of land" and the "width of chip breaker" can be defined, in some cases, in a portion where the workpiece is not cut.

In the present embodiment, an appropriate range is defined for the "width of land" and the "width of chip breaker" in the portion where the workpiece is cut, but when the shape of the cutting edge 101 is determined so as to match the shape of the cut workpiece as a reason for curving the cutting edge 101, it is also assumed that the workpiece is cut across the entire area of the cutting edge 101, and in such an assumed case, it is preferable to set the "width of land" and the "width of chip breaker" in an appropriate range in the entire area of the curved cutting edge 101.

The width of the chip breaker at the center portion 102a of the chip breaker 102 corresponding to the portion where the cutting edge 101 is formed (the portion inside the straight line perpendicular to both end portions of the tip of the cutting edge 101) is constant. The inner diameter direction end 102b of the central portion 102a becomes continuously shallow toward the inner diameter direction, and the outer diameter direction end 102c of the central portion 102a becomes continuously shallow toward the outer diameter direction.

(modification of embodiment 4)

The rotary tool of the present embodiment has the same configuration as embodiment 4 except for the form of the chip breaker.

As shown in fig. 23, the rotary tool of the present embodiment constitutes a cutting edge 121. Specifically, the width of the land is constant as in embodiment 4, but the width of the chip breaker decreases in the direction toward the outer diameter. The chip breaker 122 of the present embodiment is constituted by a central portion 122a, end

portions

122b and 122c, as in embodiment 4, and the end portion 122c of these is adjacent to the cutting edge 121 and mainly functions as a chip breaker. The

end portions

122b and 122c become shallower as they go to both ends. The reason why the width of the chip breaker becomes smaller toward the outer diameter direction will be described below.

The direction in which the rotary tool of the present embodiment travels during cutting (the direction parallel to the rotary shaft of the rotary tool) is referred to as direction a. The blade 120 moves in parallel in the direction a along with the progress of cutting. The cutting allowance of the workpiece when the cutting edge 121 travels in the direction a increases as the angle between the direction a and the cutting edge of the cutting edge 121 (hereinafter, sometimes referred to as "inclination of the cutting edge") increases. In the present embodiment, since the inclination of the cutting edge 121 decreases in the radial direction, the cutting margin decreases in the radial direction.

Here, it is found from the test described later that the smaller the cutting allowance, the smaller the width of the chip breaker, and the smaller the width of the chip breaker, the higher the effect of the chip breaker tends to be.

Therefore, in order to sufficiently exhibit the effect of the chip breaker, the cutting margin corresponding to the cutting edge 121 is set to be smaller toward the outer diameter direction, and the width of the chip breaker is also set to be smaller. In other words, the inclination of the mating cutting edge becomes smaller toward the outer diameter direction, and the width of the chip breaker also becomes smaller.

(embodiment 5)

The rotary tool according to the present embodiment has substantially the same configuration as the rotary tool according to embodiment 4, except that the form of the curvature of the cutting edge is different, or the form is changed in accordance with the change of the curvature of the cutting edge.

As shown in fig. 24, the cutting edge 141 of the blade portion 140 of the present embodiment is tapered toward the tip of the rotary tool, similarly to the cutting edge 101 of embodiment 4, but the shape of the cutting edge 141 is curved such that the taper decreases as the cutting edge approaches the tip of the rotary tool. In other words, the cutting edge 141 has a shape that bulges in the inner diameter direction near the center in the rotational axial direction of the rotary tool.

The chip breaker 142 provided in the blade portion 140 of the present embodiment is also curved in accordance with the curvature of the cutting edge 141. The interval between the cutting edge 141 and the cutting edge side of the chip breaker 142 is almost constant.

The width of the chip breaker at the center portion 142a of the chip breaker 142 corresponding to the portion where the cutting edge 141 is formed (the portion inside the straight line perpendicular to both end portions of the tip of the cutting edge 141) is constant. The inner diameter direction end 142b of the central portion 142a becomes continuously shallower in the inner diameter direction, and the outer diameter direction end 142c of the central portion 142a becomes continuously shallower in the outer diameter direction.

(modification of embodiment 5)

The rotary tool of the present embodiment has the same configuration as embodiment 5 except for the form of the chip breaker.

As shown in fig. 25, the rotary tool of the present embodiment is configured to have a cutting edge 161. Specifically, the width of the land is constant as in embodiment 5, but the width of the chip breaker decreases in the radial direction. Unlike embodiment 5, the chip breaker 162 of the present embodiment is not present or small in the central portion, and is configured by

end portions

162b and 162 c. The end 162b thereof abuts the cutting edge 161. The

end portions

162b and 162c become shallower toward both ends.

When the direction a, which is the direction in which the rotary tool of the present embodiment travels during cutting, is taken as a reference, the blade portion 160 moves in parallel in the direction a along with the travel of cutting. The cutting margin of the workpiece when the cutting edge 161 travels in the direction a becomes larger as the inclination of the cutting edge 161 becomes larger.

Therefore, in order to sufficiently exhibit the effect of the chip breaker, the cutting margin corresponding to the cutting edge 161 is set to be larger toward the outer diameter direction, and the width of the chip breaker is also set to be larger. In other words, the inclination of the mating cutting edge increases in the outer diameter direction, and the width of the chip breaker also increases.

[ additional test ]

(test 6: study of the appropriate value of the width of the chip breaker)

CAE analysis was performed on a reamer having a blade portion with a chip breaker having an R-shaped cross-sectional shape (corresponding to FIG. 3: the blade width x1 is 0.02mm, the chip breaker has a width of 0.1mm to 0.6mm, and the radius of the R-shaped cylinder forming a part of the chip breaker (corresponding to the center portion 22a of the chip breaker 22 in FIG. 3) is the same as the chip breaker width). The analysis was evaluated to "good" when the chips generated by cutting contact a part of the chip breaker: excellent "or" Δ: good ", without contact, set to" x: pass-fail ". Even when the chips contacted the inner surface of the chip breaker, the value was "Δ" in the case of the tendency to clogging and "good" in the case of no tendency to clogging. Whether or not clogging tends to occur is evaluated by the length of the chip. Specifically, under the same condition except for the width of the chip breaker, the smaller the width of the chip breaker, the shorter the length of the chip, but the longer the length of the chip even if the width of the chip breaker is smaller is set to "Δ".

The cutting conditions were that the material of the cutting edge was PCD, the material to be cut was an aluminum alloy (a7075), the cutting speed was 150 m/min or 300m/min, the single edge feed rate was 0.05mm or 0.1mm, and the machining allowance was 0.1mm or 0.2 mm. The results are shown in table 1.

[ TABLE 1 ]

Watch l

As can be seen from the table, the values of the single-blade feed amount and the machining allowance greatly contribute to the determination of the appropriate value of the width of the chip breaker.

As seen from the results in table 1, (1) the width of the chip breaker can be set to 0.05mm to 0.45mm when the single-blade feed amount is set to 0.075mm or less. When the machining allowance is set to 0.15mm or less, the upper limit of the width of the chip breaker can be set to 0.55 mm.

(2) When the single-blade feed amount exceeds 0.075mm, the width of the chip breaker can be set to 0.125mm to 0.45mm (preferably 0.175mm to 0.45 mm). When the machining allowance is set to 0.15mm or less, the lower limit of the width of the chip breaker can be set to 0.005mm, and the upper limit thereof can be set to 0.55 mm.

(test 7: study of appropriate value of blade Width)

The chip breaker width and the chip breaker radius were set to 0.3mm, and the test for investigating the width of the cutting edge was performed by the same test as in test 6. The results are shown in table 2.

[ TABLE 2 ]

TABLE 2

As can be seen from the table, the values of the single-blade feed amount and the machining allowance greatly contribute to the determination of the appropriate value of the width of the land.

As seen from the results in table 2, (3) the width of the land can be set to 0.035mm or less when the single-blade feed amount is set to 0.075mm or less. When the machining allowance exceeds 0.15mm, the upper limit of the width of the land (3-1) can be set to 0.055mm at a cutting speed of 225 m/min or less, and (3-2) can be set to 0.045mm at a cutting speed of 225 m/min or more.

(4) When the single-blade feed amount exceeds 0.075mm, the width of the land can be 0.065mm or less.

It is found that the effect of the chip breaker can be sufficiently exhibited by further setting the width of the land to 60% or less of the single-blade feed amount, and therefore, it is preferable to set the width to 50% or less.

Description of reference numerals:

a rotary tool; rotating a tool body; an incision; a blade part; a blade portion; a cutting edge; a rake surface; 21a1.. margin; a chipbreaker; a central portion; an end portion; 22b1.. vertex; an end portion; 22c1.. vertex; rotating a tool body; an incision; a rake surface; an incision; a blade portion; a blade portion; a blade portion; 61.. cutting edge; a rake surface; 61a1... margin; a chipbreaker; a central portion; 63... dimples; a blade portion; 71.. cutting edge; a rake surface; a central portion; an end portion; vertex 72b1.. major; an end portion; a vertex 72c1.. major; 73.. a slot; 80.. a blade; a rake surface; 81a1... margin; 82.. a chipbreaker; a central portion; an end portion; an end portion; a protrusion; 91a1.. margin; an end face; 95.. cutting edge; 96... dimples; a cutting edge; 98.. groove

Claims

1. A rotary tool, having:

a rotary tool body; and

an edge portion having a cutting edge, the edge portion being formed of polycrystalline diamond or a sintered cubic boron nitride and being provided on the rotary tool body,

the cutting edge is inclined with respect to the rotational axis of the rotary tool body,

a chip breaker is provided on the rake face of the edge portion and in the vicinity of the cutting edge,

the chip breaker is a recess having an R-shaped cross-sectional shape in a direction perpendicular to the cutting edge, and continuously becomes shallower as it approaches end portions in the outer peripheral direction and the axial direction of the rotary tool body at both end portions in a direction parallel to the cutting edge.

2. A rotary tool, having:

a rotary tool body; and

the chip breaker is a recess having an R-shaped cross-sectional shape in a direction perpendicular to the cutting edge.

3. A rotary tool, having:

a rotary tool body; and

the chip breaker is a recess that becomes continuously shallower as it approaches an end in the outer peripheral direction and/or the axial direction of the rotary tool body at both ends in the direction parallel to the cutting edge.

4. The rotary tool according to any one of claims 1 to 3,

the width of the chip breaker in the direction perpendicular to the cutting edge is 0.15-0.5 mm.

5. The rotary tool according to any one of claims 1 to 4,

the distance between the chip breaker and the cutting edge is 0.01 mm-0.05 mm.

6. The rotary tool according to any one of claims 1 to 5,

the surface roughness Rz of the inner surface of the chip breaker is 2.0 [ mu ] m or less.

7. The rotary tool according to any one of claims 1 to 6,

the inner surface of the chip breaker has a texture formed by protrusions and recesses.

8. A cutting method for cutting an object to be cut made of a metal material,

use of a rotary tool according to any one of claims 1 to 7,

the distance between the chip breaker and the cutting edge is less than 60% of the single-edge feeding amount.