WO2020090372A1

WO2020090372A1 - Rotating tool

Info

Publication number: WO2020090372A1
Application number: PCT/JP2019/039586
Authority: WO
Inventors: 恭也山田; 南　徹; 神田　保之
Original assignee: 兼房株式会社
Priority date: 2018-10-30
Filing date: 2019-10-08
Publication date: 2020-05-07
Also published as: CN112789131A; JPWO2020090372A1

Abstract

The present invention addresses the problem of providing a rotating tool comprising a high-performance breaker. This rotating tool is provided with a rotating tool body 10 and with an edge section 20 having a cutting edge which is formed of a polycrystalline diamond (PCD) or a cubic boron nitride sintered body (CBN) and which is provided to the rotating tool body 10. The rake face of the edge section 20 is provided with a breaker located near the cutting edge. The rotating tool has a configuration (i) and/or a configuration (ii) described below: (i) a cross-section of the breaker taken in the direction perpendicular to the cutting edge has a concave shape, and (ii) the cutting edge is tilted relative to the rotation axis of the rotating tool body 10, and the breaker has a recess which continuously becomes shallower toward an end, defined with respect to the outer peripheral direction of the rotating tool body 10 and/or the axial direction, of both ends of the breaker in the direction parallel to the cutting edge.

Description

Rotary tool

The present invention relates to a rotary tool.

Some conventional rotary tools have breakers on the rake face of the blade to cut chips into shorter pieces and to reduce the curl diameter (

Patent Documents

1 and 2, etc.). Without a breaker, there are problems that the chips will be connected for a long time and entangled with the tool, hindering automatic operation, damaging the work, or biting the blade tip to chip the blade tip, so the proper action can be exerted. It is desirable to have a breaker.

JP, 2017-94467, A Japanese Patent No. 4185370

The present invention has been completed in view of the above circumstances, and it is an object to be solved to provide a rotary tool equipped with a high-performance breaker.

For the purpose of solving the above-mentioned problems, the present inventors have conducted intensive studies on the relationship between the shape of the breaker and the shape of the chips, and as a result, have completed the following invention.

A rotary tool of the present invention which solves the above-mentioned problems is a rotary tool main body and a blade portion made of polycrystalline diamond (PCD) or cubic boron nitride sintered body (CBN) and having a cutting edge provided on the rotary tool main body. And a breaker near the cutting edge on the rake face of the blade portion, and has at least one of the following configurations (i) and (ii).
(I) The breaker is a recess having an R-shaped cross section in a direction perpendicular to the cutting edge.
(Ii) The cutting edge is inclined with respect to the rotation axis of the rotary tool main body, and the breaker has an outer peripheral direction and / or an axial center of the rotary tool main body in both end portions in a direction parallel to the cutting edge. It is a dent that gradually becomes shallower toward the end of the direction.

Especially, the width of the breaker in the direction perpendicular to the cutting edge is preferably 0.15 mm to 0.5 mm.

The distance between the breaker and the cutting edge is preferably 0.01 mm to 0.05 mm.

Also, it is preferable that the breaker has a texture formed by unevenness on the surface. Further, the inner surface of the breaker preferably has a surface roughness Rz of 2.0 μm or less.

The rotary tool of the present invention having the above-mentioned configuration can cut chips generated during cutting into short pieces. As a result, it is possible to suppress the entanglement of chips with the rotary tool and the like, and to prevent the chips from scratching the surface of the work, and further, it is possible to effectively prevent chipping of the blade portion.

The curl diameter of the generated chips can be reduced by making the cross-sectional shape of the breaker (cross-section in the direction perpendicular to the cutting edge) R-shaped. In addition, both ends of the breaker (direction parallel to the cutting edge) are continuously shallower toward the outer peripheral direction and / or the axial center end of the rotary tool body, whereby the generated chips are It is possible to suppress the stress in the axial direction from being applied to the inner surface of the outer peripheral end of the breaker. When the application of stress in the axial direction to the chips is suppressed, it is possible to prevent the tips of the curled chips from being connected in a spiral shape due to the displacement in the axial direction, and it is possible to divide the generated chips into short pieces. In particular, the effect of shortening the chips can be expected more by forming the shape in which both ends of the breaker become continuously shallower toward the ends.

FIG. 3 is a perspective view showing a rotary tool (reamer) according to the first embodiment. FIG. 3 is an enlarged perspective view of a blade portion included in the reamer of the first embodiment. It is an expansion perspective view of a breaker which a blade part of Embodiment 1 has. FIG. 4 is a schematic cross-sectional view taken along the line IV-IV of FIG. 3. FIG. 6 is a perspective view showing a modification of the first embodiment. FIG. 9 is an enlarged perspective view of a breaker (dimple) included in the blade portion of the second embodiment. 7 is an enlarged photograph of a breaker (dimple) included in the blade of the second embodiment. 7 is an enlarged photograph of a breaker (groove) included in the blade of the second embodiment. FIG. 9A is an enlarged perspective view of a breaker (projection) included in the blade of the third embodiment. FIG. 9B is a sectional view taken along line bb of FIG. 9A. 9 is an enlarged photograph of a breaker (projection) included in the blade of the second embodiment. It is an expansion perspective view of the breaker which the blade part (a) of test 1 has. It is a figure which shows the simulation result of the test 1. 3 is a photograph of chips generated in a cutting test (blade portion without breaker) of Test 1. 3 is a photograph of chips produced in a cutting test of Test 1 (a blade portion having a breaker having an R-shaped cross section). 3 is a photograph of chips generated in a cutting test of Test 1 (a blade portion having a breaker with a triangular cross section). 3 is a photograph of chips generated in a cutting test (blade portion without breaker) of Test 1. 3 is a photograph of chips produced in a cutting test of Test 1 (a blade portion having a breaker having an R-shaped cross section). 3 is a photograph of chips generated in a cutting test of Test 1 (a blade portion having a breaker with a triangular cross section). It is an expansion perspective view of the breaker which the blade part (a) of the test 2 has. It is a figure which shows the simulation result of the test 2. It is a SEM photograph of the inner surface of the breaker after cutting in the cutting test (condition 1) of test 3. It is a SEM photograph of the inner surface of the breaker after cutting in the cutting test (condition 2) of test 3. It is a SEM photograph of the inner surface of the breaker after cutting in the cutting test (condition 3) of test 3. It is a SEM photograph of the part corresponding to the breaker after cutting in the cutting test (condition 4) of test 3. It is an expansion perspective view of the breaker which the blade part (b) of the test 4 has. It is an expansion perspective view of the breaker which the blade part (c) of the test 4 has. It is a figure which shows the simulation result of the test 4. It is a figure which shows the simulation result of the test 5. It is an expansion perspective view of the blade part with which the reamer of Embodiment 4 is provided. It is an expansion perspective view of a blade part with which a reamer of the modification of Embodiment 4 is provided. It is an expansion perspective view of the blade part with which the reamer of Embodiment 5 is provided. It is an expansion perspective view of a blade part with which a reamer of the modification of Embodiment 5 is provided.

The rotary tool of the present invention will be described in detail below based on the embodiments. Although the drawings are appropriately referred to in the description of the embodiments, the forms, dimensions, relative positional relationships and the like on the drawings can be changed without departing from the essence of the invention.

The rotary tool of the present embodiment is a tool that cuts a workpiece by coming into contact with a workpiece that is a workpiece while rotating the shaft, and cuts a workpiece made of a metal material, particularly a nonferrous metal such as aluminum or an aluminum alloy. It is a tool. For example, reamers, end mills, drills and the like. The cutting speed of the rotary tool of this embodiment is not particularly limited. For example, it 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, 300 m / min or less. These upper limit values and lower limit values can be arbitrarily combined.

The rotary tool of this embodiment has a rotary tool body and a blade. One to a plurality of blades are arranged on the outer circumference of the rotary tool. The blade can be fixed by brazing or welding. If necessary, a removable structure may be adopted.

The blade part has a cutting edge and a breaker near the cutting edge on the rake face. The blade portion 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 face is a face against which chips cut by the cutting edge come into contact.

The breaker is preferably formed on the rake face slightly away from the cutting edge. The breaker is a recess provided on the rake face. Chips come into contact with the inner surface of the breaker and act to curl the chips that are continuously generated.

It is preferable that the cutting edge side of the breaker be shaped so that the distance from the cutting edge is constant. That is, it is preferable that the width (the length in the direction perpendicular to the cutting edge) of the surface (land) between the cutting edge and the breaker is substantially constant.

As an appropriate value for the width of the land, it is desirable to make it smaller than the feed amount of one blade of the rotary tool of this embodiment. When a value of about 0.05 mm to 0.1 mm is set as the feed amount of one blade, the lower limit value of the land width may be 0.01 mm or 0.02 mm, and the upper limit value may be 0.05 mm or 0 mm. 0.04 mm and 0.03 mm can be exemplified, and the upper limit value and the lower limit value can be arbitrarily combined. In particular, it is preferable to set the width of the land to 60% or less (particularly 50% or less) of the feed amount per blade.

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

The cross-sectional shape of the breaker (perpendicular to the cutting edge) is an R shape that is recessed from the rake face. The R shape is a shape having no bending point, that is, a change in curvature is smooth. In particular, it is a part of an arc, a part of a hyperbola, and the like. The inner surface of the breaker and the land are preferably formed at an angle (obtuse angle) of about 15 ° to 20 ° (165 ° to 160 °). Further, the curvature of the R shape does not have to be constant, and the curvature may increase as the distance from the cutting edge increases.

When the cutting edge of the blade portion is inclined with respect to the rotation axis of the rotary tool body, the breaker is an end portion in the outer peripheral direction and / or the axial center direction of the rotary tool body among both end portions in the direction parallel to the cutting edge. It is preferable that the dents become shallower continuously as they go to. Hereinafter, with respect to the breaker, when the term “both ends” is used without particular limitation, it means both ends in the direction parallel to the cutting edge, and when the term “cross-sectional shape” is used without particular limitation, it is perpendicular to the cutting edge direction. Means a cross section in any direction. The "width" of the breaker means the length in the direction perpendicular to the cutting edge, unless otherwise specified.

For example, as the shape of the recess of the breaker, the central part where the cross-sectional shape does not change, and the conical body whose bottom surface has the cross-sectional shape of the central part as the part that becomes shallower toward both ends of the central part A combination shape with (both ends) can be adopted.

It is preferable that the inner surface of the breaker has a small surface roughness. For example, the value of the surface roughness Rz can be 2.0 μm or less or 1.5 μm or less. By reducing the surface roughness, it is possible to suppress the work material from welding to the surface of the blade portion (in particular, the inner surface of the breaker). In addition, Rz in this specification shows a ten-point average roughness.

-It is preferable that the inner surface of the breaker has a texture formed by unevenness. Examples of the texture form include regularly arranged dimples (concave portions) and dots (convex portions). A dimple may form a groove in which a plurality of dimples are connected, or a dot may form a rib-shaped projection in which a plurality of dimples are connected. By providing the groove so as to extend in the direction parallel to the cutting edge, the effect of reducing the friction coefficient can be improved. By providing the rib-shaped projection so as to extend in the width direction of the breaker, the controllability of the chip flow can be improved.

When dimples and dots are formed on the inner surface of the breaker, it can be expected that the friction reduction effect between the inner surface of the breaker and the chips and the flow of chips on the inner surface of the breaker can be controlled. In particular, when the friction between the chips and the inner surface of the breaker is reduced, the curling of the chips is promoted and the fragmentation of the chips can be promoted. In addition, the dimples and dots can be expected to have a function of storing oil used for cutting. If the chip flow is deflected, the chips may spiral and become uninterrupted. Therefore, the flow of the chips is controlled so that the tip of the chips quickly contacts the work or the chips themselves, so that the cutting of the chips can be promoted.

▽ Here, friction reduction effect can be prioritized as the effect of dimples, and chip flow control effect can be expected as the effect of dots.

Breakers are molded by electrical discharge machining, electron beam machining, laser machining, grinding, etc. The texture formed on the inner surface of the breaker can also be formed by electric discharge machining, electron beam machining, laser machining, grinding, or the like. The texture may be formed at the same time as the breaker is formed, or may be formed independently of the breaker.

(Embodiment 1)
The rotary tool of this 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 main body 10 and a blade portion 20 provided on the outer periphery of the rotary tool main body 10. The rotary tool 1 is a reamer that rotates clockwise to perform cutting.

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

Further, as shown in FIG. 3, the length of the central portion 22a of the breaker 22 in the direction parallel to the cutting edge 21 is set to a size that can accommodate the size of the chips generated by cutting. For example, since a chip having a size approximately equal to the cutting depth (working allowance) in the radial direction of the work is generated, the value can be made larger than the size of the working allowance (about 0.15 mm to 0.5 mm). .. The position of the breaker 22 is also determined according to the position of the chips generated by cutting.

The length of the

ends

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

The breaker 22 includes a central portion 22a whose cross-sectional shape is a part of an arc, and end

portions

22b and 22c at both ends thereof. Here, the end 22c is the end of the rotary tool body 10 in the outer peripheral direction. The end 22b is a pyramid having a vertex 22b1 and a bottom surface having a cross section of the central portion 22a, and the end 22c is a pyramid having a vertex 22c1 and a bottom having a cross section of the central portion 22a. Both of the

end portions

22b and 22c are recesses each having a shape that gradually becomes shallower toward both ends.

The cross section of the breaker 22 at the central portion 22a is a part of an arc, as shown in FIG. The angle θ between the land 21a1 and the central portion 22a can be about 15 ° to 20 °.

(Modification of Embodiment 1)
As shown in FIG. 5, the rotary tool 2 of the present embodiment has a rotary tool main body 30 and

blade portions

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

notches

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 at the portion where the notch 32 is formed than at the portion where the notch 31 is formed.

Two blades 40 are provided at every 180 ° at the tip of the portion where the notch 31 is formed, and a blade 50 is provided at a portion that is offset by 90 ° from the blade 40 at the tip of the portion where the notch 32 is formed. Two of them are fixed by brazing. The number of

blades

40 and 50 provided is not particularly limited. The

blade portions

40 and 50 are made of PCD and have the same shape as that shown in FIG.

(Embodiment 2)
The rotary tool of the present embodiment is the same as that of the first embodiment except that a texture is formed on the inner surface of the breaker. The blade 60 is shown in FIG. As for the land 61a1 of the rake face 61a, the width x2 can be set to about 0.01 mm to 0.05 mm as in the first embodiment.

A dimple 63 is formed on the inner surface of the breaker 62 of the blade portion 60 included in the rotary tool of this embodiment. The dimples 63 are provided so as to be aligned in the chip generation direction generated when the workpiece is cut by the cutting edge 61. The size of the dimples 63 is not particularly limited, but can be, for example, a diameter of about 0.02 mm to 0.05 mm and a depth of 0.01 mm to 0.025 mm. The number of the dimples 63 is not particularly limited, and may be set to a number that can evenly cover the inner surface of the breaker 62. For example, 4 to 6 pieces may be arranged in the width direction of the central portion 62a of the breaker 62, and about 6 to 8 pieces may be arranged in the length direction of the cutting edge 61 of the entire breaker 62.

Fig. 7 shows a micrograph of the breaker 62 of the blade 60. Further, FIG. 8 shows a micrograph of the breaker 72 portion of the blade portion 70 when the groove is used as the texture. The groove 73 is formed so as to extend in a direction parallel to the cutting edge 71 at the central portion 72a, and to extend toward the vertices 72b1 and 72c1 at both end portions 72b and 72c.

(Embodiment 3)
The rotary tool of the present embodiment is the same as that of the first embodiment except that a texture is formed on the inner surface of the breaker. The blade portion 80 is shown in FIG. The width x3 of the land 81a1 of the rake face 81a can be set to about 0.01 mm to 0.05 mm as in the first embodiment.

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

As for the size of the protrusion, for example, the maximum width is about 0.03 mm to 0.07 mm, the height from the bottom of the breaker is about 0.01 mm to the rake face 81a (for example, the depth of the deepest part of the breaker is When the height is 0.1 mm, the upper limit of the height h of the protrusion (the height from the deepest part of the central portion 82a to the apex of the protrusion 83) is set to 0.1 mm. It is about half the depth of. The length of the breaker 82 in the width direction can be made approximately the same as the width of the breaker 22. The number of the projections 83 is not particularly limited, and may be set to a number that can evenly cover the inner surface of the breaker 82. For example, about 6 to 8 pieces can be arranged in the width direction of the central portion 82a of the breaker 82. The protrusions 83 may or may not be arranged on the

ends

82b and 82c of the breaker 82. A photomicrograph of the breaker 82 portion of the blade 80 is shown in FIG.

(Test 1: Examination of breaker shape. Shape of breaker inner surface)
(A) A blade portion not having a breaker, (b) A blade portion having a breaker having an R-shaped cross section (corresponding to FIG. 3: land width x1 is 0.02 mm, breaker width is 0.3 mm, The radius of the cylinder forming the R shape of the inner surface is 0.3 mm, and (c) the blade having a breaker having a triangular sectional shape (Fig. 11: the width of the land 91a1 is 0.05 mm, the breaker width is 0.6 mm, the breaker is An analysis was performed on a reamer having three blade portions whose inner surface and the land 91a1 have an angle of 15 °.

As the cutting conditions, the material of the cutting edge was PCD, the work material was aluminum alloy (A7075), the cutting speed was 150 m / min, the feed rate per blade was 0.1 mm, and the machining allowance was 0.2 mm. The analysis result is shown in FIG.

As is clear from FIG. 12, the chips produced by the blade portions of (b) and (c) provided with the breaker are more likely to generate chips than the chips produced by the blade portion of (a) having no breaker. The curl diameter has decreased. In particular, it has been found that the chips generated by the blade part of (b) have a smaller curl diameter than the chips generated by the blade part of (c), and the tips of the chips contact the surface of the work material promptly. It was That is, in the blade part of (b), the tip of the generated chips comes into contact with the surface of the work material more quickly than in the blade part of (c), so that it can be expected that the cutting of chips will be performed more quickly. I understood.

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

・ Condition 1
Aluminum alloy (A7075) is used as the work material, the cutting speed is 300 m / min, the blade feed amount is 0.10 mm, and the machining allowance is 0.1 mm. The rotation includes the blade portions (a) to (c) described above. Cutting was performed with a tool. The results are shown in Figures 13a-13c.

Chips cut with a rotary tool equipped with the blade part of (b) have a small curl diameter, and spiral chips of about 8 to 10 turns are generated, and the chips were never wrapped around the rotary tool. On the other hand, the chips cut by the blade part (a) where the breaker does not exist and the blade part (c) having the breaker having a triangular cross-section have long continuous chips and are wound around the rotary tool.

・ Condition 2
An aluminum alloy (ADC12) was used as the work material, the cutting speed was 150 m / min, the feed amount per tooth was 0.05 mm, and the cutting allowance was 0.2 mm, and the above-mentioned blade portions (a) to (c) were provided. Cutting was performed with a rotary tool. The results are shown in Figures 14a-14c.

Chips cut with a rotary tool equipped with the blade part of (b) have a small curl diameter, and spiral chips (about 1 mm in length) of about half a turn to one turn are generated, and the chips may wind around the rotary tool. There was no.

On the other hand, chips cut with a rotary tool equipped with a blade part (a) without a breaker can be cut with one turn, but the curl diameter of the chips is large and the chip length is as long as about 10 mm. It was

The chips cut with a rotary tool equipped with a blade part (c) having a breaker with a triangular cross-section have spiral curls (the chips are deformed in the axial direction, although the curl diameter of the chips is small. It is speculated that) and long chips were generated.

(Test 2: Examination of breaker shape. Shape of breaker end)
(A) A reamer having a blade portion which is a part of a cylinder having an R shape as the inner surface 94 of the breaker (FIG. 15: R shape in cross section. The end portion is a surface perpendicular to the cutting edge 93.), and (b) has a cross sectional shape. An analysis was performed for each reamer having an R shape and a blade portion (corresponding to FIG. 3) having a breaker with a part of a conical end. The breakers provided on both blades each have a land width of 0.02 mm, a breaker width of 0.3 mm, and a radius of a cylinder forming the R shape of the inner surface of the breaker of 0.3 mm. The cutting conditions are the same as in Test 1. The analysis result is shown in FIG.

As is clear from FIG. 16, the chips generated at the blade portion of (a) are deformed to the left of the drawing (axial direction of the reamer), and spiral chips are generated as a whole. In the blade portion of (a), the generated chips come into contact with the end surface 94a on the outer peripheral side of the inner surface of the breaker, so that the stress that deforms the chips toward the shaft side is applied, and the chips have a spiral shape. Conceivable.

On the other hand, in the blade portion of (b), since the generated chips can flow from the inner surface 22a of the breaker 22 to the inner surface 22c, a stress in the axial direction is not applied to the chips, so that the chips do not spiral. it is conceivable that. Further, since the cutting edge of the blade is inclined with respect to the rotation axis of the reamer, the rate of generation of chips is higher on the outer peripheral side, and stress is originally applied so that the chips deform toward the shaft core side. Is also considered to be a cause of the deformation of the chips in the axial direction.

When the chips become spiral, the tip of the chips does not come into contact with the work material or the chips themselves, making it difficult to divide the chips.

(Test 3: Influence of surface roughness of breaker inner surface)
The processing conditions for forming the breaker were changed, the surface roughness of the breaker having the same shape was changed, and the degree of welding of the work material to the inner surface of the breaker was evaluated. The evaluation was also performed on the blade portion without a breaker.

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

The surface roughness of each blade was Condition 1: Rz 2.36 μm, Condition 2: Rz 1.95 μm, Condition 3: Rz 1.19 μm. The surface roughness of the portion corresponding to the breaker in the blade portion without breaker (Condition 4) was Rz 0.12 μm.

The shape of the blade (reamer) is the same as in Fig. 1, with a blade diameter of 12.5 mm and two blades. The test conditions were a cutting speed of 300 m / min, a single-blade feed amount of 0.1 mm, and a machining allowance of 0.2 mm, and the workpiece ADC12 was machined into 100 holes. 17A (condition 1), 17b (condition 2), 17c (condition 3), and 17d (condition 4) are SEM photographs of the inner surface of each breaker after processing 100 holes.

As is clear from the figure, a clear welding of Al was observed in the rotary tool with the blade of condition 1 (Rz 2.36 μm), and a thick deposit of Al was confirmed (Fig. 17a). Regarding Conditions 2, 3 and 4, a slight adhesion was observed (FIGS. 17b to 17d).

From these results, it was found that by setting Rz to 2.0 μm or less, welding of the work material inside the breaker can be suppressed. As a result of suppressing welding of the work material on the inner surface of the breaker, clogging of chips can be suppressed, and the effect of the breaker can be fully exerted as designed. As a result, the blade is less likely to be damaged. That is, the tool life can be extended by reducing the surface roughness of the inner surface of the breaker.

(Test 4: Examination of texture)
As the texture of the rake face of the blade portion, analysis was carried out on a reamer having three blade portions: (a) plane, (b) dimple: FIG. 18, (c) groove: FIG. I examined without a breaker. The dimples 96 in (b) 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 0.04 mm and are parallel to the cutting edge 95. It is provided every 0.08 mm in the direction and every 0.08 mm in the direction parallel to the side adjacent to the cutting edge 95. The groove 98 of (c) is extended in the direction parallel to the cutting edge 97, and the width of the groove 98 is provided every 0.03 mm and 0.06 mm. The cutting conditions are the same as in Test 1. The analysis result is shown in FIG.

As is clear from FIG. 20, the chips generated in the blade portions of (b) and (c) have a smaller curl diameter than the chips generated in the blade portion of (a), and the chips are divided. I found it easy. It is considered that this is because the presence of the dimples 96 and the grooves 98 can reduce the friction between the chips and the blade.

(Test 5: Examination of texture on inner surface of breaker. Effect of protrusion)
(A) An inner surface of the breaker has an R-shaped cross section and a breaker having a part of a conical end portion (similar to FIG. 3), (b) a blade portion having a protrusion on the inner surface of the breaker (equivalent to FIG. 9) ) Was analyzed for a reamer having two blades. The breakers provided on both blades each have a land width of 0.02 mm, a breaker width of 0.3 mm, and a radius of a cylinder forming the R shape of the inner surface of the breaker of 0.3 mm. The protrusion provided on the inner surface of the breaker of the blade portion of (b) has a width of 0.05 mm, and is provided every 0.07 mm in the direction parallel to the cutting edge 81. The height of the protrusion is 0.01 mm from the bottom surface of the breaker (corresponding to FIG. 9B).
The cutting conditions are the same except that the width of the central portion is larger than that of the breaker provided on the blade portion of the reamer used in Test 1. The analysis result is shown in FIG.

As is clear from FIG. 21, the chips generated by the blade portion in (a) are deformed to the left side of the drawing (axial direction of the reamer). On the other hand, in the blade part of (b), the deformation to the left of the drawing is suppressed more than the chips generated in the blade part of (a). Since the cutting edge of the blade is inclined with respect to the rotation axis of the reamer, the rate of chip generation on the outer peripheral side is higher, and stress is originally applied to the chip to deform it on the shaft core side. It deforms in the axial direction. Under the present study conditions, the length of the central cutting edge in the parallel direction was made longer than in other tests, so the stress applied to the chips in the axial direction was large, and the chips tended to form a spiral shape. However, even under such a condition, it is possible to effectively suppress the spiral deformation of the chips by providing the protrusions and controlling the flow of the chips.

[Additional Embodiment]
(Embodiment 4)
The rotary tool of the present embodiment has substantially the same configuration as the rotary tool of the first embodiment, except that the cutting edge is curved and the shape and the like are changed due to the bending of the cutting edge.

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

On the other hand, as shown in FIG. 22, the cutting edge 101 of the blade portion 100 of the present embodiment is reduced in diameter toward the tip of the rotary tool, as in the cutting edge 21 of the first embodiment, toward the tip of the rotary tool. However, the shape of the cutting edge 101 is curved so that the degree of diameter reduction increases toward the tip of the rotary tool. In other words, the shape of the cutting edge 101 is such that the vicinity of the center in the rotation axis direction of the rotary tool swells in the outer diameter direction.

The breaker 102 provided on the blade portion 100 of the present embodiment is also curved according to the curvature of the cutting edge 101. The distance between the cutting edge 101 and the cutting edge of the breaker 102 is substantially constant.

Here, the “land width” in the case where the cutting edge 101 is curved as in the present embodiment means the above-described definition (the width of the surface (land) between the cutting edge and the breaker (the direction perpendicular to the cutting edge). Length)), the length of the land in the direction perpendicular to the direction in which the cutting edge of the cutting edge 101 extends. Therefore, the direction in which the width of the land is measured changes as the cutting edge 101 bends.

Regarding the “breaker width”, the length in the same direction as the “land width” is the “breaker width”. In the present embodiment, the width of the breaker 102 and the width of the land in the portion where the cutting edge 101 exists are set to be constant.

Here, in the above-described embodiment, the preferable range of the width of the land and the width of the breaker in the portion where the object to be cut is cut is presented. That is, even if the cutting edge is formed and the breaker is formed, in the portion that does not cut the object to be cut, even if the "land width" or the "breaker width" can be defined, the above-mentioned preferable range or The preferred form may not apply.

In the present embodiment as well, an appropriate range is defined for the "land width" and the "breaker width" in the portion for cutting the object to be cut, but the reason why the cutting edge 101 is curved is to cut the object to be cut after cutting. In order to match the shape, when the shape of the cutting edge 101 is determined, it is also assumed that the object to be cut is cut over the entire area of the cutting edge 101. In such a case, a curved cutting edge can be cut. It is desirable to set an appropriate range of “land width” and “breaker width” in the entire area of the blade 101.

The width of the breaker is constant at the central portion 102a of the breaker 102, which corresponds to the part where the cutting edge 101 is formed (the part inside the straight line perpendicular to both ends of the cutting edge of the cutting edge 101). An inner diameter end 102b of the central portion 102a is continuously shallowed toward the inner diameter direction, and an outer diameter end 102c of the central portion 102a is continuously shallowed toward the outer diameter direction. ..

(Modification of Embodiment 4)
Except for the forms of the rotary tool and breaker of this embodiment, it has the same configuration as that of the fourth embodiment.

The rotary tool of this embodiment has a cutting edge 121 as shown in FIG. Specifically, the width of the land is constant as in the fourth embodiment, but the width of the breaker becomes smaller toward the outer diameter direction. The breaker 122 of the present embodiment is composed of a central portion 122a and end

portions

122b and 122c as in the fourth embodiment, and the end portion 122c of the breaker 122 is adjacent to the cutting edge 121 and mainly exerts the function as a breaker. .. The ends 122b and 122c become shallower toward both ends. The reason why the width of the breaker becomes smaller as it goes in the outer diameter direction is as follows.

The direction in which the rotary tool of this embodiment advances during cutting (direction parallel to the rotary axis of the rotary tool) is designated as direction A. The blade 120 moves in parallel with the direction A as the cutting progresses. When the cutting edge 121 advances in the direction A, the cutting allowance of the object to be cut becomes larger in the angle between the direction A and the cutting edge of the cutting edge 121 (hereinafter, may be referred to as “the inclination of the cutting edge”). Grows bigger and bigger. In the present embodiment, the inclination of the cutting edge 121 is smaller in the outer diameter direction, and thus the cutting allowance is smaller in the outer diameter direction.

Here, it is known from the test described below that the smaller the cutting allowance is, the smaller the width of the breaker can be made, and the smaller the width of the breaker is, the higher the effect of the breaker tends to be.

Therefore, in order to fully exert the effect of the breaker, the width of the breaker is set so as to correspond to the reduction of the cutting allowance of the cutting edge 121 toward the outer diameter direction. This can be said in other words that the width of the breaker is made smaller as the inclination of the cutting edge becomes smaller in the outer diameter direction.

(Embodiment 5)
The rotary tool of the present embodiment has substantially the same configuration as that of the rotary tool of the fourth embodiment, except that the curved shape of the cutting edge is different and the shape and the like are changed due to the change of the curved shape of the cutting edge.

As shown in FIG. 24, the cutting edge 141 of the blade portion 140 of the present embodiment has a diameter that decreases toward the tip of the rotary tool toward the tip of the rotary tool, similar to the cutting edge 101 of the fourth embodiment. The shape of the cutting edge 141 is curved so that the degree of diameter reduction becomes smaller toward the tip of the rotary tool. In other words, the shape of the cutting edge 141 is such that the vicinity of the center in the rotation axis direction of the rotary tool swells in the inner diameter direction.

The breaker 142 provided on the blade 140 of the present embodiment is also curved according to the curvature of the cutting edge 141. The distance between the cutting edge 141 and the cutting edge side of the breaker 142 is substantially constant.

The center part 142a of the breaker 142, which corresponds to the part where the cutting edge 141 is formed (the part inside the straight line perpendicular to both ends of the cutting edge of the cutting edge 141), has a constant breaker width. The inner diameter direction end portion 142b of the central portion 142a is continuously shallowed in the inner diameter direction, and the outer diameter direction end portion 142c of the central portion 142a is continuously shallowed in the outer diameter direction. ..

(Modification of Embodiment 5)
Except for the forms of the rotary tool and breaker of the present embodiment, it has the same configuration as that of the fifth embodiment.

The rotary tool of this embodiment has a cutting edge 161 as shown in FIG. Specifically, the width of the land is constant as in the fifth embodiment, but the width of the breaker becomes smaller toward the inner diameter direction. Unlike the fifth embodiment, the breaker 162 according to the present embodiment has no or a slight central portion, and includes the

end portions

162b and 162c. The end portion 162b of them is adjacent to the cutting edge 161. The ends 162b and 162c become shallower toward both ends.

Considering the direction A, which is the direction in which the rotary tool of the present embodiment advances during cutting, as a reference, the blade 160 moves in parallel with the direction A as the cutting progresses. The cutting allowance of the work piece when the cutting edge 161 advances in the direction A increases as the inclination of the cutting edge 161 increases.

Therefore, in order to fully exert the effect of the breaker, the width of the breaker is set to increase corresponding to the increase in the cutting allowance of the cutting edge 161 toward the outer diameter direction. This can be said in other words that the width of the breaker is increased as the inclination of the cutting edge increases in the outer diameter direction.

[Additional test]
(Test 6: Examination of appropriate value of breaker width)
A blade portion having a breaker with an R-shaped cross-section (corresponding to FIG. 3: land width x1 is 0.02 mm, breaker width is 0.1 mm to 0.6 mm, part of the breaker (central portion of breaker 22 in FIG. 3 CAE analysis was performed on a reamer having a radius of a cylinder forming the R shape (corresponding to 22a) is the same as the breaker width). In the analysis, when the chips generated by cutting contacted a part of the breaker, “◯: excellent” or “Δ: good”, and when not contacted, “x: acceptable to unacceptable”. Even when the chips were in contact with the inner surface of the breaker, it was evaluated as "△" when it was clogged and "○" when it was not clogged. Whether or not it was clogged was evaluated by the length of the chips. Specifically, the chip length becomes shorter as the breaker width becomes smaller under the same conditions except for the breaker width, but when the chip length becomes longer even if the breaker width becomes smaller, “△” "

As the cutting conditions, the material of the cutting edge is PCD, the work material is an aluminum alloy (A7075), the cutting speed is 150 m / min or 300 m / min, the feed rate per tooth is 0.05 mm or 0.1 mm, and the machining allowance is It was set to 0.1 mm or 0.2 mm. The results are shown in Table 1.

As is clear from the table, it was found that the single blade feed amount and the value of the machining allowance greatly contribute to the determination of the appropriate value of the breaker width.

From the results in Table 1, (1) the width of the breaker could be set to 0.05 mm to 0.45 mm when the feed rate per blade was 0.075 mm or less. When the stock removal was set to 0.15 mm or less, the upper limit of the breaker width could be set to 0.55 mm.
(2) The width of the breaker could be 0.125 mm to 0.45 mm (preferably 0.175 mm to 0.45 mm) when the single-blade feed amount was more than 0.075 mm. When the machining allowance was 0.15 mm or less, the lower limit value of the breaker width could be 0.005 mm and the upper limit value could be 0.55 mm.

(Test 7: Examination of appropriate land width)
A test for examining the land width was performed in the same test as Test 6 with the breaker width and the breaker radius set to 0.3 mm. The results are shown in Table 2.

As is clear from the table, it has been found that the value of the single-blade feed amount and the machining allowance greatly contribute to the determination of the proper value of the land width.

From the results in Table 2, (3) when the single-blade feed amount was 0.075 mm or less, the width of the land could be 0.035 mm or less. When the machining allowance exceeds 0.15 mm, the upper limit of the land width is 0.055 mm at (3-1) cutting speed of 225 m / min or less, and 0.045 mm at (3-2) cutting speed of 225 m / min or more. We were able to.
(4) When the single-blade feed amount was more than 0.075 mm, the width of the land could be 0.065 mm or less.

Further, it has been found that the width of the land is preferably 60% or less of the feed amount per blade so that the effect of the breaker can be sufficiently exerted, and more preferably 50% or less.

1 ... Rotating tool 10 ... Rotating tool main body 11 ... Notch 2 ... Blade portion 20 ... Blade portion 21 ... Cutting edge 21a ... Scooping surface 21a1 ... Land 22 ... Breaker 22a ... Central portion 22b ... End portion 22b1 ... Apex 22c ... End portion 22c1 ... Apex 30 ... Rotating tool body 31 ... Notch 31a ... Scoop face 32 ... Notch 40 ... Blade part 50 ... Blade part 60 ... Blade part 61 ... Cutting edge 61a ... Scoop face 61a1 ... Land 62 ... Breaker 62a ... Central part 63 ... Dimple 70 ... Blade portion 71 ... Cutting edge 71a ... Scooping surface 72a ... Central portion 72b ... End portion 72b1 ... Apex 72c ... End portion 72c1 ... Apex 73 ... Groove 80 ... Blade portion 81a ... Scooping surface 81a1 ... Command 82 ... breaker 82a ... middle portion 82b ... end 82c ... end 83 ... projections 91a1 ... land 94a ... end surface 95 ... cutting edge 96 ... dimples 97 ... cutting edge 98 ... groove

Claims

A rotary tool body, and a blade portion having a cutting edge made of polycrystalline diamond or cubic boron nitride sintered body and provided in the rotary tool body,
The cutting edge is inclined with respect to the rotation axis of the rotary tool body,
The rake face of the blade portion is provided with a breaker near the cutting edge,
The breaker has an R-shaped cross-sectional shape in a direction perpendicular to the cutting edge, and goes to the outer peripheral end and the axial center end of the rotary tool main body in both end portions in the parallel direction to the cutting edge. A rotating tool that is a dent that becomes shallower continuously.
A rotary tool body, and a blade portion having a cutting edge made of polycrystalline diamond or cubic boron nitride sintered body and provided in the rotary tool body,
The rake face of the blade portion is provided with a breaker near the cutting edge,
The breaker is a rotary tool that is a recess having a cross-sectional shape in an R shape in a direction perpendicular to the cutting edge.
A rotary tool body, and a blade portion having a cutting edge made of polycrystalline diamond or cubic boron nitride sintered body and provided in the rotary tool body,
The cutting edge is inclined with respect to the rotation axis of the rotary tool body,
The rake face of the blade portion is provided with a breaker near the cutting edge,
The breaker is a rotary tool that is a dent that becomes shallower continuously as it goes to an end portion in the outer peripheral direction and / or the axial center direction of the rotary tool body of both end portions in the direction parallel to the cutting edge.
The rotary tool according to any one of claims 1 to 3, wherein a width of the breaker in a direction perpendicular to the cutting edge is 0.15 mm to 0.5 mm.
The rotary tool according to any one of claims 1 to 4, wherein a distance between the breaker and the cutting edge is 0.01 mm to 0.05 mm.
The rotary tool according to any one of claims 1 to 5, wherein the inner surface of the breaker has a surface roughness Rz value of 2.0 µm or less.
The rotary tool according to any one of claims 1 to 6, wherein an inner surface of the breaker has a texture formed by unevenness.
Using the rotary tool according to any one of claims 1 to 7,
The distance between the breaker and the cutting edge is 60% or less of the feed amount of one blade,
A cutting method for cutting an object to be cut made of a metal material.