阅读说明：本技术 车削工具 (Turning tool ) 是由 植田晓彦 野原拓也 小林豊 于 2019-08-02 设计创作，主要内容包括：一种用于车削的车削工具,其具有刀杆部以及固定至刀杆部的切削刃部。切削刃部由合成单晶金刚石构成。切削刃部包括前刀面、后刀面和配置在前刀面和后刀面相交处的相交部分的切削刃,并且具有刀尖弯曲部,其曲率半径为0.1mm至1.2mm。刀尖弯曲部满足以下条件,即：将刀尖弯曲部的顶角二等分的截面和前刀面之间的交线方向相对于合成单晶金刚石的<110>方向在±10°以内的条件和/或相对于合成单晶金刚石的<100>方向在±10°以内的条件。(A turning tool for turning has a shank portion and a cutting edge portion secured to the shank portion. The cutting edge portion is composed of synthetic single crystal diamond. The cutting edge portion includes a rake face, a flank face, and a cutting edge disposed at an intersection portion where the rake face and the flank face intersect, and has a nose curved portion having a radius of curvature of 0.1mm to 1.2 mm. The nose bending portion satisfies the following conditions: the condition that the direction of the intersecting line between the cross section bisecting the apex angle of the tip curved portion and the rake face is within + -10 DEG with respect to the <110> direction of the synthetic single crystal diamond and/or within + -10 DEG with respect to the <100> direction of the synthetic single crystal diamond.)

1. A turning tool for turning, the turning tool comprising: a blade bar part; and a cutting edge portion fixed to the shank portion, wherein

The cutting edge portion is composed of synthetic single crystal diamond,

the cutting edge part includes a rake face, a flank face, and a cutting edge disposed at an intersection portion where the rake face and the flank face intersect with each other, and has a tip curved portion having a curvature radius of 0.1mm or more and 1.2mm or less, and

the nose curved portion satisfies at least one of the following conditions:

a condition that a direction of an intersection line between the rake face and a bisected section of a vertex angle of the nose curved portion is within ± 10 ° with respect to a <110> direction of the synthetic single crystal diamond, and

a condition that a direction of an intersection line between the rake face and the bisected section of the apex angle of the nose curved portion is within ± 10 ° with respect to a <100> direction of the synthetic single crystal diamond.

2. The turning tool of claim 1, wherein the intersection direction is within ± 5 ° relative to a <110> direction of the synthetic single crystal diamond.

3. The turning tool of claim 1, wherein the intersection direction is within ± 5 ° relative to a <100> direction of the synthetic single crystal diamond.

4. The turning tool according to any one of claims 1 to 3, wherein the synthetic single-crystal diamond contains nitrogen atoms in an amount of 1ppm or more and 100ppm or less.

5. The turning tool according to any one of claims 1 to 4, wherein the apex angle is 55 ° or more and 90 ° or less.

6. The turning tool according to any one of claims 1 to 5, wherein the turning is performed with a relief angle of 7 ° or more and 15 ° or less.

7. The turning tool according to any one of claims 1 to 6, wherein the turning is performed under a condition that a feed amount f is 0.01mm/rev or more and less than 0.7 mm/rev.

8. The turning tool according to any one of claims 1 to 7, wherein the synthetic single crystal diamond is a CVD single crystal diamond.

Technical Field

The present disclosure relates to a turning tool. The present application claims priority based on japanese patent application No.2018-147806, filed 8/6 in 2018, the entire contents of which are incorporated herein by reference.

Background

In general, a cutting tool (hereinafter, also referred to as a "single crystal diamond cutting tool") using a single crystal diamond at least as a cutting edge is used for machining of nonferrous metals, and mirror finishing and precision machining of plastics and the like. When single crystal diamond is used for the cutting edge of a cutting tool, as disclosed in, for example, WO 2014/003110 (patent document 1), the characteristics of the cutting tool such as wear resistance and fracture resistance are greatly different depending on what crystal plane and crystal orientation of the single crystal diamond is used for the rake face and the flank face of the cutting tool.

Therefore, the single crystal diamond cutting tool is manufactured after selecting a more suitable crystal plane and crystal orientation of the single crystal diamond according to user's needs, use conditions, and the like. For example, the single crystal diamond cutting tool of patent document 1 is manufactured to include a cutting edge having a rake face composed of a (100) face of a single crystal diamond, in which a cutting edge tip corresponds to a <100> direction.

Reference list

Patent document

Patent document 1: WO 2014/003110

Disclosure of Invention

A turning tool according to an embodiment of the present disclosure is a turning tool for turning, including: a blade bar part; and a cutting edge portion fixed to the shank portion, wherein the cutting edge portion is composed of synthetic single crystal diamond, the cutting edge portion includes a rake face, a flank face, and a cutting edge provided at an intersection portion where the rake face and the flank face intersect each other, and the cutting edge portion has a nose curved portion having a curvature radius of 0.1mm or more and 1.2mm or less, and the nose curved portion satisfies at least one of the following conditions: the condition that the direction of the intersection line between the bisector sections of the apex angles of the rake face and the nose curved portion is within + -10 DEG relative to the <110> direction of the synthetic single crystal diamond, and the condition that the direction of the intersection line between the bisector sections of the apex angles of the rake face and the nose curved portion is within + -10 DEG relative to the <100> direction of the synthetic single crystal diamond.

Drawings

Fig. 1 is an explanatory plan view showing a cutting edge portion in a turning tool according to an embodiment of the present disclosure when viewed in plan view, to explain the following terms: the "cutting edge curved portion" and the "radius of curvature", "apex angle", and "bisected cross section of apex angle" of the "cutting edge curved portion".

Fig. 2 is an enlarged plan view illustrating a cutting edge portion and a shank portion in a turning tool according to an embodiment of the present disclosure, when viewed in plan.

Fig. 3 is an enlarged perspective view illustrating a cutting edge portion of a turning tool according to one embodiment of the present disclosure.

Fig. 4 is an explanatory view showing a use state of the turning tool according to one embodiment of the present disclosure.

Detailed Description

[ problem to be solved by the present disclosure ]

In the nonferrous metal processing market, the single crystal diamond cutting tool described above is hardly used for the processing of vehicle parts. This is due to the following reasons: if such a single crystal diamond cutting tool is used for machining under the severe conditions (e.g., high speed cutting, high feed rate, and deep cutting depth) typically employed for vehicle parts, breakage often occurs and wear is liable to occur. Therefore, in order to achieve machining under severe conditions, it is necessary to impart excellent wear resistance to the single crystal diamond cutting tool. Further, there is a demand for obtaining a smooth finished surface of a processed article such as a vehicle component.

In the above practical circumstances, an object of the present disclosure is to provide a turning tool having wear resistance and giving a smooth finish to a workpiece.

[ advantageous effects of the present disclosure ]

According to the above description, it is possible to provide a turning tool having wear resistance and giving a smooth finish to a workpiece.

[ description of the embodiments ]

First, embodiments of the present disclosure are enumerated and described.

[1] A turning tool according to an embodiment of the present disclosure is a turning tool for turning, including: a blade bar part; and a cutting edge portion fixed to the shank portion, wherein the cutting edge portion is composed of synthetic single crystal diamond, the cutting edge portion includes a rake face, a flank face, and a cutting edge located at an intersection portion where the rake face and the flank face intersect each other, and the cutting edge portion has a nose curved portion having a curvature radius of 0.1mm or more and 1.2mm or less, and the nose curved portion satisfies at least one of the following conditions: the condition that the direction of the intersection line between the bisector sections of the apex angles of the rake face and the nose curved portion is within + -10 DEG relative to the <110> direction of the synthetic single crystal diamond, and the condition that the direction of the intersection line between the bisector sections of the apex angles of the rake face and the nose curved portion is within + -10 DEG relative to the <100> direction of the synthetic single crystal diamond. Turning tools with such features have wear resistance and can give the workpiece a smooth finished surface.

[2] Preferably, the direction of the intersection is within ± 5 ° with respect to the <110> direction of the synthetic single crystal diamond. Therefore, the turning tool has higher wear resistance, and can obtain a smooth finished surface of the workpiece.

[3] Preferably, the direction of the intersection is within ± 5 ° with respect to the <100> direction of the synthetic single crystal diamond. Therefore, the turning tool has higher wear resistance, and can obtain a smooth finished surface of the workpiece.

[4] Preferably, the synthetic single crystal diamond contains nitrogen atoms in an amount of 1ppm to 100 ppm. Thus, the turning tool may also have excellent fracture resistance.

[5] Preferably, the apex angle is 55 ° or more and 90 ° or less. Therefore, the turning tool is excellent in balance between cutting resistance and cutting edge strength, thereby improving wear resistance and fracture resistance.

[6] Preferably, the turning is performed under the condition that the relief angle is 7 ° or more and 15 ° or less. Thus, the turning tool may obtain a smoother finished surface of the workpiece.

[7] Preferably, the turning is performed under the condition that the feed amount f is 0.01mm/rev or more and less than 0.7 mm/rev. Thus, the turning tool may obtain a smoother finished surface of the workpiece.

[8] Preferably, the synthetic single crystal diamond is CVD single crystal diamond. Therefore, the turning tool has more sufficient wear resistance, and can obtain a smooth finished surface of the workpiece.

[ details of embodiments of the present disclosure ]

Hereinafter, an embodiment of the present disclosure (hereinafter, also referred to as "the present embodiment") is described in more detail, but the present embodiment is not limited thereto. In the following description, reference will be made to the accompanying drawings.

Here, in the present specification, the expression "a to B" represents a range from a lower limit to an upper limit (i.e., a to B). When the unit of a is not shown but only the unit of B is shown, the unit of a is the same as the unit of B. When a compound and the like are represented by chemical formulas in the present specification, and the atomic ratio is not particularly limited, it is assumed that all conventionally known atomic ratios are included. The atomic ratio is not necessarily limited to only the atomic ratio in the stoichiometric range. In the present specification, "mechanical strength" means mechanical strength including various characteristics such as wear resistance, fracture resistance, and bending strength.

In the present specification, the term "edge bent portion" refers to a region of the cutting edge portion that directly participates in cutting and comes into contact with chips of a workpiece. Specifically, the "cutting edge bent portion" refers to a part of the cutting edge portion 3 included in the imaginary semicircle (solid line) shown in fig. 1. The imaginary semicircle has, as a radius, a predetermined distance d, which is a distance extending from an intersection point o where imaginary lines (broken lines) obtained by extending the ridge lines intersect with each other, to two opposing ridge lines forming an intersection portion where the rake face and the flank face of the cutting edge portion 3 intersect with each other, respectively.

The "radius of curvature" of the nose curved portion is the inverse of the "curvature" of the curved surface of the nose curved portion. Specifically, for example, the curved surface of the nose curved portion is given by an arc included in an imaginary circle indicated by a broken line shown in fig. 1. In this case, the radius r of the imaginary circle indicated by the broken line is referred to as "curvature radius" of the cutting edge curved portion, and the reciprocal (1/r) thereof is referred to as "curvature" of the curved surface of the cutting edge curved portion. In fig. 1, the radius of curvature r of the cutting edge curved portion (the radius of an imaginary circle indicated by a broken line) is equal to the length of the distance d from the intersection o to each ridge line (d equals r).

The "vertex angle" of the nose curved portion is an angle α formed by the two imaginary lines (broken lines) in fig. 1. An imaginary cross section that bisects the angle α (i.e., the "vertex angle") is referred to as a "bisected cross section" of the vertex angle of the nose curved portion. The "clearance angle" means an angle formed between the workpiece and the flank of the cutting edge portion.

It should be noted that, when the rake face of the cutting edge portion 3 has a curved surface, the surface on the base material side of the cutting edge portion 3 or the upper surface of the base material is assumed to be the rake face, and the "intersecting line direction" between the rake face and the bisected section of the vertex angle of the tip curved portion means the intersecting line direction between the assumed rake face and the bisected section of the vertex angle of the tip curved portion.

In the present specification, "synthetic single crystal diamond" is different from natural diamond, and means artificially manufactured diamond, for example, single crystal diamond manufactured by a High Pressure High Temperature (HPHT) method, or single crystal diamond manufactured by a Chemical Vapor Deposition (CVD) method. In particular, "CVD single crystal diamond" refers to a single crystal diamond produced by epitaxially growing a diamond single crystal on a diamond single crystal substrate using a CVD method. The <110> direction of the CVD single crystal diamond refers to four equivalent crystal orientations including [01-1] of the CVD single crystal diamond. Specifically, the <110> direction of the CVD single crystal diamond means a crystal orientation composed of [01-1], [0-1-1], [0-11] and [011] of the CVD single crystal diamond. The <100> directions of CVD single crystal diamond refer to four equivalent crystal orientations including [010] of CVD single crystal diamond. Specifically, the <100> direction of the CVD single crystal diamond means a crystal orientation composed of [010], [00-1], [0-10] and [001] of the CVD single crystal diamond. Here, the symbol "-" for indicating the crystal orientation is initially located above the number, and is read as "bar (バー)". For example, [01-1] reads as "zero, one, bar".

< turning tool >)

The turning tool according to the present embodiment is a turning tool for turning. The turning tool includes: a blade bar part; and a cutting edge portion fixed to the shank portion. The cutting edge portion is composed of synthetic single crystal diamond. The cutting edge portion includes a rake face, a flank face, and a cutting edge located at an intersection portion where the rake face and the flank face intersect with each other, and has a nose curved portion having a curvature radius of 0.1mm to 1.2 mm. The nose bend portion satisfies at least one of the following conditions: a condition that the direction of the intersection line between the rake face and the bisected section of the apex angle of the nose curved portion is within ± 10 ° with respect to the <110> direction of the synthetic single crystal diamond; and the condition that the direction of the intersection line between the rake face and the bisected section of the apex angle of the nose curved portion is within + -10 DEG relative to the <100> direction of the synthetic single crystal diamond. Turning tools with such features have wear resistance and can give the workpiece a smooth finished surface.

Preferably, the turning is performed under the condition that the feed amount f is 0.01mm/rev or more and less than 0.7 mm/rev. Further, the synthetic single crystal diamond is preferably CVD single crystal diamond. Therefore, the turning tool has more sufficient wear resistance, and can obtain a smooth finished surface of the workpiece.

With regard to the turning tool according to the present embodiment, for convenience of description, the turning tool according to the first embodiment is first described below in which the direction of the intersection line between the rake face and the bisected section of the apex angle of the nose curved portion is within ± 10 ° with respect to the <110> direction of the synthetic single crystal diamond. Hereinafter, a turning tool according to a second embodiment will be described, in which the direction of the intersection line between the rake face and the bisected section of the apex angle of the nose curved portion is within ± 10 ° with respect to the <100> direction of the synthetic single crystal diamond.

Further, the following description exemplarily illustrates an embodiment in which turning is performed by the above-described turning tool under a condition that the feed amount f is 0.01mm/rev or more and less than 0.7mm/rev, and the synthetic single crystal diamond is a CVD single crystal diamond.

< first embodiment >

The turning tool according to the first embodiment is a turning tool for turning. It is preferable to perform turning under the condition that the feed amount f is 0.01mm/rev or more and less than 0.7 mm/rev. The feed amount f is determined by a relationship with a radius of curvature of a cutting edge portion (nose curved portion) of a turning tool for turning. Therefore, when the turning tool according to the first embodiment is used for turning under the condition that the feed amount f falls within the above range, the turning tool has particularly excellent wear resistance, and can obtain a smooth finished surface of the workpiece. In the present embodiment, when the turning tool is used for turning under the condition that the feed amount f is less than 0.01mm/rev, the machining time becomes significantly long. Thus, this tends to be impractical. In the present embodiment, when the turning tool is used for turning under the condition that the feed amount f is 0.7mm/rev or more, the cutting edge is easily broken and it tends to be difficult to obtain a smooth finished surface of the workpiece.

As shown in fig. 2, the turning tool 1 includes a shank portion 10 and a cutting edge portion 3 fixed to the shank portion 10. The material of the blade shaft portion 10 should not be particularly limited; however, the shank portion 10 is preferably made of, for example, steel, cemented carbide, or the like. The shape of the shank portion 10 should not be particularly limited as long as it can be used for turning. For example, the shape of the shank portion 10 may include a corner portion as shown in fig. 3 for receiving the substrate 2. The corner of the shank portion 10 is formed by partially recessing a portion of the upper surface of the shank portion 10. The cutting edge portion 3 is fixed to a corner of the shank portion 10 with the base material 2 interposed between the cutting edge portion 3 and the shank portion 10. Specifically, when the base material 2 has a hole, the cutting edge portion 3 is fixed to the shank portion 10 by using a method of being pressed in the hole (lever locking method) or a method of being screwed in the hole (screw connection method), with the base material 2 interposed between the cutting edge portion 3 and the shank portion 10. When the base material 2 has no hole, the cutting edge portion 3 is fixed to the shank portion 10 by using a pressing means such as a method of pressing and holding the upper surface of the base material 2 (pressing method), with the base material 2 interposed between the cutting edge portion 3 and the shank portion 10. The material of the base material 2 should not be particularly limited; however, the substrate 2 is preferably made of, for example, cemented carbide or the like.

(cutting edge part)

The cutting edge portion 3 is made of synthetic single crystal diamond. Specifically, in the first embodiment, the cutting edge portion 3 is composed of CVD single crystal diamond. The CVD single crystal diamond will be described below. As shown in fig. 3, the cutting edge portion 3 includes a rake face 4, a flank face 5, and a cutting edge 6 located at an intersection where the rake face 4 and the flank face 5 intersect with each other, and the cutting edge portion 3 has a tip curved portion having a curvature radius of 0.1mm or more and 1.2mm or less. Each of the rake face 4 and the flank face 5 is formed by grinding or polishing CVD single crystal diamond. The cutting edge 6 corresponds to a ridge line as an intersection portion where the rake face 4 and the flank face 5 intersect with each other. Chamfers 8 of unequal width may be provided at intersections where the rake face 4 and the flank face 5 intersect each other. In this case, the cutting edge 6 is formed on an edge line at a position where the flank face 5 and the chamfer 8 intersect each other. The chamfer 8 may also be formed by grinding or polishing CVD single crystal diamond. The rake face 4 of the cutting edge portion 3 preferably corresponds to the (100) face of the CVD single crystal diamond.

(CVD single crystal diamond)

As described above, in the first embodiment, the cutting edge portion 3 is composed of CVD single crystal diamond. CVD single crystal diamond can be produced by epitaxially growing a diamond single crystal on a diamond single crystal substrate by using a CVD method as described below. The synthetic single crystal diamond preferably contains nitrogen atoms in an amount of 1ppm to 100 ppm. Specifically, in the first embodiment, the CVD single-crystal diamond preferably contains nitrogen atoms in an amount of 1ppm or more and 100ppm or less. When the CVD single crystal diamond contains nitrogen atoms within the above range, an effect of suppressing the development of defects can be obtained even if a strong stress is applied to a specific region of the cutting edge 6. Thus, mechanical strength, such as toughness and hardness, can be improved. Thus, the turning tool may also have excellent fracture resistance. Nitrogen atoms are present as impurity elements in CVD single-crystal diamond. Here, the impurity element means an element (foreign element) other than carbon, which is a main constituent element of the single crystal diamond.

When the content of nitrogen atoms in the CVD single crystal diamond is less than 1ppm, the effect of suppressing the development of defects cannot be sufficiently obtained, with the result that the fracture resistance tends not to be improved. When the nitrogen atom content in the CVD single crystal diamond is more than 100ppm, crystal defects increase, with the result that large fractures are liable to occur in the cutting edge 6 when strong stress is applied to a specific region of the cutting edge 6. The nitrogen atom content in the CVD single-crystal diamond is preferably 20ppm to 80 ppm.

The CVD single crystal diamond may contain an impurity element other than nitrogen atoms. For example, as an impurity element other than nitrogen atoms, CVD single crystal diamond may contain silicon, boron, hydrogen, or the like. As for the impurity elements other than nitrogen atoms in the CVD single crystal diamond, only silicon and boron may be contained each in a range of 0.01ppm to 3ppm, only hydrogen may be contained in a range of 1ppm to 100ppm, and these elements may be contained in a total range of 1ppm to 100 ppm.

The content of nitrogen atoms and other impurity elements in the CVD single-crystal diamond can be measured by a Secondary Ion Mass Spectrometry (SIMS) method.

(nose bend)

As described above, the cutting edge portion has the cutting edge curved portion having a curvature radius of 0.1mm to 1.2 mm. Since the curvature radius of the curved portion of the cutting edge is 0.1mm to 1.2mm, the balance between the cutting resistance and the strength of the cutting edge becomes excellent, and the workpiece obtains a smooth finished surface. When the radius of curvature of the nose curved portion is less than 0.1mm, the cutting edge 6 becomes too sharp, with the result that it tends to be difficult to obtain a smooth finished surface. When the radius of curvature of the nose curved portion is larger than 1.2mm, the cutting resistance becomes large, with the result that the cutting edge 6 tends to be easily broken. The curvature radius of the blade edge curved portion is preferably 0.2mm to 0.8 mm. The radius of curvature of the blade edge curved portion can be measured by using a projector used for tool inspection or the like and projecting the projection on a screen in an enlarged manner.

The direction of the intersection line between the rake face 4 and the bisected section of the apex angle of the nose curved portion is within + -10 DEG relative to the <110> direction of the synthetic single crystal diamond. In particular, the direction of the intersection line between the rake face 4 and the bisected section of the apex angle of the nose curved portion is preferably within ± 5 ° with respect to the <110> direction of the synthetic single crystal diamond. That is, in the first embodiment, the direction of the intersection line between the rake face 4 and the bisected section of the apex angle of the tip curved portion may be within ± 10 ° with respect to the <110> direction of the CVD single crystal diamond, and particularly, the direction of the intersection line between the rake face 4 and the bisected section of the apex angle of the tip curved portion is preferably within ± 5 ° with respect to the <110> direction of the CVD single crystal diamond. The apex angle of the blade edge curved portion is preferably 55 ° to 90 °. The apex angle of the nose curved portion may be 35 ° to 90 °.

Here, when a turning tool using CVD single crystal diamond according to the present disclosure has a surface corresponding to a (110) plane perpendicular to a <110> direction and coming into contact with the cutting tool (i.e., being worn away when cutting), a <100> direction corresponding to a wear direction in the (110) plane is referred to as an easy-to-wear direction. Therefore, when the direction of the intersection line between the rake face 4 and the bisected section of the apex angle of the nose curved portion is within ± 10 °, preferably within ± 5 ° with respect to the <110> direction of the CVD single crystal diamond, by cutting under severe conditions in which the cutting amount (ap) of the workpiece is large, the region of the cutting edge 6 corresponding to the position where the cutting depth of the workpiece is the largest tends to be severely worn.

On the other hand, in this case, by positioning the <100> direction of the CVD single crystal diamond at the tip cutting edge boundary portion of the cutting edge 6 which is the boundary with the workpiece, the <100> direction which is a direction having wear resistance relative to the above-mentioned easy-to-wear direction (hereinafter, also referred to as "wear-resistant direction") can be positioned in the (100) plane perpendicular to the <100> direction. In particular, in the above case, the skew angle does not become large. The skew angle refers to an angle at which the <100> direction of the CVD single crystal diamond of the cutting edge 6 and the orientation of the CVD single crystal diamond at the front cutting edge boundary portion of the cutting edge 6 intersect with each other. Further, when the apex angle of the tip curved portion is 55 ° or more and 90 ° or less, in the case where the above-described deflection angle becomes small, the <100> direction in the (100) plane of the CVD single crystal diamond can be positioned at the front cutting edge boundary portion of the cutting edge 6. Advantageously, therefore, the front cutting edge boundary portion of the cutting edge 6 is relatively less prone to wear with respect to the above-mentioned direction of easy wear.

By positioning the <100> direction (wear-prone direction) in the (110) face of the CVD single crystal diamond at the region of the cutting edge 6 corresponding to the position where the cutting depth of the workpiece is the largest, and positioning the <100> direction (wear-resistant direction) in the (100) face of the single crystal diamond at the front cutting edge boundary portion, the following effects can be obtained. That is, as turning progresses, wear progresses in the region of the cutting edge 6 corresponding to the position where the cutting depth of the workpiece is the largest, but wear hardly progresses at the front cutting edge boundary portion. That is, as the turning proceeds, the amount of chips decreases in the region of the cutting edge 6 corresponding to the position where the cutting depth of the workpiece is the largest, but the amount of chips at the front cutting edge boundary portion is substantially constant.

From the viewpoint of the machined surface of the workpiece, it is considered that: as the turning proceeds, the difference in the amount of chips generated by the cutting becomes smaller between the position where the cutting depth of the workpiece is the largest and the position of the workpiece corresponding to the front cutting edge boundary portion of the cutting edge 6. Therefore, the surface roughness (Ra) of the machined surface of the workpiece becomes small. Thus, the turning tool of the present embodiment can obtain a smooth finished surface of the workpiece.

Further, since the <100> direction in the (100) plane of the CVD single crystal diamond is positioned at the tip cutting edge boundary portion of the cutting edge 6, the flank wear width is not easily widened. Therefore, the wear resistance evaluated according to the size of the flank wear width at the front cutting edge boundary portion becomes excellent. Therefore, the turning tool of the present embodiment can have excellent wear resistance.

Here, turning is preferably performed under the condition that the relief angle is 7 ° to 15 °. By turning under the condition that the relief angle falls within the above range, even when the wear of the cutting edge 6 continues, the contact between the workpiece and the flank face can be reduced as much as possible, and the cutting edge strength can be ensured. Therefore, the turning tool of the present embodiment sufficiently exhibits wear resistance and fracture resistance. It should be noted that the above turning may be performed under the condition that the relief angle is 7 ° or more and 20 ° or less. For reference, fig. 4 shows the use of the turning tool 1 during turning of a workpiece Z.

The crystal orientation of the CVD single crystal diamond in the direction of the intersection between the rake face 4 and the bisected section of the apex angle of the nose bend can be determined, for example, by laue photography using X-ray diffraction.

(action)

As described above, the turning tool according to the first embodiment has wear resistance, and can obtain a smooth finished surface of a workpiece. In particular, the turning tool according to the first embodiment is suitable for cutting under severe conditions where the cut amount (ap) is large.

< second embodiment >

The following describes a turning tool according to a second embodiment. In the following description, differences from the turning tool according to the first embodiment will be mainly described, and the same description will not be repeated.

In the turning tool according to the second embodiment, the direction of the intersection line between the rake face 4 and the bisected section of the apex angle of the nose curved portion is within ± 10 ° with respect to the <100> direction of the synthetic single crystal diamond. In particular, the direction of the intersection line between the rake face 4 and the bisected section of the apex angle of the nose curved portion is preferably within ± 5 ° with respect to the <100> direction of the synthetic single crystal diamond. That is, in the second embodiment, the direction of the intersection line between the rake face 4 and the bisected section of the tip angle of the tip bend portion may be within ± 10 ° with respect to the <100> direction of the CVD single crystal diamond, and particularly, the direction of the intersection line between the rake face 4 and the bisected section of the tip angle of the tip bend portion is preferably within ± 5 ° with respect to the <100> direction of the CVD single crystal diamond. The apex angle of the nose curvature is preferably 55 ° or more and 90 ° or less, as in the turning tool according to the first embodiment. As in the first embodiment, it is also preferable to perform turning using the turning tool according to the second embodiment under the condition that the relief angle is 7 ° or more and 15 ° or less. Further, in the second embodiment, the apex angle of the nose curved portion may be 35 ° or more and 90 ° or less, and turning may be performed under the condition that the relief angle is 7 ° or more and 20 ° or less.

The <100> direction of the CVD single crystal diamond is the wear direction described above. That is, it is known that when the surface of the (100) plane corresponding to the <100> direction perpendicular to the CVD single crystal diamond is the surface which comes into contact with the workpiece (the surface which is worn during cutting), then the <100> direction in the (100) plane is taken as the wear-resistant direction. Therefore, when the direction of the intersection line between the rake face 4 and the bisected section of the apex angle of the nose curved portion is within ± 10 °, preferably within ± 5 °, with respect to the <100> direction of the CVD single crystal diamond, wear of the region of the cutting edge 6 corresponding to the position where the cutting depth of the workpiece is the maximum is less likely to progress.

In this case, when the cutting amount (ap) in cutting is small, the orientation of the <100> direction (wear direction) close to the CVD single crystal diamond can also be positioned at the front cutting edge boundary portion as a boundary with which contact with the workpiece occurs. Therefore, the turning tool of the present embodiment may have wear resistance. Further, when the cut amount (ap) during cutting is small, the surface roughness (Ra) of the machined surface of the workpiece can be made small. Therefore, the turning tool of the present embodiment can obtain a smoother finished surface of the workpiece.

(action)

As described above, the turning tool according to the second embodiment has wear resistance, and can obtain a smooth finished surface of the workpiece. In particular, the turning tool according to the second embodiment is suitable for cutting with a small cutting amount (ap).

< method for producing turning tool (cutting edge part) >

The turning tool according to the present embodiment can be manufactured by appropriately using a conventionally known method. Therefore, the method of manufacturing the above turning tool should not be particularly limited. However, for example, it is preferable to use the following method to manufacture the cutting edge portion composed of CVD single crystal diamond in the above turning tool.

That is, an exemplary method of manufacturing the cutting edge portion is as follows: a method of making a cutting edge portion, the method comprising: a first step of preparing a single crystal substrate made of diamond; a second step of forming a conductive layer on a surface of the single crystal substrate by implanting ions into the single crystal substrate; a third step of epitaxially growing a growth layer made of diamond on the conductive layer; a fourth step of separating the single crystal substrate from the growth layer; and a fifth step of obtaining a cutting edge portion composed of CVD single crystal diamond by grinding or polishing the separated growth layer.

(first step)

First, in a first step, a single crystal substrate composed of diamond is prepared. As the single crystal substrate composed of diamond, a conventionally known single crystal substrate can be used. For example, the above-mentioned single crystal substrate can be prepared by using a single crystal substrate (type: Ib) which has a flat plate shape and is composed of diamond produced by a high-pressure high-temperature method.

The single crystal substrate is a flat plate having: a surface consisting of a (100) face of a single crystal diamond; and a side face perpendicular to the surface and composed of a (001) face and a (011) face. For a single crystal substrate, the variation in thickness of the flat plate is preferably 10% or less. The surface roughness (Ra) of the surface of the single crystal substrate is preferably 30nm or less. The shape of the surface (upper surface) of the single crystal substrate may be a quadrangular shape such as a square or a rectangle, or a polygonal shape other than a quadrangular shape such as a hexagon or an octagon.

Further, it is preferable that the surface of the single crystal substrate is etched. For example, by using oxygen (O)₂) Gas and carbon tetrafluoride (CF)₄) Reactive Ion Etching (RIE) of gas etches the surface of the single crystal substrate. The etching method should not be limited to RIE, and may be, for example, sputtering by a gas mainly composed of argon (Ar) gas.

(second step)

In the second step, a conductive layer is formed on the surface of the single crystal substrate by implanting ions into the single crystal substrate. Specifically, carbon (C) ions are implanted into the above-described etched surface of the single crystal substrate. Therefore, a conductive layer can be formed in a region including the surface of the single crystal substrate. The implanted ions should not be limited to carbon ions and may be nitrogen ions, silicon ions, phosphorus ions, or sulfur ions.

(third step)

In a third step, a growth layer composed of diamond is epitaxially grown on the conductive layer. Specifically, the single crystal substrate on which the above-described conductive layer is formed is placed in a CVD furnace having a film formed by introducing hydrogen (H)₂) Gas, methane (CH)₄) Gas and nitrogen (N)₂) Gas atmosphere, and performing microwave plasma CVD in a CVD furnace. Therefore, the single crystal diamond is epitaxially grown on the single crystal substrate with the conductive layer interposed therebetween, and a growth layer made of diamond can be formed on the conductive layer. The method of forming the growth layer should not be limited to the microwave plasma CVD method, and for example, a hot-filament CVD method, a DC plasma method, or the like may be used. By adjusting nitrogen (N) in the atmosphere of the CVD furnace₂) The amount of gas can determine the content of nitrogen atoms in the CVD single crystal diamond.

Further, for the atmosphere inside the CVD furnace, other gas including hydrocarbon such as ethane gas may be used instead of methane gas. The surface of the single crystal substrate for forming the growth layer preferably corresponds to the (100) plane, and more preferably corresponds to a plane having an off-angle of 0.5 ° or more and 0.7 ° or less with respect to the (100) plane.

(fourth step)

In the fourth step, the growth layer is separated from the single crystal substrate. Specifically, the single crystal substrate and the growth layer can be separated from each other by electrochemically etching the conductive layer in the single crystal substrate. Thus, CVD single crystal diamond (growth layer) can be obtained. The method of separating the growth layer should not be limited to the above-described electrochemical etching, and cutting may be performed using a laser, for example.

(fifth step)

In the fifth step, a cutting edge portion composed of CVD single crystal diamond is obtained by grinding or polishing the separated growth layer. Specifically, by subjecting the CVD single crystal diamond (growth layer) described above to conventionally known grinding or polishing, a cutting edge portion can be obtained which includes: a rake face; a flank face; and a cutting edge disposed at an intersection portion where the rake face and the flank face intersect each other. In this case, the cutting edge portion is ground or polished so as to have a corner curved portion having a radius of curvature of 0.1mm to 1.2 mm. Further, the formed tip bent portion satisfies at least one of the following conditions: a condition that the direction of the intersection line between the rake face and the bisected cross section of the apex angle of the nose curved portion is within ± 10 ° with respect to the <110> direction of the CVD single crystal diamond; and the direction of the intersection line between the rake face and the bisected section of the apex angle of the nose curved portion is within + -10 DEG relative to the <100> direction of the CVD single crystal diamond.

In this way, the cutting edge portion composed of CVD single crystal diamond in the present embodiment can be manufactured. For example, the turning tool according to the present embodiment can be manufactured by fixing the cutting edge portion to the corner portion of the shank portion using a known pressing means with the base material interposed between the cutting edge portion and the shank portion.

(pay)

The above description includes embodiments described further below.

(pay 1)

A turning tool for turning with a feed amount f of 0.01mm/rev or more and less than 0.7mm/rev, the turning tool comprising: a blade bar part; and a cutting edge part fixed on the shank part, wherein

The cutting edge portion is composed of CVD single crystal diamond,

the cutting edge part comprises a rake face, a flank face and a cutting edge arranged at an intersection part where the rake face and the flank face intersect with each other, and has a nose curved part having a curvature radius of 0.1mm to 1.2mm, and

the direction of the intersection line between the rake face and the bisected section of the apex angle of the nose curved portion is within + -10 DEG with respect to the <110> direction of the CVD single crystal diamond, or within + -10 DEG with respect to the <100> direction of the CVD single crystal diamond.

(pay 2)

The turning tool according to note 1, wherein the direction of the intersecting line is within ± 5 ° with respect to the <110> direction of the CVD single crystal diamond.

(pay 3)

The turning tool according to note 1, wherein the direction of the intersecting line is within ± 5 ° with respect to the <100> direction of the CVD single crystal diamond.

(pay 4)

The turning tool according to any of note 1 to note 3, wherein the CVD single crystal diamond contains nitrogen atoms in an amount of 1ppm or more and 100ppm or less.

(pay 5)

The turning tool according to any one of note 1 to note 4, wherein the vertex angle is 55 ° or more and 90 ° or less.

(pay 6)

The turning tool according to any one of note 1 to note 5, wherein the turning is performed under a condition that a relief angle is 7 ° or more and 15 ° or less.

Examples

Although the present disclosure will be described in more detail below with reference to examples, the present disclosure is not limited thereto.

< example 1>

< production of cutting edge part comprising CVD Single Crystal Diamond >

By using the above method for producing a cutting edge portion, a cutting edge portion composed of CVD single crystal diamond was produced. In example 1, for the cutting test described below, a total of 26 cutting edge portions of samples 1-1 to 1-21 and samples 1-a to 1-E shown in table 1 were made.

First, 26 single crystal substrates each having a thickness of 0.7mm and a distance (width) between side surfaces thereof of 5mm were prepared. With respect to the surfaces of these single crystal substrates, regions with a depth of 0.3 μm were etched from the surfaces, respectively, by RIE (first step).

Next, the energy of 3MeV and 3.0X 10 are added¹⁶/cm²The carbon ions are implanted at a dose of (a) to form a conductive layer on the surface of the single crystal substrate (a second step). Further, a microwave plasma CVD method was performed to epitaxially grow a growth layer composed of diamond having a thickness of 0.7mm on the conductive layer of the single crystal substrate (third step). In this case, as the atmosphere in the CVD furnace, hydrogen gas, methane gas, and nitrogen gas were used. The concentration of methane gas relative to hydrogen gas was 10 vol%, and the concentration of nitrogen gas relative to methane gas was 1 vol%. Further, the pressure in the CVD furnace was set to 10kPa, and the substrate temperature was set to 900 ℃.

Next, the growth layer (CVD single crystal diamond) is separated from the single crystal substrate by electrochemically etching the conductive layer in the single crystal substrate (fourth step). The content of nitrogen atoms in the above-described grown layer (CVD single crystal diamond) was 50ppm as measured by SIMS. Further, the above laue photo method was used to determine the crystal plane and crystal direction of the growth layer (CVD single crystal diamond).

Finally, by appropriately grinding and polishing the growth layer (CVD single crystal diamond), a cutting edge portion is obtained which includes: a rake face; a flank face; and a cutting edge disposed at an intersection portion where the rake face and the flank face intersect each other (fifth step). In grinding and polishing, the radius of curvature of the nose curved portion of each cutting edge portion of samples 1-1 to 1-21 and samples 1-a to 1-E is shown in table 1. Further, the angle at the intersection between the direction of the intersection line between the rake face and the bisected section of the apex angle of the nose bent portion and the <110> direction of the CVD single crystal diamond at the cutting edge portion described above is shown as "deflection angle" in table 1.

That is, the column of "deflection angle" in table 1 shows the angle at which the direction of the intersection line between the rake face and the bisected section of the apex angle of the nose curved portion and the <110> direction of the CVD single crystal diamond intersect with each other. In table 1, the unit of "radius of curvature" of the blade edge curved portion is mm. The apex angle of the point bent portion of each cutting edge portion of samples 1-1 to 1-21 and samples 1-a to 1-E was 60 °.

< production of turning tool >

The cutting edge portion is fixed to the shank portion (material: cemented carbide) with the base material interposed therebetween using a threaded connection method. In this manner, turning tools for samples 1-1 to 1-21 and samples 1-A to 1-E were produced, respectively. The turning tools of samples 1-1 to 1-21 correspond to examples of the present disclosure, and the turning tools of samples 1-a to 1-E correspond to comparative examples.

< cutting test >

The following cutting tests were carried out by using each of the turning tools of samples 1-1 to 1-21 and samples 1-a to 1-E. Specifically, the turning tool is attached to the turntable of the NC lathe. On the other hand, a cylindrical workpiece was fixed to a chuck of an NC lathe, and turning was performed under the following cutting conditions. In this turning, the clearance angle is set to 7 °.

(cutting conditions)

Workpiece: aluminium alloy ADC12 (four discontinuous grooves)

Cutting speed (Vc): 200 m/min

Cut amount (ap): 0.3mm

Feed amount (f): varying from 0.005mm/rev to 0.7mm/rev (see table 1).

Material of cutting oil: 2 mass% of a water-soluble emulsion.

< evaluation >

(surface roughness (Ra))

For each of the turning tools of samples 1-1 to 1-21 and samples 1-a to 1-E, the surface roughness (Ra) of the workpiece at each point in time at which the cutting distance reached 1km, 30km, and 60km by performing the above turning was measured. The surface roughness (Ra) was determined according to JIS B0601: 2001 using a surface roughness measuring apparatus. The results are shown in Table 1 under the heading "surface roughness [ Ra ]". The symbol "-" in the column of "surface roughness Ra" means that there is no numerical value because cutting cannot be completed due to breakage of the cutting edge. It will be appreciated that the smaller the values indicated in the column "surface roughness Ra", the smoother the finished surface obtained by the corresponding test piece.

(flank wear width of cutting edge in region corresponding to position of maximum cutting depth of workpiece)

For each of the turning tools of samples 1-1 to 1-21 and samples 1-a to 1-E, the flank wear widths of the regions of the cutting edge corresponding to the positions where the cutting depth of the workpiece was the largest were measured at each time point when the cutting distance reached 1km, 30km, and 60km by performing the above turning. The results are shown in the column "flank wear width (point having maximum cutting depth)" in table 1. The numerical value in the column of "flank wear width (point having the maximum cutting depth)" has a unit of mm. Further, the description of "fracture" in this column indicates that the above-described turning is suspended due to the occurrence of a fracture such as chipping in the region of the cutting edge corresponding to the position where the cutting depth of the workpiece is maximum. It is understood that the smaller the numerical value shown in the column of "flank wear width (point having the maximum cutting depth)" is, the more excellent the wear resistance of the corresponding test piece is in terms of the region of the cutting edge corresponding to the position where the cutting depth of the workpiece is the maximum.

(flank wear width of front cutting edge boundary part)

For each of the turning tools of samples 1-1 to 1-21 and samples 1-a to 1-E, the flank wear width of the tip cutting edge boundary portion of the cutting edge was measured at each time point at which the cutting distance reached 1km, 30km, and 60km by performing the above turning. The results are shown in the column "flank wear width (end cutting edge boundary portion)" in table 1. The numerical value in the column of "flank wear width (front cutting edge boundary portion)" has a unit of mm. Further, the description of "fracture" in this column indicates that the above-described turning is suspended due to the occurrence of fracture such as chipping in the front cutting edge boundary portion of the cutting edge. It is understood that the smaller the numerical value shown in the column of "flank wear width (front cutting edge boundary portion)", the more excellent the wear resistance of the corresponding test piece in the front cutting edge boundary portion of the cutting edge.

(Burr formation distance)

For each of the turning tools of samples 1-1 to 1-21 and samples 1-a to 1-E, the cutting distance (km) was measured at the time point when a burr (height 0.1mm) was formed as it exited from the interrupted portion during turning. The results are shown in table 1 under the heading "burr formation". The symbol "-" in the column of "formation of burr" indicates that no burr having a height of 0.1mm or more was formed at the time point when the cutting distance was more than 60 km. It will be appreciated that the larger the values indicated in the column "burr formation", the smoother the finished surface obtained by the corresponding test piece. It should also be understood that the sample described by the symbol "-" in the column "burr formation" can give the workpiece a smooth finished surface.

From table 1, it is understood that the values of the surface roughness (Ra) of the workpieces obtained by the respective turning tools of samples 1-1 to 1-21 are smaller than those of the workpieces obtained by the respective turning tools of samples 1-a to 1-E. That is, each of the turning tools of samples 1-1 to 1-21 can obtain a smooth finished surface of the workpiece. Further, from the viewpoint of the value of the flank wear width of the region of the cutting edge corresponding to the position where the cutting depth of the workpiece is the largest and the value of the flank wear width of the front cutting edge boundary portion, it can be understood that each of the turning tools of samples 1-1 to 1-21 has wear resistance capable of turning under severe conditions.

< example 2>

< production of cutting edge part comprising CVD Single Crystal Diamond >

By using the same method as in example 1 described above, a cutting edge portion composed of CVD single crystal diamond was manufactured. In example 2, for the cutting test described below, a total of 26 cutting edge portions of samples 2-1 to 2-21 and samples 2-a to 2-E shown in table 1 were prepared.

However, in example 2, for each cutting edge portion of samples 2-1 to 2-21 and samples 2-a to 2-E, the radius of curvature of the nose curved portion in grinding and polishing the growth layer (CVD single crystal diamond) to obtain the cutting edge portion is as shown in table 2. Further, the angle at the intersection between the direction of the intersection line between the rake face and the bisected section of the apex angle of the nose bent portion and the <100> direction of the CVD single crystal diamond at the cutting edge portion described above is shown as "deflection angle" in table 2.

That is, the column of "deflection angle" in table 2 shows the angle at which the direction of the intersection line between the rake face and the bisected section of the apex angle of the nose curved portion and the <100> direction of the CVD single crystal diamond intersect with each other. In table 2, the unit of "radius of curvature" of the blade edge curved portion is mm. The apex angle of the point bent portion of each cutting edge portion of samples 2-1 to 2-21 and samples 2-a to 2-E was 60 °.

< production of turning tool >

Turning tools of samples 2-1 to 2-21 and samples 2-a to 2-E were respectively produced by using the same method as in example 1 described above. The turning tools of samples 2-1 to 2-21 correspond to examples of the present disclosure, and the turning tools of samples 2-a to 2-E correspond to comparative examples.

< cutting test >

The same cutting test as in example 1 was performed for each turning tool of samples 2-1 to 2-21 and samples 2-a to 2-E. The evaluation thereof was also performed in the same manner as in example 1. The results are shown in FIG. 2.

From table 2, it can be understood that the values of the surface roughness (Ra) of the workpieces obtained by the respective turning tools of samples 2-1 to 2-21 are smaller than those of the workpieces obtained by the respective turning tools of samples 2-a to 2-E. That is, each of the turning tools of samples 2-1 to 2-21 can obtain a smooth finished surface of the workpiece. Further, from the viewpoint of the value of the flank wear width of the region of the cutting edge corresponding to the position where the cutting depth of the workpiece is the largest and the value of the flank wear width of the front cutting edge boundary portion, it is understood that each of the turning tools of samples 2-1 to 2-21 has wear resistance capable of turning under severe conditions.

< example 3>

< production of cutting edge part comprising CVD Single Crystal Diamond >

By using the same method as in example 1, a cutting edge portion composed of CVD single crystal diamond was manufactured. In example 3, for the cutting test described below, a total of 8 cutting edge portions of samples 3-1 to 3-8 were produced.

However, in example 3, nitrogen (N) in the atmosphere when the microwave plasma CVD method was performed was adjusted₂) The contents of nitrogen atoms in the cutting edge portions (CVD single crystal diamonds) of the samples 3-1 to 3-8 were as shown in Table 3. The content of nitrogen atoms was determined by SIMS.

Further, for each cutting edge portion of samples 3-1 and 3-2 and samples 3-5 and 3-6, in grinding and polishing the growth layer (CVD single crystal diamond) to obtain the cutting edge portion, the direction of the intersection line between the rake face and the bisected section of the apex angle of the nose bent portion coincides with the <110> direction of the CVD single crystal diamond (the skew angle is 0 °). For each cutting edge portion of samples 3-3 and 3-4 and samples 3-7 and 3-8, the direction of the intersection line between the rake face and the bisected section of the apex angle of the nose bent portion coincides with the <100> direction of the CVD single crystal diamond (the skew angle is 0 °). The laue photographic method described above was used to determine the crystal orientation of CVD single crystal diamond. Further, the apex angle of the bent portion of the cutting edge was 60 ° for each of the cutting edge portions of samples 3-1 to 3-8.

< production of turning tool >

Turning tools of samples 3-1 to 3-8 were produced by using the same method as in example 1.

< cutting test >

Cutting tests were conducted on each of the turning tools of samples 3-1 to 3-8 to evaluate fracture resistance. Specifically, the turning tool is attached to the turntable of the NC lathe. On the other hand, a cylindrical workpiece was fixed to a chuck of an NC lathe, and turning was performed under the following cutting conditions. In this turning, the clearance angle is set to 7 °. Thus, the fracture resistance was evaluated according to the following evaluation method. In example 3, the following fracture resistance evaluation was also performed on each of the turning tools of the above-described samples 1-1 and 2-1.

(cutting conditions)

Workpiece: aluminium alloy A390 (eight discontinuous grooves)

Cutting speed (Vc): 800 m/min

Cut amount (ap): 0.3mm

Feed amount (f): 0.3mm/rev

Material of cutting oil: 2% by mass of a water-soluble emulsion

< evaluation >

(fracture resistance)

As the evaluation of fracture resistance, the cutting distance (in km) at which the above turning can be performed was measured until a defect of 0.02mm or more occurred in the cutting edge portion of each of the turning tools of samples 1-1, 2-1 and 3-1 to 3-8. It is understood that the fracture resistance of the test specimen is more excellent when the test specimen obtains a longer working distance. The results are shown in Table 3.

[ Table 3]

From table 3, it is understood that the turning tools of respective samples 1-1, 2-1 and 3-1 to 3-4 in which the content of nitrogen atoms contained in the CVD single crystal diamond is 1ppm or more and 100ppm or less exhibit more excellent fracture resistance than the turning tools of respective samples 3-5 to 3-8 in which the content of nitrogen atoms falls outside the above range.

< example 4>

< production of cutting edge part comprising CVD Single Crystal Diamond >

By using the same method as in example 1, a cutting edge portion composed of CVD single crystal diamond was manufactured. In example 4, for the cutting test described below, a total of 2 cutting edge portions of sample 4-1 and sample 4-2 were made.

However, in example 4, for each cutting edge portion of samples 4-1 and 4-2, the apex angle in grinding and polishing the growth layer (CVD single crystal diamond) to obtain the cutting edge portion is as shown in table 4. In addition, with respect to each cutting edge portion of samples 4-1 and 4-2, the direction of the intersection line between the rake face and the bisected section of the apex angle of the nose bent portion coincides with the <110> direction of the CVD single crystal diamond (the skew angle is 0 °). The laue photographic method described above was used to determine the crystal orientation of CVD single crystal diamond.

< production of turning tool >

By using the same method as in example 1, each turning tool of samples 4-1 and 4-2 was produced.

< cutting test >

The cutting tests were carried out on each of the turning tools of samples 4-1 and 4-2 under the same cutting conditions as in example 1 except that the turning was carried out at the relief angles shown in table 4. Specifically, for samples 4-1 and 4-2, the same radius of curvature, feed amount, skew angle, and cutting condition as for samples 1-10 were used, respectively. However, in the evaluation of each of the turning tools of samples 4-1 and 4-2, the surface roughness (Ra), the flank wear width at the region of the cutting edge corresponding to the position where the cutting depth of the workpiece is the largest, and the flank wear width at the front cutting edge boundary portion of the cutting edge were measured only at the time point when the cutting distance reached 60km by performing the above turning. Further, the cutting distance (km) at the time point when the burr having a height of 0.1mm or more was formed was measured. The results are shown in Table 4.

[ Table 4]

From table 4, it is understood that each of the turning tools of samples 4-1 and 4-2 has a small surface roughness (Ra) value. That is, each of the turning tools of samples 4-1 and 4-2 can obtain a smooth finished surface of the workpiece. Further, from the viewpoint of the value of the flank wear width at the region of the cutting edge corresponding to the position where the cutting depth of the workpiece is the largest and the value of the flank wear width at the front cutting edge boundary portion, it can be understood that each of the turning tools of samples 4-1 and 4-2 has wear resistance capable of turning under severe conditions.

So far, the embodiments and examples of the present disclosure have been explained, but it is originally intended to appropriately combine the configurations of the embodiments and examples.

The embodiments disclosed herein are illustrative and not restrictive in any respect. The scope of the present invention is defined by the terms of the claims, rather than the embodiments described above, and is intended to include any modifications within the meaning and scope equivalent to the terms of the claims.

List of reference numerals

1: turning a tool; 2: a substrate; 3: a cutting edge part; 4: a rake face; 5: a flank face; 6: a cutting edge; 8: chamfering; 10: a blade bar part; z: and (5) a workpiece.