Cutting Tools

Abstract

To provide a cutting tool capable of forming a cutting edge at a lower cost without shortening the life of the cutting tool. [Solution] The cutting tool includes a base metal with a seat portion, a cutting edge member that is a polycrystalline diamond sintered body containing polycrystalline diamond and a binder, and a brazing material that secures the cutting edge member to the seat portion of the base metal. The base metal includes an upper surface, a lower surface, and a side surface connected to the upper and lower surfaces. The seat portion includes a bottom seat surface that slopes back from the upper surface toward the lower surface and is connected to the side surface. The cutting edge member includes a rake face extending along the upper surface, a bottom seat surface opposite the rake face, a flank face connected to the rake face and the bottom seat surface, and a cutting edge formed between the rake face and the flank face. The cutting edge member has a thickness of 0.3 mm or more. The brazing material is disposed between the bottom seat surface and the bottom seat surface and is in contact with the bottom seat surface and the bottom seat surface. The flank face is located outside the base metal relative to the side surface of the base metal.

Description

[Technical field]

[0001] The present disclosure relates to cutting tools and methods of manufacturing same. [Background technology]

[0002] Patent Document 1 (JP Patent Publication 10-193203A) discloses a throw-away insert including a base metal having a recess formed therein and a cutting blade member brazed to the recess. The cutting blade member is a layered sintered body in which a backing plate made of cemented carbide and an ultra-high hardness sintered body mainly composed of diamond or cubic boron nitride (CBN) are laminated. The backing plate is brazed to the recess of the base metal, whereby the cutting blade member is fixed to the recess of the base metal. The cutting blade member includes a rake face, a flank face, and a cutting blade formed on the intersection ridge between the rake face and the flank face. The flank face of the cutting blade member protrudes from the flank face of the base metal. The cutting blade is formed by grinding the flank face of the cutting blade member with a grindstone. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 10-193203 Summary of the Invention

[0004] A cutting tool according to one embodiment of the present disclosure includes a base metal having a seat portion, a cutting edge member which is a polycrystalline diamond sintered body containing polycrystalline diamond and a binder, and a brazing material for fixing the cutting edge member to the seat portion of the base metal. The base metal includes an upper surface, a lower surface, and a side surface connected to the upper surface and the lower surface. The seat portion includes a seat bottom surface and a seat wall. The seat bottom surface is recessed from the upper surface toward the lower surface and is connected to the side surface. The seat wall is connected to the upper surface, the seat bottom surface, and the side surface. The cutting edge member includes a rake surface extending along the upper surface, a cutting edge bottom surface opposite to the rake surface, a flank surface connected to the rake surface and the cutting edge bottom surface, and a cutting edge formed between the rake surface and the flank surface. The thickness of the cutting edge member is 0.3 mm or more. The brazing material is disposed between the cutting edge bottom surface and the seat bottom surface, and is in contact with the cutting edge bottom surface and the seat bottom surface. The flank surface is located outside the base metal relative to the side surface of the base metal.

[0005] The method for manufacturing a cutting tool according to one aspect of the present disclosure includes a step of fixing a cutting edge sintered body to a seat of a base metal with a brazing material. The cutting edge sintered body is a polycrystalline diamond sintered body containing polycrystalline diamond and a binder, and includes a rake face, a cutting edge bottom face, and a flank face. The method for manufacturing a cutting tool according to one aspect of the present disclosure includes a step of irradiating a laser beam along the flank face of the cutting edge sintered body to laser process the flank face of the cutting edge sintered body, thereby forming a cutting edge.

[0006] A method for manufacturing a cutting tool according to an embodiment of the present disclosure includes a step of fixing a cutting edge sintered body to a seat of a base metal with a brazing material. The cutting edge sintered body is a polycrystalline diamond sintered body containing polycrystalline diamond and a binder, and includes a rake face, a cutting edge bottom face, and a flank face. A method for manufacturing a cutting tool according to an embodiment of the present disclosure includes a step of irradiating a laser beam along the flank face of the cutting edge sintered body and laser processing the flank face of the cutting edge sintered body under a first laser irradiation condition to form a cutting edge. A method for manufacturing a cutting tool according to an embodiment of the present disclosure includes a step of irradiating a laser beam along the flank face and laser processing the flank face under a second laser irradiation condition different from the first laser irradiation condition to generate at least one of graphite and cobalt oxide on the flank face. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic perspective view of a cutting tool according to an embodiment. [Diagram 2] FIG. 2 is a schematic front view of the cutting tool according to the embodiment. [Diagram 3] FIG. 3 is a schematic partially enlarged front view of a region III shown in FIG. 2 of the cutting tool according to the embodiment. [Figure 4] FIG. 4 is a schematic enlarged partial rear view of the cutting tool according to the embodiment. [Diagram 5] FIG. 5 is a schematic enlarged partial cross-sectional view of the cutting tool of the embodiment taken along the cross-sectional line VV shown in FIG. [Figure 6] FIG. 6 is a schematic partially enlarged cross-sectional view of a cutting tool according to another aspect of the embodiment. [Figure 7] FIG. 7 is a flowchart illustrating an example of a method for manufacturing a cutting tool according to an embodiment. [Figure 8] FIG. 8 is a schematic partially enlarged cross-sectional view showing a step of an example of a method for manufacturing the cutting tool of the embodiment. [Figure 9] FIG. 9 is a flowchart illustrating an example of a method for remanufacturing a cutting tool according to an embodiment. [Figure 10] FIG. 10 is a schematic enlarged partial cross-sectional view of a cutting tool according to an embodiment in which a chip has occurred in the cutting edge member. [Figure 11] FIG. 11 is a schematic partially enlarged cross-sectional view showing a step of the method for remanufacturing the cutting tool according to the embodiment. [Figure 12] FIG. 12 is a flowchart illustrating another example of a manufacturing method for the cutting tool according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] [Problem that this disclosure aims to solve] In the throw-away tip disclosed in Patent Document 1, the cutting edge member includes an ultra-high hardness sintered body and a backing plate. The cutting edge is formed by grinding the flank of the cutting edge member with a grindstone. Therefore, in order to form the cutting edge, it is necessary to grind not only the ultra-high hardness sintered body but also the backing plate on which the cutting edge is not formed. In addition, a grindstone is required for manufacturing the throw-away tip. As a result, the manufacturing time of the throw-away tip is extended, and the manufacturing cost of the throw-away tip increases. The object of the present disclosure is to provide a cutting tool in which a cutting edge can be formed at a lower cost without shortening the life of the cutting tool.

[0009] [Effects of this disclosure] According to the cutting tool of the present disclosure, cutting edges can be formed at lower cost without shortening the life of the cutting tool.

[0010] [Overview of the embodiment] The embodiments of the present disclosure will be listed and described.

[0011] (1) The cutting tool 1 according to the present disclosure includes a base metal 10 having a seat portion 15, a cutting edge member 20 which is a polycrystalline diamond sintered body containing polycrystalline diamond and a binder, and a brazing material 30 which fixes the cutting edge member 20 to the seat portion 15 of the base metal 10. The base metal 10 includes an upper surface 11, a lower surface 12, and a side surface 13 which is connected to the upper surface 11 and the lower surface 12. The seat portion 15 includes a seat bottom surface 16 and a seat wall 17. The seat bottom surface 16 is recessed from the upper surface 11 toward the lower surface 12, and is connected to the side surface 13. The seat wall 17 is connected to the upper surface 11, the seat bottom surface 16, and the side surface 13. The cutting edge member 20 includes a rake face 21 extending along the upper surface 11, a cutting edge bottom surface 22 opposite to the rake face 21, a flank face 23 connected to the rake face 21 and the cutting edge bottom surface 22, and a cutting edge 25 formed between the rake face 21 and the flank face 23. The thickness h of the cutting edge member 20 is 0.3 mm or more. The brazing material 30 is disposed between the cutting edge bottom surface 22 and the seat bottom surface 16, and is in contact with the cutting edge bottom surface 22 and the seat bottom surface 16. The flank face 23 is located outside the base metal 10 with respect to the side surface 13 of the base metal 10.

[0012] In the cutting tool 1 of the present disclosure, the cutting edge member 20 is a polycrystalline diamond sintered body containing polycrystalline diamond and a binder, and the brazing material 30 is disposed between the cutting edge bottom surface 22 and the seat bottom surface 16, and is in contact with the cutting edge bottom surface 22 and the seat bottom surface 16. In other words, the cutting edge member 20 does not include a backing plate. In addition, the flank surface 23 is located outside the base metal 10 with respect to the side surface 13 of the base metal 10. Therefore, the cutting edge 25 can be formed in a shorter time by laser processing the flank surface 23 without a grindstone. The cutting edge 25 can be formed at a lower cost.

[0013] The cutting edge 25 can be formed without laser processing the backing plate. Therefore, melting of the brazing material 30 caused by laser processing of the backing plate can be prevented. Furthermore, since the thickness h of the cutting edge member 20 is 0.3 mm or more, the distance between the cutting edge 25 and the brazing material 30 is increased. Melting of the brazing material 30 caused by heat generated at the cutting edge 25 when cutting a workpiece using the cutting tool 1 can be prevented. Thus, shortening of the life of the cutting tool 1 can be prevented.

[0014] Moreover, the polycrystalline diamond sintered body contains a binder. The binder allows the polycrystalline diamond to be sintered at a low cost. Therefore, the cost of the cutting tool 1 can be reduced. The binder improves the wear resistance of the cutting edge member 20. Therefore, the wear resistance of the cutting tool 1 can be improved. The binder increases the absorption rate of the polycrystalline diamond sintered body with respect to the laser beam 36 during laser processing. Therefore, the cutting edge 25 can be easily formed by laser processing.

[0015] (2) In the cutting tool 1 according to (1) above, the first extension surface 23b of the flank surface 23 from the cutting edge bottom surface 22 to the lower surface 12 side of the base metal 10 is spaced apart from the side surface 13 of the base metal 10.

[0016] Therefore, the laser beam 36 for forming the cutting edge 25 is irradiated onto the flank 23 without irradiating onto the base metal 10. The cutting edge 25 can be formed at a lower cost.

[0017] (3) In the cutting tool 1 according to (1) or (2) above, a recessed structure 28 is formed on at least one of the cutting edge bottom surface 22 or the seat bottom surface 16. The brazing material 30 is filled in at least a part of the recessed structure 28.

[0018] This increases the fixing strength of the cutting edge member 20 to the base metal 10. This increases the life of the cutting tool 1.

[0019] (4) In the cutting tool 1 according to any one of (1) to (3) above, the protruding length t of the flank 23 from the side surface 13 is 0.01 mm or more.

[0020] Therefore, it is possible to easily avoid irradiation of the base metal 10 with the laser beam 36 for forming the cutting edge 25. The cutting edge 25 can be formed at a lower cost.

[0021] (5) In the cutting tool 1 according to the above (4), the protruding length t of the flank 23 is 0.50 mm or less.

[0022] Therefore, the rigidity of the cutting edge member 20 is prevented from decreasing. When cutting a workpiece using the cutting tool 1, chipping of the cutting edge 25 can be prevented. When cutting a workpiece using the cutting tool 1, sudden damage to the cutting tool 1 can be prevented. The life of the cutting tool 1 can be prevented from being shortened.

[0023] (6) In the cutting tool 1 according to any one of (1) to (5) above, the thickness h of the cutting edge member 20 is 2.0 mm or less.

[0024] This makes it possible to reduce the amount of polycrystalline diamond sintered body used to form the cutting edge member 20. The cost of the cutting tool 1 can be reduced.

[0025] (7) In the cutting tool 1 according to any one of (1) to (6) above, the polycrystalline diamond sintered body contains at least one of graphite and cobalt oxide on the flank 23.

[0026] Graphite has lubricity. Therefore, when the flank 23 contains graphite, the cutting tool 1 has excellent lubricity capable of dealing with initial wear. The wear resistance of the cutting tool 1 can be improved. Cobalt oxide improves the wear resistance of the flank 23. Therefore, when the flank 23 contains cobalt oxide, the wear resistance of the cutting tool 1 can be improved.

[0027] (8) In the cutting tool 1 according to (7) above, when carbon constituting the polycrystalline diamond is defined as first carbon, carbon constituting the graphite is defined as second carbon, and Raman spectroscopy is performed on the flank 23, the ratio of the second peak intensity to the sum of the first peak intensity of the first carbon on the flank 23 and the second peak intensity of the second carbon on the flank 23 is 0.01 or more and 0.50 or less. The volume average diameter of the polycrystalline diamond is 10 μm or more.

[0028] The ratio of the lubricating graphite is 0.01 or more. Therefore, the cutting tool 1 has excellent lubricity capable of dealing with initial wear. The wear resistance of the cutting tool 1 can be improved. Since the ratio of graphite in the flank 23 is 0.50 or less, the ratio of polycrystalline diamond having a higher hardness than graphite in the flank 23 is equal to or greater than the ratio of graphite. Therefore, the hardness of the flank 23 can be prevented from being excessively reduced. Since the volume average diameter of the polycrystalline diamond is 10 μm or more, the polycrystalline diamond is prevented from being excessively converted to graphite during laser processing of the flank 23. Therefore, the hardness of the flank 23 can be prevented from being excessively reduced. In this way, the wear resistance of the cutting tool 1 can be improved.

[0029] (9) In the cutting tool 1 according to the above (7) or (8), the polycrystalline diamond sintered body contains 25% by weight or more of cobalt oxide on the flank 23.

[0030] Therefore, the wear resistance of the flank 23 can be further improved, and the wear resistance of the cutting tool 1 can be further improved.

[0031] (10) The manufacturing method of cutting tool 1 according to a first aspect of the present disclosure relating to any one of (1) to (9) above includes a step (S2) of fixing sintered cutting edge body 20p to seat portion 15 of base metal 10 with brazing material 30. Sintered cutting edge body 20p is a polycrystalline diamond sintered body containing polycrystalline diamond and a binder, and includes rake face 21, cutting edge bottom surface 22, and flank 23. The manufacturing method of cutting tool 1 according to the present disclosure includes a step (S4) of forming cutting edge 25 by irradiating laser beam 36 along flank 23 of sintered cutting edge body 20p to laser process flank 23 of sintered cutting edge body 20p.

[0032] The cutting edge sintered body 20p is a polycrystalline diamond sintered body, and the brazing material 30 is disposed between the cutting edge bottom surface 22 and the seat bottom surface 16, and is in contact with the cutting edge bottom surface 22 and the seat bottom surface 16. In other words, the cutting edge sintered body 20p does not include a backing plate. In addition, the flank surface 23 is located outside the base metal 10 with respect to the side surface 13 of the base metal 10. Therefore, the cutting edge 25 can be formed in a shorter time by laser processing the flank surface 23 without a grindstone. The cutting edge 25 can be formed at a lower cost.

[0033] The cutting edge 25 can be formed without laser processing the backing plate. Therefore, melting of the brazing material 30 caused by laser processing of the backing plate can be prevented. Furthermore, since the thickness h of the cutting edge member 20 is 0.3 mm or more, the distance between the cutting edge 25 and the brazing material 30 is increased. Melting of the brazing material 30 caused by heat generated at the cutting edge 25 when cutting a workpiece using the cutting tool 1 can be prevented. Thus, shortening of the life of the cutting tool 1 can be prevented.

[0034] Moreover, the polycrystalline diamond sintered body includes a binder. The binder enables the polycrystalline diamond to be sintered at a low cost. The cost of the cutting tool 1 can be reduced. The binder improves the wear resistance of the cutting edge member 20. Therefore, the wear resistance of the cutting tool 1 can be improved. The binder increases the absorption rate of the polycrystalline diamond sintered body with respect to the laser beam 36 when forming the cutting edge 25 by laser processing. Therefore, the cutting edge 25 can be easily formed by laser processing.

[0035] (11) The manufacturing method of the cutting tool 1 according to the second aspect of the present disclosure, which relates to any one of the above (7) to (9), includes a step (S2) of fixing the cutting edge sintered body 20p to the seat 15 of the base metal 10 with the brazing material 30. The cutting edge sintered body 20p is a polycrystalline diamond sintered body containing polycrystalline diamond and a binder, and includes a rake face 21, a cutting edge bottom face 22, and a flank face 23. The manufacturing method of the cutting tool 1 according to the present disclosure includes a step (S4) of forming a cutting edge 25 by irradiating the laser beam 36 along the flank face 23 of the cutting edge sintered body 20p and laser processing the flank face 23 of the cutting edge sintered body 20p under a first laser irradiation condition. The manufacturing method of the cutting tool 1 according to the present disclosure includes a step (S5) of generating at least one of graphite and cobalt oxide on the flank face 23 by irradiating the laser beam 36 along the flank face 23 and laser processing the flank face 23 under a second laser irradiation condition different from the first laser irradiation condition.

[0036] The method for manufacturing cutting tool 1 according to the second aspect of the present disclosure has the following effects in addition to the effects of the method for manufacturing cutting tool 1 according to the first aspect of the present disclosure related to (10) above. Graphite has lubricity. Therefore, when graphite is generated on flank 23, cutting tool 1 has excellent lubricity capable of dealing with initial wear. The wear resistance of cutting tool 1 can be improved. Cobalt oxide improves the wear resistance of flank 23. Therefore, when cobalt oxide is generated on flank 23, the wear resistance of cutting tool 1 can be improved.

[0037] The polycrystalline diamond sintered body also contains a binder. The binder increases the absorption rate of the polycrystalline diamond sintered body with respect to the laser beam 36 when at least one of graphite and cobalt oxide is generated by laser processing. Therefore, at least one of graphite and cobalt oxide can be generated in a larger amount on the flank surface 23 by laser processing under the second laser irradiation conditions.

[0038] [Details of the embodiment] The details of the embodiment will be described below with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals, and the description thereof will not be repeated.

[0039] A cutting tool 1 of the present embodiment will be described with reference to FIGS.

[0040] The cutting tool 1 includes a base metal 10 , a cutting edge member 20 , and a brazing material 30 .

[0041] The base metal 10 is made of, for example, a cemented carbide. The base metal 10 is obtained by mixing and sintering a cemented carbide powder such as a tungsten carbide (WC) powder and a binder powder such as a cobalt powder. The base metal 10 includes an upper surface 11, a lower surface 12, and a side surface 13 connected to the upper surface 11 and the lower surface 12. As shown in FIG. 1 to FIG. 5, the angle α of the side surface 13 with respect to the lower surface 12 may be greater than 90°, and the side surface 13 may be a positive type side surface. As shown in FIG. 6, the angle α of the side surface 13 with respect to the lower surface 12 may be less than 90°, and the side surface 13 may be a negative type side surface.

[0042] The shape of the base metal 10 in plan view from the upper surface 11 of the base metal 10 is, for example, an equilateral triangle. The shape of the base metal 10 in plan view from the upper surface 11 of the base metal 10 is not particularly limited, and may be a polygon such as a rhombus, a regular pentagon, or a regular hexagon. The base metal 10 may be provided with a through hole 19 extending from the upper surface 11 to the lower surface 12. In order to hold the base metal 10 with a holder, a locking member (not shown) of a holder (not shown) that fixes the cutting tool 1 when the cutting tool 1 is used for cutting processing is locked in the through hole 19.

[0043] The base metal 10 is provided with a seat 15. The seat 15 includes a bottom seat surface 16 and a seat wall 17. The bottom seat surface 16 is recessed from the upper surface 11 toward the lower surface 12, and is connected to the side surface 13. The seat wall 17 is connected to the upper surface 11, the bottom seat surface 16, and the side surface 13. The seat 15 is provided, for example, at least one of the multiple corners of the base metal 10. The seat 15 may be provided, for example, at two or more of the multiple corners of the base metal 10, or may be provided at all of the multiple corners of the base metal 10.

[0044] The cutting edge member 20 is a polycrystalline diamond (PCD) sintered body containing polycrystalline diamond and a binder. The binder contains, for example, cobalt. The binder allows polycrystalline diamond to be sintered at low cost. Therefore, the cost of the cutting tool 1 can be reduced. The binder improves the wear resistance of the cutting edge member 20. Therefore, the wear resistance of the cutting tool 1 can be improved. The PCD sintered body is obtained by mixing and sintering, for example, diamond crystal powder and binder powder containing cobalt powder. The cutting edge member 20 does not include a backing plate.

[0045] The volume mean diameter of the polycrystalline diamond is, for example, 10 μm or more. The volume mean diameter of the polycrystalline diamond is obtained as follows.

[0046] The flank 23 is polished to expose a surface 100 μm away from the flank 23. This exposed surface is parallel to the flank 23. Graphite and cobalt oxide, which will be described later, are not formed on this exposed surface. A scanning electron microscope (SEM) is used to obtain backscattered electron images of multiple fields (for example, five or more fields) of the exposed surface. The black areas in the backscattered electron images are areas where polycrystalline diamond particles exist. Each of the black areas corresponds to each of the polycrystalline diamond particles. The white or gray areas in the backscattered electron images are areas where the binder exists. Image analysis software is used to calculate the circle-equivalent diameter of each of the black areas in the backscattered electron images of each of the multiple fields. The circle-equivalent diameter means the diameter of a circle having the same area as the area of ​​each of the black areas. Each of the black areas is considered to have the volume of a sphere with the circle-equivalent diameter as its diameter, and the volume of each of the black areas is calculated. For each of the multiple fields, the volume-average diameter is calculated from the circle-equivalent diameter and volume of the black area. The average value of the volume mean diameters of the multiple fields of view is calculated as the volume mean diameter of the polycrystalline diamond.

[0047] The cutting edge member 20 includes a rake face 21, a cutting edge bottom surface 22 opposite to the rake face 21, a clearance surface 23 connected to the rake face 21 and the cutting edge bottom surface 22, and a cutting edge side surface 24.

[0048] The rake face 21 extends along the upper surface 11. In this specification, the rake face 21 extending along the upper surface 11 means that the main extension direction of the rake face 21 is the same as the main extension direction of the upper surface 11. Specifically, the main extension direction of the rake face 21 and the main extension direction of the upper surface 11 are both in the direction into the plane of the paper. The rake face 21 extending along the upper surface 11 includes both the rake face 21 being flush with the upper surface 11 and the rake face 21 not being flush with the upper surface 11. The rake face 21 extending along the upper surface 11 includes both the rake face 21 being parallel to the upper surface 11 and the rake face 21 not being parallel to the upper surface 11.

[0049] As shown in Figures 1 to 5, the angle β of the flank 23 with respect to the cutting edge bottom surface 22 may be greater than 90°, and the flank 23 may be a positive flank 23. As shown in Figure 6, the angle β of the flank 23 with respect to the cutting edge bottom surface 22 may be less than 90°, and the flank 23 may be a negative flank 23. The cutting edge side surface 24 faces the seat wall 17 and is connected to the rake face 21 and the cutting edge bottom surface 22. The cutting edge side surface 24 may be further connected to the flank 23.

[0050] The cutting edge member 20 further includes a cutting edge 25 formed between the rake face 21 and the flank 23. The cutting edge 25 is not particularly limited, but is, for example, a ridge defined by the rake face 21 and the flank 23. The cutting edge 25 may be formed, for example, by chamfering the ridge defined by the rake face 21 and the flank 23.

[0051] The thickness h of the cutting edge member 20 is 0.3 mm or more. The thickness h of the cutting edge member 20 is defined as the shortest distance between the cutting edge 25 and the cutting edge bottom surface 22 in the normal direction of the cutting edge bottom surface 22. Since the thickness h of the cutting edge member 20 is 0.3 mm or more, the distance between the cutting edge 25 and the brazing material 30 increases. The brazing material 30 can be prevented from melting due to heat generated at the cutting edge 25 when cutting a workpiece using the cutting tool 1. The life of the cutting tool 1 can be prevented from being shortened. The thickness h of the cutting edge member 20 may be 0.4 mm or more, or may be 0.5 mm or more. The thickness h of the cutting edge member 20 may be 2.0 mm or less. Therefore, the amount of polycrystalline diamond sintered body constituting the cutting edge member 20 can be reduced. The cost of the cutting tool 1 can be reduced. The thickness h of the cutting edge member 20 may be 1.5 mm or less.

[0052] The flank 23 is located outside the base metal 10 with respect to the side surface 13 of the base metal 10. Therefore, the cutting edge 25 is also located outside the base metal 10 with respect to the side surface 13 of the base metal 10. With reference to Figures 5 and 6, a first extension surface 23b of the flank 23 from the cutting edge bottom surface 22 to the lower surface 12 of the base metal 10 is separated from the side surface 13 of the base metal 10. Therefore, the laser beam 36 (see Figures 8 and 11) for forming or regenerating the cutting edge 25 is irradiated to the flank 23 without being irradiated to the base metal 10.

[0053] 5 and 6, the protruding length t of the flank 23 from the side surface 13 is 0.01 mm or more. The protruding length t of the flank 23 is defined as the shortest distance between the second extension surface 13b of the side surface 13 from the side surface 13 or the seat bottom surface 16 to the upper surface 11 of the base metal 10 and the ridge line 27 of the cutting edge member 20 defined by the cutting edge bottom surface 22 and the flank 23. That is, the protruding length t of the flank 23 is defined as the length of the perpendicular line 13c drawn from the ridge line 27 of the cutting edge member 20 to the side surface 13 or the second extension surface 13b of the side surface 13. Therefore, it is possible to easily prevent the laser beam 36 (see FIG. 8 and FIG. 11) for forming or regenerating the cutting edge 25 from being irradiated to the base metal 10. The protruding length t of the flank 23 may be 0.05 mm or more, or may be 0.10 mm or more. The protruding length t of the flank 23 may be 0.50 mm or less. Therefore, the rigidity of the cutting edge member 20 is prevented from decreasing. When cutting a workpiece using the cutting tool 1, chipping of the cutting edge 25 can be prevented. When cutting a workpiece using the cutting tool 1, sudden damage to the cutting tool 1 can be prevented. The life of the cutting tool 1 can be prevented from being shortened.

[0054] The concave structure 28 is formed on the cutting edge bottom surface 22. Therefore, the fixing strength of the cutting edge member 20 to the base metal 10 is increased. The concave structure 28 may be, for example, a linear groove extending along the cutting edge bottom surface 22, or may be a dot-shaped groove. The depth of the groove is, for example, about 10 μm. Specifically, the concave structure 28 may be a plurality of linear grooves arranged in a lattice pattern. The plurality of linear grooves are formed at a pitch of, for example, about 0.1 mm. The concave structure 28 may be formed on the seat bottom surface 16 of the base metal 10, or may be formed on both the cutting edge bottom surface 22 and the seat bottom surface 16.

[0055] The concave structure 28 may be further formed on the cutting edge side surface 24. This increases the fixing strength of the cutting edge member 20 to the base metal 10. The concave structure 28 may be, for example, a linear groove extending along the cutting edge side surface 24, or may be a dot-shaped groove. The concave structure 28 may be further formed on the seat wall 17 of the base metal 10, or may be further formed on both the cutting edge side surface 24 and the seat wall 17.

[0056] The polycrystalline diamond sintered body may include at least one of graphite and cobalt oxide on the flank 23. In this specification, at least one of graphite and cobalt oxide means graphite, cobalt oxide, or graphite and cobalt oxide. The cutting edge member 20 may be, for example, a polycrystalline diamond (PCD) sintered body including polycrystalline diamond, a binder, and graphite. The cutting edge member 20 may be, for example, a PCD sintered body including polycrystalline diamond, cobalt oxide, and a binder. The cutting edge member 20 may be, for example, a PCD sintered body including polycrystalline diamond, cobalt oxide, graphite, and a binder.

[0057] Graphite has lubricating properties. Therefore, when the flank 23 contains graphite, the cutting tool 1 has excellent lubricating properties capable of dealing with initial wear. The wear resistance of the cutting tool 1 (flank 23) can be improved.

[0058] The ratio of graphite on the flank 23 is, for example, 0.01 or more and 0.50 or less. Since the ratio of graphite having lubricity is 0.01 or more, a cutting tool 1 having excellent lubricity capable of dealing with initial wear can be provided. The ratio of graphite may be 0.05 or more and less than 0.50, or 0.10 or more and 0.48 or less. In this specification, the ratio of graphite on the flank 23 is defined as the ratio of graphite to the sum of PCD and graphite on the flank 23. The ratio of graphite on the flank 23 is obtained by the following method.

[0059] A Raman spectroscopic analysis is performed by irradiating the flank surface 23 with a laser having a wavelength of 532 nm as excitation light at room temperature. -1 A phonon peak is obtained by analyzing the Raman spectrum using a spectrometer (trade name LabRAM HR UV-VIS NIR, manufactured by Horiba, Ltd.) having the following wave number resolution. This phonon peak is fitted by a composite function of a Lorentzian function and a Gaussian function using the least squares method to obtain the first peak intensity (Id) of the first carbon constituting the polycrystalline diamond and the second peak intensity (Ig) of the second carbon constituting the graphite. The first peak of the first carbon constituting the polycrystalline diamond is, for example, at 1333 cm -1 The second peak of the secondary carbon that constitutes graphite appears, for example, in the range of 1400 to 1700 cm -1 appears nearby.

[0060] From the measured Id and Ig, Ig / (Ig+Id) is calculated. Id and Ig are measured at any five points on the exposed surface, and Ig / (Ig+Id) is calculated. The average value of Ig / (Ig+Id) at the five points is calculated as the ratio of graphite on the flank 23.

[0061] Specifically, the polycrystalline diamond sintered body may contain graphite from the flank 23 to a depth of 1 μm. The cutting tool 1 equipped with the cutting edge member 20, which is a polycrystalline diamond sintered body, is applied to the processing of a workpiece that is difficult to cut. The processing of a workpiece that is difficult to cut is called mirror processing, and it is often required to finish the surface of the workpiece to a very small surface roughness. In such cutting processing, when the cutting tool 1 is used to such an extent that the surface located at a depth of 1 μm from the flank 23 is exposed, it is generally determined that the cutting tool 1 has reached the end of its life. Since the cutting edge member 20 is a polycrystalline diamond sintered body containing graphite from the flank 23 to a depth of 1 μm, this lubricity continues until it is determined that the cutting tool 1 has reached the end of its life.

[0062] The cobalt oxide improves the wear resistance of the flank 23. Therefore, when the flank 23 contains cobalt oxide, the wear resistance of the cutting tool 1 can be improved. The polycrystalline diamond sintered body may contain, for example, 25% by weight or more of cobalt oxide on the flank 23. Therefore, the wear resistance of the cutting tool 1 can be improved. The polycrystalline diamond sintered body may contain, for example, 30% by weight or more of cobalt oxide on the flank 23, or may contain 40% by weight or more of cobalt oxide. The polycrystalline diamond sintered body may contain, for example, 60% by weight or less of cobalt oxide on the flank 23. Therefore, the excessive presence of cobalt oxide on the flank 23 can prevent the hardness of the flank 23 from being excessively reduced. The wear resistance of the cutting tool 1 can be improved.

[0063] The weight ratio of cobalt oxide on the flank 23 is obtained as follows: An X-ray diffraction (XRD) pattern is obtained for the flank 23 of the cutting edge member 20, which is a polycrystalline diamond sintered body. The weight ratio of cobalt oxide on the flank 23 is calculated by a reference intensity ratio (RIR) method from the intensity ratio of the peaks corresponding to cobalt oxide in the XRD pattern.

[0064] The cutting edge member 20 is fixed to the seat portion 15 of the base metal 10 by using the brazing material 30. Specifically, the brazing material 30 is disposed between the cutting edge bottom surface 22 and the seat bottom surface 16, and is in contact with the cutting edge bottom surface 22 and the seat bottom surface 16. The brazing material 30 may be further disposed between the cutting edge side surface 24 and the seat wall 17, and may be in contact with the cutting edge side surface 24 and the seat wall 17. The brazing material 30 is, for example, an Ag-Cu-In-Ti based brazing material. The brazing material 30 is filled in at least a part of the concave structure 28. The brazing material 30 may be filled in the entire concave structure 28.

[0065] An example of a method for manufacturing the cutting tool 1 of this embodiment will be described with reference to FIGS.

[0066] The manufacturing method of the cutting tool 1 of this embodiment includes a step (S1) of preparing a cutting edge sintered body 20p. The cutting edge sintered body 20p has a similar configuration to the cutting edge member 20, but differs from the cutting edge member 20 mainly in that the cutting edge 25 is not formed in the cutting edge sintered body 20p. Therefore, the cutting edge sintered body 20p is a polycrystalline diamond (PCD) sintered body containing polycrystalline diamond and a binder. The cutting edge sintered body 20p includes a rake face 21, a cutting edge bottom surface 22, a flank surface 23, and a cutting edge side surface 24. The thickness h of the cutting edge sintered body 20p is 0.3 mm or more.

[0067] The cutting edge sintered body 20p is obtained as follows. A polycrystalline diamond layer is formed on a backing layer (not shown) made of cemented carbide to obtain a laminate of the backing layer and the polycrystalline diamond layer. The polycrystalline diamond layer contains, for example, diamond crystal powder and a binder powder such as cobalt powder. The backing layer contains, for example, cemented carbide powder and a binder powder such as cobalt powder. This laminate is sintered to obtain a laminated sintered body of the backing plate, which is the cemented carbide sintered body layer, and the polycrystalline diamond sintered body layer. The backing plate is ground using a grinding wheel to remove it from the laminated sintered body. A concave structure 28 is formed on the cutting edge bottom surface 22 by, for example, laser processing. The laser light source used for this laser processing is, for example, a Nd:YAG pulsed laser or a YVO 4The laser is a pulse laser. In this manner, the cutting edge sintered body 20p, which is a polycrystalline diamond (PCD) sintered body containing polycrystalline diamond and a binder, is obtained.

[0068] The manufacturing method of the cutting tool 1 of this embodiment includes a step (S2) of fixing the cutting edge sintered body 20p to the seat portion 15 of the base metal 10 with the brazing material 30. The brazing material 30 is disposed between the cutting edge bottom surface 22 and the seat bottom surface 16, and is in contact with the cutting edge bottom surface 22 and the seat bottom surface 16. The brazing material 30 may be further disposed between the cutting edge side surface 24 and the seat wall 17, and may be in contact with the cutting edge side surface 24 and the seat wall 17. The brazing material 30 is filled in at least a part of the recessed structure 28. The brazing material 30 may be filled in the entire recessed structure 28. The flank surface 23 is located outside the base metal 10 with respect to the side surface 13 of the base metal 10.

[0069] The manufacturing method of cutting tool 1 of the present embodiment includes a step (S3) of holding base metal 10 with a holder. For example, a locking member (not shown) of the holder (not shown) is locked into through hole 19 of base metal 10. In this manner, base metal 10 is held by the holder.

[0070] The method for manufacturing cutting tool 1 of this embodiment includes a step (S4) of forming cutting edge 25 by laser processing flank 23 of sintered cutting edge body 20p.

[0071] 8, the laser light source 35 emits a laser beam 36. The laser light source 35 is, for example, a Nd:YAG pulsed laser or a YVO 4 The laser beam 36 is, for example, a pulsed Nd:YAG laser or a YVO 4The laser has a wavelength of the pulsed laser, a wavelength of the second harmonic (SHG) of the laser wavelength, or a wavelength of the third harmonic (THG) of the laser wavelength. The laser beam 36 is focused by a focusing optical system 37 including a lens. The laser beam 36 is irradiated along the flank 23 of the sintered cutting edge body 20p. The laser beam 36 may be incident on the sintered cutting edge body 20p from the side of the bottom surface 22 of the cutting edge, or may be incident on the sintered cutting edge body 20p from the side of the rake face 21. The flank 23 of the sintered cutting edge body 20p is laser machined to form the cutting edge member 20 including the cutting edge 25. In this manner, the cutting tool 1 is obtained.

[0072] The first laser irradiation conditions in the laser processing of step (S4) are, for example, a laser wavelength of 532 nm or more and 1064 nm or less, a laser spot diameter of 5 μm or more and 70 μm or less as half-width, a laser focal depth of 0.5 mm or more and 20 mm or less, a laser output of 1 W or more and 20 W or less at the laser processing point, and a laser scanning speed of 5 mm / sec or more and 100 mm / sec or less.

[0073] A first extension surface 23b of the flank 23 from the cutting edge bottom surface 22 toward the lower surface 12 of the base metal 10 is spaced from the side surface 13 of the base metal 10. The laser beam 36 for forming the cutting edge 25 is irradiated to the flank 23 without being irradiated to the base metal 10. The protruding length t of the flank 23 is 0.01 mm or more. Therefore, it is possible to easily prevent the laser beam 36 for forming the cutting edge 25 from being irradiated to the base metal 10.

[0074] The binder increases the absorption rate of the polycrystalline diamond sintered body with respect to the laser beam 36 when the cutting edge 25 is formed by laser processing. Therefore, the cutting edge 25 can be easily formed by laser processing.

[0075] In step (S4), the flank 23 may be laser-machined to generate at least one of graphite and cobalt oxide on the flank 23. Specifically, in step (S4), the flank 23 is laser-machined to convert a portion of the polycrystalline diamond into graphite. Thus, graphite is generated on the flank 23. In step (S4), the flank 23 is laser-machined to convert a portion of the cobalt contained in the binder into cobalt oxide. Thus, cobalt oxide is generated on the flank 23. When at least one of graphite and cobalt oxide is generated on the flank 23, the cutting edge sintered body 20p differs from the cutting edge member 20 in the amount of at least one of graphite and cobalt oxide on the flank 23.

[0076] 12, another example of the method for manufacturing the cutting tool 1 may further include a step (S5) of irradiating the laser beam 36 along the flank 23 to laser-machine the flank 23 under second laser irradiation conditions different from the first laser irradiation conditions, thereby generating at least one of graphite and cobalt oxide on the flank 23. In the step (S5), the flank 23 is laser-machined to convert a part of the polycrystalline diamond into graphite. Thus, graphite is generated on the flank 23. In the step (S5), the flank 23 is laser-machined to convert a part of the cobalt contained in the binder into cobalt oxide. Thus, cobalt oxide is generated on the flank 23.

[0077] The amount of graphite generated on the flank 23 in step (S5) is greater than the amount of graphite generated on the flank 23 in step (S4). The amount of graphite generated on the flank 23 in step (S4) may be zero. The amount of cobalt oxide generated on the flank 23 in step (S5) is greater than the amount of cobalt oxide generated on the flank 23 in step (S4). The amount of cobalt oxide generated on the flank 23 in step (S4) may be zero.

[0078] 8, in step (S5), the laser light source 35 emits a laser beam 36. The laser light source 35 is, for example, a Nd:YAG pulsed laser or a YVO 4 The laser beam 36 is, for example, a pulsed Nd:YAG laser or a YVO 4 The laser beam 36 has a wavelength of a pulsed laser, a wavelength of a second harmonic (SHG) of the laser wavelength, or a wavelength of a third harmonic (THG) of the laser wavelength. The laser beam 36 is focused by a focusing optical system 37. The laser beam 36 is irradiated along the flank 23. The laser beam 36 may be incident on the flank 23 from the side of the cutting edge bottom surface 22, or may be incident on the flank 23 from the side of the rake face 21.

[0079] The ratio of graphite in the flank 23 subjected to the laser processing in step (S5) is 0.01 or more and 0.50 or less. When the volume average diameter of the polycrystalline diamond is 10 μm or more, the polycrystalline diamond is prevented from being excessively converted to graphite by the laser processing, and the ratio of graphite in the flank 23 can be 0.50 or less. The hardness of the flank 23 is prevented from being excessively reduced, and the wear resistance of the cutting tool 1 can be improved. In contrast, when the volume average diameter of the polycrystalline diamond is less than 10 μm, the polycrystalline diamond is excessively converted to graphite by the laser processing, and the ratio of graphite in the flank 23 exceeds 0.50. The hardness of the flank 23 is excessively reduced, and the wear resistance of the cutting tool is reduced.

[0080] For example, when the volume mean diameter of the polycrystalline diamond was 10 μm or more, the wear width of the flank 23 after 300 machining passes was 65 μm. In contrast, when the volume mean diameter of the polycrystalline diamond was more than 1 μm and less than 10 μm, the wear width of the flank 23 after 300 machining passes was 77 μm. When the volume mean diameter of the polycrystalline diamond was 1 μm or less, the wear width of the flank 23 after 300 machining passes was 83 μm.

[0081] The polycrystalline diamond sintered body contains 25% by weight or more of cobalt oxide at the flank 23 that has been subjected to the laser processing in step (S5). This can improve the wear resistance of the flank 23. Thus, the wear resistance of the cutting tool 1 can be improved.

[0082] The second laser irradiation conditions in step (S5) are different from the first laser irradiation conditions in step (S4). An example of the second laser irradiation conditions in step (S5) is shown below.

[0083] The light intensity distribution of the laser beam 36 in step (S5) is gentler than that of the laser beam 36 in step (S4). The light intensity distribution of the laser beam 36 means the light intensity distribution of the laser beam 36 in a cross section perpendicular to the traveling direction of the laser beam 36. For example, the laser beam 36 in step (S5) is more defocused than the laser beam 36 in step (S4). For example, by changing the focal length of the focusing optical system 37 between steps (S4) and (S5), the light intensity distribution of the laser beam 36 in step (S5) can be made gentler than that of the laser beam 36 in step (S4).

[0084] The second laser irradiation conditions are, for example, a laser wavelength of 532 nm or more and 1064 nm or less, a laser spot diameter of 5 μm or more and 70 μm or less as a half-width, a laser focal depth of 1.0 mm or more, a laser output of 1 W or more and 20 W or less at the laser processing point, and a laser scanning speed of 5 mm / sec or more and 100 mm / sec or less. The second laser irradiation conditions are, for example, preferably a laser wavelength of 532 nm or more and 1064 nm, a laser spot diameter of 10 to 50 μm as a half-width, a laser focal depth of 1.5 mm or more, a laser output of 2 to 10 W, and a laser scanning speed of 30 to 100 mm / min.

[0085] The laser focal depth in the second laser irradiation condition is not particularly limited, but may be 20 mm or less. The laser pulse width is, for example, 1 f (femto) second or more and 1 μsec or less. The laser repetition frequency is, for example, 10 Hz or more and 1 MHz or less.

[0086] An example of a method for remanufacturing the cutting tool 1 of this embodiment will be described with reference to FIGS.

[0087] An example of a method for remanufacturing the cutting tool 1 of the present embodiment includes a step (S11) of holding the cutting tool 1 with a holder. With reference to FIG. 10 , during cutting of a workpiece (not shown), a chip 38 may occur in the cutting edge 25. The cutting tool 1 with the chip 38 occurring in the cutting edge 25 is held by the holder. For example, the base metal 10 of the cutting tool 1 is held by the holder (not shown). Specifically, a locking member (not shown) of the holder (not shown) is locked to the through hole 19 of the base metal 10.

[0088] An example of a method for remanufacturing the cutting tool 1 of this embodiment includes a step (S12) of regenerating the cutting edge 25 by laser processing the flank 23 of the cutting edge member 20. With reference to Fig. 11, a laser beam 36 is irradiated along the flank 23 of the cutting edge member 20. The flank 23 of the cutting edge member 20 is laser processed to remove the chip 38. The laser beam 36 may be incident on the cutting edge member 20 from the side of the bottom surface 22 of the cutting edge, or may be incident on the cutting edge member 20 from the side of the rake face 21. In this manner, the cutting edge 25 is regenerated.

[0089] A first extension surface 23b of the flank 23 from the cutting edge bottom surface 22 toward the lower surface 12 of the base metal 10 is spaced apart from the side surface 13 of the base metal 10. The laser beam 36 for regenerating the cutting edge 25 is irradiated onto the flank 23 without irradiating onto the base metal 10. The protruding length t of the flank 23 is 0.01 mm or more. reproduction Therefore, it is possible to easily prevent the laser beam 36 for performing the laser beam cutting on the base metal 10.

[0090] <Example> The present disclosure will be described in detail below with reference to examples. However, the present disclosure is not limited to the examples.

[0091] The cutting tools of Samples No. 1 to No. 16 prepared as described above were subjected to the following cutting test to evaluate the life of the cutting tools.

[0092] A cutting tool is used to machine a workpiece having a cylindrical shape with a diameter of 100 mm and made of an Al alloy (A390). The cutting conditions are as follows: cutting speed is 3000 mm / min; feed rate is 5730 mm / min; cutting depth (ap) is 0.50 mm; and the maximum number of machining passes is 300. The number of machining passes from the start of cutting the workpiece with the cutting tool until the wear width of the flank of the cutting tool reaches 100 μm is defined as the life of the cutting tool. Note that even if the wear width of the flank of the cutting tool does not reach 100 μm when the number of machining passes is 300, the life of the cutting tool is still defined as 300.

[0093] Cutting tools Samples No. 1 to No. 13 are examples of the present embodiment, while cutting tools Samples No. 14 to No. 16 are comparative examples.

[0094] Specifically, the thickness of the cutting edge member of each of the cutting tools of Sample No. 14 and Sample No. 15 is 1.0 mm, which is the same as the thickness of the cutting edge member of each of the cutting tools of Sample No. 1 and Sample No. 8 to Sample No. 13. However, the cutting edge member of each of the cutting tools of Sample No. 14 and Sample No. 15 is a laminate of a polycrystalline diamond sintered body layer and a backing plate which is a sintered carbide layer. The polycrystalline diamond sintered body layer has a thickness of 0.5 mm, and the backing plate also has a thickness of 0.5 mm. In the cutting tool of Sample No. 14, the cutting edge is formed by grinding the flank of the cutting edge member with a grindstone. The cutting tool of Sample No. 16 has the same configuration as the cutting tool of Sample No. 1, but differs from the cutting tool of Sample No. 1 in that the thickness of the cutting edge member is smaller than that of the cutting tool of Sample No. 1. The results of the cutting test are shown in Table 1.

[0095] [Table 1]

[0096] From the results of the cutting test shown in Table 1, the cutting tools of Samples No. 1 to No. 13 have long lifespans, similar to the cutting tool of Sample No. 14.

[0097] In contrast, the life of the cutting tool of sample No. 15 is shorter than the life of the cutting tools of sample No. 1 to sample No. 13. It was confirmed that the brazing material melts when the cutting edge is formed by laser processing in the cutting tool of sample No. 15. In order to form the cutting edge in the cutting tool of sample No. 15, in addition to the polycrystalline diamond sintered body layer, the backing plate, which is the sintered carbide layer, must also be laser processed. The time required for laser processing increases, and more heat is generated in the cutting edge member. Therefore, it is considered that the brazing material melts when the cutting edge is formed by laser processing in the cutting tool of sample No. 15. As a result, in the cutting tool of sample No. 15, the fixing strength of the cutting edge member to the base metal decreases, and the cutting edge member falls off from the base metal with fewer processing passes. For the above reasons, the life of the cutting tool of sample No. 15 is shorter than the life of the cutting tools of sample No. 1 to sample No. 13.

[0098] The life of the cutting tool of Sample No. 16 is shorter than the life of the cutting tools of Sample No. 1 to Sample No. 13. When cutting a workpiece using the cutting tool, heat is generated at the cutting edge. The thickness of the cutting edge member of the cutting tool of Sample No. 16 is smaller than the thickness of the cutting edge member of each of the cutting tools of Sample No. 1 to Sample No. 13. The distance between the cutting edge and the brazing material of the cutting tool of Sample No. 16 is shorter than the distance between the cutting edge and the brazing material of each of the cutting tools of Sample No. 1 to Sample No. 13. Due to the influence of heat, the brazing material of the cutting tool of Sample No. 16 is more easily melted than the brazing material of each of the cutting tools of Sample No. 1 to Sample No. 13. Therefore, it is considered that the life of the cutting tool of Sample No. 16 is shorter than the life of the cutting tool of Sample No. 1 to Sample No. 13.

[0099] The embodiments disclosed herein are illustrative in all respects and should not be considered as limiting. The scope of the present disclosure is defined by the claims, not the above-described embodiments, and is intended to include the equivalent meaning of the claims and all modifications within the scope. [Explanation of symbols]

[0100] 1 cutting tool, 10 base metal, 11 upper surface, 12 lower surface, 13 side surface, 13b second extension surface, 13c vertical line, 15 seat portion, 16 seat bottom surface, 17 seat wall, 19 through hole, 20 cutting edge material, 20p cutting edge sintered body, 21 scooping surface, 22 cutting edge bottom surface, 23 relief surface, 23b first extension surface, 24 cutting edge side surface, 25 cutting edge, 27 ridge line, 28 concave structure, 30 brazing material, 35 laser light source, 36 laser beam, 37 focusing optical system, 38 chipping.

Claims

1. A base metal on which a seat portion is provided; A cutting edge member which is a polycrystalline diamond sintered body containing polycrystalline diamond and a binder; a brazing material for fixing the cutting edge member to the seat portion of the base metal, the base metal includes an upper surface, a lower surface, and a side surface connected to the upper surface and the lower surface, The seat portion includes a seat bottom surface and a seat wall, The seat bottom surface is recessed from the upper surface toward the lower surface and is connected to the side surface, The seat wall is connected to the top surface, the bottom surface, and the side surface, The cutting edge member includes a rake face extending along the upper surface, a cutting edge bottom surface opposite to the rake face, a flank face connected to the rake face and the cutting edge bottom surface, and a cutting edge formed between the rake face and the flank face, The thickness of the cutting edge member is 0.3 mm or more, The brazing material is disposed between the cutting edge bottom surface and the seat bottom surface and is in contact with the cutting edge bottom surface and the seat bottom surface, The flank surface is located outside the base metal with respect to the side surface of the base metal, The polycrystalline diamond sintered body contains graphite and cobalt oxide on the flank surface, The carbon constituting the polycrystalline diamond is referred to as first carbon, and the carbon constituting the graphite is referred to as second carbon, when a Raman spectroscopy analysis is performed on the flank face, a ratio of the second peak intensity to a sum of a first peak intensity of the first carbon on the flank face and a second peak intensity of the second carbon on the flank face is 0.01 or more and 0.50 or less, The volume mean diameter of the polycrystalline diamond is 10 μm or more; A cutting tool, wherein the polycrystalline diamond sintered body contains 25% by weight or more of the cobalt oxide on the flank surface.

2. The cutting tool according to claim 1 , wherein a ratio of the second peak intensity to a sum of the first peak intensity and the second peak intensity is equal to or greater than 0.10 and equal to or less than 0.

48.

3. The cutting tool according to claim 1 or 2, wherein a first extension surface of the flank from the bottom surface of the cutting edge toward the lower surface of the base metal is spaced apart from the side surface of the base metal.

4. A recessed structure is formed on at least one of the cutting edge bottom surface or the seat bottom surface, The cutting tool according to claim 1 , wherein the brazing material is filled in at least a portion of the recessed structure.

5. The cutting tool according to claim 1 , wherein a protruding length of the flank from the side surface is 0.01 mm or more.

6. The cutting tool according to claim 5 , wherein the protruding length of the flank is 0.50 mm or less.

7. The cutting tool according to claim 1 , wherein the thickness of the cutting edge member is 2.0 mm or less.

8. A cutting tool described in any one of claims 1 to 7, wherein the volume mean diameter of the polycrystalline diamond exceeds 10 μm.

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