Cutting insert, cutting tool, and method for manufacturing cut product

Abstract

A cutting portion of a cutting insert according to one embodiment includes a first surface including a corner, a first side, a first region, a second region, and a third region. The first region is disposed along the corner and the first side. The second region is located further inward than the first region. The third region is located further inward than the second region. The boundary of the corner and the first edge is a first point. A boundary between the first region and the second region in a cross section passing through the first point and orthogonal to the first side is a second point. An imaginary straight line passing through the first point and the second point is a first imaginary straight line. The first imaginary straight line intersects a third region, and a part of the third region is located above the first imaginary straight line.

Description

[0001] This application is a divisional application of an invention patent application with an international application date of July 17, 2019, an international application number of PCT / JP2019 / 028073, a priority date of July 18, 2018, an application number of 201980047598.0, and an invention name of “Cutting insert, cutting tool and method for manufacturing cut product”. Technical Field

[0002] The present invention relates to a cutting insert, a cutting tool and a method for manufacturing a cut product. Background Art

[0003] As a cutting tool used for cutting a workpiece such as a high-hardness material, for example, a cutting tool (cutting insert) described in International Publication No. 2015 / 083716 (Patent Document 1) is used. The cutting insert described in Patent Document 1 has a honed surface and a chip breaker wall surface, and is formed of an ultrahigh pressure sintered body containing cubic boron nitride or diamond.

[0004] For example, when cutting a workpiece made of a high-hardness material such as hardened steel, the handling of chips may become unstable. This is because in hardened steel, the surface hardness is high, while on the other hand, the internal hardness is low. When cutting a workpiece made of a high-hardness material using a cutting blade formed of an ultra-high pressure sintered body as described in Patent Document 1, in order to improve the durability when cutting the hard surface of the hardened steel, the width of the honing surface (land surface) is set to be wider, or the honing angle (land angle) is set to be larger.

[0005] On the other hand, when cutting the lower hardness interior of hardened steel, the chips tend to flow along the honing surface in an unstable state. At this time, in the insert described in Patent Document 1, since the chip breaker wall is low and located away from the cutting edge, it is possible that the chips cannot be processed on the chip breaker wall. Summary of the invention

[0006] A cutting insert in one embodiment has a base portion and a cutting portion. The cutting portion contains a sintered body of cubic boron nitride or diamond and is bonded to the base portion. The cutting portion has a first surface, a second surface and a third surface. The second surface is located on the opposite side of the first surface. The third surface is located between the first surface and the second surface. The first surface has a corner, a first side, a first region, a second region and a third region. The first side extends from the corner. The first region is arranged along the corner and the first side and is inclined upward toward the inner side of the first surface. The second region is arranged along the first region at a position closer to the inner side than the first region and is inclined relative to the first region. The third region is located at a position closer to the inner side than the second region and is inclined upward. The boundary between the corner and the first side is a first point. The boundary between the first region and the second region in a section passing through the first point and orthogonal to the first side when looking down at the first surface is a second point. An imaginary straight line passing through the first point and the second point is a first imaginary straight line. The first imaginary straight line intersects with the third region, and a portion of the third region is located above the first imaginary straight line. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 It is a perspective view of a cutting insert showing one aspect of the present invention which is not limited.

[0008] Figure 2 It is shown Figure 1 An enlarged view of region G1 in FIG.

[0009] Figure 3 yes Figure 1 A top view of the cutting insert is shown.

[0010] Figure 4 It is shown Figure 3 An enlarged view of region G2 in FIG.

[0011] Figure 5 It is shown Figure 4 Cross-sectional view of section VV in FIG.

[0012] Figure 6 It is shown Figure 4 Cross-sectional view of section VI-VI in FIG.

[0013] Figure 7 It is a cross-sectional view of a cutting insert showing one aspect of the present invention which is not limited.

[0014] Figure 8 It is shown Figure 4 A cross-sectional view of section VIII-VIII in FIG.

[0015] Fig. 9 It is a cross-sectional view of a cutting insert showing one aspect of the present invention which is not limited.

[0016] Fig.10 It is shown Figure 4 Cross-sectional view of section XX in .

[0017] Fig.11 It is shown Figure 4 A cross-sectional view of the XI-XI section.

[0018] Fig.12 It is a perspective view of a cutting tool showing a non-limiting aspect of the present invention.

[0019] Fig.13 This is a diagram showing one step in a method for producing a machined product according to one aspect of the present invention which is not limited thereto.

[0020] Fig.14 This is a diagram showing one step in a method for producing a machined product according to one aspect of the present invention which is not limited thereto.

[0021] Fig.15 This is a diagram showing one step in a method for producing a machined product according to one aspect of the present invention which is not limited thereto.

[0022] Description of reference numerals:

[0023] 1 Cutting blade (blade)

[0024] 1a Base

[0025] 1b Cutting part

[0026] 3 Corner

[0027] 5 First side

[0028] 7 First side (upper surface)

[0029] 9 Second side (lower surface)

[0030] 11 The third side (side)

[0031] 13. Area 1

[0032] 15 Second Area

[0033] 17 Third Area

[0034] 19 First Part

[0035] 21 Second Part

[0036] 23 First inclined surface

[0037] 25 Second inclined surface

[0038] 27 Upper end surface

[0039] 29 Lower end surface

[0040] 31 holes

[0041] 101 Cutting Tools

[0042] 103 Slot

[0043] 105 Handle

[0044] 107 Clamping member

[0045] 201 Cutting workpiece

[0046] P1 Center axis

[0047] P2 Center Axis

[0048] θ1 First angle

[0049] θ2 Second angle

[0050] L1 First imaginary straight line

[0051] L2 Second imaginary straight line

[0052] L3 The third imaginary straight line

[0053] M Bisector

[0054] S plane

[0055] S1 Imaginary plane

[0056] S2 imaginary plane. DETAILED DESCRIPTION

[0057] <Cutting inserts>

[0058] Hereinafter, the cutting insert 1 (hereinafter, also referred to as insert 1) of the unrestricted embodiment of the present invention will be described in detail using the accompanying drawings. However, in each figure referred to below, for the convenience of description, only the main components required for the insert 1 of the embodiment are briefly shown. Therefore, the insert 1 of the present invention can be equipped with any constituent components not shown in each figure referred to. In addition, the size of the components in each figure does not truthfully represent the size of the actual structural component and the size ratio of each component.

[0059] like Figure 1 As shown in the example, the blade 1 may include a base portion 1a and a cutting portion 1b. The cutting portion 1b may be a sintered body joined to the base portion 1a and containing at least one of cubic boron nitride (cBN) and diamond. In other words, the cutting portion 1b may contain a sintered body of cubic boron nitride or diamond.

[0060] The blade 1 as a whole may be in the shape of a polygonal plate. Figure 1The blade 1 in the example shown is in a generally quadrilateral plate shape. The base portion 1a may be in a generally polygonal plate shape, and a portion of the corner of the base portion 1a may be cut. Figure 1 As shown in the example, the base portion 1a may be in a substantially quadrilateral plate shape, and a portion of a corner of the base portion 1a may be cut. The cut portion 1b may be joined to the cut portion using solder or the like. Figure 1 As in the example shown, the cutting portion 1b may be substantially in the shape of a triangular plate.

[0061] The base portion 1a and the cutting portion 1b are not limited to the above-mentioned structure. For example, the base portion 1a and the cutting portion 1b may be respectively in the shape of a quadrilateral plate and have the same shape when viewed from above. The cutting portion 1b in the shape of a quadrilateral plate may be located on the base portion 1a in the shape of a quadrilateral plate. The cutting portion 1b may have a first surface 7, a second surface 9, and a third surface 11. The second surface 9 may be located on the opposite side of the first surface 7. The third surface 11 may be located between the first surface 7 and the second surface 9. Figure 2 As shown in the example, the first surface 7 may include a first corner 3 and a first side 5 extending from the first corner 3. Figure 2 As in the example shown, a part of the second surface 9 and the third surface 11 of the cut portion 1b may be joined to the base portion 1a. It should be noted that the above-mentioned plan view may refer to viewing the first surface 7 from the front.

[0062] exist Figure 2 In the example shown, the first surface 7 is located above the cutting portion 1b. Therefore, for convenience, the first surface 7 may also be referred to as the upper surface 7. Figure 2 In the example shown, the second surface 9 is located below the cutting portion 1b. Therefore, for convenience, the second surface 9 may also be referred to as the lower surface 9. Figure 2 As shown in the example, the third surface 11 may be located between the upper surface 7 and the lower surface 9 and connected to these surfaces. Therefore, for convenience, the third surface 11 may also be referred to as a side surface 11.

[0063] The upper surface 7 is polygonal. The upper surface 7 may also be Figure 4 As shown in the example, it is a triangle. Figure 4 As shown in the example, the upper surface 7 may have three corners and three sides. In addition, when the upper surface 7 is a triangle, the side surface 11 may be composed of three surface areas. It should be noted that the shape of the upper surface 7 is not limited to Figure 4 For example, the upper surface 7 may be a quadrilateral, pentagon, hexagon or octagon instead of a triangle, and there is no problem.

[0064] exist Figure 4In the figure, the first corner 3 is one of the three corners of the upper surface 7. In addition, the first side 5 is one of the three sides of the upper surface 7.

[0065] The upper surface 7 only needs to be roughly polygonal, and need not be strictly polygonal. That is, the sides of the polygonal upper surface 7 do not strictly need to be straight lines, and may be, for example, convex curves or concave curves. In addition, the corners of the polygonal upper surface 7 are not limited to the structure obtained by the intersection of two straight lines, and may be, for example, rounded toward the outside.

[0066] like Figure 4 As shown in the example, when looking down at the upper surface 7, the first side 5 can be in a straight line shape. In addition, the first corner 3 can be in a convex curve shape. In this case, the first corner 3 can be in an arc shape with a constant curvature radius, and can also be composed of multiple parts with different curvature radii. It should be noted that in the following description, the top view of the upper surface 7 can also be called the top view.

[0067] The size of the cut portion 1b is not particularly limited, and for example, the length of the first side 5 of the upper surface 7 can be set to about 0.2 to 2 mm. In addition, the height from the upper surface 7 to the lower surface 9 can be set to about 2 to 8 mm.

[0068] The blade 1 may have a cutting edge located at the ridgeline where the upper surface 7 and the side surface 11 intersect. The cutting edge may be used to cut a workpiece. The cutting edge may be located at the entire ridgeline or only at a portion of the ridgeline. For example, the cutting edge may be located at the first corner 3 of the upper surface 7 and at a portion of the first side 5 continuous with the first corner 3. Figure 2 and Figure 4 As in the example shown, the cutting edge may be located in the entire first corner 3 and a portion of the first side 5 adjacent to the first corner 3 .

[0069] like Figure 2 and Figure 4 As shown in the figures, the upper surface 7 may have a first region 13, a second region 15, and a third region 17. The first region 13 may be arranged along the first corner 3 and the first side 5, or may be inclined upward toward the inner side of the upper surface 7. The first region 13 may be a plane or a curved surface. When the first region 13 is a plane, the first region 13 may also be referred to as a chamfer. In addition, when the first region 13 is a curved surface, the first region 13 may also be referred to as a honing surface.

[0070] The second region 15 may be arranged along the first region 13 at a position inside the first region 13, or may be inclined relative to the first region 13. In addition, the third region 17 may be located inside the second region 15, or may be inclined upward. Here, "inclined upward" may mean that it is inclined in a manner away from the lower surface 9 (second surface 9) as it moves toward the inner side of the upper surface 7 (first surface 7).

[0071] The second region 15 may be inclined relative to the first region 13 as described above. In this case, the second region 15 may approach the lower surface 9 as it approaches the inner side of the upper surface 7, or may be parallel to the lower surface 9. In addition, the second region 15 may be away from the lower surface 9 as it approaches the inner side of the upper surface 7. When the second region 15 is away from the lower surface 9 as described above, the inclination of the second region 15 is gentler than that of the first region 13 and the third region 17.

[0072] like Figure 2 As shown, the boundary of the first corner 3 and the first side 5 is the first point A. Figure 5 1 shows a cross section passing through the first point A and being orthogonal to the first side 5 in a top view. Figure 5 As shown in FIG. 1 , the boundary between the first region 13 and the second region 15 is the second point B. In the case of a top view, the boundary between the first region 13 and the second region 15 is represented by a line, but in the case of Figure 5 In the case of the cross-sectional view shown, the above-mentioned boundary is represented by a point. In addition, the virtual straight line passing through the first point A and the second point B is the first virtual straight line L1.

[0073] Here, an imaginary straight line passing through the center (center of gravity) of the upper surface 7 and the center (center of gravity) of the lower surface 9 is set as the central axis P1. In addition, an imaginary plane orthogonal to the central axis P1 is set as a reference plane S. Figure 5 In the embodiment, there is also a section passing through the first point A and being orthogonal to the first side 5 when looking down at the reference plane S. Figure 5 In the example shown, the lower surface 9 is parallel to the reference plane S. Therefore, “inclined upward” can also be said to be inclined so as to be away from the reference plane S as going toward the inner side of the upper surface 7 (first surface 7 ).

[0074] like Figure 5 As shown in the example, the first imaginary straight line L1 may intersect the third region 17. In this case, the chip discharge performance of the insert 1 is high. For example, even when cutting hardened steel, which is a kind of high hardness material, the chip discharge performance is high.

[0075] The hardness of hardened steel is high on the surface and low inside. When the upper surface 7 has the first region 13 inclined upward, the cutting edge is less likely to break when cutting the relatively hard surface of hardened steel and has high durability.

[0076] In addition, Figure 5 In the example shown, the upper surface 7 has an upwardly inclined third region 17, which intersects with the first imaginary straight line L1 as described above. Therefore, when cutting the relatively low hardness of the inner part of the hardened steel, even if the chips move in the direction along the first region 13, the chips are easily bent in the third region 17.

[0077] Moreover, in Figure 5 In the example shown, when the upper surface 7 has the second region 15 located between the first region 13 and the third region 17, the bending of the chips is easily promoted. This is because, when the upper surface 7 has the second region 15 with a gentler inclination than the first region 13 and the third region 17, it is easy to ensure a space for the chips to bend on the second region 15.

[0078] Thus, even if we assume Figure 5 The blade 1 in the example shown has high chip discharge performance even when cutting a member having a high hardness material such as hardened steel and uneven hardness. Figure 5 The insert 1 in the example shown is less affected by processing conditions such as the material of the workpiece and has high versatility for the workpiece.

[0079] In addition, if Figure 6 As shown in the example, the third area 17 can be away from the second imaginary straight line L2. Here, the boundary between the side surface 11 and the first area 13 at the position of the bisector M of the first corner 3 when looking down at the upper surface 7 is the third point C. In addition, at the position of the bisector M of the first corner 3 when looking down at the upper surface 7, the boundary between the second area 15 and the first area 13 is the fourth point D. And the imaginary straight line passing through the third point C and the fourth point D is the second imaginary straight line L2.

[0080] When the insert 1 has the above structure, since the third region 17 is not too close to the cutting edge, the chips are not excessively bent and are easily formed into a good chip shape. Therefore, the chips are stably discharged and chip clogging is unlikely to occur.

[0081] It should be noted that when the first corner 3 is a convex curve shape, an imaginary straight line passing through the center of the first corner 3 and being orthogonal to the first corner 3 at the center of the first corner 3 when looking down at the upper surface 7 can be regarded as the bisector M of the first corner 3.

[0082] In addition, if Figure 7As shown in the example, the third area 17 may intersect with the second imaginary straight line L2. When the insert 1 has the above structure, the chip is easy to contact the third area 17 not only at the position of the orthogonal line of the first side 5 when viewed from the top, but also at the position of the bisector M of the first corner 3 when viewed from the top. Therefore, the behavior of the chip is easy to be stable. Figure 7 is a diagram showing another aspect of the present invention which is not limited thereto, and corresponds to Figure 6 sectional view of .

[0083] In addition, if Figure 8 As shown in the example, the third area 17 may be separated from the third imaginary straight line L3. Here, a point of the first side 5 located farther from the first corner 3 than the first point A is referred to as a fifth point E. The first side 5 may have a fifth point E. Figure 8 4 shows a cross section passing through the fifth point E and being orthogonal to the first side 5 in a top view. Figure 8 As shown, the boundary between the first area 13 and the second area 15 is the sixth point F. Figure 5 Similarly, in Figure 8 In the case of the cross-sectional view shown, the boundary between the first region 13 and the second region 15 is indicated by a dot. In addition, the virtual straight line passing through the fifth point E and the sixth point F is the third virtual straight line L3.

[0084] When the insert 1 has the above structure, since the third region 17 is not too close to the cutting edge, the chips are not excessively bent and are easily formed into a good chip shape. Therefore, the chips are stably discharged and chip clogging is unlikely to occur.

[0085] In addition, if Figure 4 As shown in the example, the third region 17 may have a first inclined surface 23 and a second inclined surface 25. The second inclined surface 25 may be located closer to the second region 15 than the first inclined surface 23. Specifically, the second inclined surface 25 may be located between the first inclined surface 23 and the second region 15.

[0086] Here, if Figures 5 to 9 As shown, the inclination angle of the first inclined surface 23 relative to the reference plane S parallel to the lower surface 5 is a first angle θ1. In addition, the inclination angle of the second inclined surface 25 relative to the reference plane S is a second angle θ2. In this case, the first angle θ1 may be greater than the second angle θ2. Specifically, Figures 5 to 9 As shown, in a cross section that includes a line orthogonal to the first side 5 and is orthogonal to the reference plane, the third region 17 may have a portion where the first angle θ1 is larger than the second angle θ2.

[0087] It should be noted that in Figures 5 to 9In order to facilitate visual understanding, an imaginary plane S1 parallel to the reference plane S and intersecting the first inclined surface is shown, and the first angle θ1 is shown by the inclination angle of the first inclined surface 23 relative to the imaginary plane S1. In addition, an imaginary plane S2 parallel to the reference plane S and intersecting the second inclined surface 25 is shown, and the second angle θ2 is shown by the inclination angle of the second inclined surface 25 relative to the imaginary plane S2. Fig. 9 is a diagram showing another aspect of the present invention which is not limited thereto, and corresponds to Figure 8 sectional view of .

[0088] When the second inclined surface 25 is located closer to the second region 15 than the first inclined surface 23, the second inclined surface 25 is located closer to the cutting edge than the first inclined surface 23. When the second angle θ2 of the second inclined surface 25 located closer to the cutting edge than the first inclined surface 23 is smaller than the first angle θ1, when the chips generated by the cutting edge move toward the third region 17, the chips are difficult to bend sharply, but are easy to bend gradually. That is, at the position close to the cutting edge, the chips are difficult to bend excessively and are easy to form a good chip shape. Therefore, chip clogging is difficult to occur.

[0089] When the first angle θ1 of the first inclined surface 23 located farther from the cutting edge than the second inclined surface 25 is larger than the second angle θ2, the distance between the first inclined surface 23 and the cutting edge is small. Therefore, the chips easily come into contact with the first inclined surface 23, and thus the behavior of the chips tends to be stable.

[0090] As described above, when the first angle θ1 is larger than the second angle θ2, the chip discharge performance of the insert 1 is higher.

[0091] In addition, if Figure 4 As shown in the example, the first side 5 may include a first portion 19 and a second portion 21. The first portion 19 may be connected to the first corner 3. The second portion 21 may be located farther from the first corner 3 than the first portion 19.

[0092] The orthogonal line of the first portion 19 in the top view is the first orthogonal line. The orthogonal line of the second portion 21 in the top view is the second orthogonal line. In addition, the distance from the first portion 19 to the upper end of the third region 17 on the first orthogonal line is the first distance. The distance from the second portion 21 to the upper end of the third region 17 on the second orthogonal line is the second distance. Here, the upper end of the third region 17 refers to the portion of the third region 17 that is farthest from the lower surface 9 within the range of the object.

[0093] The second distance d2 may be greater than the first distance d1. Fig.10In the example shown, a first distance d1 is shown in a cross section that includes a first orthogonal line and is orthogonal to the reference plane S. Fig.11 In the example shown, the second distance d2 in the cross section that includes the second orthogonal line and is orthogonal to the reference plane S is shown.

[0094] When the insert 1 has the above-described structure, it is easy to ensure a space for chip discharge when the chips advance from the center of the first corner 3 in the direction along the first side 5. Therefore, the chip discharge performance of the insert 1 is further improved.

[0095] In addition, if Figure 1 As shown in the example, the blade 1 may have a hole 31 opened at the upper end surface 27. The hole 31 may penetrate to the lower end surface 29. In addition, the hole 31 is not limited to the above-mentioned method, for example, it may also open on the side of the blade 1. In addition, the hole 31 may penetrate from one of the multiple surface areas constituting the side of the blade 1 to another surface area located on the opposite side of the surface area. It should be noted that in Figure 1 In FIG. 1 , the center axis P2 of the hole 31 is indicated by a double-dotted line. Figure 1 As in the example shown, the central axis P2 of the hole 31 may be parallel to the central axis P1 of the cutting portion 1 b.

[0096] The hole 31 can be used as an insertion hole for a fixing member when the blade 1 is mounted on the handle. Examples of the fixing member include screws, clamping members, and wedges.

[0097] As the material of the cutting portion 1b, cubic boron nitride (cBN) and diamond can be cited. As diamond, for example, PCD (polycrystalline diamond) can be cited. The cutting portion 1b can contain only one of these materials, or two of them. In addition, as long as the cutting portion 1b contains these materials as the main components, it can also contain materials other than these materials. It should be noted that the main component here refers to the component with the largest content ratio calculated by mass ratio.

[0098] Examples of the material of the base body 1 a include cemented carbide, cermet, and ceramic, but the base body 1 a is not limited to these materials.

[0099] In addition, the blade 1 may also have a structure other than the base 1a and the cutting portion 1b. For example, the blade 1 may also have a coating coating the surface of the base 1a and the cutting portion 1b. The coating may cover the entire surface of the base composed of the base 1a and the cutting portion 1b, or may only cover a portion of the surface of the base.

[0100] Examples of the material of the coating layer include aluminum oxide (aluminum oxide), and titanium carbides, nitrides, oxides, oxycarbides, oxynitrides, carbonitrides, and oxycarbonitrides. The coating layer may contain only one of the above materials, or may contain a plurality of them.

[0101] In addition, the coating can be a structure of only one layer or a structure of multiple layers. It should be noted that the material of the coating is not limited thereto. For example, the coating can be located on the substrate by using a chemical vapor deposition (CVD) method or a physical vapor deposition (PVD) method.

[0102] <Cutting Tools>

[0103] Next, the cutting tool 101 according to the embodiment will be described using the drawings.

[0104] like Fig.12 As shown, the cutting tool 101 of the embodiment may also have a shank 105 extending from the first end 105a toward the second end 105b. The shank 105 may have a groove 103 (blade groove) on the first end 105a side. The cutting tool 101 may include the above-mentioned blade 1 located in the groove 103. At least a part of the first corner and the first side that serve as a cutting edge may protrude from the first end 105a of the shank 105.

[0105] The knife handle 105 may be in the shape of a long and thin rod. A knife groove 103 may also be provided on the first end 105a side of the knife handle 105. The knife groove 103 is a portion for assembling the blade 1, and may be open relative to the end surface of the first end 105a side of the knife handle 105. When the knife groove 103 is also open relative to the side surface of the knife handle 105, the blade 1 can be easily assembled. Fig.12 The knife groove 103 in the example shown may have a seating surface and a limiting side surface. The seating surface may be a surface substantially parallel to the lower surface of the knife handle 105. The limiting side surface may be a surface inclined relative to the seating surface.

[0106] The blade 1 may be located in the knife groove 103. At this time, the lower end surface of the blade 1 may be directly in contact with the knife groove 103, and a sheet may be sandwiched between the blade 1 and the knife groove 103.

[0107] like Fig.12 As shown in the example, the blade 1 can be mounted on the handle 105 by a clamping member 107. The blade 1 can be restrained in the blade groove 103 by pressing the head of the clamping member 107 against the inner wall of the hole of the blade 1.

[0108] Steel, cast iron, etc. can be used as the shank 105. In particular, when steel is used for these members, the toughness of the shank 105 is high.

[0109] In the embodiment, a cutting tool for so-called turning is illustrated. As turning, for example, inner diameter processing, outer diameter processing, end surface processing and slotting processing can be listed. It should be noted that the cutting tool is not limited to turning. For example, the blade 1 of the above embodiment can also be used for a cutting tool used in milling.

[0110] <Method for manufacturing machined product>

[0111] Next, a method for producing a machined product according to an embodiment will be described using the drawings.

[0112] The machined product is manufactured by machining the workpiece 201. The method for manufacturing the machined product of the embodiment includes the following steps.

[0113] (1) A step of rotating the workpiece 201;

[0114] (2) a step of bringing at least a portion of the first corner and the first side of the cutting tool 101 represented by the above-described embodiment, which portion serves as a cutting edge, into contact with the rotating workpiece 201; and

[0115] (3) A step of separating the cutting tool 101 from the workpiece 201 .

[0116] More specifically, first, Fig.13 As shown in FIG. 1 , the workpiece 201 is rotated about the axis O1, and the cutting tool 101 is relatively close to the workpiece 201. Next, as shown in FIG. Fig.14 As shown in FIG. 1 , at least a portion of the first corner and the first side of the cutting tool 101 that serve as the cutting edge is brought into contact with the workpiece 201, thereby cutting the workpiece 201. Then, as shown in FIG. Fig.15 As shown, the cutting tool 101 is relatively far away from the workpiece 201 .

[0117] The cutting tool 101 may be moved in the Y1 direction while the axis O1 is fixed and the workpiece 201 is rotated, thereby bringing the cutting tool 101 close to the workpiece 201. The workpiece 201 may be cut by bringing at least a portion of the first corner and the first side of the blade 1 that serve as a cutting edge into contact with the rotating workpiece 201 and moving the at least a portion in the X1 direction. In addition, the cutting tool 101 may be moved away from the workpiece 201 by moving the cutting tool 101 in the Y2 direction while the workpiece 201 is rotated.

[0118] It should be noted that in the cutting process in the manufacturing method of the embodiment, the cutting tool 101 is moved in each step to make the cutting tool 101 contact with the workpiece 201 or to move away from the workpiece 201, but it is of course not limited to this mode.

[0119] For example, in the step (1), the workpiece 201 may be brought close to the cutting tool 101. Similarly, in the step (3), the workpiece 201 may be moved away from the cutting tool 101. When the cutting process is continued, the step of repeatedly making the workpiece 201 rotate while at least a portion of the first corner and the first side of the insert 1 that serve as the cutting edge contact different portions of the workpiece 201 may be repeated.

[0120] It should be noted that typical examples of the material of the workpiece 201 include hardened steel, carbon steel, alloy steel, stainless steel, cast iron, and non-ferrous metals.

Claims

1. A cutting insert, wherein: The cutting insert comprises: a base portion; and a cutting portion comprising a sintered body of cubic boron nitride or diamond and joined to the base portion, The cutting part comprises: First side; a second surface located on an opposite side of the first surface; and a third surface, which is located between the first surface and the second surface, The first surface has: corner; a first side extending from the corner; a first area disposed along the corner and the first side and inclined upward toward the inner side of the first surface; a second region disposed along the first region at an inner side than the first region and inclined relative to the first region; as well as The third area is located inside the second area and is inclined upward. The corner and the boundary of the first side are the first point, The boundary between the first region and the second region in a cross section passing through the first point and orthogonal to the first side when the first surface is viewed from above is a second point, An imaginary straight line passing through the first point and the second point is a first imaginary straight line, The first imaginary straight line intersects the third region, and a portion of the third region is located above the first imaginary straight line.

2. The cutting insert according to claim 1, wherein At the position of the bisector of the corner when looking down at the first surface, the boundary between the third surface and the first area is a third point and the boundary between the second area and the first area is a fourth point, The imaginary straight line passing through the third point and the fourth point is the second imaginary straight line, The third area is far away from the second imaginary straight line.

3. The cutting insert according to claim 1 or 2, wherein: The first side has a fifth point located further away from the corner than the first point, The boundary between the second region and the first region in a cross section passing through the fifth point and orthogonal to the first side when the first surface is viewed from above is a sixth point, The imaginary straight line passing through the fifth point and the sixth point is the third imaginary straight line. The third area is far away from the third imaginary straight line.

4. The cutting insert according to any one of claims 1 to 3, wherein The third area has: a first inclined surface; as well as a second inclined surface located closer to the second region than the first inclined surface, An imaginary plane parallel to the second surface is a reference plane. In a cross section passing through the first point and being orthogonal to the first side when looking down at the first surface, A first angle, which is an inclination angle of the first inclined surface with respect to the reference surface, is larger than a second angle, which is an inclination angle of the second inclined surface with respect to the reference surface.

5. The cutting insert according to any one of claims 1 to 4, wherein The third area has: a first inclined surface; as well as a second inclined surface located closer to the second region than the first inclined surface, The first side has: A first portion connected to the corner; and a second portion located further away from the corner than the first portion, When looking down at the first surface, The orthogonal line of the first part is a first orthogonal line, and the orthogonal line of the second part is a second orthogonal line, A distance on the first orthogonal line from the first portion to a portion of the third region farthest from the second surface is a first distance, The distance on the second orthogonal line from the second portion to the portion of the third region farthest from the second surface is a second distance. The second distance is greater than the first distance.

6. A cutting tool, wherein: The cutting tool has: a knife handle extending from a first end toward a second end and having a knife groove located at a side of the first end; and The cutting insert according to any one of claims 1 to 5, which is located in the cutting groove.

7. A method for manufacturing a machined product, wherein: The method for manufacturing a machined product comprises the following steps: Rotate the workpiece being cut; Bringing the cutting tool according to claim 6 into contact with the rotating workpiece; as well as The cutting tool is separated from the workpiece.

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