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

Abstract

The present invention addresses the problem of achieving both the strength of a cutting edge due to a land surface and the sharpness of a flat cutting edge. A cutting insert (1) has a first side (15) connected to a first corner (11), and a land surface (19) positioned along a cutting blade (9). The cutting blade (9) has a first cutting blade (23) positioned on the first side (15). The land surface (19) has a first land surface (31) positioned along the first cutting blade (23). The first land surface (31) has a first region (31a), and a second region (31b) positioned further away from the first corner (11) than the first region (31a). The width (W1) in a direction orthogonal to the first side (15) in the first region (31a) decreases with increasing distance from the first corner (11), and the width (W2) in a direction orthogonal to the first side (15) in the second region (31b) increases with increasing distance from the first corner (11).

Description

Cutting insert, cutting tool, and method for manufacturing machined product CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to Japanese Patent Application No. 2024-062200, filed on April 8, 2024, the entire disclosure of which is incorporated herein by reference.

[0002] The present disclosure relates to methods of manufacturing cutting inserts, cutting tools, and machined workpieces.

[0003] Known cutting inserts are disclosed in, for example, JP-A No. 2000-514365 (Patent Document 1) and JP-A No. 2011-110635 (Patent Document 2) as cutting tools used in cutting workpieces such as metals. The cutting insert disclosed in Patent Document 2 has a flat land provided along the cutting edge.

[0004] In the cutting insert described in Patent Document 2, the flat land located along the cutting edge is used as a support surface during sintering. Therefore, it is necessary to increase the width of the entire flat land. Furthermore, the width of the flat land is made constant so that the cutting insert is stably supported. However, as the width of the flat land increases, the sharpness of the cutting edge decreases. Therefore, it has been difficult to achieve both the strength of the flat land and the sharpness of the cutting edge.

[0005] A non-limiting one-sided cutting insert of the present disclosure includes a first surface, a second surface located opposite the first surface, a third surface connected to the first surface and the second surface, and a cutting edge located at an intersection of the first surface and the third surface. The first surface has a first corner, a first side connected to the first corner, and a land surface located along the cutting edge. The cutting edge has a first cutting edge located on the first side, and the land surface has a first land surface located along the first cutting edge. The first land surface has a first region and a second region located farther from the first corner than the first region. The width of the first region in a direction perpendicular to the first side decreases with increasing distance from the first corner. The width of the second region in a direction perpendicular to the first side increases with increasing distance from the first corner.

[0006] 15 is a perspective view showing an unlimited one-sided cutting insert of the present disclosure. 15 is a top view of the cutting insert shown in FIG. 1 as seen from the A1 direction. 15 is an enlarged view of region B1 shown in FIG. 2. 15 is the same enlarged view as FIG. 3. 15 is the same enlarged view as FIG. 3. 15 is a bottom view of the cutting insert shown in FIG. 1 as seen from the A2 direction. 15 is a side view of the cutting insert shown in FIG. 2 as seen from the A3 direction. 15 is a side view of the cutting insert shown in FIG. 2 as seen from the A4 direction. 15 is a cross-sectional view taken along line IX-IX of FIG. 15. 15 is a cross-sectional view taken along line X-X ... XI-XI of FIG. 15. 15 is a cross-sectional view taken along line XII-XII of FIG. 15. 15 is a cross-sectional view taken along line XIII-XIII of FIG. 15. 15 is a cross-sectional view taken along line XIV-XIV of FIG. 15. 15 is a perspective view showing an unlimited one-sided cutting tool of the present disclosure. 15 is an enlarged view of region B2 of FIG. 15. Fig. 16 is a side view of the cutting tool shown in Fig. 15. Fig. 17 is a schematic view showing one step in a method for manufacturing a machined product with one surface, which is not limited to the present disclosure. Fig. 18 is a schematic view showing one step in a method for manufacturing a machined product with one surface, which is not limited to the present disclosure. Fig. 19 is a schematic view showing one step in a method for manufacturing a machined product with one surface, which is not limited to the present disclosure.

[0007] <Cutting Insert> Hereinafter, a non-limiting one-sided cutting insert 1 of the present disclosure will be described in detail with reference to the drawings (hereinafter, also simply referred to as the insert 1). However, for the sake of convenience, the drawings referred to below show only the main components necessary for explaining the insert 1 of the embodiment in a simplified form. Therefore, the insert 1 of the present disclosure may include any components not shown in the drawings referred to. Furthermore, the dimensions of the components in the drawings do not faithfully represent the dimensions of the actual components and the dimensional ratios of each component. Note that the present disclosure is not limited to the following aspects.

[0008] 1, 7 and 8, the insert 1 may have a first surface 3, a second surface 5 and a third surface 7. The second surface 5 may be located opposite the first surface 3. The third surface 7 may be located between the first surface 3 and the second surface 5. The third surface 7 may be connected to the first surface 3 and the second surface 5.

[0009] In a non-limiting example shown in Fig. 1 , the first surface 3 is located at the upper end of the insert 1. Therefore, the first surface 3 may be conveniently referred to as the upper surface 3. In a non-limiting example shown in Fig. 1 , the second surface 5 is located at the lower end of the insert 1. Therefore, the second surface 5 may be conveniently referred to as the lower surface 5. In a non-limiting example shown in Fig. 1 , the third surface 7 is located between the upper surface 3 and the lower surface 5 and is connected to these surfaces. Therefore, the third surface 7 may be conveniently referred to as the side surface 7.

[0010] The upper surface 3 and the lower surface 5 may each have a polygonal shape, for example, an octagonal shape. In other words, the insert 1 may have a polygonal plate shape, for example, an octagonal plate shape. The upper surface 3 and the lower surface 5 may each have a triangular, square, pentagonal, or hexagonal shape instead of an octagonal shape. In other words, the insert 1 may have a triangular, square, pentagonal, or hexagonal shape instead of an octagonal plate shape. The polygonal shape is not limited to a polygonal shape in the strict sense.

[0011] 1 , the insert 1 may include a cutting edge 9 located at the intersection of the top surface 3 and the side surface 7. The cutting edge 9 may be used to cut a workpiece. The cutting edge 9 may be located at the entire intersection, or may be located only at a portion of the intersection.

[0012] 1 and 2 , the upper surface 3 may have a first corner 11, a first side 15, a land surface 19, and a rake face 20. The first side 15 may be connected to the first corner 11. The first side 15 does not have to be a straight line in the strict sense, and may be, for example, a slightly curved convex or concave curve. Note that "slightly curved" means that the radius of curvature of the curved first side 15 is sufficiently large compared to the length of the first side 15, specifically, the radius of curvature of the first side 15 is 10 times or more the length of the first side 15.

[0013] 3 to 5 , the first point P1 may be a point where the radius of curvature changes between the first corner 11 and the first side 15. The first point P1 may be the boundary between the first corner 11 and the first side 15.

[0014] As a non-limiting example shown in Fig. 1 , the land surface 19 may be located along the cutting edge 9. The land surface 19 may be a narrow band-shaped surface region located on the peripheral portion of the upper surface 3 and connected to the side surface 7. The land surface 19 may be used to increase the strength of the cutting edge 9 located on the ridge line where the upper surface 3 and the side surface 7 intersect. Therefore, the land surface 19 may be located along the portion of the ridge line that is used as the cutting edge 9.

[0015] As a non-limiting example shown in Figures 1 and 2, the rake face 20 may be located along the land surface 19. The rake face 20 may be inclined so as to approach the lower surface 5 as it moves inward from the upper surface 3. The rake face 20 may be adjacent to the cutting edge 9 with the land surface 19 sandwiched therebetween. Note that "adjacent" here means that two portions are located close to each other and is not necessarily limited to a configuration in which they are in contact. When the upper surface 3 has the rake face 20, the side surface 7 may have a flank surface.

[0016] The insert 1 may further have a through hole 21. The through hole 21 can be used to insert a fixing member when fixing the insert 1 to the holder. An example of the fixing member is a screw. When fixing the insert 1 to the holder, a clamp member, for example, may be used instead of a screw. As a non-limiting example shown in FIGS. 2 and 6 , the through hole 21 may be formed from the center of the upper surface 3 toward the center of the lower surface 5, but is not limited to such a configuration. For example, the through holes 21 may open in opposing regions of the side surface 7.

[0017] As a non-limiting example shown in Figure 3, the cutting edge 9 may have a first cutting edge 23. The first cutting edge 23 may be located on the first side 15. The first cutting edge 23 may be used as a so-called flat cutting edge.

[0018] 3, the land surface 19 may include a first land surface 31. The first land surface 31 may be located along the first cutting edge 23.

[0019] As a non-limiting example shown in Fig. 3, the first land surface 31 may have a first region 31a and a second region 31b. The second region 31b may be located farther from the first corner 11 than the first region 31a. As a non-limiting example shown in Fig. 3, the second region 31b may be connected to the first region 31a, or may be separated from the first region 31a. When the first region 31a and the second region 31b are separated from each other, another region connected to the first region 31a and the second region 31b may be present between the first region 31a and the second region 31b.

[0020] As a non-limiting example shown in Figure 4, the width in the direction perpendicular to the first side 15 in the first region 31a may be defined as a first width W1, and the width in the direction perpendicular to the first side 15 in the second region 31b may be defined as a second width W2.

[0021] The first width W1 may decrease with increasing distance from the first corner 11. For example, the first width W1 may vary from approximately 2 mm to approximately 0.02 mm.

[0022] The second width W2 may increase with increasing distance from the first corner 11. For example, the second width W2 may vary from approximately 0.02 mm to approximately 2 mm.

[0023] When the insert 1 has the above-described configuration, it is easy to achieve both strength and sharpness of the first cutting edge 23. Therefore, the cutting edge 9 is less likely to be chipped during cutting, and a good machined surface is more likely to be obtained.

[0024] 3, the cutting edge 9 may have a first corner cutting edge 27. The first corner cutting edge 27 may be located at the first corner 11.

[0025] 3 and 4, the land surface 19 may have a second land surface 33. The second land surface 33 may be located along the first corner cutting edge 27. The width of the second land surface 33 in the direction perpendicular to the first corner 11 may be constant or may vary across the second land surface 33. The width of the second land surface 33 may be approximately 1.5 to 2 mm.

[0026] 3 to 5, the first line L1 may be a virtual straight line extending from the first point P1 in a direction perpendicular to the first side 15. The first line L1 may be a boundary between the first land surface 31 and the second land surface 33.

[0027] A virtual line passing through the center of the upper surface 3 and the center of the lower surface 5 may be the reference axis. As in a non-limiting example shown in FIGS. 9 to 14 , a virtual plane including the cutting edge 9 and perpendicular to the reference axis may be the surface S. The angle formed by the land surface 19 and the surface S may be the inclination angle of the land surface 19. In other words, the angle at which the land surface 19 is inclined with respect to the lower surface 5 may be the inclination angle of the land surface 19. Specifically, in a non-limiting example shown in FIGS. 9 and 10 , the angle formed by the first land surface 31 and the surface S may be the first inclination angle θ1. Furthermore, in a non-limiting example shown in FIG. 11 , the angle formed by the second land surface 33 and the surface S may be the second inclination angle θ2.

[0028] Here, the angle formed by the land surface 19 and the surface S may be evaluated at the point where the land surface 19 and the surface S intersect, or alternatively, another imaginary plane parallel to the surface S may be set and evaluated based on the intersection of this imaginary plane and the land surface 19.

[0029] The magnitude of the inclination angle of the land surface 19 may be 0° when the land surface 19 and the surface S are parallel, a positive angle formed on the side closer to the lower surface 5 than the surface S, and a negative angle formed on the side farther from the lower surface 5 than the surface S. In other words, when the land surface 19 approaches the lower surface 5 as it moves away from the cutting edge 9, the inclination angle of the land surface 19 may be a positive value, and when the land surface 19 moves away from the lower surface 5 as it moves away from the cutting edge 9, the inclination angle of the land surface 19 may be a negative value.

[0030] 9 to 11, the first tilt angle θ1 and the second tilt angle θ2 may be the same. Note that the first tilt angle θ1 and the second tilt angle θ2 being the same does not necessarily mean that the angles are the same in the strict sense, and a deviation of about 2° is acceptable.

[0031] When the insert 1 is used in cutting, the shapes of the first cutting edge 23 and the first corner cutting edge 27 used as a turning edge are easily transferred to the finished surface of the cut workpiece. When the insert 1 has the above-described configuration, the inclination angles of the cutting edges 9 from the first cutting edge 23 to the first corner cutting edge 27, i.e., the land surfaces 19 of the cutting edges 9 transferred to the finished surface, are the same. This makes it easy to obtain a good finished surface.

[0032] Furthermore, the first inclination angle θ1 and the second inclination angle θ2 may be constant. Note that the inclination angle of the land surface 19 being constant may also mean that the inclination angle is constant from the cutting edge 9 side of the land surface 19 to the rake face 20 side. In other words, in a cross section of the land surface 19 in a direction perpendicular to the cutting edge 9, the land surface 19 is represented by a straight line. Note that when the inclination angle of the land surface 19 is constant from the cutting edge 9 side to the rake face 20 side, the inclination angle does not have to be constant in the strict sense. There may be a deviation of about 2° from the cutting edge 9 side to the rake face 20 side.

[0033] Furthermore, the constant inclination angle of the land surface 19 may also mean that the inclination angle is constant from one boundary to the other boundary of the land surface 19. In other words, in a cross section of the land surface 19 in a direction parallel to the cutting edge 9, the land surface 19 is represented by a straight line parallel to the lower surface 5.

[0034] Note that when the inclination angle of the land surface 19 is constant from one boundary to the other boundary, the inclination angle does not have to be constant in the strict sense. A deviation of about 2° from one boundary to the other boundary is acceptable. In other words, when the land surface 19 is parallel to the lower surface 5 in a cross section of the land surface 19 in a direction parallel to the cutting edge 9, the parallelism does not have to be parallel in the strict sense, and a deviation of about 2° is acceptable.

[0035] In the following description, when it is said that the inclination angle of the land surface 19 is constant, the word "constant" is used in the above sense.

[0036] When the first inclination angle θ1 and the second inclination angle θ2 are constant, the finished surface tends to be good.

[0037] The first tilt angle θ1 and the second tilt angle θ2 may each be equal to or greater than 0°. In a non-limiting example shown in Figures 9A and 10A, the first tilt angle θ1 is 0°. Furthermore, in a non-limiting example shown in Figure 11A, the second tilt angle θ2 is 0°.

[0038] 9B and 10B, the first tilt angle θ1 is a positive value. Furthermore, in a non-limiting example shown in FIG. 11B, the second tilt angle θ2 is a positive value.

[0039] When the insert 1 has the above configuration, sharpness is easily ensured from the first cutting edge 23 to the first corner cutting edge 27. This makes it easy to obtain a good finished surface. The first inclination angle θ1 may be 0° to 5°. The second inclination angle θ2 may be 0° to 5°.

[0040] As a non-limiting example shown in Figure 3, the top surface 3 may have a second side 17. The second side 17 may be connected to the first corner 11. The second side 17 does not have to be a straight line in the strict sense, and may be, for example, a slightly curved convex or concave curve. Note that "slightly curved" means that the radius of curvature of the curved second side 17 is sufficiently large compared to the length of the second side 17, specifically, the radius of curvature of the second side 17 is 10 times or more the length of the second side 17.

[0041] As a non-limiting example shown in Figure 3, the cutting edge 9 may have a second cutting edge 25. The second cutting edge 25 may be located on the second side 17. The second cutting edge 25 may be used as a so-called main cutting edge.

[0042] As a non-limiting example shown in Fig. 3 , the land surface 19 may have a third land surface 35. The third land surface 35 may be located along the second cutting edge 25. Furthermore, the third land surface 35 may have a third region 35a. The third region 35a may be connected to the second land surface 33. Furthermore, as a non-limiting example shown in Fig. 12 , the angle formed by the third region 35a and the surface S may be defined as a third inclination angle θ3.

[0043] The third inclination angle θ3 may be the same as the second inclination angle θ2 at the boundary with the second land surface 33. Note that the inclination angles being the same do not necessarily have to be the same in the strict sense, and a deviation of about 2° is acceptable.

[0044] Furthermore, the third inclination angle θ3 may decrease with increasing distance from the second land surface 33. In the example shown in Figures 12 and 13, the third inclination angle θ3 in Figure 12, which is closer to the second land surface 33, is larger than the third inclination angle θ3 in Figure 13, which is farther from the second land surface 33. Specifically, the third inclination angle θ3 may vary from approximately 2° to approximately −20°.

[0045] When the insert 1 has the above-described configuration, the sharpness of the first corner cutting edge 27 is maintained while the strength of the portion of the second cutting edge 25 located along the third region 35a is likely to be increased. While the inclination angle of the third land surface 35 changes in the third region 35a, the second inclination angle θ2 does not change. Therefore, the first corner cutting edge 27 remains at a larger inclination angle, and the sharpness is likely to be maintained. Meanwhile, the strength of the third region 35a is increased due to the reduced inclination angle.

[0046] 3, the third land surface 35 may have a fourth region 35b. The fourth region 35b may be located farther from the second land surface 33 than the third region 35a.

[0047] 14 , the angle formed by the fourth region 35b and the plane S may be defined as the fourth inclination angle θ4. The fourth inclination angle θ4 may be smaller than 0°. Specifically, the fourth inclination angle θ4 may be approximately −20° to −15°.

[0048] When the insert 1 has the above-described configuration, the strength of the portion of the second cutting edge 25 located along the fourth region 35b is likely to be increased.

[0049] Furthermore, the fourth inclination angle θ4 may be constant. When the fourth inclination angle is constant, the strength of the portion of the second cutting edge 25 located along the fourth region 35b is likely to be further increased.

[0050] The width of the third land surface 35 in the direction perpendicular to the second side 17 may be constant. In other words, the width in the direction perpendicular to the second side 17 may be constant from the third region 35a to the fourth region 35b. Note that "constant width" does not necessarily mean that the width is constant in the strict sense. There may be a deviation of about 20% between the maximum and minimum width portions. The width of the third land surface 35 may be about 1.5 to 2 mm.

[0051] When the insert 1 has the above-described configuration, the strength of the cutting edge 9 is likely to be increased over the entire second cutting edge 25 .

[0052] Examples of materials for the insert 1 include inorganic materials such as cemented carbide, cermet, and ceramics. Examples of cemented carbide compositions include WC (tungsten carbide)-Co, WC-TiC (titanium carbide)-Co, and WC-TiC-TaC (tantalum carbide)-Co. WC, TiC, and TaC are hard particles, and Co is a binder phase. Cermet is a sintered composite material in which a ceramic component is combined with a metal. Specifically, examples of cermets include compounds whose main component is TiC or TiN (titanium nitride). However, the insert 1 is not limited to these materials.

[0053] The surface of the insert 1 may be coated with a coating layer by using a chemical vapor deposition (CVD) method or a physical vapor deposition (PVD) method. Examples of materials for the coating layer include aluminum oxide (alumina), titanium carbide, nitride, oxide, carbonate, oxynitride, and oxycarbonitride. The coating layer may contain only one of the above substances, or may contain multiple substances. The coating layer may be composed of only one layer, or may be composed of multiple layers stacked together. The materials for the coating layer are not limited to these.

[0054] <Cutting Tool> Next, a cutting tool 101 according to a non-limiting embodiment of the present disclosure will be described.

[0055] The cutting tool 101 is used for milling. As a non-limiting example shown in Figures 15 and 17, the cutting tool 101 may be rod-shaped and extend from a first end 103a to a second end 103b along a central axis O. Furthermore, as a non-limiting example shown in Figure 16, the cutting tool 101 may have a holder 103 having a pocket 105 (insert pocket) on the side of the first end 103a, and the insert 1 described above positioned in the pocket 105.

[0056] There may be only one pocket 105 or multiple pockets 105. In a non-limiting example shown in Figures 15 and 17, the holder 103 has multiple pockets 105. When the holder 103 has multiple pockets 105, the cutting tool 101 may include multiple inserts 1, with one insert located in each pocket 105.

[0057] The pocket 105 may be open to the outer peripheral surface and the end surface on the first end 103 a side of the holder 103. When the holder 103 has a plurality of pockets 105, these pockets 105 may be positioned at equal intervals or at unequal intervals around the central axis O.

[0058] The insert 1 may be mounted in the pocket 105 so that at least a portion of the insert 1 protrudes from the holder 103. Specifically, in a non-limiting example shown in Figures 15 to 17, the first cutting edge 23 protrudes from the holder 103 on the side of the first end 103a.

[0059] 3 and 4 , the upper surface 3 may have a second corner 13. The second corner 13 may be located on the opposite side of the first corner 11 across the first side 15. The second corner 13 may also be connected to the first side 15. When the insert 1 is installed in the pocket 105, the second corner 13 may be located closer to the central axis O than the first corner 11. Therefore, during cutting, the second cutting edge 25 connected to the first corner 11 is used as a main cutting edge, and the first corner cutting edge 27 and the first cutting edge 23 are used as cutting edges.

[0060] 3 to 5, the second point P2 may be a point where the radius of curvature changes between the second corner 13 and the first side 15. The second point P2 may be a boundary between the second corner 13 and the first side 15. Furthermore, as a non-limiting example shown in FIGS. 3 to 5, the second line L2 may be a virtual straight line extending from the second point P2 in a direction perpendicular to the first side 15. The second line L2 may be a boundary on the second corner 13 side of the first land surface 31.

[0061] 4 , the first region T1 may be the region where the width of the first land surface 31 in the direction perpendicular to the first edge 15 is smallest. In other words, the first region T1 may be the region where the first width W1 and the second width W2 are smallest. The cutting edge 9 located along the first region T1 may be the sharpest portion of the first cutting edge 23.

[0062] 4 , the center of the first side 15 may be set as the center M. The first part T1 may be located closer to the first corner 11 or the second corner 13 than the center M. The first part T1 may be located at the position farthest from the first corner 11 in the first region 31 a.

[0063] Furthermore, the first portion T1 may be the position in the second region 31b that is closest to the first corner 11. In other words, the first portion T1 may be the portion where the second width W2 is narrowest.

[0064] The first portion T1 may be located closer to the first corner 11 than to the center M. In other words, the portion of the first land surface 31 where the width in the direction perpendicular to the first edge 15 is smallest may be located closer to the first corner 11 than to the second corner 13.

[0065] When the cutting tool 101 is equipped with the insert 1 having the above-described configuration, the first portion T1 is located closer to the main cutting edge than the center M. In other words, the sharpest part of the first cutting edge 23 is located closer to the main cutting edge than the center M. Therefore, when the first cutting edge 23, which is closer to the main cutting edge than the center M, is used as a cutting edge, that is, when cutting at a low feed rate, a clean finished surface is likely to be obtained.

[0066] Moreover, the first portion T1 may be located closer to the second corner 13 than to the center M. In other words, the portion of the first land surface 31 where the width in the direction perpendicular to the first side 15 is smallest may be located closer to the second corner 13 than to the first corner 11.

[0067] When the cutting tool 101 is equipped with the insert 1 having the above-described configuration, the first portion T1 is located farther from the main cutting edge than the center M. In other words, the sharpest part of the first cutting edge 23 is located farther from the main cutting edge than the center M. Therefore, when the first cutting edge 23 located farther from the main cutting edge than the center M is used as a cutting edge, that is, when cutting at a high feed rate, a clean finished surface is likely to be obtained. Furthermore, because the thickness of the cutting edge near the main cutting edge can be ensured, the first cutting edge 23 is less likely to chip when cutting at a high feed rate.

[0068] Steel, cast iron, etc. may be used as the material of the holder 103. In particular, when steel is used among these materials, the holder 103 has high toughness.

[0069] <Method for Manufacturing Machined Product> Next, a method for manufacturing a machined product according to a non-limiting embodiment of the present disclosure will be described.

[0070] The machined product may be produced by machining the workpiece 201. A method for manufacturing a machined product in a non-limiting embodiment of the present disclosure may include the following steps: (1) a step of rotating the cutting tool 101; (2) a step of bringing the rotating cutting tool 101 into contact with the workpiece 201; and (3) a step of separating the cutting tool 101 from the workpiece 201.

[0071] More specifically, as shown in a non-limiting example in Fig. 18 , the cutting tool 101 may be brought relatively closer to the workpiece 201 while being rotated in the Y1 direction around the central axis O. Next, as shown in a non-limiting example in Fig. 19 , the cutting edge 9 of the cutting tool 101 may be brought into contact with the workpiece 201 to cut the workpiece 201. Then, as shown in a non-limiting example in Fig. 20 , the cutting tool 101 may be moved relatively away from the workpiece 201.

[0072] In a non-limiting example shown in Figure 18, the workpiece 201 is fixed and the cutting tool 101 is rotated in the Y1 direction around the central axis O, and the cutting tool 101 is moved in the Y2 direction to approach the workpiece 201. In a non-limiting example shown in Figure 20, the workpiece 201 is fixed and the cutting tool 101 is moved away. Note that in each step of the cutting process in the manufacturing method of the embodiment, the workpiece 201 is fixed and the cutting tool 101 is moved, but the present invention is not limited to this.

[0073] For example, in step (1), the workpiece 201 may be brought closer to the cutting tool 101. Similarly, in step (3), the workpiece 201 may be moved away from the cutting tool 101. When continuing the cutting process, the cutting tool 101 may be kept rotating, and the step of bringing the cutting edge 9 of the insert 1 into contact with different locations on the workpiece 201 may be repeated.

[0074] Examples of materials for the workpiece 201 include carbon steel, alloy steel, stainless steel, cast iron, and non-ferrous metals.

[0075] DESCRIPTION OF SYMBOLS 1...Cutting insert (insert) 3...First surface (upper surface) 5...Second surface (lower surface) 7...Third surface (side surface) 9...Cutting edge 11...First corner 13...Second corner 15...First edge 17...Second edge 19...Land surface 20...Rake face 21...Through hole 23...First cutting edge 25...Second cutting edge 27...First corner cutting edge 31...First land surface 31a...First region 31b...Second region 33...Second land surface 35...Third land surface 35a...Third region 35b...Fourth region 101...Cutting tool 103...Holder 103a...First end 103b...Second end 105...Pocket 201...Workpiece L1...First line L2...Second line M...Center of first edge O... Central axis of cutting tool P1... First point P2... Second point T1... First part W1... First width W2... Second width W3... Third width W4... Fourth width θ1... First inclination angle θ2... Second inclination angle θ3... Third inclination angle θ4... Fourth inclination angle

Claims

1. A cutting insert comprising: a first surface; a second surface located opposite the first surface; a third surface connected to the first surface and the second surface; and a cutting edge located at an intersection of the first surface and the third surface, wherein the first surface has a first corner, a first side connected to the first corner, and a land surface located along the cutting edge, wherein the cutting edge has a first cutting edge located on the first side, and the land surface has a first land surface located along the first cutting edge, and the first land surface has a first region and a second region located farther from the first corner than the first region, wherein the width of the first region in a direction perpendicular to the first side decreases with increasing distance from the first corner, and the width of the second region in a direction perpendicular to the first side increases with increasing distance from the first corner.

2. The cutting insert according to claim 1, wherein the cutting edge has a first corner cutting edge located at the first corner, the land surface has a second land surface located along the first corner cutting edge, and the inclination angles of the first land surface and the second land surface are the same.

3. The cutting insert according to claim 2, wherein the inclination angle of the first land surface and the second land surface is 0° or more.

4. A cutting insert according to claim 3, wherein the first surface has a second side connected to the first corner, the cutting edge has a second cutting edge located on the second side, the land surface has a third land surface located along the second cutting edge, the third land surface has a third region connected to the second land surface, and the inclination angle of the third region is the same as the inclination angle of the second land surface at the boundary with the second land surface and decreases with increasing distance from the second land surface.

5. The cutting insert according to claim 4, wherein the third land surface has a fourth region located farther from the second land surface than the third region, and the inclination angle of the fourth region is smaller than 0°.

6. The cutting insert according to claim 5, wherein the width of the third land surface in a direction perpendicular to the second side is constant.

7. A cutting tool comprising: a holder having a rod shape extending from a first end to a second end along a central axis and having a pocket located on the side of the first end; and a cutting insert according to any one of claims 1 to 6 located in the pocket, wherein the first cutting edge of the cutting insert protrudes from the holder on the side of the first end.

8. A cutting tool according to claim 7, wherein the first surface of the cutting insert has a second corner located on the opposite side of the first corner with the first side interposed therebetween, the second corner being located closer to the central axis than the first corner, and a portion of the first land surface at which the width in the direction perpendicular to the first side is smallest is located closer to the first corner than the second corner.

9. A cutting tool according to claim 7, wherein the first surface of the cutting insert has a second corner located on the opposite side of the first corner with the first side interposed therebetween, the second corner being located closer to the central axis than the first corner, and a portion of the first land surface at which the width in the direction perpendicular to the first side is smallest is located closer to the second corner than the first corner.

10. A method for manufacturing a machined product, comprising the steps of: rotating the cutting tool according to claim 7; bringing the rotating cutting tool into contact with a workpiece; and separating the cutting tool from the workpiece.

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