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

Abstract

A cutting insert according to one non-limiting aspect of the present disclosure comprises a cutting part having a first surface, a second surface, a third surface, a cutting blade, and a through-hole. The first surface has an inclined surface. The through-hole has one or more openings and one or more coolant holes. The coolant holes are each inclined increasingly away from the second surface as the distance to the corresponding opening increases.

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. 2024-031453, filed March 1, 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 (throw-away chips) are disclosed in U.S. Patent Application Publication No. 2013 / 0251463 (Patent Document 1), International Publication No. 2021 / 074979 (Patent Document 2), Japanese Utility Model Application Publication No. 03-033005 (Patent Document 3), and Japanese Patent Application Publication No. 04-183503 (Patent Document 4) as cutting tools used in cutting workpieces such as metals. The cutting insert disclosed in Patent Document 4 has a coolant supply hole formed from the side surface to the breaker surface.

[0004] In the cutting insert described in Patent Document 4, the coolant supply holes are not oriented toward the cutting edge of the cutting insert, which may reduce the cooling effect of the coolant on the cutting edge.

[0005] A non-limiting one-sided cutting insert of the present disclosure includes a cutting portion having a first surface, a second surface located opposite the first surface, a third surface connected to the first surface and the second surface, a cutting edge located at the intersection of the first surface and the third surface, and a through hole opening in the first surface. The first surface has an inclined surface that moves away from the second surface as it moves away from the cutting edge. The through hole has one or more openings that open in the inclined surface and one or more linear outflow holes extending from the openings. The outflow holes are inclined so as to move away from the second surface as they move away from the openings.

[0006] 1 is a perspective view showing an unlimited single-sided cutting insert according to the present disclosure; FIG. 1 is an enlarged view of region A1 shown in FIG. 1; FIG. 2 is the same enlarged view as FIG. 2; FIG. 1 is a top view of the cutting insert shown in FIG. 1, viewed from the B1 direction; FIG. 4 is an enlarged view of region A2 shown in FIG. 4; FIG. 5 is the same enlarged view as FIG. 5; FIG. 6 is a cross-sectional view taken along line VII-VII shown in FIG. 6; FIG. 7 is an enlarged view of region C1 shown in FIG. 7; FIG. 6 is a cross-sectional view taken along line IX-IX shown in FIG. 6; FIG. 9 is an enlarged view of region C2 shown in FIG. 9; FIG. 11 is a cross-sectional view taken along line XI-XI shown in FIG. 6; FIG. 12 is an enlarged view of region C3 shown in FIG. 11; FIG. 13 is a side view of the cutting insert shown in FIG. 1, viewed from the B2 direction; FIG. 14 is a perspective view showing an unlimited single-sided cutting tool according to the present disclosure; FIG. 15 is a schematic view showing one step in a method for manufacturing an unlimited single-sided machined product according to the present disclosure; FIG. 16 is a schematic view showing one step in a method for manufacturing an unlimited single-sided machined product according to the present disclosure; FIG. 17 is a schematic view showing one step in a method for manufacturing an unlimited single-sided machined product according 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 , the insert 1 may include a base portion 3 and a cutting portion 5. The base portion 3 and the cutting portion 5 may be formed separately or integrally. The portion including the base portion 3 and the cutting portion 5 may be defined as a main body.

[0009] The insert 1 may have a polygonal plate shape as a whole. The insert 1 in a non-limiting example shown in FIG. 1 has a generally rectangular plate shape. When the base portion 3 and the cutting portion 5 are configured as separate bodies, the base portion 3 may have a generally rectangular plate shape with some of the corners cut out. The cutting portion 5 may be joined to the cut-out portion using brazing material or the like. As in the non-limiting example shown in FIG. 1, the cutting portion 5 may have a generally triangular plate shape.

[0010] The base portion 3 and the cutting portion 5 are not limited to the above configurations. For example, the base portion 3 and the cutting portion 5 may each be a rectangular plate and have the same shape when viewed from above. For example, the cutting portion 5, which is also a rectangular plate, may be located on top of the base portion 3, which is also a rectangular plate.

[0011] 1 and 13, the base portion 3 may have an upper end surface 31, a lower end surface 33, and a hole 35. The hole 35 may be positioned so as to penetrate from the upper end surface 31 to the lower end surface 33. The hole 35 can be used as an insertion hole for a fastener when attaching the insert 1 to a holder. Examples of the fastener include a screw, a clamp member, and a wedge.

[0012] As a non-limiting example shown in Figure 2, the cutting portion 5 may have a first surface 7, a second surface 9, and a third surface 11. The second surface 9 may be located opposite the first surface 7. The third surface 11 may be located between the first surface 7 and the second surface 9. The first surface 7 may have a corner portion 13 and a first side 15. The first side 15 may be connected to the corner portion 13.

[0013] In a non-limiting example shown in Fig. 2 , the first surface 7 is located at the upper part of the cutting portion 5. Therefore, the first surface 7 may be conveniently referred to as the upper surface 7. In a non-limiting example shown in Fig. 2 , the second surface 9 is located at the lower part of the cutting portion 5. Therefore, the second surface 9 may be conveniently referred to as the lower surface 9. In a non-limiting example shown in Fig. 2 , the third surface 11 is located between the upper surface 7 and the lower surface 9 and is connected to these surfaces. Therefore, the third surface 11 may be conveniently referred to as the side surface 11.

[0014] The upper surface 7 may have any polygonal shape. As a non-limiting example shown in Figures 4 to 6, the upper surface 7 may have a triangular shape. There is no problem if the upper surface 7 has a square, pentagonal, hexagonal, or octagonal shape instead of a triangle.

[0015] The upper surface 7 may have a generally polygonal shape, but does not necessarily have to be a polygonal shape in the strict sense. That is, the corners of the polygonal upper surface 7 are not limited to the intersection of two straight lines, and may have a shape with a corner portion 13 that is rounded outward, as in the non-limiting example shown in Figures 2 and 3 . Furthermore, the first side 15 of the upper surface 7 does not necessarily have to be a straight line in the strict sense, and may be, for example, a slightly curved concave or convex curve. Note that "slightly curved" means that the radius of curvature of the curved first side 15 is sufficiently large relative 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.

[0016] The size of the cutting portion 5 is not particularly limited, but for example, the length of the first side 15 on the upper surface 7 may be set to about 0.4 to 2 mm. Also, the height from the upper surface 7 to the lower surface 9 may be set to about 0.8 to 2.5 mm.

[0017] As a non-limiting example shown in Figure 2, the cutting portion 5 may have a cutting edge 19 located at the intersection of the top surface 7 and the side surface 11. The cutting edge 19 may be used to cut a workpiece. The cutting edge 19 may be located over the entire intersection, or may be located only over a portion of the intersection. For example, the cutting edge 19 may be located at the corner portion 13 of the top surface 7 and a portion of the first side 15 continuing from the corner portion 13.

[0018] As a non-limiting example shown in Figures 2 and 5, the upper surface 7 may have an inclined surface 21. The inclined surface 21 may be located along the corner portion 13 and the first edge 15, and may be inclined so as to move away from the lower surface 9 as it moves away from the cutting edge 19. In other words, the inclined surface 21 may be inclined upward toward the inside of the upper surface 7. Furthermore, the inclined surface 21 may be a flat surface or a curved surface. The inclined surface 21 may be used to collide with and curve chips during cutting. In other words, the inclined surface 21 may be used as a so-called chip breaker.

[0019] As a non-limiting example shown in Figure 2, the cutting portion 5 may have a through hole 23. The through hole 23 may open on the upper surface 7. The through hole 23 may also be positioned so as to penetrate the interior of the cutting portion 5 from the upper surface 7 toward the base portion 3. Furthermore, the base portion 3 may have another through hole connected to the through hole 23 of the cutting portion 5. This through hole may be positioned inside the base portion 3.

[0020] The through-hole 23 may open at the inclined surface 21. In other words, the through-hole 23 may have an opening 25 that opens at the inclined surface 21. There may be only one opening 25, or there may be multiple openings 25. The position of the opening 25 on the inclined surface 21 is not limited to a specific location and may be located at any location.

[0021] A coolant (cooling fluid) for cooling the insert 1 during cutting can be passed through the through hole 23 in the cutting portion 5 and the through hole in the base portion 3. The opening of the through hole in the base portion 3 can function as an inlet through which coolant flows in (is supplied) from the outside, and the opening 25 of the through hole 23 can function as an outlet through which the coolant flows out during cutting. In this case, the through hole 23 in the cutting portion 5 and the through hole in the base portion 3 can be collectively positioned as a coolant flow path.

[0022] Examples of coolants include water-insoluble oils and water-soluble oils. Examples of water-insoluble oils include cutting oils such as oil-based, inactive extreme pressure, and active extreme pressure types. Examples of water-soluble oils include cutting oils such as emulsions, solubles, and solutions. The coolant is not limited to a liquid, and may be a gas such as an inert gas. The coolant may be appropriately selected and used depending on the material of the workpiece.

[0023] The through holes 23 may be formed by, for example, drilling or laser processing a member that will become the cutting portion 5 to form a hole. Alternatively, the insert may be fabricated using metal additive manufacturing or the like so that the hole is formed in the insert from the beginning. The through holes 23 may be formed as the portions of the holes through which the coolant flows. Each hole may have, for example, a circular, elliptical, or polygonal shape in a cross section perpendicular to the direction of fluid flow. Portions of the holes formed by drilling that do not function as portions through which the coolant flows may be blocked with a sealing member to prevent fluid leakage. Examples of sealing members include solder, resin, and screw members.

[0024] 2 and 3, the through-hole 23 is configured by a linearly extending portion, but is not limited thereto. For example, the through-hole 23 may be configured to have a portion that extends linearly from the opening 25 and another portion that is connected to the first portion and is inclined relative to the first portion. Here, the other portion may be linear or curved.

[0025] The coolant flow path has an inlet hole 27 through which the coolant flows in and an outlet hole 29 through which the coolant flows out. As described above, the through hole 23 is a portion of the coolant flow path that is located in the cutting portion 5. In the non-limiting example shown in Figures 2 and 3, the through hole 23 is configured by a portion that extends linearly, and therefore, this linear portion can be evaluated as the through hole 23 and the outlet hole 29.

[0026] 2 and 3, the base portion 3 has another through-hole connected to the through-hole 23. This through-hole can be considered to be an inlet hole 27 in the coolant flow path.

[0027] 2 and 3 , the inlet hole 27 extends linearly from the upper end surface 31 of the base portion 3 toward the lower end surface 33, and opens at the lower end surface 33. The opening at the lower end surface 33 can function as an inlet through which coolant flows in from the outside. When the inlet hole 27 is linear, the pressure loss of the coolant flowing through the inlet hole 27 is small.

[0028] The straight line and curved line used here do not represent one-dimensional lines, but simply represent the state in which the hole extends straight or curved. In the following description, the "straight line" and "curve" used for the through-hole 23, the inlet hole 27, or the outlet hole 29 have the same meaning.

[0029] 2 and 3, the outflow hole 29 may be connected to the openings 25 opening in the inclined surface 21. There may be only one outflow hole 29, or there may be multiple outflow holes 29. The number of outflow holes 29 may be the same as the number of openings 25.

[0030] Alternatively, the outlet hole 29 may extend linearly from the opening 25. With this configuration, the coolant flowing out from the opening 25 flows in the same direction as the extension direction of the outlet hole 29. In other words, it is easy to control the outflow direction of the coolant by the extension direction of the outlet hole 29. Furthermore, when the outlet hole 29 is linear, the pressure loss of the coolant flowing inside the outlet hole 29 is small.

[0031] 7-12 , the outflow holes 29 may be angled away from the lower surface 9 as they move away from the opening 25. That is, the outflow holes 29 may be angled downward toward the cutting edge 19.

[0032] When the insert 1 has the above-described configuration, the coolant discharged from the opening 25 is easily supplied to the vicinity of the cutting edge. Therefore, the coolant can easily cool the cutting edge 19.

[0033] The through-hole 23 may have two or more openings 25 that open on the inclined surface 21. Furthermore, the through-hole 23 may have two or more linear outflow holes 29 that extend from each opening 25. The number of openings 25 and the number of outflow holes 29 may be the same. In one non-limiting example shown in Figures 2, 3 and 5, three openings 25 and three outflow holes 29 connected to each opening 25 are shown.

[0034] When the insert 1 has the above configuration, the coolant can be more easily discharged over a wider area than when there is only one opening 25 and one outlet hole 29. This makes it easier to cool a wider area of ​​the cutting edge 19 and achieve a high cooling effect. The number of openings 25 may be eight or less, and the number of outlet holes 29 may be eight or less.

[0035] As shown in Figures 2 and 5 as a non-limiting example, the top surface 7 may have a second side 17 connected to the corner portion 13. The second side 17 does not have to be a straight line in the strict sense, and may be a slightly curved concave or convex curve, similar to the first side 15. As shown in Figures 5 and 6 as a non-limiting example, when the top surface 7 is viewed from the front, the first side 15 is located on the right and the second side 17 is located on the left. However, the positional relationship between the first side 15 and the second side 17 is not limited. The positional relationship between the first side 15 and the second side 17 may be reversed. In the following description, the front view of the top surface 7 may be referred to as a top view.

[0036] 3, 5, and 6, the cutting edge 19 may include a first cutting edge 19a, a second cutting edge 19b, and a corner cutting edge 19c. The corner cutting edge 19c may be located over the entire corner portion 13. The corner cutting edge 19c may also be referred to as a third cutting edge 19c.

[0037] The first cutting edge 19 a may be located over the entire first side 15, or may be located only in a partial region adjacent to the corner cutting edge 19 c. During cutting such as external diameter machining or internal diameter machining, the first cutting edge 19 a may be used as a main cutting edge.

[0038] The second cutting edge 19b may be located over the entire second side 17, or may be located only in a partial region adjacent to the corner cutting edge 19c. During cutting such as external diameter machining or internal diameter machining, the second cutting edge 19b may be used as a main cutting edge.

[0039] 5 and 6, when viewed from above, the first cutting edge 19a is located on the right and the second cutting edge 19b is located on the left. However, the positional relationship between the first cutting edge 19a and the second cutting edge 19b is not limited. There is no problem even if the positional relationship between the first cutting edge 19a and the second cutting edge 19b is reversed.

[0040] 3, 5, and 6, the opening 25 may have a first opening 25a, a second opening 25b, and a third opening 25c. The first opening 25a may be open toward the first cutting edge 19a on the inclined surface 21. The second opening 25b may be open toward the second cutting edge 19b on the inclined surface 21. The third opening 25c may be open toward the corner cutting edge 19c on the inclined surface 21.

[0041] 5 and 7 to 12, the outlet holes 29 may include a first outlet hole 29a extending from the first opening 25a, a second outlet hole 29b extending from the second opening 25b, and a third outlet hole 29c extending from the third opening 25c. In other words, the outlet holes 29 may include the first outlet hole 29a connected to the first opening 25a, the second outlet hole 29b connected to the second opening 25b, and the third outlet hole 29c connected to the third opening 25c. Each hole may extend linearly.

[0042] 5 and 6, the outlet holes 29 may branch out and extend from the inlet holes 27. Specifically, the first outlet hole 29a may extend from the inlet hole 27 toward the first opening 25a, the second outlet hole 29b may extend from the inlet hole 27 toward the second opening 25b, and the third outlet hole 29c may extend from the inlet hole 27 toward the third opening 29c.

[0043] 7 and 8, the first outlet holes 29a may be inclined away from the lower surface 9 as they move away from the first opening 25a. In other words, the first outlet holes 29a may be inclined downward toward the first cutting edge 19a.

[0044] 5, in a top view, an extension line of the central axis L1 of the first outlet hole 29a may intersect with the first cutting edge 19a. In this case, the first opening 25a connected to the first outlet hole 29a may be open toward the first cutting edge 19a.

[0045] 9 and 10 , the second outlet holes 29b may be inclined away from the lower surface 9 as they move away from the second opening 25b. In other words, the second outlet holes 29b may be inclined downward toward the second cutting edge 19b.

[0046] 5, in a top view, an extension line of the central axis L2 of the second outlet hole 29b may intersect with the second cutting edge 19b. In this case, the second opening 25b connected to the second outlet hole 29b may be open toward the second cutting edge 19b.

[0047] 11 and 12, the third outlet holes 29c may be inclined away from the lower surface 9 as they move away from the third opening 25c. In other words, the third outlet holes 29c may be inclined downward toward the corner cutting edge 19c.

[0048] 5, an extension of the central axis L3 of the third outlet hole 29c may intersect with the corner cutting edge 19c in a top view. In this case, the third opening 25c connected to the third outlet hole 29c may be open toward the corner cutting edge 19c.

[0049] When the insert 1 has the above-described configuration, coolant can be easily supplied to each of the first cutting edge 19 a, the second cutting edge 19 b, and the corner cutting edge 19 c. As a result, each cutting edge can be easily cooled, and the cooling effect can be easily improved.

[0050] 8, 10, and 12, the inner diameter of the first outlet hole 29a may be D1, the inner diameter of the second outlet hole 29b may be D2, and the inner diameter of the third outlet hole 29c may be D3. The inner diameter D1 of the first outlet hole 29a may be set to approximately 0.05 to 0.15 mm. The inner diameter D2 of the second outlet hole 29b may be set to approximately 0.05 to 0.15 mm. The inner diameter D3 of the third outlet hole 29c may be set to approximately 0.03 to 0.1 mm.

[0051] The inner diameter D1 of the first outlet hole 29a may be larger than the inner diameter D3 of the third outlet hole 29c. The inner diameter D2 of the second outlet hole 29b may be larger than the inner diameter D3 of the third outlet hole 29c. When the inner diameters D1, D2, and D3 satisfy the above relationship, the inner diameter D1 of the first outlet hole 29a may be set to approximately 0.1 to 0.15 mm. The inner diameter D2 of the second outlet hole 29b may be set to approximately 0.1 to 0.15 mm. The inner diameter D3 of the third outlet hole 29c may be set to approximately 0.03 to 0.08 mm.

[0052] When the insert 1 has the above-described configuration, more coolant is likely to be supplied to the portions used as so-called main cutting edges, such as the first cutting edge 19 a and the second cutting edge 19 b, which are therefore more efficiently cooled during cutting, as the main cutting edges have a large cutting resistance and generate a lot of heat.

[0053] An imaginary plane including the cutting edge 19 and parallel to the lower surface 9 may be defined as the surface S. The angle formed by the outflow hole 29 with the surface S may be defined as the inclination angle. In other words, the angle of the outflow hole 29 inclined with respect to the lower surface 9 may be defined as the inclination angle. Specifically, as in a non-limiting example shown in FIG. 8 , the angle formed by the first outflow hole 29a with the surface S may be defined as the first inclination angle θ1. Similar to the first inclination angle θ1, the angle formed by the second outflow hole 29b with the surface S may be defined as the second inclination angle θ2, and the angle formed by the third outflow hole 29c with the surface S may be defined as the third inclination angle θ3.

[0054] Here, the angle that each outlet hole 29 makes with the surface S does not only refer to the angle formed at the point where the outlet hole 29 intersects with the surface S. If the outlet hole 29 does not intersect with the surface S, the angle formed by the intersection of the extension line of the central axis L of the outlet hole 29 and the surface S may also be the angle formed by the outlet hole 29 and the surface S.

[0055] The first tilt angle θ1 may be 2° to 6°. The second tilt angle θ2 may be 2° to 6°. The third tilt angle θ3 may be 1° to 4°. The first tilt angle θ1 and the second tilt angle θ2 may each be different from the third tilt angle θ3.

[0056] When the insert 1 has the above-described configuration, it is easy to adjust the positions to which the coolant is supplied from each opening, and the coolant can be reliably supplied to the vicinity of the cutting edge 19. Therefore, a higher cooling effect can be easily obtained.

[0057] As a non-limiting example shown in Figure 5, when viewed from above, the width from the first cutting edge 19a to the first opening 25a in a direction along the central axis L1 of the first outlet hole 29a may be defined as a first length W1, the width from the second cutting edge 19b to the second opening 25b in a direction along the central axis L2 of the second outlet hole 29b may be defined as a second length W2, and the width from the corner cutting edge 19c to the third opening 25c in a direction along the central axis L3 of the third outlet hole 29c may be defined as a third length W3.

[0058] The third length W3 may be greater than the first length W1 and the second length W2. That is, the distance required to supply coolant from the third opening 25c to the corner cutting edge 19c may be greater than the distance required to supply coolant from the first opening 25a and the second opening 25b to the first cutting edge 19a and the second cutting edge 19b, respectively.

[0059] In order to supply the coolant over a longer distance, it is preferable that the inclination angle of the outlet hole 29 is small. Therefore, the third inclination angle θ3 may be smaller than the first inclination angle θ1 and the second inclination angle θ2. In other words, the first inclination angle θ1 and the second inclination angle θ2 may each be larger than the third inclination angle θ3.

[0060] When the insert 1 has the above-described configuration, the coolant discharged from each opening 25 is more likely to be supplied to the vicinity of each cutting edge more accurately.

[0061] As shown in a non-limiting example in Fig. 8, the height from the lower surface 9 to the center of the first opening 25a may be defined as a first height H1. As shown in a non-limiting example in Fig. 10, the height from the lower surface 9 to the center of the second opening 25b may be defined as a second height H2. As shown in a non-limiting example in Fig. 12, the height from the lower surface 9 to the center of the third opening 25c may be defined as a third height H3.

[0062] The center of each opening may be the central axis of the outlet hole 29 to which the opening is connected or the point where the openings intersect. Specifically, the center of the first opening 25a may be the point where the central axis L1 of the first outlet hole 29a intersects with the first opening 25a. Centers may be set similarly for the second opening 25b and the third opening 25c.

[0063] The first height H1 and the second height H2 may be different from the third height H3. When the insert 1 has the above-described configuration, it is easy to adjust the positions to which the coolant is supplied from each opening, and it is easy to reliably supply the coolant near the cutting edge 19. Therefore, it is easy to obtain a higher cooling effect.

[0064] 5, the first length W1 and the second length W2 may be smaller than the third length W3, so that the distance required to supply coolant from the third opening 25c to the corner cutting edge 19c may be longer than the distance required to supply coolant from the first opening 25a to the first cutting edge 19a and the distance required to supply coolant from the second opening 25b to the second cutting edge 19b.

[0065] In order to supply the coolant over a longer distance, it is preferable that the height from the lower surface 9 to the opening 25 is large. Therefore, the third height H3 may be larger than the first height H1 and the second height H2. In other words, the first height H1 and the second height H2 may be smaller than the third height H3.

[0066] When the insert 1 has the above-described configuration, the coolant discharged from each opening is more likely to be supplied to the vicinity of each cutting edge more accurately.

[0067] The opening 25 may have a shape with a major axis and a minor axis. Note that the major axis and minor axis here may be different from the major axis and minor axis used to define an ellipse. The major axis may be the longest line segment passing through the center of the shape and bounded by the periphery of the shape. The minor axis may be the shortest line segment passing through the center of the shape and bounded by the periphery of the shape.

[0068] 5, when viewed from above, if the width of the opening 25 in the direction along the central axis L of the outlet hole 29 is defined as a first width G1, this first width G1 corresponds to the major axis. Also, if the width of the opening 25 in the direction perpendicular to the central axis L of the outlet hole 29 is defined as a second width G2, this second width G2 corresponds to the minor axis.

[0069] In the non-limiting example shown in Fig. 5, the first width G1 is the major axis and the second width G2 is the minor axis, but there is no problem if the opening 25 has a shape in which the first width G1 is the minor axis and the second width G2 is the major axis. The opening 25 only needs to have different sizes for the first width G1 and the second width G2. Furthermore, in the non-limiting example shown in Fig. 5, the major axis and the minor axis are orthogonal to each other, but the shape may be such that they are not orthogonal to each other.

[0070] When the insert 1 has the above-described configuration, the pressure loss of the coolant flowing out from the opening 25 tends to be small. In other words, the coolant flows more easily than when the opening 25 is simply circular.

[0071] 5 , in a non-limiting example, the width of the opening 25 in a direction along the central axis L of the outlet hole 29 may be larger than the width of the opening 25 in a direction perpendicular to the central axis L of the outlet hole 29 in a front view (top view) of the first surface 7. That is, in a top view, the first width G1 may be larger than the second width G2. Note that the second width G2 may be perpendicular to the first width G1 at the center of the first width G1.

[0072] When the insert 1 has the above-described configuration, it is easy to reduce the pressure loss of the coolant flowing out from the opening 25. Furthermore, since the second width G2 is smaller and the coolant flows out in a vertically long shape, the coolant not only cools the cutting edge 19 but also makes it easier to remove chips.

[0073] When the main body including the base portion 3 and the cutting portion 5 is integrally formed, examples of the material for the main body (the base portion 3 and the cutting portion 5) 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 main body is not limited to these materials.

[0074] When the base portion 3 and the cutting portion 5 are formed as separate bodies, the base portion 3 and the cutting portion 5 may be made of different materials. Examples of the material of the base portion 3 include inorganic materials such as cemented carbide, cermet, and ceramics. The compositions of the cemented carbide and cermet are the same as those in the above examples. However, the material of the base portion 3 is not limited to these.

[0075] Examples of materials for the cutting portion 5 include cubic boron nitride (cBN) and diamond. Examples of diamond include polycrystalline diamond (PCD). Furthermore, the cutting portion 5 may contain materials other than these materials as long as they contain these materials as the main component. Note that the term "main component" here means the component with the largest content ratio by mass. However, the cutting portion 5 is not limited to these materials.

[0076] The insert 1 may also be configured to include a main body containing the above-mentioned materials and a coating layer that coats the main body. 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-mentioned materials, or may contain multiple materials. The coating layer may be configured with only one layer, or may be configured with multiple layers stacked together. Note that the materials for the coating layer are not limited to these.

[0077] The coating layer may be deposited on the body by chemical vapor deposition (CVD) or physical vapor deposition (PVD). For example, if the coating layer is deposited by the vapor deposition method while the body is held at the inner periphery of the hole 35, the coating layer is likely to cover the entire surface of the body except for the inner periphery of the hole 35.

[0078] <Cutting Tool> Next, a cutting tool 101 according to a non-limiting embodiment of the present disclosure will be described.

[0079] The cutting tool 101 may have a holder 103 extending from a first end 103a to a second end 103b and having a pocket 105 (insert pocket) on the side of the first end 103a, as shown in a non-limiting example in Figure 14, and the above-mentioned insert 1 positioned in the pocket 105.

[0080] 14, the holder 103 may be rod-shaped. The pocket 105 may be a portion where the insert 1 is attached. In this case, the base portion 3 of the insert 1 may be in direct contact with the pocket 105.

[0081] As a non-limiting example shown in FIG. 14 , the insert 1 may be mounted so that at least a part of the portion used as the cutting edge 19 in the cutting portion 5 protrudes outward from the holder 103 .

[0082] 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.

[0083] 14 shows a non-limiting example of a cutting tool used for so-called turning. Examples of turning include external diameter machining, internal diameter machining, end face machining, and grooving. The cutting tool is not limited to that used for turning. For example, the insert 1 of the above embodiment may be used in a cutting tool used for milling.

[0084] <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.

[0085] The machined product can be produced by cutting 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 workpiece 201; (2) a step of bringing a cutting tool 101, such as that typified by the above-described embodiment, into contact with the rotating workpiece; and (3) a step of separating the cutting tool 101 from the workpiece 201.

[0086] More specifically, first, as in a non-limiting example shown in Fig. 15 , the workpiece 201 may be rotated around the axis O while the cutting tool 101 is brought relatively close to the workpiece 201. Next, as in a non-limiting example shown in Fig. 16 , the ridge line (cutting edge 19) of the cutting tool 101 may be brought into contact with the workpiece 201 to cut the workpiece 201. Then, as in a non-limiting example shown in Fig. 17 , the cutting tool 101 may be moved relatively away from the workpiece 201.

[0087] In a non-limiting example shown in Fig. 15, the axis O is fixed and the workpiece 201 is rotated around the axis O while the cutting tool 101 is moved in the Y1 direction to approach the workpiece 201. In a non-limiting example shown in Fig. 16, at least a portion of the corner portion 13 and the first edge 15 of the insert 1 that are used as the cutting edge 19 is brought into contact with the rotating workpiece 201, and the insert 1 is moved in the X1 direction to cut the workpiece 201. In a non-limiting example shown in Fig. 17, the cutting tool 101 is moved in the Y2 direction while the workpiece 201 is being rotated to move away from the workpiece 201.

[0088] In the cutting process in the manufacturing method of the embodiment, the cutting tool 101 is moved in each step to bring the cutting tool 101 into contact with the workpiece 201 or to move the cutting tool 101 away from the workpiece 201, but of course, this is not limited to this form.

[0089] 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 workpiece 201 may be kept rotating, and the step of bringing the cutting edge 19 of the insert 1 into contact with different locations on the workpiece 201 may be repeated.

[0090] Examples of materials for the workpiece 201 include hardened steel, carbon steel, alloy steel, stainless steel, cast iron, and non-ferrous metals.

[0091] DESCRIPTION OF SYMBOLS 1... Cutting insert (insert) 3... Base portion 5... Cutting portion 7... First surface (upper surface) 9... Second surface (lower surface) 11... Third surface (side surface) 13... Corner portion 15... First edge 17... Second edge 19... Cutting edge 19a... First cutting edge 19b... Second cutting edge 19c... Corner cutting edge (third cutting edge) 21... Inclined surface 23... Through hole 25... Opening 25a... First opening 25b... Second opening 25c... Third opening 27... Inlet hole 29... Outlet hole 29a... First outlet hole 29b... Second outlet hole 29c... Third outlet hole 31... Upper end surface 33... Lower end surface 35... Hole 101... Cutting tool 103... Holder 103a... First end 103b: Second end 105: Pocket (insert pocket) 201: Workpiece D1: Inner diameter of first outlet hole D2: Inner diameter of second outlet hole D3: Inner diameter of third outlet hole G1: First width G2: Second width H1: First height H2: Second height H3: Third height L: Central axis of outlet hole L1: Central axis of first outlet hole L2: Central axis of second outlet hole L3: Central axis of third outlet hole O: Rotation axis of workpiece W1: First length W2: Second length W3: Third length θ1: First inclination angle θ2: Second inclination angle θ3: Third inclination angle

Claims

1. A cutting insert comprising: a cutting portion having: a first surface; a second surface located opposite the first surface; a third surface connected to the first surface and the second surface; a cutting edge located at the intersection of the first surface and the third surface; and a through hole opening in the first surface, wherein the first surface has an inclined surface that moves away from the second surface as it moves away from the cutting edge, and the through hole has one or more openings that open in the inclined surface and one or more straight outflow holes extending from the openings, and the outflow holes are inclined so as to move away from the second surface as they move away from the openings.

2. The cutting insert according to claim 1, wherein the through hole has two or more openings that open on the inclined surface, and two or more outlet holes that are linear and extend from the openings, respectively.

3. The cutting insert according to claim 1, wherein the first surface has a corner portion, a first side connected to the corner portion, and a second side connected to the corner portion; the cutting edges have a first cutting edge located on the first side, a second cutting edge located on the second side, and a corner cutting edge located at the corner portion; the openings have a first opening opening toward the first cutting edge, a second opening opening toward the second cutting edge, and a third opening opening toward the corner cutting edge; the outflow holes have a first outflow hole extending from the first opening, a second outflow hole extending from the second opening, and a third outflow hole extending from the third opening; the first outflow hole inclines so as to move away from the second surface as it moves away from the first opening; the second outflow hole inclines so as to move away from the second surface as it moves away from the second opening; and the third outflow hole inclines so as to move away from the second surface as it moves away from the third opening.

4. The cutting insert according to claim 3, wherein the inner diameters of the first outlet hole and the second outlet hole are each larger than the inner diameter of the third outlet hole.

5. The cutting insert according to claim 4, wherein the inclination angles of the first outlet hole and the second outlet hole are different from the inclination angle of the third outlet hole.

6. The cutting insert according to claim 5, wherein the inclination angles of the first outlet hole and the second outlet hole are each greater than the inclination angle of the third outlet hole.

7. The cutting insert according to claim 4, wherein the height from the second surface to the center of the first opening and the height from the second surface to the center of the second opening are different from the height from the second surface to the center of the third opening.

8. The cutting insert according to claim 7, wherein the height from the second surface to the center of the first opening and the height from the second surface to the center of the second opening are lower than the height from the second surface to the center of the third opening.

9. The cutting insert of claim 1, wherein the opening has a shape with a major axis and a minor axis.

10. A cutting insert according to claim 9, wherein, in a front view of the first surface, the width of the opening in a direction along the central axis of the outlet hole is larger than the width of the opening in a direction perpendicular to the central axis of the outlet hole.

11. A cutting tool comprising: a holder extending from a first end toward a second end and having a pocket located on the side of the first end; and a cutting insert according to any one of claims 1 to 10 located in the pocket.

12. A method for manufacturing a machined product, comprising the steps of: rotating a workpiece; bringing the cutting tool according to claim 11 into contact with the rotating workpiece; and separating the cutting tool from the workpiece.

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