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

Abstract

A cutting insert based on one embodiment of the present disclosure has a cutting part having a first surface, a second surface, a third surface positioned between the first and second surfaces, and a flow path extending from the first surface toward the second surface. The flow path has an outflow port that opens in the first surface, and a first flow path that extends from the outflow port toward the second surface. In a first cross-section that passes through the central axis of the first flow path and is orthogonal to the first surface, the width of the first flow path in a direction parallel to the first surface increases with increasing distance from the first surface.

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. 2022-151559, filed on September 22, 2022, the entire disclosure of which is incorporated herein by reference.

[0002] The present aspect relates to a method for manufacturing a cutting insert, a cutting tool, and a machined product.

[0003] Known cutting inserts for cutting tools used when cutting a workpiece include those described in, for example, Japanese Patent Laid-Open No. 5-116008 (Patent Document 1) and International Publication No. 2021 / 074979 (Patent Document 2). The cutting inserts described in Patent Documents 1 and 2 have a flow path therein through which a coolant flows to cool the cutting insert.

[0004] By providing a flow path inside the cutting insert, coolant can be efficiently supplied to the cutting edge during cutting, thereby improving the durability of the cutting insert.

[0005] When a flow path is provided inside the cutting insert, it is required to more efficiently supply coolant to the cutting edge during cutting.

[0006] A cutting insert according to one aspect of the present disclosure has a cutting portion including a first surface having a rake face region, a second surface located opposite the first surface, a third surface located between the first surface and the second surface and having a flank region, and a flow passage extending from the first surface toward the second surface. The flow passage has an outlet opening in the first surface and a first flow passage extending from the outlet toward the second surface. In a first cross section passing through a central axis of the first flow passage and perpendicular to the first surface, the width of the first flow passage in a direction parallel to the first surface increases with increasing distance from the first surface.

[0007] 1. A perspective view showing a cutting insert according to a first embodiment. 2. A plan view of the cutting insert shown in FIG. 1, as seen from direction A1. 3. An enlarged view of region B1 shown in FIG. 1. 4. An enlarged view of region B2 shown in FIG. 2. 5. An enlarged view of a V-V cross section shown in FIG. 4. 6. A view showing a modification of a first flow path of the cutting insert according to the first embodiment, corresponding to FIG. 5. 7. An enlarged view of region B3 shown in FIG. 5. 8. An enlarged view of a VII-VII cross section shown in FIGS. 4 and 5. 9. An enlarged view of a VIII-VIII cross section shown in FIGS. 4 and 5. 10. An enlarged view of a cutting insert according to a second embodiment, corresponding to FIG. 3. 11. An enlarged view of a cutting insert according to a second embodiment, corresponding to FIG. 4. 12. An enlarged view of a XI-XI cross section shown in FIG. 11, corresponding to FIG. 5. 13. An enlarged view of a XII-XII cross section shown in FIGS. 11 and 12, corresponding to FIG. 8. 14. An enlarged view of a XIII-XIII cross section shown in FIGS. 11 and 12, corresponding to FIG. 9. 15. A side view of a cutting tool according to an embodiment of the present disclosure. 16. A view showing a step in a method of manufacturing a machined product according to an embodiment of the present disclosure. 17. A view showing a step in a method of manufacturing a machined product according to an embodiment of the present disclosure. 1 is a diagram illustrating a step in a method for manufacturing a machined product according to an embodiment of the present disclosure.

[0008] <Cutting Insert> Cutting inserts (hereinafter, sometimes referred to as inserts) according to non-limiting embodiments of the present disclosure will be described in detail below with reference to the drawings. Specifically, cutting inserts according to first and second embodiments will be described in detail with reference to the drawings. However, for the sake of convenience, the drawings referred to below show only the main components necessary for explaining the inserts according to the respective embodiments in a simplified form. Therefore, the inserts according to 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 actual dimensions of the components, the dimensional ratios of the components, etc.

[0009] The insert according to the first embodiment will be described as insert 1A, and the insert according to the second embodiment will be described as insert 1B, but when describing the common configuration between the two, for convenience of explanation, insert 1A and insert 1B will be referred to as insert 1.

[0010] As a non-limiting example shown in Figure 1, the insert 1A according to the first embodiment has a first surface 3 (top surface), a second surface 5 (bottom surface) located opposite the first surface 3, and a third surface 7 (side surface) located between the first surface 3 and the second surface 5.

[0011] The first surface 3 and the second surface 5 are polygonal, and in the non-limiting example shown in Fig. 2, they are rhombic. Therefore, the first surface 3 in the non-limiting example shown in Fig. 2 has four corners 9 and four sides 11. Furthermore, in the non-limiting example shown in Fig. 2, the third surface 7 has four faces, and each face is approximately rectangular.

[0012] In the non-limiting example shown in Figure 2, the first surface 3 has multiple corners 9 and multiple sides 11. Specifically, the first surface 3 has a first corner 9A, a second corner 9B, and a third corner 9C. The first corner 9A is one of the multiple corners 9. The second corner 9B and the third corner 9C are each located adjacent to the first corner 9A among the multiple corners 9. The first surface 3 also has a first side 11A extending from the first corner 9A to the second corner 9B, and a second side 11B extending from the first corner 9A to the third corner 9C.

[0013] 2 is a plan view of the cutting insert 1A shown in FIG. 1 as viewed from the A1 direction, and is a view showing the first surface 3 as viewed from the front. Hereinafter, the front view of the first surface 3 may be referred to as a top view. In FIG. 2, the second corner 9B is located on the right side of the insert 1, and the third corner 3C is located on the left side of the insert 1, but they may be reversed.

[0014] 2, when the insert 1 is viewed from above, each corner 9 has a curved shape, and the radius of curvature of each corner 9 may be constant, for example. Also, in the non-limiting example shown in FIG. 2, when the insert 1 is viewed from above, each side 11 has a straight line shape.

[0015] The insert 1 also has cutting edges 13. In a non-limiting example shown in Fig. 2, the cutting edges 13 include a first cutting edge 13A located along a portion of the first side 11A, a second cutting edge 13B located along a portion of the second side 11B, and a first corner cutting edge 13C located along the entire first corner 9A.

[0016] In a non-limiting example shown in Figure 3, the first cutting edge 13A and the second cutting edge 13B are located along the first side 11A and the second side 11B, respectively, and therefore have a linear shape. The first corner cutting edge 13C is located along the first corner 9A and therefore has a curved shape. In this case, the radius of curvature of the first corner cutting edge 13C may be constant. Also, in a non-limiting example shown in Figure 3, the insert 1 has the cutting edge 13 between the first surface 3 and the third surface 7, and therefore the first surface 3 has a rake face region 15, and the third surface 7 has a flank region 17.

[0017] In a non-limiting example shown in Fig. 3, the insert 1 has a land surface 19 located between the first surface 3 and the third surface 7. Here, the land surface 19 is a strip-shaped surface area provided along the cutting edge 13 to suppress chipping of the cutting edge 13. In a non-limiting example shown in Fig. 2, for convenience of manufacturing, the insert 1 has a surface of the same shape as the land surface 19 in a portion where the cutting edge 13 is not located.

[0018] The cutting edge 13 may be located at the intersection of the first surface 3 and the third surface 7, but is not limited to this. For example, as described above, if the insert 1 has the land surface 19 or a surface with a shape similar to that of the land surface 19, the cutting edge 13 may be located at the intersection of the land surface 19 and the third surface 7.

[0019] Although the size of the insert 1 is not particularly limited, for example, in the insert 1A according to the first embodiment, the length of the first side 11A is set to 3 to 20 mm, and the height from the first surface 3 to the second surface 5 is set to 2 to 20 mm.

[0020] 1, the insert 1 has a through hole 21 that opens to the first surface 3 and the second surface 5. The through hole 21 is used as a hole into which a fastener is inserted when the insert 11 is attached to a holder. Examples of the fastener include a screw, a clamp member, and a wedge.

[0021] Furthermore, the through-hole 21 is not limited to the above configuration, and may, for example, be open to the third surface 7. In this case, the through-hole may penetrate from one surface region of the third surface 7 to another surface region located on the opposite side of that surface.

[0022] The insert 1A according to the first embodiment has a flow path 22 extending from the first surface 3 toward the second surface 5. The flow path 22 is a passage provided inside the insert 1 for supplying coolant to the cutting edge 13 during cutting. There are no particular limitations on the method for forming the flow path 22. For example, the flow path 22 may be formed in the insert 1 by drilling, laser processing, manufacturing using a 3D printer, or the like.

[0023] In a non-limiting example shown in Fig. 4, the flow path 22 has an outlet 23 that opens in the first surface 3. The outlet 23 is configured to discharge the coolant that has flowed through the flow path 22. In the non-limiting example shown in Fig. 4, the outlet 23 is elliptical when viewed from above. More specifically, when viewed from above, the ellipse has a longer length in the direction in which the first flow path 25 extends, i.e., a vertically elongated ellipse. The shape of the outlet 23 is not limited to the above and may be, for example, a circle, a horizontally elongated ellipse, or a substantially triangular shape.

[0024] In the insert 1A according to the first embodiment, as shown in a non-limiting example in FIG. 5 , the flow path 22 has a first flow path 25 extending from the outlet 23 toward the second surface 5. Furthermore, as shown in a non-limiting example in FIG. 7 , in a cross section (hereinafter referred to as the first cross section) that passes through the central axis (hereinafter referred to as the first central axis N1) of the first flow path 25 and is perpendicular to the first surface 3, the width of the first flow path 25 in a direction parallel to the first surface 3 increases with increasing distance from the first surface 3. Specifically, in the non-limiting example shown in FIG. 7 , the width W1 of the first flow path 25 in a direction parallel to the first surface 3 increases with increasing distance from the first surface 3. This is also true for the configuration shown in FIG.

[0025] FIG. 5 is a V-V cross section of the insert 1 taken along line V-V shown in FIG. 4. The V-V cross section includes the first central axis N1 and is perpendicular to the first surface 3. The first cross section (V-V cross section) may include the central axis O of the insert 1. In the non-limiting example shown in FIG. 4, line V-V coincides with the bisector of the first corner 9A. Therefore, the first cross section (V-V cross section) may be a cross section taken along the bisector of the first corner 9A. FIG. 6 is a diagram showing a modified example of the first flow passage 25 in the insert 1A according to the first embodiment, and corresponds to FIG. 5.

[0026] Furthermore, in the first cross section, if most of the first surface 3 is not linear and the direction parallel to the first surface 3 cannot be uniquely determined, the direction parallel to the first surface 3 may be a direction perpendicular to the central axis O of the insert 1 that passes through the center of the first surface 3 and the center of the second surface 5. Furthermore, in the insert 1A according to the first embodiment, the first flow path 25 is formed by laser processing.

[0027] In the prior art, in order to efficiently supply coolant to the cutting edge, efforts have been made to shorten the distance between the cutting edge and the outlet by providing a flow path inside the insert, etc. However, even with these efforts, there is a limit to how much the coolant flow rate (injection pressure) can be increased, and there is a risk that the coolant may not be supplied sufficiently to the cutting edge.

[0028] In the insert 1A according to the first embodiment, the width of the first flow passage 25 in the first cross section in a direction parallel to the first surface 3 increases with increasing distance from the first surface 3. That is, because the first flow passage 25 has an inverse tapered shape, the coolant flow rate (spray pressure) is increased without being restricted by the insert shape, and the coolant can be efficiently supplied to the cutting edge 13. Therefore, with the insert 1A according to the first embodiment, the coolant can be efficiently supplied to the cutting edge 13.

[0029] In the insert 1A according to the first embodiment, the first flow passage 25 in a cross section parallel to the first surface 3 is elliptical, but is not limited to this and may be circular or approximately triangular, for example. In the insert 1A according to the first embodiment, the first flow passage 25 in a cross section perpendicular to the first central axis N1 is circular, but is not limited to this and may be elliptical or approximately triangular, for example.

[0030] In the insert 1A according to the first embodiment, the first center axis N1 approaches the third surface 7 as it approaches the outlet 23. In such a case, the coolant that has flowed through the flow path 22 can be more efficiently discharged in the direction of the cutting edge 13. Specifically, in the first cross section as shown in a non-limiting example in Fig. 5 , the first center axis N1 approaches the third surface 7 as it approaches the outlet 23. In the non-limiting example shown in Fig. 5 , the first center axis N1 extends toward the upper left from the inside of the flow path 22 so as to approach the third surface 7 shown on the left side of the figure as it approaches the outlet 23.

[0031] 5, the first center axis N1 has a linear shape and approaches the third surface 7 as it approaches the outflow port 23. Alternatively, it may be said that the first center axis N1 approaches the third surface 7 as it approaches the first surface 3. More specifically, as in the non-limiting example shown in FIG. 5, the first center axis N1 approaches the cutting edge 13 as it approaches the outflow port 23. Furthermore, the first center axis N1 approaches the first corner 9A as it approaches the outflow port 23.

[0032] In a non-limiting example shown in Fig. 5 , the first flow path 25 has a first flow path wall 29 located near the third surface 7 and a second flow path wall 31 facing the first flow path wall 29. The first flow path 25 may be formed only by the first flow path wall 29 and the second flow path wall 31. Furthermore, as in the non-limiting example shown in Fig. 5 , the first flow path wall 29 and the second flow path wall 31 have a linear shape in the first cross section, but are not limited to this and may have a curved shape, for example.

[0033] 7, the angle between the first flow path wall 29 and the first surface 3 is larger than the angle between the second flow path wall 31 and the first surface 3. Specifically, as in the non-limiting example shown in Fig. 7, in the first cross section, when a line parallel to the first flow path wall 29 is defined as a first imaginary line S1, a line parallel to the second flow path wall 31 is defined as a second imaginary line S2, a line parallel to the first surface 3 is defined as an imaginary extension line T, an angle between the first imaginary line S1 and the imaginary extension line T is defined as a first angle θ1, and an angle between the second imaginary line S2 and the imaginary extension line T is defined as a second angle θ2, θ1 > θ2.

[0034] In addition, when the first flow path wall 29 has a curved shape, the first imaginary line S1 may be a line passing through an end point of the first flow path wall 29 located on the first surface 3 side and an end point of the first flow path wall 29 located on the second surface 5 side. The second imaginary line S2 may be similarly defined when the second flow path wall 31 has a curved shape. Furthermore, when the entire first surface 3 is not linear in the first cross section, the imaginary extension line T may be a line passing through the center of the first surface 3 and the center of the second surface 5 and perpendicular to the central axis O of the insert 1. The first angle θ1 is the angle between the first imaginary line S1 and the imaginary extension line T that is relatively far from the third surface 7. The second angle θ2 is the angle between the second imaginary line S2 and the imaginary extension line T that is relatively far from the third surface 7. The first angle θ1 and the second angle θ2 may each be an acute angle.

[0035] In the above case, the coolant that has flowed through the flow passage 22 can be more efficiently discharged in the direction of the cutting edge 13. Furthermore, as shown in the non-limiting example of FIGS. 5 and 7 , in the first cross section, the second flow passage wall 31 is longer than the first flow passage wall 29. Specifically, when the length of the first flow passage wall 29 is L1 and the length of the second flow passage wall 31 is L2, L2 > L1. In such a case, the coolant that has flowed through the flow passage 22 can also be more efficiently discharged in the direction of the cutting edge 13.

[0036] In the insert 1A according to the first embodiment, in the first cross section, the first flow path wall 29 and the second flow path wall 31 each approach the third surface 7 as they approach the outlet 23. In such a case, the coolant that has flowed through the flow path 22 can be more efficiently discharged toward the cutting edge 13. In a non-limiting example shown in Fig. 5, the entire first flow path wall 29 and the entire second flow path wall 31 each approach the third surface 7 as they approach the outlet 23.

[0037] 5, at least a portion of the first flow passage 25 is located closer to the second surface 5 than the land surface 19. Specifically, as in the non-limiting example shown in FIG. 5, a portion of the first flow passage 25 is located closer to the second surface 5 than an imaginary extension line T' that passes through an end point of the land surface 19 that is located closer to the second surface 5 and is a straight line parallel to the first surface 3. In such a case, the length of the first flow passage 25 is ensured, so that the coolant that has flowed through the flow passage 22 can be more efficiently discharged in the direction of the cutting edge 13.

[0038] In the insert 1A according to the first embodiment, the flow path 22 further includes a second flow path 27 extending from the first flow path 25 toward the second surface 5. In the insert 1A according to the first embodiment, in a cross section (hereinafter referred to as a second cross section) that passes through the central axis (hereinafter referred to as the second central axis N2) of the second flow path 27 and is perpendicular to the first surface 3, the width of the second flow path 27 in the direction perpendicular to the second central axis N2 is constant.

[0039] 5 and 7 , the width W2 of the second flow path 27 in the direction perpendicular to the second central axis N2 is constant from the first surface 3 side toward the second surface 5 side. Note that "constant" does not necessarily mean strictly the same thing, and for example, if the maximum and minimum values ​​of the width W2 of the second flow path 27 are within ±5% of the average value of the width W2 of the second flow path 27, the width W2 of the second flow path 27 may be evaluated as being constant.

[0040] 5 is a V-V cross section of the insert 1 taken along line V-V shown in Fig. 4. The V-V cross section includes the second central axis N2 and is perpendicular to the first surface 3. The second cross section (V-V cross section) may include the central axis O of the insert 1.

[0041] In the insert 1A according to the first embodiment, the first central axis N1 and the second central axis N2 are located on the same cross section, and therefore the cross section in Fig. 5 is both the first cross section and the second cross section. However, this is not limited to this case, and the first cross section and the second cross section may be located on different planes. In the insert 1A according to the first embodiment, the second flow passage 27 is formed by drilling.

[0042] Furthermore, the shape of the second flow passage 27 in a cross section perpendicular to the second center axis N2 is not particularly limited, but in the insert 1A according to the first embodiment, it is circular. Furthermore, in the insert 1A according to the first embodiment, the second flow passage 27 is connected to the first flow passage 25. Specifically, in a non-limiting example shown in Fig. 5, the end of the second flow passage 27 on the side of the first surface 3 is connected to the end of the first flow passage 25 on the side of the second surface 5.

[0043] At the end, the inner diameter of the first flow path 25 and the inner diameter of the second flow path 27 are the same, or the inner diameter of the first flow path 25 is smaller than the inner diameter of the second flow path 27. In such a case, the risk of fluid pressure loss is reduced, and the coolant supply efficiency is likely to be improved.

[0044] In a non-limiting example shown in Figure 5, the second flow path 27 has a third flow path wall 33 located near the third surface 7 and a fourth flow path wall 35 facing the third flow path wall 33. The second flow path 27 may be formed by the third flow path wall 33 and the fourth flow path wall 35. In addition, as in the non-limiting example shown in Figure 5, the third flow path wall 33 and the fourth flow path wall 35 have a linear shape in the second cross section, but are not limited to this and may have a curved shape, for example. In the non-limiting example shown in Figure 5, the third flow path wall 33 is connected to the first flow path wall 29, and the fourth flow path wall 35 is connected to the second flow path wall 31.

[0045] 7 , in the second cross section, the second flow path wall 31 has a first recess 37 at a portion connected to the second flow path 27. In other words, the first recess 37 is located at the end of the second flow path wall 31 on the side of the second surface 5, and is connected to the fourth flow path wall 35. The end of the second flow path wall 31 on the side of the second surface 5 is easily subjected to impact from the coolant flowing through the second flow path 27. Therefore, by providing the first recess 37 in the second flow path wall 31, it is possible to mitigate the impact and increase the durability of the first flow path 25.

[0046] 7 , in the first cross section, the fourth flow path wall 35 has a second recess 39 at a portion connected to the first flow path 25. In other words, the second recess 39 is located at the end of the fourth flow path wall 35 on the side of the first surface 3 and is connected to the second flow path wall 31. The coolant flowing through the second flow path 27 collides with the end of the second flow path wall 31 on the side of the second surface 5, and tends to flow backward relative to the direction of the coolant flow. Therefore, by providing the second recess 39 in the fourth flow path wall 35, the backflowing coolant can be received by the second recess 39, thereby preventing the coolant from flowing backward excessively.

[0047] In addition, in the non-limiting example shown in Figure 7, the first recess 37 and the second recess 39 are each V-shaped, but this is not limited to this and may be, for example, U-shaped with a concave curved portion at the bottom.

[0048] Note that when the second flow path wall 31 and the fourth flow path wall 35 have the first recess 37 and the second recess 39, respectively, the second flow path wall 31 and the fourth flow path wall 35 are not strictly linear in the first cross section and the second cross section. However, because the first recess 37 and the second recess 39 are small relative to the entire flow path 22, even in the above case, the second flow path wall 31 and the fourth flow path wall 35 are evaluated as having a linear shape. Specifically, the shapes of the second flow path wall 31 and the fourth flow path wall 35 when the first recess 37 and the second recess 39 do not exist are defined as the shapes of the second flow path wall 31 and the fourth flow path wall 35, respectively.

[0049] In the insert 1A according to the first embodiment, the shape of the first flow passage 25 in a cross section (hereinafter referred to as a third cross section) perpendicular to the first surface 3 and the first cross section is circular. Specifically, as shown in a non-limiting example in Figures 8 and 9, when, of any two third cross sections, the cross section where the first flow passage 25 is located on the first surface 3 side is defined as a VII-VII cross section and the cross section where the first flow passage 25 is located on the second surface 5 side is defined as a VIII-VIII cross section, the shape of the first flow passage 25 in both cross sections is circular.

[0050] In the insert 1A according to the first embodiment, the VII-VII cross section and the VIII-VIII cross section are cross sections cut along the lines VII-VII and VIII-VIII shown in FIGS. 4 and 5, respectively.

[0051] Here, in the VII-VII cross section, the first flow path 25 is connected to the first surface 3, and therefore the shape of the first flow path 25 is the shape of a first imaginary circle Q1 centered at the first point P1 shown in Fig. 8. In addition, in the VIII-VIII cross section, the first flow path 25 is connected to the second flow path 27, and therefore the shape of the first flow path 25 is the shape of a second imaginary circle Q2 centered at the second point P2 shown in Fig. 9. In addition, the first central axis N1 passes through the first point P1 and the second point P2, and therefore the first point P1 and the second point P2 may be part of the first central axis N1.

[0052] In the insert 1A according to the first embodiment, the inner diameter of the first flow passage 25 in the third cross section gradually increases as the first flow passage 25 moves away from the first surface 3. Specifically, as shown in a non-limiting example in Figures 8 and 9, when the inner diameter of the first imaginary circle Q1 is R1 and the inner diameter of the second imaginary circle Q2 is R2, R2 > R1. In such a case, the coolant supply efficiency is likely to be improved.

[0053] The insert 1B according to the second embodiment is similar to the insert 1A according to the first embodiment except for the details described below (details related to the flow path 22), and therefore the description of the first embodiment will be used for the details other than those described below, and detailed description thereof will be omitted. Figures 10 to 14 showing the insert 1B according to the second embodiment correspond to Figures 3 to 5, 8, and 9 showing the insert 1A according to the first embodiment, respectively.

[0054] In the insert 1B according to the second embodiment, the shape of the first flow passage 25 in the third cross section is elliptical. Specifically, as shown in a non-limiting example in Figures 13 and 14, when, of any two third cross sections, the cross section where the first flow passage 25 is located on the first surface 3 side is taken as the XII-XII cross section and the cross section where the first flow passage 25 is located on the second surface 5 side is taken as the XIII-XIII cross section, the shape of the first flow passage 25 in both cross sections is elliptical.

[0055] In the insert 1B according to the second embodiment, the XII-XII cross section and the XIII-XIII cross section are cross sections cut along the lines XII-XII and XIII-XIII shown in FIGS. 11 and 12, respectively.

[0056] In the XII-XII cross section, the first flow path 25 is connected to the first surface 3, and therefore the shape of the first flow path 25 is a third imaginary ellipse Q3 centered at the third point P3 shown in Fig. 13. In the XIII-XIII cross section, the first flow path 25 is connected to the second flow path 27, and therefore the shape of the first flow path 25 is a fourth imaginary ellipse Q4 centered at the fourth point P4 shown in Fig. 14. In addition, since the first central axis N1 passes through the third point P3 and the fourth point P4, the third point P3 and the fourth point P4 may be part of the first central axis N1.

[0057] Furthermore, in the insert 1B according to the second embodiment, the horizontal width of the first flow passage 25 in the third cross section is greater than the vertical width of the first flow passage 25. Here, the horizontal width refers to the width in a direction parallel to the first surface 3, and the vertical width refers to the width in a direction perpendicular to the first surface 3. Hereinafter, unless otherwise specified, the horizontal width refers to the horizontal width of the first flow passage 25 in the third cross section, and the vertical width refers to the vertical width of the first flow passage 25 in the third cross section.

[0058] 13 and 14, the width W31 of the third imaginary ellipse Q3 is larger than the length W32 of the third imaginary ellipse Q3, and the width W41 of the fourth imaginary ellipse Q4 is larger than the length W42 of the fourth imaginary ellipse Q4. In this case, the coolant can be discharged over a wide range, which tends to improve the supply efficiency of the coolant.

[0059] In addition, in the third cross section, if the majority of the first surface 3 is not linear and the direction parallel to the first surface 3 and the direction perpendicular to the first surface 3 cannot be uniquely determined, the direction parallel to the first surface 3 may be defined as the direction perpendicular to the central axis O of the insert 1, and the direction perpendicular to the first surface 3 may be defined as the direction parallel to the central axis O of the insert 1.

[0060] In the insert 1B according to the second embodiment, the vertical width of the first flow passage 25 gradually increases as the passage 25 moves away from the first surface 3. Specifically, as shown in a non-limiting example in Figures 13 and 14, the vertical width W42 of the fourth imaginary ellipse Q4 is greater than the vertical width W32 of the third imaginary ellipse Q3. In such a case, the second angle θ2 tends to be small, and the coolant supply efficiency tends to improve.

[0061] In the insert 1B according to the second embodiment, the ratio of the vertical width to the horizontal width gradually increases as the first flow passage 25 moves away from the first surface 3. Specifically, in the non-limiting example shown in Figures 13 and 14, W42 / W41 > W32 / W31. In such a case, the coolant supply efficiency is likely to be improved.

[0062] In the insert 1B according to the second embodiment, the lateral width is constant. Specifically, in the non-limiting example shown in Fig. 13 and Fig. 14, W31 = W41. Note that "constant" does not necessarily mean that they are the same in strict terms. For example, the lateral width may be evaluated as being constant if the maximum and minimum values ​​of the lateral width are within ±5% of the average value of the lateral width.

[0063] In the insert 1B according to the second embodiment, the outlet 23 has a substantially triangular shape when viewed from above. Specifically, in the non-limiting example shown in Figures 11 and 12, the width of the outlet 23 in the direction perpendicular to the first central axis N1 increases toward the third surface 7. In the insert 1B according to the second embodiment, the horizontal width of the first flow path 25 in the third cross section is greater than its vertical width, and therefore, in the non-limiting example shown in Figure 11, the apex angle located near the central axis of the insert 1 is greater than 60°.

[0064] Examples of materials for the insert 1 include cemented carbide, cermet, ceramics, cBN (cubic boron nitride), and PCD (polycrystalline diamond).

[0065] Examples of cemented carbide compositions include WC (tungsten carbide)-Co, WC-TiC (titanium carbide)-Co, and WC-TiC-TaC (tantalum carbide)-Co. Here, WC, TiC, and TaC are hard particles, and Co is a binder phase. Cermets are sintered composite materials in which a ceramic component is combined with a metal. Specifically, cermets include compounds whose main component is TiC or TiN (titanium nitride). However, the material of the insert 1 is not limited to these.

[0066] Furthermore, the insert 1 may be made up of only one member made of the material exemplified above, or may be made up of multiple members made of the material exemplified above.

[0067] As shown in FIG. 1 as a non-limiting example, the insert 1 according to this embodiment is configured with a base 41 and a cutting portion 43, and has a polygonal plate shape as a whole. The base 41 has a roughly polygonal plate shape with notches at some of the corners. The cutting portion 43 is bonded to this notched portion using a brazing material or the like. Bonding the cutting portion 43 to the base 41 can also be said to be attached to the base 41. Note that when the insert 1 is configured with only one member as described above, the entire insert 1 may be the cutting portion 43.

[0068] 3 and 5 , the cutting portion 43 includes a portion of the first surface 3, a portion of the third surface 7, the first corner 9A, a portion of the first edge 11A, a portion of the second edge 11B, the cutting edge 13, the land surface 19, and the flow path 22. With respect to the flow path 22, the outlet 23 and the first flow path 25 may be located in the cutting portion 43, and the second flow path 27 may be located in the base 41. The cutting portion 43 also includes a second surface 5 located on the opposite side of the first surface 3. When the entire insert 1 is used as the cutting portion 43, the cutting portion 43 includes a second surface 5.

[0069] When the cutting portion 43 is made of a material with a relatively high hardness, such as cBN or PCD, and the base 41 is made of a material such as cemented carbide, cermet, or ceramics, the insert 1 can be manufactured inexpensively and has high durability against cutting loads. For example, the base 41 may be made of cemented carbide, and the cutting portion 43 may be made of cBN or PCD. The hardness of the base 41 and the cutting portion 43 can be evaluated by measuring the Vickers hardness of each portion.

[0070] When the cutting portion 43 is made of a material with a relatively high hardness, such as cBN or PCD, as in the insert 1 according to this embodiment, it is difficult to perform fine machining on the shape of the cutting portion 43, making it difficult to ensure efficient coolant supply. However, the insert 1 according to this embodiment has an inverse tapered first flow passage 25, which allows coolant to be supplied to the cutting edge 13 more efficiently without being restricted by the shape of the insert 1. Therefore, when the cutting portion 43 is made of the above-mentioned material, the advantage of making the first flow passage 25 in the cutting portion 43 in an inverse tapered shape is more effectively utilized.

[0071] The insert 1 may be configured only by the base portion 41 and the cutting portion 43, but as an example of a configuration other than the above, the insert 1 may be provided with a coating layer (not shown) that covers the surface of the insert 1. The coating layer may cover the entire surface of the insert 1, or may cover only a portion of the surface of the insert 1.

[0072] Examples of materials for the coating layer include aluminum oxide (alumina), and titanium carbides, nitrides, oxides, carbonates, oxynitrides, carbonitrides, and oxycarbonitrides. The coating layer may contain only one of the above materials, or may contain a plurality of materials.

[0073] The coating layer may be formed of only one layer or may be formed of a plurality of layers. However, the material of the coating layer is not limited to these. The coating layer can be formed on the surface of the insert 1 by, for example, chemical vapor deposition (CVD) or physical vapor deposition (PVD).

[0074] 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.

[0075] <Cutting Tool> Next, a cutting tool 101 according to one non-limiting embodiment of the present disclosure will be described with reference to the drawings.

[0076] 15 , the cutting tool 101 of this embodiment includes a holder 105 having a pocket 103 located on the tip side, and the insert 1 according to this embodiment located inside the pocket 103. In the cutting tool 101 of this embodiment, the insert 1 is attached so that at least a part of the cutting edge 13 protrudes from the tip of the holder 105.

[0077] The holder 105 has a long, thin rod shape. A pocket 103 is provided on the tip side of the holder 105. The pocket 103 is a portion into which the insert 1 is attached, and is open to the tip surface of the holder 105. Since the pocket 103 is also open to the side surface of the holder 105, the insert 1 can be easily attached. Specifically, the pocket 103 has a seating surface parallel to the bottom surface of the holder 105 and a restraining side surface inclined relative to the seating surface.

[0078] The insert 1 is positioned in the pocket 103. At this time, the lower surface of the insert 1 may be in direct contact with the pocket 103, or a sheet may be sandwiched between the insert 1 and the pocket 103.

[0079] The insert 1 is attached so that the cutting edge 13 protrudes outward from the holder 105. In this embodiment, the insert 1 is attached to the holder 105 by a clamp member 107. That is, the head of the clamp member 107 is pressed against the inner wall of the through hole 21 of the insert 1, thereby restraining the insert 1 in the pocket 103.

[0080] Examples of materials for the holder 105 include steel and cast iron. When the holder 105 is made of steel, the holder 105 has high toughness.

[0081] In this embodiment, a cutting tool used for so-called turning is exemplified. Examples of turning include internal diameter machining, external diameter machining, and grooving. The cutting tool is not limited to that used for turning. For example, the insert 1 according to the above embodiment may be used in a cutting tool used for milling.

[0082] <Method for Manufacturing Machined Product> Next, a method for manufacturing a machined product according to one non-limiting embodiment of the present disclosure will be described with reference to the drawings.

[0083] The machined product is produced by cutting a workpiece 201. The manufacturing method of the machined product in this embodiment includes 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 201, and (3) a step of separating the cutting tool 101 from the workpiece 201.

[0084] More specifically, first, as shown in a non-limiting example in Fig. 16 , the workpiece 201 is rotated around the axis Z, and the cutting tool 101 is brought relatively close to the workpiece 201. Next, as shown in a non-limiting example in Fig. 17 , the cutting edge 13 of the cutting tool 101 is brought into contact with the workpiece 201 to cut the workpiece 201. Then, as shown in a non-limiting example in Fig. 18 , the cutting tool 101 is moved relatively away from the workpiece 201.

[0085] In this embodiment, the cutting tool 101 is moved in the Y1 direction while the workpiece 201 is being rotated with the axis Z fixed, to bring it closer to the workpiece 201. Also, in Fig. 17, the cutting blade 13 is brought into contact with the rotating workpiece 201 and moved in the Y2 direction to cut the workpiece 201. Also, in Fig. 18, the cutting tool 101 is moved in the Y3 direction while the workpiece 201 is being rotated to move it away from the workpiece 201.

[0086] In the cutting process in the manufacturing method of this 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.

[0087] 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. To continue the cutting process, the workpiece 201 may be kept rotating, and the step of bringing the cutting edge 13 of the insert 1 into contact with different locations on the workpiece 201 may be repeated.

[0088] Examples of materials for the workpiece 201 include carbon steel, alloy steel, stainless steel, cast iron, and non-ferrous metals.

[0089] In one embodiment, [1] the cutting insert has a cutting portion having a first surface having a rake face region, a second surface located opposite the first surface, a third surface located between the first surface and the second surface and having a clearance face region, and a flow path extending from the first surface toward the second surface, the flow path having an outlet opening in the first surface and a first flow path extending from the outlet toward the second surface, and in a first cross section passing through a central axis of the first flow path and perpendicular to the first surface, the width of the first flow path in a direction parallel to the first surface increases with increasing distance from the first surface.

[0090] [2] In the cutting insert according to the above [1], the central axis may approach the third surface as it approaches the outlet.

[0091] [3] In the cutting insert of [1] or [2] above, the first flow path may have a first flow path wall located near the third surface and a second flow path wall facing the first flow path wall, and in the first cross section, the angle formed by the first flow path wall and the first surface may be larger than the angle formed by the second flow path wall and the first surface.

[0092] [4] In the cutting insert according to [3] above, in the first cross section, the first flow path wall and the second flow path wall may each approach the third surface as they approach the outlet.

[0093] [5] In any of the cutting inserts [1] to [4] above, the cutting portion may further have a land surface located between the first surface and the third surface, and at least a portion of the first flow path may be located closer to the second surface than the land surface.

[0094] [6] In any of the cutting inserts [1] to [5] above, the flow path may further have a second flow path extending from the first flow path toward the second surface, and in a second cross section passing through the central axis of the second flow path and perpendicular to the first surface, the width of the second flow path in a direction parallel to the first surface may be constant from the side of the first surface toward the side of the second surface.

[0095] [7] In the cutting insert of [6] above, the first flow path may have a first flow path wall located near the third surface and a second flow path wall opposite the first flow path wall, and in the second cross section, the second flow path wall may have a first recess in a portion connected to the second flow path.

[0096] [8] In the cutting insert of [6] or [7] above, the first flow path has a first flow path wall located near the third surface and a second flow path wall opposite the first flow path wall, the second flow path has a third flow path wall located near the third surface and a fourth flow path wall opposite the third flow path wall, and in the first cross section, the fourth flow path wall may have a second recess in a portion connected to the second flow path wall.

[0097] [9] In the cutting insert according to any one of the above [1] to [8], the first flow path may have an elliptical shape in a third cross section perpendicular to the first surface and the first cross section.

[0098]

[10] In the cutting insert of [9] above, in the third cross section, a horizontal width of the first flow passage may be larger than a vertical width of the first flow passage.

[0099]

[11] In the cutting insert of

[10] above, the vertical width may gradually increase as the first flow path moves away from the first surface, and the ratio of the vertical width to the horizontal width may gradually increase.

[0100]

[12] The cutting insert according to any one of [1] to

[11] above may further have a base to which the cutting portion is bonded, the base being made of cemented carbide, and the cutting portion being made of cubic boron nitride or polycrystalline diamond.

[0101]

[13] The cutting tool may have a holder having a pocket located on the tip side, and a cutting insert according to any one of [1] to

[12] above located in the pocket.

[0102]

[14] A method for manufacturing a machined product may include the steps of rotating a workpiece, bringing the cutting tool described above in

[13] into contact with the rotating workpiece, and removing the cutting tool from the workpiece.

[0103] The invention according to the present disclosure has been described above based on the drawings and embodiments. However, the invention according to the present disclosure is not limited to the above-described embodiments. In other words, the invention according to the present disclosure can be modified in various ways within the scope of the present disclosure, and embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the invention according to the present disclosure. In other words, it should be noted that a person skilled in the art can easily make various modifications or corrections based on the present disclosure. It should also be noted that these modifications or corrections are included in the scope of the present disclosure.

[0104] DESCRIPTION OF SYMBOLS 1A, 1B... Cutting insert (insert) 3... First surface (upper surface) 5... Second surface (lower surface) 7... Third surface (side surface) 9... Corner 9A... First corner 9B... Second corner 9C... Third corner 11... Side 11A... First side 11B... Second side 13... Cutting edge 13A... First cutting edge 13B... Second cutting edge 13C... First corner cutting edge 15... Rake face region 17... Flank face region 19... Land surface 21... Through hole 22... Flow path 23... Outlet 25... First flow path 27... Second flow path 29... First flow path wall 31... Second flow path wall 33... Third flow path wall 35... Fourth flow path wall 37... First recess 39... Second recess 41... Base 43... Cutting portion 101... Cutting tool 103...Pocket 105...Holder 107...Clamping member 201...Workpiece N1, N2...Central axis W1, W2, W31, W32, W41, W42...Width O...Central axis of insert S1, S2...Imaginary straight line T, T'...Imaginary extension line θ1...First angle θ2...Second angle L1, L2...Length P1 to P4...Center of imaginary circle (imaginary ellipse) Q1 to Q4...Imaginary circle (imaginary ellipse) R1, R2...Inner diameter Z...Axis Y1 to Y3...Movement direction

Claims

1. a first surface having a rake face region; a second surface located opposite the first surface; a third surface located between the first surface and the second surface, the third surface having a clearance region; a cutting portion having a flow path extending from the first surface toward the second surface, The flow path is An outlet opening in the first surface; a first flow path extending from the outlet toward the second surface, In a first cross section passing through a central axis of the first flow path and perpendicular to the first surface, A cutting insert, wherein a width of the first flow passage in a direction parallel to the first surface increases with distance from the first surface.

2. The cutting insert according to claim 1 , wherein the central axis approaches the third surface as the central axis approaches the outlet.

3. The first flow path is a first flow wall located near the third surface; a second flow path wall facing the first flow path wall, The cutting insert according to claim 1 , wherein, in the first cross section, an angle between the first flow passage wall and the first surface is larger than an angle between the second flow passage wall and the first surface.

4. The cutting insert according to claim 3 , wherein in the first cross section, the first flow path wall and the second flow path wall each approach the third surface as they approach the outlet.

5. The cutting portion further has a land surface located between the first surface and the third surface, The cutting insert according to claim 1 , wherein at least a portion of the first flow passage is located on a side of the second surface relative to the land surface.

6. The flow path further includes a second flow path extending from the first flow path toward the second surface, 2. The cutting insert according to claim 1, wherein in a second cross section passing through a central axis of the second flow passage and perpendicular to the first surface, a width of the second flow passage in a direction parallel to the first surface is constant from the first surface side to the second surface side.

7. The first flow path is a first flow wall located near the third surface; a second flow path wall facing the first flow path wall, The cutting insert according to claim 6 , wherein the second passage wall has a first recess at a portion connected to the second passage in the second cross section.

8. The first flow path is a first flow wall located near the third surface; a second flow path wall facing the first flow path wall, The second flow path is a third flow wall located near the third surface; and a fourth flow path wall facing the third flow path wall, The cutting insert according to claim 6 , wherein the fourth flow wall has a second recess at a portion connected to the second flow wall in the first cross section.

9. The cutting insert according to claim 1 , wherein in a third cross section perpendicular to the first surface and the first cross section, the first flow passage has an elliptical shape.

10. The cutting insert according to claim 9 , wherein a lateral width of the first flow passage is greater than a vertical width of the first flow passage in the third cross section.

11. As the first flow path moves away from the first surface, The vertical width gradually increases, The cutting insert according to claim 10 , wherein the ratio of the longitudinal width to the lateral width increases progressively.

12. The cutting portion further includes a base portion to which the cutting portion is joined, The cutting insert according to claim 1 , wherein the base portion is made of cemented carbide and the cutting portion is made of cubic boron nitride or polycrystalline diamond.

13. a holder having a pocket located on the tip side; A cutting insert according to any one of claims 1 to 12, located in the pocket; A cutting tool having

14. Rotating the workpiece; contacting the rotating workpiece with the cutting tool according to claim 13; and removing the cutting tool from the workpiece.