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

Abstract

A cutting insert according to the present invention comprises a tip surface, a first surface, a second surface, a first side surface, a second side surface, and a tip cutting edge. The tip cutting edge has a recessed cutting edge. The recessed cutting edge has a first sloped part, a second sloped part, and a bottom part. The bottom part has a first linear part, a first recessed part, and a second recessed part.

Description

Cutting Insert, Cutting Tool, and Method for Manufacturing a Machined Product Cross - Reference to Related Applications

[0001] This application claims the priority of Japanese Patent Application No. 2025 - 004903 filed on January 14, 2025, and the entire disclosure of the prior application is incorporated herein by reference.

[0002] This disclosure relates to a cutting insert, a cutting tool, and a method for manufacturing a machined product used when machining a workpiece such as metal.

[0003] As a cutting tool used when machining a workpiece such as metal, for example, a cutting insert described in Japanese Patent Application Laid - Open No. 2010 - 99815 (Patent Document 1) is known. In the cutting insert of Patent Document 1, a concave tip cutting edge (front cutting edge) is provided.

[0004] In the cutting insert described in Patent Document 1, a concave portion is provided near the center of the front cutting edge. This concave portion is smooth, and there are few points that become the starting points where the chip is bent. Therefore, the chip is unlikely to become small, and there is a risk that the chip is difficult to be discharged. That is, there is a risk that the chip clogs during cutting.

[0005] A one-sided cutting insert, not limited to this disclosure, has a shape extending from a tip to a rear end and comprises: a tip surface located on the tip side; a first surface extending from the tip surface toward the rear end; a second surface located opposite to the first surface; a first side surface located between the first and second surfaces and extending from the tip surface toward the rear end; a second side surface located opposite to the first side surface; and a tip cutting edge located at the intersection of the tip surface and the first surface. The tip cutting edge has a concave cutting edge recessed from the first surface toward the second surface. The concave cutting edge has a linear first inclined portion located on the side of the first side surface and inclined to approach the second surface as it moves away from the first side surface; a linear second inclined portion located on the side of the second side surface and inclined to approach the second surface as it moves away from the second side surface; and a bottom portion connected to the first and second inclined portions. The bottom portion has a first straight section, a first recess connected to the first inclined section and the first straight section, and a second recess connected to the second inclined section.

[0006] This is a perspective view showing a non-limited one-sided cutting insert in this disclosure. This is a front view of the cutting insert shown in Figure 1, viewed from direction A1. This is a front view of the cutting insert shown in Figure 1, viewed from direction A2. This is an enlarged view of region B1 shown in Figure 3. This is an enlarged view of region B2 in Figure 4. This is an enlarged view of a non-limited one-sided cutting insert in this disclosure, viewed from the same field of view as Figure 4. This is an enlarged view of a non-limited one-sided cutting insert in this disclosure, viewed from the same field of view as Figure 4. This is a front view of the cutting insert shown in Figure 1, viewed from direction A3. This is an enlarged view of region B3 shown in Figure 8. This is a front view of the cutting insert in Figure 1, viewed from direction A4. This is a cross-sectional view taken along the line XI-XI in Figure 8. This is a cross-sectional view taken along the line XII-XII in Figure 8. This is a cross-sectional view taken along the line XIII-XIII in Figure 8. This is a cross-sectional view taken along the line XIV-XIV in Figure 8. This is a cross-sectional view taken along the line XV-XV in Figure 8. This is a perspective view showing a non-limited one-sided cutting tool in this disclosure. This is a front view of the cutting tool shown in Figure 16, viewed from direction C1. Figure 16 is a side view of the cutting tool as seen from the C2 direction. This is a side view of a cutting tool from one perspective not limited in this disclosure. This is a schematic diagram showing one step in the manufacturing method of an example of a machined workpiece not limited in this disclosure. This is a schematic diagram showing one step in the manufacturing method of an example of a machined workpiece not limited in this disclosure. This is a schematic diagram showing one step in the manufacturing method of an example of a machined workpiece not limited in this disclosure. This is a schematic diagram showing one step in the manufacturing method of an example of a machined workpiece not limited in this disclosure. This is a schematic diagram showing one step in the manufacturing method of an example of a machined workpiece not limited in this disclosure.

[0007] <Cutting Insert> A cutting insert 1 of one aspect of the present disclosure, not limited thereto, will be described in detail below with reference to the drawings (hereinafter simply referred to as insert 1). However, for the sake of clarity, the drawings referenced below show only the main components necessary to explain the insert 1 of the embodiment in a simplified manner. Therefore, the insert 1 of the present disclosure may include any components not shown in the drawings referenced. Also, the dimensions of the components in each drawing do not faithfully represent the dimensions of the actual components or the dimensional ratios of each component. This disclosure is not limited to the following embodiments.

[0008] Figure 1 is a schematic perspective view of insert 1 according to an embodiment not limited to the present disclosure. Figure 2 is a front view of the first side surface 15a, which will be described later. Figure 3 is a front view of the tip surface 3, which will be described later. Figure 8 is a front view of the first surface 7, which will be described later. Figure 10 is a front view of the second surface 9, which will be described later.

[0009] As shown in the example (not limited to) in Figure 1, the insert 1 may have a shape that extends from the front end 1a to the rear end 1b. For example, the insert 1 may have a prism shape that extends from the front end 1a to the rear end 1b.

[0010] As shown in the example not limited to Figure 2, the insert 1 may have a front end surface 3 and a rear end surface 5. The front end surface 3 may be located on the side of the front end 1a. That is, the front end surface 3 may be located closest to the front end 1a.

[0011] In the example shown in Figure 2, the insert 1 has a rear end face 5. The rear end face 5 may be located on the side of the rear end 1b. That is, the rear end face 5 may be located closest to the rear end 1b. Also, the rear end face 5 may be located on the opposite side from the front end face 3. In the example shown in Figure 2, the rear end face 5 is a flat surface.

[0012] The insert 1 does not necessarily have a rear end face 5. If the insert 1 does not have a rear end face 5, the rear end 1b may be a point. In other words, the insert 1 may be a polygon with the rear end 1b as one of its vertices.

[0013] As shown in the example (not limited to) in Figures 1 and 2, the insert 1 may have a first surface 7 and a second surface 9. The first surface 7 may extend from the front surface 3 toward the rear end 1b. The second surface 9 may be located opposite to the first surface 7.

[0014] As shown in the example not limited to Figures 1 and 2, the insert 1 may have a first connecting surface 11 and a second connecting surface 13. The first connecting surface 11 may be located between the first surface 7 and the rear end surface 5 and connected to the first surface 7 and the rear end surface 5. The first connecting surface 11 may consist of only one surface or may consist of multiple surfaces. Furthermore, the first connecting surface 11 may be a flat surface or a curved surface.

[0015] As shown in the example not limited to Figure 10, the second connecting surface 13 may be located between the second surface 9 and the tip surface 3, and may connect the second surface 9 and the tip surface 3. The second connecting surface 13 may consist of only one surface or may consist of multiple surfaces. Furthermore, the second connecting surface 13 may be a flat surface or a curved surface.

[0016] The first connecting surface 11 and the second connecting surface 13 may be able to contact the holder. In other words, the first connecting surface 11 and the second connecting surface 13 may be used as restraining surfaces when the insert 1 is mounted on the holder.

[0017] The first connecting surface 11 may have a V-shaped groove extending from the first surface 7 toward the rear end surface 5. The second connecting surface 13 may also have a V-shaped groove extending from the second surface 9 toward the front end surface 3. When the first connecting surface 11 and the second connecting surface 13 each have V-shaped grooves, the insert 1 is more easily and stably mounted in the holder.

[0018] As shown in the example not limited to Figures 1-3, the insert 1 may have a side surface 15. The side surface 15 may be located between the first surface 7 and the second surface 9. The side surface 15 may be connected to the first surface 7 and the second surface 9, or it may be separate. In the example not limited to Figures 1-3, the side surface 15 is connected to the first surface 7 and the second surface 9.

[0019] In one example not limited to the one shown in Figure 3, the insert 1 has a first side surface 15a located on the right side and a second side surface 15b located on the left side when viewed from the front of the tip surface 3. The first side surface 15a is located between the first surface 7 and the second surface 9 and may extend from the tip surface 3 toward the rear end 1b. The second side surface 15b may be located on the opposite side from the first side surface 15a. Note that the positional relationship between the first side surface 15a and the second side surface 15b is not limited to the above and may be reversed left and right.

[0020] As shown in the example not limited to Figures 1-3, the insert 1 may have a corner side surface 17. The corner side surface 17 may be located between the tip surface 3 and the side surface 15. The corner side surface 17 may be connected to the tip surface 3 and the side surface 15. In the example not limited to Figures 1-3, the first corner side surface 17a is located between the tip surface 3 and the first side surface 15a, and the second corner side surface 17b is located between the tip surface 3 and the second side surface 15b.

[0021] As shown in the example (not limited to) in Figures 1-3, the insert 1 may be provided with a cutting edge 19. The cutting edge 19 may be located at the intersection of the tip surface 3 and the first surface 7.

[0022] As shown in the example not limited to Figure 4, the tip cutting edge 19 may have a concave cutting edge 21. The concave cutting edge 21 may be recessed from the first surface 7 toward the second surface 9. That is, the concave cutting edge 21 may have a concave shape that is recessed from the first surface 7 toward the second surface 9. The tip cutting edge 19 may be symmetrical or asymmetrical in a front view of the tip surface 3. In the example not limited to Figure 4, the tip cutting edge 19 has a symmetrical shape.

[0023] When the cutting edge 19 is symmetrical, the chips generated during cutting tend to be less uneven, making it easier to cut stably. Note that "symmetrical" here is not limited to a strict definition. Symmetrical design is acceptable if the error in length or angle between corresponding parts on the left and right sides is within 10%.

[0024] As shown in the example not limited to Figure 4, the concave cutting blade 21 may have an inclined portion 23 and a bottom portion 25. In the drawing, the parts labeled 23a and 23b correspond to the inclined portion 23. The concave cutting blade 21 (inclined portion 23) may have a first inclined portion 23a located on the side of the first side surface 15a and a second inclined portion 23b located on the side of the second side surface 15b.

[0025] As shown in the example not limited to Figure 4, the first inclined portion 23a may be inclined such that it approaches the second surface 9 as it moves away from the first side surface 15a. Furthermore, the first inclined portion 23a may be straight. The first inclined portion 23a may be the straight portion of the concave cutting blade 21 that is closest to the first side surface 15a.

[0026] Here, "straight line" does not necessarily mean a perfectly straight line; it may also refer to a slightly curved concave or convex shape. The same meaning may be used for "straight line" in the following explanations.

[0027] Furthermore, "slightly curved" means that the radius of curvature of the first inclined portion 23a is sufficiently large compared to the length of the first inclined portion 23a, specifically that the radius of curvature of the first inclined portion 23a is 10 times or more the length of the first inclined portion 23a.

[0028] As shown in the example not limited to Figure 4, the second inclined portion 23b may be inclined such that it approaches the second surface 9 as it moves away from the second side surface 15b. Furthermore, the second inclined portion 23b may be straight. The second inclined portion 23b may be the straight portion of the concave cutting blade 21 that is closest to the second side surface 15b.

[0029] As shown in the example not limited to Figure 4, the bottom portion 25 may be connected to the first inclined portion 23a and the second inclined portion 23b. The bottom portion 25 may also have a concave shape overall.

[0030] As shown in the example not limited to Figure 4, the bottom portion 25 may have a straight portion 27 and a recess 29. In the drawing, the parts labeled with reference numeral 27a, etc., correspond to the straight portion 27. Also, the parts labeled with reference numerals 29a and 29b correspond to the recess 29. The straight portion 27 does not have to be a straight line in the strict sense, and may be a slightly curved concave or convex shape. In the following description, the inclined portion 23 and the straight portion 27 may be collectively referred to as the "straight portion".

[0031] As shown in the example not limited to Figure 4, the bottom portion 25 may have a first straight portion 27a, a first recess 29a, and a second recess 29b. The first straight portion 27a may be inclined with respect to the second surface 9, or it may be parallel to it.

[0032] As shown in the example not limited to Figure 4, the first recess 29a and the second recess 29b may be concave shapes that are recessed toward the second surface 9. Note that a concave shape means that the radius of curvature of the recess is less than 10 times the length of the straight line connecting both ends of the recess.

[0033] The first recess 29a and the second recess 29b may have a constant radius of curvature, or their radius of curvature may change. When the radius of curvature changes, there are multiple parts with different radii of curvature between the two straight sections. If each radius of curvature is less than 10 times the length of the straight line connecting the two ends of the straight sections, multiple parts with different radii of curvature may be combined into one first recess 29a or second recess 29b.

[0034] As shown in the example not limited to Figure 4, the first recess 29a may be connected to the first inclined portion 23a and the first straight portion 27a. In other words, the first inclined portion 23a and the first straight portion 27a may be adjacent to each other via the first recess 29a.

[0035] As shown in the example shown in Figure 4, the second recess 29b may be connected to the second inclined portion 23b. In other words, the first recess 29a and the second recess 29b may be located at both ends of the bottom portion 25.

[0036] The first straight section 27a may or may not be connected to the second recess 29b. When the first straight section 27a is connected to the second recess 29b, the recess cutting blade 21 has a first inclined section 23a, a second inclined section 23b, and a first straight section 27a, so there are three straight sections. Furthermore, the first recess 29a and the second recess 29b connect the three straight sections, resulting in a configuration where the straight sections and recesses 29 are positioned alternately.

[0037] The configuration of the bottom portion 25 is not limited to those described above. For example, the first straight portion 27a does not have to be connected to the second recess 29b. If the first straight portion 27a is not connected to the second recess 29b, the configuration between the first straight portion 27a and the second recess 29b is not limited. For example, as shown in the example shown in Figure 4 and the example shown in Figure 7, the bottom portion 25 may have further straight portions in addition to the first straight portion 27a, and may have further recesses in addition to the first recess 29a and the second recess 29b.

[0038] Even if the first straight section 27a and the second recess 29b are not connected, the straight sections and recesses may be arranged alternately. In this case, when viewed from the front of the tip surface 3, the tip cutting edge 19 has an angular shape in which the first inclined section 23a, the second inclined section 23b and the first straight section 27a are like sides and the first recess 29a and the second recess 29b are like corners.

[0039] When the cutting edge 19 has an angular shape, chips are more likely to come into contact with the straight sections, resulting in a higher cutting load. In contrast to the straight sections, chips are less likely to come into contact with the concave sections, resulting in a lower cutting load compared to the straight sections. Therefore, unevenness in the cutting load is likely to occur between the straight sections and the concave sections.

[0040] When unevenness occurs in the cutting load, in the chip, the portion generated at the linear part with a large cutting load is likely to become harder than the portion generated at the recess with a small cutting load. Therefore, in the chip, the portion generated by the linear part is hard and the portion generated by the recess is in a relatively soft state. At this time, starting from the portion generated at the recess, the chip is likely to bend. Therefore, the chip is likely to become small and is likely to be discharged. For the above reasons, when the insert 1 has the above configuration, the chip is likely to be discharged.

[0041] When the tip cutting edge 19 is composed only of curved parts having different radii of curvature from each other, compared with the case where the tip cutting edge 19 has a linear part and a recess 29, the difference in hardness between the chip generated at the linear part and the chip generated at the recess 29 is likely to be large. Therefore, the chip is likely to bend stably at the portion generated at the recess. Further, when the first inclined part 23a and the second inclined part 23b are linear, the force for pushing the chip inward is more likely to act, and the chip is likely to become small.

[0042] In the tip cutting edge 19, the total number of linear parts is not limited. In an example shown in FIG. 4 which is not limited, since there are two inclined parts 23 and two linear parts 27, the total number of linear parts is four. Also, in an example shown in FIG. 6 which is not limited, the total number of linear parts is three, and in an example shown in FIG. 7 which is not limited, the total number of linear parts is five.

[0043] When the tip cutting edge 19 has three or more linear parts, a plurality of recesses serving as starting points for the chip to bend can be secured, and the chip is likely to become small. On the other hand, when the number of linear parts is five or less, the tip cutting edge 19 is likely to have an angular shape, and the chip is likely to become small.

[0044] As in an example shown in FIGS. 1 and 3 which is not limited, the insert 1 may have a corner cutting edge 31 at the intersection of the first surface 7 and the corner side surface 17. The corner cutting edge 31 may be connected to the tip cutting edge 19.

[0045] As in the non-limiting example shown in FIG. 1, the insert 1 may have a first cross-cutting edge 32a at the intersection of the first surface 7 and the first side surface 15a, and a second cross-cutting edge 32b at the intersection of the first surface 7 and the second side surface 15b. The first cross-cutting edge 32a may be located over the entire intersection of the first surface 7 and the first side surface 15a, or may be located only partially. The second cross-cutting edge 32b may be located over the entire intersection of the first surface 7 and the second side surface 15b, or may be located only partially.

[0046] As in the non-limiting example shown in FIG. 4, in the front view of the tip surface 3, the direction from the first side surface 15a toward the second side surface 15b may be defined as the width direction D1. At this time, the width direction D1 may be a direction perpendicular to a second reference line M described later.

[0047] As in the non-limiting examples shown in FIGS. 4 and 5, in the front view of the tip surface 3, the width of the first inclined portion 23a in the width direction D1 may be a first width W1, the width of the first straight portion 27a in the width direction D1 may be a second width W2, and the width of the first recess 29a in the width direction D1 may be a third width W3.

[0048] As in the non-limiting examples shown in FIGS. 4 and 5, in the front view of the tip surface 3, the first width W1 and the second width W2 may be larger than the third width W3. In other words, the width in the width direction D1 of the linear portion may be larger than the width in the width direction D1 of the recess.

[0049] When the insert 1 has the above configuration, since the width of the linear portion is relatively larger than the width of the first recess 29a, the tip cutting edge 19 is likely to have an angular shape. Therefore, the first recess 29a is likely to be a starting point for the chip to bend. As a result, the chip is likely to become smaller and is likely to be discharged from the insert 1.

[0050] A virtual line along the width direction D1 may be used as a reference line L. In the non-limiting example shown in FIG. 5, a reference line L1 is shown as one of the reference lines L near the first inclined portion 23a, and another reference line L2 is shown as another one of the reference lines L near the first straight portion 27a.

[0051] As shown in the example not limited to Figure 5, in a front view of the tip surface 3, the angle between the first inclined portion 23a and the reference line L1 may be the first angle θ1, and the angle between the first straight portion 27a and the reference line L2 may be the second angle θ2. The first angle θ1 may be larger than the second angle θ2. In this case, the first angle θ1 may be about 10 to 20°. The second angle θ2 may be about 2 to 8°.

[0052] When the first angle θ1 is greater than the second angle θ2, the first recess 29a tends to become a starting point for bending the chip. As a result, the chip tends to become smaller and is easily discharged from the insert 1.

[0053] As shown in the example not limited to Figure 4, in a front view of the tip surface 3, the first width W1 may be greater than the second width W2. When the first angle θ1 is greater than the second angle θ2, and the first width W1 is greater than the second width W2, a force is more likely to be applied from the first inclined portion 23a in a direction that pushes the chip inward, making it easier for the chip to become smaller.

[0054] As shown in the example not limited to Figure 4, the first straight section 27a may be inclined to approach the second surface 9 as it moves away from the first recess 29a. In other words, the first straight section 27a may be inclined downwards as it moves away from the first recess 29a.

[0055] As shown in the example not limited to Figure 4, the bottom portion 25 may have a second straight portion 27b and a third recess 29c. The second straight portion 27b may be connected to the second recess 29b. Furthermore, the second straight portion 27b may be inclined to approach the second surface 9 as it moves away from the second recess 29b. In other words, the second straight portion 27b may be inclined downward as it moves away from the second recess 29b.

[0056] As shown in the example not limited to Figure 4, the third recess 29c may be connected to the first straight section 27a and the second straight section 27b. In other words, the first straight section 27a and the second straight section 27b may be adjacent to each other via the third recess 29c. In this case, the first straight section 27a and the second straight section 27b may be positioned symmetrically on either side of the third recess 29c. Furthermore, the radius of curvature of the third recess 29c may be constant or may vary.

[0057] When insert 1 has the above configuration, the cutting edge 19 has four straight sections and three recesses, and the straight sections and recesses are arranged alternately. As a result, the cutting edge 19 tends to have an angular shape, and the chips tend to be small. For these reasons, chips are easily discharged from insert 1.

[0058] As shown in Figure 7, which is an embodiment different from Figure 4, the bottom portion 25 may have a second straight portion 27b, a third straight portion 27c, a fourth recess 29d, and a fifth recess 29e. The fourth recess 29d may be connected to the first straight portion 27a. The fifth recess 29e may be connected to the second straight portion 27b. The radius of curvature of the fourth recess 29d and the fifth recess 29e may be constant or may vary.

[0059] As shown in the example not limited to Figure 7, the third linear portion 27c may be connected to the fourth recess 29d and the fifth recess 29e. The third linear portion 27c may also be a straight section.

[0060] When insert 1 has the above configuration, the cutting edge 19 at the tip tends to have an angular shape, and the chips tend to be smaller. Therefore, chips are easily discharged from insert 1.

[0061] As shown in the example not limited to Figure 5, in a front view of the tip surface 3, the radius of curvature of the first recess 29a may be larger than the radius of curvature of the third recess 29c. When the insert 1 has the above configuration, the chip is more easily bent at the third recess 29c during cutting. In other words, the chip is more easily bent near the middle of the tip cutting edge 19, so the chip tends to become smaller. Therefore, the chip is more easily discharged from the insert 1 and less likely to clog.

[0062] As shown in the example (not limited to) in Figures 8 and 11, the first surface 7 may have a rake face 33. The rake face 33 may be connected to the tip cutting edge 19. Furthermore, the rake face 33 may be inclined to approach the second surface 9 as it moves away from the tip cutting edge 19. Here, moving away from the tip cutting edge 19 may mean moving away from the tip cutting edge 19 in the direction toward the rear end 5b. Figure 11 is a cross-section passing through the midpoint of the tip cutting edge 19 and parallel to the side surface 15.

[0063] As shown in the example not limited to Figure 9, the rake face 33 may have a first rake face 35, a second rake face 37, a first concave face 39, a second concave face 41, and a third concave face 43. The first rake face 35 may be connected to the first inclined portion 23a. The second rake face 37 may be connected to the first straight portion 27a. The first rake face 35 and the second rake face 37 may be flat or curved.

[0064] As shown in the example not limited to Figure 9, the first concave surface 39 may be connected to the first recess 29a. The second concave surface 41 may be connected to the second recess 29b. The third concave surface 43 may be connected to the third recess 29c. Furthermore, the first concave surface 39, the second concave surface 41, and the third concave surface 43 may be recessed toward the second surface 9.

[0065] When insert 1 has the configuration described above, the rake face 33 will have an angular shape, similar to the cutting edge 19, as shown in the example (not limited to) in Figures 12-15. When the rake face 33 has an angular shape, the chip is less likely to come into contact with the first concave surface 39, the second concave surface 41, and the third concave surface 43 of the rake face 33 as it flows along it. The parts of the chip that do not come into contact with the rake face 33 are less likely to undergo work hardening. Therefore, the relatively soft parts that do not come into contact with the rake face 33 tend to become the starting point for the chip to bend and become smaller.

[0066] For the reasons stated above, when insert 1 has the above configuration, the chips tend to be smaller and are easily discharged. Figures 12 to 15 show cross-sections parallel to the rear end surface 5.

[0067] As shown in the example not limited to Figure 9, the rake face 33 may have a third rake face 45 and a fourth rake face 47. The third rake face 45 may be connected to the second inclined portion 23b. The fourth rake face 47 may be connected to the second straight portion 27b.

[0068] As shown in the example (not limited to) in Figures 12-15, a virtual plane parallel to the second surface 9 may be used as the reference plane S. In Figures 12-15, as an example of the reference plane S, reference planes S1-S4 located near the first rake face 35 and reference planes S5-S8 located near the second rake face 37 are shown.

[0069] In the example shown in Figures 12-15, which is not limited to this case, the second surface 9 is a flat surface. In such a case, it is possible to set the reference surface S based on the second surface 9. On the other hand, if the second surface 9 is not flat and it is difficult to set the reference surface S based on the second surface 9, a virtual surface perpendicular to the rear end surface 5 and the first side surface 15a may be set as the reference surface S.

[0070] As shown in the example not limited to Figure 12, in a cross section perpendicular to the reference plane S, the first rake face 35, the second rake face 37, the third rake face 45, and the fourth rake face 47 may be shown as straight lines, while the first concave surface 39, the second concave surface 41, and the third concave surface 43 may be shown as concave curves. When the rake face 33 has the above configuration, the portion of the chip that flows through the first rake face 35, the second rake face 37, the third rake face 45, and the fourth rake face 47 is less likely to bend, while the portion of the chip that flows through the first concave surface 39, the second concave surface 41, and the third concave surface 43 is more likely to bend.

[0071] As shown in the example (not limited to) Figures 8 and 11, the first surface 7 may have a rising surface 49. The rising surface 49 may be located further away from the tip 1a than the scooping surface 33. The rising surface 49 may also be inclined so as it moves away from the scooping surface 33, it moves away from the second surface 9.

[0072] The rising surface 49 may be connected to the scooping surface 33, or it may be separate. If the scooping surface 33 and the rising surface 49 are located separately, a connection part may be located between the scooping surface 33 and the rising surface 49.

[0073] As shown in the example not limited to Figure 9, the third concave surface 43 may have a third pre-concave region 43a. The third pre-concave region 43a may be connected to the third recess 29c. The width of the third pre-concave region 43a in the width direction D1 may increase as it moves away from the third recess 29c.

[0074] The chips become longer as they move away from the cutting edge 19. As a result, the chips become less able to be supported by the rake face 33, and the chips are less likely to flow stably over the rake face 33.

[0075] Therefore, if the width of the third concave region 43a in the width direction D1 increases as it moves away from the third recess 29c, the width of the third concave region 43a also increases as the chip length increases. As a result, the chip is more easily supported stably by the rake face 33, and the cutting becomes more stable.

[0076] For the reasons stated above, if insert 1 has the above configuration, stable cutting is easier.

[0077] As shown in the example not limited to Figure 9, the third concave surface 43 may have a third rear region 43b. The third rear region 43b may be located further away from the third recess 29c than the third front concave region 43a. The third rear concave region 43b may be a region of the third concave surface 43 other than the third front concave region 43a.

[0078] As shown in the example (not limited to) in Figures 12-15, the angle formed by the first rake face 35 and the reference planes S1-S4 may be the third angle θ3. More specifically, the angle formed by the first rake face 35 and the reference planes S1-S4 in a cross section passing through the first rake face 35 and parallel to the rear end face 5 may be the third angle θ3.

[0079] As shown in the example (not limited) in Figures 12 and 13, the third angle θ3 may increase as it moves away from the first inclined portion 23a. Furthermore, as shown in the example (not limited) in Figures 13 and 14, and in Figures 14 and 15, the third angle θ3 may increase as it moves away from the first inclined portion 23a. In other words, the first rake face 35 may have a portion P where the third angle θ3 increases as it moves away from the first inclined portion 23a.

[0080] When insert 1 has the above configuration, the chips generated at the cutting edge 19 are easily bent along the change in the size of the third angle θ3. As a result, the chips tend to become smaller.

[0081] Part P may be connected to the first inclined portion 23a, or it may be separated from the first inclined portion 23a. In the example shown in Figure 9, which is not limited to this example, part P is connected to the first inclined portion 23a.

[0082] When part P is connected to the first inclined portion 23a, the chips are easily bent immediately after they are generated. Therefore, the chips tend to be smaller compared to when part P is not connected to the first inclined portion 23a.

[0083] Furthermore, part P may be located on the entire first rake face 35, or only on a part of it. In the example shown in Figures 9 and 12-15, part P is located on the entire first rake face 35. That is, the entire first rake face 35 is part P.

[0084] When part P is located across the entire first rake face 35, the chips are more susceptible to the influence of the first rake face 35 from the moment they are generated at the first inclined portion 23a until they are discharged. Therefore, the chips tend to be smaller compared to when part P is located only in a portion of the first rake face 35.

[0085] In the example shown in Figures 12-15, the third angle θ3 increases from Figure 12 to 15, so it can be said that the portion P is located across the entire first rake face 35. In this case, the size of the third angle θ3 may be approximately 11-25°.

[0086] As shown in the example not limited to Figure 9, the second rake face 37 may have a second pre-rake region 37a. The second pre-rake region 37a may be connected to the first straight portion 27a. The second pre-rake region 37a may be connected to the third pre-concave region 43a, and there may be a surface between the second pre-rake region 37a and the third pre-concave region 43a for connection with the third pre-concave region 43a.

[0087] As shown in the example (not limited to) in Figures 12 and 13, the angle between the second front scoop region 37a and the reference plane S may be defined as the fourth angle θ4. More specifically, the angle between the second front scoop region 37a and the reference planes S1 to S4 in a cross section passing through the second front scoop region 37a and parallel to the rear end surface 5 may be defined as the fourth angle θ4.

[0088] In the example shown in Figures 12 and 13, the fourth angle θ4 shown in Figure 13 is larger than the fourth angle θ4 shown in Figure 12. In this case, the fourth angle θ4 may increase as it moves away from the first straight section 27a.

[0089] When the insert 1 has the above configuration, the chips generated at the cutting edge 19 are easily bent along the change in the size of the fourth angle θ4. As a result, the chips tend to become smaller. The size of the fourth angle θ4 may be about 2 to 9 degrees.

[0090] As shown in the example not limited to Figure 9, the second rake face 37 may have a second rear rake region 37b. The second rear rake region 37b may be located further away from the first straight section 27a than the second front rake region 37a. The second rear rake region 37b may be connected to a third rear concave region 43b. Also, a surface connecting the second front rake region 37a and the second rear rake region 37b may exist between these regions.

[0091] As shown in the example not limited to Figures 14 and 15, the angle between the second back scoop region 37b and the reference plane S may be defined as the fifth angle θ5. In the example not limited to Figures 14 and 15, the fifth angle θ5 shown in Figure 15 is smaller than the fifth angle θ5 shown in Figure 14. In this case, the fifth angle θ5 may decrease as it moves away from the second front scoop region 37a.

[0092] When insert 1 has the above configuration, just before the chip is discharged from insert 1, the fifth angle θ5 becomes smaller, making it easier for the chip to be supported by the second rake face 37. Therefore, the guiding performance for chip discharge by the second rake face 37 tends to be higher. The size of the fifth angle θ5 may be about 1 to 9°.

[0093] As shown in the example not limited to Figure 9, the width of the second front rake region 37a in the width direction D1 may increase as it moves away from the first straight section 27a. When the fourth angle θ4 increases as it moves away from the first straight section 27a, and the width of the second front rake region 37a in the width direction D1 also increases as it moves away from the first straight section 27a, it is easier to improve the guide performance for chip discharge while ensuring the width of the second front rake region 37a in the width direction D1.

[0094] As shown in the example not limited to Figure 9, the width of the second rear rake region 37b in the width direction D1 may decrease as it moves away from the second front rake region 37a. When the fifth angle θ5 decreases as it moves away from the second front rake region 37a, and the width of the second rear rake region 37b in the width direction D1 also decreases as it moves away from the second front rake region 37a, a force pushing the chip inward from the second rear rake region 37b becomes easier, and the chip tends to become smaller.

[0095] As shown in the example not limited to Figure 4, the tip cutting edge 19 may have a protrusion 51. The protrusion 51 may be located closer to the first side surface 15a than the concave cutting edge 21. In this case, the protrusion 51 may or may not be connected to the first inclined portion 23a. In the example not limited to Figures 4 and 5, the protrusion 51 and the first inclined portion 23a are connected. Also, as shown in the example not limited to Figure 5, the protrusion 51 may project in a direction away from the second surface 9.

[0096] As shown in the example not limited to Figure 9, the rake face 33 may have a convex surface 53. As shown in the example not limited to Figures 12-15, the convex surface 53 may extend from the convex portion 51 toward the rear end 1b. The convex surface 53 may project away from the second surface 9 and away from the first side surface 15a.

[0097] When insert 1 has the above configuration, the convex portion 51 and the convex surface 53 can easily act as guides for chips to flow, allowing the chips to flow stably.

[0098] As shown in the example not limited to Figure 4, the tip cutting edge 19 may have a protrusion 51 located closer to the second side surface 15b than the concave cutting edge 21. In this case, the protrusion 51 located on the side of the first side surface 15a may be called the first protrusion 51a, and the protrusion 51 located on the side of the second side surface 15b may be called the second protrusion 51b.

[0099] As shown in the example (not limited to) in Figures 12-15, the rake face 33 may have a convex surface 53 located closer to the second side surface 15b than the third rake face 45. In this case, the convex surface 53 located on the side of the first side surface 15a may be called the first convex surface 53a, and the convex surface 53 located on the side of the second side surface 15b may be called the second convex surface 53b.

[0100] As shown in the example not limited to Figure 2, the direction perpendicular to the reference plane S may be defined as the height direction D2. The protrusion 51 may be located further away from the second surface 9 than from the first surface 7 in the height direction D2. In other words, the length from the protrusion 51 to the second surface 9 in the height direction D2 may be greater than the length from the first surface 7 to the second surface 9.

[0101] Furthermore, when it is stated that "the protrusion 51 is located further from the second surface 9 than the first surface 7 in a direction perpendicular to the reference surface S," the protrusion 51 may not be included in the first surface 7. In other words, the protrusion 51 may be compared with the portion of the first surface 7 other than the tip cutting edge 19 that intersects with the tip surface 3.

[0102] The portion of the concave cutting blade 21 closest to the second surface 9 may be located at the bottom 25. In the example shown in Figure 4, the portion of the concave cutting blade 21 closest to the second surface 9 is located at the third recess 29c. In the example shown in Figure 6, the portion of the concave cutting blade 21 closest to the second surface 9 is located at the first straight section 27a. In the example shown in Figure 7, the portion of the concave cutting blade 21 closest to the second surface 9 is located at the third straight section 27c.

[0103] As shown in the example shown in Figure 8, the cutting edge 19 may have a concave shape that is recessed from the tip 1a to the rear end 1b in a front view of the first surface 7.

[0104] The insert 1 is not limited to a specific size. For example, the distance between the front end 1a and the rear end 1b when the first surface 7 is viewed from the front may be set to about 5 to 13 mm. Also, the distance between the first side surface 15a and the second side surface 15b when the first surface 7 is viewed from the front may be set to about 1 to 6 mm. The distance between the first surface 7 and the second surface 9 when the first side surface 15a is viewed from the front may be set to about 4 to 15 mm.

[0105] Examples of materials for insert 1 include cemented carbide, cermet, and ceramic inorganic materials. 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 the bonding phase. Cermet is a sintered composite material in which a metal is combined with a ceramic component. Specifically, examples of cermets include compounds mainly composed of TiC or TiN (titanium nitride). However, insert 1 is not limited to these materials.

[0106] Furthermore, the surface of the insert 1 may be coated with a coating layer by chemical vapor deposition (CVD) or physical vapor deposition (PVD). Examples of materials for the coating layer include aluminum oxide (alumina), titanium carbides, nitrides, oxides, carbonites, nitrogen oxides, and carbonitrin oxides. The coating layer may contain only one of the above substances, or it may contain multiple substances. The coating layer may consist of only one layer, or it may consist of multiple layers stacked together. The material of the coating layer is not limited to these.

[0107] <Cutting Tools> Next, cutting tools 101 and 111 of embodiments not limited to the present disclosure will be described.

[0108] The cutting tool 101 is used for milling. Therefore, the cutting tool 101 may also be referred to as the rotary tool 101. As shown in the example (not limited to) in Figures 16-18, the rotary tool 101 may comprise a disc-shaped holder 103 centered on a rotation axis R1 and an insert 1. The holder 103 may have a pocket 105 (insert pocket) located on the outer circumference of the holder 103. The insert 1 may be located in the pocket 105.

[0109] There may be only one pocket 105, or there may be multiple pockets 105. In one example, not limited to those shown in Figures 16-18, the holder 103 has multiple pockets 105. When the holder 103 has multiple pockets 105, the rotary tool 101 may have multiple inserts 1, with one insert positioned in each pocket 105.

[0110] The pocket 105 may open onto the outer circumferential surface of the holder 103. When the holder 103 has a plurality of pockets 105, these pockets 105 may be positioned at equal or unequal intervals around the rotation axis R1.

[0111] The insert 1 may be mounted in the pocket 105 such that at least a portion of it protrudes from the holder 103. Specifically, in one example not limited to those shown in Figures 16 and 17, the cutting edge 19 protrudes from the outer circumference of the holder 103.

[0112] The holder 103 may be made of steel, cast iron, or other materials. In particular, when steel is used among these materials, the toughness of the holder 103 is high.

[0113] As shown in the example (not limited to) in Figures 16 and 17, the second reference line M may be a virtual line passing through the cutting edge 19 and perpendicular to the rotation axis R1. In the above description, the values ​​that were evaluated using the reference line L may be evaluated using the second reference line M. The width direction D1 may be a direction perpendicular to the second reference line M from the first side surface 15a to the second side surface 15b. The height direction D2 may be a direction perpendicular to the width direction D1 and the second reference line M.

[0114] Furthermore, a plane parallel to the second reference line M and the width direction D1 may be designated as the second reference plane T. In the above explanation, the values ​​that were evaluated using the reference plane S may also be evaluated using the second reference plane T.

[0115] The cutting tool 111 is used for turning. Therefore, the cutting tool 111 may also be referred to as the turning tool 111. As shown in the example shown in Figure 19, the turning tool 111 may be a rod-shaped tool extending from a first end 113a to a second end 113b, and may include a holder 113 having a pocket 115 (insert pocket) on the side of the first end 111a, and the above-mentioned insert 1 located in the pocket 115.

[0116] As shown in the example not limited to Figure 19, the pocket 115 is the portion into which the insert 1 is fitted, and in this case, the base portion of the insert 1 (first connecting surface 11 and second connecting surface 13) may be in direct contact with the pocket 115.

[0117] As shown in the example below (not limited to) in Figure 19, the insert 1 may be mounted such that at least a portion of the part used as a cutting edge protrudes outward from the holder 113.

[0118] The holder 113 may be made of steel, cast iron, or other materials. In particular, when steel is used among these materials, the toughness of the holder 113 is high.

[0119] <Method for Manufacturing Machined Workpieces> Next, a method for manufacturing machined workpieces according to an embodiment not limited to the present disclosure will be described.

[0120] A workpiece can be produced by cutting the workpiece 201. The method for manufacturing a workpiece in an embodiment using the rotary tool 101 of the present disclosure may include the following steps: (1) a step of rotating the rotary tool 101; (2) a step of bringing the rotating rotary tool 101 into contact with the workpiece 201; and (3) a step of moving the rotary tool 101 away from the workpiece 201.

[0121] More specifically, as shown in the example (not limited) in Figure 20, the rotary tool 101 may be brought relatively closer to the workpiece 201 while rotating it in the X1 direction around the rotation axis R1. Next, as shown in the example (not limited) in Figure 21, the cutting edge of the rotary tool 101 may be brought into contact with the workpiece 201 to cut the workpiece 201. Then, as shown in the example (not limited) in Figure 22, the rotary tool 101 may be moved relatively further away from the workpiece 201.

[0122] In the example shown in Figure 20, the workpiece 201 is fixed and the rotary tool 101 is rotated in the X1 direction around the rotation axis R1, and the rotary tool 101 is moved in the Y1 direction to bring it closer to the workpiece 201. In the example shown in Figure 22, the workpiece 201 is fixed and the rotary tool 101 is moved away. In the cutting process in the manufacturing method of the embodiment, the workpiece 201 is fixed and the rotary tool 101 is moved in each step, but of course, the method is not limited to these configurations.

[0123] For example, in step (1), the workpiece 201 may be brought closer to the rotating tool 101. Similarly, in step (3), the workpiece 201 may be moved away from the rotating tool 101. If the cutting process is to be continued, the rotating tool 101 may be kept rotating, and the process of bringing the cutting edge of the insert 1 into contact with different parts of the workpiece 201 may be repeated.

[0124] Furthermore, the method for manufacturing a cut workpiece in an embodiment using the turning tool 111 of this disclosure may include the following steps: (1) a step of rotating the workpiece 201; (2) a step of bringing the turning tool 111, as represented in the above embodiment, into contact with the rotating workpiece 201; and (3) a step of moving the turning tool 111 away from the workpiece 201.

[0125] More specifically, first, as shown in the example without limitation in Figure 23, the workpiece 201 may be rotated around the rotation axis R2, and the turning tool 111 may be brought relatively close to the workpiece 201. Next, as shown in the example without limitation in Figure 24, the edge (cutting edge) of the turning tool 111 may be brought into contact with the workpiece 201 to cut the workpiece 201. Then, as shown in the example without limitation in Figure 25, the turning tool 111 may be moved relatively far away from the workpiece 201.

[0126] In one example not limited to Figure 23, the turning tool 111 is moved in the Y2 direction while the rotating axis R2 is fixed and the workpiece 201 is rotated around the rotating axis R2, thereby bringing it closer to the workpiece 201. In another example not limited to Figure 24, the workpiece 201 is cut by bringing the cutting edge of the insert 1 into contact with the rotating workpiece 201. In another example not limited to Figure 25, the turning tool 111 is moved away from the workpiece 201 by moving it in the Y3 direction while the workpiece 201 is rotating.

[0127] In the manufacturing method of this embodiment, the turning tool 111 is moved in each step to bring the turning tool 111 into contact with the workpiece 201 or to move the turning tool 111 away from the workpiece 201, but of course, the method is not limited to this configuration.

[0128] For example, in step (1), the workpiece 201 may be brought closer to the turning tool 111. Similarly, in step (3), the workpiece 201 may be moved away from the turning tool 111. If the cutting process is to be continued, the process of bringing the cutting edge of the insert 1 into contact with different parts of the workpiece 201 while maintaining the rotation of the workpiece 201 may be repeated.

[0129] Examples of materials for the workpiece 201 include carbon steel, alloy steel, stainless steel, cast iron, and non-ferrous metals.

[0130] 1...Cutting insert (insert) 1a...Tip 1b...Rear end 3...Tip surface 5...Rear end surface 7...First surface 9...Second surface 11...First connecting surface 13...Second connecting surface 15...Side surface 15a...First side surface 15b...Second side surface 17...Corner side surface 17a...First corner side surface 17b...Second corner side surface 19...Tip cutting edge 21...Concave cutting edge 23...Inclined section 23a...First inclined section 23b...Second inclined section 25...Bottom section 27...Straight section 27a...First straight section 27b...Second straight section 27c...Third straight section 29...Recess 29a...First recess 29b...Second recess 29c...Third recess 29d...Fourth recess 29e...Fifth recess 31...Corner cutting edge 32a...First cross cutting edge 32b...Second cross cutting edge 33...Rake face 35...First rake face 37...Second rake face 37a...Second front rake area 37b...Second rear rake area 39...First concave face 41...Second concave face 43...Third concave face 43a...Third front concave area 43b...Third rear concave area 45...Third rake face 47...Fourth rake face 49...Rising face 51...Convex part 51a...First convex part 51b...Second convex part 53...Convex face 53a...First convex face 53b...Second convex face 101...Cutting tool (rotary tool) 103...Holder 105...Pocket 111...Cutting tool (turning tool) 113... Holder 113a... First end 113b... Second end 115... Pocket 201... Work material D1... Width direction D2... Height direction L... Reference line M... Second reference line S... Reference surface T... Second reference surface W1... First width W2... Second width W3... Third width θ1... First angle θ2... Second corner θ3...Third angle θ4...Fourth angle θ5...Fifth angle

Claims

1. A shape extending from the tip to the rear end, comprising: a tip surface located on the tip side; a first surface extending from the tip surface toward the rear end; a second surface located opposite to the first surface; a first side surface located between the first surface and the second surface and extending from the tip surface toward the rear end; a second side surface located opposite to the first side surface; and a tip cutting edge located at the intersection of the tip surface and the first surface, wherein the tip cutting edge has a concave cutting edge recessed from the first surface toward the second surface, the concave cutting edge having: a linear first inclined portion located on the side of the first side surface and inclined to approach the second surface as it moves away from the first side surface; a linear second inclined portion located on the side of the second side surface and inclined to approach the second surface as it moves away from the second side surface; and a bottom portion connected to the first inclined portion and the second inclined portion, wherein the bottom portion has: a first straight portion; and a first recess connected to the first inclined portion and the first straight portion, A cutting insert having a second recess connected to the second inclined portion.

2. In a front view of the tip surface, when the direction from the first side surface toward the second side surface is defined as the width direction, the width of the first inclined portion and the width of the first straight portion in the width direction are greater than the width of the first recess in the width direction, as described in claim 1.

3. In a front view of the tip surface, when the direction from the first side surface to the second side surface is defined as the width direction, a virtual line along the width direction is a reference line, and the angle between the first inclined portion and the reference line is greater than the angle between the first straight portion and the reference line, as described in claim 1 or 2.

4. The cutting insert according to claim 3, wherein the width of the first inclined portion in the width direction is greater than the width of the first straight portion in the width direction.

5. The cutting insert according to any one of claims 1 to 4, wherein the bottom portion further comprises a second straight portion connected to the second recess and inclined to approach the second surface as it moves away from the second recess, and a third recess connected to the first straight portion and the second straight portion, the first straight portion inclined to approach the second surface as it moves away from the first recess.

6. The cutting insert according to claim 5, wherein, in a front view of the tip surface, the radius of curvature of the first recess is greater than the radius of curvature of the third recess.

7. The cutting insert according to claim 5 or 6, wherein the first surface has a rake face that is connected to the tip cutting edge and is inclined to approach the second surface as it moves away from the tip cutting edge, and the rake face has a first rake face connected to the first inclined portion, a second rake face connected to the first straight portion, a first concave surface connected to the first recess and recessed toward the second surface, a second concave surface connected to the second recess and recessed toward the second surface, and a third concave surface connected to the third recess and recessed toward the second surface.

8. The cutting insert according to claim 7, wherein the third concave surface has a third concave region connected to the third recess, and when the direction from the first side surface toward the second side surface is defined as the width direction, the width of the third concave region in the width direction increases as it moves away from the third recess.

9. The cutting insert according to claim 7 or 8, wherein, when a virtual plane parallel to the second plane is used as the reference plane, the first rake face has a portion where the angle it makes with the reference plane increases as it moves away from the first inclined portion.

10. The cutting insert according to claim 9, wherein the portion is connected to the first inclined portion.

11. The cutting insert according to claim 10, wherein the entire first rake face is the portion described above.

12. The cutting insert according to any one of claims 7 to 11, wherein, when a virtual plane parallel to the second plane is used as the reference plane, the second rake face has a second pre-rake region connected to the first straight portion, and the angle between the second pre-rake region and the reference plane increases as it moves away from the first straight portion.

13. The cutting insert according to claim 12, wherein the second rake face further has a second post-rake region located further away from the first straight portion than the second pre-rake region, and the angle between the second post-rake region and the reference plane decreases as it moves away from the second pre-rake region.

14. The cutting insert according to any one of claims 7 to 13, wherein the tip cutting edge is located closer to the first side surface than the concave cutting edge and has a convex portion projecting toward the second surface, and the rake face has a convex surface extending from the convex portion toward the rear end.

15. The cutting insert according to claim 14, wherein, when a virtual plane parallel to the second plane is used as a reference plane, the protrusion is located further from the second plane than the first plane in a direction perpendicular to the reference plane.

16. A cutting tool comprising a disc-shaped holder centered on a rotation axis and a cutting insert according to any one of claims 1 to 15, wherein the holder has a pocket located on the outer circumference side of the holder, and the cutting insert is located in the pocket.

17. A method for manufacturing a machined workpiece, comprising the steps of: rotating the cutting tool described in claim 16; bringing the cutting tool into contact with a workpiece; and separating the cutting tool from the workpiece.

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