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

Abstract

A cutting insert according to an unrestricted aspect of the present disclosure comprises: an upper surface in the shape of a polygon with long and short sides; a lower surface located on the opposite side of the upper surface; a side surface located between the upper and lower surfaces; a through hole opening at the center of the upper surface and the center of the lower surface; and a cutting edge located on the short side. The side surface comprises a first side surface located along the long side and convex outward when viewed from above. The first side surface comprises: a first plane that coincides with the central axis of the through hole when viewed from the front and is parallel to the central axis; a second plane that is located closer to the short side than the first plane and is parallel to the central axis; a third plane that is located farther from the short side than the first plane and is parallel to the central axis; and a first inclined surface that is located between the second plane and the upper surface and approaches the central axis as it approaches the long side. The first inclined surface is separated from the first plane.

Description

[0001] Cross-reference to related applications

[0002] This application claims the benefit of Japanese Patent Application No. 2020-054422, filed on March 25, 2020, and the entire disclosure of that prior application is incorporated herein by reference. Technical Field

[0003] The present disclosure generally relates to a cutting insert, a cutting tool, and a method for manufacturing a machined product used in cutting a workpiece, and more specifically to a cutting tool for rotary cutting. Background Art

[0004] As a cutting insert used for cutting a workpiece such as metal, for example, a cutting insert described in Japanese Patent Application Laid-Open No. 2004-314301 (Patent Document 1) is known. The cutting insert described in Patent Document 1 is in the shape of a square plate. The cutting insert described in Patent Document 1 has a cutting edge located at the intersection of the upper surface and the side surface, and fixing holes opened on the upper surface and the lower surface.

[0005] In recent years, miniaturization has been required for cutting inserts. However, when miniaturizing the cutting insert, the wall thickness between the through hole (fixing hole) and the side surface tends to become thinner, and durability may decrease. Therefore, it is required to improve the durability of the cutting insert. Summary of the Invention

[0006] A cutting insert according to an unrestricted aspect of the present disclosure comprises: an upper surface having a polygonal shape with a long side and a short side; a lower surface located on the opposite side of the upper surface; a side surface located between the upper surface and the lower surface; a through hole opening at the center of the upper surface and the center of the lower surface; and a cutting edge located at the short side. The side surface comprises a first side surface located along the long side and convex outward when viewed from above. The first side surface comprises: a first plane that coincides with the central axis of the through hole when viewed from the front and is parallel to the central axis; a second plane that is located closer to the short side than the first plane and is parallel to the central axis; a third plane that is located farther from the short side than the first plane and is parallel to the central axis; and a first inclined surface located between the second plane and the upper surface and approaches the central axis as it approaches the long side. The first inclined surface is separated from the first plane. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 It is a perspective view of a cutting insert showing a non-limiting aspect of the present invention.

[0008] Figure 2 It is a bird's-eye view Figure 1 A top view of the cutting insert is shown.

[0009] Figure 3 It is a bird's-eye view Figure 1 A top view of the cutting insert is shown.

[0010] Figure 4 Observed from the direction of A1 Figure 2 A side view of the cutting insert is shown.

[0011] Figure 5 Observed from the direction of A2 Figure 2 A side view of the cutting insert is shown.

[0012] Figure 6 yes Figure 2 A cross-sectional view of section VI-VI is shown.

[0013] Figure 7 yes Figure 2 A cross-sectional view of section VII-VII is shown.

[0014] Figure 8 yes Figure 2 A cross-sectional view of section VIII-VIII is shown.

[0015] Figure 9 yes Figure 2 A cross-sectional view of section IX-IX is shown.

[0016] Figure 10 is a perspective view of a cutting tool illustrating a non-limiting aspect of the present disclosure.

[0017] Figure 11 Viewed from the first end Figure 10 A top view of the cutting tool is shown.

[0018] Figure 12 Observed from the A3 direction Figure 11 A side view of the cutting tool is shown.

[0019] Figure 13 It will Figure 10 An enlarged view of area B1 is shown.

[0020] Figure 14 This is a schematic diagram showing one step in a method for producing a machined product according to a non-limiting aspect of the present disclosure.

[0021] Figure 15 This is a schematic diagram showing one step in a method for producing a machined product according to a non-limiting aspect of the present disclosure.

[0022] Figure 16This is a schematic diagram showing one step in a method for producing a machined product according to a non-limiting aspect of the present disclosure. DETAILED DESCRIPTION

[0023] <Cutting insert>

[0024] Hereinafter, a cutting insert 1 (hereinafter sometimes referred to as "insert 1") according to an unrestricted aspect of the present disclosure will be described in detail using the accompanying drawings. However, in the figures referenced below, only the main components required to illustrate the embodiment are shown in simplified form for ease of description. Therefore, the insert 1 may include any components not shown in the figures referenced. In addition, the dimensions of the components in the figures do not accurately represent the actual dimensions of the components or the dimensional ratios of the components.

[0025] The blade 1 can also be Figures 1 to 9 As shown in the non-limiting example, the blade 1 has an upper surface 3, a lower surface 5, a side surface 7, a through hole 9, and a cutting edge 11. It should be noted that the upper surface 3 and the lower surface 5 are shown for convenience and do not indicate the direction of up and down. For example, the upper surface 3 does not need to face upward when the blade 1 is in use.

[0026] The upper surface 3 can also be Figure 1 The blade 1 may be polygonal in shape, as in the example not limited thereto. For example, the upper surface 3 may be hexagonal. In addition, the lower surface 5 may be located on the opposite side of the upper surface 3. The lower surface 5 may be polygonal in shape, such as hexagonal, similarly to the upper surface 3. Furthermore, the blade 1 may be in the shape of a polygonal plate.

[0027] It should be noted that the polygonal shape only needs to be substantially polygonal and does not need to be strictly polygonal. For example, the multiple edges of the upper surface 3 may not be strictly straight lines and may be curved when the upper surface 3 is viewed from the front (or top). In addition, the multiple corners of the upper surface 3 may not be strictly angles.

[0028] The plurality of sides of the upper surface 3 may include long sides 13 and short sides 15. That is, the upper surface 3 may have long sides 13 and short sides 15. It should be noted that the lower surface 5 may also have long sides and short sides similarly to the upper surface 3. It should be noted that, when the plurality of sides of the upper surface 3 include two sides of different lengths, the relatively longer of the two sides may be the long side 13, and the relatively shorter side may be the short side 15.

[0029] like Figure 2As shown in the non-limiting example, the angle 17 between the long side 13 and the short side 15 may also be an obtuse angle. In this case, the angle 17 is less likely to be damaged. It should be noted that the angle 17 is not limited to the angle formed by the intersection of the long side 13 and the short side 15 in the strict sense. For example, when viewed from above, the angle 17 may be a convex curve, or a combination of straight lines and curves.

[0030] The side surface 7 may be located between the upper surface 3 and the lower surface 5. The side surface 7 may be as follows Figure 4 The upper surface 3 and the lower surface 5 are connected as in the non-limiting example shown.

[0031] When the blade 1 is fixed to the handle, the through hole 9 can be used to insert a screw, for example. It should be noted that when the blade 1 is fixed to the handle, a clamping member, for example, can be used instead of the screw.

[0032] The through hole 9 can be opened at the center of the upper surface 3 and the center of the lower surface 5. In the case where the upper surface 3 is polygonal, the diagonally opposite corners of the upper surface 3 can be connected by straight lines, and the intersection of these straight lines can be used as the center of the upper surface 3. Similarly, in the case where the lower surface 5 is polygonal, the diagonally opposite corners of the lower surface 5 can be connected by straight lines, and the intersection of these straight lines can be used as the center of the lower surface 5. The part that serves as the starting point of the diagonal line can also be the part where the extension lines of the sides constituting the polygon intersect. It should be noted that, in the case where the lower surface 5 is not polygonal, for example, the center of the lower surface 5 can also be determined based on the position of the center of gravity of the lower surface 5 when the lower surface 5 is viewed from the front (viewed from above).

[0033] The central axis O1 of the through hole 9 can be an imaginary straight line passing through the center of the upper surface 3 and the center of the lower surface 5. It should be noted that the central axis of the blade 1 can be an imaginary straight line passing through the center of the upper surface 3 and the center of the lower surface 5. In other words, the central axis O1 of the through hole 9 can be consistent with the central axis of the blade 1.

[0034] The upper surface 3 may be rotationally symmetrical about the central axis O1 in a plan view, and the lower surface 5 may be rotationally symmetrical about the central axis O1 in a bottom view.

[0035] The blade 1 is not limited to a specific size. For example, the maximum width when viewing the upper surface 3 from above can be set to about 6 to 25 mm. In addition, the height from the upper surface 3 to the lower surface 5 can be set to about 1 to 10 mm. The height from the upper surface 3 to the lower surface 5 can refer to the maximum value of the interval between the upper surface 3 and the lower surface 5 in a direction parallel to the central axis O1. In addition, the height from the upper surface 3 to the lower surface 5 can be translated as the width of the side surface 7 in the direction along the central axis O1.

[0036] The cutting edge 11 may be located on the short side 15. The cutting edge 11 can be used to cut a workpiece when the insert 1 is used to manufacture a workpiece. The cutting edge 11 may be located on the entire short side 15 or only on a portion of the short side 15.

[0037] In the case where the cutting edge 11 is located at the short side 15, one of the upper surface 3 and the side surface 7 may have a rake face region, and the other of the upper surface 3 and the side surface 7 may have a flank face region. Figure 1 As shown in the non-limiting example, the upper surface 3 has a rake face region, and the side surface 7 has a flank face region.

[0038] It should be noted that, in addition to the cutting edge 11, the insert 1 may also have other cutting edges located on the side of the lower surface 5. For example, the lower surface 5 may also have a short side located below the short side 15, and the insert 1 may also have other cutting edges located on the short side of the lower surface 5. In this case, the insert 1 can be double-sided.

[0039] Here, the side surface 7 may have a first side surface 19. The first side surface 19 may be located along the long side 13. In addition, the first side surface 19 may be as follows. Figure 2 As in the non-limiting example shown, the shape is convex outward in a plan view.

[0040] The first side surface 19 may have a first flat surface 21 , a second flat surface 23 , a third flat surface 25 , and a first inclined surface 27 .

[0041] The first plane 21, the second plane 23 and the third plane 25 can be used as surfaces that abut (contact) the handle when the blade 1 is fixed to the handle. Figure 4As shown in the non-limiting example, when viewed from the front (or side), the first plane 21 coincides with the central axis O1. In addition, the first plane 21 may be parallel to the central axis O1. The second plane 23 may be located closer to the short side 15 than the first plane 21. The second plane 23 may also be parallel to the central axis O1. The third plane 25 may be located farther from the short side 15 than the first plane 21. The third plane 25 may be parallel to the central axis O1. Parallelism is not limited to strict parallelism and may also mean that an inclination of about ±5° is allowed.

[0042] The first plane 21, the second plane 23, and the third plane 25 can each be a flat surface. Furthermore, the first plane 21, the second plane 23, and the third plane 25 do not need to be strictly flat surfaces. The first plane 21, the second plane 23, and the third plane 25 can be substantially flat surfaces and can be slightly curved to an extent that is not noticeable when viewing the blade 1 as a whole, or can have minute irregularities. For example, the first plane 21, the second plane 23, and the third plane 25 can have minute irregularities of about several tens of μm.

[0043] The first inclined surface 27 may be located between the second plane 23 and the upper surface 3. Figure 6 As shown in the non-limiting example, the first inclined surface 27 is closer to the central axis O1 as it approaches the long side 13. When evaluating the positional relationship with the central axis O1, the imaginary straight line O1a parallel to the central axis O1 can also be used as a reference. Figure 4 As shown in the non-limiting example, the first plane 21 is separated.

[0044] As described above, when the first side surface 19 is generally convex, and the first, second, and third planes 21, 23, and 25 are parallel to the central axis O1, it is easy to maintain a sufficient wall thickness between the through-hole 9 and the first side surface 19, even if the insert 1 is miniaturized. Furthermore, when the first inclined surface 27 is located between the second plane 23 and the upper surface 3, the first inclined surface 27 is easily located near the cutting edge 11. Furthermore, when the first inclined surface 27 approaches the central axis O1 as it approaches the long side 13, the wall thickness of the ridge 29 where the first inclined surface 27 intersects the upper surface 3 is thicker, thus increasing the strength of the ridge 29. Therefore, even if the ridge 29 contacts the workpiece during production, it is less likely to be damaged. Furthermore, when the first inclined surface 27 is separated from the first plane 21 located adjacent to the through-hole 9, it is easy to maintain a sufficient wall thickness between the through-hole 9 and the first side surface 19, even if the first inclined surface 27 is located on the first side surface 19. Consequently, the insert 1 has high durability.

[0045] It should be noted that the second plane 23 can be connected to the first plane 21, and can also be separated from the first plane 21. The third plane 25 can be connected to the first plane 21, and can also be separated from the first plane 21. The first inclined surface 27 can be connected to the second plane 23, and can also be separated from the second plane 23. The first inclined surface 27 can be connected to the upper surface 3, and can also be separated from the upper surface 3. For example, Figure 4 As shown in the non-limiting example, the second plane 23 and the third plane 25 may be connected to the first plane 21. In addition, the first inclined surface 27 may be connected to the second plane 23 and the upper surface 3, respectively.

[0046] The inclination angle θ1 of the first inclined surface 27 relative to the central axis O1 may be constant or may vary. Figure 6 and Figure 7 As in the non-limiting example shown, when the first inclined surface 27 has a portion where the inclination angle θ1 decreases as it approaches the first flat surface 21, the inclination angle θ1 of the portion of the first inclined surface 27 near the through-hole 9 tends to be relatively small. This makes it easier to ensure the wall thickness between the through-hole 9 and the first side surface 19. Furthermore, in this case, the inclination angle θ1 of the portion of the first inclined surface 27 near the cutting edge 11 tends to be relatively large. Consequently, the portion of the ridgeline 29 near the cutting edge 11 is strong, resulting in increased durability of the insert 1.

[0047] It should be noted that the entire first inclined surface 27 may have an inclination angle θ1 that decreases as it approaches the first plane 21. Furthermore, the inclination angle θ1 is not limited to a specific value. For example, the inclination angle θ1 may be set between 1 and 20 degrees. When evaluating the inclination angle θ1, the imaginary straight line O1a may be used as a reference. This also applies to the inclination angle θ2 described later.

[0048] The width W1 of the first inclined surface 27 along the center axis O1 may be constant or may vary. Figure 4 As in the non-limiting example shown, when the first inclined surface 27 has a portion whose width W1 decreases as it approaches the first flat surface 21, the width W1 of the portion of the first inclined surface 27 near the through-hole 9 tends to be relatively smaller. This makes it easier to ensure a sufficient wall thickness between the through-hole 9 and the first side surface 19. Furthermore, in this case, the width W1 of the portion of the first inclined surface 27 near the cutting edge 11 tends to be relatively larger. Consequently, the portion of the ridgeline 29 near the cutting edge 11 has increased strength. Consequently, the blade 1 has enhanced durability.

[0049] It should be noted that the width W1 may decrease as it approaches the first flat surface 21 over the entire range of the first inclined surface 27. Furthermore, the width W1 is not limited to a specific value. For example, the width W1 may be set to 0.3 to 1 mm. The area of ​​the first inclined surface 27 may also be smaller than the area of ​​the second flat surface 23.

[0050] When the first side surface 19 is viewed from above, the first inclined surface 27 can be located closer to the short side 15 than the through hole 9. In this case, the first inclined surface 27 is easily located near the cutting edge 11. Therefore, the durability of the insert 1 is high. In addition, the above structure can also be evaluated when viewed from above.

[0051] When viewing first side surface 19 from the front, ridge line 29 may have a portion approaching lower surface 5 as it approaches first plane 21. Alternatively, when viewing first side surface 19 from the front, ridge line 29 as a whole may extend so as to approach lower surface 5 as it approaches first plane 21.

[0052] The first side surface 19 may further include a second inclined surface 31. The second inclined surface 31 may be located between the third plane 25 and the lower surface 5. In addition, the second inclined surface 31 may be as follows Figure 9 As shown in the non-limiting example, the second inclined surface 31 is spaced away from the central axis O1 as it approaches the long side 13. Figure 4 As shown in the non-limiting example, the first plane 21 is separated.

[0053] For example, when the lower surface 5 has a short side similar to the upper surface 3, and the insert 1 has a cutting edge located on the short side of the lower surface 5 (hereinafter referred to as the lower cutting edge for convenience), the insert 1 has a high durability. When the lower cutting edge is used for cutting instead of the cutting edge 11, the strength of the ridgeline where the second inclined surface 31 intersects with the lower surface 5 is high. In addition, it is easy to ensure the wall thickness between the through hole 9 and the first side surface 19. Therefore, even when the lower cutting edge is used for cutting, the insert 1 has a high durability.

[0054] It should be noted that the second inclined surface 31 may include a portion where the inclination angle θ2 relative to the central axis O1 decreases as it approaches the first plane 21. Furthermore, the second inclined surface 31 may include a portion where the width W2 along the direction of the central axis O1 decreases as it approaches the first plane 21. The area of ​​the second inclined surface 31 may also be smaller than the area of ​​the third plane 25.

[0055] The second plane 23 may be connected to the lower surface 5, or may be separated from the lower surface 5. Figure 4As shown in the non-limiting example, when the second flat surface 23 is connected to the lower surface 5, the area of ​​the second flat surface 23 can be easily increased. Therefore, the wall thickness between the through-hole 9 and the first side surface 19 can be easily maintained, and the durability of the blade 1 is improved. Furthermore, the blade 1 can be easily and stably fixed to the handle. Therefore, the restraint stability of the blade 1 is high.

[0056] The third plane 25 may be connected to the upper surface 3, or may be separated from the upper surface 3. Figure 4 When the third plane 25 is connected to the upper surface 3, as in the non-limiting example shown, the area of ​​the third plane 25 can be easily increased. Consequently, the wall thickness between the through-hole 9 and the first side surface 19 can be easily maintained, resulting in improved durability of the blade 1. Furthermore, the blade 1 can be easily and stably fixed to the handle. Consequently, the blade 1 is stabilized with increased stability.

[0057] When observing the first side surface 19 from the front view, the first boundary 33 between the first plane 21 and the second plane 23 may be inclined relative to the central axis O1, or may be parallel to the central axis O1. Figure 4 As shown in the non-limiting example, when the first boundary 33 is parallel to the central axis O1, the thickness variation of the insert 1 between the first and second planes 21 and 23 and the through hole 9 is small. Therefore, the durability of the insert 1 is high.

[0058] When observing the first side surface 19 from the front view, the second boundary 35 between the first plane 21 and the third plane 25 may be inclined relative to the central axis O1, or may be parallel to the central axis O1. Figure 4 As shown in the non-limiting example, when the second boundary 35 is parallel to the central axis O1, the thickness variation of the insert 1 between the first and third planes 21 and 25 and the through hole 9 is small. Therefore, the durability of the insert 1 is high.

[0059] The area of ​​the first plane 21 may be smaller than the area of ​​the second plane 23 and the area of ​​the third plane 25. The area of ​​the second plane 23 and the area of ​​the third plane 25 may be the same as each other, or may be different.

[0060] The first plane 21 may be located outside the second plane 23 and the third plane 25 in a plan view. Alternatively, the first plane 21 may be located at the outermost side of the first side surface 19 in a plan view.

[0061] The length L11 of the first plane 21 along the long side 13 may be shorter than the length L12 of the second plane 23 along the long side 13 and the length L13 of the third plane 25 along the long side 13. It should be noted that the length L11 can be evaluated using the maximum value of the lengths L11. This also applies to the lengths L12 and L13.

[0062] Examples of materials for the insert 1 include cemented carbide and cermet. Examples of cemented carbide compositions include WC-Co, WC-TiC-Co, and WC-TiC-TaC-Co. WC, TiC, and TaC may be hard particles, and Co may be a binder phase.

[0063] In addition, cermet can also be a sintered composite material made by combining metal and ceramic components. As an example of cermet, a titanium compound with titanium carbide (TiC) or titanium nitride (TiN) as the main component can be cited. Of course, the material of the blade 1 is not limited to the above composition.

[0064] The surface of the blade 1 can be coated with a film using a chemical vapor deposition (CVD) method or a physical vapor deposition (PVD) method. Examples of the film composition include titanium carbide (TiC), titanium nitride (TiN), titanium carbonitride (TiCN), and aluminum oxide (Al2O3).

[0065] <Cutting tools>

[0066] Next, use Figures 10 to 13 The cutting tool 101 according to one non-limiting aspect of the present disclosure will be described. Figure 10 In FIG. 1 and FIG. 2 , the rotation axis O2 of the cutting tool 101 is indicated by a two-dot chain line, and the rotation direction of the rotation axis O2 is indicated by an arrow Y1.

[0067] like Figures 10 to 13 As shown in the non-limiting example, the cutting tool 101 may include a shank 103 and an insert 1. When the cutting tool 101 includes the insert 1, the insert 1 has high durability and can therefore exhibit excellent cutting performance.

[0068] The cutting tool 101 may be rotatable around a rotation axis O2. In addition, the cutting tool 101 may be used for rotary cutting.

[0069] The tool handle 103 may be in the shape of a cylinder extending from the first end 103a to the second end 103b along the rotation axis O2. The cylinder shape only needs to be substantially cylindrical and does not need to be strictly cylindrical.

[0070] The handle 103 may have a knife groove 105 located on the first end 103a side. The knife groove 105 may be a portion where the blade 1 can be mounted. The knife groove 105 may also be open on the outer peripheral surface of the handle 103 and the end surface on the first end 103a side.

[0071] The blade 1 can be located in the knife groove 105. It should be noted that there can be only one knife groove 105, or there can be multiple knife grooves. Figure 11 As shown in the non-limiting example, when the shank 103 has a plurality of grooves 105 , the cutting tool 101 may have a plurality of inserts 1 , and one insert 1 may be located in each groove 105 .

[0072] When the tool holder 103 has a plurality of sipes 105 , these sipes 105 may be arranged at equal intervals around the rotation axis O2 , or may be arranged at unequal intervals.

[0073] The insert 1 can be mounted on the knife groove 105 in a manner such that at least a portion of the cutting edge 11 protrudes from the knife handle 103. For example, the insert 1 can also be mounted on the knife handle 103 in a manner such that the cutting edge 11 protrudes from the knife handle 103 toward the workpiece. In this case, the lower surface 5 and the side surface 7 can abut against the knife handle 103.

[0074] The blade 1 can be installed in the knife groove 105 by a screw 107. That is, the screw 107 can be inserted into the through hole 9 of the blade 1, the front end of the screw 107 is inserted into the threaded hole formed in the knife groove 105, and the screw 107 is fixed to the threaded hole, thereby the blade 1 is installed on the handle of a knife 103.

[0075] Examples of the material of the bracket 103 include steel and cast iron. When the handle 103 is made of steel, the handle 103 has high toughness.

[0076] <Method for Manufacturing Machined Product>

[0077] Next, use Figures 14 to 16 A method for manufacturing the machined product 203 , which is one aspect not limited to the present disclosure, will be described.

[0078] The machined product 203 can be manufactured by machining the workpiece 201. The method for manufacturing the machined product 203 may include the following steps.

[0079] (1) a step of rotating the cutting tool 101 represented by the above-mentioned non-limiting embodiment;

[0080] (2) a step of bringing the rotating cutting tool 101 into contact with the workpiece 201; and

[0081] (3) A step of separating the cutting tool 101 from the workpiece 201 .

[0082] Specifically, first, Figure 14 As shown in the non-limiting example, the cutting tool 101 can be relatively brought close to the workpiece 201 while rotating about the rotation axis O2 in the Y1 direction. Figure 15 As shown in the non-limiting example, the cutting edge 11 of the cutting tool 101 can be brought into contact with the workpiece 201 to cut the workpiece 201. Figure 16 As shown in the non-limiting example, the cutting tool 101 may be relatively separated from the workpiece 201 .

[0083] By going through the above steps, excellent machinability can be achieved. Specifically, in the method for producing a machined product 203 according to one aspect of the present disclosure, which is not limited, when a cutting tool 101 having an insert 1 is used, the insert 1 has high durability. Therefore, a machined product 203 with a high precision finished surface can be obtained.

[0084] It should be noted that in Figures 14 to 16 In the illustrated non-limiting example, the workpiece 201 is fixed and the cutting tool 101 is moved in each step, but the present invention is not limited to this embodiment.

[0085] For example, in step (1), the workpiece 201 can be brought closer to the cutting tool 101. Similarly, in step (3), the workpiece 201 can be moved away from the cutting tool 101. While the cutting process is continued, the cutting tool 101 can be kept rotating, and the process of bringing the cutting edge 11 of the insert 1 into contact with different parts of the workpiece 201 can be repeated.

[0086] Examples of the material of the workpiece 201 include carbon steel, alloy steel, stainless steel, cast iron, and non-ferrous metals.

[0087] Description of Reference Numerals

[0088] 1...Cutting blade (blade)

[0089] 3...Upper surface

[0090] 5...lower surface

[0091] 7...Side

[0092] 9...Through hole

[0093] 11...Cutting edge

[0094] 13...long side

[0095] 15...short side

[0096] 17...corner

[0097] 19...First side

[0098] 21...First plane

[0099] 23...Second Plane

[0100] 25...the third plane

[0101] 27...First inclined surface

[0102] 29... Ridge

[0103] 31...Second inclined surface

[0104] 33...The First Boundary

[0105] 35...The Second Frontier

[0106] 101...Cutting tools

[0107] 103...Handle

[0108] 103a..First end

[0109] 103b..Second end

[0110] 105...Knife groove

[0111] 107...screw

[0112] 201...Working parts

[0113] 203...Cutting workpiece

[0114] O1...Center axis

[0115] O2...rotation axis.

Claims

1. A cutting insert, wherein: The cutting insert has: an upper surface, which is polygonal in shape with long and short sides; a lower surface located on an opposite side of the upper surface; a side surface located between the upper surface and the lower surface; a through hole opening at the center of the upper surface and the center of the lower surface; as well as The cutting edge, which is located on the short side, The side surface includes a first side surface that is located along the long side and is convex outward in a plan view. The first side has: a first plane, which coincides with the central axis of the through hole when viewed from the front and is parallel to the central axis; a second plane connected to the lower surface and located closer to the short side than the first plane and parallel to the central axis; a third plane located farther from the short side than the first plane and parallel to the central axis; and a first inclined surface, located between the second plane and the upper surface, and approaching the central axis as it approaches the long side; The first inclined surface is separated from the first plane.

2. The cutting insert according to claim 1, wherein The first inclined surface has a portion whose inclination angle with respect to the central axis decreases as it approaches the first plane.

3. The cutting insert according to claim 1 or 2, wherein: The first inclined surface has a portion whose width along the direction of the central axis decreases as it approaches the first plane.

4. The cutting insert according to claim 1 or 2, wherein When the first side surface is viewed in plan, the first inclined surface is located closer to the short side than the through hole.

5. The cutting insert according to claim 1 or 2, wherein The first side surface further has a second inclined surface located between the third plane and the lower surface and moving away from the central axis as it approaches the long side. The second inclined surface is separated from the first plane.

6. The cutting insert according to claim 1 or 2, wherein The third plane is connected to the upper surface.

7. The cutting insert according to claim 1 or 2, wherein: When the first side surface is viewed from the front, a first boundary between the first plane and the second plane is parallel to the central axis.

8. A cutting tool, wherein: The cutting tool has: a tool handle having a cylindrical shape extending from a first end to a second end along a rotation axis and having a tool groove located on the first end side; and The cutting insert according to any one of claims 1 to 7 is located in the groove.

9. A method for producing a machined product, wherein: The method for manufacturing the machined product comprises: a step of rotating the cutting tool according to claim 8; a step of bringing the rotating cutting tool into contact with a workpiece; and a step of separating the cutting tool from the workpiece.

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