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

Abstract

A cutting insert according to one aspect of the present disclosure includes: an upper face that has a rake face region; a lower face that faces the opposite side from the upper face; a tip end face that is located on the tip end side and has a flank face region; a rear end face that is located on the rear end side; and a first flow path that extends from the tip end face to the rear end face. The first flow path includes: a first region that extends from the tip end face toward the rear end side and has an inner diameter increasing toward the rear end side; and a second region that extends from the rear end face toward the tip end side and has an inner diameter increasing toward the tip end side.

Description

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

[0001] This application claims priority to Japanese Patent Application No. 2023-048470, filed on March 24, 2023, the entire disclosure of which is incorporated herein by reference.

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

[0003] Known cutting inserts for cutting tools used when cutting a workpiece include those described in, for example, Japanese Patent Laid-Open Nos. 2022-046273 (Patent Document 1) and 2001-198708 (Patent Document 2). The cutting inserts described in Patent Documents 1 and 2 have a flow path therein through which a coolant flows to cool the cutting insert.

[0004] In both of the cutting inserts described in Patent Documents 1 and 2, the flow passages are open on the flank surface. In such cases, there is a demand for further improvement in the cooling effect of the cutting edge.

[0005] A cutting insert according to one aspect of the present disclosure is a cutting insert extending from a leading end to a trailing end along a reference axis, and having an upper surface having a cutting surface region, a lower surface facing the opposite side to the upper surface, a leading end surface located on the leading end side and having a clearance region, a trailing end surface located on the trailing end side, and a first flow path extending from the leading end surface to the trailing end surface, wherein the first flow path has a first region extending from the leading end surface toward the trailing end side and having an inner diameter that increases toward the trailing end side, and a second region extending from the trailing end surface toward the leading end side and having an inner diameter that increases toward the leading end side.

[0006] 1 is a perspective view showing a cutting insert according to an embodiment of the present disclosure; FIG. 2 is a see-through plan view of the cutting insert shown in FIG. 1; FIG. 3 is a plan view of the cutting insert shown in FIG. 2 as viewed from the A1 direction; FIG. 4 is a plan view of the cutting insert shown in FIG. 2 as viewed from the A2 direction; FIG. 5 is a perspective view of a cutting tool according to an embodiment of the present disclosure; FIG. 6 is an enlarged view of region B1 shown in FIG. 7; FIG. 7 is a plan view of the cutting tool holder shown in FIG. 8; FIG. 8 is a see-through plan view of the cutting tool shown in FIG. 5; FIG. 9 is an enlarged view of region B2 shown in FIG. 10; FIG. 11 is a diagram showing a step in a method of manufacturing a machined product according to an embodiment of the present disclosure; FIG. 12 is a diagram showing a step in a method of manufacturing a machined product according to an embodiment of the present disclosure;

[0007] Hereinafter, a cutting insert 1 (hereinafter referred to as insert 1) according to a non-limiting embodiment of the present disclosure, a cutting tool holder 101 (hereinafter referred to as holder 101), a cutting tool 201, and a method for manufacturing a machined product 303 will be described in detail with reference to the drawings. However, for the sake of convenience, the drawings referred to below show only the main components necessary for explaining the insert 1 according to each embodiment in a simplified form. Therefore, the insert 1 according to the present disclosure may include any components not shown in the drawings. Furthermore, the dimensions of the components in the drawings do not faithfully represent the actual dimensions of the components and the dimensional ratios of the components.

[0008] <Insert> As shown in a non-limiting example in Figure 1, the insert 1 according to this embodiment has a first surface 3 (top surface 3), a second surface 5 (bottom surface 5) facing the opposite side of the first surface 3, i.e., located on the opposite side of the first surface 3, and a third surface 7 (side surface 7) located between the first surface 3 and the second surface 5.

[0009] The first surface 3, the second surface 5, and the third surface 7 may be polygonal, and each of the first surface 3, the second surface 5, and the third surface 7 has a plurality of corners and a plurality of sides.

[0010] The insert 1 according to this embodiment has a rectangular columnar shape extending from a first end 1a to a second end 1b along a reference axis O1, and more specifically, has a substantially convex shape. The reference axis O1 is an axis passing through the center of the insert 1. Hereinafter, for convenience of explanation, the first end 1a will be referred to as the leading end 1a, and the second end 1b will be referred to as the rear end 1b.

[0011] Here, Fig. 2 is a plan view seen through the insert 1 shown in Fig. 1. More specifically, it is a plan view seen through the flow path inside the insert 1. Fig. 3 is a plan view seen from the A1 direction of the insert 1 shown in Fig. 2. Fig. 4 is a plan view seen from the A2 direction of the insert 1 shown in Fig. 2.

[0012] Furthermore, the insert 1 according to this embodiment may have a cutting edge portion 9 located on the side of the front end 1a and a clamp portion 11 to which the cutting edge portion 9 is attached. The cutting edge portion 9 is a portion where the cutting edge 13 is located. The cutting edge portion 9 may be located in two places, on the side of the front end 1a and the side of the rear end 1b.

[0013] The clamp portion 11 is a portion that abuts against the holder 101 in the up-down direction, and the insert 1 is fixed to the holder 101 by clamping the clamp portion 11 to the holder 101. In the insert 1, the portion that abuts against the holder 101 is not limited to the clamp portion 11, and for example, the lower surface of the cutting edge portion 9 may abut against the holder 101. Furthermore, as in a non-limiting example shown in Figure 1, the clamp portion 11 may be located between a pair of cutting edge portions 9 in the direction along the reference axis O1.

[0014] Here, the vertical direction is a direction along a vertical axis O2 that passes through the center of the first surface 3 and the center of the second surface 5. In the insert 1 according to this embodiment, the vertical axis O2 is perpendicular to the reference axis O1. The vertical axis O2 may intersect with the reference axis O1. The cutting edge portion 9 and the clamp portion 11 may be integrally formed, as in the insert 1 according to this embodiment.

[0015] As in the insert 1 according to this embodiment, the first surface 3 may include a cutting edge upper surface 15 located in the cutting edge portion 9, or a clamping upper surface 17 located in the clamping portion 11. The clamping upper surface 17 may be located above the cutting edge upper surface 15. In the insert 1 according to this embodiment, the clamping upper surface 17 and the second surface 5 each have a recess in the central portion that extends along the reference axis O1.

[0016] In the insert 1 according to this embodiment, the third surface 7 may have a leading edge face 19 located on the leading edge 1a side, or a rear edge face 21 located on the rear edge 1b side. The leading edge face 19 may face the leading edge 1a side, and the rear edge face 21 may face the rear edge 1b side. The third surface 7 may further have a cutting edge side face 23 connected to the cutting edge upper surface 15 and the leading edge face 19.

[0017] The insert 1 has a cutting edge 13 located at the intersection of the first surface 3 and the third surface 7. In the insert 1 according to this embodiment, the cutting edge 13 has a major cutting edge located at the intersection of the cutting edge upper surface 15 and the tip surface 19, and a minor cutting edge located at the intersection of the cutting edge upper surface 15 and the cutting edge side surface 23. The cutting edge side surface 23 may be located below the cutting edge upper surface 15. As a non-limiting example shown in FIG. 1 , the cutting edge side surface 23 may be flush with the side surface 7 (clamp side surface 24) of the clamp portion 11 to form the same plane. The first surface 3 (cutting edge upper surface 15) may have a rake face region 25, and the third surface 7 (tip surface 19, cutting edge side surface 23) may have a relief face region 26.

[0018] The insert 1 may also have through holes that open to the first surface 3 and the second surface 5. The through holes are used as holes into which fasteners are inserted when the insert 1 is attached to the holder 101. Examples of fasteners include screws, clamp members, and wedges.

[0019] The through-hole is not limited to the above configuration, and may, for example, open in the third surface 7. In this case, the through-hole may penetrate from one of the plurality of flat portions of the third surface 7 to another flat portion located on the opposite side.

[0020] The insert 1 has a first flow passage 27. The first flow passage 27 is located inside the insert 1 and is configured to supply coolant during cutting. There are no particular limitations on the method for forming the first flow passage 27. For example, the first flow passage 27 may be formed in the insert 1 by drilling, laser processing, manufacturing using a 3D printer, or the like.

[0021] Here, examples of coolants include water-insoluble oils and water-soluble oils. Examples of water-insoluble oils include cutting oils such as oil-based, inactive extreme pressure, and active extreme pressure types. Examples of water-soluble oils include cutting oils such as emulsions, solubles, and solutions. Note that the coolant is not limited to a liquid, and may be a gas such as an inert gas.

[0022] 2 , the first flow passage 27 may have a first opening 29 that opens at the leading end surface 19, and may have a second opening 31 that opens at the trailing end surface 21. The first opening 29 is configured to discharge the coolant that has flowed from the first flow passage 27 to the outside. The second opening 31 is configured to allow the coolant that has flowed from the holder 101 to flow into the first flow passage 27 of the insert 1.

[0023] The first flow passage 27 has a first region 33 extending from the tip end face 19 toward the rear end 1b. The first region 33 has an inner diameter that increases toward the rear end 1b. The first flow passage 27 also has a second region 35 extending from the rear end face 21 toward the tip 1a. The second region 35 has an inner diameter that increases toward the tip 1a. In this case, the flow rate is less likely to slow down between the first region 33 and the second region 35. The insert 1 is also more easily cooled from the inside. Coolant can be efficiently supplied to the cutting edge 13.

[0024] The first region 33 may be inclined with respect to the second region 35. For example, when the first region 33 is connected to the second region 35, the flow velocity is less likely to slow down at the connection point between the first region 33 and the second region 35. Here, the first region 33 being inclined with respect to the second region 35 refers to a case where a central axis N1 of the first region 33 and a central axis N2 of the second region 35 form an angle. Here, when the angle formed by the central axis N1 and the central axis N2 is an obtuse angle, the flow velocity is even less likely to slow down at the connection point between the first region 33 and the second region 35.

[0025] The center axis N1 of the first region 33 may be spaced further from the first surface 3 as it moves toward the rear end 1b. In this case, it is easier to discharge coolant more efficiently toward the cutting edge 13. Furthermore, the center axis N2 of the second region 35 may be spaced further from the first surface 3 as it moves toward the front end 1a. In this case, the gap between the first surface 3 and the second region 35 does not become excessively thin, which makes it easier to reduce the risk of deformation of the first flow path 27.

[0026] The first region 33 may be connected to the second region 35. In such a case, the number of times the inner diameter of the entire flow path changes from large to small is small, which further reduces the risk of the flow rate slowing down. Furthermore, the first region 33 may be connected to the first opening 29 or the second region 35. The first region 33 may be connected to the second region 35 via a central region 45, which will be described later.

[0027] The first region 33 may have a first flow path wall 37 located on the side of the first surface 3. The first flow path wall 37 may be spaced apart from the first surface 3 as it moves toward the rear end 1b. In this case, it is easier to discharge the coolant toward the cutting edge 13 more efficiently.

[0028] Furthermore, the second region 35 may have a second flow path wall 39 located on the first surface 3 side. The second flow path wall 39 may be connected to the first flow path wall 37. The second flow path wall 39 may be spaced further away from the first surface 3 as it moves toward the tip 1a. In such a case, the gap between the first surface 3 and the second region 35 does not become excessively thin, which makes it easier to reduce the risk of deformation of the first flow path 27. The second flow path wall 39 may be connected to the first flow path wall 37 via the central region 45.

[0029] The first region 33 may further include a third flow path wall 41 located on the second surface 5 side. The second region 35 may also include a fourth flow path wall 43 located on the second surface 5 side. The fourth flow path wall 43 may be connected to the third flow path wall 41. The fourth flow path wall 43 may be connected to the third flow path wall 41 via a central region 45.

[0030] Furthermore, when the second flow path wall 39 is connected to the first flow path wall 37, the fourth flow path wall 43 may be separated from the third flow path wall 41. In this case, a protrusion having a convex shape on the upper side may be provided between the third flow path wall 41 and the fourth flow path wall 43.

[0031] As a non-limiting example shown in FIG. 4 , in a cross section passing through the central axis N1 of the first region 33 and the central axis N2 of the second region 35, the angle θ1 between the first flow path wall 37 and the second flow path wall 39 may be larger than the angle θ2 between the third flow path wall 41 and the fourth flow path wall 43. In such a case, the risk of a slowdown in the flow rate is more likely to be reduced. Here, if a cross section passing through the central axis N1 of the first region 33 and the central axis N2 of the second region 35 is not uniquely determined, the magnitude relationship of the above angles may be evaluated when viewed from a planar perspective in a direction perpendicular to the reference axis O1 and the up-down axis O2 (left-right direction). Even when the above cross section is uniquely determined, the magnitude relationship of the above angles may be evaluated when viewed from the planar perspective.

[0032] The angles θ1 and θ2 are not limited to specific values. For example, the angle θ1 may be set to 150 to 180 degrees. The angle θ2 may be set to 140 to 180 degrees. The angles θ1 and θ2 may each be an obtuse angle.

[0033] The first flow passage 27 may further include a central region 45 located at the center of the first flow passage 27 in the direction along the reference axis O1. In the insert 1 according to this embodiment, the central region 45 may be located below the clamp upper surface 17. Here, the length from the second surface 5 to the clamp upper surface 17 in the up-down direction may be greater than the length from the second surface 5 to the cutting edge upper surface 15.

[0034] The first flow passage 27 may have a maximum inner diameter in the central region 45. In this case, the portion of the first flow passage 27 with the maximum inner diameter can be positioned in a portion of the insert 1 where the rigidity is relatively high, thereby reducing the risk of deformation of the first flow passage 27.

[0035] Depending on the conditions for forming the first flow passage 27, the flow passage walls of the first flow passage 27 (first flow passage wall 37, second flow passage wall 39, third flow passage wall 41, fourth flow passage wall 43, etc.) may be formed in a spiral shape or the like, and the inner diameter of the first flow passage may vary slightly from the leading end 1 a side to the rear end 1 b side. In such a case, a region of the first flow passage 27 where the central axis of the first flow passage 27 approaches the second surface 5 as it moves from the leading end 1 a side to the rear end 1 b side may be referred to as the first region 33, and a region of the first flow passage 27 where the central axis of the first flow passage 27 approaches the second surface 5 as it moves from the rear end 1 b side to the leading end 1 a side may be referred to as the second region 35.

[0036] Examples of materials for the insert 1 include cemented carbide, cermet, ceramics, cBN (Cubic Boron Nitride), and PCD (Polycrystalline Diamond).

[0037] Examples of cemented carbide compositions include WC (tungsten carbide)-Co, WC-TiC (titanium carbide)-Co, and WC-TiC-TaC (tantalum carbide)-Co. Here, WC, TiC, and TaC are hard particles, and Co is a binder phase. Cermets are sintered composite materials in which a ceramic component is combined with a metal. Specifically, cermets include compounds whose main component is TiC or TiN (titanium nitride). However, the material of the insert 1 is not limited to these.

[0038] Furthermore, the insert 1 may be made up of only one member made of the material exemplified above, or may be made up of multiple members made of the material exemplified above.

[0039] The insert 1 is not limited to a specific size. For example, the length of the insert 1 in the direction along the reference axis O1 may be set to approximately 13 to 30 mm. Furthermore, the width of the insert 1 in the direction perpendicular to the reference axis O1 when the first surface 3 is viewed from the front may be set to approximately 2 to 10 mm. The height of the insert 1 in the direction along the vertical axis O2 may be set to approximately 3 to 10 mm.

[0040] <Holder> Hereinafter, the holder 101 according to the embodiment of the present disclosure will be described in detail with reference to the drawings.

[0041] As a non-limiting example shown in Figures 5 to 10, a holder 101 according to an embodiment may be used for a grooving tool. The holder 101 may be rod-shaped. The holder 101 may include a main body portion 103 and a cutting portion 105. The main body portion 103 is a portion generally called a shank, and may be a portion that is gripped by a machine tool. The cutting portion 105 may be a portion to which an insert 1 or the like is attached.

[0042] Here, Fig. 5 is a perspective view showing a cutting tool 201 according to an embodiment of the present disclosure. Fig. 6 is an enlarged view of region B1 shown in Fig. 5. Fig. 7 is a plan view of the holder 101 shown in Fig. 6. More specifically, it is a plan view of the cutting tool 201 shown in Fig. 6 with the insert 1 removed. Fig. 8 is a see-through plan view of the cutting tool 201 shown in Fig. 5. More specifically, it is a see-through plan view of only the flow paths inside the insert 1 and the flow paths inside the holder 101 (including a tank for storing coolant). Fig. 9 is a plan view of the cutting tool 201 shown in Fig. 8 as viewed from direction A3. Fig. 10 is an enlarged view of region B2 shown in Fig. 9.

[0043] 5, the main body 103 is columnar and extends from the third end 101a to the fourth end 101b along the axis O3 of the holder 101. For ease of explanation, the third end 101a may be referred to as one end 101a, and the fourth end 101b may be referred to as the other end 101b. The axis O3 is an axis passing through the center of the main body 103. The direction in which the third end 101a is positioned relative to the fourth end 101b may be the same as the direction in which the front end 1a is positioned relative to the rear end 1b.

[0044] Furthermore, the direction in which the fourth end 101b is positioned relative to the third end 101a may be the same as the direction in which the rear end 1b is positioned relative to the front end 1a. Examples of the columnar shape include a cylindrical shape and a rectangular columnar shape. In one embodiment, the main body 103 is a square columnar shape. The square columnar shape does not only refer to a square columnar shape in the strict sense, but also includes slight irregularities and curvatures. The shape of the main body 103 is not limited to a square columnar shape.

[0045] The holder 101 according to this embodiment may have a holder upper surface 107 and a holder lower surface 109 located on the opposite side of the holder upper surface 107. In this case, the side of the holder upper surface 107 may be the above-mentioned upper side, the side of the holder lower surface 109 may be the above-mentioned lower side, and the direction along a straight line passing through the center of the holder upper surface 107 and the center of the holder lower surface 109 may be the above-mentioned up-down direction.

[0046] Cutting portion 105 may be located closer to third end 101 a than main body portion 103. Cutting portion 105 may also have upper jaw portion 111 located above, lower jaw portion 113 located below upper jaw portion 111, and pocket 115 located between upper jaw portion 111 and lower jaw portion 113. Upper jaw portion 111 may abut against first surface 3. More specifically, upper jaw portion 111 may abut against clamp upper surface 17. Lower jaw portion 113 may abut against second surface 5.

[0047] The cutting portion 105 may further include a screw hole 117. In one example, the screw hole 117 is a portion into which a screw 119 is inserted, and is located from the upper jaw portion 111 to the lower jaw portion 113. The insert 1 may be fixed by a clamping force obtained when the screw 119 is tightened with the insert 1 sandwiched between the upper jaw portion 111 and the lower jaw portion 113 and the upper jaw portion 111 is elastically deformed and pressed down. Note that the fixation of the insert 1 is not limited to a clamping mechanism that utilizes a clamping force.

[0048] Furthermore, the cutting portion 105 may have a slit 121 located between the upper jaw portion 111 and the lower jaw portion 113 in the vertical direction. The slit 121 may extend toward the fourth end 101b. Furthermore, the slit 121 may be open in the left-right direction. In the holder 101 according to this embodiment, the slit 121 is open at both ends of the cutting portion 105 in the left-right direction. Furthermore, the slit 121 may be located above the main body portion 103.

[0049] The insert 1 may be positioned in the pocket 115. The holder 101 may also have a restraining surface 123 that contacts the rear end surface 21. More specifically, the cutting portion 105 may have the restraining surface 123. There are no particular limitations on the shape of the restraining surface 123, but it may be a square shape.

[0050] The holder 101 may have a second flow path 125. More specifically, the cutting portion 105 may have the second flow path 125. The second flow path 125 is located inside the holder 101 and is configured to supply coolant to the cutting blade 13 during cutting. There are no particular limitations on the method for forming the second flow path 125, as with the first flow path 27. There are no particular limitations on the shape of the second flow path 125, but it may be linear.

[0051] The second flow path 125 may have a third opening 127 that opens at the restraint surface 123. The third opening 127 is configured to allow the coolant that has flowed from the second flow path 125 to flow into the first flow path 27. The second flow path 125 extends from the third opening 127 toward the fourth end 101b. The second flow path 125 may be located below the slit 121. In this case, the second flow path 125 is less susceptible to elastic deformation caused by the slit 121, and the coolant can be more efficiently discharged.

[0052] Examples of materials for the holder 101 include steel, cast iron, and aluminum alloy. When the holder 101 is made of steel, the holder 101 has high toughness. The size of the holder 101 can be set to the following values. The dimension of the holder 101 in the direction along the axis O3 is, for example, 90 to 180 mm.

[0053] <Cutting Tool> Next, a cutting tool 201 according to an embodiment of the present disclosure will be described with reference to the drawings.

[0054] 5 , the cutting tool 201 according to this embodiment includes a holder 101 having a pocket 115 on the side of the third end 101a, and an insert 1 according to this embodiment located in the pocket 115. In the cutting tool 201 according to this embodiment, the insert 1 is attached so that at least a portion of the cutting edge 13 protrudes from the side of the third end 101a of the holder 101. In the cutting tool 201 according to this embodiment, the clamping portion 11 is clamped by the upper jaw portion 111 and the lower jaw portion 113 of the holder 101. The insert 1 is attached so that the cutting edge 13 protrudes outward from the holder 101.

[0055] In this embodiment, a cutting tool 201 used for so-called grooving is illustrated. Examples of turning include internal diameter machining, external diameter machining, and grooving. The cutting tool 201 is not limited to one used for grooving. For example, the insert 1 and holder 101 according to the above embodiment may be used in a cutting tool 201 used for machining other than turning or for milling.

[0056] <Method for Manufacturing Machined Product> Next, a method for manufacturing the machined product 303 according to various embodiments of the present disclosure will be described in detail with reference to FIGS. 11 to 13. FIG.

[0057] The manufacturing method of the machined product 303 according to the embodiment includes the following steps (1) to (3).

[0058] (1) Rotating a workpiece 301, as shown in a non-limiting example in FIG.

[0059] (2) A step of contacting a cutting tool 201 with a rotating workpiece 301, as shown in a non-limiting example in FIG.

[0060] (3) A step of separating the cutting tool 201 from the workpiece 301, as shown in a non-limiting example in FIG.

[0061] Specifically, first, the workpiece 301 is rotated about its rotation axis S1 as a non-limiting example shown in Fig. 11. Examples of the material of the workpiece 301 include carbon steel, alloy steel, stainless steel, cast iron, and non-ferrous metals.

[0062] Next, the cutting tool 201 is moved in the direction of the arrow Y1 to bring the cutting tool 201 relatively close to the rotating workpiece 301.

[0063] 12 , the cutting edge 13 of the cutting tool 201 is brought into contact with the rotating workpiece 301 to cut the workpiece 301. At this time, the workpiece 301 may be cut while coolant is flowing out from the first opening 29.

[0064] Finally, as a non-limiting example shown in FIG. 13, the cutting tool 201 is moved in the direction of arrow Y2 to move the cutting tool 201 relatively away from the workpiece 301, thereby obtaining a machined product 303.

[0065] In the example embodiment, the cutting workpiece 303 is obtained by moving the cutting tool 201, but this is not limiting. For example, in step (1), the workpiece 301 may be brought closer to the cutting tool 201. Similarly, in step (3), the workpiece 301 may be moved away from the cutting tool 201. To continue the cutting process, the workpiece 301 may be kept rotating and the step of bringing the cutting blade 13 into contact with different locations on the workpiece 301 may be repeated.

[0066] Examples of materials for the workpiece 301 include carbon steel, alloy steel, stainless steel, cast iron, and non-ferrous metals.

[0067] In one embodiment, [1] the cutting insert is a cutting insert extending from the tip to the rear end along a reference axis, and has an upper surface having a cutting surface region, a lower surface facing opposite to the upper surface, a tip surface located on the tip side and having a clearance region, a rear end surface located on the rear end side, and a first flow path extending from the tip surface to the rear end surface, and the first flow path may have a first region extending from the tip surface toward the rear end side and having an inner diameter that increases toward the rear end side, and a second region extending from the rear end surface toward the tip side and having an inner diameter that increases toward the tip side.

[0068] [2] In the cutting insert according to the above [1], the first region may be inclined relative to the second region.

[0069] [3] In the cutting insert of [1] or [2] above, the central axis of the first region may be spaced apart from the upper surface as it moves toward the rear end, and the central axis of the second region may be spaced apart from the upper surface as it moves toward the front end.

[0070] [4] In the cutting insert according to any one of the above [1] to [3], the first region may be connected to the second region.

[0071] [5] In any of the cutting inserts [1] to [4] above, the first region may have a first flow path wall located on the side of the upper surface, and the second region may have a second flow path wall located on the side of the upper surface and connected to the first flow path wall, and the first flow path wall may be spaced apart from the upper surface as it moves towards the rear end, and the second flow path wall may be spaced apart from the upper surface as it moves towards the front end.

[0072] [6] In the cutting insert of [5] above, the first region may further have a third flow path wall located on the side of the lower surface, and the second region may further have a fourth flow path wall located on the side of the lower surface and connected to the third flow path wall, and in a cross section passing through the central axis of the first region and the central axis of the second region, the angle formed by the first flow path wall and the second flow path wall may be larger than the angle formed by the third flow path wall and the fourth flow path wall.

[0073] [7] In any of the cutting inserts [1] to [6] above, the first flow path may further have a central region located at the center of the first flow path in a direction along the reference axis, and the first flow path may have a maximum inner diameter in the central region.

[0074] [8] A cutting tool comprising a rod-shaped holder extending from one end to the other end along an axis, and a cutting insert according to any one of [1] to [7] above attached to the holder, wherein the holder may have a restraining surface in contact with the rear end surface, an opening located on the restraining surface and connected to the first flow path, and a second flow path extending from the opening toward the other end.

[0075] [9] A method for manufacturing a machined product may include the steps of rotating a workpiece, bringing the cutting tool described in [8] above into contact with the rotating workpiece, and removing the cutting tool from the workpiece.

[0076] The invention according to the present disclosure has been described above based on the drawings and embodiments. However, the invention according to the present disclosure is not limited to the above-described embodiments. In other words, the invention according to the present disclosure can be modified in various ways within the scope of the present disclosure, and embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the invention according to the present disclosure. In other words, it should be noted that a person skilled in the art can easily make various modifications or corrections based on the present disclosure.

[0077] It should also be noted that these variations and modifications are included within the scope of the present disclosure. In addition, the directions in the present disclosure are shown merely for the convenience of explanation, and even if the upside-down direction is reversed, this does not affect the invention according to the present disclosure.

[0078] DESCRIPTION OF SYMBOLS 1...Cutting insert (insert) 1a...First end (front end) 1b...Second end (rear end) 3...First surface (upper surface) 5...Second surface (lower surface) 7...Third surface (side surface) 9...Cutting edge portion 11...Clamp portion 13...Cutting edge 15...Cutting edge upper surface 17...Clamp upper surface 19...Front end surface 21...Rear end surface 23...Cutting edge side surface 24...Clamp side surface 25...Rake face region 26...Flank face region 27...First flow path 29...First opening 31...Second opening 33...First region 35...Second region 37...First flow path wall 39...Second flow path wall 41...Third flow path wall 43...Fourth flow path wall 45...Central region 101...Cutting tool holder (holder) 101a...Third end (one end) DESCRIPTION OF SYMBOLS 101b...Fourth end (other end) 103...Main body 105...Cutting portion 107...Upper surface of holder 109...Lower surface of holder 111...Upper jaw portion 113...Lower jaw portion 115...Pocket 117...Threaded hole 119...Screw 121...Slit 123...Restraint surface 125...Second flow path 127...Third opening 201...Cutting tool 301...Workpiece 303...Machine processed product O1...Reference axis O2...Up / down axis O3...Axis θ1...Angle between first flow path wall and second flow path wall θ2...Angle between third flow path wall and fourth flow path wall N1...Central axis of first region N2...Central axis of second region S1...Rotation axis of workpiece Y1, Y2...Movement direction

Claims

1. A cutting insert extending from a leading end to a trailing end along a reference axis, an upper surface having a rake face region; a lower surface facing opposite to the upper surface; a tip surface located on the tip side and having a clearance area; a rear end surface located on the rear end side; a first flow path extending from the tip end surface to the rear end surface, The first flow path is a first region extending from the tip surface toward the rear end and having an inner diameter increasing toward the rear end; a second region extending from the rear end surface toward the tip end side and having an inner diameter that increases toward the tip end side.

2. The cutting insert according to claim 1 , wherein the first region is inclined relative to the second region.

3. a central axis of the first region is spaced apart from the upper surface toward the rear end, The cutting insert according to claim 1 , wherein the central axis of the second region becomes increasingly distant from the upper surface toward the tip side.

4. The cutting insert according to claim 1 , wherein the first region connects with the second region.

5. the first region has a first flow path wall located on the upper surface side, the second region is located on the upper surface side and has a second flow path wall connected to the first flow path wall, the first flow path wall is spaced apart from the upper surface toward the rear end, The cutting insert according to claim 4 , wherein the second flow path wall is spaced apart from the upper surface toward the tip side.

6. the first region further includes a third flow path wall located on the lower surface side, the second region further includes a fourth flow path wall located on the lower surface side and connected to the third flow path wall, In a cross section passing through a central axis of the first region and a central axis of the second region, The cutting insert according to claim 5 , wherein an angle formed between the first flow path wall and the second flow path wall is larger than an angle formed between the third flow path wall and the fourth flow path wall.

7. the first flow path further includes a central region located at a center of the first flow path in a direction along the reference axis, The cutting insert according to claim 6 , wherein the first channel has a maximum inner diameter at the central region.

8. a rod-shaped holder extending from one end to the other end along an axis; A cutting tool comprising: the cutting insert according to any one of claims 1 to 7 attached to the holder; The holder is a restraining surface in contact with the rear end surface; an opening located on the restraint surface and connected to the first flow path; a second flow path extending from the opening toward the other end.

9. rotating the workpiece; bringing the cutting tool according to claim 8 into contact with the rotating workpiece; and removing the cutting tool from the workpiece.