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

Abstract

There is a demand for a cutting insert that enables performing cutting work on a cutting object under a wide range of cutting conditions. This cutting insert has a rod-shaped first portion and a second portion that protrudes from a leading end of the first portion. The second portion has an upper surface, a cutting edge, a rising surface, and a recessed curved connection surface. The rising surface is disposed at a location closer to the first portion as compared with the upper surface, and becomes tilted upward as the distance from the upper surface increases. The connection surface is disposed between the upper surface and the rising surface, and is connected to the upper surface and the rising surface. Further, in a cross-section that contains the bisector of a first vertex, a virtual extended line of the upper surface and a virtual extended line of the rising surface intersect with each other at an acute angle.

Description

Technical Field

[0001] The present disclosure relates to a cutting insert, a cutting tool, and a method for manufacturing a machined product, which are used for cutting a workpiece. Examples of the cutting of the workpiece include turning and milling. Examples of turning include external diameter machining, internal diameter machining, grooving, and parting.

Background Art

[0002] A cutting tool used for cutting a workpiece made of a metal material or the like is discussed, for example, in Patent Document 1. The cutting tool described in Patent Document 1 has a cutting insert and a holder. The cutting insert has a rake face, a flank face, a cutting edge, and a wall face. The rake face is inclined downward as it moves away from the cutting edge, and the wall face is inclined upward as it moves away from the rake face.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

[0004] The cutting insert according to the present disclosure has a rod-shaped first portion extending along a central axis from a tip end to a rear end, and a second portion protruding in a direction orthogonal to the central axis from the tip end. The second portion has a triangular shape when viewed from the front, and has an upper surface having a first corner protruding from the first portion, a first side extending from the first corner toward the first portion, and a second side extending from the first corner toward the first portion and located closer to the rear end portion than the first side. The cutting insert also has a cutting edge located at least partially at the first corner, the first side, and the second side, a rising surface located closer to the first portion than the upper surface and inclined upward as it moves away from the upper surface, an upper end surface located closer to the first portion than the rising surface, and a connecting surface having a concave curved surface shape located between the upper surface and the rising surface and connected to the upper surface and the rising surface. Further, in a cross section orthogonal to the upper end surface and including the bisector of the first corner, a virtual extension line of the upper surface and a virtual extension line of the rising surface intersect at an acute angle.

Brief Description of the Drawings

[0005]

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DETAILED DESCRIPTION OF THE INVENTION

[0006] The cutting insert 1 (hereinafter, also simply referred to as insert 1) according to a non-limiting aspect of the present disclosure will be described in detail with reference to the drawings. However, each of the drawings referred to below shows only the main members necessary for explaining a non-limiting embodiment for the sake of convenience of explanation, and is simplified. Therefore, the insert 1 may include any constituent members not shown in each of the drawings referred to. Also, the dimensions of the members in each drawing do not necessarily faithfully represent the dimensions of the actual constituent members and the dimensional ratios of the respective members.

[0007] <Cutting insert> As shown in a non-limiting example in FIG. 1, the insert 1 is generally rod-shaped as a whole and has a first portion 3 and a second portion 5. The first portion 3 is rod-shaped extending along the central axis O1 from the tip 3a to the rear end 3b, and is the base portion of the insert 1. The first portion 3 in a non-limiting example shown in FIG. 1 is generally cylindrical. By attaching this first portion 3 to a holder described later, the insert 1 is fixed to the holder.

[0008] In the present disclosure, the "central axis O1" refers to an axis along the longitudinal direction of the first part 3, and is an axis passing through at least the center on either the tip 3a side or the rear end 3b side in the first part 3. For example, when viewed from the rear end 3b side, the axis passing through the center of gravity of the first part 3 along the longitudinal direction may be regarded as the central axis O1.

[0009] The size of the first part 3 is not limited to a specific value. The length of the first part 3 in the direction along the central axis O1 can be set, for example, to 30 to 80 mm. The maximum value of the width of the first part 3 in the direction orthogonal to the central axis O1 can be set, for example, to 3 to 10 mm.

[0010] The second part 5 protrudes in a direction orthogonal to the central axis O1 from the part on the tip 3a side in the first part 3. At this time, the second part 5 does not necessarily protrude from the part including the tip 3a in the first part 3, but in a non-limiting example shown in FIG. 1, the second part 5 protrudes in a direction orthogonal to the central axis O1 from the part including the tip 3a in the first part 3.

[0011] The second part 5 has a cutting edge 7 as described later and plays a main role during the cutting process of the workpiece to be machined. Therefore, the first part 3 in the insert 1 may be called the base part, and the second part 5 may be called the cutting part. The first part 3 and the second part 5 may be separate members, or may be integrally formed. In a non-limiting example shown in FIG. 1, the first part 3 and the second part 5 are integrally formed.

[0012] The second part 5 has an upper surface 9, a cutting edge 7, a rising surface 11, an upper end surface 5a, and a connecting surface 13. The upper surface 9 has a triangular shape having a first corner 15, a first side 17, and a second side 19. The first corner 15 on the upper surface 9 protrudes in a direction orthogonal to the central axis O1. Therefore, the first corner 15 is the farthest from the first part 3 on the upper surface 9. The first corner 15 does not necessarily need to be a corner in a strict sense. The first corner 15 in a non-limiting example shown in FIG. 3 has a convex curve shape protruding in a direction away from the first part 3. The first corner 15 may have an arc shape.

[0013] The first side 17 and the second side 19 each extend from the first corner 15. The first side 17 and the second side 19 each extend from the first corner 15 toward the first part 3. The distance between the first side 17 and the second side 19 widens as it moves away from the first corner 15. In a non-limiting example shown in FIG. 3, the first side 17 is located on the side of the tip 3a, and the second side 19 is located on the side of the rear end 3b. That is, the second side 19 is located closer to the rear end 3b than the first side 17. The first side 17 and the second side 19 may each be linear.

[0014] The size of the upper surface 9 is not limited to a specific value. The width of the upper surface 9 in the direction along the central axis O1 when viewed from the front can be set, for example, to 0.1 to 3 mm. The width of the upper surface 9 in the direction perpendicular to the central axis O1 when viewed from the front can be set, for example, to 0.08 to 2 mm. In the present disclosure, viewing the upper surface 9 from the front may be alternatively referred to as top view.

[0015] The first side 17, the second side 19, and the first corner 15 on the upper surface 9 are separated from the first part 3 and constitute the outer edge of the insert 1 when viewed from the top. The cutting edge 7 is located at at least a part of these first side 17, second side 19, and first corner 15. By bringing the cutting edge 7 into contact with the workpiece, cutting of the workpiece can be performed.

[0016] The rising surface 11 is a surface located closer to the first part 3 than the upper surface 9 and is inclined with respect to the upper surface 9. Specifically, the rising surface 11 is inclined upward as it moves away from the upper surface 9. The rising surface 11 is a surface located in front of the traveling direction of the chips generated by the cutting edge 7, and the chips can contact the rising surface 11. By bringing the chips into contact with the rising surface 11, control of the chips such as slowing down the flow rate of the chips, changing the flow direction of the chips, and deforming the chips can be performed.

[0017] The upper end surface 5a is a surface located closer to the first part 3 than the rising surface 11 and is the uppermost surface in the second part 5. In a non-limiting example shown in FIG. 5, the upper end surface 5a is flat. Also, in a non-limiting example shown in FIG. 10, the upper end surface 5a is parallel to the central axis O1. When the upper end surface 5a is parallel to the central axis O1, it may be used as a reference surface for adjusting the position of the cutting edge 7 in the vertical direction.

[0018] In a non-limiting example shown in FIG. 10, the upper surface 9 is slightly inclined with respect to the upper end surface 5a. Specifically, when the upper end surface 5a is used as a reference surface, the upper surface 9 is slightly inclined downward as it approaches the rear end 3b.

[0019] The connecting surface 13 is located between the upper surface 9 and the rising surface 11 and is connected to the upper surface 9 and the rising surface 11. In a non-limiting example shown in FIG. 2, while the upper surface 9 and the rising surface 11 are flat, the connecting surface 13 has a concave curved surface shape. Specifically, in a cross-section (hereinafter, also referred to as the first cross-section) that is orthogonal to the upper end surface 5a and includes the bisector of the first angle 15, while the upper surface 9 and the rising surface 11 are shown as straight lines, the connecting surface 13 is shown as a concave curve. The surface formed by the upper surface 9, the rising surface 11, and the connecting surface 13 in the second part 5 is concave as a whole.

[0020] The bisector of the first angle 15 may be replaced, for example, with the bisector of the angle formed by the tangents at both ends of the first angle when the first angle 15 has a convex curve shape or an arc shape. Also, for example, when the first angle 15 is connected to the first side 17 and the second side 19 and the first side 17 and the second side 19 are straight lines, the angle formed by the virtual extension lines obtained by extending the first side 17 and the second side 19 may be replaced with the bisector of the first angle 15. Also, the cross-section including the bisector of the first angle 15 is a cross-section that includes the entire bisector of the first angle 15. In the cutting tool of the present disclosure, for convenience of explanation, a part of the above-described first cross-section is enlarged and shown in the drawing.

[0021] In a non-limiting example shown in FIG. 10, the upper surface 9 is slightly inclined with respect to the upper end surface 5a. Therefore, the first cross-section is orthogonal to the upper end surface 5a while being inclined with respect to the upper surface 9. Here, the "inclination" is intended to mean neither orthogonal nor parallel. The first cross-section may be inclined with respect to the upper surface 9 while being orthogonal to the rising surface 11.

[0022] When the insert 1 does not have the connecting surface 13 and the upper surface 9 and the rising surface 11 are connected, chips may accumulate near the boundary between the upper surface 9 and the rising surface 11. However, the presence of the concave curved surface-shaped connecting surface 13 between these upper surface 9 and rising surface 11 makes chip clogging less likely to occur.

[0023] The second part 5 may have a side surface 21. The side surface 21 is connected to the first corner 15, the first side 17, and the second side 19 on the upper surface 9. Therefore, it may also be said that the cutting edge 7 is located at the intersection of the upper surface 9 and the side surface 21. The side surface 21 located along the cutting edge 7 may function as a so-called relief surface. Also, when the side surface 21 functions as a relief surface, the upper surface 9 may function as a so-called rake surface.

[0024] The side surface 21 may have a first side surface 21a, a second side surface 21b, and a corner side surface 21c. The first side surface 21a is connected to the first side 17. The second side surface 21b is connected to the second side 19. The corner side surface 21c is connected to the first corner 15. The first side surface 21a connected to the first side 17 and the second side surface 21b connected to the second side 19 may each be flat. When the side surface 21 functions as a relief surface, the first side surface 21a and the second side surface 21b may approach each other as they move away from the upper surface 9. When the first corner 15 has a convex curve shape as described above, the corner side surface 21c connected to the first corner 15 may have a convex curved surface shape.

[0025] As in the non-limiting example shown in FIG. 11, in the first cross-section, the virtual extension line L1 of the upper surface 9 and the virtual extension line L2 of the rising surface 11 may intersect at an acute angle. When these virtual extension lines L1 and L2 intersect at an obtuse angle, depending on the cutting conditions, it becomes difficult to sufficiently slow down the flow rate of the chips on the rising surface 11. Therefore, there is a risk that chip control becomes difficult when the chips cross the rising surface 11.

[0026] However, when the virtual extension lines L1 and L2 intersect at an acute angle, the flow rate of the chips can be sufficiently slowed down, and the chips are also likely to curl. When the chips travel along the upper surface 9, the chips tend to travel parallel to the upper surface 9. Also, when the chips travel along the rising surface 11, the chips tend to travel parallel to the rising surface 11. Here, the traveling direction of the chips when traveling along the rising surface 11 includes a component that is reversed with respect to the traveling direction of the chips when traveling along the upper surface 9. Therefore, as described above, the chips are likely to curl.

[0027] The angle θ at which the virtual extension lines L1 and L2 intersect in the first cross-section is not limited to a specific value as long as it is an acute angle. The angle θ may be set, for example, to about 75° to 89.8°. When the angle θ is 75° or more, chips are less likely to clog at the connecting surface 13. Also, when the angle θ is 89.8° or less, the chips are likely to curl stably.

[0028] When the entire upper surface 9 and the entire rising surface 11 are not flat, respectively, the virtual extension lines L1 and L2 may be evaluated by the following procedure. First, in the first cross-section, identify the tangent line that contacts the upper surface 9 and the connecting surface 13 at the boundary between the upper surface 9 and the connecting surface 13. This tangent line may be used as the virtual extension line L1. Also, in the first cross-section, identify the tangent line that contacts the rising surface 11 and the connecting surface 13 at the boundary between the rising surface 11 and the connecting surface 13. This tangent line may be used as the virtual extension line L2.

[0029] In a non-limiting example shown in FIG. 6, the connecting surface 13 has a groove shape extending in a direction inclined with respect to the central axis O1. At this time, the groove-shaped connecting surface 13 may be inclined so as to move away from the central axis O1 as it approaches the rear end 3b.

[0030] The inclination angle φ1 of the extending direction of the connecting surface 13 with respect to the central axis O1 when viewed from above is not limited to a specific value, and may be 0° < θ < 90°. In particular, when the inclination angle φ1 is 0° < θ < 45°, the chip evacuation property is excellent. This is because when the direction in which the chip contacts and flows on the connecting surface 13 changes, if the inclination angle φ1 is greater than 45°, the chip easily flows in a direction perpendicular to the central axis O1, but if the inclination angle φ1 is less than 45°, the chip easily flows toward the rear end 3b.

[0031] Generally, the portion located on the first side 17 of the cutting edge 7 is called the main cutting edge 7 and is often used as the main edge in cutting. This is because the chips generated by the main cutting edge 7 located on the first side 17 easily travel toward the rear end 3b, and the chip evacuation property is excellent. And when the groove-shaped connecting surface 13 is inclined as described above, the chips traveling toward the rear end 3b easily contact the connecting surface 13. Therefore, the flow of the chips is easily controlled on the connecting surface 13.

[0032] From the viewpoint of improving the chip evacuation property, the rising surface 11 may be inclined with respect to the central axis O1 so as to move away from the central axis O1 as it approaches the rear end 3b when viewed from above. In this case, the chips traveling toward the rear end 3b easily contact the rising surface 11. Therefore, the flow of the chips is easily controlled on the rising surface 11.

[0033] The upper surface 9 may be parallel to the central axis O1 or may be inclined. For example, as shown in a non-limiting example in FIG. 12, the upper surface 9 may be inclined downward as it approaches the rear end 3b. In FIG. 12, in order to facilitate the visual understanding of the inclination angle φ2, a virtual straight line O2 parallel to the central axis O1 is set, and the inclination angle φ2 is indicated by the angle formed by this virtual straight line O2 and the upper surface 9. When the upper surface 9 is inclined in this way, the chips are likely to progress toward the rear end 3b, and the chip discharge property is excellent.

[0034] When the connecting surface 13 is in a groove shape, the connecting surface 13 may open to the second side surface 21b. The chips with the flow controlled on the connecting surface 13 can stably progress toward the rear end 3b, and it is easy to obtain the insert 1 with excellent chip discharge property. Also, the connecting surface 13 may open to the first side surface 21a.

[0035] Depending on the structure of the workpiece, it may be required to discharge the chips toward the tip 3a side. When the connecting surface 13 opens to the first side surface 21a, the chip discharge property is excellent even when the chips progress toward the tip 3a. That is, when the connecting surface 13 opens to the first side surface 21a and the second side surface 21b, the insert 1 is less restricted by the structure of the workpiece and has excellent versatility.

[0036] As shown in a non-limiting example in FIG. 10, the width W1 of the rising surface 11 may increase as it moves away from the first side 17 and approaches the second side 19. When the chips flow toward the rear end 3b, as they approach the rear end 3b, in other words, as they move away from the first side 17 and approach the second side 19, the variation in the flow direction of the chips tends to increase. Here, when the width W1 of the rising surface 11 has the above configuration, even if the flow direction of the chips varies, the flow of the chips can be stably controlled. Also, since the overall width W1 of the rising surface 11 is not large, the miniaturization of the insert 1 can be achieved.

[0037] Also, as in a non-limiting example shown in FIG. 6, the width W2 of the connection surface 13 may be constant from the first side 17 toward the second side 19. When the chip contacts the connection surface 13 having a concave curved surface shape, the chip is likely to curl. When the width W2 of the connection surface 13 changes as it moves away from the first side 17 and approaches the second side 19, the chip is likely to curl so as to have a frustum of a cone shape as a whole. Therefore, the chips are likely to form large chunks. On the other hand, when the width W2 of the connection surface 13 is constant as described above, the chip is likely to have an elongated shape such as a spiral shape as a whole. Therefore, chip evacuation performance is excellent.

[0038] In a first cross section, as in a non-limiting example shown in FIG. 11, the width W2 of the connection surface 13 may be larger than the width W1 of the rising surface 11. In such a case, since a space for the connection surface 13 is easily secured, the chips are likely to curl stably and chip clogging is less likely to occur, and chip evacuation performance is excellent.

[0039] As described above, the upper surface 9 and the rising surface 11 may each be flat. When the upper surface 9 is flat, when the chip passes while curling on the upper surface 9, the connection surface 13, and the rising surface 11, the contact area of the chip on the upper surface 9 and the rising surface 11 can be reduced. Therefore, the upper surface 9 and the rising surface 11 are less likely to wear, and the durability of the insert 1 is high.

[0040] In a first cross section, the connection surface 13 may have an arc shape, and the radius of curvature R1 of the connection surface 13 may be larger than the width W1 of the rising surface 11. In such a case, since the chip is likely to curl gently, chip clogging is less likely to occur and chip evacuation performance is excellent.

[0041] When the connection surface 13 in the first cross section has an arc shape, the radius of curvature R1 of the connection surface 13 may be constant from the first side 17 toward the second side 19. In such a case, the chip is likely to have an elongated shape such as a spiral shape rather than a frustum of a cone shape as a whole. Therefore, chip evacuation performance is excellent.

[0042] Also, as in the non-limiting example shown in FIG. 11, in the first cross-section, the connection surface 13 may be in an elliptical arc shape, and the maximum value of the radius of curvature R1 of the connection surface 13 may be larger than the width W1 of the rising surface 11. In particular, in the non-limiting example shown in FIG. 11, it is vertically long in the vertical direction, in other words, it is in an elliptical arc shape with the vertical direction as the major axis. In such a case, the progress of the chips from the connection surface 13 to the rising surface 11 becomes smooth, so chip clogging is less likely to occur and chip discharge performance is excellent.

[0043] In the present disclosure, "constant" does not necessarily mean exactly the same value. It is a concept that allows for inevitable variations in manufacturing. Specifically, if the minimum value is 95% or more of the maximum value, it may be evaluated as constant. For example, when the width W2 of the connection surface 13 is constant from the first side 17 to the second side 19, the minimum value of the width W2 of the connection surface 13 may be 95 - 100% of the maximum value of the width W2 of the connection surface 13.

[0044] Examples of the material of the insert 1 may include cemented carbide and cermet. Examples of the composition of cemented carbide may include WC-Co, WC-TiC-Co, and WC-TiC-TaC-Co. Here, WC, TiC, and TaC may be hard particles, and Co may be a binder phase.

[0045] Also, the cermet may be a sintered composite material in which a metal is combined with a ceramic component. As an example of the cermet, a titanium compound mainly composed of titanium carbide (TiC) or titanium nitride (TiN) may be mentioned. However, the material of the insert 1 is not limited to the above composition.

[0046] The surface of the insert 1 may be coated with a film using a chemical vapor deposition (CVD) method or a physical vapor deposition (PVD) method. Examples of the composition of the film may include titanium carbide (TiC), titanium nitride (TiN), titanium carbonitride (TiCN), and alumina (Al 2 O 3 ) and the like.

[0047] <Cutting tool> Next, a cutting tool 101 according to a non-limiting aspect of the present disclosure will be described with reference to the drawings.

[0048] The cutting tool 101 may have a bar-shaped holder 105 extending from a first end 105a to a second end 105b, as in a non-limiting example shown in FIGS. 13 and 14. The holder 105 may have a pocket 103 (insert pocket) located on the side of the first end 105a. The cutting tool 101 may include the above-described insert 1 located in the pocket 103. In the cutting tool 101, the insert 1 may be mounted such that at least a part of the cutting edge 7 protrudes from the first end 105a of the holder 105.

[0049] The holder 105 may have an elongated bar shape. And one pocket 103 may be provided on the side of the first end 105a of the holder 105. The pocket 103 is a portion where the insert 1 is mounted and may be open to the end face on the side of the first end 105a in the holder 105.

[0050] As in a non-limiting example shown in FIG. 13, the insert 1 may be fixed to the holder 105 by a screw 107. For example, a screw hole may be provided in the holder 105, and the insert 1 may be constrained in the pocket 103 by inserting the screw 107 into the screw hole and pressing the screw 107 against the insert 1.

[0051] As the member of the holder 105, steel, cast iron, etc. may be used. In particular, when steel is used among these members, the toughness of the holder 105 is high.

[0052] <Method for manufacturing a machined product> Next, a method for manufacturing a machined product according to a non-limiting aspect of the present disclosure will be described with reference to the drawings.

[0053] The machined product 203 is produced by machining a workpiece 201. The method for manufacturing the machined product 203 in the embodiment includes the following steps. That is, (1) A step of rotating the workpiece 201; (2) A step of bringing the cutting tool 101 typified by the above embodiment into contact with the rotating workpiece 201; (3) A step of separating the cutting tool 101 from the workpiece 201; It includes.

[0054] More specifically, first, as shown in a non-limiting example in FIG. 15, the workpiece 201 may be rotated around the axis O3, and the cutting tool 101 may be relatively brought closer to the workpiece 201. Next, as shown in a non-limiting example in FIG. 16, at least a part of the cutting edge 7 of the cutting tool 101 may be brought into contact with the workpiece 201 to cut the workpiece 201. Then, as shown in a non-limiting example in FIG. 17, the cutting tool 101 may be relatively moved away from the workpiece 201.

[0055] As shown in a non-limiting example in FIG. 15, with the axis O3 fixed and the workpiece 201 rotated, the cutting tool 101 may be brought closer to the workpiece 201 by moving the cutting tool 101 in the Y1 direction.

[0056] Also, as shown in a non-limiting example in FIG. 16, the workpiece 201 may be cut by moving the cutting tool 101 in the Y2 direction in a state where at least a part of the portion used as the cutting edge 7 of the insert 1 is in contact with the rotating workpiece 201.

[0057] Also, as shown in a non-limiting example in FIG. 17, the cutting tool 101 may be moved away from the workpiece 201 by moving the cutting tool 101 in the Y3 direction with the workpiece 201 rotated.

[0058] In each step, by moving the cutting tool 101, the cutting tool 101 is brought into contact with the workpiece 201 or the cutting tool 101 is separated from the workpiece 201, but of course, it is not limited to such a form.

[0059] For example, in the step (1), the workpiece 201 may be brought closer to the cutting tool 101. Also, in the step (3), the workpiece 201 may be moved away from the cutting tool 101. When continuing the cutting process, the step of maintaining the workpiece 201 in a rotated state and bringing at least a part of the cutting edge 7 of the insert 1 into contact with different portions of the workpiece 201 may be repeated.

[0060] Typical examples of the material of the workpiece 201 may include hardened steel, carbon steel, alloy steel, stainless steel, cast iron, or non-ferrous metal, etc.

Explanation of Reference Numerals

[0061] 1 ··· Cutting insert (insert) 3 ··· First part 3a ··· Tip 3b ··· Rear end 5 ··· Second part 5a ··· Upper end face 7 ··· Cutting edge 9 ··· Upper face 11 ··· Rising face 13 ··· Connection face 15 ··· First corner 17 ··· First side 19 ··· Second side 21 ··· Side face 21a ··· First side face 21b ··· Second side face 21c ··· Corner side face 101 ··· Cutting tool 103 ··· Pocket 105 ··· Holder 107 ··· Screw 201 ··· Workpiece 203 ··· Machined part O1 ··· Central axis O2 ··· Virtual straight line L1 ··· Virtual extension line (of the upper face) L2 ··· Virtual extension line (of the rising face) θ ··· Angle at which the virtual extension lines intersect φ1 ··· Inclination angle of the connection face in top view φ2 ··· Inclination angle of the upper face W1 ··· Width of the rising surface W2 ··· Width of the connecting surface R1 ··· Radius of curvature

Claims

1. a rod-shaped first part extending along a central axis from a front end to a rear end; a second part protruding from the front end in a direction perpendicular to the central axis, and having: the second part having: a triangular shape when viewed from the front, a first corner protruding from the first part, a first side extending from the first corner toward the first part, an upper surface having a second side extending from the first corner toward the first part and located closer to the rear end than the first side, a cutting edge located at least partially on the first corner, the first side, and the second side, a rising surface located closer to the first part than the upper surface and inclined upward as it moves away from the upper surface, an upper end surface located closer to the first part than the rising surface, a connecting surface having a concave curved surface shape located between the upper surface and the rising surface and connected to the upper surface and the rising surface; a cutting insert, in a cross-section perpendicular to the upper end surface and including a bisector of the first corner, where virtual extension lines of the upper surface and the rising surface intersect at an acute angle.

2. The cutting insert according to claim 1, wherein the width of the rising surface increases as it moves away from the first side and approaches the second side.

3. The cutting insert according to claim 1, wherein the upper surface and the rising surface are each flat.

4. In the cross-section, the connecting surface has an elliptical arc shape, and The cutting insert according to claim 3, wherein a maximum value of a radius of curvature of the connecting surface is larger than a width of the rising surface.

5. a holder having a rod shape extending from a first end to a second end and having a pocket located at the first end, and a cutting insert according to any one of claims 1 to 4 located in the pocket. A cutting tool comprising.

6. a step of rotating a workpiece, a step of bringing the cutting tool according to claim 5 into contact with the rotating workpiece, and a step of separating the cutting tool from the workpiece. A method for manufacturing a machined product comprising.

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