Cutting inserts, and interchangeable rotary cutting tools

Abstract

This cutting insert (1) comprises a rake surface (2), a seating surface (3) facing the rake surface (2), a flank surface (4) connecting the rake surface (2) and the seating surface (3), and a cutting edge (5) formed on the intersecting ridge between the rake surface (2) and the flank surface (4). The cutting edge (5) is provided with a straight main cutting edge (5b), a corner edge (5a), and a wiper edge (5c) in that order. A concave portion (6) is formed at the end opposite to the end connected to the corner edge (5a) of the main cutting edge (5b). The wiper edge (5c) is formed in an arc shape and is connected tangentially to the corner edge (5a). When viewed from the side facing the rake surface (2), the extension line of the main cutting edge (5b) is L1. When L2 is the tangent of the wiper blade (5c) perpendicular to the extension line L1 of the main cutting blade (5b), and L3 is the tangent of the wiper blade (5c) passing through the edge P on the corner blade (5a) side of the wiper blade (5c), the angle θ formed by the tangent line L2 and the tangent line L3 is within the range of 0.010° ​​≤ θ ≤ 3.0°.

Description

Technology Field

[0001] The present invention relates to a cutting insert and a rotary cutting tool with an interchangeable cutting edge that rotates around an axis equipped with the cutting insert.

[0002] The present application claims priority based on Japanese Patent Application No. 2022-103176 filed in Japan on June 28, 2022, and incorporates the contents thereof herein by reference. Background Technology

[0003] Conventionally, in cutting tools used in processes where the surface roughness of the machined surface is required, such as intermediate finishing or finishing, there are cutting inserts equipped with a finishing edge (hereinafter also referred to as a wiper edge) at the tangent portion of the corner radius and the straight edge. Most of them have a straight-shaped wiper edge, but there are also cutting inserts equipped with an arc-shaped wiper edge. Prior art literature

[0004] Japanese Patent Publication No. 2005-103710 The problem to be solved

[0005] For example, Patent Document 1 discloses a shape having arc-shaped wiper blades on both sides of a corner blade. It discloses that the machining surface roughness is reduced by setting appropriate wiper blades to an arc shape for both the bottom cutting blade and the transverse cutting blade.

[0006] However, the invention described in Patent Document 1 focuses on the surface roughness of the machined surface in the feed direction and does not aim to reduce the step difference occurring in the radial direction. Furthermore, it assumes a large-diameter tool for which excessively high precision of the finished surface is not required. This point is evident from the fact that, in addition to the outer diameter of the rotary tool described in Patent Document 1 being φ50, Tables 1 and 2 of the same document disclose a relatively large value of surface roughness Rz of around 1.0 mm, even when the surface roughness of the machined surface is better. Additionally, Patent Document 1 describes that the workpiece is made of aluminum.

[0007] When the workpiece is made of aluminum, the insert shape is designed to improve cutting performance by making the rake angle positive and the cutting edge angle small. When cutting hard steel using such a cutting insert, there is a risk of chipping.

[0008] For this reason, the tool described in Patent Document 1 is used for rough processing of aluminum materials, and it is difficult to use it for finishing processing of steel materials. In particular, it is difficult to apply it to die molds, such as automobile engines or drive parts, most of which are made of chrome-molybdenum alloy steel, where high processing precision is required with a surface roughness of 5 μm or less on the finished surface.

[0009] The present invention is made in consideration of the above circumstances and has one of the objectives of providing a cutting insert capable of achieving a surface roughness of 5 μm or less of the machined surface, and a rotary cutting tool with an interchangeable cutting edge equipped with the cutting insert. means of solving the problem

[0010] [1] A cutting insert related to one aspect of the present invention comprises a rake surface, a seating surface opposite to the rake surface, a flank surface connecting the rake surface and the seating surface, and a cutting edge formed on an intersecting ridge between the rake surface and the flank surface. The cutting edge is provided with a straight main cutting edge (outer edge), a corner edge, and a wiper edge in that order. A concave portion is formed at the end opposite to the end of the main cutting edge (outer edge) that is connected to the corner edge. The wiper edge is formed in an arc shape and is connected tangentially to the corner edge. When viewed from the side opposite to the rake surface, the extension line of the main cutting edge (outer edge) is L1, the tangent line of the wiper edge is L2 which is perpendicular to the extension line L1 of the main cutting edge and also passes through the end point P of the wiper edge on the corner edge side. When the tangent of the wiper blade is L3, the angle θ formed by the tangent L2 and the tangent L3 is within the range of 0.010° ​​≤ θ ≤ 3.0°.

[0011] According to the above configuration, by making the wiper blade into an arc shape, in addition to the effect of reducing the roughness of the machined surface in the tool feed direction compared to the machined surface when the wiper blade is in a straight shape, the step difference between passes occurring in the tool radius direction is reduced, thereby increasing the flatness of the entire machined surface.

[0012] In addition, by making the angle θ formed by tangent line L2 and tangent line L3 within the range of 0.010° ​​≤ θ ≤ 3.0°, the surface roughness of the processed surface can be reduced. Furthermore, regarding the value of the angle θ, it is preferable to be within the range of 0.015° ≤ θ ≤ 2.0°, and more preferably within the range of 0.020° ≤ θ ≤ 1.0°. By doing so, the above effect obtained by the arc-shaped wiper blade can be further enhanced.

[0013] In addition, the tool feed direction is the direction in which the interchangeable cutting tool moves while rotating during cutting, and the tool radius direction is the direction perpendicular to the tool feed direction.

[0014] Here, if the angle θ formed by tangent L2 and tangent L3 is greater than 3.0°, the step difference between passes occurring in the tool radius direction increases, and the flatness of the machined surface deteriorates.

[0015] On the other hand, if the angle θ formed by tangent line L2 and tangent line L3 is less than 0.010°, the wiper blade becomes too close to a straight line, and the above effect obtained by the arc-shaped wiper blade cannot be sufficiently obtained.

[0016] [2] In the cutting insert described in [1], the wiper blade may be in the shape of a circle.

[0017] According to the above configuration, by forming the wiper blade into a circular arc shape, the cutting insert becomes easier to manufacture. As a result, a cutting insert with good precision can be manufactured.

[0018] [3] In the cutting insert described in [2], the arc radius R of the wiper blade may be 50 mm ≤ R < 200 mm.

[0019] When the arc radius R of the wiper blade is less than 50 mm, the amount of protrusion of the wiper blade relative to the machined surface is large, so it becomes difficult to reduce the surface roughness of the machined surface in the tool feed direction and to reduce the step difference between passes in the tool radius direction, and the surface roughness of the machined surface deteriorates.

[0020] On the other hand, when the arc radius R of the wiper blade is 200 mm or more, the shape of the wiper blade becomes closer to a straight line, so the effect of the arc shape is reduced.

[0021] Here, the arc radius R of the wiper blade is preferably 50 mm ≤ R ≤ 150 mm, and more preferably 100 mm ≤ R ≤ 150 mm.

[0022] [4] In a cutting insert described in any one of [1] to [3], the cutting edge is composed of the main cutting edge, the corner edge, the wiper edge, a straight internal cutting edge, and a second corner edge, the internal cutting edge is continuous at the end opposite to the end of the wiper edge connected to the corner edge, and the second corner edge is continuous at the end opposite to the end of the internal cutting edge connected to the wiper edge, and the angle α formed by the main cutting edge and the internal cutting edge may be within the range of 80° ≤ α < 90°.

[0023] If the angle α formed by the main cutting edge and the internal cutting edge is 80° or greater, the volume of the cutting insert can be sufficiently secured. As a result, the rigidity of the cutting insert can be improved.

[0024] [5] A rotary cutting tool with an interchangeable cutting edge related to one aspect of the present invention comprises a rake face, a seating surface opposite to the rake face, a flank surface connecting the rake face and the seating surface, and a cutting edge formed on an intersecting ridge between the rake face and the flank surface. The cutting edge is provided with a straight main cutting edge, a corner edge, and a wiper edge in that order. A concave portion is formed at the end opposite to the end connecting to the corner edge of the main cutting edge. The wiper edge is formed in an arc shape and is connected tangentially to the corner edge. When viewed from a direction opposite to the rake face, L1 is the extension of the main cutting edge, L2 is the tangent of the wiper edge perpendicular to the extension line L1, and L3 is the tangent of the wiper edge passing through the edge P on the corner edge side of the wiper edge. The cutting insert, formed by the angle θ of L3 within the range of 0.010° ​​≤ θ ≤ 3.0°, is mounted on a tool body rotatable around the axis of rotation as an interchangeable cutting tool, characterized in that the lowest point of the cutting insert in the direction along the axis of rotation is located on the wiper blade.

[0025] The lowest point is the point located at the leading edge in the direction of the rotational axis on the cutting insert mounted on the tool body. By having the lowest point of the tool on the wiper blade rather than on the corner blade, the present invention allows the wiper blade to continue to be applied to the workpiece even if the interchangeable rotary cutting tool vibrates or the tool itself bends under cutting conditions where a high load is applied. This allows the surface roughness of the machined surface to be reduced.

[0026] [6] In the rotary cutting tool with interchangeable cutting edges described in [5], when viewed from the direction opposite to the rake face, the wiper blade of the cutting insert may be in the shape of a round arc.

[0027] [7] In the rotary cutting tool with interchangeable cutting edge described in [6], the arc radius R of the wiper blade of the cutting insert may be 50 mm ≤ R < 200 mm. Effects of the invention

[0028] According to the present invention, a cutting insert capable of achieving a surface roughness of 5 μm or less of the machined surface, and a rotary cutting tool with an interchangeable cutting edge equipped with the cutting insert can be provided. Brief explanation of the drawing

[0029] FIG. 1 is a perspective view showing a cutting insert of the present embodiment. FIG. 2 is a plan view showing a cutting insert of the present embodiment. FIG. 3 is a short-side view showing a cutting insert of the present embodiment. FIG. 4 is a long-side view showing a cutting insert of the present embodiment. Figure 5 is a schematic diagram of the area enclosed by the dotted line shown in Figure 2. FIG. 6 is a perspective view of an interchangeable rotary cutting tool showing the cutting insert of the present embodiment mounted on the tool body. FIG. 7 is a perspective view of a tool body on which a cutting insert of the present embodiment can be mounted. FIG. 8 is a drawing illustrating the tool feed direction and tool radius direction of an interchangeable cutting tool. Specific details for implementing the invention

[0030] <Embodiment>

[0031] Hereinafter, the cutting insert and the interchangeable cutting tool of the present invention will be described with reference to FIGS. 1 to 5. In addition, the drawings used to describe the embodiments may show parts that are major components enlarged, compressed, or excerpted to make it easier to understand the features of the present invention.

[0032] (Cutting insert)

[0033] FIG. 1 is a perspective view showing a cutting insert of the present embodiment. FIG. 2 is a plan view showing a cutting insert of the present embodiment. FIG. 3 is a short-side side view showing a cutting insert of the present embodiment. FIG. 4 is a long-side side view showing a cutting insert of the present embodiment.

[0034] The cutting insert (1) of this embodiment is polygonal when viewed from the direction along the centerline (CO) extending in the thickness direction.

[0035] In the following description, the direction along the centerline (CO) may be simply referred to as the thickness direction. The direction perpendicular to the centerline (CO) may be simply referred to as the width direction. Likewise, the circumferential direction around the axis centered on the centerline (CO) may be simply referred to as the circumferential direction.

[0036] Also, in the following description, the tool feed direction is the direction in which the interchangeable cutting tool moves while rotating during the cutting of the workpiece, and the tool radius direction is a direction perpendicular to the tool feed direction. Here, FIG. 8 is a diagram for explaining the tool feed direction (A) and the tool radius direction (B). For example, the tool feed direction (A) for the workpiece (8) shown in FIG. 8 is a direction along the X direction, and the tool radius direction (B) is a direction along the Y direction. The interchangeable rotary cutting tool (11) contacts the workpiece (8) from the Z direction, which is orthogonal to the X direction and the Y direction.

[0037] As shown in FIGS. 1 to 4, the cutting insert (1) has an upper surface that is a rake surface (2), a lower surface that is opposite to the rake surface (2) that is a seating surface (3), and a side surface that connects the rake surface (2) and the seating surface (3) that is a flank surface (4). The seating surface (3) is smaller in size than the rake surface (2) when viewed from a plane and is contained within the projection area in the centerline direction (thickness direction) of the rake surface (2).

[0038] A cutting edge (5) is formed at the intersection of the rake face (2) and the flank face (4).

[0039] The cutting blade (5) comprises a corner blade (first corner blade) (5a) located at the corner portion of the rake surface (2), a straight main cutting blade (outer blade) (5b) continuous to one end of the corner blade (5a), an arc-shaped wiper blade (5c) continuous to the other end of the corner blade (5a), a straight inner cutting blade (5d) continuous to the end opposite to the end connected to the corner blade (5a) of the wiper blade (5c), and a second corner blade (5e) continuous to the end opposite to the end connected to the wiper blade (5c) of the inner cutting blade (5d).

[0040] The second corner blade (5e) is located in a different corner (obtuse corner) among the multiple corner portions of the rake face (2), which is different from the corner portion where the first corner blade (5a) is located. The radius of curvature of the second corner blade (5e) is smaller than the radius of curvature of the first corner blade (5a).

[0041] The main cutting blade (5b), corner blade (5a), wiper blade (5c), inner cutting blade (5d), and second corner blade (5e) are arranged in this order in the right direction (clockwise) when viewed from the plane of the rake surface (2), and are shaped like rectangular plates that are 180° rotationally symmetric with respect to the centerline (CO). Also, the corner blade (5a) and the wiper blade (5c) are smoothly connected.

[0042] Depending on the processing method or processing shape, each cutting edge may or may not function as a cutting edge. For example, when processing a vertical wall, the main cutting edge (5b) is mainly used.

[0043] The wiper blade (5c) can be used for finishing the bottom surface, and can smooth out the unevenness of the bottom surface to reduce the surface roughness of the processed surface.

[0044] Corner blades (5a) can be widely used in corners or on shapes with many irregularities when processing wall sections.

[0045] The internal cutting edge (5d) acts as a cutting edge in inclined cutting processes, etc.

[0046] As shown in FIG. 2, the angle α formed by the main cutting edge (5b) formed on the long side of the rake face (2) and the inner cutting edge (5d) formed on the short side is an acute angle. The angle α formed by the main cutting edge (5b) and the inner cutting edge (5d), which are in a straight line with each other, is, for example, within the range of 80° ≤ α < 90°. If the angle α formed by the main cutting edge (5b) and the inner cutting edge (5d) is 80° or greater, the volume of the cutting insert (1) can be sufficiently secured. As a result, the rigidity of the cutting insert (1) can be improved.

[0047] In addition, the value of α is preferably within the range of 83° ≤ α ≤ 89°, and more preferably within the range of 85° ≤ α ≤ 88°. This allows the rigidity of the cutting insert (1) to be further improved.

[0048] As shown in FIGS. 1 and 2, the cutting insert (1) has a concave portion (6) formed at the end opposite to the end connected to the corner edge (5a) of the main cutting edge (5b). By forming this concave portion (6), for example, when reciprocating machining is performed, the end (6a) (Fig. 2) of the concave portion (6) on the side of the main cutting edge (5b) acts as a cutting edge.

[0049] Figure 5 is a schematic diagram of the area enclosed by the dotted line shown in Figure 2.

[0050] In this embodiment, by making the wiper blade (5c) of the main cutting blade (5b) into an arc shape, in addition to the effect of reducing the roughness of the machined surface in the tool feed direction (A) (X direction) compared to machining when the wiper blade is in a straight shape, the step difference between passes occurring in the tool radius direction (B) (Y direction) is reduced, thereby increasing the flatness of the entire machined surface.

[0051] Here, when the extension line of the main cutting edge (5b) is L1, the tangent line of the wiper blade (5c) perpendicular to the extension line L1 is L2, and the tangent line of the wiper blade (5c) passing through the edge P on the corner edge (5a) side of the wiper blade (5c) is L3, the angle θ formed by the tangent line L2 and the tangent line L3 is included within the range of 0.010° ​​≤ θ ≤ 3.0°. By making the angle θ formed by the tangent line L2 and the tangent line L3 within the above range, the surface roughness of the machined surface can be reduced.

[0052] In short, by making the curvature of the wiper blade (5c) close to the curvature of the corner blade (5a), it is difficult for a step to occur between the wiper blade (5c) and the corner blade (5a), and thus it is difficult for an angular shape to be formed at the boundary point P (the above disadvantage P) between the wiper blade (5c) and the corner blade (5a).

[0053] As a result, cutter marks become less noticeable, making it possible to reduce the surface roughness of the machined surface.

[0054] Here, if the angle θ formed by tangent L2 and tangent L3 is greater than 3.0°, the amount of protrusion (protrusion amount L) of the wiper blade (5c) relative to the processing surface is large, so the step difference between passes in the tool radius direction (B) increases, and the desired surface roughness of the processing surface cannot be obtained. The protrusion amount L may be the distance from the boundary point P between the wiper blade (5c) and the corner blade (5a) to the processing surface (tangential L2 in this embodiment).

[0055] On the other hand, if the angle θ formed by tangent line L2 and tangent line L3 is less than 0.010°, the curved wiper blade (5c) becomes too close to a straight line, and the effect of the arc-shaped wiper blade (5c) cannot be fully obtained. If the wiper blade (5c) becomes close to a straight line, the effect of the arc shape is reduced.

[0056] Therefore, by setting the angle θ formed by tangent L2 and tangent L3 within the above range, the effect of the arc-shaped wiper blade (5c) can be fully obtained, which reduces the roughness of the machined surface in the tool feed direction (A) (X direction) and reduces the step difference between passes in the tool radius direction (B) (Y direction), thereby increasing the flatness of the entire machined surface.

[0057] In addition, the value of θ is preferably within the range of 0.015° ≤ θ ≤ 2.0°, and more preferably within the range of 0.020° ≤ θ ≤ 1.0°. By doing so, the effect obtained by the arc-shaped wiper blade (5c) can be further enhanced.

[0058] In addition, the wiper blade (5c) forming the arc shape may be in the shape of an arc, and may be in a curved shape such as an ellipse, but it is preferable that it be in the shape of a round arc. By forming the wiper blade (5c) in the shape of a round arc, the manufacturing of the cutting insert (1) becomes easier. As a result, a cutting insert (1) with good dimensional accuracy can be obtained, and the precision of the machined surface is also improved.

[0059] Here, in the case of a wiper blade (5c) forming a circular arc shape, the arc radius (radius of curvature) R is preferably within the range of 50 mm ≤ R < 200 mm. Here, the arc radius R of the wiper blade is preferably 50 mm ≤ R ≤ 150 mm, and more preferably 100 mm ≤ R ≤ 150 mm.

[0060] In this way, by making the arc radius R of the wiper blade (5c) within the range of 50 mm ≤ R < 200 mm, when the cutting insert (1) is mounted on the tool body (10) described later and used as a rotary cutting tool (11) with an interchangeable cutting edge, the effect of stabilizing the surface roughness of the machined surface is obtained by reducing the roughness of the machined surface in the tool feed direction (A) (X direction) and reducing the step difference between passes occurring in the tool radius direction (B) (Y direction), thereby increasing the flatness of the entire machined surface.

[0061] Also, as shown in FIG. 5, the width W of the wiper blade (5c) of this embodiment is approximately 1.5 mm, but can be appropriately changed depending on the size of the cutting insert (1). Additionally, by forming the lowest point Q on the wiper blade (5c), the surface roughness of the machined surface can be reduced. The lowest point Q is the point located at the tip in the direction of the rotation axis of the cutting insert mounted on the tool body.

[0062] (Interchangeable rotary cutting tool)

[0063] FIG. 6 is a perspective view showing a cutting tool (11) with an interchangeable cutting edge, showing the cutting insert (1) of the present embodiment mounted on the tool body (10). FIG. 7 is a perspective view showing a tool body (10) on which the cutting insert (1) of the present embodiment can be mounted.

[0064] As shown in FIG. 6, the interchangeable cutting tool (11) has a tool body (10) and a plurality of cutting inserts (1). In this embodiment, for example, it has four cutting inserts (1). The interchangeable cutting tool (11) performs cutting by rotating the tool body (10) in a rotational direction (TD) around a rotation axis (JO).

[0065] As shown in FIG. 7, in this embodiment, four insert mounting seats (33) are formed at the tip of the tool body (10) in correspondence with the number of cutting inserts (1) mounted thereon. The number of insert mounting seats (33) increases or decreases depending on the tool diameter of the tip-exchangeable rotary cutting tool (11). Therefore, when the tool diameter is large, the number of insert mounting seats (33) increases, and conversely, when the tool diameter is small, the number of insert mounting seats (33) decreases.

[0066] The insert mounting sheet (33) has a mounting sheet bottom surface (33a) and a pair of mounting sheet wall surfaces (33b).

[0067] The mounting seat bottom surface (33a) forms a rectangular shape with an area approximately equal to the seating surface (3) of the cutting insert (1) and faces the rotational direction (TD) of the tool body (10). A pair of mounting seat wall surfaces (33b) are surfaces that extend from two sides of the mounting seat bottom surface (33a) toward the rotational direction (TD).

[0068] The bottom surface (33a) of the mounting seat contacts the seating surface (3) of the cutting insert (1).

[0069] Of the pair of mounting sheet walls (33b), the mounting sheet wall (33b) along the axial direction contacts the side along the long side of the cutting insert (1). Of the pair of mounting sheet walls (33b), the mounting sheet wall (33b) along the radial direction contacts the side along the short side of the cutting insert (1). That is, the pair of mounting sheet walls (33b) contact these in opposition to the flank surface of the cutting insert (1).

[0070] A screw hole (33c) is formed approximately in the center of the bottom surface (33a) of the mounting sheet. The screw hole (33c) is a hole that communicates with the mounting hole (7) formed in the center of the cutting insert (1). A mounting screw (12) for mounting the cutting insert (1) is inserted into the screw hole (33c).

[0071] A cutting insert (1) is mounted to a tool body (10) by a mounting screw (12) inserted into a mounting hole (7) formed in its center being fastened to a screw hole (33c) formed in the center of the mounting seat bottom surface (33a) of the tool body (10). In this way, a plurality of cutting inserts (1) are each detachably mounted to each insert mounting seat (33) of the tool body (10) using a mounting screw (12).

[0072] In the cutting tool (11) of the present embodiment, all four cutting inserts mounted on the tool body (10) have arc-shaped wiper blades (5c). By setting the arc radius of the wiper blades (5c) to within the above range, it is possible to make the surface roughness of the machined surface 5 μm or less, and the effect of reducing the surface roughness of the machined surface in the tool feed direction (A) (X direction) and reducing the step difference between passes occurring in the tool radius direction (B) (Y direction) is obtained, thereby increasing the flatness of the entire machined surface. As a result, the surface roughness of the machined surface is stabilized, and a finished surface with high machining precision can be obtained.

[0073] As a result, the cutting edge interchangeable rotary cutting tool (11) of this embodiment can be used for machining die molds made of hard chrome-molybdenum alloy steel, such as automobile engines or drive parts, where high machining precision is required.

[0074] In the cutting tool (11) of the present embodiment, the lowest point Q of the cutting insert (1) in the direction along the rotation axis (JO) is located on the wiper blade (5c). By providing the lowest point Q on the wiper blade (5c), the wiper blade (5c) can be continuously applied to the workpiece (8) even if the cutting tool (11) vibrates or the cutting tool (11) itself bends under cutting conditions where a high load is applied. This allows the surface roughness of the machined surface to be reduced.

[0075] Examples

[0076] To confirm the effects of the present invention, a cutting test was performed using the cutting inserts shown in Table 1 (Examples 1 to 3, Comparative Examples 1 and 2).

[0077] In addition, the processing conditions are as follows.

[0078] (Processing conditions)

[0079] · Workpiece: Chromium-molybdenum alloy steel (46.5HRC)

[0080] · Tool diameter: φ25 mm

[0081] · Cutting speed Vc: 275 m / min

[0082] · Feed rate per tooth fz: 0.057 mm / t

[0083] · Axial depth of cut ap: 0.04 mm

[0084] · Diameter depth of cut ae: 20 mm

[0085] · Protrusion length OH: 175 mm

[0086] · Coolant: Air

[0087]

[0088] The results of the cutting test described above are shown in Table 2.

[0089]

[0090] From Table 2, in Examples 1 to 3, the surface roughness of the processed surface achieved the target value of 5 μm or less. On the other hand, in Comparative Examples 1 and 2, the surface roughness of the processed surface was greater than 5 μm compared to Examples 1 to 3.

[0091] From the above, it was shown that good results were obtained with the cutting inserts of Examples 1 to 3.

[0092] Furthermore, within the scope that does not deviate from the spirit of the present invention, each component (component) described in the aforementioned embodiments and provisos may be combined, and additional, omission, substitution, or other modification of the components may be made. In addition, the present invention is not limited by the aforementioned embodiments, but is limited only by the scope of the patent claims.

[0093] Industrial applicability

[0094] According to the present invention, a cutting insert capable of achieving a surface roughness of 5 μm or less of the machined surface, and a rotary cutting tool with an interchangeable cutting edge equipped with the cutting insert can be provided. Explanation of the symbols

[0095] 1 : Cutting insert 2 : Lake face 3 : Seat surface 4 : Plank side 5 : Cutting edge 5a : Corner edge 5b : Main cutting edge 5c : Wiper blade 5d: Internal cutting edge 5e : 2nd corner edge 6 : Concave part 10: Tool body 11: Interchangeable rotary cutting tool JO: Rotation axis L1 : Extension line L2, L3: Tangent P: Boundary point (disadvantage) Q: Tool lowest score (lowest score) L: Protrusion amount of the wiper blade (5c) relative to the processed surface R: Arc radius α: The angle formed by the main cutting edge (5b) and the inner cutting edge (5d). θ: The angle formed by tangent line L2 and tangent line L3

Claims

Claim 1 A cutting insert having a polygonal shape centered on a centerline, comprising a rake face, a seating surface opposite to the rake face, a flank surface connecting the rake face and the seating surface, and a cutting edge formed on an intersecting ridge between the rake face and the flank surface, wherein the cutting edge comprises a straight main cutting edge, a corner edge, and a wiper edge in that order, wherein a concave portion is formed on the end opposite to the end connecting to the corner edge of the main cutting edge, recessed toward the centerline, and wherein the wiper edge is formed in an arc shape and connected tangentially to the corner edge, and when viewed from the side opposite to the rake face, when the extension line of the main cutting edge is L1, the tangent line of the wiper edge perpendicular to the extension line L1 is L2, and the tangent line of the wiper edge passing through the indentation P on the corner edge side of the wiper edge is L3, the tangent line L2 and the A cutting insert characterized in that the angle θ formed by the tangent line L3 is within the range of 0.010° ​​≤ θ ≤ 3.0°. Claim 2 A cutting insert according to claim 1, characterized in that, when viewed from the side opposite the rake surface, the wiper blade has a circular arc shape. Claim 3 A cutting insert according to claim 2, characterized in that the arc radius R of the wiper blade is within the range of 50 mm ≤ R < 200 mm. Claim 4 A cutting insert according to claim 1 or 2, wherein the cutting edge comprises the main cutting edge, the corner edge, the wiper edge, a straight internal cutting edge, and a second corner edge, wherein the internal cutting edge is continuous at the end opposite to the end of the wiper edge connected to the corner edge, and the second corner edge is continuous at the end opposite to the end of the internal cutting edge connected to the wiper edge, and the angle α formed by the main cutting edge and the internal cutting edge is within the range of 80° ≤ α < 90°. Claim 5 A rotary cutting tool with an interchangeable cutting edge, wherein a cutting insert having a polygonal shape centered on a centerline is mounted on a tool body rotatable around the axis of a rotation axis, wherein the cutting insert comprises a rake face, a seating surface opposite to the rake face, a flank surface connecting the rake face and the seating surface, and a cutting edge formed on an intersecting ridge between the rake face and the flank surface, wherein the cutting edge comprises a straight main cutting edge, a corner edge, and a wiper edge in that order, wherein a concave portion is formed on the end opposite to the end connecting to the corner edge of the main cutting edge, which is recessed toward the centerline, and wherein the wiper edge is formed in an arc shape and is connected tangentially to the corner edge, and when viewed from a direction opposite to the rake face, the extension line of the main cutting edge is L1, the tangent line of the wiper edge perpendicular to the extension line L1 is L2, and the disadvantage P of the wiper edge on the corner edge side A rotary cutting tool with an interchangeable cutting edge, characterized in that when the tangent of the passing wiper blade is L3, the angle θ formed by the tangent L2 and the tangent L3 is within the range of 0.010° ​​≤ θ ≤ 3.0°, and the lowest point of the cutting insert in the direction along the rotation axis is located on the wiper blade. Claim 6 A rotary cutting tool with an interchangeable cutting edge, characterized in that, in claim 5, when viewed from a direction opposite to the rake face, the wiper blade of the cutting insert has a circular arc shape. Claim 7 A rotary cutting tool with an interchangeable cutting edge, characterized in that, in claim 6, the arc radius R of the wiper blade of the cutting insert is 50 mm ≤ R < 200 mm.

Images