Cutting insert

Abstract

To provide a cutting insert capable of restraining cutting resistance while securing chip treatment performance.SOLUTION: A cutting insert 1 includes: an insert body 2; a main surface 3A and a reverse surface 3B of a polygonal shape in plan view; an outer peripheral surface 4 connecting peripheral edges of the main surface 3A and the reverse surface 3B to each other; and a cutting edge 5 arranged in a crossing ridge part between the main surface 3A and the outer peripheral surface 4. The cutting edge 5 has a corner blade 5a positioned in a corner part 3c of the main surface 3A. The corner part 3c of the main surface 3A includes: a rake face 21 arranged on an inner side of a plate thickness direction relative to the main surface 3A; a projection tip part 23 arranged on an inner side of an insert radial direction orthogonal to the plate thickness direction from the corner blade 5a and projecting from the rake face 21 in the plate thickness direction; a first inclined plane 24 inclined from the projection tip part 23 to the inner side of the plate thickness direction toward the inner side of the insert radial direction; and a second inclined plane 25 inclined from the first inclined plane 24 to the outer side of the plate thickness direction toward the inner side of the insert radial direction.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a cutting insert.

Background Art

[0002] Conventionally, as a cutting insert (replaceable cutting tip) for cutting operations mounted on a tool body of a replaceable tip tool, for example, the one described in Patent Document 1 below is known. The cutting insert of Patent Document 1 has a cutting edge, a protrusion extending toward the central portion of the cutting insert, and a wall portion formed at the end of the protrusion. With such a configuration, it is intended to exhibit good chip disposal performance and reduce cutting resistance.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the cutting insert as described above, the thickness of the cutting chips varies depending on the cutting depth, and depending on the cutting conditions, the cutting chips may hit the wall portion forcefully, increasing the cutting resistance.

[0005] In view of the above circumstances, one object of the present invention is to provide a cutting insert that can suppress cutting resistance while ensuring chip disposal performance.

Means for Solving the Problems

[0006] One embodiment of the cutting insert of the present invention comprises a polygonal plate-shaped insert body, a main surface and a back surface provided on the insert body and having a polygonal shape in plan view, facing opposite directions from each other in the thickness direction of the insert body, an outer peripheral surface connecting the periphery of the main surface and the back surface, and a cutting edge provided on the intersecting ridge line of the main surface and the outer peripheral surface, wherein the cutting edge has a corner blade located at the corner of the main surface, and the corner of the main surface has a rake face provided on the inside of the main surface in the thickness direction, a projection tip provided on the inside of the insert diameter direction perpendicular to the thickness direction from the corner blade and projecting from the rake face in the thickness direction, a first inclined surface inclined in the thickness direction toward the inside of the insert diameter direction toward the inside of the projection tip, and a second inclined surface inclined outward in the thickness direction toward the inside of the insert diameter direction toward the inside of the first inclined surface.

[0007] According to one embodiment of the cutting insert of the present invention, a rake face, a projection tip, a first inclined surface, and a second inclined surface are sequentially formed on the corner of the main surface, extending inward from the corner cutting edge in the insert radial direction. Chips generated by cutting the workpiece with the corner cutting edge come into contact with at least one of the projection tip, the first inclined surface, and the second inclined surface, depending on the depth of cut. In machining with a small depth of cut and a low feed rate, the chips come into contact with the projection tip, which is close to the corner cutting edge. Upon contact with the projection tip, the chips curl, and the chips are well processed. Furthermore, as the depth of cut increases, the contact position of the chips moves from the projection tip side to the first inclined surface side. Since the first inclined surface is inclined inward in the plate thickness direction toward the inside in the insert radial direction, the contact resistance when the chips come into contact with the first inclined surface is suppressed. This suppresses cutting resistance. As the depth of cut increases further, the contact position of the chips moves from the first inclined surface side to the second inclined surface side. The second inclined surface is inclined inward in the radial direction of the insert and outward in the thickness direction of the plate. As the depth of cut increases, the chips become thicker and more robust. By bringing the thick chips into contact with the second inclined surface, the chips can be reliably guided away from the main surface towards the outward direction of the plate thickness. In this way, it is possible to suppress cutting resistance while ensuring chip removal performance according to the depth of cut.

[0008] In the above-described cutting insert, the first inclined surface may be formed parallel to the back surface in a cross-sectional view perpendicular to the angle bisector of the corner portion at the corner cutting edge.

[0009] In this case, by making the first inclined surface a flat surface parallel to the back surface, the area of ​​the first inclined surface that contacts the chips at the same position in the thickness direction can be increased compared to the case where the first inclined surface is a curved surface that protrudes outward in the thickness direction. Therefore, the function of receiving chips can be improved.

[0010] In the above-described cutting insert, the first inclined surface may be inclined inward in the thickness direction from the tip of the projection towards the inside in the diameter direction of the insert.

[0011] In this case, the first inclined surface smoothly continues from the top of the projection tip, allowing for smooth guidance of the chips.

[0012] In the above-described cutting insert, the angle θ1 formed by the cutting edge located on one side of the angle bisector and the cutting edge located on the other side of the angle bisector is such that the angle range θ2 in which the tip of the projection spans both sides of the angle bisector is 0.35 ≤ θ2 / θ1 ≤ 0.85.

[0013] By setting the angular range θ2 relative to angle θ1 within the above-mentioned range, it is possible to improve chip handling while suppressing cutting resistance, thereby providing a cutting insert with an excellent balance of these performance characteristics.

[0014] In the above-described cutting insert, the top of the projection tip may be lower than the cutting edge of the corner blade.

[0015] In this case, if the depth of cut is small, the chips generated by cutting the workpiece with the corner blade can be reliably brought into contact with the tip of the projection and curled.

[0016] In the above-described cutting insert, the cutting edge has a straight blade that extends inclined inward in the thickness direction as it moves away from the corner blade at the corner of the main surface at the intersecting ridge line, and the top of the projection tip may protrude in a direction intersecting the extension direction in which the straight blade extends.

[0017] In this case, when the depth of cut is large and the workpiece is cut not only with the corner cutting edge but also with the straight cutting edge, the cutting resistance of the straight cutting edge can be suppressed by making it lower than the top of the tip of the projection.

[0018] In the above cutting insert, the cutting edge has a straight edge that extends obliquely inward in the plate thickness direction as it separates from the corner edge at the corner of the main surface in the intersecting ridge line portion. The first inclination angle θ3 at which the first inclined surface is inclined with respect to the surface orthogonal to the plate thickness direction may be such that θ3 > θ4 with respect to the second inclination angle θ4 at which the straight edge is inclined with respect to the surface orthogonal to the plate thickness direction.

[0019] In this case, as it separates from the corner edge, the straight edge becomes lower than the first inclined surface. Thereby, when cutting the workpiece not only with the corner edge but also with the straight edge, by making the straight edge lower than the first inclined surface, it is possible to suppress an increase in the cutting resistance at the straight edge.

[0020] In the above cutting insert, in the direction in which the bisector of the corner portion extends, a first distance L1 from the cutting edge of the corner edge to the intersection of the rake face and the tip of the projection, and a second distance L2 from the cutting edge of the corner edge to the intersection of the first inclined surface and the second inclined surface, may satisfy 0.10 ≦ L1 / L2 ≦ 0.75.

[0021] In this case, according to the depth of cut, the position where the chip contacts the tip of the projection, the first inclined surface, and the second inclined surface can be appropriately shifted. Furthermore, by setting the first distance L1 and the second distance L2 so as to satisfy the above relationship, it is possible to enhance the chip disposability within the range of the assumed depth of cut.

Advantages of the Invention

[0022] According to the cutting insert of one aspect of the present invention, it is possible to suppress the cutting resistance while ensuring the chip disposal performance.

Brief Description of the Drawings

[0023] [Figure 1] It is a perspective view showing a cutting insert of an embodiment of the present invention. [Figure 2] It is a plan view of a cutting insert of an embodiment of the present invention. <000,0092><000,009,3>Side view of a cutting insert according to an embodiment of the present invention. [Figure 4] Expanded plan view of a corner portion of a cutting insert according to an embodiment of the present invention. [Figure 5] Expanded perspective view of a corner portion of a cutting insert according to an embodiment of the present invention. [Figure 6] Cross-sectional view taken along the line A-A of FIG. 4. [Figure 7] Cross-sectional view along the bisector of a corner portion of a cutting insert according to an embodiment of the present invention, and cross-sectional view taken along the line B-B of FIG. 4. [Figure 8] Expanded side view of a corner portion of a cutting insert according to an embodiment of the present invention.

Mode for Carrying Out the Invention

[0024] Hereinafter, a cutting insert 1, which is an example of a cutting insert according to an embodiment of the present invention, will be described with reference to the drawings.

[0025] FIG. 1 is a perspective view showing the cutting insert 1 of the present embodiment. FIG. 2 is a plan view of the cutting insert 1 of the present embodiment. FIG. 3 is a side view of the cutting insert 1 of the present embodiment. Hereinafter, the cutting insert 1 according to the embodiment of the present invention will be described with reference to the drawings. The cutting insert 1 of the present embodiment is mounted on a tool body (holder) of a tip-exchangeable tool, not shown, and performs cutting on a workpiece made of a metal material such as steel.

[0026] 〔Schematic Configuration of Cutting Insert〕 As shown in FIGS. 1 to 3, the cutting insert 1 has a polygonal plate-shaped insert body 2. The insert body 2 is provided in a polygonal plate shape, specifically a quadrangular plate shape, and more specifically a rhombic plate shape, made of a hard material such as cemented carbide. A mounting hole 6 having a circular cross section is provided at the central portion of the insert body 2. The mounting hole 6 is provided so as to penetrate the insert body 2 in its plate thickness direction. The insert body 2 in the present embodiment is provided in a shape that is rotationally symmetric by 180° around the center line of the mounting hole 6.

[0027] The insert body 2 has a main surface 3A, a back surface 3B, an outer peripheral surface 4, and a cutting edge 5. The main surface 3A and the back surface 3B face opposite each other in the thickness direction on the insert body 2. When viewed from the thickness direction, the main surface 3A and the back surface 3B have a polygonal shape in plan view. The outer peripheral surface 4 connects the periphery of the main surface 3A and the back surface 3B.

[0028] In this embodiment, the main surface 3A and the back surface 3B have similar configurations, except that they are located on opposite sides of each other in the thickness direction. In cutting operations using the cutting insert 1, cutting is performed by a cutting edge 5 provided between either the main surface 3A or the back surface 3B and the outer peripheral surface 4, while the other surface functions as a seating surface for the tool body (not shown).

[0029] [Cutting edge configuration] The cutting edge 5 is provided at the acute corner 3c of the rhombus formed by the polygonal main surface 3A and the back surface 3B. In this embodiment, the cutting edge 5 is provided on both the main surface 3A side and the back surface 3B side. The cutting edge 5 on the main surface 3A side is provided at the intersecting ridge line between the main surface 3A and the outer peripheral surface 4. The cutting edge 5 on the back surface 3B side is provided at the intersecting ridge line between the back surface 3B and the outer peripheral surface 4. The cutting insert 1 in this embodiment is a double-sided insert with a symmetrical shape that is inverted on both sides. Therefore, the cutting edges 5 are provided at the intersecting ridges between the main surface 3A and the back surface 3B and the outer peripheral surface 4. However, the cutting insert 1 may also be a single-sided insert in which the cutting edges 5 are provided only at the intersecting ridges between the main surface 3A and the outer peripheral surface 4.

[0030] In the following description, the main surface 3A will be described primarily, and the description of the back surface 3B, which has a similar configuration to the main surface 3A, will be omitted. Similarly, in the following description, only the cutting edge 5 provided at the intersection of the main surface 3A and the outer peripheral surface 4 will be described, and the description of the cutting edge 5 provided at the intersection of the back surface 3B and the outer peripheral surface 4 will be omitted.

[0031] The cutting edge 5 has a corner blade 5a located at the corner 3c of the main surface 3A (or back surface 3B) and straight blades 5b located on each side of the main surface 3A (or back surface 3B). The straight blades 5b extend inclined inward in the thickness direction (towards the back surface 3B) as they move away from the corner blade 5a at the corner 3c of the main surface 3A at the intersecting ridge.

[0032] [Circuit breaker configuration] Figure 4 is an enlarged plan view of the corner 3c of the cutting insert 1. Figure 5 is an enlarged perspective view of the corner 3c of the cutting insert 1. Figure 6 is a cross-sectional view taken along the arrow AA in Figure 4. Figure 7 is an enlarged side view of the corner 3c of the cutting insert 1. Figure 8 is a cross-sectional view along the bisector of the corner 3c of the cutting insert 1, and is a cross-sectional view taken along the arrow BB in Figure 4. As shown in Figures 4 to 6, a recess 20 is provided at the corner 3c of the main surface 3A. The recess 20 is provided on the main surface 3A between the cutting edge 5 and the ridge 30. The recess 20 is recessed on the back surface 3B side, which is the inner side in the thickness direction relative to the main surface 3A. The recess 20 extends along the cutting length direction of the corner edge 5a and the straight edge 5b of the cutting edge 5. The recess 20 is located in a region adjacent to the cutting edge 5 and has an inclined surface 20a that extends along the cutting edge 5 over its entire length. The inclined surface 20a inclines towards the back surface 3B side as it moves inward in the insert diameter direction from the cutting edge 5.

[0033] As shown in Figure 7, a rake face 21 is provided on the inside of the insert in the radial direction relative to the corner blade 5a. The rake face 21 is perpendicular to the thickness direction of the insert body 2. The rake face 21 is recessed on the inside (back surface 3B side) in the thickness direction relative to the cutting edge of the cutting blade 5.

[0034] As shown in Figures 1 to 5, the ridge 30 is positioned spaced inward from the cutting edge 5 in the insert radial direction. The ridge 30 protrudes outward in the insert radial direction when viewed from the plate thickness direction. When viewed from the plate thickness direction, the width dimension of the ridge 30 in the direction in which the bisector S of the corner 3c (see Figure 4) extends, and in the direction perpendicular to the plate thickness direction, gradually decreases outward in the insert radial direction. The top surface 31 of the ridge 30 is located on the back surface 3B side of the main surface 3A in the plate thickness direction. The top surface 31 is located parallel to the main surface 3A. The ridge 30 is embankment-shaped and has a pair of lateral inclined surfaces 32. The pair of lateral inclined surfaces 32 are located on both sides of the bisector S of the corner 3c (see Figure 3). Each lateral inclined surface 32 slopes towards the back surface 3B side as it extends outward in the width direction from the main surface 3A, and connects to the recess 20.

[0035] As shown in Figures 4, 5, and 7, the corner 3c of the main surface 3A is provided with a projection tip 23, a tip projection 22 including a first inclined surface 24, and a second inclined surface 25. The tip projection 22 and the second inclined surface 25 are provided between the cutting edge 5 and the ridge 30.

[0036] As shown in Figure 7, the tip projection 22 is provided on the inside of the corner blade 5a in the insert diameter direction. The tip projection 22 has a projection tip 23 on the rake face 21 side. The projection tip 23 rises from the rake face 21 toward the main surface 3A in the plate thickness direction, and the projection tip 23 has a spherically curved projection surface 23f that is convex toward the main surface 3A in the plate thickness direction. The projection surface 23f as a whole is inclined toward the main surface 3A toward the inside of the insert diameter direction. The projection surface 23f may be polyhedral as a whole, or a part of the projection surface 23f may be spherical and the other part polyhedral.

[0037] The first inclined surface 24 slopes inward from the tip of the projection 23 toward the back surface 3B in the radial direction of the insert. The first inclined surface 24 extends inward from the top 23t of the tip of the projection 23 toward the radial direction of the insert. As shown in Figure 6, the first inclined surface 24 is provided parallel to the back surface 3B in a cross-sectional view perpendicular to the bisector S of the corner 3c.

[0038] As shown in Figures 4, 5, and 7, the second inclined surface 25 is provided between the pair of lateral inclined surfaces 32. The second inclined surface 25 is inclined toward the main surface 3A toward the inside in the radial direction of the insert from the first inclined surface 24. The second inclined surface 25 is continuous with the top surface 31 of the ridge 30.

[0039] As shown in Figure 4, in this configuration, the angle θ1 formed by the cutting edge 5 located on one side of the angle bisector S of the corner 3c and the cutting edge 5 located on the other side of the angle bisector S, and the angle range θ2 in which the projection tip 23 and the rake face 21 span both sides of the angle bisector S of the corner 3c, are 0.35 ≤ θ² / θ¹ ≤ 0.85 It is preferable that this be the case.

[0040] As shown in Figure 7, in this embodiment, the top 23t of the projection tip 23 is lower than the cutting edge 5t of the corner blade 5a. Also, as shown in Figure 8, in this embodiment, when viewed from a direction perpendicular to the outer peripheral surface 4, the top 23t of the projection tip 23 protrudes in a direction intersecting the extension direction in which the straight blade 5b extends.

[0041] Furthermore, the first inclination angle θ3 (see Figure 7) in which the first inclined surface 24 is inclined with respect to a plane perpendicular to the plate thickness direction (a plane parallel to the main surface 3A) is relative to the second inclination angle θ4 (see Figure 8) in which the straight blade 5b is inclined with respect to a plane perpendicular to the plate thickness direction. θ3 > θ4 It is preferable that this be the case.

[0042] Furthermore, as shown in Figure 7, in the direction in which the angle bisector S of the corner portion 3c extends, the first distance L1 from the cutting edge 5t of the corner blade 5a to the intersection of the rake face 21 and the projection tip 23, and the second distance L2 from the cutting edge 5t of the corner blade 5a to the intersection of the first inclined surface 24 and the second inclined surface 25 are, 0.10 ≤ L1 / L2 ≤ 0.75 It is preferable to satisfy this relationship.

[0043] In this configuration, consider, for example, the case where the corner blade 5a is applied to the workpiece near point P on one side of the bisector S to perform cutting. In this case, the range in which the cutting edge 5 contacts the workpiece to cut it may change depending on the depth of cut. If the depth of cut is small, the cutting edge 5 cuts the workpiece in a narrow area including the corner blade 5a. In this case, the chips generated by cutting the workpiece hit the tip of the projection 23 from the corner blade 5a, and chip removal is performed. As the depth of cut increases, the range in which the cutting edge 5 contacts the workpiece expands from the corner blade 5a to the straight blade 5b side, and the chips generated by cutting the workpiece with the corner blade 5a and the straight blade 5b are processed along the first inclined surface 24. If the depth of cut increases further, the chips generated by cutting the workpiece with the corner blade 5a and the straight blade 5b hit the second inclined surface 25 and are removed.

[0044] [Effects of this embodiment] According to the cutting insert 1 of this embodiment described above, the main surface 3A has a projection tip 23, a first inclined surface 24, and a second inclined surface 25 at the corner 3c. As a result, the rake face 21, projection tip 23, first inclined surface 24, and second inclined surface 25 are sequentially formed at the corner 3c of the main surface 3A, moving inward from the corner blade 5a in the insert radial direction. The chips generated by cutting the workpiece with the corner blade 5a come into contact with at least one of the projection tip 23, the first inclined surface 24, and the second inclined surface 25, depending on the depth of cut. When the depth of cut is small and the feed rate is low, the chips come into contact with the projection tip 23, which is closer to the corner blade 5a. The chips curl upon contact with the projection tip 23, and the chips are processed well. Furthermore, as the depth of cut increases, the contact position of the chips moves from the projection tip 23 side to the first inclined surface 24 side. The first inclined surface 24 is inclined inward in the thickness direction toward the inside in the insert radial direction, so that the contact resistance when chips come into contact with the first inclined surface 24 is suppressed. This suppresses cutting resistance. When the depth of cut increases further, the contact position of the chips moves from the first inclined surface 24 side to the second inclined surface 25 side. The second inclined surface 25 is inclined outward in the thickness direction toward the inside in the insert radial direction. As the depth of cut increases, the chips become thicker and more robust. By bringing the thick chips into contact with the second inclined surface 25, the chips can be reliably guided away from the main surface 3A toward the outside in the thickness direction. In this way, it is possible to suppress cutting resistance while ensuring chip handling performance according to the depth of cut.

[0045] Furthermore, in this embodiment, the first inclined surface 24 is formed parallel to the back surface 3B in a cross-sectional view perpendicular to the bisector S of the corner portion 3c at the corner cutting edge 5a. By making the first inclined surface 24 a flat surface parallel to the back surface 3B, the area in contact with the chips at the same position in the thickness direction can be increased compared to when it is a curved surface protruding outward in the thickness direction. Therefore, the chip-receiving function can be improved.

[0046] In this embodiment, the first inclined surface 24 is inclined inward in the thickness direction from the top 23t of the projection tip 23 toward the inside in the diameter direction of the insert. As a result, the first inclined surface 24 is smoothly continuous from the top 23t of the projection tip 23, allowing for smooth guidance of chips.

[0047] Furthermore, in this embodiment, the angle θ1 formed by the cutting edge 5 located on one side of the bisector S of the corner 3c and the cutting edge 5 located on the other side of the bisector S is such that the angle range θ2 in which the projection tip 23 spans both sides of the bisector S is 0.35 ≤ θ2 / θ1 ≤ 0.85. As a result, the chips generated by cutting the workpiece with the corner cutting edge 5a are reliably guided from the rake face 21 to the projection tip 23. This ensures that the chips are brought into contact with the projection tip 23 and curled reliably.

[0048] Furthermore, if the angular range θ2 with respect to angle θ1 is less than 0.35, the distance between the cutting edge 5 and the projection tip 23 may be too great, potentially worsening chip handling performance. On the other hand, if the angular range θ2 with respect to angle θ1 exceeds 0.85, the distance between the cutting edge 5 and the projection tip 23 may be too great, potentially increasing cutting resistance excessively. According to this embodiment, by setting the angular range θ2 with respect to angle θ1 within the above-mentioned range, it is possible to improve chip handling performance while suppressing cutting resistance, thereby providing a cutting insert 1 with an excellent balance of these performances.

[0049] Furthermore, in this embodiment, the top 23t of the projection tip 23 is lower than the cutting edge 5t of the corner blade 5a. This ensures that, when the depth of cut is small, the chips generated by cutting the workpiece with the corner blade 5a can be reliably brought into contact with the projection tip 23 and curled.

[0050] Furthermore, in this embodiment, the top 23t of the projection tip 23 protrudes in a direction intersecting the extension direction of the straight blade 5b. This increases the depth of cut, and when cutting the workpiece with both the corner blade 5a and the straight blade 5b, the cutting resistance of the straight blade 5b can be suppressed by making the straight blade 5b lower than the top 23t of the projection tip 23.

[0051] Furthermore, in this embodiment, the first inclination angle θ3 of the first inclined surface 24 with respect to a plane perpendicular to the plate thickness direction is θ3 > θ4, where θ3 > θ4 is the second inclination angle θ4 of the straight blade 5b with respect to a plane perpendicular to the plate thickness direction. As a result, as the straight blade 5b moves away from the corner blade 5a, it becomes lower than the first inclined surface 24. Therefore, when cutting the workpiece with both the corner blade 5a and the straight blade 5b, lowering the straight blade 5b below the first inclined surface 24 can suppress the increase in cutting resistance at the straight blade 5b.

[0052] Furthermore, in this embodiment, in the direction in which the angle bisector S of the corner portion 3c extends, the first distance L1 from the cutting edge 5t of the corner blade 5a to the intersection of the rake face 21 and the projection tip 23, and the second distance L2 from the cutting edge 5t of the corner blade 5a to the intersection of the first inclined surface 24 and the second inclined surface 25 satisfy the relationship 0.10 ≤ L1 / L2 ≤ 0.75. This allows the position where chips contact the projection tip 23, the first inclined surface 24, and the second inclined surface 25 to be appropriately shifted according to the depth of cut. Moreover, by setting the first distance L1 and the second distance L2 to satisfy the above relationship, the chip handling efficiency can be improved within the range of conceivable depths of cut.

[0053] [Other components included in the present invention] Furthermore, the present invention is not limited to the embodiments described above, and the configurations (components) described in the embodiments, modifications, and provisos described above may be combined without departing from the spirit of the invention, and the configurations may be added, omitted, substituted, or otherwise modified. Moreover, the present invention is not limited by the embodiments described above, but is limited only by the claims. [Explanation of symbols]

[0054] 1…Cutting insert 2…Insert body 3A…Main surface 3B…Back surface<000C219>3c…Corner 4…Outer peripheral surface 5…Cutting edge 5a…Corner cutting edge 5b…Straight cutting edge<00OC224>5t…Tip 20a…Inclined surface 21…Relief surface 23…Tip of projection 23t…Top 24…First inclined surface 25…Second inclined surface L1…First distance L2…Second distance S…Bisector θ1…Angle θ2…Angle range θ3…First inclination angle θ4…Second inclination angle

Claims

1. A polygonal plate-shaped insert body, The insert body is provided with a main surface and a back surface which are polygonal in plan view and facing opposite directions in the thickness direction of the insert body, An outer peripheral surface connecting the peripheral edges of the main surface and the back surface, It comprises a cutting edge provided at the intersecting ridge line between the main surface and the outer peripheral surface, The aforementioned cutting edge is A corner blade located at the corner of the main surface, The intersecting ridge portion has a straight blade that extends inclined inward in the thickness direction as it moves away from the corner blade at the corner of the main surface, The corner portion of the aforementioned principal cell contains, A scoop surface provided on the inner side in the thickness direction relative to the main surface, The corner blade is provided on the inside in the insert radial direction perpendicular to the plate thickness direction, and the tip of the projection protrudes from the rake face in the plate thickness direction, A first inclined surface that slopes inward in the thickness direction from the tip of the projection toward the inside in the radial direction of the insert, It has a second inclined surface that is inclined outward in the thickness direction toward the inside in the radial direction of the insert, The tip of the projection has a spherically curved projection surface that faces outward in the radial direction of the insert, The first inclined surface is formed parallel to the back surface in a cross-sectional view perpendicular to the angle bisector of the corner portion of the corner blade. Cutting insert.

2. A polygonal plate-shaped insert body, The insert body is provided with a main surface and a back surface which are polygonal in plan view and facing opposite directions in the thickness direction of the insert body, An outer peripheral surface connecting the peripheral edges of the main surface and the back surface, It comprises a cutting edge provided at the intersecting ridge line between the main surface and the outer peripheral surface, The aforementioned cutting edge is A corner blade located at the corner of the main surface, The intersecting ridge portion has a straight blade that extends inclined inward in the thickness direction as it moves away from the corner blade at the corner of the main surface, The corner portion of the aforementioned principal cell contains, A scoop surface provided on the inner side in the thickness direction relative to the main surface, The corner blade is provided on the inside in the insert radial direction perpendicular to the plate thickness direction, and the tip of the projection protrudes from the rake face in the plate thickness direction, A first inclined surface that slopes inward in the thickness direction from the tip of the projection toward the inside in the radial direction of the insert, It has a second inclined surface that is inclined outward in the thickness direction toward the inside in the radial direction of the insert, The tip of the projection has a spherically curved projection surface that faces outward in the radial direction of the insert, The tip of the aforementioned projection is lower than the cutting edge of the corner blade. Cutting insert.

3. A polygonal plate-shaped insert body, The insert body is provided with a main surface and a back surface which are polygonal in plan view and facing opposite directions in the thickness direction of the insert body, An outer peripheral surface connecting the peripheral edges of the main surface and the back surface, It comprises a cutting edge provided at the intersecting ridge line between the main surface and the outer peripheral surface, The aforementioned cutting edge is A corner blade located at the corner of the main surface, The intersecting ridge portion has a straight blade that extends inclined inward in the thickness direction as it moves away from the corner blade at the corner of the main surface, The corner portion of the aforementioned principal cell contains, A scoop surface provided on the inner side in the thickness direction relative to the main surface, The corner blade is provided on the inside in the insert radial direction perpendicular to the plate thickness direction, and the tip of the projection protrudes from the rake face in the plate thickness direction, A first inclined surface that slopes inward in the thickness direction from the tip of the projection toward the inside in the radial direction of the insert, It has a second inclined surface that is inclined outward in the thickness direction toward the inside in the radial direction of the insert, The tip of the projection has a spherically curved projection surface that faces outward in the radial direction of the insert, The first inclination angle θ3, in which the first inclined surface is inclined with respect to a plane perpendicular to the plate thickness direction, is relative to the second inclination angle θ4, in which the straight blade is inclined with respect to a plane perpendicular to the plate thickness direction. θ3 > θ4 That is, Cutting insert.

4. The first inclined surface is inclined inward in the thickness direction from the top of the tip of the projection toward the inside in the diameter direction of the insert, A cutting insert according to any one of claims 1 to 3.

5. With respect to the angle θ1 between the cutting edge located on one side of the angle bisector and the cutting edge located on the other side of the angle bisector, The angular range θ2 in which the tip of the projection spans one side and the other side of the bisector is, 0.35 ≤ θ² / θ¹ ≤ 0.85 That is, A cutting insert according to any one of claims 1 to 4.

6. The tip of the projection protrudes in a direction intersecting the extension direction of the straight blade. A cutting insert according to any one of claims 1 to 5.

7. In the direction in which the angle bisector of the aforementioned corner extends, The first distance L1 is from the cutting edge of the corner blade to the intersection of the rake face and the tip of the projection, The second distance L2 from the cutting edge of the corner blade to the intersection of the first inclined surface and the second inclined surface is, 0.10 ≤ L1 / L2 ≤ 0.75 Satisfying A cutting insert according to any one of claims 1 to 6.

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