Cutting inserts and high feed milling tools

Abstract

The cutting insert for use in high-feed milling is rotationally symmetrical by 180° about a central axis (C) and comprises: first and second main surfaces (2, 3); a median plane (MP) extending between the main surfaces perpendicular to the central axis; a first main cutting edge (31) and an associated first ramping cutting edge (51); and a second main cutting edge and an associated second ramping cutting edge. Each main cutting edge has a first end (31a) facing the associated ramping cutting edge and an opposite second end (31b). Each ramping cutting edge has a first end (51a) facing the associated main cutting edge and an opposite second end (51b). The cutting edges are inclined such that their second ends are located closer to the median plane (MP) than their first ends, and the second ends of the main cutting edges are located closer to the median plane than the second ends of the ramping edges.

Description

[Technical Field]

[0001] The present invention relates to a cutting insert for high feed milling according to the preamble of claim 1. The present invention also relates to a high feed milling tool comprising such a cutting insert. [Background technology]

[0002] A milling tool is a rotary cutting tool that may include one or more cutting inserts. A milling tool may take the form of an end mill that can be used in high feed milling, for example, to perform ramping operations, including pocketing.

[0003] Indexable cutting inserts for high feed milling have been known for some time in various configurations, and examples of such cutting inserts are disclosed, for example, in U.S. Pat. No. 10,245,695 (B2) and European Patent Application Publication No. 3,199,284 (A1). Summary of the Invention

[0004] Object of the invention SUMMARY OF THE INVENTION It is an object of the present invention to provide a cutting insert of the above type with a new and preferred design.

[0005] According to the present invention, this object is achieved by a cutting insert having the features defined in claim 1.

[0006] The cutting insert according to the present invention comprises: - first and second major surfaces disposed on opposite sides of the cutting insert and serving as a top and bottom surface of the cutting insert, the first and second major surfaces being rotationally symmetrical by 180° about a central axis of the cutting insert extending between the first and second major surfaces; a peripheral flank surface extending around the cutting insert between the first and second major surfaces and comprising a first major side surface, a second major side surface, a third major side surface, a fourth major side surface, a first corner side surface, a second corner side surface, a third corner side surface, and a fourth corner side surface; the first corner side is disposed between the first major side and the second major side; a second corner side disposed between the second major side and the third major side; a third corner side disposed between the third major side and the fourth major side; a fourth corner side disposed between the first major side and the fourth major side; the first major side and the third major side form a first opposing major side pair; The first two major sides and the fourth major side form a second pair of opposing major sides. The surrounding relief surface and a first side cutting edge formed at an intersection of the first main side surface and the first main surface; a second side cutting edge formed at an intersection of the third major side surface and the first major surface; a first major cutting edge, a first minor cutting edge, and a first ramping cutting edge formed at an intersection of the second major side surface and the first major surface, the first minor cutting edge being disposed between the first major cutting edge and the first ramping cutting edge; a second main cutting edge, a second minor cutting edge, and a second ramping cutting edge formed at an intersection of the fourth major side surface and the first major surface, the second minor cutting edge being disposed between the second main cutting edge and the second ramping cutting edge, and the shortest distance between the opposing first main cutting edge and the second main cutting edge being equal to or longer than the shortest distance between the opposing first side cutting edge and the second side cutting edge; a first curved corner cutting edge formed at an intersection of the first corner side surface and the first main surface, the first curved corner cutting edge being disposed between the first side cutting edge and the first main cutting edge; a second curved corner cutting edge formed at an intersection of the second corner side surface and the first main surface, the second curved corner cutting edge being disposed between the first ramping cutting edge and the second side cutting edge; a third curved corner cutting edge formed at an intersection of the third corner side surface and the first main surface, the third curved corner cutting edge being disposed between the second side cutting edge and the second main cutting edge; a fourth curved corner cutting edge formed at an intersection of the fourth corner side surface and the first main surface, the fourth curved corner cutting edge being disposed between the second ramping cutting edge and the first side cutting edge; Equipped with.

[0007] When viewed in a plan view of the cutting insert, the first main cutting edge and the first ramping cutting edge extend at an obtuse angle relative to each other, and when viewed in a plan view of the cutting insert, the second main cutting edge and the second ramping cutting edge extend at a corresponding obtuse angle relative to each other. A plan view is a view from above, i.e., a top view, and corresponds here to a view of the cutting insert from directly above the first main surface in the direction of the central axis of the cutting insert. In other words, a plan view is a view looking toward the first main surface along the central axis. Thus, the plan view of the cutting insert constitutes an observation plane perpendicular to the central axis of the cutting insert. If the first and second main cutting edges and / or the first and second ramping cutting edges are curved when viewed in a plan view of the cutting insert, the extension direction of any of these curved cutting edges in the plan view is defined by a straight line intersecting the two opposite end points of the cutting edge. The obtuse angle is usually in the range of 95° to 160°, preferably in the range of 100° to 125°, and more preferably in the range of 112°±5°.

[0008] An imaginary median plane extends perpendicular to the central axis of the cutting insert midway between the first and second major surfaces of the cutting insert, and is introduced herein to allow the invention to be properly defined.

[0009] The first major cutting edge has a first end connected to the first minor cutting edge and a second end connected to the first curved corner cutting edge, the second major cutting edge has a first end connected to the second minor cutting edge and a second end connected to the third curved corner cutting edge, and each of the first and second major cutting edges has one or more slopes between its first and second ends such that its second end is located closer to the median plane than its first end. Thus, when viewed relative to the median plane, the second end of each major cutting edge facing the adjacent curved corner cutting edge is located at a lower height, i.e., closer to the median plane, than the first end of each major cutting edge facing the adjacent minor cutting edge.

[0010] The first ramping edge has a first end connected to the first minor cutting edge and a second end connected to the second curved corner cutting edge, the second ramping edge has a first end connected to the second minor cutting edge and a second end connected to the fourth curved corner cutting edge, and each of the first and second ramping edges has one or more slopes between its first and second ends such that its second end is located closer to the median plane than its first end. Thus, when viewed relative to the median plane, the second end of each ramping edge facing the adjacent curved corner cutting edge is located at a lower height, i.e., closer to the median plane, than the first end of each ramping edge facing the adjacent minor cutting edge.

[0011] According to the present invention, the second ends of the first and second main cutting edges are positioned closer to the median plane than the second ends of the first and second ramping cutting edges. Thus, when viewed relative to the median plane, the second end of the first main cutting edge is positioned lower in height than the second end of the first ramping edge, and the second end of the second main cutting edge is positioned lower in height than the second end of the second ramping edge. This feature improves the performance of the cutting insert in ramping operations, including pocket milling, by providing smoother cutting and reducing the risk of chips being trapped between the workpiece and the surrounding flank portions associated with the effective main cutting edge and the effective corner cutting edge. By effective corner cutting edge, we mean a corner cutting edge adjacent to and between the effective main cutting edge and the side cutting edge. Furthermore, in pocket milling, this feature reduces the risk of chips being trapped in the bottom and vertical walls of the pocket being machined in the workpiece.

[0012] When the cutting insert is mounted in the insert seat of the tool body of the milling tool, one of the main cutting edges is arranged to form an effective main cutting edge of the milling tool, the associated ramping cutting edge is arranged to form an effective ramping cutting edge of the milling tool, and the curved corner cutting edge adjacent to the effective main cutting edge is arranged to form an effective corner cutting edge of the milling tool. The effective main cutting edge is arranged with its first end facing radially inward of the tool body toward the rotation axis of the milling tool and its second end facing radially outward of the tool body away from the rotation axis of the milling tool, while the effective ramping cutting edge is arranged radially inward of the effective main cutting edge. By positioning the second end of the effective main cutting edge closer to the median plane than the second end of the effective ramping cutting edge, chips formed by the second end of the effective ramping edge have an improved tendency to move from the effective ramping edge toward the effective main cutting edge and the effective corner cutting edge, i.e., radially outward from the tool body, instead of moving radially inward from the effective ramping edge. If the chips move radially inward from the effective ramping edge, they may reach the area below the effective main cutting edge and become trapped between the workpiece and portions of the surrounding flank surface associated with the effective main cutting edge and the effective corner cutting edge.

[0013] According to an embodiment of the present invention, each of the first and second major cutting edges is inclined toward the median plane along a major portion of its length from its first end to its second end, preferably along its entire length from its first end to its second end. This allows chips formed by the active ramping edge to move smoothly along the active main cutting edge. Each of the first and second ramping edges is also preferably inclined toward the median plane along its entire length from its first end to its second end.

[0014] According to another embodiment of the invention, each of the first and second major cutting edges, when viewed along its entire length from its first end to its second end, is inclined toward the median plane at a constant or increasing incline, such that no portion of the active major cutting edge can impede the movement of the chip along the major cutting edge.

[0015] According to another embodiment of the present invention, when viewed in a viewing direction parallel to the median plane and perpendicular to a first line of intersection between the first and second ends of the first main cutting edge, the first main cutting edge extends along a straight or convex line, or along a line that is a series of one or more straight lines combined with one or more convex lines, and when viewed in a viewing direction parallel to the median plane and perpendicular to a second line of intersection between the first and second ends of the second main cutting edge, the second main cutting edge extends along a corresponding line, which facilitates manufacturing of the cutting insert and improves the above-mentioned chip movement along the active main cutting edge.

[0016] Each of the first and third curved corner cutting edges has a first end connected to the adjacent main cutting edge and a second end connected to the adjacent side cutting edge. Preferably, each of the first and third curved corner cutting edges has one or more slopes between its first and second ends, such that its second end is positioned closer to the median plane than its first end. Therefore, when viewed relative to the median plane, the second ends of each of the first and third curved corner cutting edges are positioned lower in height than their first ends, which in turn are positioned lower in height than the second ends of the adjacent main cutting edges. This allows chips formed by the effective ramping cutting edge to easily continue moving radially outward along the sloped effective corner cutting edge after moving radially outward along the sloped effective main cutting edge. Chips formed by the effective main cutting edge can also easily move radially outward along the sloped effective corner cutting edge.

[0017] According to another embodiment of the invention, each of the first and third curved corner edges is inclined toward the median plane along its entire length from its first end to its second end, thereby allowing chips formed by the active ramping edge to move smoothly along the active corner edge.

[0018] According to another embodiment of the invention, each of the first and third curved corner edges, when viewed along its entire length from its first end to its second end, is inclined toward the median plane at a constant or increasing slope, such that no portion of the corner edge is active that could impede the movement of the chip along the corner edge.

[0019] According to another embodiment of the invention, the first and third curved corner cutting edges are configured such that at any point along either the first or third curved corner cutting edge, the curved corner edge has a slope that is equal to or greater than the minimum slope of the adjacent major cutting edge at any point along that major cutting edge, thereby effectively preventing the active corner cutting edge from impeding the movement of said chip radially outward along the active corner cutting edge.

[0020] According to another embodiment of the invention, the first and third curved corner cutting edges are configured such that, at any point along either the first or third curved corner cutting edge, the distance between the curved corner edge and the median plane is equal to or less than the distance between the second end of the adjacent major cutting edge and the median plane, thereby facilitating radial outward movement of the chip along the active corner edge.

[0021] According to another embodiment of the present invention, the first main cutting edge and the first curved corner cutting edge are configured such that, when viewed in a viewing direction parallel to the median plane and perpendicular to a first straight line of intersection between the first and second ends of the first main cutting edge, the first curved corner cutting edge is located between the median plane and any tangent line that can be drawn to a point along the first main cutting edge, and the second main cutting edge and the third curved corner cutting edge are configured such that, when viewed in a viewing direction parallel to the median plane and perpendicular to a second straight line of intersection between the first and second ends of the second main cutting edge, the third curved corner cutting edge is located between the median plane and any tangent line that can be drawn to a point along the second main cutting edge, thereby efficiently preventing the effective corner cutting edge from impeding the movement of the chip radially outward along the effective corner cutting edge. If the first main cutting edge comprises a region that extends in a straight line when viewed in a viewing direction parallel to the median plane and perpendicular to the first line of intersection, an imaginary line that is aligned with this region and forms its extension is considered here to correspond to a tangent to any point along this region. If the second main cutting edge comprises a region that extends in a straight line when viewed in a viewing direction parallel to the median plane and perpendicular to the second line of intersection, an imaginary line that is aligned with this region and forms its extension is considered here to correspond to a tangent to any point along this region.

[0022] Another embodiment of the present invention is a first chip breaker associated with the first main cutting edge is formed in the first major surface and extends along at least a portion of the first main cutting edge, preferably along the entire length of the first main cutting edge, the first chip breaker having a first end facing towards the first ramping cutting edge and an opposite second end facing towards the first major side, the first chip breaker also preferably being associated with the first curved corner cutting edge and configured to extend along the first curved corner cutting edge; a second chip breaker associated with the second main cutting edge is formed in the first major side and extends along at least a portion of the second main cutting edge, preferably along the entire length of the second main cutting edge, the second chip breaker having a first end facing the second ramping cutting edge and an opposite second end facing the third major side, the second chip breaker also preferably being associated with the third curved corner cutting edge and configured to extend along the third curved corner cutting edge; It is characterized by:

[0023] These chip breakers contribute to more favorable formation or breaking of chips formed by the active major cutting edge and to moving these chips in a favorable direction, thereby improving the cutting process. These chip breakers also facilitate the radial outward movement of chips formed by the active ramping edge, thereby improving the evacuation of these chips. A first end of the first chip breaker may be somewhat contiguous adjacent to another chip breaker associated with the first minor cutting edge and, in some cases, associated with the first ramping edge, and a first end of the second chip breaker may be somewhat contiguous adjacent to another chip breaker associated with the second minor cutting edge and, in some cases, associated with the second ramping edge.

[0024] The second end of the first chip breaker is preferably adjacent to the second end of the first curved corner cutting edge, i.e., adjacent to the end connecting to the first side cutting edge, and the second end of the second chip breaker is preferably adjacent to the second end of the third curved corner cutting edge, i.e., adjacent to the end connecting to the second side cutting edge. The second end of the first chip breaker is also preferably adjacent to a portion of the first side cutting edge, and the second end of the second chip breaker is also preferably adjacent to a portion of the second side cutting edge.

[0025] Another embodiment of the present invention is - the first chip breaker extends perpendicular to the median plane midway between the first major side and the third major side and has a substantially U-shaped or V-shaped profile when a cross section of the first chip breaker is viewed parallel to a longitudinal plane of the cutting insert containing the central axis, thereby forming an elongated first valley in the first major side extending between a first end and a second end of the first chip breaker; the second chip breaker has a substantially U-shaped or V-shaped profile when a cross section of the second chip breaker is viewed parallel to said longitudinal plane, thereby forming an elongated second valley in the first major surface extending between the first end and the second end of the second chip breaker; The present invention is characterized in that an elongated valley is provided in the first major surface along the effective main cutting edge from a region adjacent to the effective ramping edge in a direction toward the effective main side cutting edge, and the valley functions as a conventional chip breaker for chips formed by the effective main cutting edge and also facilitates the outward movement of chips formed by the effective ramping edge.

[0026] According to another embodiment of the invention, the first valley has an increasing depth when viewed in a direction along the first chip breaker from the first end of the first chip breaker toward the second end of the first chip breaker, and the second valley has an increasing depth when viewed in a direction along the second chip breaker from the first end of the second chip breaker toward the second end of the second chip breaker. This design of the valleys formed by the first and second chip breakers further promotes outward movement of chips formed by the effective ramping cutting edge.

[0027] According to another embodiment of the present invention, the first valley has an increasing width when viewed along the first chip breaker from the first end of the first chip breaker to the second end of the first chip breaker, and the second valley has an increasing width when viewed along the second chip breaker from the first end of the second chip breaker to the second end of the second chip breaker. This design of the valleys formed by the first and second chip breakers further promotes outward movement of chips formed by the effective ramping cutting edge. Here, the width of the valley refers to the distance between two opposing longitudinal edges of the valley as measured in a plane extending parallel to the longitudinal surface of the cutting insert.

[0028] According to another embodiment of the invention, each of the first and second major cutting edges, and preferably also each of the first and second minor cutting edges, has a nominal rake angle that is positive or zero, which further promotes the outward movement of chips formed by the effective ramping edges.

[0029] The cutting insert of the present invention is advantageously a single-sided, two-way indexable cutting insert, with the second major surface preferably being flat and extending perpendicular to the central axis, which facilitates manufacturing of the cutting insert. However, the cutting insert of the present invention may alternatively be a double-sided, four-way indexable cutting insert, with cutting edges similarly arranged around both of the major surfaces of the cutting insert.

[0030] Further advantageous features of the cutting insert according to the invention will become apparent from the following description.

[0031] The invention also relates to a high-feed milling tool equipped with a cutting insert of the type described above.

[0032] Further advantageous features of the high feed milling tool according to the invention will become apparent from the following description.

[0033] Embodiments of the invention will now be described in greater detail, by way of example, with reference to the accompanying drawings, in which: [Brief explanation of the drawings]

[0034] [Figures 1a-1c] 1A to 1C are perspective views of a cutting insert according to a first embodiment of the present invention, viewed from different directions. [Figure 1d] FIG. 2 is a plan view of the cutting insert of FIGS. 1a to 1c as viewed from above. [Figures 1e-1j] 1A to 1C are lateral views of the cutting insert of FIG. 1A to FIG. 1C, as viewed from different sides. [Figures 2a-2c] FIG. 6 is a perspective view of a cutting insert according to a second embodiment of the present invention, viewed from a different direction. [Figure 2d] FIG. 2B is a plan view of the cutting insert of FIGS. 2a to 2c as viewed from above. [Figures 2e-2j] 2a to 2c are lateral views of the cutting insert as viewed from different sides. [Figure 3] 1a to 1j show a lateral view of a milling tool with a cutting insert according to the embodiment shown in FIGS. 1a to 1j. [Figure 4] FIG. 4 is a front view of the milling tool of FIG. 3. [Figure 5] FIG. 4 is a perspective view of the front end of the milling tool of FIG. 3; [Figure 6] 6 is a perspective view corresponding to FIG. 5, showing the cutting insert removed from the insert seat of the tool body of the milling tool. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0035] Two different embodiments of a cutting insert 1 according to the present invention are shown in Figures 1a to 1j and 2a to 2j. The cutting insert 1 is configured for use in high feed milling and for use with a milling tool 80, for example a milling tool of the type shown in Figures 3 to 6. The cutting insert 1 is particularly configured for use in ramping operations, including pocketing.

[0036] The cutting insert 1 has first and second main surfaces 2, 3 disposed on opposite sides of the cutting insert 1 and functioning as the top and bottom surfaces of the cutting insert. The cutting insert 1 has a central axis C extending between the first main surface 2 and the second main surface 3, and the cutting insert 1 is rotationally symmetric by 180° about the central axis C. A median plane MP constituting an imaginary plane extends perpendicular to the central axis C midway between the first main surface 2 and the second main surface 3.

[0037] In the illustrated embodiment, the cutting insert 1 comprises a through hole 5 extending through the center of the cutting insert between the first major surface 2 and the second major surface 3. The through hole 5 is configured to receive a fastening element 6, for example in the form of a screw (see FIGS. 3, 5, and 6), by which the cutting insert 1 can be removably secured to an insert seat 84 of a milling tool 80. The central axis C of the cutting insert 1 coincides with the central axis of the through hole 5. The cutting insert 1 may alternatively be without the through hole 5, in which case the cutting insert is configured to be removably secured to an insert seat of a milling tool by suitable clamping means.

[0038] A peripheral flank surface 10 extends around the cutting insert 1 between the first major surface 2 and the second major surface 3. The peripheral flank surface 10 comprises a first major side surface 11, a second major side surface 12, a third major side surface 13, and a fourth major side surface 14. The peripheral flank surface 10 also comprises a first corner side 15 disposed between the first major side 11 and the second major side 12; a second corner side 16 disposed between the second major side 12 and the third major side 13; a third corner side 17 disposed between the third major side 13 and the fourth major side 14; a fourth corner side 18 disposed between the first major side 11 and the fourth major side 14; Equipped with.

[0039] The first major side surface 11 and the third major side surface 13 form a first pair of opposing major side surfaces, and the second major side surface 12 and the fourth major side surface 14 form a second pair of opposing major side surfaces. A longitudinal plane LP (see FIGS. 1d and 2d ) constituting an imaginary plane extends across the cutting insert 1 perpendicular to the median plane MP midway between the first major side surface 11 and the third major side surface 13 and includes a central axis C. Thus, the central axis C has its extension within this longitudinal plane LP. A central plane CP constituting another imaginary plane extends across the cutting insert 1 perpendicular to the median plane MP and perpendicular to the longitudinal plane LP and includes the central axis C. Thus, the central axis C also has its extension within this central plane CP, such that the central axis C extends along the intersection of the longitudinal plane LP and the central plane C. A longitudinal plane LP extends between the second major side surface 12 and the fourth major side surface 14 , and a central plane CP extends between the first major side surface 11 and the third major side surface 13 .

[0040] The first side cutting edge 21 extends along the first major side surface 11 and is formed at the intersection of the first major side surface 11 and the first major surface 2. The second side cutting edge 22 extends along the third major side surface 13 and is formed at the intersection of the third major side surface 13 and the first major surface 2.

[0041] The first major cutting edge 31, the first minor cutting edge 41, and the first ramping cutting edge 51 extend in sequence along the second major side surface 12 and are formed at the intersection of the second major side surface 12 and the first major surface 2. The first minor cutting edge 41 is disposed between the first major cutting edge 31 and the first ramping cutting edge 51.

[0042] The second major cutting edge 32, the second minor cutting edge 42, and the second ramping cutting edge 52 extend in sequence along the fourth major side surface 14 and are formed at the intersection of the fourth major side surface 14 and the first major surface 2. The second minor cutting edge 42 is disposed between the second major cutting edge 32 and the second ramping cutting edge 52.

[0043] Each of the first and second minor cutting edges 41, 42 includes a surface scraping cutting edge section 43.

[0044] The first side cutting edge 21 and the second side cutting edge 22 are arranged opposite each other on opposite sides of the longitudinal plane LP, as shown in FIGS. 1d and 2d. The first major cutting edge 31 and the second major cutting edge 32 are arranged opposite each other on opposite sides of the central plane CP. In the embodiment shown in FIGS. 2a to 2j, the first major cutting edge 31 and the second major cutting edge 32 are also arranged opposite each other on opposite sides of the longitudinal plane LP. The first minor cutting edge 41 and the second minor cutting edge 42 are arranged opposite each other on opposite sides of the central plane CP. In the embodiment shown in FIGS. 1a to 1j, the first minor cutting edge 41 and the second minor cutting edge 42 are also arranged opposite each other on opposite sides of the longitudinal plane LP. The first ramping cutting edge 51 and the second ramping cutting edge 52 are arranged opposite each other on opposite sides of the central plane CP and also opposite the longitudinal plane LP.

[0045] The cutting insert 1 of the present invention has a shape such that the shortest distance d1 between the opposing first major cutting edge 31 and second major cutting edge 32 is equal to or longer than the shortest distance d2 between the opposing first side cutting edge 21 and second side cutting edge 22. The relationship between the distance d1 and the distance d2 is such that d1 / d2 is preferably greater than 1.1, more preferably 1.1 to 2.0, even more preferably 1.2 to 1.7, and most preferably 1.36 to 1.46.

[0046] As shown in Figures 1d and 2d, the cutting insert 1 of the present invention also has a shape such that, when viewed in a plan view of the cutting insert 1, i.e., when viewed from above, the first main cutting edge 31 and the first ramping cutting edge 51 extend at an obtuse angle α relative to each other, and when viewed in a plan view of the cutting insert, the second main cutting edge 32 and the second ramping cutting edge 52 extend at a corresponding obtuse angle α relative to each other. In the embodiment shown in Figures 1a to 1j, the first and second main cutting edges 31, 32 are slightly convex when viewed in a plan view. In this case, the angle α between the first ramping cutting edge 51 and the first main cutting edge 31 is measured between a line extending along the first ramping cutting edge 51 in the plan view and a line intersecting the two opposite end points 31a, 31b of the first main cutting edge 31, and the angle α between the second ramping cutting edge 52 and the second main cutting edge 32 is measured in a corresponding manner. The angle α is approximately 112° in the embodiment shown in Figures 1a to 1j and approximately 150° in the embodiment shown in Figures 2a to 2j, but may be any other suitable value, preferably in the range of 95° to 160°, and more preferably in the range of 100° to 125°.

[0047] The first curved corner cutting edge 61 extends along the first corner side 15 and is formed at the intersection of the first corner side 15 and the first major surface 2. The second curved corner cutting edge 62 extends along the second corner side 16 and is formed at the intersection of the second corner side 16 and the first major surface 2. The third curved corner cutting edge 63 extends along the third corner side 17 and is formed at the intersection of the third corner side 17 and the first major surface 2. The fourth curved corner cutting edge 64 extends along the fourth corner side 18 and is formed at the intersection of the fourth corner side 18 and the first major surface 2. The first curved corner cutting edge 61 extends between the first side cutting edge 21 and the first main cutting edge 31, the second curved corner cutting edge 62 extends between the first ramping cutting edge 51 and the second side cutting edge 22, the third curved corner cutting edge 63 extends between the second side cutting edge 22 and the second main cutting edge 32, and the fourth curved corner cutting edge 64 extends between the second ramping cutting edge 52 and the first side cutting edge 21. The first, second, third, and fourth curved corner cutting edges 61, 62, 63, 64 extend along respective radiused corners of the cutting insert. The first curved corner cutting edge 61 and the third curved corner cutting edge 63 are diagonally opposed to each other on opposite sides of the longitudinal plane LP and on opposite sides of the central plane CP. The second curved corner cutting edge 62 and the fourth curved corner cutting edge 64 are disposed diagonally opposite each other on opposite sides of the longitudinal plane LP and on opposite sides of the central plane CP.

[0048] The above definition of 180° rotational symmetry around the central axis C means: - the first side cutting edge 21 and the second side cutting edge 22 are identical to each other within manufacturing tolerances - the first main cutting edge 31 and the second main cutting edge 32 are identical to each other within manufacturing tolerances The first minor cutting edge 41 and the second minor cutting edge 42 are identical to each other within manufacturing tolerances. - the first ramping cutting edge 51 and the second ramping cutting edge 52 are identical to each other within manufacturing tolerances - the first curved corner cutting edge 61 and the third curved corner cutting edge 63 are identical to each other within manufacturing tolerances The second curved corner cutting edge 62 and the fourth curved corner cutting edge 64 are identical to one another within manufacturing tolerances. This means that...

[0049] The first major cutting edge 31 has a first end 31a connected to the first minor cutting edge 41 and a second end 31b connected to the first curved corner cutting edge 61. The second major cutting edge 32 has a first end 32a connected to the second minor cutting edge 42 and a second end 32b connected to the third curved corner cutting edge 63. The first major cutting edge 31 has one or more sloped sections between its first end 31a and second end 31b, with one or more slopes such that the second end 31b is positioned closer to the median plane MP than the first end 31a. The second major cutting edge 32 is inclined in the same manner as the first major cutting edge 31 and has one or more sloped sections between its first end 32a and second end 32b, with one or more slopes such that the second end 32b is positioned closer to the median plane MP than the first end 32a.

[0050] The first ramping cutting edge 51 has a first end 51a connected to the first minor cutting edge 41 and a second end 51b connected to the second curved corner cutting edge 62. The second ramping cutting edge 52 has a first end 52a connected to the second minor cutting edge 42 and a second end 52b connected to the fourth curved corner cutting edge 64. The first ramping cutting edge 51 has one or more sloped sections between its first end 51a and second end 51b, with one or more slopes such that the second end 51b is positioned closer to the median plane MP than the first end 51a. The second ramping cutting edge 52 is sloped in the same manner as the first ramping cutting edge 51 and has one or more sloped sections between its first end 52a and second end 52b, with one or more slopes such that the second end 52b is positioned closer to the median plane MP than the first end 52a.

[0051] According to the present invention, as shown in Figures 1g and 2g, the second end 31b of the first main cutting edge 31 is positioned closer to the median plane MP than the second end 51b of the first ramping cutting edge 51, and correspondingly, the second end 32b of the second main cutting edge 32 is positioned closer to the median plane MP than the second end 52b of the second ramping cutting edge 52, as shown in Figures 1h and 2h. Thus, the second ends 31b, 32b of the main cutting edges 31, 32 are positioned between the median plane MP and an imaginary reference plane RP that intersects with the second ends 51b, 52b of the ramping cutting edges 51, 52 and extends parallel to the median plane MP, as shown in Figures 1g, 1h, 2g, and 2h. Figures 1g and 2g show the cutting insert 1 in a viewing direction parallel to the median plane MP and perpendicular to the line of intersection L3 where the second end 31b of the first main cutting edge 31 and the second end 51b of the first ramping cutting edge 51 intersect, and Figures 1h and 2h show the cutting insert 1 in a viewing direction parallel to the median plane MP and perpendicular to the line of intersection L4 where the second end 32b of the second main cutting edge 32 and the second end 52b of the second ramping cutting edge 52 intersect.

[0052] In the illustrated embodiment, each of the ramping edges 51, 52 is inclined toward the median plane MP along its entire length from its first end 51 a, 52 a to its second end 51 b, 52 b. Each of the major cutting edges 31, 32 is inclined toward the median plane MP along a major portion of its length from its first end 31 a, 32 a to its second end 31 b, 32 b. The major cutting edges 31, 32 and / or the ramping edges 51, 52 may alternatively include one or more sections extending parallel to the median plane MP. The major cutting edges 31, 32 may have a convex section adjacent their first ends 31 a, 32 a. As a further alternative, the convex area may have a portion that slopes away from the median plane MP when viewed along the main cutting edge from its first end toward its second end, in order to provide a smoother transition between the ramping edge 51, 52 and the main cutting edge 31, 32. Preferably, each of the main cutting edges 31, 32 and ramping edges 51, 52 slopes toward the median plane MP at a constant or increasing slope when viewed along its entire length from its first end 31 a, 32 a, 51 a, 52 a to its second end 31 b, 32 b, 51 b, 52 b.

[0053] In the embodiment shown in Figures 1a to 1j, as shown in Figure 1i, the first major cutting edge 31 extends to its main portion along a straight line or substantially a straight line when viewed in a viewing direction parallel to the median plane MP and perpendicular to the line of intersection L1 where the first and second ends 31a, 31b of the first major cutting edge are intersected, and has a convex portion adjacent to its first end 31a. In this case, as shown in Figure 1j, the second major cutting edge 32 extends to its main portion along a corresponding straight line or substantially a straight line when viewed in a viewing direction parallel to the median plane MP and perpendicular to the line of intersection L2 where the first and second ends 32a, 32b of the second major cutting edge 32 are intersected. Furthermore, in the embodiment shown in Figures 2a to 2j, as shown in Figures 2i and 2j, when viewed in the aforementioned viewing direction, the first and second main cutting edges 31, 32 extend along a straight line or at least substantially a straight line.

[0054] The first curved corner cutting edge 61 has a first end 61a connected to the second end 31b of the first main cutting edge 31 and a second end 61b connected to the first side cutting edge 21. The third curved corner cutting edge 63 has a first end 63a connected to the second end 32b of the second main cutting edge 32 and a second end 63b connected to the second side cutting edge 22. The first and third curved corner cutting edges 61, 63 may extend parallel to the median plane MP. However, in the illustrated embodiment, the first curved corner cutting edge 61 has one or more inclined portions between its first end 61a and second end 61b, with one or more inclinations such that its second end 61b is positioned closer to the median plane MP than its first end 61a, and in this case the third curved corner cutting edge 63 has one or more inclined portions between its first end 63a and second end 63b, with one or more inclinations such that its second end 63b is positioned closer to the median plane MP than its first end 63a.

[0055] In the illustrated embodiment, each of the first and third curved corner cutting edges 61, 63 is inclined toward the median plane MP along its entire length from its first end 61 a, 63 a to its second end 61 b, 63 b, but may alternatively include one or more sections extending parallel to the median plane MP. Preferably, each of the first and third curved corner cutting edges 61, 63 is inclined toward the median plane MP at a constant or increasing slope when viewed along its entire length from its first end 61 a, 63 a to its second end 61 b, 63 b.

[0056] It is preferred that the first curved corner cutting edge 61 has, at every point along its extension, a slope equal to or greater than the minimum slope of the first main cutting edge 31 at every point along the first main cutting edge 31, in which case the third curved corner cutting edge 63 has, at every point along its extension, a slope equal to or greater than the minimum slope of the second main cutting edge 32 at every point along the second main cutting edge 32.

[0057] At every point along the first curved corner cutting edge 61, it is preferable that the distance between the first curved corner cutting edge 61 and the median plane MP is equal to or less than the distance between the second end 31b of the first main cutting edge 31 and the median plane MP, and in this case, at every point along the third curved corner cutting edge 63, the distance between the third curved corner cutting edge 63 and the median plane MP is equal to or less than the distance between the second end 32b of the second main cutting edge 32 and the median plane MP.

[0058] Furthermore, the first main cutting edge 31 and the first curved corner cutting edge 61 are preferably configured such that when viewed in a viewing direction parallel to the median plane MP and perpendicular to the line of intersection L1 between the first and second ends 31a, 31b of the first main cutting edge 31, i.e., when viewed in the lateral views of Figures 1i and 2i, the first curved corner cutting edge 61 is located between the median plane MP and any tangent that can be drawn to a point along the first main cutting edge 31. In this case, the second main cutting edge 32 and the third curved corner cutting edge 63 are configured so that when viewed from a viewing direction parallel to the median plane MP and perpendicular to the line of intersection L2 that intersects the first and second ends 32a, 32b of the second main cutting edge 32, i.e., when viewing the lateral views of Figures 1j and 2j, the third curved corner cutting edge 63 is located between the median plane MP and any tangent that can be drawn to a point along the second main cutting edge 32.

[0059] Advantageously, the first chip breaker 71 associated with the first main cutting edge 31 is formed on the first main surface 2 and configured to extend along at least a portion of the first main cutting edge 31 to the first main surface 2, and in this case the second chip breaker 72 associated with the second main cutting edge 32 is formed on the first main surface 2 and configured to extend along at least a portion of the second main cutting edge 32 to the first main surface 2. Preferably, the first and second chip breakers 71, 72 are configured to extend all the way along the first and second main cutting edges 31, 32. In the illustrated embodiment, the first chip breaker 71 extends all the way along the first main cutting edge 31 and also extends along the first curved corner edge 61, and in this case the second chip breaker 72 extends all the way along the second main cutting edge 32 and also extends along the third curved corner edge 63. The first chip breaker 71 and the second chip breaker 72 are therefore also associated in this case with the first curved corner cutting edge 61 and the third curved corner cutting edge 63, respectively. The first chip breaker 71 has a first end 71 a facing towards the first ramping cutting edge 51 and an opposite second end 71 b facing towards the first major side surface 11, and in this case the second chip breaker 72 has a first end 72 a facing towards the second ramping cutting edge 52 and an opposite second end 72 b facing towards the third major side surface 13. In the illustrated embodiment, the second end 71b of the first chip breaker 71 is adjacent to the second end 61b of the first curved corner cutting edge 61 and also adjacent to a portion of the first side cutting edge 21 adjacent to the second end 61b of the first curved corner cutting edge 61, while the second end 72b of the second chip breaker 72 is adjacent to the second end 63b of the third curved corner cutting edge 63 and also adjacent to a portion of the second side cutting edge 22 adjacent to the second end 63b of the third curved corner cutting edge 63.

[0060] 1a-1j, the first end 71a of the first chip breaker 71 is adjacent to the third chip breaker 76 associated with the first minor cutting edge 41 and the first ramping cutting edge 51, while the first end 72a of the second chip breaker 72 is adjacent to the fourth chip breaker 77 associated with the second minor cutting edge 42 and the second ramping cutting edge 52. The first chip breaker 71 and the third chip breaker 76 together form a continuous chip breaker that extends all the way between the first ramping cutting edge 51 and a portion of the first side cutting edge 21. The second chip breaker 72 and the fourth chip breaker 77 together form a continuous chip breaker that extends all the way between the second ramping cutting edge 52 and a portion of the second side cutting edge 22.

[0061] Preferably, the first chip breaker 71 has a substantially U- or V-shaped profile when viewed in cross section parallel to the longitudinal plane LP, thereby forming an elongated first valley 73 in the first main surface 2, extending between the first end 71 a and the second end 71 b of the first chip breaker. Similarly, the second chip breaker 72 has a substantially U- or V-shaped profile when viewed in cross section parallel to the longitudinal plane LP, thereby forming an elongated second valley 74 in the first main surface 2, extending between the first end 72 a and the second end 72 b of the second chip breaker. Preferably, each of the first and second valleys 73, 74 has an increasing depth when viewed in a direction along the chip breaker from the first end 71 a, 72 a of the chip breaker toward the second end 71 b, 72 b of the chip breaker. In the illustrated embodiment, each of the first and second valleys 73, 74 has an increasing width w when viewed in a direction along the chip breaker from the first end 71 a, 72 a of the chip breaker toward the second end 71 b, 72 b of the chip breaker, where the width w of the valley 73, 74 is measured as the distance in a plane extending parallel to the longitudinal plane LP between a first longitudinal edge of the valley on a first side of the valley and a second longitudinal edge of the valley on an opposite second side of the valley.

[0062] Each of the first and second major cutting edges 31, 32 and each of the first and second minor cutting edges 41, 42 preferably has a nominal rake angle that is positive or zero. In the illustrated embodiment, the major cutting edges 31, 32 and minor cutting edges 41, 42 have positive nominal rake angles. Also, in the illustrated embodiment, the first and second ramping cutting edges 51, 52 have positive nominal rake angles.

[0063] A reinforcing land 9 in the form of a narrow chamfer may be disposed in a conventional manner on the first major surface 2 between one or more of the cutting edges 21, 22, 31, 32, 41, 42, 51, 52, 61-63 and the associated rake face. The reinforcing land 9 may have a negative, zero, or positive nominal rake angle.

[0064] The cutting insert 1 shown in Figures 1a to 1j is a single-sided, dual-use indexable cutting insert in which cutting edges are arranged only along the outer periphery of the first main surface 2, which means that the cutting insert 1 can be attached to two different index positions of a milling tool by rotating the cutting insert 1 by 180° about the central axis C. In this case, the second main surface 3, i.e., the bottom surface of the cutting insert, is preferably flat and configured to extend perpendicular to the central axis C. However, this type of single-sided, dual-use indexable cutting insert 1 can also have a profiled bottom surface.

[0065] 2a to 2j is a double-sided, four-way indexable cutting insert in which cutting edges are arranged along the outer periphery of the first main surface 2 and also along the outer periphery of the second main surface 3, meaning that the cutting insert 1 can be mounted at four different index positions on a milling tool. In this case, the first main surface 2 and the second main surface 3 are identical to each other within manufacturing tolerances, and the cutting edges arranged along the outer periphery of the second main surface 3 are identical to the above-mentioned cutting edges 21, 22, 31, 32, 41, 42, 51, 52, 61 to 64 arranged along the outer periphery of the first main surface 2 within manufacturing tolerances.

[0066] 3-6 show a milling tool 80 in the form of an end mill suitable for use in ramping and pocketing. The milling tool 80 includes an elongated tool body 81 and is configured to rotate about a rotation axis 82. The tool body 81 has a rear end 81a and an opposite front end 81b. A longitudinal axis 83 of the tool body 81 extends between the rear end 81a and the front end 81b of the tool body, where the longitudinal axis 83 coincides with the rotation axis 82 of the milling tool 80. At the rear end 81a, the tool body 81 is attached to a rotating spindle of a milling machine, for example, by a tool holder. At the front end 81b, the tool body 81 includes an insert seat 84 configured to receive a cutting insert 1. In the illustrated example, the tool body 81 includes three insert seats 84 evenly distributed around the longitudinal axis 83 of the tool body and configured to receive a cutting insert 1. However, the tool body 81 may alternatively include any other suitable number of insert seats 84, particularly depending on the diameter of the tool body. A smaller diameter tool body may include, for example, two insert seats, while a larger diameter tool body may include four or more insert seats.

[0067] The cutting inserts 1 are mounted in respective insert seats 84 of the tool body 81. In the embodiment shown in Figures 3-6, the milling tool 80 includes cutting inserts 1 of the type shown in Figures 1a-1j. Each cutting insert 1 is configured to be removably mounted in its associated insert seat 84. In the illustrated embodiment, each cutting insert 1 is secured to its associated insert seat 84 by a fastening element 6 in the form of a screw, which extends through the through hole 5 of the cutting insert 1 and engages with a threaded hole 85 (see Figure 6) in the tangential support surface 86 of the insert seat. The insert seat 84 also includes a radial support surface 87 and an axial support surface 88. The cutting insert 1 includes a radial abutment surface 7 on each of the first and third major side surfaces 11, 13, and an axial abutment surface 8 on each of the second and fourth major side surfaces 12, 14. The radial and axial abutment surfaces 7, 8 of the first and second major side surfaces 11, 12 form a first pair of abutment surfaces, and the radial and axial abutment surfaces 7, 8 of the third and fourth major side surfaces 13, 14 form a second pair of abutment surfaces. The radial and axial abutment surfaces 7, 8 of each pair are preferably disposed at an acute angle relative to one another when viewed in a cross section of the cutting insert 1 parallel to the median plane MP, in which case the radial and axial support surfaces 87, 88 of each insert seat 84 are disposed at corresponding acute angles relative to one another.

[0068] When mounted in the insert seat 84, the cutting insert 1 is positioned so that the second main surface 3, or at least a portion thereof, abuts against the tangential support surface 86 of the insert seat, and the radial and axial abutment surfaces 7, 8 of one of the pair abut against the radial and axial support surfaces 87, 88 of the insert seat, respectively. When the cutting insert 1 is positioned so that the second pair of radial and axial abutment surfaces 7, 8 abut against the radial and axial support surfaces 87, 88, the first side cutting edge 21, the first curved corner cutting edge 61, the first major cutting edge 31, the first minor cutting edge 41, and the first ramping cutting edge 51 are in effective positions and constitute effective cutting edges. When the cutting insert 1 is positioned so that the first pair of radial and axial abutment surfaces 7, 8 abut against the radial and axial support surfaces 87, 88, the second side cutting edge 22, the third curved corner cutting edge 63, the second main cutting edge 32, the second minor cutting edge 42, and the second ramping cutting edge 52 are in effective positions and constitute effective cutting edges.

[0069] In ramping, the effective main cutting edges 31, 32, the effective ramping edges 51, 52, and possibly also the effective curved corner cutting edges 61, 63, perform the main cut on the workpiece, while the surface roughening cutting edge areas 43 of the effective minor cutting edges 41, 42 only shallowly cut and smooth the surface.

[0070] The present invention is of course in no way limited to the embodiments described above: on the contrary, it will be obvious to those skilled in the art that there are many possibilities for modifying them without departing from the basic idea of ​​the invention as defined in the appended claims.

Claims

1. 1. A cutting insert for use in high feed milling, comprising: - first and second main surfaces (2, 3) located on opposite sides of said cutting insert (1) and serving as the top and bottom surfaces of said cutting insert; a central axis (C) extending between said first main surface (2) and said second main surface (3), said cutting insert (1) being rotationally symmetric through 180° about said central axis (C); a median plane (MP) extending perpendicular to said central axis (C) midway between said first main surface (2) and said second main surface (3); a peripheral flank (10) extending around said cutting insert (1) between said first main surface (2) and said second main surface (3) and comprising a first main side surface (11), a second main side surface (12), a third main side surface (13), a fourth main side surface (14), a first corner side surface (15), a second corner side surface (16), a third corner side surface (17) and a fourth corner side surface (18), the first corner side (15) is disposed between the first major side (11) and the second major side (12); the second corner side (16) is disposed between the second major side (12) and the third major side (13); the third corner side (17) is disposed between the third major side (13) and the fourth major side (14); the fourth corner side (18) is disposed between the first major side (11) and the fourth major side (14); the first major side (11) and the third major side (13) form a first opposing major side pair; the second major side (12) and the fourth major side (14) form a second opposing major side pair; a peripheral flank (10); a first side cutting edge (21) formed at the intersection of said first main side surface (11) and said first main surface (2); a second side cutting edge (22) formed at the intersection of said third main side surface (13) and said first main surface (2); a first major cutting edge (31), a first minor cutting edge (41) and a first ramping cutting edge (51) formed at a line of intersection of the second major side surface (12) and the first major surface (2), the first minor cutting edge (41) being arranged between the first major cutting edge (31) and the first ramping cutting edge (51); a second major cutting edge (32), a second minor cutting edge (42) and a second ramping cutting edge (52) formed at a line of intersection of the fourth major side surface (14) and the first major surface (2), the second minor cutting edge (42) being arranged between the second major cutting edge (32) and the second ramping cutting edge (52); a first curved corner cutting edge (61) formed at the intersection of the first corner side surface (15) and the first main surface (2), the first curved corner cutting edge (61) being located between the first side cutting edge (21) and the first main cutting edge (31); a second curved corner cutting edge (62) formed at the intersection of the second corner flank (16) and the first main face (2), the second curved corner cutting edge (62) being located between the first ramping cutting edge (51) and the second flank cutting edge (22); a third curved corner cutting edge (63) formed at the intersection of the third corner side surface (17) and the first main surface (2), the third curved corner cutting edge (63) being located between the second side cutting edge (22) and the second main cutting edge (32); a fourth curved corner cutting edge (64) formed at the intersection of the fourth corner side surface (18) and the first main surface (2), the fourth curved corner cutting edge (64) being located between the second ramping cutting edge (52) and the first side cutting edge (21); Equipped with the shortest distance (d1) between the opposing first main cutting edge (31) and the opposing second main cutting edge (32) is equal to or longer than the shortest distance (d2) between the opposing first side cutting edge (21) and the opposing second side cutting edge (22); the first major cutting edge (31) has a first end (31a) connected to the first minor cutting edge (41) and a second end (31b) connected to the first curved corner cutting edge (61); the second major cutting edge (32) has a first end (32a) connected to the second minor cutting edge (42) and a second end (32b) connected to the third curved corner cutting edge (63); and each of the first and second major cutting edges (31, 32) has one or more inclined portions between its first end (31a, 32a) and second end (31b, 32b) having one or more inclinations such that its second end (31b, 32b) is located closer to the median plane (MP) than its first end (31a, 32a); the first ramping cutting edge (51) has a first end (51a) connected to the first minor cutting edge (41) and a second end (51b) connected to the second curved corner cutting edge (62); the second ramping cutting edge (52) has a first end (52a) connected to the second minor cutting edge (42) and a second end (52b) connected to the fourth curved corner cutting edge (64); and each of the first and second ramping cutting edges (51, 52) has one or more slopes between its first end (51a, 52a) and second end (51b, 52b) that have one or more slopes such that its second end (51b, 52b) is located closer to the median plane (MP) than its first end (51a, 52a); the first main cutting edge (31) and the first ramping cutting edge (51) extend at an obtuse angle (α) relative to one another when viewed in a plan view of the cutting insert (1), and the second main cutting edge (32) and the second ramping cutting edge (52) extend at a corresponding obtuse angle (α) relative to one another when viewed in a plan view of the cutting insert (1); It is a cutting insert, The cutting insert is characterized in that the second ends (31b, 32b) of the first and second main cutting edges (31, 32), respectively, are positioned closer to the median plane (MP) than the second ends (51b, 52b) of the first and second ramping cutting edges (51, 52), respectively.

2. The cutting insert according to claim 1, wherein the obtuse angle (α) is between 95° and 160°.

3. A cutting insert as described in claim 2, characterized in that the obtuse angle (α) is 100° to 125°.

4. A cutting insert as described in claim 3, characterized in that the obtuse angle (α) is 112°±5°.

5. 5. The cutting insert according to claim 1, wherein each of the first and second main cutting edges (31, 32) is inclined towards the median plane (MP) along a major part of its length when going from its first end (31 a, 32 a) to its second end (31 b, 32 b) or along its entire length from its first end (31 a, 32 a) to its second end (31 b, 32 b).

6. 6. The cutting insert according to claim 5, characterized in that each of the first and second main cutting edges (31, 32) is inclined towards the median plane (MP) with a constant or increasing inclination when viewed along its entire length from its first end (31 a, 32 a) to its second end (31 b, 32 b).

7. 7. The cutting insert according to claim 1, wherein the first main cutting edge (31) extends along a straight or convex line, or along a line that is a series of one or more straight lines combined with one or more convex lines, when viewed in a viewing direction parallel to the median plane (MP) and perpendicular to a first straight line of an intersection line (L1) where the first and second ends (31 a, 31 b) of the first main cutting edge are intersected; and the second main cutting edge (32) extends along a straight or convex line, or along a line that is a series of one or more straight lines combined with one or more convex lines, when viewed in a viewing direction parallel to the median plane (MP) and perpendicular to a second straight line of an intersection line (L2) where the first and second ends (32 a, 32 b) of the second main cutting edge are intersected.

8. 8. The cutting insert according to claim 1, wherein each of the first and second ramping cutting edges (51, 52) is inclined towards the median plane (MP) along its entire length from its first end (51 a, 52 a) to its second end (51 b, 52 b).

9. - the first curved corner cutting edge (61) has a first end (61a) connected to the first main cutting edge (31) and a second end (61b) connected to the first side cutting edge (21), and the third curved corner cutting edge (63) has a first end (63a) connected to the second main cutting edge (32) and a second end (63b) connected to the second side cutting edge (22); - each of said first and third curved corner cutting edges (61, 63) has one or more inclined portions between its first end (61a, 63a) and its second end (61b, 63b) with one or more inclinations such that its second end (61b, 63b) is located closer to said median plane (MP) than its first end (61a, 63a); The cutting insert according to any one of claims 1 to 8, characterized in that it comprises a tungsten carbide.

10. 10. The cutting insert according to claim 9, characterized in that each of the first and third curved corner cutting edges (61, 63) is inclined towards the median plane (MP) along its entire length from its first end (61 a, 63 a) to its second end (61 b, 63 b).

11. 11. The cutting insert according to claim 10, characterized in that each of the first and third curved corner cutting edges (61, 63) is inclined towards the median plane (MP) with a constant or increasing inclination when viewed along its entire length from its first end (61 a, 63 a) to its second end (61 b, 63 b).

12. 12. The cutting insert according to claim 11, wherein the first curved corner cutting edge (61) has, at every point along the first curved corner cutting edge (61), a slope that is equal to or greater than the minimum slope of the first major cutting edge (31) at every point along the first curved corner cutting edge (61), and the third curved corner cutting edge (63) has, at every point along the third curved corner cutting edge (63), a slope that is equal to or greater than the minimum slope of the second major cutting edge (32) at every point along the second major cutting edge (32).

13. 13. The cutting insert according to claim 1, wherein at every point along the first curved corner cutting edge (61), the distance between the first curved corner cutting edge (61) and the median plane (MP) is equal to or less than the distance between the second end (31 b) of the first major cutting edge (31) and the median plane (MP), and at every point along the third curved corner cutting edge (63), the distance between the third curved corner cutting edge (63) and the median plane (MP) is equal to or less than the distance between the second end (32 b) of the second major cutting edge (32) and the median plane (MP).

14. The first main cutting edge (31) and the first curved corner cutting edge (61) are configured such that, when viewed in a viewing direction parallel to the median plane (MP) and perpendicular to a first straight line of an intersection line (L1) intersecting the first and second ends (31a, 31b) of the first main cutting edge (31), the first curved corner cutting edge (61) is located between the median plane (MP) and any tangent that can be drawn to a point along the first main cutting edge (31), and the second main cutting edge (32) and 14. The cutting insert according to claim 1, wherein the third curved corner cutting edge (63) is configured such that, when viewed in a direction parallel to the median plane (MP) and perpendicular to a second straight line of an intersection line (L2) intersecting the first and second ends (32a, 32b) of the second main cutting edge (32), the third curved corner cutting edge (63) is positioned between the median plane (MP) and any tangent line that can be drawn to a point along the second main cutting edge (32).

15. a first chip breaker (71) associated with said first main cutting edge (31) is formed in said first main face (2) and extends in said first main face (2) along at least a portion of said first main cutting edge (31) or along the entire length of said first main cutting edge (31), said first chip breaker (71) having a first end (71a) facing towards said first ramping cutting edge (51) and an opposite second end (71b) facing towards said first main side face (11); a second chip breaker (72) associated with the second main cutting edge (32) is formed in the first main face (2) and extends along at least a portion of the second main cutting edge (32) or along the entire length of the second main cutting edge (32) in the first main face (2), the second chip breaker (72) having a first end (72a) facing towards the second ramping cutting edge (52) and an opposite second end (72b) facing towards the third main side face (13); A cutting insert according to any one of claims 1 to 14, characterized in that it comprises a tungsten carbide.

16. A cutting insert as described in claim 15, characterized in that the first chip breaker (71) is also associated with the first curved corner cutting edge (61) and configured to extend along the first curved corner cutting edge (61).

17. A cutting insert as described in claim 15 or 16, characterized in that the second chip breaker (72) is also associated with the third curved corner cutting edge (63) and is configured to extend along the third curved corner cutting edge (63).

18. - the first curved corner cutting edge (61) has a first end (61a) connected to the first main cutting edge (31) and a second end (61b) connected to the first side cutting edge (21), and the third curved corner cutting edge (63) has a first end (63a) connected to the second main cutting edge (32) and a second end (63b) connected to the second side cutting edge (22); the second end (71b) of the first chip breaker (71) is adjacent to the second end (61b) of the first curved corner cutting edge (61), and the second end (72b) of the second chip breaker (72) is adjacent to the second end (63b) of the third curved corner cutting edge (63). The cutting insert according to any one of claims 15 to 17, characterized in that

19. - said first chip breaker (71) has a U-shaped or V-shaped profile when viewed in cross section of said first chip breaker (71) parallel to a longitudinal plane (LP) of said cutting insert containing said central axis (C), extending perpendicular to said median plane (MP) midway between said first main side (2) and said third main side (3), thereby forming an elongated first valley (73) in said first main side (2) extending between said first end (71 a) and said second end (71 b) of said first chip breaker (71); said second chip breaker (72) has a U-shaped or V-shaped profile when viewed in cross section of said second chip breaker (72) parallel to said longitudinal plane (LP), thereby forming in said first main face (2) an elongated second valley (74) extending between said first end (72a) and said second end (72b) of said second chip breaker (72); The cutting insert according to any one of claims 15 to 18, characterized in that

20. 20. The cutting insert according to claim 19, wherein the first valleys (73) have an increasing depth when viewed in a direction along the first chip breaker (71) from the first end (71 a) of the first chip breaker (71) toward the second end (71 b) of the first chip breaker (71), and the second valleys (74) have an increasing depth when viewed in a direction along the second chip breaker (72) from the first end (72 a) of the second chip breaker (72) toward the second end (72 b) of the second chip breaker (72).

21. 21. The cutting insert according to claim 19 or 20, characterized in that the first valley (73) has a width (w) that increases when viewed in a direction along the first chip breaker (71) from the first end (71 a) of the first chip breaker (71) towards the second end (71 b) of the first chip breaker (71), and the second valley (74) has a width (w) that increases when viewed in a direction along the second chip breaker (72) from the first end (72 a) of the second chip breaker (72) towards the second end (72 b) of the second chip breaker (72).

22. 22. The cutting insert according to any one of claims 1 to 21, characterized in that each of the first and second major cutting edges (31, 32) and each of the first and second minor cutting edges (41, 42) also have a nominal rake angle that is positive or zero.

23. 23. The cutting insert according to any one of claims 1 to 22, characterized in that the cutting insert (1) is a one-sided, two-way indexable cutting insert, the second main surface (3) being flat and extending perpendicular to the central axis (C).

24. A high feed milling tool comprising at least one cutting insert (1) according to any one of claims 1 to 23.

Images