Double-sided cutting inserts and milling tools

Abstract

Provided is a double-sided cutting insert for use in milling, the double-sided cutting insert comprising: a first major surface (2) and a second major surface (3); a peripheral surface (10) disposed between the major surfaces (2, 3) and including a first major side surface (11); a first main cutting edge (21) formed at an intersection between the first major side surface and the first major surface; a second main cutting edge (22) formed at an intersection between the first major side surface and the second major surface; first and second inclined side surfaces (31, 32) formed on the first major side surface (11) and inclined towards each other to form a depression (D1) on the first major side surface; and a chip deflector (50) formed on the first major side surface as a protrusion spanning the depression (D1) and including a chip deflection surface (51) configured to deflect chips impinging on the first major side surface away from the depression.

Description

[Technical Field]

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

[0002] A milling tool is a rotary cutting tool that may include one or more cutting inserts removably mounted in corresponding insert seats in the tool body of the milling tool. The cutting inserts may have a polygonal basic shape and may include several identical cutting edges, allowing each individual cutting insert to be pivoted to different working positions. When a cutting edge of a cutting insert is worn, the cutting insert may be relocated in its seat and another cutting edge may be attached in a cutting action position in the new working position. Such a cutting insert may have the form of, for example, a double-sided cutting insert having one or more major cutting edges located along the periphery of a first major surface of the cutting insert and one or more corresponding major cutting edges located along the periphery of an opposite second major surface of the cutting insert, the first and second major surfaces serving as the top and bottom surfaces of the cutting insert.

[0003] Double-sided cutting inserts of the type described above have been known for some time in a variety of configurations, and examples of such cutting inserts are disclosed, for example, in U.S. Patent Application Publication No. 2014 / 0212229 and European Patent Application Publication No. 2596889. Summary of the Invention

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

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

[0006] The double-sided cutting insert according to the invention has a polygonal basic shape and can be swiveled into different working positions, - 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, each of the first and second major surfaces having a polygonal shape as seen in a plan view of the cutting insert; a central axis extending between the first major surface and the second major surface; a peripheral surface extending around the cutting insert between the first major surface and the second major surface and including at least a first major side portion forming a first peripheral side of the cutting insert; a first main cutting edge formed at an intersection between the first major side portion and the first main surface; a second main cutting edge formed at an intersection between the first main side portion and the second main surface; a first inclined side surface and a second inclined side surface formed on the first main side surface portion, the first inclined side surface being located between the first main side surface and the second inclined side surface and configured to form a clearance surface for the first main cutting edge in a first working position of the working positions, and the second inclined side surface being located between the second main side surface and the first inclined side surface and configured to form a clearance surface for the second main cutting edge in a second working position of the working positions, the first inclined side surface extending from a first edge of the first inclined side surface facing the first main side surface to the second inclined side surface a first inclined side surface and a second inclined side surface, the first inclined side surface and the second inclined side surface being inclined inwardly as viewed in a direction from a first edge of the second inclined side surface facing the second main surface toward a second edge of the second inclined side surface facing the first inclined side surface, the first inclined side surface and the second inclined side surface being opposite each other and inclined toward each other to form a recess on the first main side surface between the first and second main cutting edges; a first chip deflection member formed on the first major side surface as a protrusion extending across a recess formed by the first and second inclined side surfaces, the first chip deflection member having a first end facing the first major cutting edge, an opposite second end facing the second major cutting edge, and at least a first chip deflection surface extending between the first and second ends and configured to deflect chips striking the first major side surface away from the recess, each of the first and second inclined side surfaces including a first minor surface located on the first side of the first chip deflection member and a second minor surface located on the opposite second side of the first chip deflection member.

[0007] The first and second minor surfaces of the first inclined side surface are preferably arranged in the same plane. The first and second minor surfaces of the second inclined side surface are preferably arranged in the same plane.

[0008] The above-mentioned polygonal basic shape of the cutting insert implies that the cutting insert, as viewed in the circumferential direction, has several distinct and separate side surfaces that are connected to and continuous with each other via intermediate corner regions that form the circumferential surface of the cutting insert. Thus, the polygonal basic shape of the cutting insert implies that the body of the cutting insert, as viewed in a cross section perpendicular to the central axis of the cutting insert, has a non-circular, non-elliptical shape.

[0009] When the cutting insert is mounted in the insert seat in the tool body of the milling tool and the cutting insert is positioned in the first working position, the first main cutting edge is positioned to form an active main cutting edge in the milling tool and the first inclined side surface is positioned to form a clearance surface for the active main cutting edge. When the cutting insert is mounted in the insert seat and the cutting insert is positioned in the second working position, the second main cutting edge is positioned to form an active main cutting edge in the milling tool and the second inclined side surface is positioned to form a clearance surface for the active main cutting edge. In both of these working positions, the first major side surface, having the first and second inclined sides, faces radially outward on the tool body, implying that chips generated by the rotary milling tool during milling of a workpiece may scratch the first major side surface during part of the rotation of the working main cutting edge when it is in contact with the workpiece, or that chips or chips formed by the working main cutting edge may strike the first major side surface at the moment the working main cutting edge loses contact with the workpiece. Chips striking the first major side surface may cause harmful erosion of the inclined side surface closest to the non-working main cutting edge and may also damage the non-working cutting edge. Damage to the non-working main cutting edge may reduce the useful life of the cutting insert and, in the worst case, may render the non-working main cutting edge unusable. If the inclined side surface closest to the non-working main cutting edge serves as an abutment surface for the cutting insert in another working position of the cutting insert and is configured to abut against a corresponding support surface in the insert seat in the tool body, extensive corrosion of this inclined side surface may cause the cutting insert to be improperly mounted in the insert seat when the cutting insert is subsequently positioned in a working position with the corroded inclined side surface as the working abutment surface. The chip deflector deflects chips striking the first major side surface portion away from the inclined side surface closest to the non-working main cutting edge, thereby reducing corrosion of this inclined side surface and reducing chip-induced damage to the non-working main cutting edge.

[0010] The central axis of the cutting insert extends between the center point of the first major surface and the center point of the second major surface. The center point refers to the center of mass or geometric center. The cutting insert may have a through hole extending centrally through the cutting insert between the first major surface and the second major surface, and the central axis of the through hole coincides with the central axis of the cutting insert.

[0011] According to one embodiment of the present invention, the first chip deflection member includes a second chip deflection surface and a third chip deflection surface disposed on either side of the first chip deflection surface, the second chip deflection surface being inclined outward from the first chip deflection surface and adjacent to the first minor surface of the first inclined side surface and the first minor surface of the second inclined side surface, and the third chip deflection surface being inclined outward from the first chip deflection surface and adjacent to the second minor surface of the first inclined side surface and the second minor surface of the second inclined side surface. The inclined second chip deflection surface and the inclined third chip deflection surface assist the first chip deflection surface in deflecting chips striking the first major side surface away from the recess formed by the first inclined side surface and the second inclined side surface.

[0012] In another embodiment of the present invention, the first chip deflection surface has a first longitudinal edge extending between the first end and the second end of the first chip deflection member and an opposite second longitudinal edge extending between the first end and the second end of the first chip deflection member; - the second chip deflection surface is adjacent to and extends all along the first longitudinal edge of the first chip deflection surface; The third chip deflection surface may be adjacent to and extend all along the second longitudinal edge of the first chip deflection surface, and the first, second and third chip deflection surfaces may thereby cover all of the external exposed side surfaces of the first chip deflection member.

[0013] To accommodate the shape of the recess formed by the first and second inclined sides, the first chip deflection surface may have a parallelogram shape, and the second and third chip deflection surfaces may be triangular.

[0014] According to another embodiment of the present invention, the first major side portion is rotationally symmetrical by 180 degrees about an imaginary reference axis that passes through a center point of the first major side portion and extends perpendicular to the central axis of the cutting insert.

[0015] In another embodiment of the present invention, - the flank surface formed by the first inclined side surface in said first working position is configured to serve as a secondary flank surface for the first main cutting edge, the first primary flank surface being formed on the first main side surface and being adjacent to the first main cutting edge and being located between the first main cutting edge and the first inclined side surface, thereby serving as a primary flank surface for the first main cutting edge in said first working position; the flank formed by the second inclined flank in the second working position is configured to serve as a secondary flank for the second main cutting edge, the second primary flank is formed on the first main flank portion, and the second primary flank is adjacent to the second main cutting edge and is located between the second main cutting edge and the second inclined flank, thereby serving as a primary flank for the second main cutting edge in the second working position. In this case, the first chip deflection surface is preferably adjacent to the first primary flank at the first end of the first chip deflector and the second primary flank at the second end of the first chip deflector, which implies that the first chip deflector extends into the gap between the first and second primary flanks formed by the recess. This allows the first chip deflection member to efficiently deflect chips striking the first major side portion away from the recess between the first primary relief surface and the second primary relief surface.

[0016] According to another embodiment of the present invention, the cutting insert has a central surface extending midway between the first and second major surfaces, perpendicular to the central axis of the cutting insert, and each of the first and second primary flank surfaces is perpendicular to this central surface as seen in a section spanning the first and second primary flank surfaces that is parallel to a central plane of the cutting insert containing the central axis of the cutting insert and the center point of the first major side portion. The first primary flank surface may alternatively be inclined outwardly as viewed in a direction from a first longitudinal edge of the first primary flank surface facing or coinciding with the first main cutting edge, toward an opposite second longitudinal edge of the first primary flank surface facing the first beveled side surface, and the second primary flank surface is inclined outwardly as viewed in a direction from a first longitudinal edge of the second primary flank surface facing or coinciding with the second main cutting edge, toward an opposite second longitudinal edge of the second primary flank surface facing the second beveled side surface. Both of these alternatives imply that the primary flank surface associated with the active main cutting edge significantly aids in chip evacuation of the cutting insert.

[0017] According to another embodiment of the present invention, the cutting insert includes a through hole extending centrally through the cutting insert between the first and second major surfaces, with the central axis of the through hole coinciding with the central axis of the cutting insert. In this case, the first chip deflector is preferably located in the center of the first major side surface, which implies that the first chip deflector is located on the first major side surface in a region where the wall thickness between the through hole and the first major side surface typically has its minimum value. The first chip deflector contributes to a local increase in the wall thickness between the through hole and the first major side surface, thereby acting as a reinforcement on the cutting insert. This reinforcement allows certain dimensions of the cutting insert to be reduced without jeopardizing its strength.

[0018] According to another embodiment of the invention, the first chip deflection surface is intersected by the above-mentioned mid-plane along a line of intersection extending entirely between the first and second ends of the first chip deflection member, thereby ensuring that the first chip deflection member effectively contributes to the reinforcement of the cutting insert over its entire length.

[0019] In another embodiment of the present invention, the peripheral surface includes a second major side portion that forms a second peripheral side of the cutting insert; a third major cutting edge is formed at an intersection between the second major side portion and the first major surface; a fourth main cutting edge is formed at an intersection between the second main side portion and the second main surface; a third inclined side surface and a fourth inclined side surface are formed on the second main side surface portion, the third inclined side surface being located between the first main surface and the fourth inclined side surface and configured to form a clearance surface for the third main cutting edge in a third working position of said working positions, the fourth inclined side surface being located between the second main surface and the third inclined side surface and configured to form a clearance surface for the fourth main cutting edge in a fourth working position of said working positions, the third inclined side surface extending from a first edge of the third inclined side surface facing the first main surface; the fourth beveled side surface is inclined inwardly as viewed in a direction toward an opposite second edge of the third beveled side surface facing the fourth beveled side surface, the fourth beveled side surface being inclined inwardly as viewed in a direction from a first edge of the fourth beveled side surface facing the second main surface toward an opposite second edge of the fourth beveled side surface facing the third beveled side surface, the third beveled side surface and the fourth beveled side surface being opposite and inclined toward each other, thereby forming a recess on the second main side surface between the third and fourth main cutting edges; the cutting insert includes a second chip deflection member formed on the second main side surface as a protrusion extending across a recess formed by the third and fourth inclined side surfaces, the second chip deflection member having a first end facing the third main cutting edge, an opposite second end facing the fourth main cutting edge, and at least a first chip deflection surface extending between the first and second ends of the second chip deflection member and configured to deflect chips impinging on the second main side surface away from the recess formed by the third and fourth inclined side surfaces; Each of the third and fourth inclined sides includes a first minor surface located on a first side of the second chip deflector and a second minor surface located on a second side opposite the second chip deflector. In this case, the cutting insert has at least four different working positions. By increasing the number of possible working positions for the cutting insert, the service life of the cutting insert also increases. To achieve a double-sided cutting insert with four or more working positions, the cutting insert is preferably rotationally symmetrical by 360 degrees / n about the central axis of the cutting insert, where n is an integer having a value of 2 or greater, preferably 2, 3, 4, 5, 6, 7, or 8.

[0020] According to another embodiment of the present invention, each of the inclined side surfaces serves as an abutment surface of the cutting insert in at least one working position of the cutting insert and is configured to abut against a corresponding support surface of the insert seat in the tool body of the milling tool when the cutting insert is mounted in the insert seat in the at least one working position. Thus, one and the same inclined side surface can serve as a clearance surface for the active main cutting edge in one working position of the cutting insert and as an abutment surface of the cutting insert in another working position of the cutting insert. Two inclined side surfaces on one and the same main side surface may be configured to jointly serve as an abutment surface of the cutting insert in several of the possible working positions of the cutting insert. However, two inclined side surfaces on one and the same main side surface may alternatively be configured to serve as an abutment surface of the cutting insert one at a time in different working positions of the cutting insert. To ensure good stability of contact between the abutment surface formed by one of the inclined side surfaces and the corresponding support surface of the insert seat in the tool body, it is preferred that the minor surfaces of the inclined side surfaces on both sides of the intermediate chip deflector be included together in the abutment surface. However, the abutment surface may alternatively comprise only one of the two minor surfaces of the inclined side surface.

[0021] According to another embodiment of the present invention, the cutting insert comprises: - a first curved corner cutting edge and a first surface-wiping cutting edge formed at an intersection between the peripheral surface and the first major surface, the first major cutting edge, the first curved corner cutting edge, and the first surface-wiping cutting edge being sequentially arranged such that the first curved corner cutting edge is located between the first major cutting edge and the first surface-wiping cutting edge; - a second curved corner cutting edge and a second surface-wiping cutting edge formed at an intersection between the peripheral surface and the second major surface, the second major cutting edge, the second curved corner cutting edge, and the second surface-wiping cutting edge being sequentially arranged such that the second curved corner cutting edge is located between the second major cutting edge and the second surface-wiping cutting edge; - a third curved corner cutting edge and a third surface-wiping cutting edge formed at an intersection between the peripheral surface and the first major surface, the third major cutting edge, the third curved corner cutting edge, and the third surface-wiping cutting edge being sequentially arranged such that the third curved corner cutting edge is located between the third major cutting edge and the third surface-wiping cutting edge; a fourth curved corner cutting edge and a fourth surface-wiping cutting edge formed at an intersection between the peripheral surface and the second main surface, wherein the fourth main cutting edge, the fourth curved corner cutting edge, and the fourth surface-wiping cutting edge are sequentially arranged such that the fourth curved corner cutting edge is located between the fourth main cutting edge and the fourth surface-wiping cutting edge. In this case, the cutting insert may have the form of a square shoulder milling insert or a face milling insert.

[0022] Further advantageous features of the double-sided cutting insert according to the invention will become apparent from the description that follows.

[0023] The invention also relates to a milling tool equipped with a cutting insert of the type described above.

[0024] Further advantageous features of the milling tool according to the invention will become apparent from the description that follows.

[0025] A specific description of embodiments of the invention, given by way of example, will now be given with reference to the accompanying drawings, in which: [Brief explanation of the drawings]

[0026] [Figure 1a]1A to 1C are perspective views of a double-sided cutting insert according to a first embodiment of the present invention, viewed from different directions. [Figure 1b] 1A to 1C are perspective views of a double-sided cutting insert according to a first embodiment of the present invention, viewed from different directions. [Figure 1c] 1A to 1C are perspective views of a double-sided cutting insert according to a first embodiment of the present invention, viewed from different directions. [Figure 1d] 1A to 1C are perspective views of a double-sided cutting insert according to a first embodiment of the present invention, viewed from different directions. [Figure 1e] FIG. 2 is a plan view from above of the cutting insert of FIGS. 1a to 1d. [Figure 1f] FIG. 2 is a plan view from below of the cutting insert of FIGS. 1a to 1d. [Figure 1g] FIG. 1c shows a cut along line Ig-Ig in FIG. 1e. [Figure 1h] FIG. 2 is a side view of the cutting insert of FIGS. 1a to 1d. [Figure 2a] 10A and 10B are perspective views of a double-sided cutting insert according to a second embodiment of the present invention, viewed from different directions. [Figure 2b] 10A and 10B are perspective views of a double-sided cutting insert according to a second embodiment of the present invention, viewed from different directions. [Figure 2c] 10A and 10B are perspective views of a double-sided cutting insert according to a second embodiment of the present invention, viewed from different directions. [Figure 2d] 10A and 10B are perspective views of a double-sided cutting insert according to a second embodiment of the present invention, viewed from different directions. [Figure 2e] FIG. 2B is a plan view from above of the cutting insert of FIGS. 2a to 2d. [Figure 2f] FIG. 2B is a plan view from below of the cutting insert of FIGS. 2a to 2d. [Figure 2g] FIG. 2c shows a cut along line IIg-IIg in FIG. 2e. [Figure 2h] FIG. 2B is a side view of the cutting insert of FIGS. 2a to 2d. [Figure 3] 3a and 3b are different perspective views of a double-sided cutting insert according to a third embodiment of the present invention; [Figure 3c] Top plan views of the cutting inserts of FIGS. 3a and 3b. [Figure 3d] Bottom plan views of the cutting inserts of FIGS. 3a and 3b. [Figure 3e] A view showing a cut portion along line IIIe-IIIe of FIG. 3c. [Figure 3f] Side views of the cutting inserts of FIGS. 3a and 3b. [Figure 4] Side view of a milling tool provided with a cutting insert according to the embodiment shown in FIGS. 1a to FIG. 1h. [Figure 5] Perspective view of the milling tool of FIG. 4. [Figure 6] Perspective view of the milling tool of FIG. 4 from another direction. [Figure 7] Perspective view corresponding to FIG. 6 in a state where the cutting insert is removed from the insert seat in the tool body of the milling tool.

Best Mode for Carrying Out the Invention

[0027] Three different embodiments of the double-sided cutting inserts 1, 1', 1'' according to the present invention are shown in FIGS. 1a to FIG. 1h, FIGS. 2a to FIG. 2h, and FIGS. 3a to FIG. 3f. The cutting inserts 1, 1', 1'' are configured to be used in milling operations and are configured to be used in a milling tool, for example, a milling tool 80 of the type shown in FIGS. 4 to FIG. 7.

[0028] The cutting insert 1, 1', 1" has a polygonal basic shape and can be pivoted to different working positions. The cutting insert 1, 1', 1" comprises a first main surface 2 and a second main surface 3, which are arranged on opposite sides of the cutting insert and serve as the top and bottom surfaces of the cutting insert. The first main surface 2 and the second main surface 3 have a polygonal, or at least essentially polygonal, shape as seen in a plan view of the cutting insert 1, 1', 1". The cutting insert has a central axis C extending between the first main surface 2 and the second main surface 3. A central plane MP, which constitutes an imaginary plane, extends perpendicular to the central axis C midway between the first main surface 2 and the second main surface 3, as shown in Figures 1h, 2h, and 3f.

[0029] In the illustrated embodiment, the cutting insert 1, 1', 1" comprises a through hole 5, which extends centrally through 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, e.g., in the form of a screw (see FIGS. 4-7), by which the cutting insert can be removably fixed in an insert seat 84 of a milling tool 80. A central axis C of the cutting insert 1, 1', 1" coincides with the central axis of the through hole 5. The cutting insert 1, 1', 1" may alternatively be devoid of a through hole 5, and the cutting insert is configured to be removably fixed in an insert seat of a milling tool by suitable fastening means.

[0030] A peripheral flank 10 extends around the cutting insert 1, 1', 1'' between the first major surface 2 and the second major surface 3. The peripheral flank 10 comprises a first major side surface 11 forming a first peripheral side surface of the cutting insert. The first major side surface 11 is rotationally symmetrical by 180 degrees about an imaginary reference axis A1 (see Figures 1h, 2h, and 3f) that passes through a center point P1 of the first major side surface 11 and extends perpendicular to the central axis C of the cutting insert. A first main cutting edge 21 is formed at the intersection between the first major side surface 11 and the first major surface 2, and a second main cutting edge 22 is formed at the intersection between the first major side surface 11 and the second major surface 3.

[0031] The first inclined side surface 31 and the second inclined side surface 32 are formed on the first main side surface portion 11 between the first main cutting edge 21 and the second main cutting edge 22. The first inclined side surface 31 is located between the first main surface 2 and the second inclined side surface 32 and is configured to form a clearance surface for the first main cutting edge 21 in a first working position of the above-mentioned working positions. The second inclined side surface 32 is located between the second main surface 3 and the first inclined side surface 31 and is configured to form a clearance surface for the second main cutting edge 22 in a second working position of the above-mentioned working positions. The first inclined side surface 31 slopes inward as viewed in a direction from a first edge 31 a of the first inclined side surface 31 facing the first main surface 2 toward an opposite second edge 31 b of the first inclined side surface 31 facing the second inclined side surface 32. Correspondingly, the second inclined side surface 32 slopes inwardly as viewed in a direction from a first edge 32a of the second inclined side surface 32 facing the second major surface 3 to an opposite second edge 32b of the second inclined side surface 32 facing the first inclined side surface 31. The first and second inclined side surfaces 31, 32 are opposite and slope toward each other, thereby forming a recess D1 on the first major side surface portion 11 between the first and second main cutting edges 21, 22. In the embodiment shown in Figures 1a-1h, the recess D1 has a V-shaped profile as viewed in a section spanning the recess.

[0032] In the illustrated embodiment, the first angled side surface 31 is separated from the second angled side surface 32 by an elongated transition region 35, which is adjacent to the first angled side surface 31b and the second edge 32b of the second angled side surface and extends circumferentially about the peripheral surface 10. In the embodiment illustrated in Figures 1a-1h and 3a-3f, the transition region 35 extends obliquely relative to the central plane MP. In the embodiment illustrated in Figures 2a-2h, the transition region 35 extends parallel to the central plane MP.

[0033] The cutting insert 1, 1', 1'' comprises a first chip deflection member 50 formed on the first main side surface 11 as a protrusion extending across the recess D1, the first chip deflection member 50 having a first end 50a facing the first main cutting edge 21 and an opposite second end 50b facing the second main cutting edge 22. Both the first inclined side surface 31 and the second inclined side surface 32 are at least partially crossed by the first chip deflection member 50, the first inclined side surface 31 having a first minor surface 31' and a second minor surface 31'' located on either side of the first chip deflection member 50, and the second inclined side surface 32 having a corresponding first minor surface 32' and a second minor surface 32'' located on either side of the first chip deflection member 50. In the embodiment shown in Figures 1a to 1h and 2a to 2h, the first minor surface 31' and the second minor surface 31'' of the first inclined side surface 31 are both located in one plane, and the first minor surface 32' and the second minor surface 32'' of the second inclined side surface 32 are both located in another plane.

[0034] The first chip deflection member 50 includes a first chip deflection surface 51 extending between the first end 50a and the second end 50b of the first chip deflection member and configured to deflect chips striking the first major side portion 11 away from the recess D1. In the embodiment shown, the first chip deflection member 50 also includes a second chip deflection surface 52 and a third chip deflection surface 53 arranged on either side of the first chip deflection surface 51, the second chip deflection surface 52 being inclined outward from the first chip deflection surface 51 and adjacent to the first minor surface 31′ of the first inclined side surface 31 and the first minor surface 32′ of the second inclined side surface 32, and the third chip deflection surface 53 being inclined outward from the first chip deflection surface 51 and adjacent to the second minor surface 31″ of the first inclined side surface 31 and the second minor surface 32″ of the second inclined side surface 32. In the embodiment shown, the second chip deflecting surface 52 is adjacent to and extends entirely along the first longitudinal edge 51 a of the first chip deflecting surface 51, and the third chip deflecting surface 53 is adjacent to and extends entirely along the opposite second longitudinal edge 51 b of the first chip deflecting surface 51, each of these first and second longitudinal edges 51 a, 51 b extending between the first and second ends 50 a, 50 b of the first chip deflector 50. In the embodiment shown in Figures 1a-1h, the first chip deflecting surface 51 has a parallelogram shape, and the second and third chip deflecting surfaces 52, 53 are triangular.

[0035] The cutting insert 1, 1′, 1″ has a mid-plane CP (see FIGS. 1 h, 2 h, and 3 f) that contains the central axis C of the cutting insert and a midpoint P1 of the first major side portion 11. The first chip deflection member 50 is preferably disposed in the center of the first major side portion 11, whereby the first chip deflection member 51 is traversed by the mid-plane CP along a line of intersection L that extends entirely between the first end 50 a and the second end 50 b of the first chip deflection member 50.

[0036] 1a to 1h, the flank surface formed by the first inclined side surface 31 in the first working position is configured to serve as a secondary flank surface for the first main cutting edge 21, and the flank surface formed by the second inclined side surface 32 in the second working position is configured to serve as a secondary flank surface for the second main cutting edge 22, and the first primary flank surface 41 and the second primary flank surface 42 are formed on the first main side surface portion 11. The first primary flank surface 41 is adjacent to the first main cutting edge 21 and is located between the first main cutting edge 21 and the first inclined side surface 31, and thereby serves as a primary flank surface for the first main cutting edge 21 in the first working position. The second primary flank 42 is adjacent to the second main cutting edge 22 and is located between the second main cutting edge 22 and the second inclined flank 32, thereby serving as a primary flank for the second main cutting edge 22 in the second working position. In this case, the first chip deflection surface 51 preferably extends entirely between the first primary flank 41 and the second primary flank 42, and the first chip deflection surface 51 is adjacent to the first primary flank 41 at the first end 50 a of the first chip deflector 50 and the second primary flank 42 at the second end 50 b of the first chip deflector 50.

[0037] The first primary flank surface 41 has a first longitudinal edge 41 a facing or coinciding with the first major cutting edge 21, and an opposite second longitudinal edge 41 b facing the first beveled flank 31. Correspondingly, the second primary flank surface 42 has a first longitudinal edge 42 a facing or coinciding with the second major cutting edge 22, and an opposite second longitudinal edge 42 b facing the second beveled flank 32. In the embodiment shown in Figures 1a-1h, the first primary flank surface 41 is inclined outwardly as seen in the direction from this first longitudinal edge 41 a towards this second longitudinal edge 41 b, and the second primary flank surface 42 is inclined outwardly as seen in the direction from this first longitudinal edge 42 a towards this second longitudinal edge 42 b. Alternatively, the first primary flank 41 and the second primary flank 42 may be perpendicular to the central plane MP, as seen in the section spanning the first primary flank 41 and the second primary flank 42 that is parallel to the central plane CP of the cutting insert 1.

[0038] The cutting insert 1 shown in FIGS. 1a to 1h has the form of a square shoulder milling insert. In this case, the peripheral surface 10 includes a second major side portion 12 forming a second peripheral side surface of the cutting insert 1, a third major side portion 13 forming a third peripheral side surface of the cutting insert 1, and a fourth major side portion 14 forming a fourth peripheral side surface of the cutting insert 1. The first major side portion 11 and the second major side portion 12 form a first pair of opposing major side portions, and the third major side portion 13 and the fourth major side portion 14 form a second pair of opposing major side portions. Thus, the first major side portion 11 and the second major side portion 12 are located on opposite sides of the central axis C of the cutting insert 1. Correspondingly, the third major side portion 13 and the fourth major side portion 14 are located on opposite sides of the central axis C of the cutting insert 1.

[0039] The second major side portion 12 is identical to the first major side portion 11 within manufacturing tolerances and is rotationally symmetric by 180 degrees about an imaginary reference axis that passes through a center point P2 of the second major side portion 12 and extends perpendicular to the central axis C of the cutting insert. A third major cutting edge 23 is formed at the intersection between the second major side portion 12 and the first major surface 2, and a fourth major cutting edge 24 is formed at the intersection between the second major side portion 12 and the second major surface 3.

[0040] The third inclined side surface 33 and the fourth inclined side surface 34 are formed on the second major side surface portion 12 between the third major cutting edge 23 and the fourth major cutting edge 24. The third inclined side surface 33 is located between the first major surface 2 and the fourth inclined side surface 34 and is configured to form a clearance surface for the third major cutting edge 23 in a third working position of the above-mentioned working positions. The fourth inclined side surface 34 is located between the second major surface 3 and the third inclined side surface 33 and is configured to form a clearance surface for the fourth major cutting edge 24 in a fourth working position of the above-mentioned working positions. The third inclined side surface 33 slopes inward as viewed in a direction from a first edge 33 a of the third inclined side surface 33 facing the first major surface 2 to an opposite second edge 33 b of the third inclined side surface 33 facing the fourth inclined side surface 34. Correspondingly, the fourth inclined side surface 34 slopes inwardly as viewed in a direction from a first edge 34a of the fourth inclined side surface 34 facing the second major surface 3 to an opposite second edge 34b of the fourth inclined side surface 34 facing the third inclined side surface 33. The third inclined side surface 33 and the fourth inclined side surface 34 are opposite and slope toward each other, thereby forming a recess D2 on the second major side surface portion 12 between the third and fourth main cutting edges 23 and 24.

[0041] The cutting insert 1 includes a second chip deflector 60 formed on the second major side surface 12 as a protrusion extending across the recess D2, the second chip deflector 60 having a first end 60a facing the third major cutting edge 23 and an opposite second end 60b facing the fourth major cutting edge 24. Both the third inclined side surface 33 and the fourth inclined side surface 34 are traversed by the second chip deflector 60, the third inclined side surface 33 having a first minor surface 33′ and a second minor surface 33″ located on either side of the second chip deflector 60, and the fourth inclined side surface 34 having a corresponding first minor surface 34′ and a second minor surface 34″ located on either side of the second chip deflector 60. In the embodiment shown in Figures 1a to 1h, the first minor surface 33' and the second minor surface 33'' of the third inclined side surface 33 are both located in one plane, and the first minor surface 34' and the second minor surface 34'' of the fourth inclined side surface 34 are both located in another plane.

[0042] The second chip deflector 60 includes a first chip deflector surface 61 extending between the first end 60a and the second end 60b of the second chip deflector and configured to deflect chips striking the second major side portion 12 away from the recess D2. In the embodiment shown, the second chip deflection member 60 also includes a second chip deflection surface 62 and a third chip deflection surface 63 arranged on either side of the first chip deflection surface 61, the second chip deflection surface 62 being inclined outward from the first chip deflection surface 61 and adjacent to the first minor surface 33′ of the third inclined side surface 33 and the first minor surface 34′ of the fourth inclined side surface 34, and the third chip deflection surface 63 being inclined outward from the first chip deflection surface 61 and adjacent to the second minor surface 33″ of the third inclined side surface 33 and the second minor surface 34″ of the fourth inclined side surface 34.

[0043] 1a to 1h, the flank surface formed by the third inclined side surface 33 in the third working position is configured to serve as a secondary flank surface for the third main cutting edge 23, the flank surface formed by the fourth inclined side surface 34 in the fourth working position is configured to serve as a secondary flank surface for the fourth main cutting edge 24, and the third primary flank surface 43 and the fourth primary flank surface 44 are formed on the second main side surface portion 12. The third primary flank surface 43 is adjacent to the third main cutting edge 23 and is located between the third main cutting edge 23 and the third inclined side surface 33, and thereby serves as a primary flank surface for the third main cutting edge 23 in the third working position. The fourth primary clearance surface 44 is adjacent to the fourth main cutting edge 24 and is located between the fourth main cutting edge 24 and the fourth inclined side surface 34, thereby serving as a primary clearance surface for the fourth main cutting edge 24 in the fourth working position.

[0044] 1a-1h, peripheral surface 10 also includes a first corner side 15 located between first major side portion 11 and third major side portion 13, a second corner side 16 located between second major side portion 12 and third major side portion 13, a third corner side 17 located between third major side portion 13 and fourth major side portion 14, and a fourth corner side 18 located between fourth major side portion 14 and first major side portion 11. A first curved corner cutting edge 25a extends along first corner side 15 and is formed at the intersection between first corner side 15 and first major surface 2. A second curved corner cutting edge 25b extends along fourth corner side 18 and is formed at the intersection between fourth corner side 18 and second major surface 3. The third curved corner cutting edge 25c extends along the third corner side 17 and is formed at the intersection between the third corner side 17 and the first major surface 2. The fourth curved corner cutting edge 25d extends along the second corner side 16 and is formed at the intersection between the second corner side 16 and the second major surface 3. The first curved corner cutting edge 25a and the third curved corner cutting edge 25c are located on diagonally opposite sides of the first major surface 2, and the second curved corner cutting edge 25b and the fourth curved corner cutting edge 25d are located on diagonally opposite sides of the second major surface 3.

[0045] 1a-1h, first surface-wiping cutting edge 26a and first ramping cutting edge 27a each extend along a portion of third major side portion 13 and are formed at the intersection between third major side portion 13 and first major surface 2. Second surface-wiping cutting edge 26b and second ramping cutting edge 27b each extend along a portion of fourth major side portion 14 and are formed at the intersection between fourth major side portion 14 and second major surface 3. Third surface-wiping cutting edge 26c and third ramping cutting edge 27c each extend along another portion of fourth major side portion 14 and are formed at the intersection between fourth major side portion 14 and first major surface 2. The fourth surface-wiping cutting edge 26d and the fourth ramping cutting edge 27d each extend along another portion of the third major side portion 13 and are formed at the intersection between the third major side portion 13 and the second major surface 3.

[0046] The first curved corner cutting edge 25a extends between the first main cutting edge 21 and the first surface-wiping cutting edge 26a, the second curved corner cutting edge 25b extends between the second main cutting edge 22 and the second surface-wiping cutting edge 26b, the third curved corner cutting edge 25c extends between the third main cutting edge 23 and the third surface-wiping cutting edge 26c, and the fourth curved corner cutting edge 25d extends between the fourth main cutting edge 24 and the fourth surface-wiping cutting edge 26d. The first main cutting edge 21, the first curved corner cutting edge 25a, the first surface-wiping cutting edge 26a, and the first ramping cutting edge 27a form a first group of cutting edges that constitute the active cutting edges of the cutting insert 1 when the cutting insert is in the first working position. The second main cutting edge 22, the second curved corner cutting edge 25b, the second surface-wiping cutting edge 26b, and the second ramping cutting edge 27b form a second group of cutting edges that constitute the active cutting edges of the cutting insert 1 when the cutting insert is in the second working position. The third main cutting edge 23, the third curved corner cutting edge 25c, the third surface-wiping cutting edge 26c, and the third ramping cutting edge 27c form a third group of cutting edges that constitute the active cutting edges of the cutting insert 1 when the cutting insert is in the third working position. The fourth main cutting edge 24, the fourth curved corner cutting edge 25d, the fourth surface-wiping cutting edge 26d, and the fourth ramping cutting edge 27d form a fourth group of cutting edges that constitute the active cutting edges of the cutting insert 1 when the cutting insert is in the fourth working position. 1a-1h, portions 28 of the periphery of the first major surface 2 extending between the first ramping cutting edge 27a and the third main cutting edge 23, and between the third ramping cutting edge 27c and the first main cutting edge 21, constitute non-working transitions. Portions 29 of the periphery of the second major surface 3 extending between the fourth ramping cutting edge 27d and the second main cutting edge 22, and between the second ramping cutting edge 27b and the fourth main cutting edge 24 also constitute non-working transitions.

[0047] 4 to 7 show a milling tool 80 in the form of an end mill tool. 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, and 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, for example, via a tool holder, to a rotating spindle of a milling machine or the like. At the front end 81b, the tool body 81 includes insert seats 84 configured to receive cutting inserts 1. In the example shown, the tool body 81 includes four insert seats 84, which are uniformly distributed about the longitudinal axis 83 of the tool body and configured to receive cutting inserts 1. However, the tool body 81 may alternatively include any other suitable number of seats 84, depending, inter alia, on the diameter of the tool body: a smaller diameter tool body may include, for example, two seats, while a larger diameter tool body may include four or more seats.

[0048] The cutting inserts 1 are mounted in respective seats 84 in the tool body 81. In the embodiment shown in FIGS. 4-7, the milling tool 80 includes cutting inserts 1 of the type shown in FIGS. 1a-1h. Each cutting insert 1 is configured to be removably mounted in its associated seat 84. In the embodiment shown, each cutting insert 1 is secured to its associated seat 84 by a fastening element 6 in the form of a screw, which extends through a through hole 5 in the cutting insert 1 and engages with a threaded hole 85 (see FIG. 7) in a tangential support surface 86 of the seat. The seat 84 also includes a radial support surface 87 and an axial support surface 88. The cutting insert 1 includes at least one radial abutment surface on each of the first and second major side surfaces 11, 12 and at least one axial abutment surface 7a-7d on each of the third and fourth major side surfaces 13, 14.

[0049] A recess 89 is provided in the radial support surface 87, which recess 89 is configured to receive the chip deflectors 50, 60 which are now provided on the main side portions 11, 12 facing the radial support surface 87. The recess 89 is such that the chip deflectors 50, 60 are received in the recess 89 with play, i.e. without contacting any surface in the recess 89 or any other surface in the insert seat 84. In the embodiment shown in Figures 4 to 7, the recess 89 has the form of a groove extending across the radial support surface 87 and dividing the radial support surface 87 into two separate minor surfaces.

[0050] Each of the above-mentioned inclined side surfaces 31 to 34 of the cutting insert 1 shown in Figures 1a to 1h serves as a radial abutment surface of the cutting insert 1 in at least one working position of the cutting insert, and is configured to abut against a corresponding radial support surface 87 of the insert seat 84 in the tool body 81 when the cutting insert 1 is mounted in the insert seat 84 in this at least one working position. In the shown example, when the cutting insert 1 is in the first working position, the fourth oblique flank 34 abuts against the radial support surface 87 and the first axial abutment surface 7 a on the fourth main flank portion 14 abuts against the axial support surface 88; when the cutting insert 1 is in the second working position, the third oblique flank 33 abuts against the radial support surface 87 and the second axial abutment surface 7b on the third main flank portion 13 abuts against the axial support surface 88; when the cutting insert 1 is in the third working position, the second oblique flank 32 abuts against the radial support surface 87 and the third axial abutment surface 7c on the third main flank portion 13 abuts against the axial support surface 88; When the cutting insert 1 is in the fourth working position, the first inclined side surface 31 abuts against the radial support surface 87 and the fourth axial abutment surface 7d on the fourth main side surface portion 14 abuts against the axial support surface 88. Alternatively, the third inclined side surface 33 and the fourth inclined side surface 34 may be configured to jointly serve as abutment surfaces for the cutting insert 1 in the first and second working positions and to abut against the respective radial support surfaces 87, 87′ of the insert seat 84, and the first inclined side surface 31 and the second inclined side surface 32 are configured to jointly serve as abutment surfaces for the cutting insert 1 in the third and fourth working positions. As a further alternative, the second minor surface 33'' of the third inclined side surface 33 and the second minor surface 34'' of the fourth inclined side surface 34 may serve as radial abutment surfaces for the cutting insert 1 in the first and second working positions, one at a time, and the second minor surface 31'' of the first inclined side surface 31 and the second minor surface 32'' of the second inclined side surface 32 may serve as radial abutment surfaces for the cutting insert 1 in the third and fourth working positions, one at a time.

[0051] The second main surface 3 or at least a portion thereof abuts against the tangential support surface 86 in the insert seat 84 when the cutting insert 1 is in either the first working position or the third working position, whereas the first main surface 2 or at least a portion thereof abuts against the tangential support surface 86 when the cutting insert 1 is in either the second working position or the fourth working position.

[0052] The cutting insert 1, 1', 1'' of the present invention is preferably 360° / n rotationally symmetric about the central axis C of the cutting insert, where n is an integer having a value of 2 or greater, preferably 2, 3, 4, 5, 6, 7, or 8. In the embodiment shown in Figures 1a to 1h, the cutting insert 1 has a rectangular basic shape and is pivotable to four different working positions, and the cutting insert 1 is 180° rotationally symmetric about the central axis C of the cutting insert.

[0053] The cutting insert 1' shown in Figures 2a-2h has the form of a face milling insert, which has a square basic shape and can be pivoted to eight different working positions. In this case, the cutting insert 1' is rotationally symmetrical by 90 degrees about the central axis C of the cutting insert, which implies that the cutting insert 1' has four main side portions 11-14 that are identical to one another within manufacturing tolerances. Each main side portion 11-14 thus has a first main cutting edge 21 formed at the intersection between the main side portion 11-14 and the first main surface 2, and a second main cutting edge 22 formed at the intersection between the main side portion 11-14 and the second main surface 3. Furthermore, a first inclined side surface 31 and a second inclined side surface 32 are formed on each of the main side surfaces 11-14 between the first main cutting edge 21 and the second main cutting edge 22, and the first inclined side surface 31 and the second inclined side surface 32 on each of the main side surfaces 11-14 are inclined toward each other as described above to form a recess D1 on the main side surface 11-14 between the first main cutting edge 21 and the second main cutting edge 22. A chip deflector 50 of the type described above is formed on each of the main side surfaces 11-14 as a protrusion extending across the recess D1 on the main side surface 11-14.

[0054] 2a to 2h, a surface-wiping cutting edge 26' is located at the corner between each pair of adjacent first main cutting edges 21 and at the corner between each pair of adjacent second main cutting edges 22. Each surface-wiping cutting edge 26' is connected at each of its ends to the adjacent main cutting edge 21, 22 via a curved corner cutting edge 25'. Thus, each surface-wiping cutting edge 26' is connected to two curved corner cutting edges 25' located on either side of the surface-wiping cutting edge 26'.

[0055] In the embodiment shown in Figures 2a to 2h, each of the inclined side surfaces 31, 32 on the main side surfaces 11 to 14 is configured to serve as a radial abutment surface for the cutting insert 1' in at least one working position of the cutting insert, and is configured to serve as an axial abutment surface for the cutting insert 1' in at least one other working position of the cutting insert.

[0056] The cutting insert 1" shown in Figures 3a-3f has the form of a high-feed milling insert, which has an essentially triangular basic shape and can be pivoted to six different working positions. In this case, the cutting insert 1" is rotationally symmetrical by 120 degrees about the central axis C of the cutting insert, which implies that the cutting insert 1" has three main side portions 11-13 that are identical to one another within manufacturing tolerances. Each main side portion 11-13 thus has a first main cutting edge 21 formed at the intersection between the main side portion 11-13 and the first main surface 2, and a second main cutting edge 22 formed at the intersection between the main side portion 11-13 and the second main surface 3. Furthermore, a first inclined side surface 31 and a second inclined side surface 32 are formed on each of the main side surfaces 11-13 between the first main cutting edge 21 and the second main cutting edge 22, and the first inclined side surface 31 and the second inclined side surface 32 on each of the main side surfaces 11-13 are inclined toward each other as described above to form a recess D1 on the main side surface 11-13 between the first main cutting edge 21 and the second main cutting edge 22. A chip deflector 50 of the type described above is formed on each of the main side surfaces 11-13 as a protrusion extending across the recess D1 on the main side surface 11-13.

[0057] In the embodiment shown in Figures 3a to 3f, the first and second main cutting edges 21, 22 and the main flanks 11 to 13 have a convex shape as seen in the circumferential direction of the cutting insert 1''.

[0058] In the embodiment shown in Figures 3a to 3f, a curved corner cutting edge 25'' is located at the corner between each pair of adjacent first main cutting edges 21 and at the corner between each pair of adjacent second main cutting edges 22. Thus, each main cutting edge 21, 22 is connected at each of its ends to the adjacent main cutting edge 21, 22 via the curved corner cutting edge 25''.

[0059] The present invention is, of course, in no way limited to the embodiments described above. On the contrary, many possibilities for modification of the present invention will become apparent to those skilled in the art without departing from the basic concept thereof as defined in the appended claims.

Claims

1. A double-sided cutting insert for use in milling, said cutting insert (1, 1', 1'') having a polygonal basic shape and being swivelable into a plurality of different working positions, a first main surface (2) and a second main surface (3) disposed on either side of the cutting insert (1; 1'; 1'') and serving as a top surface and a bottom surface of the cutting insert, each of the first main surface (2) and the second main surface (3) having a polygonal shape as seen in a plan view of the cutting insert (1; 1'; 1''); a central axis (C) extending between the first main surface (2) and the second main surface (3); a peripheral surface (10) extending around the cutting insert (1; 1'; 1'') between the first main surface (2) and the second main surface (3) and including at least a first major side portion (11) forming a first peripheral side surface of the cutting insert; a first main cutting edge (21) formed at the intersection between the first main side portion (11) and the first main surface (2); a second main cutting edge (22) formed at the intersection between the first main side portion (11) and the second main surface (3); a first inclined side surface (31) and a second inclined side surface (32) formed on the first main side surface portion (11), the first inclined side surface (31) being located between the first main surface (2) and the second inclined side surface (32) and configured to form a clearance surface for the first main cutting edge (21) in a first working position among the working positions, and the second inclined side surface (32) being located between the second main surface (3) and the first inclined side surface (31) and configured to form a clearance surface for the second main cutting edge (22) in a second working position among the working positions, the first inclined side surface (31) being located from a first edge (31 a) of the first inclined side surface (31) facing the first main surface (2) to the second inclined side surface (32); a first inclined side surface (31) and a second inclined side surface (32) that are inclined inwardly as viewed in a direction toward a second edge (31b) opposite the first inclined side surface (31), the second inclined side surface (32) being inclined inwardly as viewed in a direction from a first edge (32a) of the second inclined side surface (32) facing the second main surface (3) toward a second edge (32b) opposite the second inclined side surface (32) that faces the first inclined side surface (31), the first inclined side surface (31) and the second inclined side surface (32) being located on opposite sides and inclined toward each other, thereby forming a recess (D1) on the first main side surface portion (11) between the first main cutting edge (21) and the second main cutting edge (22); the cutting insert (1;1';1'') comprises a first chip deflector (50) formed on the first main side surface (11) as a protrusion extending across the depression (D1) formed by the first inclined side surface (31) and the second inclined side surface (32), the first chip deflector (50) having a first end (50a) facing the first main cutting edge (21), an opposite second end (50b) facing the second main cutting edge (22), and at least a first chip deflection surface (51) extending between the first end (50a) and the second end (50b) and configured to deflect chips striking the first main side surface (11) away from the depression (D1); each of the first inclined side surface (31) and the second inclined side surface (32) includes a first minor surface (31', 32') located on a first side surface of the first chip deflection member (50) and a second minor surface (31'', 32'') located on a second side surface opposite the first chip deflection member (50).

2. 2. The double-sided cutting insert according to claim 1, wherein the first chip deflecting member (50) includes a second chip deflecting surface (52) and a third chip deflecting surface (53) arranged on both sides of the first chip deflecting surface (51), the second chip deflecting surface (52) is inclined outward from the first chip deflecting surface (51) and is adjacent to the first minor surface (31′) of the first inclined side surface (31) and the first minor surface (32′) of the second inclined side surface (32), and the third chip deflecting surface (53) is inclined outward from the first chip deflecting surface (51) and is adjacent to the second minor surface (31″) of the first inclined side surface (31) and the second minor surface (32″) of the second inclined side surface (32).

3. the first chip deflection surface (51) has a first longitudinal edge (51a) extending between the first end (50a) and the second end (50b) of the first chip deflection member (50), and an opposite second longitudinal edge (51b) extending between the first end (50a) and the second end (50b) of the first chip deflection member (50); the second chip deflection surface (52) is adjacent to and extends entirely along the first longitudinal edge (51a) of the first chip deflection surface (51); 3. The double-sided cutting insert according to claim 2, characterized in that the third chip deflecting surface (53) is adjacent to and extends all along the second longitudinal edge (51b) of the first chip deflecting surface (51).

4. 4. The double-sided cutting insert according to claim 2 or 3, characterized in that the first chip deflection surface (51) has the shape of a parallelogram and the second chip deflection surface (52) and the third chip deflection surface (53) are triangular.

5. 5. The double-sided cutting insert according to claim 1, wherein the first main side surface portion (11) is rotationally symmetrical by 180 degrees about an imaginary reference axis (A1) that passes through a center point (P1) of the first main side surface portion (11) and extends perpendicular to the central axis (C) of the cutting insert.

6. the relief surface formed by the first inclined side surface (31) in the first working position is configured to serve as a secondary relief surface for the first main cutting edge (21); a first primary relief surface (41) is formed on the first main side surface portion (11), and the first primary relief surface (41) is adjacent to the first main cutting edge (21) and is located between the first main cutting edge (21) and the first inclined side surface (31), thereby serving as a primary relief surface for the first main cutting edge (21) in the first working position; 6. The double-sided cutting insert according to claim 1, wherein the flank surface formed by the second inclined side surface (32) in the second working position is configured to serve as a secondary flank surface for the second main cutting edge (22), and a second primary flank surface (42) is formed on the first main side surface portion (11), and the second primary flank surface (42) is adjacent to the second main cutting edge (22) and is located between the second main cutting edge (22) and the second inclined side surface (32), thereby serving as a primary flank surface for the second main cutting edge (22) in the second working position.

7. 7. The double-sided cutting insert according to claim 6, characterized in that the first chip deflection surface (51) is adjacent to the first primary relief surface (41) at the first end (50a) of the first chip deflector (50) and the second primary relief surface (42) at the second end (50b) of the first chip deflector (50).

8. The cutting insert (1) has a central plane (MP) extending perpendicular to the central axis (C) of the cutting insert midway between the first main surface (2) and the second main surface (3), each of the first primary flank surface (41) and the second primary flank surface (42) is perpendicular to the central plane (MP) as seen in a section spanning the first primary flank surface (41) and the second primary flank surface (42) that is parallel to a central plane (CP) of the cutting insert that contains the central axis (C) of the cutting insert and a center point (P1) of the first major side portion (11); or 8. The double-sided cutting insert according to claim 6 or 7, characterized in that the first primary flank (41) is inclined outward as viewed in a direction from a first longitudinal edge (41 a) of the first primary flank (41) facing or coinciding with the first main cutting edge (21) towards an opposite second longitudinal edge (41 b) of the first primary flank (41) facing the first inclined flank (31), and the second primary flank (42) is inclined outward as viewed in a direction from a first longitudinal edge (42 a) of the second primary flank (42) facing or coinciding with the second main cutting edge (22) towards an opposite second longitudinal edge (42 b) of the second primary flank (42) facing the second inclined flank (32).

9. the cutting insert (1;1';1'') comprises a through hole (5), the through hole (5) extending centrally through the cutting insert between the first main surface (2) and the second main surface (3), the central axis of the through hole (5) coinciding with the central axis (C) of the cutting insert (1;1';1''); A double-sided cutting insert according to any one of the preceding claims, characterized in that the first chip deflector (50) is arranged in the centre of the first main side surface (11).

10. 10. The double-sided cutting insert according to claim 9, wherein the cutting insert (1; 1'; 1'') has a mid-plane (CP) containing the central axis (C) of the cutting insert and a midpoint (P1) of the first main side surface (11), and the first chip deflecting surface (51) is traversed by the mid-plane (CP) along a line of intersection L extending entirely between the first end (50a) and the second end (50b) of the first chip deflecting member (50).

11. the peripheral surface (10) includes a second major side portion (12) that forms a second peripheral side surface of the cutting insert; a third main cutting edge (23) is formed at the intersection between the second main side portion (12) and the first main surface (2); a fourth main cutting edge (24) is formed at the intersection between the second main side portion (12) and the second main surface (3); A third inclined side surface (33) and a fourth inclined side surface (34) are formed on the second main side surface (12), the third inclined side surface (33) is located between the first main surface (2) and the fourth inclined side surface (34) and is configured to form a clearance surface for the third main cutting edge (23) in a third working position among the working positions, the fourth inclined side surface (34) is located between the second main surface (3) and the third inclined side surface (33) and is configured to form a clearance surface for the fourth main cutting edge (24) in a fourth working position among the working positions, and the third inclined side surface (33) extends from a first edge (33a) of the third inclined side surface (33) facing the first main surface (2) to the fourth inclined side surface (34). the third inclined side surface (33) is inclined inwardly as viewed in a direction toward a second edge (33b) opposite the third inclined side surface (33) facing the inclined side surface (34); the fourth inclined side surface (34) is inclined inwardly as viewed in a direction from a first edge (34a) of the fourth inclined side surface (34) facing the second main surface (3) toward a second edge (34b) opposite the fourth inclined side surface (34) facing the third inclined side surface (33); the third inclined side surface (33) and the fourth inclined side surface (34) are opposite and inclined toward each other, thereby forming a recess (D2) on the second main side surface (12) between the third main cutting edge (23) and the fourth main cutting edge (24); the cutting insert (1) comprises a second chip deflector (60) formed on the second main side surface (12) as a protrusion extending across the depression (D2) formed by the third inclined side surface (33) and the fourth inclined side surface (34), the second chip deflector (60) having a first end (60a) facing the third main cutting edge (23), an opposite second end (60b) facing the fourth main cutting edge (24), and at least a first chip deflection surface (61) extending between the first end (60a) and the second end (60b) of the second chip deflector and configured to deflect chips striking the second main side surface (12) away from the depression (D2) formed by the third inclined side surface (33) and the fourth inclined side surface (34); 11. The double-sided cutting insert according to claim 1, wherein each of the third inclined side surface (33) and the fourth inclined side surface (34) includes a first minor surface (33′, 34′) located on a first side surface of the second chip deflector (60) and a second minor surface (33″, 34″) located on a second side surface opposite the second chip deflector (60).

12. 12. The double-sided cutting insert according to claim 11, characterized in that the first main side portion (11) and the second main side portion (12) are located on opposite sides of the central axis (C) of the cutting insert (1).

13. 13. The double-sided cutting insert according to claim 11 or 12, characterized in that each of the inclined side surfaces (31-34) serves as an abutment surface for the cutting insert (1) in at least one working position of the cutting insert and is configured to abut against a corresponding support surface (87) of an insert seat (84) in a tool body (81) of a milling tool when the cutting insert (1) is mounted in the insert seat (84) in this at least one working position.

14. The cutting insert comprises: a first curved corner cutting edge (25a) and a first surface wiping cutting edge (26a) formed at an intersection between the peripheral surface (10) and the first main surface (2), wherein the first main cutting edge (21), the first curved corner cutting edge (25a), and the first surface wiping cutting edge (26a) are sequentially arranged such that the first curved corner cutting edge (25a) is located between the first main cutting edge (21) and the first surface wiping cutting edge (26a); a second curved corner cutting edge (25b) and a second surface wiping cutting edge (26b) formed at an intersection between the peripheral surface (10) and the second main surface (3), wherein the second main cutting edge (22), the second curved corner cutting edge (25b), and the second surface wiping cutting edge (26a) are sequentially arranged such that the second curved corner cutting edge (25b) is located between the second main cutting edge (22) and the second surface wiping cutting edge (26b); a third curved corner cutting edge (25c) and a third surface wiping cutting edge (26c) formed at an intersection between the peripheral surface (10) and the first main surface (2), wherein the third main cutting edge (23), the third curved corner cutting edge (25c), and the third surface wiping cutting edge (26c) are sequentially arranged such that the third curved corner cutting edge (25c) is located between the third main cutting edge (23) and the third surface wiping cutting edge (26c); 14. The double-sided cutting insert according to claim 11, further comprising a fourth curved corner cutting edge (25d) and a fourth surface-wiping cutting edge (26d) formed at an intersection between the peripheral surface (10) and the second main surface (3), wherein the fourth main cutting edge (24), the fourth curved corner cutting edge (25d), and the fourth surface-wiping cutting edge (26d) are sequentially arranged such that the fourth curved corner cutting edge (25d) is located between the fourth main cutting edge (24) and the fourth surface-wiping cutting edge (26d).

15. Double-sided cutting insert according to any one of claims 1 to 14, characterized in that the cutting insert is a square shoulder milling insert (1) or a face milling insert (1').

16. 16. Double-sided cutting insert according to any one of claims 1 to 15, characterized in that the cutting insert (1; 1'; 1'') is rotationally symmetric through 360 degrees / n about the central axis (C) of the cutting insert, where n is an integer having a value of 2 or greater.

17. A milling tool comprising at least one double-sided cutting insert (1; 1'; 1'') according to any one of claims 1 to 16.

Images