Metal Cutting Turning Tools

Abstract

1. A turning tool (1) comprising a connecting portion (3), the connecting portion (3) extending along a connecting axis (A2), the connecting axis (A2) defining a longitudinal axis of the turning tool (1), the turning tool (1) comprising a first cutting element (7) and a second cutting element (8), the first cutting element (7) comprising a first cutting blade (5), the second cutting element (8) comprising a second nose cutting blade (6) separating and connecting a second leading cutting blade (13) and a second trailing cutting blade (15), the first cutting element (7) comprising a first top surface (20), the second cutting element (8) comprising a second top surface (21), the first top surface (20) and the second top surface (21) facing in the same direction or substantially in the same direction.

Description

[Technical Field]

[0001] The present invention is in the field of metal cutting, more particularly in the field of turning. [Background technology]

[0002] The present invention refers to a turning tool according to the preamble of claim 1. In other words, the present invention relates to a turning tool comprising a coupling part, the coupling part extending along a coupling axis, the coupling axis defining a longitudinal axis of the turning tool, the turning tool comprising a first cutting element and a second cutting element, the first cutting element comprising a first cutting blade, the second cutting element comprising a second nose cutting blade separating and connecting the second front cutting blade and the second rear cutting blade, the first cutting element comprising a first top surface, and the second cutting element comprising a second top surface.

[0003] In a further aspect, the present invention relates to a machining method for a CNC lathe.

[0004] In metal cutting, turning is a common operation. CNC lathes are commonly used. Typically, complex shapes are machined from metal workpieces. To obtain complex shapes, it is common to use two or more turning tools, where the turning tools have different geometries or different orientations. For example, one turning tool may be suitable for machining in one direction, and a second turning tool may be suitable for machining in a different direction.

[0005] Conventionally, each turning tool is equipped with one turning insert. After turning using one turning insert, the first turning tool is typically indexed to a second turning tool. For example, a CNC lathe may include a turret, and indexing from one turning tool to the second turning tool is accomplished by rotating the turret through a predetermined angle. Indexing by rotating the turret can take time, depending on the CNC lathe, for example. The time when no cutting is occurring, such as when changing or indexing from one tool to another, can be referred to as downtime.

[0006] EP 1 317 981 A1 discloses a tool carrying a plurality of turning inserts, with which switching between different turning inserts can be achieved quickly by rotation of the turning tool about a connecting shaft.

[0007] The present inventors have discovered that there is a need for further improved turning tools. Summary of the Invention

[0008] It is an object of the present invention to provide a turning tool suitable for machining objects having complex shapes. A further object is to provide a turning tool that can be used with a wide range of CNC lathes. A still further object is to provide a turning tool that can be used for extended machining operations. A still further object is to provide a turning tool that can help reduce downtime.

[0009] At least one of the foregoing objects is achieved by a turning tool as initially defined, wherein the first top surface and the second top surface face in the same direction or substantially in the same direction.

[0010] With such a turning tool, changing or indexing from a first cutting element to a second cutting element can be quickly achieved through movement of the turning tool along the Y-axis of the CNC lathe to which the turning tool can be connected.

[0011] The turning tool is for a CNC lathe, i.e., a computer or computerized numerically controlled lathe, i.e., any CNC machine suitable for turning, such as, for example, a turning lathe, a multitasking machine, a turn-mill machine, or a sliding-head machine. The turning tool is for machining a metal workpiece, such as a metal workpiece with an external surface that is a radially outer surface, where the radially outer surface faces away from an axis of rotation about which the metal workpiece can rotate. The turning tool is for turning said radially outer surface, i.e., external turning.

[0012] The turning tool includes a forward end and an opposite rearward end in the form of a linkage that is removably connectable to a CNC lathe, and more specifically to a machine interface of the CNC lathe, such as a machine spindle or tool revolver turret or tool post.

[0013] The connector may have a cross section in the shape of a square or rectangle. The connector may be conical or substantially conical, preferably according to ISO standard 26623-1 or the like.

[0014] The coupling portion extends along a coupling axis or central axis, which defines the longitudinal axis of the turning tool.

[0015] The turning tool (1) comprises a first cutting element (7) and a second cutting element (8). The first and second cutting elements are spaced apart. The first and second cutting elements are preferably cutting or turning inserts, i.e., replaceable elements made from a wear-resistant material, such as cemented carbide. Alternatively, the first and second cutting elements may be part of a single wear-resistant element, preferably made from a single piece of cemented carbide. The first cutting element comprises a first top surface. The first top surface comprises a rake face or rake surface.

[0016] The first cutting element comprises a first cutting blade. The first cutting blade comprises at least a portion that is convex in top view. The nose cutting blade, or a portion of the nose cutting blade, generates a machined surface. The first cutting element may be in the form of a circular cutting insert, i.e., an insert that is circular or substantially circular in top view. The radius of said circle is preferably 5 to 30 mm. Alternatively, the first cutting blade may be in the form of a first nose cutting blade that is convex in top view, preferably in the form of a circular arc having a radius of curvature of 0.2 to 1.6 mm and disposed between or connecting the first leading, i.e., primary, or main cutting blade, and the first trailing, i.e., auxiliary, or trailing cutting blade.

[0017] The first top surface may have a diamond, triangle, square, circle, or polygon shape in top view.

[0018] The first and second top surfaces may each be flat. Alternatively, one or both of said surfaces may be non-flat or non-planar. Preferably, said surfaces may comprise one or more chip breaking means in the form of one or more protrusions and / or depressions.

[0019] The direction in which the first top surface faces is the normal of the first top surface, i.e., the direction perpendicular to the first top surface. The direction is away from the first top surface, and, if the first cutting element is in the form of a cutting insert or turning insert having a first bottom surface, is away from the first bottom surface.

[0020] If the first top surface is non-planar, for purposes of defining the direction the first top surface faces, such first top surface may be defined as a plane parallel to or approximately a first mid-plane, said plane intersecting the first nose cutting edge or at least a portion of the first nose cutting edge. When the first cutting element is in the form of a cutting or turning insert having a first bottom surface, said first mid-plane is a plane midway between the first top surface and the first bottom surface.

[0021] Alternatively, the aforementioned first top surface may be defined as a plane that intersects all nose cutting edges that are bounded by or adjacent to the first top surface for purposes of defining the direction in which the first top surface faces.

[0022] Corresponding reasoning applies to the second top surface and the second cutting element.

[0023] The second cutting element includes a second nose cutting edge that separates and connects the second leading cutting edge and the second trailing cutting edge. The second cutting element includes a first top surface. The second top surface includes a rake face or rake surface. The second leading cutting edge is a leading cutting edge. The second trailing cutting edge is a trailing cutting edge.

[0024] The first cutting element is preferably in the form of a first cutting insert having a first top surface and an opposite first bottom surface, the first top surface comprising a first rake face. The second cutting element is preferably in the form of a second cutting insert having a second top surface and an opposite second bottom surface, the second top surface comprising a second rake face. The first bottom surface faces the second top surface.

[0025] The first rake face is associated with the first nose cutting edge and the second rake face is associated with the second cutting edge. The first and second bottom surfaces lie in parallel or substantially planar surfaces.

[0026] The first and second top surfaces face in the same or substantially the same direction, preferably in a direction perpendicular or substantially perpendicular to the link axis, or in a direction perpendicular or substantially perpendicular to a line parallel to the link axis.

[0027] In a top view with the first and second rake faces facing the viewer, the distance from the connecting shaft to the first nose cutting edge is preferably less than the distance from the connecting shaft to the second nose cutting edge.

[0028] The turning tool is preferably suitable for external turning of a cylindrical metal workpiece, such as longitudinal turning. The first and second cutting elements may alternatively be used for longitudinal turning of a metal workpiece that rotates in one direction about its axis of rotation.

[0029] According to one embodiment, the first cutting element comprises a first leading cutting edge and a first trailing cutting edge, the first cutting edge being in the form of a first nose cutting edge, the first nose cutting edge separating and connecting the first leading cutting edge and the first trailing cutting edge.

[0030] Such turning tools allow for machining of more complex shapes, such as grooves. In top view, the first and second forward cutting edges preferably form an angle of 90-174° relative to each other. More preferably, the angle is 95-140°.

[0031] In a top view, the first and second leading cutting blades are preferably angled or tilted in opposite directions relative to the connecting axis. Stated differently, in a top view, one of the first and second leading cutting blades is angled at a positive angle relative to a line parallel to the connecting axis extending midway between the first and second nose cutting blades, and the other is angled at a negative angle relative to that line. More specifically, in a top view, and relative to a line parallel to the connecting axis extending midway between the first and second nose cutting blades, the first leading cutting blade forms a first leading angle preferably between 3 and 45 degrees, and the second leading cutting blade forms a second leading angle preferably between -3 and -45 degrees. The first and second cutting elements are oriented such that, in a top view, i.e., with the first and second cutting faces toward the viewer, the first forward cutting edge and the second forward cutting edge diverge in a forward direction and converge in a rearward direction, where the forward and rearward directions are defined by the connecting axis and the connecting portion defines the rearward direction.

[0032] In a top view, a line coincident with the first leading cutting blade intersects with a line coincident with the second leading cutting blade at an intersection or apex, where the distance from the connector along the connector axis to the first nose cutting blade, measured along a line parallel to the connector axis, is greater than the distance from the connector to said intersection or apex. In other words, said intersection or apex is located rearward compared to the first nose cutting blade.

[0033] Preferably, the first cutting element is arranged such that the first leading cutting edge forms a first cutting angle of 3 to 45° when turning in a first direction perpendicular to the connecting axis, and the second cutting element is arranged such that the second leading cutting edge forms a second cutting angle of 3 to 45° when turning in a second direction opposite to the first direction (and preferably perpendicular to the connecting axis).

[0034] Thus, the first leading cutting edge is arranged to operate or suitable to operate at an acute cutting angle when turning in a first direction perpendicular to the connecting axis, and the second leading cutting edge is arranged to operate at an acute cutting angle when turning in a second direction, said second direction being opposite to said first direction.

[0035] According to one embodiment, in a top view, a first bisector between the first forward cutting blade and the first rearward cutting blade forms an angle of 45 to 90 degrees with respect to a second bisector between the second forward cutting blade and the second rearward cutting blade.

[0036] With such a turning tool, more complex shapes can be machined by the turning tool.

[0037] The top view is one in which the first, top surface faces the viewer.

[0038] According to one embodiment, in a top view, the first and second trailing cutting edges form an angle of 6 to 20 degrees relative to one another.

[0039] With such turning tools, more complex shapes can be machined. With such turning tools, more feed directions are possible.

[0040] More precisely, a line coinciding with the first rear cutting edge in top view forms an angle of 6 to 20° with respect to a line coinciding with the second rear cutting edge in top view.

[0041] According to one embodiment, the distance from the first leading cutting edge to the second leading cutting edge is less than the distance from the first leading cutting edge to the second trailing cutting edge.

[0042] With such turning tools, more complex shapes can be machined. With such turning tools, a first cutting element can be used in one feed direction and a second cutting element can be used in the opposite feed direction.

[0043] The aforementioned distances are measured along a line perpendicular to the link axis in a top view.

[0044] According to one embodiment, the first nose angle, defined as the angle between the first leading cutting edge and the first trailing cutting edge, is an acute angle.

[0045] Such turning tools allow machining of more complex shapes. The aforementioned nose angle is preferably 25 to 80°, more preferably 30 to 60°. The first nose angle is found on the top surface.

[0046] According to one embodiment, the second nose angle, defined as the angle between the second leading cutting edge and the second trailing cutting edge, is an acute angle.

[0047] Such a turning tool allows machining of more complex shapes. The second nose angle is preferably 25 to 80°, and more preferably 30 to 60°. The second nose angle is measured in a top view.

[0048] According to one embodiment, the first and second nose cutting edges are located at equal or substantially equal longitudinal distances.

[0049] Such a turning tool requires less movement when indexing from the first cutting element to the second cutting element. This is measured longitudinally from the connector along a line parallel to the connector axis. Substantially equal distances mean within 5 mm, preferably within 2 mm. When the aforementioned distances are substantially equal rather than equal, i.e., within 5 mm, the first nose cutting edge is preferably further from the connector.

[0050] According to one embodiment, the first nose cutting edge and / or the second nose cutting edge is the longitudinally most distal portion of the turning tool.

[0051] In other words, the first and / or second nose cutting edge are the longitudinally most forward portions of the turning tool, where the connecting axis is the longitudinal axis and the connecting portion defines the rearward or trailing end.

[0052] According to one embodiment, the first cutting element is in the form of a first turning insert and the second cutting element is in the form of a second turning insert, the first turning insert comprising a first nose cutting edge and the second turning insert comprising a second nose cutting edge, a second leading cutting edge, and a second trailing cutting edge.

[0053] The first turning insert preferably includes a first leading cutting edge and a first trailing cutting edge.

[0054] According to one embodiment, the first turning insert comprises a first top surface and an opposite first bottom surface, with a first mid-plane extending substantially midway between the first top surface and the first bottom surface, and the second turning insert comprises a second top surface and an opposite second bottom surface, with the second mid-plane extending substantially midway between the second top surface and the second bottom surface, with the first mid-plane and the second mid-plane extending in parallel or substantially parallel planes.

[0055] According to one embodiment, in a top view, the first turning insert and the second turning insert partially overlap.

[0056] The first turning insert and the second turning insert partially but not completely overlap.

[0057] According to one embodiment, the turning tool comprises a third cutting element.

[0058] The third cutting element is preferably in the form of a third cutting insert. The shape of the third turning insert is preferably different in top view from the shapes of the first and second turning inserts.

[0059] In top view, the first, second, and third cutting elements preferably partially overlap.

[0060] The turning tool preferably comprises a third protrusion, in which case the third protrusion comprises a third cutting element.

[0061] According to one embodiment, the link is square or rectangular in cross section or comprises a conical or substantially conical portion.

[0062] The aforementioned cross-sections are in a plane perpendicular to the connection axis. The connection preferably comprises a conical or substantially conical portion and a ring-shaped portion, such as a polygonal hollow tapered joining portion with a flange contact surface according to ISO 26623-1:2014 or a hollow tapered joining portion with a flange contact surface according to DIN 69893, ISO 12164-1 or ISO 12164-1F.

[0063] According to one embodiment, a turning method for a CNC lathe includes the steps of providing a metal workpiece, providing a turning tool according to any of the above embodiments, rotating the metal workpiece in one direction about its axis of rotation, turning in the first direction so that a first nose cutting blade is cutting, moving the turning tool in one direction so that the first nose cutting blade is moved away from the metal workpiece and the second nose cutting blade is moved towards the metal workpiece, and moving the turning tool in a second direction so that the second leading cutting blade operates at a second cutting angle of 5 to 45 degrees, the second direction being opposite or substantially opposite to the first direction.

[0064] The turning method is for a CNC lathe, i.e., a computer or computerized numerically controlled lathe, i.e., any CNC machine suitable for turning, such as, for example, a turning lathe, a multitasking machine, a turn-mill machine, or a sliding-head machine. A metal workpiece is provided. The metal workpiece has an outer surface, which is a radially outer surface. The radially outer surface faces away from the axis of rotation. The turning method is for turning the radially outer surface, i.e., external turning. The metal workpiece extends between a first end and a second end. The metal workpiece is clamped by a clamping means. The clamping means holds the metal workpiece and is at least partially controlled and driven by a motor or spindle.

[0065] The clamping means may be in the form of a collet chuck, face driver, or three-jaw chuck, and may also include a tailstock. The headstock end of the machine is preferably positioned at the first end of the metal workpiece. The second end of the metal workpiece opposite the first end of the workpiece may be the free end. Alternatively, the second end is in contact with the tailstock.

[0066] The method includes rotating the metal workpiece about its axis of rotation in one direction, which may be clockwise or counterclockwise.

[0067] Preferably, the method includes the step of setting the connecting shaft perpendicular to the axis of rotation.

[0068] The method includes turning in a first direction. The first direction may preferably be parallel to the axis of rotation, also known as longitudinal turning. The aforementioned steps are included in a first pass, defined as between beginning the cut and ending the cut. The first pass is not necessarily a movement of the first cutting element along a straight line. When turning in the first direction, a first nose cutting edge is in operation. A cutting finish surface is formed by the first nose cutting edge.

[0069] The first cutting element preferably comprises a first leading cutting edge and a first trailing cutting edge, wherein a first nose cutting edge separates and connects the first leading cutting edge and the first trailing cutting edge, and wherein the first leading cutting edge forms an acute first cutting angle when turning in the first direction.

[0070] After or during the completion of the cut, the turning tool is moved such that the first nose cutting edge is moved away from the metal workpiece and the second nose cutting edge is moved toward the metal workpiece, and during at least a portion of said movement, neither the first nor the second cutting element is operating, i.e., no metal is cut by the first or second cutting elements during said movement.

[0071] The aforementioned movement of the turning tool may preferably be a linear movement, i.e. the turning tool is moved in a straight line.

[0072] Preferably, the movement of the turning tool is in a direction perpendicular to the articulation axis and perpendicular to the rotation axis, and preferably in a direction perpendicular or substantially perpendicular to the first top surface.

[0073] The method includes turning in a second direction, i.e., moving the turning tool in a second direction. The second direction is opposite or substantially opposite to the first direction. For example, the first and second directions may be parallel to the axis of rotation but opposite directions. The aforementioned steps are included in a second pass, defined as between starting and finishing the cut. The second pass is not necessarily a straight line of movement of the first cutting element. A finished cutting surface is formed by the second nose cutting edge. The second nose cutting edge and the second leading cutting edge are operated such that the second leading cutting edge operates at a second cutting angle of 5 to 45°, more preferably 5 to 30°.

[0074] The second cutting element is inactive when turning in the first direction, and the first cutting element is inactive when turning in the second direction.

[0075] Preferably, the method includes the further step of setting the second trailing cutting edge to form an obtuse clearance angle when turning in the second direction, said clearance angle preferably being between 91° and 135°, more preferably between 93° and 120°.

[0076] Preferably, the method includes the further step of setting the first trailing cutting edge to form a front clearance angle of at least 91° when turning in the first direction.

[0077] Preferably, the method includes the further step of turning at least a portion of the surface machined in the first pass while turning in the second direction.

[0078] The step of moving the turning tool so that the first nose cutting edge is moved away from the metal workpiece and the second nose cutting edge is moved toward the metal workpiece preferably does not involve rotation of the turning tool about the connecting center axis. The aforementioned step is preferably a linear movement of the turning tool, preferably along the Y axis of the CNC lathe. Thereby, indexing time can be reduced compared to rotational movement.

[0079] The turning tool preferably does not rotate about the connecting axis during the first pass, during the second pass, or between the first and second passes. The turning tool preferably does not rotate about any other axis, such as any axis parallel to the connecting axis, during the first and second passes, or between the first and second passes.

[0080] The method preferably includes the step of positioning first and second nose cutting edges spaced apart a fixed distance along the axis of rotation while turning in the first and second directions, and preferably also during a step between the first and second passes.

[0081] Preferably, the method includes setting the connecting shaft perpendicular to the axis of rotation.

[0082] The method preferably includes the step of clamping the metal workpiece with clamping means, in which case the clamping means comprises a three-jaw chuck.

[0083] The distance from the clamping means to the second nose cutting blade is preferably shorter than the distance from the clamping means to the first nose cutting blade.

[0084] The second nose cutting edge is preferably located forward of the first nose cutting edge when turning in the first direction.

[0085] Preferably, the first nose cutting edge is located ahead of the second nose cutting edge when turning in the second direction, where ahead should be understood as ahead in the feed direction along the axis of rotation.

[0086] The second pass is preferably in a direction away from the corner. The corner or shoulder is defined as the intersection between a first surface concentric with the axis of rotation and a second surface perpendicular to the axis of rotation. The first surface may be the exterior surface or the interior surface, i.e., the surface inside the lumen. Preferably, the first surface is the exterior surface, i.e., the radially outer surface.

[0087] According to one aspect of the present invention, there is provided a computer program having instructions which, when executed by a CNC lathe, cause the CNC lathe to perform steps according to any of the methods described above.

[0088] The computer program or computer program product may be included in a CAM software product, i.e., software for computer-aided manufacturing. The computer program may be in the form of a computer-readable medium, such as a USB stick, a CD-ROM, or a data stream.

[0089] The invention will now be explained in more detail by a description of embodiments of the invention and by reference to the accompanying drawings. [Brief explanation of the drawings]

[0090] [Figure 1] FIG. 1 is a perspective view of a turning tool according to one embodiment. [Figure 2] FIG. 2 is a side view of the turning tool in FIG. [Figure 3] FIG. 2 is a front view of the turning tool in FIG. [Figure 4] FIG. 2 is a top view of the turning tool in FIG. [Figure 5] FIG. 5 is an enlarged view of section B in FIG. [Figure 6] FIG. 2 is a top view of the turning tool and metal workpiece in FIG. 1. [Figure 7] FIG. 2 is a side view of the turning tool and metal workpiece in FIG. 1. [Figure 8] FIG. 2 is a top view of the turning tool and metal workpiece in FIG. 1. [Figure 9] FIG. 1 is a schematic diagram of moving a turning tool in a first direction. [Figure 10] FIG. 10 is a schematic diagram of moving the turning tool in a second direction. [Figure 11] 1 is a schematic diagram showing a first cutting element and a rotating metal workpiece in cross section. DETAILED DESCRIPTION OF THE INVENTION

[0091] All turning tools in the figures are drawn to scale.

[0092] 1-8, which illustrate a turning tool 1 according to one embodiment. The turning tool 1 comprises a coupling portion 3. The coupling portion 3 extends along a coupling axis A2. The coupling axis A2 defines a longitudinal axis of the turning tool 1. The coupling portion 3 comprises a conical or substantially conical portion. In an example, the substantially conical portion is in accordance with what is known in the industry as Coromant Capto®. The coupling portion may have other shapes, such as a square or rectangular shape in cross section, said cross section being perpendicular to the coupling axis.

[0093] The turning tool 1 includes a first cutting element 7 in the form of a first turning insert 7, a second cutting element 8 in the form of a second turning insert 8, and a third cutting element 9 in the form of a third turning insert 9. The first turning insert 7 includes a first cutting edge 5 in the form of a first nose cutting edge 5, a first leading cutting edge 12, and a first trailing cutting edge 14. The first nose cutting edge 5 separates and connects the first leading cutting edge 12 and the first trailing cutting edge 14. The first turning insert 7 includes a first top surface 20 and an opposite first bottom surface. The second turning insert 8 includes a second nose cutting edge 6, a second leading cutting edge 13, and a second trailing cutting edge 15. The second nose cutting edge 6 separates and connects the second leading cutting edge 13 and the second trailing cutting edge 15. In other words, the second leading cutting edge 13 and the second trailing cutting edge 15 converge toward the second nose cutting edge 6. The second cutting element 8 includes a second top surface 21 and an opposite second bottom surface.

[0094] A first mid-plane P1 extends midway or substantially midway between the first top surface 20 and the first bottom surface. The first mid-plane P1 is parallel or substantially parallel to the first bottom surface. Correspondingly, the second turning insert 8 has a second top surface 21 and an opposite second bottom surface, and a second mid-plane P2 extends midway or substantially midway between the second top surface 21 and the second bottom surface. The third turning insert 9 is correspondingly disposed with a third mid-plane P3 midway between its top and bottom surfaces. The aforementioned top surfaces 20, 21 are suitable for functioning as rake surfaces. The first, second, and third mid-planes P1, P2, P3 extend in parallel or substantially parallel planes. For example, as can be seen in FIG. 2, first top surface 20 and second top surface 21 face in the same or substantially the same direction, which is upward in FIG.

[0095] As can be seen in FIG. 3, the distance from the connecting axis A2 to the second nose cutting blade is greater than the distance from the connecting axis A2 to the first nose cutting blade 5. The aforementioned distances are measured horizontally in FIG. 3. In other words, the aforementioned distances from a first plane containing the connecting axis, the aforementioned first plane being perpendicular to the first central plane. Therefore, the aforementioned distances are from the aforementioned first plane to the first nose cutting blade 5 and the second nose cutting blade 6. As can be seen in FIG. 4 and FIG. 5, which is an enlarged view of section B in FIG. 4, in a top view, the first bisector between the first leading cutting blade 12 and the first trailing cutting blade 14 forms an angle of 45 to 90° with respect to the second bisector between the second leading cutting blade 13 and the second trailing cutting blade 15. It can also be seen that the first trailing cutting blade 14 and the second trailing cutting blade 15 form an angle of 6 to 20° with respect to each other. Furthermore, the distance from the first leading cutting edge 12 to the second leading cutting edge 13 is shorter than the distance from the first leading cutting edge 12 to the second trailing cutting edge 15. The first nose angle, defined as the angle between the first leading cutting edge 12 and the first trailing cutting edge 14, is an acute angle. The second nose angle, defined as the angle between the second leading cutting edge 13 and the second trailing cutting edge 15, is an acute angle. For example, in FIG. 4 , the first nose cutting edge 5 and the second nose cutting edge 6 are located at equal or substantially equal distances in the longitudinal direction. The first nose cutting edge 5 and / or the second nose cutting edge 6 are the longitudinally most distal portions of the turning tool 1, where longitudinally is defined as along the articulation axis or along a line parallel to the articulation axis A2.

[0096] In FIG. 5, the first turning insert 7 and the second turning insert 8 partially overlap in top view.

[0097] FIG. 6 shows an example of a first step of a turning method for a CNC lathe (not shown). A metal workpiece 2 rotates in one direction 50 around its rotation axis A1. The coupling 3 of the turning tool 1 is connected to the CNC lathe (not shown), and more specifically, the coupling is connected to a machine interface. The coupling axis A2 is perpendicular to the rotation axis A1. The turning tool 1 is moved in a first direction 17 so that the first nose cutting edge 5 cuts and the first leading cutting edge forms an acute leading edge angle. The first trailing cutting edge 14 forms an obtuse leading edge angle. The second and third turning inserts 8, 9 are spaced apart from the metal workpiece 2. The second nose cutting edge is located forward of the first nose cutting edge 5 in the first direction 17. The first direction is parallel to the rotation axis A1.

[0098] After the first step, the turning tool 1 is moved in a direction 19 that is perpendicular to the connection axis A2 and perpendicular to the rotation axis A1, as seen in FIG. 7 . Said direction 19 is the same direction as or substantially the same as the direction in which the first top surface 20 faces. Said direction 19 is along the Y-axis of a CNC lathe (not shown) to which the turning tool 1 is connected. Said direction 19 is not radial with respect to the rotation axis A1, but rather is tangential with respect to the metal workpiece 2. The said movement of the turning tool 1 is a linear movement such that the first nose cutting edge is moved further away from the metal workpiece 2 and the second nose cutting edge 6 is moved closer to or toward the metal workpiece 2. None of the first, second, or third cutting inserts 7, 8, 9 is cutting.

[0099] FIG. 8 shows a further step following the step shown in FIG. 7. The turning tool 1 is moved in a second direction 18 such that the second leading cutting edge 13 cuts at an acute second leading angle β of 5 to 45°. A cutting surface is formed by the second nose cutting edge 6. The second direction 18 is opposite or substantially opposite to the first direction 17. The second trailing cutting edge 15 forms an obtuse leading clearance angle. The first nose cutting edge is located forward of the second nose cutting edge 6 in the second direction. The first and third turning inserts 7, 9 are spaced apart from the metal workpiece 2. At least a portion of the cutting surface resulting from the step shown in FIG. 6 is machined in the step shown in FIG. 8.

[0100] The metal workpiece may have various shapes compared to those described above. The metal workpiece may be in the form of a rod, a hollow bar, or any other shape that has rotational symmetry or substantially rotational symmetry around its axis of rotation. The shapes that can be machined may be configured differently from those described above. For example, the shape may have two sidewalls, i.e., two surfaces in a plane perpendicular to the axis of rotation, rather than just one sidewall. In other words, the turning tool may be used to machine an external groove.

[0101] FIG. 9 is a schematic diagram of a turning tool moving in a first direction 17, with a first cutting element 7 cutting. The first direction 17 is the feed direction. The first leading cutting edge forms a first entering angle α that is between 5 and 45°, and the first trailing cutting edge forms an obtuse clearance angle γ of at least 91°. A second cutting element 8 is spaced from the metal workpiece 2. A cutting finish surface 25 is formed by the first cutting element 7. More specifically, surface 25 is formed by the first nose cutting edge 5.

[0102] FIG. 10 is a schematic illustration of moving the turning tool in a second direction 18, with the second cutting element 8 cutting. The second direction is the feed direction. The second leading cutting edge is cutting at a second entering angle β that is between 5 and 45°, and the second trailing cutting edge forms an obtuse clearance angle δ. At least a portion of the surface 25 that was machined when moving the turning tool 1 in the first direction 17 seen in FIG. 9 is machined by the second cutting element 8 in FIG. 10.

[0103] Figure 9 shows a first machining step, followed by the steps shown in Figure 10. In Figure 10, the second cutting element 8 is on the same side of the rotation axis A1 as the first cutting element 7 in Figure 9, and the first top surface faces in the same direction as the second top surface.

[0104] 24 and 25, the metal workpiece 2 is clamped at one end by a clamping means 60. The clamping means 60 is connected to and driven by a rotating or rotatable spindle (not shown) that is part of a CNC lathe (not shown). The clamping means may be in the form of a collet chuck, a three-jaw chuck, or a face driver. The distance from the clamping means 60 to the second nose cutting blade 6 is less than the distance from the clamping means 60 to the first cutting blade 5, and the distance is measured along a line parallel to the axis of rotation A1. In FIGS. 24 and 25, the first direction 17 is a direction away from the clamping means 60, and the second direction 18 is a direction toward the clamping means. Alternatively (not shown), the first direction 17 is a direction toward the clamping means 60, and the second direction 18 is a direction away from the clamping means. The first and second directions 17, 18 are therefore opposite directions along the axis of rotation A1, and are therefore understood as being towards or away from the clamping means, or towards or away from one longitudinal end of the metal workpiece 2. The first and second directions 17, 18 are therefore not necessarily straight and parallel to the axis of rotation A1.

[0105] FIG. 11 is a schematic cross-sectional view of a first cutting element 7 in the form of a first turning insert 7 and a rotating metal workpiece 2. The first turning insert 7 has a first top surface 20 and a first bottom surface 22, both of which are horizontal or substantially horizontal. A first mid-plane P1 is located mid-way or substantially mid-way between the first top surface 20 and the first bottom surface 22. The first mid-plane P1 is parallel or substantially parallel to the second bottom surface 22. The metal workpiece 2 rotates in one direction 50 about its rotation axis A1. The first top surface 20 faces upward in the figure. When the first turning insert 7 is cutting, a second turning insert (not shown) is spaced apart from the metal workpiece 2.

[0106] FIG. 10 shows how the second direction 18 is directed away from the corner of the metal workpiece 2. In other words, the second direction 18 is directed away from a surface that is in a plane perpendicular to the rotation axis A1. The corner, or shoulder, is the intersection between a surface concentric with the rotation axis and a second surface that is perpendicular to the rotation axis. The corner is a 90° corner. Preferably, the corner is formed entirely by the second cutting element, in which case the turning tool is moved toward the rotation axis A1 immediately before moving the turning tool in the second direction 18.

[0107] The first and second turning inserts 7, 8 described in the above embodiments are preferably made of a wear-resistant material, preferably a cemented carbide. The first and second top surfaces 20, 21 are preferably provided with chip-forming or chip-breaking means (not shown). The distance from at least a portion of the chip-forming or chip-breaking means to the central plane of the respective turning insert is preferably greater than the distance from the cutting edge bordering the top surface to the central plane. In other words, the top surfaces 20, 21 of the first and second turning inserts are provided with at least one protrusion that is higher than or located above the cutting edge in side view. In this way, the turning inserts are more suitable for turning.

[0108] The first and second turning inserts 7, 8 described in the above embodiments are preferably designed such that the first leading cutting edge 12 slopes downward, i.e., towards the first bottom surface 22, with increasing distance from the first nose cutting edge 5. The second leading cutting edge 13 is preferably arranged in a corresponding manner. In this way, chip control is further improved.

[0109] The leading and trailing cutting edges are forward and trailing in the respective feed direction, and not necessarily forward or trailing relative to the leading or trailing direction of the turning tool itself.

Claims

1. A turning tool (1) comprising a connecting part (3), The connecting portion (3) extends along a connecting axis (A2), The connecting shaft (A2) defines the longitudinal axis of the turning tool (1), The turning tool (1) comprises a first cutting element (7) and a second cutting element (8), said first cutting element (7) comprising a first cutting edge (5); the second cutting element (8) comprises a second nose cutting edge (6) separating and connecting a second leading cutting edge (13) and a second trailing cutting edge (15); the first cutting element (7) comprises a first top surface (20); the second cutting element (8) comprises a second top surface (21); In the turning tool (1), The first top surface (20) and the second top surface (21) face in the same direction and comprise a rake surface; said first cutting element (7) comprising a first forward cutting edge (12) and a first rearward cutting edge (14); said first cutting edge (5) being in the form of a first nose cutting edge (5); the first nose cutting edge (5) separates and connects the first leading cutting edge (12) and the first trailing cutting edge (14); 1. A turning tool (1), characterized in that, in top view, a first bisector between the first front cutting edge (12) and the first rear cutting edge (14) forms an angle of 45 to 90° with a second bisector between the second front cutting edge (13) and the second rear cutting edge (15).

2. In top view, the first rear cutting edge (14) and the second rear cutting edge (15) form an angle of 6 to 20 degrees with respect to each other; A turning tool (1) according to claim 1.

3. The distance from the first front cutting edge (12) to the second front cutting edge (13) is shorter than the distance from the first front cutting edge (12) to the second rear cutting edge (15). A turning tool (1) according to claim 1 or 2.

4. a first nose angle defined as the angle between the first leading cutting edge (12) and the first trailing cutting edge (14) is an acute angle; A turning tool (1) according to any one of claims 1 to 3.

5. a second nose angle defined as the angle between the second leading cutting edge (13) and the second trailing cutting edge (15) is an acute angle; A turning tool (1) according to any one of claims 1 to 4.

6. the first nose cutting edge (5) and the second nose cutting edge (6) are located at equal distances in the longitudinal direction of the turning tool (1); A turning tool (1) according to any one of claims 1 to 5.

7. the first nose cutting edge (5) and / or the second nose cutting edge (6) are the longitudinally most distal portions of the turning tool (1); A turning tool (1) according to any one of claims 1 to 6.

8. said first cutting element (7) being in the form of a first turning insert (7); said second cutting element (8) being in the form of a second turning insert (8); the first turning insert comprises the first nose cutting edge (5); the second turning insert (8) comprises the second nose cutting edge (6), the second front cutting edge (13), and the second rear cutting edge (15); A turning tool (1) according to any one of claims 1 to 7.

9. the first turning insert (7) comprises a first top surface (20) and an opposite first bottom surface (22); a first central plane (P1) extending midway between said first top surface (20) and said first bottom surface (22); the second turning insert (8) comprises a second top surface (21) and an opposite second bottom surface (23); a second central plane (P2) extending midway between the second top surface (21) and the second bottom surface (23); the first mid-plane (P1) and the second mid-plane (P2) extend in parallel planes, A turning tool (1) according to claim 8.

10. In a top view, the first turning insert (7) and the second turning insert (8) partially overlap. Turning tool (1) according to claim 8 or 9.

11. a third cutting element (9); A turning tool (1) according to any one of claims 1 to 10.

12. the connecting part (3) has a square or rectangular cross section or comprises a conical part, A turning tool (1) according to any one of claims 1 to 11.

13. 1. A turning method for a CNC lathe, comprising: providing a metal workpiece (2); Providing a turning tool (1) according to any one of claims 1 to 12; Rotating the metal workpiece (2) in one direction (50) around its rotation axis (A1); turning in a first direction (17) so that the first nose cutting edge (5) cuts; moving the turning tool (1) in a direction (19) such that the first nose cutting edge (5) is moved away from the metal workpiece (2) and the second nose cutting edge (6) is moved towards the metal workpiece (2); moving the turning tool (1) in a second direction (18) so that the second leading cutting edge (13) operates at a second cutting angle (β) of 5 to 45°; moving the turning tool (1) in a second direction (18), the second direction (18) being opposite to the first direction (17); A turning method comprising:

14. 14. A computer program having instructions that, when executed by a CNC lathe, cause the CNC lathe to perform the steps of claim 13.

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