Turning tools for metal cutting

Abstract

A turning tool (1) includes a connecting portion (3) extending along a connecting axis (A2) that defines a longitudinal axis of the turning tool (1). The turning tool (1) includes a first cutting element (7) and a second cutting element (8). The first cutting element (7) includes a first cutting edge (5). The second cutting element (8) includes a second tip cutting edge (6) that separates and connects a second forward cutting edge (13) and a second backward cutting edge (15). The first cutting element (7) includes... A first top surface (20), wherein the second cutting element (8) includes a second top surface (21), wherein the first cutting element (7) and the second cutting element (8) intersect an imaginary circle or cylinder (C1) whose central axis (A3) is parallel to or coincides with the connecting axis (A2), wherein the first cutting element (7) is inclined relative to the second cutting element (8) at an angle (ω), wherein the angle (ω) is measured about the central axis (A3) of the imaginary circle (C1), wherein the first top surface (20) faces a direction perpendicular to or substantially perpendicular to the connecting axis (A2).

Description

Technical Field

[0001] This invention belongs to the technical field of metal cutting. More specifically, this invention belongs to the field of turning. Background Technology

[0002] This invention relates to a turning tool according to the present invention. In other words, the invention relates to a turning tool including a connecting portion, wherein the connecting portion extends along a connecting axis that defines the longitudinal axis of the turning tool, wherein the turning tool includes a first cutting element and a second cutting element, wherein the first cutting element includes a first cutting edge, and wherein the second cutting element includes a second tip cutting edge that separates and connects a second forward cutting edge and a second backward cutting edge, wherein the first cutting element includes a first top surface, and wherein the second cutting element includes a second top surface. In another aspect, the invention relates to a machining method for a CNC lathe.

[0003] Turning is a common operation in metal cutting. CNC lathes are commonly used. Typically, complex shapes are machined from metal workpieces. To achieve complex shapes, two or more turning tools are usually used, with different geometries or orientations. For example, one turning tool may be suitable for machining in one direction, while a second turning tool may be suitable for machining in a different direction.

[0004] Typically, each turning tool is equipped with one cutting insert. After turning with one cutting insert, the first turning tool is usually indexed to a second turning tool. For example, a CNC lathe may include a turret, and indexing from one turning tool to another is achieved by rotating the turret by a predetermined angle. Indexing via turret rotation takes time, which depends on the CNC lathe, for example. The time without cutting, such as when changing or indexing from one tool to another, can be called downtime.

[0005] EP 1 317 981 A1 discloses a tool carrying multiple turning inserts, thereby enabling rapid switching between different turning inserts by rotating the turning tool around a connecting axis.

[0006] The inventors have discovered the need for a further improved turning tool. Summary of the Invention

[0007] One object of the present invention is to provide a turning tool suitable for machining objects with complex shapes. A further object is to provide a turning tool that can be used on a wide range of CNC lathes. A further object is to provide a turning tool that can be used for long-term machining operations. Another object is to provide a turning tool that can help reduce downtime.

[0008] At least one of the objectives is achieved by a initially defined turning tool, wherein the first and second cutting elements intersect an imaginary circle or cylinder whose central axis is parallel to or coincides with the connecting axis, wherein the first cutting element is inclined at an angle relative to the second cutting element, wherein the angle is measured about the central axis of the imaginary circle, and wherein the first top surface faces a direction perpendicular to or substantially perpendicular to the connecting axis.

[0009] With this type of turning tool, a very rapid change or indexing from the first cutting element to the second element can be achieved through the linear motion of the turning tool.

[0010] Turning tools are used on CNC lathes, i.e., computerized or computerized numerical control lathes, that is, any CNC machine tool suitable for turning, such as turning lathes, multi-tasking lathes, milling lathes, or sliding head lathes. Turning tools are used to machine metal workpieces, such as metal workpieces including an outer surface, which is a radial outer surface, wherein the radial outer surface faces away from the axis of rotation about which the metal workpiece can rotate. Turning tools are used to turn said radial outer surface, i.e., external turning.

[0011] Turning tools consist of a front end and an opposite rear end in the form of a connecting part. The connecting part can be detachably connected to a CNC lathe, and more specifically, to a machine tool interface of the CNC lathe, such as a machine spindle or tool turret or tool post.

[0012] The cross-section of the connecting part can be square or rectangular. The connecting part can be tapered or substantially tapered, such as preferably in the shape according to ISO standard 26623-1.

[0013] The connecting portion extends along the connecting axis or central axis, which defines the longitudinal axis of the turning tool.

[0014] A turning tool includes a first cutting element and a second cutting element. The first and second cutting elements are spaced apart. The first and second cutting elements are preferably cutting inserts or turning inserts, i.e., replaceable elements made of a wear-resistant material (e.g., cemented carbide). Alternatively, the first and second cutting elements may be portions of a single wear-resistant element, which is preferably made of a single piece of cemented carbide. The first cutting element includes a first top surface. The first top surface includes a rake face or a front face.

[0015] The first cutting element includes a first cutting edge. The first cutting edge may preferably be in the form of a tool-tip cutting edge, i.e., a convex cutting edge in a top view. The first cutting edge or a portion of the first cutting edge creates a machined surface. The first cutting element may be in the form of a rounded cutting insert, i.e., an insert that is circular or substantially circular in a top view. The radius of the circle is preferably 5-30 mm. Alternatively, the first cutting edge may be a tool-tip cutting edge that is convex in a top view, preferably in the form of an arc with a radius of curvature of 0.2-1.6 mm, and is arranged between a first forward cutting edge (i.e., the main cutting edge or primary cutting edge or front cutting edge) and a first backward cutting edge (i.e., the auxiliary cutting edge or tail cutting edge), i.e., connecting the first forward cutting edge and the first backward cutting edge.

[0016] Alternatively, the first top surface may have a rhomboid, triangular, square, or polygonal shape in the top view.

[0017] Both the first and second top surfaces can be flat. Alternatively, one or both surfaces can be uneven or non-planar. Preferably, the surfaces can include one or more chip-breaking devices in the form of one or more protrusions and / or recesses.

[0018] The direction facing the first top surface is the normal to the first top surface, i.e., the direction perpendicular to the first top surface. If the first cutting element is in the form of a cutting insert or turning insert with a first bottom surface, then the direction is away from the first top surface and away from the first bottom surface.

[0019] In cases where the first top surface is not flat, to determine the direction in which the first top surface faces, such a first top surface can be defined as or approximately as a plane parallel to the first intermediate plane, wherein the plane intersects the first cutting edge or at least a portion of the first cutting edge. If the first cutting element is in the form of a cutting insert or turning insert having a first bottom surface, then the first intermediate plane is the plane intermediate between the first top surface and the first bottom surface.

[0020] Alternatively, in order to determine the orientation of the first top surface, the first top surface may be defined as a plane that intersects with all cutting edges of the tool tip that are adjacent to or border the first top surface.

[0021] The corresponding reasoning applies to the second top surface and the second cutting element.

[0022] The second cutting element includes a second tip cutting edge that separates and connects a second forward cutting edge and a second backward cutting edge. The second cutting element includes a first top surface. The second top surface includes a rake face or a front face. The second forward cutting edge is a front cutting edge. The second backward cutting edge is a tail cutting edge.

[0023] This turning tool is suitable for external turning of cylindrical metal workpieces, such as preferably longitudinal turning. The first and second cutting elements can be used alternately for longitudinal turning of a metal workpiece rotating in one direction about its axis of rotation.

[0024] The first and second cutting elements intersect or are arranged along an imaginary circle or cylinder, the central axis of which is parallel to or coincides with the connecting axis. Preferably, the central axis coincides with or substantially coincides with the connecting axis. Substantially coincident means a distance of less than 20 mm from the connecting axis. The first cutting element is inclined relative to the second cutting element at an angle. Preferably, the angle is at least 45°. More preferably, the angle is 180° + / - 20°, and even more preferably 180° + / - 10°. If the angle is 180°, the central axis of the imaginary circle or cylinder lies between the first cutting edge and the second cutting tip.

[0025] A turning tool is arranged for turning a metal workpiece capable of rotating about its axis of rotation, which is parallel to the central axis. The second cutting edge is the portion of the second cutting element closest to the central axis. The first cutting edge is the portion of the first cutting element closest to the central axis.

[0026] The angle at which the first top surface is inclined relative to the second top surface is equal to the tilt angle or within + / - 20° of the tilt angle. This angle is equal to the tilt angle if both the first and second top surfaces extend radially from the central axis of an imaginary circle. Alternatively, the first and / or second cutting elements can be tilted positively or negatively by up to 10°. In another alternative, the first and / or second top surfaces can be arranged to form a positive or negative rake angle.

[0027] The first and second top surfaces are aligned in the same direction along the hypothetical circle; in other words, the first and second top surfaces either both face clockwise or both face counterclockwise.

[0028] The first top surface is oriented in a direction that is perpendicular or substantially perpendicular to the connecting axis or within 15°. In other words, the first presenting direction of the primary motion of the first cutting element according to ISO 3002-1:1982 is in a direction that is perpendicular or substantially perpendicular (i.e., within 15°) to an axis parallel to the connecting axis.

[0029] The first tool reference plane according to ISO 3002-1:1982 associated with the first cutting element and the second tool reference plane according to ISO 3002-1:1982 associated with the second cutting element may be parallel or coincident. Coincidence means that the first and second tool reference planes lie in a common plane. The connecting axis preferably extends in said common plane. Alternatively, the connecting axis extends in a plane parallel to said common plane. Alternatively, if the tool reference planes do not extend in a common plane, the first and second tool reference planes may form an angle relative to each other, wherein the angle is equal to the angle between the first presenting direction of the primary movement of the first cutting element and the second presenting direction of the primary movement of the second cutting element. Preferably, the first and second tool reference planes intersect along a line that coincides with or is parallel to the axis of rotation of the metal workpiece to be machined.

[0030] When viewed in a front view, the directions facing the first top surface and the second top surface can differ by 180° or approximately 180°. In this case, the first orientation of the primary motion of the first cutting element according to ISO 3002-1:1982 is in the opposite direction to the second orientation of the primary motion of the second cutting element. Preferably, the direction facing the first top surface differs from the direction facing the second top surface by at least 40°.

[0031] No part of the turning tool is between the first cutting edge and the second cutting edge.

[0032] The turning tool includes a middle section, which is located longitudinally between the connecting section and the cutting element.

[0033] The first and second cutting elements are preferably longitudinally overlapped, wherein the longitudinal direction is defined by the connecting axis.

[0034] The first and second cutting edges are free ends. In other words, the cutting edges are positioned to allow for metal cutting operations.

[0035] According to one embodiment, the first cutting element includes a first forward cutting edge and a first backward cutting edge, wherein the first cutting edge is a first tip cutting edge; wherein the first tip cutting edge separates the first forward cutting edge and the first backward cutting edge and connects the first forward cutting edge and the first backward cutting edge.

[0036] With such a turning tool, more complex shapes can be machined. For example, grooves can be machined. The first forward cutting edge (main cutting edge or primary cutting edge) and the first backward cutting edge (auxiliary cutting edge) are preferably straight or linear, or substantially straight or substantially linear, respectively, in the top view. The first tip cutting edge is convex in the top view, preferably in the form of an arc, and preferably has a radius of curvature of 0.2-1.6 mm.

[0037] The tip angle of the first cutting element is defined as the angle between the first forward cutting edge and the first backward cutting edge, and the tip angle is preferably less than or equal to 160°, or even more preferably 30°-80°.

[0038] The first forward cutting edge is preferably arranged to form an acute first entry angle when the turning tool moves along a direction perpendicular to the connecting axis and parallel to the rotation axis of the metal workpiece. Preferably, the first entry angle is 3-45°, and even more preferably 5-30°.

[0039] During the movement of the turning tool, the first cutting edge at the tip and the first forward cutting edge are in a cutting state, that is, in an active state.

[0040] No part of the turning tool is along the straight line connecting the first and second cutting edges.

[0041] According to one embodiment, measured along the connecting axis, the second cutting edge is located in front of the first cutting edge.

[0042] With such turning tools, more complex shapes can be machined. For example, a first roughing operation can be performed in longitudinal turning using a cutting element at a lower approach angle, and the remaining material can be removed using another cutting element.

[0043] The distance from the rear end defined by the connecting portion to the second cutting edge is greater than the distance from the rear end to the first cutting edge, wherein the distance is measured along a line parallel to the connecting axis. Preferably, this distance difference is at least 1 mm, more preferably 2-30 mm.

[0044] According to one embodiment, the first tool tip angle, defined as the angle between the first forward cutting edge and the first backward cutting edge, is an acute angle.

[0045] Such turning tools allow for the machining of more complex shapes. They also enable more feed directions, such as, for example, outwards. The first tool tip angle is typically measured in a top view. Preferably, the first tool tip angle is 25-80°, more preferably 30-60°.

[0046] According to one embodiment, a turning tool includes a forward surface, wherein at least two elements protrude from the forward surface in a forward direction, wherein a first protruding element of the protruding elements includes a first cutting element, and a second protruding element of the protruding elements includes a second cutting element.

[0047] The turning tool preferably includes a middle portion. The middle portion is located longitudinally between the connecting portion and the protruding element. The middle portion includes a forward surface. This forward surface faces away from the connecting portion.

[0048] Each of the protruding elements is preferably connected to the intermediate portion by one or more clamping devices. The clamping device preferably comprises one or more screws or bolts, each screw or bolt extending along an axis parallel to the connection axis.

[0049] In other words, each protruding element preferably includes one or more threads, wherein the one or more threads are in the form of a helix around an axis parallel to the connecting axis.

[0050] The protruding element is preferably in the form of a replaceable cutting head, each cutting head having a blade holder in which a cutting blade or turning blade is held or mounted.

[0051] The intermediate portion preferably extends primarily in a direction perpendicular to the connecting axis.

[0052] The middle portion connects the at least two forward-protruding elements to the connecting portion. The forward-protruding elements protrude in a direction away from the connecting portion and in a direction away from the forward surface.

[0053] Each of the forward-protruding elements has a longitudinal extension, that is, an extension in a direction parallel to the connecting axis.

[0054] The first protruding element includes the first cutting element, which is formed on the first protruding element. The second protruding element includes the second cutting element.

[0055] According to one embodiment, the at least two forward-protruding elements are spaced apart from the connecting axis.

[0056] Preferably, the at least two forward-protruding elements are spaced from the connecting axis by the same or substantially the same distance (i.e., within + / -10%).

[0057] According to one embodiment, the second tool tip angle, defined as the angle between the second forward cutting edge and the second backward cutting edge, is an acute angle.

[0058] Such turning tools allow for the machining of more complex shapes. They also enable more feed directions, such as, for example, outwards. The first tool tip angle is typically measured in a top view. Preferably, the second tool tip angle is 25-80°, more preferably 30-60°.

[0059] According to one embodiment, the first cutting element is in the form of a first turning insert, wherein the second cutting element is in the form of a second turning insert, wherein the first turning insert includes a first top surface and an opposite first bottom surface, wherein the second turning insert includes a second top surface and an opposite second bottom surface, wherein the first top surface includes a first rake surface, and wherein the second top surface includes a second rake surface.

[0060] Preferably, the first turning insert includes a first forward cutting edge and a first backward cutting edge.

[0061] The top surface includes the front cutting surface, and the bottom surface includes the mounting surface or the contact surface.

[0062] The first through hole for the first screw intersects with the first top surface and the first bottom surface.

[0063] The second through hole for the second screw intersects with the second top surface and the first bottom surface.

[0064] A first intermediate plane extends substantially midway between the first top surface and the first bottom surface, and a second intermediate plane extends substantially midway between the second top surface and the second bottom surface. Preferably, the first and second intermediate planes extend in parallel or substantially parallel planes.

[0065] According to one embodiment, a first cutting element is arranged such that when a turning tool is moved in a first direction parallel to the connecting axis, a first forward cutting edge forms a first entry angle of 3-45°, wherein a second cutting element is arranged such that when a turning tool is moved in a second direction opposite to the first direction, a second forward cutting edge forms a second entry angle of 3°-45°.

[0066] Such a turning tool can reduce wear. The first direction is preferably the forward direction. The second direction is parallel to the connecting axis.

[0067] According to one embodiment, the first cutting element is arranged such that when turning in a first direction, the first rearward cutting edge forms a first back clearance angle of 93°-135°.

[0068] With such a turning tool, the first cutting element can be used in more feed directions, such as facing outwards. With such a turning tool, more complex shapes can be machined.

[0069] According to one embodiment, the second cutting element is arranged such that when turning in the second direction, the second rearward cutting edge forms a second back clearance angle of 93°-135°.

[0070] With this type of turning tool, the second cutting element can be used in more feed directions, such as outward. More complex shapes can be machined using such a tool. The second direction is the backward direction.

[0071] According to one embodiment, the first cutting element and the second cutting element are arranged such that when turning in the first direction, the second cutting edge is in front of the first cutting edge.

[0072] With such turning tools, more complex shapes can be machined.

[0073] The first and second cutting edges are longitudinally spaced apart, with the connecting axis defining the longitudinal axis.

[0074] In this context, turning in the first direction means moving the turning tool in the forward direction along the connecting axis. The rear end of the turning tool is defined by the connecting portion.

[0075] According to one embodiment, a first cutting element and a second cutting element are arranged such that the first cutting element and the second cutting element can be used to turn a metal workpiece that can rotate in one direction about a rotation axis of the metal workpiece, wherein the rotation axis is arranged perpendicular to and intersects the connecting axis.

[0076] The first and second cutting elements can be used alternately for machining, i.e., turning, without any rotation of the turning tool.

[0077] According to one embodiment, the turning tool is arranged such that a cylindrical metal workpiece can be arranged between a first cutting element and a second cutting element, wherein the longitudinal axis of the metal workpiece is between the cutting elements (7, 8).

[0078] Preferably, the longitudinal axis is perpendicular to the connecting axis. The diameter of the cylindrical metal workpiece is preferably 16-500 mm, more preferably 20-200 mm.

[0079] According to one embodiment, the cross-section of the connecting portion is square or rectangular, or includes a tapered or substantially tapered portion.

[0080] The cross-section lies in a plane perpendicular to the connecting axis. The connecting portion preferably comprises a tapered or substantially tapered portion and an annular portion, such as preferably in the form of a polygonal hollow tapered interface with a flanged contact surface, for example according to ISO 26623-1:2014, or in the form of a hollow tapered portion with a flanged contact surface, for example according to DIN 69893, ISO 12164-1 or ISO 12164-1F.

[0081] The connecting portion is preferably arranged to allow for quick replacement; in other words, it allows for relatively rapid manual or automatic clamping and removal. Preferably, the connecting portion is arranged without threads. Preferably, the connecting portion is arranged without screw holes, bolt holes, or locating pin holes, or has fewer than three screw holes, bolt holes, or locating pin holes.

[0082] The cross-section of the connecting portion can be square or rectangular, wherein the cross-section lies in a plane perpendicular to the connecting axis. In this case, the connecting portion preferably has a length of 50-300 mm measured along the connecting axis. If the cross-section of the connecting portion is square, i.e., square in shape, the side length of the square is preferably 20 mm, 25 mm, 25.4 mm, or 32 mm.

[0083] The connecting parts are arranged to connect to, for example, a turret, a tool post, or a tool holder.

[0084] The connecting part is preferably a known connecting part. Therefore, the turning tool can be used on known types of CNC lathes. In other words, the CNC lathe does not need to be specially manufactured or modified to use the turning tool.

[0085] According to one embodiment, a turning method for a CNC lathe includes the following steps: providing a metal workpiece; providing a turning tool as described above; rotating the metal workpiece in one direction about its axis of rotation; moving the turning tool in the first direction such that a first cutting edge is in a cutting state; moving the turning tool in one direction such that the first cutting edge moves away from the metal workpiece and a second cutting edge moves toward the metal workpiece; moving the turning tool in a second direction such that a second forward cutting edge is in a cutting state at a second approach angle of 5–45°, wherein the second direction is the opposite or substantially opposite direction to the first direction.

[0086] This turning method is suitable for CNC lathes, i.e., computerized or computerized numerical control lathes, that is, any CNC machine tool suitable for turning, such as turning lathes, multi-tasking machine tools, milling and turning machines, or sliding head machine tools. A metal workpiece is provided. The metal workpiece includes an outer surface, which is a radial outer surface. This radial outer surface faces away from the axis of rotation. The turning method is to turn the radial outer surface, i.e., external turning. The metal workpiece extends between a first end and a second end. The metal workpiece is held by a clamping device. The clamping device holds the metal workpiece and is at least partially controlled and driven by a motor or spindle.

[0087] The clamping device can be in the form of a chuck, a face driver, or a three-jaw chuck, and may include a tailstock. The spindle head end of the machine tool is preferably located at the first end of the metal workpiece. The second end of the metal workpiece, opposite the first end, can be a free end. Alternatively, the second end may contact the tailstock.

[0088] The method includes the step of rotating a metal workpiece in one direction about its axis of rotation. This direction can be clockwise or counterclockwise. The axis of rotation is parallel to the central axis of an imaginary circle or cylinder.

[0089] The method includes the step of moving the turning tool in a first direction, i.e., a first feed direction. The first direction may preferably be parallel to the axis of rotation, also referred to as longitudinal turning. The step is included in a first pass, defined as the movement between entering and exiting the cutting edge. The first pass is not necessarily a linear movement of the first cutting element. When turning in the first direction, the first cutting edge is in a cutting state. The machined surface is formed by the first cutting edge.

[0090] Preferably, the first cutting element includes a first forward cutting edge and a first backward cutting edge, wherein the first cutting tip cutting edge separates the first forward cutting edge and the first backward cutting edge, and connects the first cutting tip cutting edge and the first backward cutting edge, wherein when turning in a first direction, the first forward cutting edge forms a first entry angle with an acute angle.

[0091] After or during cutting, the turning tool is moved such that the first cutting edge moves away from the metal workpiece and the second cutting edge moves towards the metal workpiece. During at least a portion of this movement, neither the first nor the second cutting element is in a cutting state; that is, neither the first nor the second cutting element performs metal cutting during this movement.

[0092] The movement of the turning tool is preferably linear, meaning the turning tool moves linearly. The movement of the turning tool can preferably occur in a direction perpendicular to both the connecting axis and the rotation axis.

[0093] The method includes a turning step in a second direction. The second direction is the opposite or substantially opposite direction to the first direction. For example, the first and second directions may be parallel to the axis of rotation but in opposite directions. The step is included in a second feed, defined as the movement between entry and exit points of the cutting process. The second feed is not necessarily a linear movement of the first cutting element. The machined surface is formed by a second cutting edge. The second cutting edge and the second forward cutting edge are in a cutting state such that the second forward cutting edge is in a cutting state with a second entry angle of 5° to 45°, or even more preferably 5° to 30°.

[0094] When turning in the first direction, the second cutting element is inactive. When turning in the second direction, the first cutting element is inactive.

[0095] Preferably, the method includes the step of setting the connecting axis to be parallel to the rotation axis.

[0096] Preferably, the second direction is the opposite or substantially opposite direction to the first direction.

[0097] Preferably, the method further includes the following additional step: wherein when turning in the first direction, the first entry angle of the first forward cutting edge is set to an acute angle, preferably 3°-45°, or even more preferably 5°-30°. The first direction is parallel to the axis of rotation.

[0098] Preferably, when turning in the second direction, the second forward cutting edge is in the cutting state with an acute second entry angle, preferably 5°-45°.

[0099] During the second feed, the second backward cutting edge preferably has a back clearance angle that forms an obtuse angle. Preferably, the back clearance angle is 91°-135°, more preferably 93°-120°.

[0100] During the first pass, the first backward cutting edge preferably forms a back clearance angle of at least 91°.

[0101] Preferably, the step of moving the turning tool so that the first cutting edge moves away from the metal workpiece and the second cutting edge moves towards the metal workpiece is a linear motion. This linear motion is preferably in a direction perpendicular to the connecting axis.

[0102] Preferably, the steps of moving the turning tool away from the metal workpiece and moving the second cutting edge toward the metal workpiece are performed without rotating the turning tool about the connecting axis. Therefore, the indexing time can be shorter compared to rotary movement.

[0103] Preferably, the turning tool does not rotate about the connecting axis during the first and second passes or between the first and second passes. Preferably, the turning tool 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 two.

[0104] Preferably, the method includes the step of: during the second pass, turning at least a portion of the surface machined or turned during the first pass.

[0105] Preferably, the method includes the additional step of arranging the first and second cutting edges at the tip such that, during all steps of the method, the cutting edges at the tip are spaced apart at a constant distance along the axis of rotation.

[0106] Preferably, the method includes the following additional step: setting the connecting axis to be parallel to the axis of rotation.

[0107] Preferably, the method includes the step of clamping a metal workpiece with the aid of a collet chock, wherein the metal workpiece is a bar with a diameter less than or equal to 50 mm.

[0108] Preferably, the distance from the clamping device to the second cutting edge is shorter than the distance from the clamping device to the first cutting edge.

[0109] Preferably, during the first feed, the second cutting edge is positioned in front of the first cutting edge. Preferably, during the second feed, the first cutting edge is positioned in front of the second cutting edge. "In front" should be understood as being in front along the axis of rotation in the feed direction.

[0110] Preferably, the second feed is 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 can be an external surface or an internal surface, i.e., a surface inside the hole. Preferably, the first surface is an external surface, i.e., a radially outer surface.

[0111] Preferably, the second direction is in the direction away from the outer corner of the metal workpiece. Preferably, the corner is at least partially formed by the second cutting element. 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.

[0112] According to one embodiment, the computer program has instructions that, when executed by a CNC lathe, cause the CNC lathe to perform the steps according to the method described above.

[0113] The computer program or computer program product may be included in a CAM software product, i.e., software used for computer-aided manufacturing. The computer program may be in the form of a computer-readable medium, such as a USB stick, CD-ROM, or data stream. Attached Figure Description

[0114] The invention will now be explained in more detail through a description of embodiments thereof and with reference to the accompanying drawings.

[0115] Figure 1 This is a perspective view of a turning tool according to one embodiment.

[0116] Figure 2 yes Figure 1 A top view of a turning tool.

[0117] Figure 3 yes Figure 1 The front view of the turning tool in the image.

[0118] Figure 4 yes Figure 1 A side view of a turning tool.

[0119] Figure 5 yes Figure 1 A top view of the turning tool and the metal workpiece.

[0120] Figure 6 yes Figure 1 Another top view of the turning tool and the metal workpiece.

[0121] Figure 7 yes Figure 1 Another top view of the turning tool and the metal workpiece.

[0122] Figure 8 This is a schematic diagram of the movement of a turning tool in the first direction.

[0123] Figure 9 This is another schematic diagram showing the movement of the turning tool in the second direction.

[0124] Figure 10 It is a schematic cross-sectional view showing the first cutting element, the second cutting element, and the rotating metal workpiece.

[0125] All turning tools in the diagram are drawn to scale. Detailed Implementation

[0126] Now for reference Figures 1-7A turning tool 1 according to one embodiment is shown. The turning tool 1 includes a connecting portion 3. The connecting portion 3 extends along a connecting axis A2, which defines the longitudinal axis of the turning tool 1. The connecting portion defines the rear end of the turning tool 1. The turning tool 1 includes a first cutting element 7 in the form of a first turning insert 7 and a second cutting element 8 in the form of a second turning insert 8. For example, Figure 2 As shown, the first turning insert 7 includes a first forward cutting edge 12, a first backward cutting edge 14, and a first tip cutting edge 5. The first tip cutting edge 5 is the portion of the first turning insert 7 closest to the connecting axis A2. The second turning insert 8 includes a second tip cutting edge 6, a second forward cutting edge 13, and a second backward cutting edge 15. The first tip angle, defined as the angle between the first forward cutting edge 12 and the first backward cutting edge 14, is an acute angle. The second tip angle, defined as the angle between the second forward cutting edge 13 and the second backward cutting edge 15, is an acute angle. For example, in... Figure 2 As seen, measured along or parallel to the connecting axis A2, the second cutting edge 6 is located in front of the first cutting edge 5. "In front" is defined as away from the connecting portion 3 and towards the first turning insert 7 and the second turning insert 8.

[0127] For example Figure 3 As seen, 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 top surface 21 and an opposite second bottom surface. The first top surface 20 includes a first rake surface, and the second top surface 21 includes a second rake surface. Figure 3 As shown, the first cutting insert 7 and the second cutting insert 8 intersect an imaginary circle or cylinder C1, the central axis A3 of which is parallel to the connecting axis A2. The first cutting insert 7 is inclined relative to the second cutting insert 8 at an angle ω, wherein the angle ω is measured about the central axis A3 of the imaginary circle C1. The first top surface 20 faces a direction perpendicular to or substantially perpendicular to the connecting axis.

[0128] For example Figure 1 As seen, the turning tool 1 includes a forward surface 42, i.e., a surface facing away from the connecting portion 3. Two elements 30 and 31 are in the form of replaceable cutting heads 30 and 31, which project forward from the forward surface 42. The first cutting head 30 includes a first turning insert 7, meaning the first cutting head includes an insert holder in which the first turning insert 7 is mounted. The second cutting head 31 includes a second cutting element 8. The cutting heads 30 and 31 are spaced apart from the connecting axis A2.

[0129] The connecting portion 3 defines the rear end of the turning tool 1 and is adapted for insertion into a machine tool interface (not shown), which preferably includes a cavity or recess (not shown). For example... Figure 1The connecting portion 3 shown includes a basically tapered section or a basically tapered or conical section. This connecting portion is known in the field of metal cutting tools as CoromantCapto®. Other types of connecting portions are also possible, such as the known square shank type. For example, if the connecting portion is a square shank type, the cross-section of the connecting portion perpendicular to the connecting axis is square or rectangular. Furthermore, for such turning tools, the connecting axis is parallel to the connecting axis A2 in Figure 4 and is 5–20 mm below the connecting axis A2.

[0130] Figure 5 The first machining step is shown. The metal workpiece 2 rotates in one direction about its axis of rotation A1. The turning tool 1 moves in a first direction 17, which is parallel to the connecting axis A2 and parallel to the axis of rotation A1 of the metal workpiece 2. The first direction 17 is a forward direction, that is, in the direction away from the connecting part 3 and in the direction facing the forward surface 42. The top surface of the first turning insert 7 is... Figure 5 The first cutting edge 5 is the center point facing the observer. The machined surface is formed by the first cutting edge 5; in other words, the first cutting edge 5 is the surface-generating cutting edge. The first turning insert 7 is arranged such that the first forward cutting edge 12 forms a first entry angle α of 3-45° acute. The first backward cutting edge 14 forms a first clearance angle γ of 93°-135° obtuse. The second turning insert 8 is separated from the metal workpiece 2. When the turning tool 1 is moved in the first direction 17, the second cutting edge 6 is in front of the first cutting edge 5. Figure 5 As shown, the turning tool 1 is arranged such that the cylindrical metal workpiece 2 is arranged between the first turning insert 7 and the second turning insert 8, wherein the axis of rotation A1 is the longitudinal axis A1 of the first metal workpiece (2), which is located between the turning inserts 7 and 8.

[0131] Figure 6 It shows Figure 5 The steps following the steps shown. The turning tool 1 moves in direction 19, causing the first cutting edge 5 to move away from the metal workpiece 2 and the second cutting edge 6 to move towards the metal workpiece 2. The turning tool 1 moves in direction 19, which is perpendicular to the connecting axis A2 and the rotation axis A1. The movement is linear.

[0132] Figure 7 It shows Figure 6The steps following the steps shown. The turning tool 18 moves in the second direction 18. The second direction 18 is in the opposite direction to the first direction 17. The second forward cutting edge 13 forms a second entry angle β with an acute angle of 3° to 45°. The second backward cutting edge 15 forms a second clearance angle δ with an obtuse angle of 93° to 135°. The first turning insert 7 separates from the metal workpiece 2. The first cutting edge 5 is located in front of the second cutting edge 6 in the second direction 18. At least a portion of the surface machined by the first turning insert 7 in the first step (as shown in Figure 5) is machined by the second turning insert 8.

[0133] Figure 8 An example of the first step of a turning method using a CNC lathe (not shown) is illustrated. A metal workpiece 2 rotates about its axis of rotation A1 in a direction 50. The connecting portion 3 of the turning tool 1 is connected to the CNC lathe (not shown), more specifically, to the machine tool interface. The connecting axis A2 is perpendicular to the axis of rotation A1. The turning tool 1 moves in a first direction 17 such that the first cutting edge 5 is in a cutting state, and the first forward cutting edge forms an acute entry angle. The first backward cutting edge 14 forms an obtuse clearance angle. A second cutting insert 8 and a third cutting insert 9 separate from the metal workpiece 2. The second cutting edge is located in front of the first cutting edge 5 in the first direction 17. The first direction is parallel to the axis of rotation A1.

[0134] Compared to those described above, metal workpieces can have different shapes. Metal workpieces can be bars, hollow bars, or any other shape that is rotationally symmetric or substantially rotationally symmetric about its axis of rotation. Machinable shapes can have different constructions than those described above. For example, the shape can have not just one sidewall, but two sidewalls, i.e., surfaces in a plane perpendicular to the axis of rotation. In other words, turning tools can be used to machine external grooves.

[0135] Figure 8 This is a schematic diagram of a turning tool moving in a first direction 17, where the first cutting element 7 is in a cutting state. The first direction 17 is the feed direction. The first forward cutting edge forms a first entry angle α of 5–45°, and the first backward cutting edge forms a back clearance angle γ of at least 91°. The second cutting element 8 is separated from the metal workpiece 2. The machined surface 25 is formed by the first cutting element 7. More specifically, the surface 25 is formed by the first cutting edge 5.

[0136] Figure 9 This is another schematic diagram showing the movement of the turning tool in the second direction 18, where the second cutting element 8 is in a cutting state. The second forward cutting edge is in a cutting state with a second entry angle β of 5–45°, and the second backward cutting edge forms an obtuse clearance angle δ. The second bottom surface faces the observer.

[0137] Figure 8 The first processing step is shown, followed by... Figure 9 The steps are shown. In Figure 9 In the middle, the second cutting element 8 is located at the axis of rotation A1 and... Figure 8 On the opposite side of the first cutting element 7, and the first top surface faces the direction opposite to the second top surface.

[0138] Figures 8-9 One end of the metal workpiece 2 is held by a clamping device 60. The clamping device 60 is connected to and driven by a rotating or rotatable spindle (not shown), which is part of a CNC lathe (not shown). The clamping device can be, for example, a chuck, a three-jaw chuck, or an end-face drive. The distance from the clamping device 60 to the second cutting edge 6 is shorter than the distance from the clamping device 60 to the first cutting edge 5, wherein the distance is measured along a line parallel to the axis of rotation A1. Figures 8-9 In the first direction 17, the clamping device 60 is away from the clamping device, and in the second direction 18, the clamping device is towards the clamping device. Alternatively (not shown), the first direction 17 is towards the clamping device 60, while the second direction 18 is away from the clamping device. Therefore, the first direction 17 and the second direction 18 are in opposite directions along the axis of rotation A1. Thus, opposite directions can be understood as towards or away from the clamping device, or towards or away from a longitudinal end of the metal workpiece. Therefore, the first direction and the second direction are not necessarily linear and parallel to the axis of rotation.

[0139] Figure 9 The diagram illustrates 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 lies in a plane perpendicular to the axis of rotation A1. The corner or shoulder is the intersection between a surface concentric with the axis of rotation and a second surface perpendicular to the axis of rotation. The corner is a 90° angle. Preferably, the corner is entirely formed by the second cutting element, wherein the turning tool moves toward the axis of rotation A1 immediately before moving in the second direction 18.

[0140] Figure 10This is a schematic diagram showing a first cutting element 7 in the form of a first cutting insert 7, a second cutting element 8 in the form of a second cutting insert 8, and a rotating metal workpiece in cross-section. The first cutting insert 7 and the second cutting insert 8 are arranged according to the embodiment described above. The first cutting insert 7 includes a first top surface 20 and a first bottom surface 22, both of which are horizontal or substantially horizontal. The second cutting insert 8 includes a second top surface 21 and a second bottom surface 23, both of which are horizontal or substantially horizontal. A first intermediate plane P1 is located at the midpoint or substantially midpoint between the first top surface 20 and the first bottom surface 22. The first intermediate plane P1 is parallel or substantially parallel to the first bottom surface 22. A second intermediate plane P2 is arranged in a corresponding manner. The first intermediate plane P1 and the second intermediate plane P2 are arranged in parallel planes. The metal workpiece 2 rotates about its axis of rotation A1 in one direction 50. The first cutting insert 7 and the second cutting insert 8 are located on opposite sides of the axis of rotation A1. The first top surface 20 is facing upwards in the figure, and the second top surface 21 is facing downwards in the figure. When the first cutting insert 7 is in the cutting state, the second cutting insert 8 is separated from the metal workpiece 2.

[0141] Preferably, the first turning insert 7 and the second turning insert 8 are made of a wear-resistant material, preferably cemented carbide. Preferably, the first top surface 20 and the second top surface 21 include a chip forming device or a chip breaking device (not shown). Preferably, the distance from at least a portion of the chip forming device or chip breaking device to the mid-plane of the respective turning insert is greater than the distance from the cutting edge bordering the top surface to the mid-plane. In other words, the top surface 20 of the first turning insert and the top surface 21 of the second turning insert include at least one protrusion that is higher than or above the cutting edge in a side view. This makes the turning inserts more suitable for turning.

[0142] The first turning insert 7 and the second turning insert 8 are preferably designed such that the first forward cutting edge 12 is inclined downward at a gradually increasing distance from the first cutting edge 5, i.e., inclined towards the first bottom surface 22. The second forward cutting edge 13 is preferably arranged in a corresponding manner. In this way, chip control is further improved.

[0143] The forward cutting edge and the backward cutting edge are forward and backward in their respective feed directions, and not necessarily forward or backward relative to the forward or backward direction of the turning tool itself.

Claims

1. A turning tool (1), the turning tool (1) comprising a connecting portion (3). in, The connecting portion (3) extends along the connecting axis (A2), The connecting axis (A2) defines the longitudinal axis of the turning tool (1). The turning tool (1) includes a first cutting element (7) and a second cutting element (8). The first cutting element (7) includes a first cutting edge (5); The second cutting element (8) includes a second cutting edge (6), which separates the second forward cutting edge (13) and the second backward cutting edge (15) and connects the second forward cutting edge (13) and the second backward cutting edge (15). The first cutting element (7) includes a first top surface (20). The second cutting element (8) includes a second top surface (21). Its features are, The first cutting element (7) and the second cutting element (8) intersect with an imaginary circle or cylinder (C1), the central axis (A3) of which is parallel to or coincides with the connecting axis (A2). The first cutting element (7) is inclined at an angle (ω) relative to the second cutting element (8). The tilt angle (ω) is measured around the central axis (A3) of the imaginary circle (C1). The first top surface (20) faces a direction perpendicular to or substantially perpendicular to the connecting axis (A2), and the first cutting element (7) includes a first forward cutting edge (12) and a first backward cutting edge (14). Wherein, the first cutting edge (5) is the first cutting edge tip (5); The first cutting edge (5) separates the first forward cutting edge (12) and the first backward cutting edge (14) and connects the first forward cutting edge (12) and the first backward cutting edge (14). The first cutting element (7) is arranged such that when the turning tool (1) is moved in a first direction (17) parallel to the connecting axis (A2), the first forward cutting edge (12) forms a first entry angle (α) of 3-45°. The second cutting element (8) is arranged such that when the turning tool (1) is moved in a second direction (18) opposite to the first direction (17), the second forward cutting edge (13) forms a second approach angle (β) of 3°-45°. The linear motion of the turning tool enables the change or rotation from the first cutting element to the second cutting element.

2. The turning tool (1) according to claim 1. in, Measured along the connecting axis (A2), the second cutting edge (6) is located in front of the first cutting edge (5).

3. The turning tool (1) according to claim 1 or 2. in, The first tool tip angle, defined as the angle between the first forward cutting edge (12) and the first backward cutting edge (14), is an acute angle.

4. The turning tool (1) according to any one of claims 1-2. in, The turning tool (1) includes a forward surface (42), wherein at least two protruding elements (30, 31) protrude from the forward surface (42) in the forward direction. The first protruding element in the protruding element (30) includes the first cutting element (7). The second protruding element in the protruding element (31) includes the second cutting element (8).

5. The turning tool (1) according to claim 4. in, The forward-protruding at least two elements (30, 31) are spaced apart from the connecting axis (A2).

6. The turning tool (1) according to any one of claims 1-2 in, The second tool tip angle, defined as the angle between the second forward cutting edge (13) and the second backward cutting edge (15), is an acute angle.

7. The turning tool (1) according to any one of claims 1-2 in, The first cutting element (7) is in the form of a first turning insert (7). The second cutting element (8) is in the form of a second turning insert (8). The first turning insert (7) includes a first top surface (20) and an opposite first bottom surface (22). The second turning insert (8) includes a second top surface (21) and an opposite second bottom surface (23). Wherein, the first top surface (20) includes a first front blade surface, The second top surface (21) includes the second front blade surface.

8. The turning tool (1) according to any one of claims 1-2 in, The first cutting element (7) is arranged such that when turning in the first direction (17), the first back cutting edge (14) forms a first back clearance angle (γ) of 93°-135°.

9. The turning tool (1) according to any one of claims 1-2. in, The second cutting element (8) is arranged such that when turning in the second direction (18), the second back cutting edge (15) forms a second back clearance angle (δ) of 93°-135°.

10. The turning tool (1) according to any one of claims 1-2 in, The first cutting element (7) and the second cutting element (8) are arranged such that when turning in the first direction (17), the second cutting edge (6) is in front of the first cutting edge (5).

11. The turning tool (1) according to any one of claims 1-2. in, The first cutting element (7) and the second cutting element (8) are arranged such that the first cutting element (7) and the second cutting element (8) can be used to turn a metal workpiece (2), wherein the metal workpiece (2) can rotate in one direction about a rotation axis (A1) of the metal workpiece (2), wherein the rotation axis (A1) is arranged to be perpendicular to the connecting axis (A2) and intersects the connecting axis (A2).

12. The turning tool (1) according to any one of claims 1-2. in, The turning tool (1) is arranged such that a cylindrical metal workpiece (2) can be arranged between the first cutting element (7) and the second cutting element (8), wherein the longitudinal axis (A1) of the metal workpiece (2) is located between the cutting elements (7, 8).

13. The turning tool (1) according to any one of claims 1-2 in, The cross-section of the connecting portion (3) is square or rectangular, or includes a conical or basically conical portion.

14. A turning method on a CNC lathe, comprising the following steps: Provide metal workpieces (2). A turning tool (1) according to any one of claims 1-13 is provided. The metal workpiece (2) is rotated about its axis of rotation (A1) in one direction (30); The turning tool (1) is moved in the first direction (17) such that the first cutting edge (5) is in a cutting state and the first forward cutting edge (12) forms a first entry angle (α) of 3-45°. The turning tool (1) is moved in one direction (19) such that the first cutting edge (5) moves away from the metal workpiece (2) and the second cutting edge (6) moves towards the metal workpiece (2). The turning tool (1) is moved in the second direction (18) so that the second forward cutting edge (13) is in a cutting state with a second entry angle (β) of 3 – 45°. The second direction (18) is the opposite or substantially opposite direction of the first direction (17).

15. A computer-readable medium having instructions that, when executed by a CNC lathe, cause the CNC lathe to perform the steps of claim 14.

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