TURNING METHOD FOR COMPUTERIZED NUMERICAL CONTROL (CNC) LATHES AND TURNING TOOLS

Abstract

A turning method for a computerized numerically controlled lathe includes providing a turning tool (1) including a cutting portion (2), the cutting portion (2) including a first nose portion (10), the first nose portion (10) including a first cutting edge (11), a second cutting edge (12), and a convex nose cutting edge (13) connecting the first and second cutting edges (11, 12), the first and second cutting edges (11, 12) being straight or substantially straight in a top view; providing a metal workpiece (31); The method includes rotating the workpiece (31) about the workpiece axis of rotation (R2); and making a first pass (36) such that the first cutting edge (11) is active and the second cutting edge (12) is inactive, such that a first machined surface (38) is generated by the convex nose cutting edge (13), and such that during at least a portion of the first pass (36), the leading edge angle (K) and the angle (β) that the first cutting edge (11) forms with respect to the workpiece axis of rotation (R2) are simultaneously changed. [Selection diagram] Figure 53

Description

[Technical field]

[0001] The present invention relates to the technical field of metal cutting. More specifically, the invention is in the field of turning metal workpieces by using a computer or computerized numerical control (CNC) machine. More specifically, the present invention relates to a turning method, an automated computer-implemented method, and a turning tool. [Background technology]

[0002] Many turning methods are known for turning metal workpieces using CNC lathes. Traditionally, the orientation of the turning tool with respect to the workpiece remains constant during machining, and the turning operation is performed in two linear axes. The entering angle, also known as the set angle, traditionally cannot be selected by any means other than by changing the turning tool.

[0003] No. 6,715,386 B2 describes how the cutting insert can be set at various angles. As shown in Fig. 10, turning (i.e., rotating) of the cutting insert is performed during a first machining sequence and a second machining sequence.

[0004] The inventors have determined that turning methods can be further improved, in particular, the inventors have determined that there is a need for improved tool life and / or chip control. Summary of the Invention

[0005] The inventors have found that there is a need for an improved method of improving tool life and / or chip control. In particular, the inventors have found that there is a need for an improved method when machining predefined features having complex geometries, in particular when machining external grooves. The inventors have found that in such cases, it is preferable to vary the cutting angle to reduce the risk of interference between the inactive part of the turning tool and the metal workpiece and / or to improve chip control and / or tool life. The inventors have further found that there is a need for a turning method that reduces the risk of vibration. The inventors have further found that there is a need for a turning method that maximizes the cutting time of a CNC lathe, thereby reducing manufacturing costs. Such a turning method can reduce the risk of rapid changes in cutting forces, e.g. from rapid changes in cutting depth, and therefore extend tool life. Such a turning method can allow components or component features having complex geometries, such as grooves, to be machined using a single turning tool, thereby reducing machining time.

[0006] This object is achieved, at least in part, by a turning method for a computerized numerically controlled lathe, the method including providing a turning tool including a cutting portion, the cutting portion including a first nose portion including a first cutting edge, a second cutting edge, and a convex nose cutting edge connecting the first and second cutting edges, the first and second cutting edges being straight or substantially straight in a top plan view, providing a metal workpiece, rotating the metal workpiece about an axis of rotation of the workpiece, and making a first pass such that the first cutting edge is active and the second cutting edge is inactive, a first machined surface is generated by the convex nose cutting edge, and during at least a portion of the first pass, a leading edge angle and an angle that the first cutting edge forms with respect to the axis of rotation of the workpiece are simultaneously changed.

[0007] The method is therefore a turning method, preferably an outer turning method in which a rotationally symmetric surface is formed. The method is for a computerized numerically controlled (CNC) lathe. A turning tool is provided. The turning tool comprises a cutting part, preferably in the form of a cutting insert, in the form of a turning insert. The cutting part comprises a first nose part. Preferably, the cutting part comprises a second nose part. The first nose part comprises a first cutting edge, a second cutting edge and a convex nose cutting edge connecting the first and second cutting edges. The first cutting edge, the second cutting edge and the nose cutting edge connect a top surface and a side surface. The top surface is arranged to function as a rake surface. The top surface preferably comprises chip breaking means, preferably in the form of one or more protrusions and / or recesses. The first and second cutting edges are straight or substantially straight or linear in top view. Preferably, a rotationally symmetric or substantially rotationally symmetric metal workpiece is provided. The metal workpiece is clamped to the CNC lathe by clamping means such as clamping jaws. The metal workpiece may be clamped at one end or at opposite ends.

[0008] The metal workpiece is rotated about its axis of rotation, preferably in strictly one direction about its axis of rotation.

[0009] The first cutting edge is preferably active, i.e., in a cutting state, for the entire cutting time during the first pass.

[0010] A path can be understood as a turning sequence, which can be defined in the long term as the time between the start of the cut and the end of the cut, i.e. the time span during which the chips are removed from the metal workpiece, and the path can be further defined as the way in which the turning is performed, geometrically or spatially, more specifically the way in which the cutting part of the turning tool moves with respect to the metal workpiece, from the start of the cut to the end of the cut.

[0011] The phrase "causing the first cutting edge to be active and the second cutting edge to be inactive" may alternatively be articulated as "the first cutting edge is in front of the second cutting edge during the first pass."

[0012] During the first pass, or at least a portion of the first pass, the first cutting edge is active, i.e., cuts metal, and the second cutting edge is inactive, i.e., does not cut metal. A first machined surface is generated by the convex nose cutting edge. During at least a portion of the first pass, the leading edge angle and the angle that the first cutting edge forms with respect to the axis of rotation of the workpiece change or vary simultaneously, i.e., synchronously.

[0013] In other words, the entering angle changes or varies and the angle that the first cutting edge forms with respect to the axis of rotation of the workpiece changes or varies.

[0014] The cutting angle is defined as the angle between the directions of movement of the surface generating points of the first cutting edge and the nose cutting edge.

[0015] The cutting angle is preferably from 5 to 140°, even more preferably from 20 to 110°.

[0016] The cut angle may be constant at one or more locations during the first pass.

[0017] The angle that the first cutting edge forms with respect to the axis of rotation of the workpiece preferably changes at the same time that the lead angle changes during the first pass, in other words, each of the angles preferably changes synchronously during the first pass.

[0018] The respective variation or change of said angle may be achieved by rotation or movement of the axis of rotation of the workpiece. Alternatively and preferably, the respective variation of said angle is achieved by rotation or movement of the turning tool about the axis of rotation of the tool. The axis of rotation of the tool is preferably perpendicular or substantially perpendicular to a plane containing the top or rake face of the cutting part. The top or rake face is preferably not a plane. However, a plane may be defined which substantially contains the top or rake face.

[0019] The first pass is defined as from the beginning of the cut to the end of the cut, preferably from when the nose cutting edge begins the cut until the nose cutting edge finishes the cut. The location on the metal workpiece where the cut begins is away from the location where the cut ends.

[0020] The depth of cut during the first pass may be constant. Alternatively, the depth of cut may vary during the first pass.

[0021] During the first pass the cutting speed is preferably constant or substantially constant, preferably between 40 and 1500 m / min, even more preferably between 50 and 300 m / min.

[0022] The first pass preferably starts with a deeper cut depth and preferably ends with a shallower cut depth. Preferably, the cut depth in the middle of the first pass is preferably constant, preferably 0.2 to 15 mm, even more preferably 0.4 to 4 mm. The middle portion is preferably 50 to 99% of the first pass in chronological order.

[0023] In one embodiment, the first pass is a non-linear first pass.

[0024] Such methods allow features having complex shapes to be fabricated in a shorter time.

[0025] The method includes creating a first pass or tool path that is non-linear, meaning that the machined surface produced from the first pass is not perfectly cylindrical, conical or flat.

[0026] The first pass being non-linear means that the generated surface is non-cylindrical and / or non-conical and / or non-planar. The generated surface may comprise a combination or set of complementary surfaces, such as, for example, cylindrical surfaces, and / or planar surfaces, and / or concave surfaces, and / or convex surfaces. Preferably, the generated surface comprises a cylindrical surface concentric with the rotation axis of the metal workpiece and a concave surface. In other words, the non-linear first pass preferably comprises linear sections, such as where a cylindrical surface is generated, and curved sections, such as where a concave surface is generated.

[0027] The first cutting edge is preferably active, i.e., in a cutting state, for the entire cutting time during the non-linear first pass.

[0028] According to one embodiment, the method further includes increasing the entering angle and decreasing the surface generating feed rate during at least a portion of the first pass.

[0029] Such a turning method reduces the risk of interference or crashing, in other words the risk of contact between the non-cutting part of the turning tool and the metal workpiece, and allows more complex shapes to be machined.

[0030] Such turning methods further improve chip control because a smaller lead angle at the earlier stages of cutting provides a chip direction that is directed relatively further away from the axis of rotation of the metal workpiece, which can be an advantage when machining complex shapes such as external grooves.

[0031] Such a turning method allows for improved tool life, since the maximum chip thickness varies less than if the surface-generating feed were constant. A further aspect that the inventors have found is that a relatively small cutting angle is favorable for tool life, and a large cutting angle is favorable, at least in general, for reducing the risk of collision, which generally increases with the progression of the pass. Such a turning method therefore reduces the risk of interference or crashing. In other words, the risk of contact between the non-cutting part of the turning tool and the metal workpiece is reduced. Such a turning method allows for the machining of more complex shapes.

[0032] The surface generating feed rate is the velocity. The surface generating feed rate may preferably be 0.05 to 1.2 mm / rev. The surface generating point of the nose cutting edge preferably moves along the nose cutting edge. However, this effect is usually small.

[0033] When the cutting angle varies, the distance that the surface generating point of the nose cutting edge moves per revolution can be specified as the surface generating feed rate, and this distance can be found as the distance that the surface generating point of the nose cutting edge moves per revolution of the metal workpiece.

[0034] The machined surface has a corrugated and / or wavy structure, the distance between each adjacent top or tip being equal to the feed rate that creates the surface.

[0035] The results of such a method can be seen, for example, in a machined component where the distance between each of the feed marks, such as the leading edge, is shorter at or decreases towards the end of the pass.

[0036] During at least a portion of the first pass, the lead angle preferably increases simultaneously, i.e. synchronously, with the speed of the nose cutting edge, or more precisely, the speed of the surface generating point of the nose cutting edge, decreasing, in other words, preferably the lead angle increases simultaneously with the surface generating feed rate decreasing.

[0037] Alternatively, the cutting angle may be increased incrementally, e.g. by a fixed amount, e.g. by 1° or 2° at the same time as the feed rate is decreased incrementally, e.g. by a fixed amount or multiple of a fixed amount, e.g. by 0.001 or 0.005 mm / rev, etc.

[0038] According to one embodiment, the cutting angle and the angle that the first cutting edge forms with respect to the axis of rotation of the workpiece vary continuously.

[0039] Such smooth, stepless, or seamless variation of each of the angles has been found by the inventors to improve the quality of the machined surface.

[0040] The cutting angle may vary or change continuously, ie without interruption, or in steps.

[0041] The angle that the first cutting edge forms with respect to the axis of rotation of the workpiece may vary or change continuously, i.e., without interruption, or in steps.

[0042] According to one embodiment, the lead angle and the angle that the first cutting edge forms with respect to the axis of rotation of the workpiece are changed by rotation of the turning tool about the axis of rotation of the tool; The axis of rotation of the tool is perpendicular or substantially perpendicular to the axis of rotation of the workpiece.

[0043] With such a turning method, where the axis of rotation of the tool is perpendicular to the axis of rotation of the workpiece, the variation in angle may be achieved by the same amount of variation of the machine spindle to which the turning tool is connected.

[0044] By "substantially vertical" it is meant that the axis of rotation of the tool is within 15° of being perpendicular to the axis of rotation of the workpiece.

[0045] Preferably, the turning tool is elongated along the axis of rotation of the tool, in other words the turning tool is more elongated along the axis of rotation of the tool than along an axis perpendicular to the axis of rotation of the tool.

[0046] Preferably, the upper surface of the cutting portion is connected to the first cutting edge, the second cutting edge and the nose cutting edge, the upper surface being disposed in a plane perpendicular or substantially perpendicular to the axis of rotation of the tool, the upper surface facing away from the connection portion of the turning tool.

[0047] In such a way the risk of vibration is reduced.

[0048] Preferably, rotation of the turning tool about its axis of rotation during the first pass is in one direction only, ie only clockwise or only counterclockwise.

[0049] If the turning method includes a second pass, such as a non-linear second pass, the direction of rotation of the turning tool about the tool's axis of rotation is preferably opposite with respect to the direction of rotation during the first pass.

[0050] For a metal workpiece, the direction of rotation about the workpiece's axis of rotation is the same during both the first and second passes.

[0051] Preferably, the rotation of the turning tool about its axis of rotation during the first pass is between 50 and 200°, even more preferably between 70 and 160°.

[0052] According to one embodiment, the method further includes moving an axis of rotation of the tool relative to an axis of rotation of the workpiece during at least a portion of the first pass.

[0053] Such a turning method makes it easier to carry out the turning method compared to when the rotating shaft of the tool and / or the metal workpiece are moved.

[0054] In other words, the movement of the turning tool relative to the metal workpiece comprises a movement of the tool's axis of rotation relative to the workpiece's axis of rotation. The movement of the tool's axis of rotation is preferably a translational movement. The movement preferably comprises a non-linear movement. The workpiece's axis of rotation does not move.

[0055] According to one embodiment, the method further includes moving the turning tool toward an axis of rotation of the workpiece during at least a portion of the first pass.

[0056] With such a turning process, the first machined surface becomes the exterior surface, which may include internal corners and / or grooves and / or pockets and / or concave surfaces.

[0057] The internal corner is less than 180°, preferably 90°+ / -10°. The 90° internal corner comprises a cylindrical or conical first surface and a flat or conical second surface. The second surface is a radially outer surface. The first and second surfaces are connected. Radially outer means radially outward with respect to the axis of rotation of the workpiece, i.e. at a greater distance from the axis of rotation of the workpiece. The first and second surfaces are preferably connected by a concave surface. Preferably, the internal corner comprises a cylindrical first surface and a flat second surface. The first and second surfaces are connected by a concave surface. The second surface is a radially outer surface.

[0058] According to one embodiment, the entering angle and the angle the first cutting edge forms with respect to the axis of rotation of the workpiece varies during the non-linear portion of the non-linear first pass.

[0059] In other words, both of the respective angles vary during at least a portion of a non-linear portion, such as a curved segment of the non-linear first path.

[0060] In one embodiment, the method further comprises setting the maximum chip thickness to a constant, predetermined value or within a predetermined range during at least a portion of the first pass.

[0061] Such a turning method further improves tool life and / or chip control.

[0062] The results of such a method can be seen, for example, in a machined component where the distance between each of the feed marks, such as the leading edge, is shorter at or decreases towards the end of the pass.

[0063] Maximum chip thickness h x is also known as the undeformed chip thickness and is sometimes referred to as "hex". It is the maximum chip thickness measured perpendicular to the first chip-generating cutting edge when the second cutting edge becomes ineffective. When the second cutting edge becomes effective and the first cutting edge becomes ineffective, the maximum chip thickness is measured perpendicular to the second chip-generating cutting edge. In turning where the depth of cut exceeds the nose cutting edge with a constant entry angle and feed rate, the chip thickness h x is constant and defined as f × sinK, where f is the feed rate per revolution and K is the lead angle. For example, at a lead angle of 90°, the chip thickness, or maximum chip thickness, is equal to the feed rate. Even in this case, the lead angle may vary and the feed rate may vary along the first cutting edge.

[0064] When the cutting angle K changes, the maximum chip thickness h x is the maximum chip thickness measured along a line perpendicular to the first cutting edge.

[0065] When the cutting angle K varies, the distance that the surface generating point of the nose cutting edge moves per revolution can be specified as the feedrate per revolution. When the cutting angle K varies, the feedrate per revolution can be specified as the surface generating feedrate and can be defined as the distance that the surface generating point of the nose cutting edge moves per revolution of the metal workpiece.

[0066] "Substantially constant maximum chip thickness" means the maximum chip thickness h x varies within + / - 25% during at least 90% of the first and / or second passes. The leading edge angle K is defined as the angle between the feed direction generating the surface and the active main cutting edge, i.e. the first cutting edge or the second cutting edge. During the first pass, the first cutting edge is the active main cutting edge. During the second pass, the second cutting edge is the main cutting edge. The leading edge angle K is preferably equal to or less than 130°, preferably between 5° and 110°.

[0067] The predetermined value or the predetermined range may preferably be automatically selected from an electronic database or an electronic library. Preferably, the predetermined value or the predetermined range is equal to or substantially equal to a recommended feed value from the manufacturer of the cutting part, preferably taking into account the material of the metal workpiece.

[0068] Preferably, the maximum chip thickness h x is from 0.01 to 3 mm, more preferably from 0.03 to 2 mm, and even more preferably from 0.04 to 1.2 mm.

[0069] According to one embodiment, the first non-linear pass includes machining a bottom surface of the outer groove; The groove is defined by a first side wall, a second side wall, a bottom surface, a first corner surface, and a second corner surface. The first corner surface connects the bottom surface and the first side wall. The second corner surface connects the bottom surface and the second side wall. This method includes moving the nose cutting edge towards the first corner surface and increasing the rotational speed of the turning tool about its axis of rotation when a part of the turning tool, which is remote from the first cutting insert, reaches a predetermined distance from the first side wall.

[0070] The first non-linear path thus includes machining the bottom surface of the outer groove, preferably the first corner surface. The bottom surface is preferably a cylindrical surface concentric with the axis of rotation of the workpiece.

[0071] In other words, the first machined surface includes the bottom surface of the groove.

[0072] The groove, or pocket, is an outer groove. The groove preferably opens in a direction away from the axis of rotation of the workpiece. Alternatively, the groove opens in a direction parallel, or substantially parallel, to the axis of rotation of the workpiece.

[0073] The groove is defined by a first side wall, i.e., a first side wall surface, and a second side wall, i.e., a second side wall surface. Each of them is preferably perpendicular, or substantially perpendicular, to the axis of rotation of the workpiece. The first side wall faces the second side wall.

[0074] The groove is further defined by a first corner surface and a second corner surface. Each of the corner surfaces is a concave surface.

[0075] The method includes generating a portion of a first machined surface, i.e., at least a portion of the bottom surface, by moving a surface-generating nose cutting edge toward a first corner face, and increasing the speed of rotation of the turning tool about the tool's rotation axis when a portion of the turning tool that is inside the groove and away from the first cutting insert reaches a predetermined distance from the first sidewall, measured parallel to the workpiece rotation axis.

[0076] Increasing the speed of rotation of the turning tool about the tool's axis of rotation can alternatively be understood as increasing the rate at which the lead angle increases, in other words, the rate at which the lead angle increases is not constant when the portion of the turning tool reaches the predetermined distance from the first sidewall.

[0077] In other words, the portion of the turning tool reaches the predetermined distance from the first sidewall before the nose cutting edge that creates the surface.

[0078] The predetermined distance is preferably between 1 and 30 mm, and even more preferably between 2 and 15 mm.

[0079] The part of the turning tool is preferably either the front end of the tool body or a second cutting insert connected to the front end of the tool body.

[0080] In one embodiment, the method further comprises setting the chip area to be less than a predetermined value or within a predetermined range during at least a portion of the first pass.

[0081] Such a turning method may result in improved tool life.

[0082] The usual definition of chip area is the depth of cut (also known as cutting depth) times the feed per revolution. A revolution is relative to the workpiece. In other words, the chip area is the area of ​​material removed per revolution. More specifically, the feed per revolution is defined as the distance that the surface generating point of the nose cutting edge travels per revolution.

[0083] According to one embodiment, the method further comprises setting the maximum chip width to a predetermined value or within a predetermined range during at least a portion of the first pass.

[0084] Such a turning method may result in improved tool life.

[0085] The term setting a maximum chip width means selecting a predetermined point or area along the first cutting edge that will be active during the first pass. In other words, a portion of the first cutting edge will be inactive. The maximum chip width is preferably 12 mm or less, even more preferably 6 mm or less, even more preferably 3 mm or less. The maximum chip width is preferably 0.2 mm or more, more preferably 0.5 mm or more.

[0086] Preferably, the maximum width varies within + / - 40%, and even more preferably within + / - 20%, from the given value.

[0087] Alternatively, and more specifically, the method includes setting the cutting depth to be at a predetermined value or within a predetermined range.

[0088] According to one embodiment, the method includes making a second pass with the second cutting edge enabled and the first cutting edge disabled; The method further includes machining at least a portion of the first machined surface during a second pass, thereby producing a second machined surface with a convex nose cutting edge.

[0089] Such turning methods can reduce machining times, especially when machining pockets or grooves or the like that require deep removal of material.

[0090] Preferably, the direction of rotation of the metal workpiece about its axis of rotation is the same during both the first and second passes.

[0091] Preferably, the direction of the second pass is opposite, or substantially opposite, to the direction of the first pass.

[0092] According to one embodiment, the cutting portion is in the form of a cutting insert, The cutting insert includes an upper surface; In a top view, an angle between the first cutting edge and the second cutting edge is less than 90°; In top view, the convex nose cutting edge has a radius of curvature of 0.15 to 1.3 mm; The turning tool includes a tool body. The tool body includes a connection portion, an intermediate portion, and an insert seat; the intermediate section extends along a longitudinal central axis thereof; The cutting insert is placed on the insert seat, The tool body extends between the connecting portion and the front end of the tool body; The front end of the tool body includes an insert seat; The upper surface of the cutting insert faces away from the connecting portion, a central longitudinal axis of the connection defines an axis of rotation of the tool; The entering angle and the angle that the first cutting edge forms with respect to the axis of rotation of the workpiece changes during the first pass as a result of rotation of the turning tool about the tool's axis of rotation.

[0093] In such a way the risk of vibration is further reduced, since most of the cutting forces are directed towards the connection forces.

[0094] The angle between the first cutting edge and the second cutting edge is preferably between 10 and 80°, even more preferably between 10 and 65°, such turning tools allowing machining of more complex shapes than when the angle is greater than 80°.

[0095] In top view, the cutting insert is preferably completely inside the outer periphery of the connection portion.

[0096] In one embodiment, in a top view, the intermediate portion is at least 50% narrower along a bisector formed between the first and second cutting edges than along a line perpendicular to the bisector and intersecting the longitudinal central axis of the intermediate portion.

[0097] Stated differently, the front end of the tool body is at least 50% narrower along a bisector formed between the first and second cutting edges than along a line perpendicular to the bisector and intersecting the longitudinal central axis of the intermediate portion.

[0098] According to one embodiment, a computer program has instructions which, when executed by a computer numerically controlled lathe, cause the computer numerically controlled lathe to perform the method described above.

[0099] The computer program or computer program product therefore controls the tool path of the turning tool, the cutting data and the rotation of the metal workpiece.

[0100] With such a computer program, the turning method can be easily implemented on a number of CNC lathes or CNC machines.

[0101] The computer program has instructions for controlling the movement and rotation of the turning tool, and for rotating a metal workpiece and for moving the stock using a turning operation according to the method defined above.

[0102] The command may include cutting data such as cutting speed, feed rate, tool path, and depth of cut.

[0103] The computer program may be stored on a computer-readable medium.

[0104] A data stream may represent the computer program.

[0105] According to one aspect of the present invention, an automated, computer-executed method of generating a command for controlling a computer numerical control machine and creating features from a metal workpiece rotatable about its axis of rotation using any of the above turning tools, comprising: The method includes configuring a first pass according to any of the above first passes.

[0106] According to one aspect of the present invention, an automated, computer-executed method of generating a command for controlling a computer numerical control machine and creating features from a metal workpiece rotatable about its axis of rotation using a turning tool, comprising: The turning tool includes a cutting portion, the cutting portion includes a first nose portion, the first nose portion includes a first cutting edge, a second cutting edge, and a convex nose cutting edge connecting the first and second cutting edges, and the first and second cutting edges are straight or substantially straight in a top view. The method includes: Configuring a first pass such that the first cutting edge is effective, the second cutting edge is ineffective, the first machined surface is generated by the convex nose cutting edge, and the cutting angle and the angle formed by the first cutting edge with respect to the axis of rotation of the workpiece change simultaneously during at least a portion of the first pass.

[0107] Preferably, the tool path designer accesses a CAD drawing of the feature in a standard computer aided designing (CAD) format using an automated, computer implemented method that generates commands to control a computer numerically controlled machine. The tool path designer selects from a menu the turning tool to be used to create the feature. The tool path designer defines the properties of the turning tool, for example by collecting turning tool characteristics from an electronic tool library or by other means. The tool characteristics include the turning tool geometry or outer boundary and the recommended cutting data. For simplicity, the features shown here are chosen to be features such as outer grooves that can be created by a single machining function. It is noted that the applicability of the present invention is not limited to features that can be created by a single machining function.

[0108] The tool path designer then defines the geometry of the metal workpiece to be used to create the feature. This may be done automatically by an automated, computer implemented machine of the present invention, or manually by the tool path designer. The tool path designer then specifies the specific metal material of the metal workpiece. A set of machining steps or passes may be calculated recursively, whereby preferably a first pass is initially calculated for an initial area of ​​the workpiece. A subsequent second pass is then similarly calculated for the remaining area of ​​the workpiece. The first and second passes are preferably non-linear. Further subsequent, successive machining steps or passes may be similarly calculated until a tool path is calculated that machines the desired feature.

[0109] An automated, computer-implemented method may preferably be used for computer-aided manufacturing. The method preferably takes into account constraints such as feature geometry and turning tool geometry. The method preferably includes constraints that minimize the risk of collision between the metal workpiece and the turning tool. The automated, computer-implemented method may preferably be used for any of the above turning method embodiments or parts thereof.

[0110] The automated, computer-implemented method preferably further includes simultaneously increasing the lead angle and decreasing the surface-generating feed rate during at least a portion of the first pass.

[0111] According to one embodiment, the automated computer-implemented method further includes setting the maximum chip thickness to a constant, predetermined value or within a predetermined range during at least a portion of the first pass.

[0112] Preferably, said value or range of maximum chip thickness is selected from an electronic tool library or an electronic machining database, which preferably includes materials and geometries of cutting parts (preferably in the form of cutting inserts) and recommended cutting data for such cutting parts for at least one specific type of metal. The maximum chip thickness is in other words selected as a result of at least the material of the metal workpiece and / or the material and / or geometry of the cutting part.

[0113] The tool path designer preferably sets a first cut angle associated with a first point of the first pass and a second cut angle associated with a second point of the first pass, whereby the automated, computer-implemented method preferably further comprises calculating a feed rate, a surface-generating feed rate, for the first and second points according to the formula f=max chip thickness / sin K, and linearly interpolating the feed rate (or surface-generating feed rate) and cut angle for each point along the machined surface between the first and second points.

[0114] According to one embodiment, the feature is in the form of an exterior groove defined by a bottom surface, first and second side walls, and first and second corner surfaces; a first corner surface connecting the bottom surface and the first sidewall; a second corner surface connecting the bottom surface and the second sidewall; The first pass includes machining a bottom surface and a second corner surface; The method includes setting a corner inlet angle, a corner exit inlet angle, and a longitudinal exit inlet angle; Further including providing a stepless or gradual change in cut angle between the corner cut angle and the corner exit cut angle, and between the corner cut angle and the longitudinal exit cut angle.

[0115] The bottom surface is preferably a cylindrical surface concentric with the axis of rotation of the metal workpiece. The first and second side walls are preferably flat or substantially flat and perpendicular to the axis of rotation of the metal workpiece. The first and second corner surfaces are preferably curved, preferably having a constant radius of curvature.

[0116] The first pass is non-linear and includes machining the bottom surface and the second corner surface, and preferably also includes machining the first corner surface.

[0117] The non-linear first pass includes machining the second corner surface in a curved direction toward the axis of rotation and toward the base surface, and subsequently machining the base surface in a direction away from the second corner surface.

[0118] The corner inlet angle is the inlet angle at the beginning or entry of machining the second corner face. The corner exit inlet angle is the inlet angle at the end or exit of the second corner face. The corner exit inlet angle is equal to the longitudinal inlet angle. The longitudinal exit inlet angle is the inlet angle at the beginning or entry of machining the bottom face.

[0119] Preferably, the corner inlet angle is greater than the corner outlet angle.

[0120] Preferably, the longitudinal exit cut angle is greater than the corner exit cut angle.

[0121] Preferably, the corner cut angle is set between 60 and 120°, even more preferably between 80 and 110°.

[0122] Preferably, the corner exit cut angle is set at 20 to 80°, even more preferably at 25 to 45°.

[0123] Preferably, the longitudinal exit cut angle is set to between 60 and 120°, even more preferably between 80 and 110°.

[0124] Preferably, the non-linear first pass includes machining a first corner face, which occurs immediately after machining the bottom face.

[0125] The leading edge angle at the beginning or entry of machining the first corner face is equal to the longitudinal exit leading edge angle.

[0126] The cutting angle at the end or exit of the first corner face is K 6and is preferably set to between 10 and 80°, and even more preferably between 25 and 45°.

[0127] The nonlinear first pass may be such that the nose cutting edge begins cutting before the second corner face. In such a case, the entry cutting angle is 1 It is specified as follows.

[0128] All cutting angles are defined as the angle between the first cutting edge and the feed direction that creates the surface.

[0129] The first cutting edge is active during at least machining the bottom surface. If the first cutting edge is inactive during a portion of the non-linear first pass, the lead angle may still be defined according to the above definition.

[0130] The lead angle K is preferably varied continuously, i.e., without steps, during at least a portion of the non-linear first pass. Alternatively, the lead angle K is varied gradually, preferably by less than 2°. The CNC lathe sets limits on the variation of the lead angle.

[0131] Preferably, the automated computer-implemented method includes a second non-linear pass, where the first corner face is machined before the bottom face, and the bottom face is machined before the second corner face.

[0132] In other words, the nonlinear second path is generally in the opposite direction to the nonlinear first path.

[0133] During the second non-linear pass, each of the cut angles is preferably selected correspondingly with respect to the non-linear first pass.

[0134] Preferably, the automated, computer-implemented method includes a sequence of alternating non-linear paths.

[0135] According to one aspect, a turning tool includes a tool body and a cutting portion, the cutting portion including a first cutting insert and a second cutting insert; the tool body includes a connection portion, a middle portion, a first insert seat for the first cutting insert, and a second insert seat for the second cutting insert; The tool body extends between the connecting portion and the front end of the tool body; The front end of the tool body includes a first insert seat and a second insert seat; the first cutting insert includes a bottom surface opposite the top surface, a side surface connecting the top surface and the bottom surface; an intermediate surface extending intermediately between the top surface and the bottom surface; an upper surface of the first cutting insert facing away from the connecting portion; the second cutting insert includes a bottom surface opposite the top surface, a side surface connecting the top surface and the bottom surface; an intermediate surface extending intermediately between the top surface and the bottom surface; an upper surface of the second cutting insert facing away from the connecting portion; a central longitudinal axis of the connection defines an axis of rotation of the tool; the intermediate section extends along a longitudinal central axis thereof; in a top view, a maximum distance between the first and second cutting inserts is greater than a width of a front end of the tool body, the width of the front end of the tool body being measured perpendicular to the maximum distance between the first and second cutting inserts; The length of the intermediate portion, measured along the longitudinal central axis, is greater than the maximum distance between the first and second cutting inserts.

[0136] Such turning tools may further improve machine utilization: complex shapes can be machined more efficiently with such turning tools.

[0137] The turning tool is suitable for use in the turning method defined above.The first and second cutting inserts are preferably made from a wear-resistant material suitable for metal cutting, such as cemented carbide.

[0138] The connecting section and intermediate section are preferably made from a single piece of steel, are preferably permanently connected and together form the tool body.

[0139] The tool body extends between a connection portion that is adapted to be connected directly or indirectly to a machining interface of a CNC lathe, and a front end facing away from the connection portion.

[0140] The front end of the tool body includes a first insert seat for the first cutting insert and a second insert seat for the second cutting insert.

[0141] The first cutting insert includes a bottom surface positioned to function as a seat surface and an opposing top surface positioned to include a rake surface. The top surface of the first cutting insert faces away from the connecting portion.

[0142] The top surface preferably comprises chip breaking means, preferably in the form of one or more protrusions and / or recesses. The bottom surface preferably comprises anti-rotation means, preferably in the form of one or more protrusions and / or recesses, for cooperation with anti-rotation means in the first insert seat. Alternatively, the bottom surface may be devoid of anti-rotation means. For example, the bottom surface may be flat or substantially flat. In such a case, the side surface connecting the top surface and the bottom surface functions as a seat or contact surface. That is, the side surface contacts the surface of the first insert seat.

[0143] One or more cutting edges are formed at the intersection between the top surface and the side surfaces. In top view, the top surface may have any shape.

[0144] Each of the first and second cutting inserts may include a first and second cutting edge connected by a respective nose cutting edge. In a top view, the front end of the tool body is inside a line coinciding with each of the first and second cutting edges of the first and second cutting inserts. Such turning tools allow for machining of more complex shapes.

[0145] The first cutting insert includes a cutting edge that is arranged to be a cutting edge generating surface that, in top view, is convexly curved, for example in the form of an arc or circle having a radius of curvature preferably between 0.15 and 30 mm, even more preferably between 0.3 and 25 mm.

[0146] The intermediate surface extends intermediately between the top surface and the bottom surface and is preferably disposed perpendicular or substantially perpendicular to the longitudinal central axis of the intermediate portion.

[0147] Preferably, holes for the clamping screws, i.e. through holes, are preferably open at the top and bottom faces.

[0148] The second cutting insert may be disposed, i.e., formed, corresponding to the first cutting insert. Alternatively, the second cutting insert may have a shape different from the shape of the first cutting insert. The top surface of the second cutting insert faces away from the connection portion.

[0149] In top view, the first and second cutting inserts for cutting are preferably completely inside the outer circumferential surface of the connection part.

[0150] The second cutting insert is located in the second insert seat.

[0151] The first and second cutting inserts are removably clamped or mounted to respective insert seats by clamping means, preferably in the form of clamping screws.

[0152] The first and second insert seats are spaced apart and preferably located on opposite sides of the longitudinal central axis of the intermediate portion. Each of the first and second cutting inserts forms a free end of the turning tool. In other words, each of the first and second cutting inserts includes a convex cutting edge that creates a surface that forms the free end of the turning tool.

[0153] The intermediate surface of the second cutting insert extends intermediately between the top and bottom surfaces of the second cutting insert and is preferably coplanar with the corresponding intermediate surface of the first cutting insert.

[0154] The central longitudinal axis of the connecting portion defines the axis of rotation of the tool and is preferably collinear with, or alternatively parallel to, the central longitudinal axis of the intermediate portion.

[0155] In a top view, the maximum distance between the first and second cutting inserts, more specifically, the portions of the first and second cutting inserts positioned to function as surface generating portions or cutting edges, respectively, is longer than the width of the front end of the tool body, which width is measured perpendicular to the maximum distance between the first and second cutting inserts.

[0156] In other words, the front end and the middle portion are elongated when viewed in a front view.

[0157] The intermediate portion has a length or distance along the longitudinal central axis, and the cross-section of the intermediate portion is preferably uniform or substantially uniform for at least 50%, and even more preferably at least 70%, of that distance from the forward end of the tool body.

[0158] The length or distance of the intermediate portion is longer than the maximum distance between the first and second cutting inserts, and even more preferably is 50 to 300% longer.

[0159] The invention will be described in more detail below with reference to various embodiments of the invention and the accompanying drawings. [Brief description of the drawings]

[0160] [Figure 1] FIG. 1 is a perspective view of a tool body that is part of a first turning tool. [Diagram 2] FIG. 2 is a perspective view of a first turning tool. [Diagram 3]FIG. 3 is a perspective view of an insert seat of the tool body of FIG. [Figure 4] FIG. 4 is a side view of the turning tool of FIG. [Diagram 5] FIG. 5 is a further side view of the turning tool of FIG. [Figure 6] FIG. 6 is a side view of the second turning tool. [Figure 7] FIG. 7 is a perspective view of the turning tool of FIG. [Figure 8] FIG. 8 is a top view of the turning tool of FIG. [Figure 9] FIG. 9 is a perspective view of a third turning tool. [Figure 10] FIG. 10 is a side view of the turning tool of FIG. [Figure 11] FIG. 11 is a perspective view of the tool body of FIG. [Figure 12] 12 is a perspective view of an insert seat of the tool body of FIG. 11. FIG. [Figure 13] FIG. 13 is a perspective view of the cutting insert of FIG. [Figure 14] FIG. 14 is a side view of the cutting insert of FIG. [Figure 15] FIG. 15 is a top view of the cutting insert of FIG. [Figure 16] FIG. 16 is a further perspective view of the cutting insert of FIG. [Figure 17] FIG. 17 is a side view of the fourth turning tool. [Figure 18] FIG. 18 is a further side view of the turning tool of FIG. [Figure 19] FIG. 19 is a perspective view of the turning tool of FIG. [Figure 20] FIG. 20 is a top view of the turning tool of FIG. [Figure 21] FIG. 21 is a side view of a first turning method using the turning tool of FIG. [Figure 22] FIG. 22 is a side view of a modification of the first turning method using the turning tool of FIG. [Diagram 23] FIG. 23 is a second side view of FIG. [Figure 24] FIG. 24 is a perspective view of the turning tool and metal workpiece shown in FIG. [Diagram 25] FIG. 25 is a side view of a second turning method using the turning tool of FIG. [Figure 26] FIG. 26 is a further side view of a second turning method using the turning tool of FIG. [Figure 27] FIG. 27 is a side view of a third turning method using the turning tool of FIG. [Figure 28-37] 28 to 37 are diagrams of a fourth turning method. [Figure 38] FIG. 38 shows a combination of FIG. 29 and FIG. [Figure 39] FIG. 39 is an enlarged view of a portion of FIG. [Figure 40-49] 40 to 49 are diagrams of a fifth turning method. [Figure 50] FIG. 50 shows a sixth turning method. [Figure 51] FIG. 51 shows the seventh turning method. [Figure 52] FIG. 52 shows an eighth turning method using a fifth turning tool. [Figure 53-58] 53 to 58 are diagrams of a ninth turning method using a fifth turning tool. [Figure 59] FIG. 59 is a perspective view of a fifth turning tool. [Figure 60] FIG. 60 is a side view of the turning tool shown in FIG. [Figure 61] FIG. 61 is a further side view of the turning tool shown in FIG. [Figure 62] FIG. 62 is a top view of the turning tool shown in FIG.

[0161] All turning tool and cutting insert drawings are drawn to scale. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0162] The invention is described in more detail below. Furthermore, examples of turning tools that can be used to perform the method according to the invention are described. Five turning tools are described in more detail. Such turning tools have been found to be particularly suitable for performing the above turning methods. Nine turning methods are described, some of which are general and some of which are more detailed. All described turning tools can be used in any of the described turning methods.

[0163] Reference is made to figures 1 to 5. They show a first turning tool 1 comprising a tool body 3 and a first cutting insert 2. The tool body 3 without the cutting insert 2 is shown in figure 1. The turning tool comprises an insert seat 6 shown in figure 3. The turning tool 1 is a turning tool comprising a connecting part 4, an intermediate part 5 and a cutting part 2. The connecting part 4 and the intermediate part 5 are permanently connected and jointly form the tool body 3 made of steel. The first cutting insert 2 is made of sintered carbide. The first turning tool 1 comprises only one cutting insert. The connecting part 4 is suitable for connection to a rotatable machining interface (not shown), such as a machine spindle. The connecting part 4 comprises a substantially conical or tapered part 39 and a ring-shaped part 40 according to ISO26623-1:2014. Alternatively, other quick-form connections may be used.

[0164] The front end 20 or forward end of the tool body 3 is defined by a first insert seat 6 for the first cutting insert 2. The first cutting insert 2 is releasably clamped to the first insert seat 6 by clamping means 14, which is in the form of a clamping screw 14.

[0165] The first cutting insert 2 includes a bottom surface 8 opposite a top surface 7. A side surface 9 connects the top and bottom surfaces 7 and 8.

[0166] As can be seen in FIG. 4, intermediate surface M1 extends midway between top and bottom surfaces 7 and 8.

[0167] The intermediate portion 5 extends between the connecting portion 4 and the cutting portion 2 .

[0168] The central longitudinal axis of the connection part 4 defines the rotation axis R1 of the tool.

[0169] The intermediate portion 5 extends along its central longitudinal axis A1.

[0170] For the first turning tool 1, the longitudinal centre axis A1 is collinear or coaxial with the tool's axis of rotation R1, as can be seen in Figures 2, 4 and 5.

[0171] The intermediate plane M1 is perpendicular to the longitudinal central axis A1 of the intermediate portion 5 and perpendicular to the rotation axis R1.

[0172] An upper surface 7 of the first cutting insert 2 faces away from the connecting portion 4. The upper surface 7 is non-planar and includes a chip breaking means or chip breaker in the form of a protrusion.

[0173] The first cutting insert 2 comprises first and second nose portions 10 and 10 ′, respectively, which form the free end of the turning tool 1 .

[0174] The first nose portion 10 includes a first cutting edge 11, a second cutting edge 12, both of which are straight in top view, and a convex nose cutting edge 13 connecting the first and second cutting edges 11 and 12. The convex nose cutting edge 13 is convex in top view. The nose cutting edge 13 is convexly curved in top view and has a radius of curvature of 0.15 to 1.3 mm. Although not shown in the top view of the turning tool according to the first embodiment, a top view of the first cutting insert 2 according to the first embodiment is shown in FIG. 8 showing the same cutting insert.

[0175] According to a first embodiment, the radius of curvature is 0.4 mm.

[0176] The first and second cutting edges 11 and 12 form a nose angle that is 35°.

[0177] In top view, the first and second nose portions 10 and 10' form an angle of 180° relative to each other, measured about the central longitudinal axis A1 of the intermediate portion 5.

[0178] The first cutting insert 2 is symmetrical by 180° in the top and bottom views. The first cutting insert is a parallelogram in the top view.

[0179] 3, the first insert sheet 6 includes a first insert sheet rotation locking means including ridges 23 to 26. The two ridges 23 and 26 are collinear and the two ridges 24 and 25 are parallel.

[0180] The first cutting insert 2 includes first cutting insert rotational locking means in the form of grooves (not shown) formed in the bottom surface 8 which cooperate with the first insert seat rotational locking means 23 to 26 .

[0181] The first cutting insert 2 includes a hole for a clamping screw 14. The hole 13 intersects the top and bottom faces 8 and 9. Its central axis defines a central axis of the first cutting insert that is collinear with the rotational axis R1 and the longitudinal central axis A1.

[0182] The turning tool 1 includes a coolant channel formed in the tool body 3 and extending between the connection portion 4 and a nozzle 28 formed in the intermediate portion 5. The coolant channel and nozzle 28 are positioned to direct coolant fluid towards the first and second nose portions 10 and 10'.

[0183] Reference is now made to Figures 9 to 16, which show a third turning tool 1 comprising a first cutting insert 2. The main difference compared to the first turning tool concerns the design of the first cutting insert 2 and the insert seat 6.

[0184] 15, a first extension line 21 collinear with the first cutting edge 11 and a second extension line 22 collinear with the second cutting edge 12 extend on opposite sides with respect to a central axis A2 of the first cutting insert, which is collinear with the rotation axis R1 and the longitudinal central axis A1 when the cutting insert 2 is placed in the insert seat 6. The previous sentence also applies to the turning tool 1 according to the first embodiment.

[0185] The first cutting insert 2 includes three nose portions 10, 10', and 10''. The first cutting insert 2 is 120° symmetrical in top and bottom views.

[0186] In a top view as seen in FIG. 15, the first and second cutting edges 11 and 12 form a nose angle α that is 35°.

[0187] 12, the first insert seat 6 includes a first insert seat rotation locking means including ridges 23 to 25. The ridges 23 to 25 extend radially relative to the holes 32 formed in the first insert seat 6 for the clamping screws 14.

[0188] The first cutting insert 2 includes first cutting insert rotational locking means, which include grooves 16-18 formed in the bottom surface 8 and which cooperate with first insert seat rotational locking means 23-26.

[0189] Reference is now made to Figures 17 to 20, which show a fourth turning tool 1. The fourth turning tool 1 differs from the first turning tool mainly in that the turning tool 1 comprises second and third cutting inserts 29 and 30 clamped or mounted on second and third insert seats, respectively, which are formed in the intermediate part 5 of the tool body 3, longitudinally between and spaced apart from the first cutting insert 2 and the connecting part 4.

[0190] Each of the second cutting insert 29 and the third cutting insert 30 differs in shape in top view compared to the first cutting insert 2. The third cutting insert 30 is a threading insert.

[0191] Each of the second and third cutting inserts 29 and 30 includes a nose portion, each of the nose portions including a set of cutting edges.

[0192] Compared to the first cutting insert 2 , the second and third cutting inserts 29 and 30 are located at a greater distance from the longitudinal central axis A1 of the intermediate portion 5 .

[0193] In a top view as seen in FIG. 20, the second and third cutting inserts 29 and 30 each form an equally large angle or a substantially equally large angle with respect to the first and second nose portions. In FIG. 20, the first cutting insert includes two nose portions 10 and 10' located at 6 o'clock and 12 o'clock, respectively. The second cutting insert 29 is located at 9 o'clock and the third cutting insert 30 is located at 9 o'clock. The time references refer to the time on an analog 12-hour watch and relate to the relative positions with respect to the longitudinal central axis A1. With such a turning tool, the clearance is further improved.

[0194] As can be seen in FIG. 17, the second and third cutting inserts 29 and 30 are located at equal or substantially equal distances from the clamping portion 4 in the longitudinal direction.

[0195] Here, refer to FIGS. 6 to 8. These show the second turning tool 1. The second turning tool 1 mainly has the following features regarding the second turning tool 1: the longitudinal central axis A1 is parallel to the tool rotation axis R1 and is away from this axis, and the convex nose cutting edge 13 of the first nose portion 10 intersects or substantially intersects the tool rotation axis R1. In other words, the intermediate portion 5 is offset with respect to the tool rotation axis R1. The midpoint of the convex nose cutting edge 13 of the first nose portion 10 is located at 0.5 mm or less from the tool rotation axis R1.

[0196] In other embodiments, the second turning tool 1 is the same as or similar to the first turning tool. For example, in a top view as shown in FIG. 8, the first extension line 21 collinear with the first cutting edge 11 and the second extension line 22 collinear with the second cutting edge 12 extend on the opposite sides with respect to the longitudinal central axis A1 of the intermediate portion 5.

[0197] According to the first, third, and fourth embodiments, in a top view as shown in FIG. 8, the intermediate portion 5 and the first cutting insert 2 are inside the outer boundary line of the connection portion 4.

[0198] Here, pay attention to FIG. 21. This shows, in a side view, the relative positions and orientations of the metal workpiece 31 and the third turning tool 1 when performing the first turning method. Alternatively, any of the other above-mentioned turning tools can be used. The turning tool 1 includes a connection portion 4 clamped to a machining interface 40 of a CNC lathe (not shown), an intermediate portion 5, and a cutting portion 2 in the form of a cutting insert. The CNC lathe (not shown) can be commanded to perform the turning method by instructions in a computer program, a computer-readable medium, or a data stream. The longitudinal central axis of the connection portion 4 defines the tool rotation axis R1. The intermediate portion 5 extends along its longitudinal central axis A1. The cutting portion 2 includes an opposing upper surface away from the connection portion 4.

[0199] The metal workpiece 31 rotates clockwise in FIG. 21 about the workpiece's axis of rotation R2.

[0200] The tool rotation axis R1 is perpendicular to the workpiece rotation axis R2. The tool rotation axis R1 is arranged such that a tangent to the metal workpiece 31 at the contact point with the convex nose cutting edge 13 intersects with the connection 4. The cutting force at the tangent is directed towards the machining interface 40. The tool rotation axis R1 is an arbitrary distance away from the circumferential surface of the metal workpiece 31. The tool rotation axis R1 is parallel to the tangent.

[0201] Attention is now drawn to Figure 22, which shows the relative positions and orientations of the metal workpiece 31 and the third turning tool 1 when performing an alternative to the first turning method. The arrangement of Figure 22 differs from that of Figure 21 only in that the axis of rotation R1 of the tool is not parallel to the tangent line, but forms an angle of less than 10° with respect to the tangent line.

[0202] Attention is now directed to FIG. 23, which shows a side view of the center position of the cutting insert 2 comprising the turning tool 1 during machining of a predetermined feature in the form of an external pocket or groove 52. Machining the external groove 52 comprises a non-linear, i.e. curvilinear, first pass, in which the first cutting edge is active and the second cutting edge is inactive, such that the first machined surface is generated by a convex nose cutting edge, and during at least a portion of the first pass, the leading edge angle and the angle that the first cutting edge forms with respect to the rotation axis R2 of the workpiece are simultaneously changed. Machining the external groove comprises a non-linear, i.e. curvilinear, second pass, in which the second cutting edge is active and the first cutting edge is inactive, such that at least a portion of the first machined surface is machined during the second pass, thereby generating the second machined surface by the convex nose cutting edge. In FIG. 23, the first path is generally to the left and the second path is generally to the right.

[0203] Attention is now directed to Figure 24, which shows a perspective view of the arrangement shown in Figure 21. The metal workpiece 31 shown therein is cylindrical and includes a lateral surface 31, i.e. the surface facing away from the workpiece's axis of rotation R2, and a base surface 42, i.e. the surface facing in a direction parallel to the workpiece's axis of rotation R2. The metal workpiece 31 includes a second base surface facing away from the viewer. In the first turning method described above, machining is performed on the lateral surface 41 of the metal workpiece 31. In a third turning method shown in Figure 27, machining is performed on the base surface 42 of the metal workpiece 31.

[0204] Attention is now directed to Figures 25 and 26, which show a second turning method using a fourth turning tool 1. The method includes using a first cutting insert 2, where the fourth turning tool 1 is in a position relative to a metal workpiece 31 as shown in Figure 25. The second turning method includes machining using the first turning insert 2 according to any of the turning methods described above or below. The second turning method further includes moving the turning tool 1 away from the metal workpiece 31 and moving the turning tool 1 forward along the tool rotation axis R1 to the position shown in Figure 26. The method further includes rotating the turning tool 1 about the tool rotation axis R1 through a predetermined angle such that the second cutting insert 29 is in an effective position. The predetermined angle is in the range of 80° to 100°.

[0205] Reference is now made to Figure 27. This shows a turning method using a second turning tool 1. However, any of the turning tools described above or below may be used. A metal workpiece 31 is provided. It rotates about the workpiece's axis of rotation R2. The tool's axis of rotation R1 is perpendicular to the workpiece's axis of rotation R2. A machining or turning method is performed on the base or end face of the metal workpiece 31.

[0206] The tool rotation axis R1 is perpendicular to the workpiece rotation axis R2. In this example, both the workpiece rotation axis R2 and the tool rotation axis R1 are in a horizontal position. One possible alternative is to place both the workpiece rotation axis R2 and the tool rotation axis R1 in a vertical position.

[0207] The cutting insert 2 includes first and second nose portions 10 and 10'. In the method of Fig. 27, the second nose portion 10' is in the effective position. The method can alternatively be performed such that the first nose portion 10 is in the effective position. In such a case, the turning tool 1 is rotated 180° about the tool rotation axis R1.

[0208] The method includes making a first pass 36 by moving the turning tool such that the first cutting edge 11' is active, the second cutting edge 12' is inactive, and the machined surface is formed by the nose cutting edge 13'.

[0209] The method includes making a second pass 37 by moving the turning tool such that the first cutting edge 11' is inactive and the second cutting edge 12' is active such that at least a portion of the machined surface from the first pass 37 is machined.

[0210] During the first pass, the turning tool rotates in a first direction, which is counterclockwise in FIG. 34, about the tool's axis of rotation R1.

[0211] During a second pass 37, the turning tool rotates about its axis of rotation in a second direction, here clockwise in Fig. 27, which is opposite to the first direction.

[0212] During the first pass 36, the turning tool is moved along a non-linear or curvilinear path. The first pass includes a radial component 34, which is perpendicular to and directed towards the workpiece axis of rotation R2, downward in FIG.

[0213] During the second pass 37, the turning tool is moved along a non-linear or curved path. The second pass includes a radial component 35 that is perpendicular to and away from the workpiece axis of rotation R2 and upwards in FIG. 27, i.e., in the opposite direction to the radial component 34 of the first pass.

[0214] During at least a portion of each of the first and second passes 36 and 37, the lead angle and the angle that the first cutting edge forms with respect to the axis of rotation R2 of the workpiece are simultaneously varied.

[0215] After the first pass 36 and before the second pass 37 , the turning tool is withdrawn from the metal workpiece 31 .

[0216] Attention is now directed to figures 28 to 37. A cutting part 2 in the form of a cutting insert 2 is shown. The remaining parts of the turning tool are not shown. Turning tools described as first, second, fourth or fifth turning tools may be used. Figures 28 to 37 show a sequence or steps of a turning method. Together they form a first pass. The figures are in chronological order. The cutting insert 2 is moved in figures 28 to 31 upwards in these figures, i.e. towards the axis of rotation R2 of the workpiece. This is a radial movement. The cutting insert 2 is moved in figures 33 to 37 to the right, i.e. substantially parallel to the axis of rotation R2 of the workpiece. This is a longitudinal movement. Figure 32 shows the end of the radial movement and the beginning of the longitudinal movement. This machining sequence shows a non-linear first pass. Here a first machined surface 38 is generated by a convex nose cutting edge 13. Here, the first cutting edge 11 is effective. The axis of rotation of the tool (not shown) is pointed or oriented towards the viewer, in other words, perpendicular or substantially perpendicular to the axis of rotation R2 of the workpiece.

[0217] During at least a portion of the first pass, the leading edge angle K and the angle β that the first cutting edge forms with respect to the axis of rotation R2 of the workpiece are simultaneously changed.

[0218] FIG. 38 shows both FIG. 29 and FIG. 30. Here, FIG. 30 shows the position of the turning insert 2 after the metal workpiece has been rotated one revolution about its axis of rotation from the turning insert 2 in the position of FIG. 29. It can be seen that the cutting angle increases as the surface generating nose cutting edge 13 of the turning insert 2 is moved forward. Between FIG. 29 and FIG. 30, the movement of the surface generating point 56 of the nose cutting edge 13 is linear, towards the axis of rotation R2. The surface generating feed rate (per revolution) is, at least approximately, the distance between each of the surface generating points 56 of the nose cutting edge 13 of FIG. 29 and FIG. 30.

[0219] Figure 39 shows a section of Figure 38. The chip area 44 represents the area of ​​material removed per revolution. The chip area 44 can be understood, at least in theory, as the cross-section of the chip removed during the turning process. As can be seen, the chip area 44 is not uniform.

[0220] When the cutting angle K changes, the maximum chip thickness h x is the maximum chip thickness measured along a line perpendicular to the first cutting edge 11.

[0221] When the cutting angle K varies, the distance that the surface generating point 56 of the nose cutting edge 13 moves per revolution can be specified as the feedrate per revolution. When the cutting angle K varies, the feedrate per revolution can be specified as the surface generating feedrate and can be defined as the distance that the surface generating point 56 of the nose cutting edge moves per revolution of the metal workpiece.

[0222] The maximum chip thickness 43 is preferably set to a constant, predetermined value or within a predetermined range during at least a portion of the first pass 36 .

[0223] Attention is now directed to figures 40 to 49. A cutting part 2 in the form of a cutting insert 2 is shown. The remaining parts of the turning tool are not shown. Turning tools described as first, second, fourth or fifth turning tools may be used. Figures 28 to 37 show a sequence or steps of the turning method, which together form a first pass. The figures are in chronological order. The cutting insert 2 is moved in figures 40 to 41 and 48 to 49 to the right in these figures, i.e. substantially parallel to the axis of rotation R2 of the workpiece. This is a longitudinal movement. Figures 40 to 41 show a first longitudinal movement. Figures 48 to 49 show a second longitudinal movement, with a diameter smaller than that of the first longitudinal movement. Figures 42 to 48 show a profiling movement. Here, the cutting insert is moved towards the workpiece's axis of rotation R2, towards the right in these figures, at an angle relative to the workpiece's axis of rotation R2. Figure 48 shows the end position of the cutting insert 2 in the profiling movement, which is also the start position of the cutting insert 2 in the second longitudinal movement.

[0224] During at least a portion of the first pass, the leading edge angle K and the angle β that the first cutting edge forms with respect to the axis of rotation R2 of the workpiece are simultaneously changed.

[0225] Attention is now directed to FIG. 50. A fifth turning tool 1 is shown. The turning tool 1 comprises a first cutting insert 2, a second cutting insert 3 and a tool body 3. The tool body 3 comprises a connection part 4, an intermediate part 5 and an insert seat. The first and second cutting inserts are placed on the insert seat. The longitudinal central axis of the connection part 4 defines a tool rotation axis R1. About the tool rotation axis R1 the turning tool 1 is rotatable. The respective top faces of the first and second cutting inserts 2 and 45 face away from the connection part 4. The metal workpiece 31 is rotatable about the workpiece rotation axis R2. The tool rotation axis R1 is perpendicular to the workpiece rotation axis R2. The turning tool 1 is used for machining a predetermined feature in the form of an outer groove 52. The outer groove 52 opens in a direction away from the workpiece rotation axis R2. The groove 52 is defined by a first sidewall 48, a second sidewall 49, a bottom surface 47, a first corner surface 50 and a second corner surface 51. The first corner surface 50 connects the bottom surface 47 and the first sidewall 48. The second corner surface 51 connects the bottom surface 47 and the second sidewall 49. Machining the groove 52 comprises a sequence of non-linear passes. The sequence of machined surfaces is generated by the nose cutting edge 13 of the first cutting insert 2. The passes of the machining sequence comprise alternatively machining in substantially opposite longitudinal directions, in other words alternatively towards substantially the right side, where the first cutting edge 11 is active, and alternatively towards the left side, where the second cutting edge 12 is active.

[0226] The machining sequence includes a first nonlinear pass 36, in which a first machined surface 38 is generated by the convex nose cutting edge 13. Here, the first cutting edge 11 is active. The first nonlinear pass 36 is followed by a second nonlinear pass 37, in which a second machined surface 39 is generated by the nose cutting edge 13. Here, the second cutting edge 12 is active.

[0227] Attention is now directed to FIG. 51. The outer groove 52 is machined by a turning tool (not shown) including a first cutting insert 2. A turning tool described as a first, second, fourth, or fifth turning tool may be used. A number of positions of the first cutting insert 2 during a non-linear first pass are shown. Here, the first cutting insert is moved towards the right. The groove 52 is defined by a first sidewall 48, a second sidewall 49, a bottom surface 47, a first corner surface 50, and a second corner surface 51. The first corner surface 50 connects the bottom surface 47 and the first sidewall 48. The second corner surface 51 connects the bottom surface 47 and the second sidewall 49. The bottom surface 47 is a cylindrical surface concentric with the rotation axis R2 of the workpiece.

[0228] During the non-linear first pass, the first cutting edge 11 is active and the second cutting edge 12 is inactive. A first machined surface 38 is generated by the convex nose cutting edge 13. During at least a portion of the first pass 36, the cutting angle K and the angle β that the first cutting edge 11 forms with respect to the workpiece rotation axis R2 change simultaneously.

[0229] The turning method is as follows: 2 and the exit cut angle K of the second corner surface 51. 3 and the vertical exit cut angle K of the bottom surface 47 5 and the cutting angle K at the exit of the first corner surface 50. 6 and setting

[0230] The non-linear first pass may be such that the nose cutting edge 13 and / or the first cutting edge 11 begin cutting before the second corner face 51. In such a case, the entry cutting angle is K 1 (not shown). Similarly, the non-linear first pass may be such that the nose cutting edge 13 and / or the first cutting edge 11 finish cutting after the first corner face 50.

[0231] Corner cutting angle K 2is the corner exit cutting angle K 3 Larger. Longitudinal exit cutting angle K 5 is the corner exit cutting angle K 3 Greater than.

[0232] Corner cutting angle K 2 is set to 60 to 120°, and even more preferably 80 to 110°. 3 is set to 20 to 80°, and even more preferably to 25 to 45°. 5 is set to between 60 and 120°, and even more preferably between 80 and 110°.

[0233] K 6 is preferably set at 10 to 80°, even more preferably at 25 to 45°.

[0234] During the first nonlinear pass, the cutting angle K is preferably changed continuously, i.e., without steps, during at least a portion of the nonlinear first pass. Alternatively, the cutting angle K is changed gradually, preferably by less than 2°.

[0235] Rotation of the turning tool about the tool's axis of rotation during the first nonlinear pass is in one direction only, i.e., clockwise when viewed as in FIG. 51 with the connection facing away from the viewer.

[0236] Attention is now directed to FIG. 52. The outer groove 52 is machined by a fifth turning tool 1, which includes the first cutting insert 2 and the second cutting insert 45. Several positions of the first turning tool 1 are shown during a non-linear first pass, where the turning tool 1 is moved towards the right. The groove 52 is defined by a first sidewall 48, a second sidewall 49, a bottom surface 47, a first corner surface 50 and a second corner surface 51. The first corner surface 50 connects the bottom surface 47 and the first sidewall 48. The second corner surface 51 connects the bottom surface 47 and the second sidewall 49. The bottom surface 47 is a cylindrical surface, concentric with the rotation axis R2 of the workpiece.

[0237] During the non-linear first pass, the first cutting edge 11 of the first cutting insert 2 is active and the second cutting edge 12 is inactive. The second cutting insert 45 is inactive. A first machined surface 38 is generated by a convex nose cutting edge 13. The nose cutting edge 13 is moved towards a first corner face 50. During at least a portion of the first pass 36, the leading edge angle K and the angle β that the first cutting edge 11 forms with respect to the rotation axis R2 of the workpiece are simultaneously changed. The turning method includes increasing the speed of rotation of the turning tool 1 about the tool rotation axis (not shown) when the part of the turning tool 1 that is away from the first cutting insert 2 reaches a predetermined distance 46 from the first side wall 48. Thus, the risk of collision can be reduced. The leading edge angle K is widened during at least a portion of the first pass 36.

[0238] Rotation of the turning tool about the tool's axis of rotation during the first nonlinear pass is in one direction only, i.e., clockwise when viewed as in FIG. 51 with the connection facing away from the viewer.

[0239] Attention is now directed to Figures 53 to 58. The outer groove 52 is machined by a fifth turning tool 1 including the first cutting insert 2 and the second cutting insert 45. Each of the positions of the first turning tool 1 during a portion of the non-linear first pass is shown in chronological order in Figures 53 to 56. The turning tool 1 is moved generally towards the right in Figures 53 to 56, followed by a generally downward movement in Figures 56 to 58. The groove 52 is defined by a first side wall 48, a second side wall 49, a bottom surface 47, a first corner surface 50 and a second corner surface 51. The first corner surface 50 connects the bottom surface 47 and the first side wall 48. The second corner surface 51 connects the bottom surface 47 and the second side wall 49. The bottom surface 47 is a cylindrical surface concentric with the rotation axis R2 of the workpiece.

[0240] During the non-linear first pass, the first cutting edge 11 of the first cutting insert 2 is active and the second cutting edge 12 is inactive. The second cutting insert 45 is inactive. A first machined surface 38 is generated by only the convex nose cutting edge 13. The nose cutting edge 13 is moved towards the first corner face 50. During at least a portion of the first pass 36, the leading edge angle K and the angle β that the first cutting edge 11 forms with respect to the rotation axis R2 of the workpiece are simultaneously changed. The turning method includes increasing the speed of rotation of the turning tool 1 about a tool rotation axis collinear with the longitudinal central axis A1 of the intermediate part 5 of the tool body of the turning tool 1 when the part of the turning tool 1 that is remote from the first cutting insert 2 reaches a predetermined distance 46 from the first side wall 48. Thus, the risk of collision can be reduced. The leading edge angle K is widened during at least a portion of the first pass 36.

[0241] During machining of the bottom surface 47, the cutting angle K and the angle β that the first cutting edge 11 forms with respect to the rotation axis R2 of the workpiece have the same value. During machining of at least a portion of the first corner surface 50, each of the angles has a different value, as can be seen in FIG.

[0242] Attention is now directed to Figures 59 to 62, which show a fifth turning tool 1 particularly suitable for any of the turning methods described above. The fifth turning tool 1 comprises a tool body 3, a first cutting insert 2 and a second cutting insert 45. The tool body 3 comprises a connection portion 4, an intermediate portion 5, a first insert seat 6 for the first cutting insert 2 and a second insert seat for the second cutting insert 45. The tool body 3 extends between the connection portion 4 and a front end 20 of the tool body 3. The front end of the tool body 3 comprises the first insert seat 6 and the second insert seat. The first cutting insert 2 comprises a bottom surface 8 facing the top surface 7 and a side surface 9 connecting the top surface and the bottom surface 7 and 8. An intermediate surface M1 extends midway between the top surface and the bottom surface 7 and 8. The top surface 7 of the first cutting insert 2 faces away from the connection portion 4. The second cutting insert 45 includes a bottom surface 8' facing the top surface 7' and a side surface 9' connecting the top and bottom surfaces 7' and 8'. An intermediate surface M1' extends halfway between the top and bottom surfaces 7' and 8'. The top surface 7' of the second cutting insert 45 faces away from the connecting portion 4. The longitudinal center axis of the connecting portion 4 defines the rotation axis R1 of the tool. The intermediate portion 5 extends along its longitudinal center axis A1. In a top view as seen in FIG. 62, the maximum distance 52 between the first and second cutting inserts 2 and 45 is longer than the width 53 of the front end 20 of the tool body 3. The width 53 of the front end 20 of the tool body 3 is measured perpendicular to the maximum distance 52 between the first and second cutting inserts 2 and 45. As can be seen in FIG. 61, the length 54 of the intermediate portion 5, measured along the longitudinal central axis A1, is greater than the maximum distance 52 between the first and second cutting inserts 2 and 45.

[0243] The upper surfaces 7 and 7' of the first and second cutting inserts 2 and 45, respectively, preferably comprise chip breaking means or chip breakers in the form of one or more protrusions and / or recesses. In Figs. 59 to 64, both cutting inserts have a diamond shape in top view. However, the first and second cutting inserts do not have to have corresponding shapes. Moreover, in top view, the first and second inserts may have any shape. The connection 4 of the fifth turning tool 1 and the connection 4 of the second, third and fourth turning tools follow the connection 4 of the first turning tool 1.

[0244] In this application, the use of words such as "including" is open-ended and is intended to have the same meaning as words such as "comprises" and "comprising" and does not exclude the presence of other structures, materials, or acts. Similarly, the use of words such as "can" or "may" is intended to be open-ended and reflect that a structure, material, or act is not required. Any misuse of such words is not intended to reflect that a structure, material, or act is essential. To the extent that structures, materials, or acts are currently believed to be essential, they are recognized as such. Words such as "upper" or "upwards," "lower," "top," "bottom," "forward," "right," "left," "front," and "rear" refer to objects that one of ordinary skill in the art would recognize as shown in the current drawings.

Claims

1. providing a turning tool (1) comprising a cutting portion (2), the cutting portion (2) comprising a first nose portion (10), the first nose portion (10) comprising a first cutting edge (11), a second cutting edge (12) and a convex nose cutting edge (13) connecting the first and second cutting edges (11, 12), the first and second cutting edges (11, 12) being straight or substantially straight in a top view; Providing a metal workpiece (31); Rotating the metal workpiece (31) about its axis of rotation (R2); making a first pass (36) from the beginning of the cut to the end of the cut, such that the first cutting edge (11) is active and the second cutting edge (12) is inactive, such that a first machined surface (38) is generated by the convex nose cutting edge (13), and such that during at least a portion of the first pass (36), a leading edge angle (K) and an angle (β) that the first cutting edge (11) makes with respect to a rotation axis (R2) of the workpiece are simultaneously changed; 1. A method for turning on a computerized numerically controlled lathe, wherein the first pass (36) is a non-linear first pass (36) beginning with a deepening depth of cut.

2. 2. The method of turning of claim 1, further comprising increasing the entering angle (K) and decreasing a surface producing feed rate during at least a portion of the first pass (36).

3. 3. The turning method according to claim 1 or 2, wherein the entering angle (K) and the angle (β) that the first cutting edge (11) forms with respect to the rotation axis (R2) of the workpiece vary continuously.

4. the leading edge angle (K) and the angle (β) that the first cutting edge (11) forms with respect to the workpiece's axis of rotation (R2) vary with the rotation of the turning tool (1) about the tool's axis of rotation (R1); 4. Method according to any one of the preceding claims, wherein the axis of rotation (R1) of the tool is perpendicular or substantially perpendicular to the axis of rotation (R2) of the workpiece.

5. 5. The method of turning according to claim 1, further comprising moving an axis of rotation (R1) of the tool relative to an axis of rotation (R2) of the workpiece during at least a portion of the first pass (36).

6. 6. The turning method according to claim 1, further comprising moving the turning tool (1) towards an axis of rotation (R2) of the workpiece during at least a portion of the first pass (36).

7. 7. The method according to claim 1, wherein the entering angle (K) and the angle (β) that the first cutting edge (11) forms with respect to an axis of rotation (R2) of the workpiece vary during a non-linear portion of the non-linear first pass (36).

8. 8. The method of any one of claims 1 to 7, further comprising setting a maximum chip thickness (43) to a constant, predetermined value or within a predetermined range during at least a portion of the first pass (36).

9. the first non-linear pass (36) includes machining a bottom surface (47) of an outer groove (52); The groove (5) is defined by a first side wall (48), a second side wall (49), the bottom surface (47), a first corner surface (50) and a second corner surface (51); the first corner surface (50) connects the bottom surface (47) and the first side wall (48); the second corner surface (51) connects the bottom surface (47) and the second side wall (49); moving said nose cutting edge (13) towards said first corner surface (50); 9. The turning method according to any one of claims 1 to 8, comprising increasing the speed of rotation of the turning tool (1) about its axis of rotation (R1) when a part of the turning tool (1) remote from the first cutting insert (2) reaches a predetermined distance (46) from the first side wall (48).

10. 10. The method of any one of claims 1 to 9, further comprising setting a chip area (44) during at least a portion of the first pass (36) to be less than a predetermined value or to be within a predetermined range.

11. 11. The method of any one of claims 1 to 10, further comprising setting a maximum chip width to a predetermined value or within a predetermined range during at least a portion of the first pass (36).

12. making a second pass (37) from the start of the cut to the end of the cut with the second cutting edge (12) active and the first cutting edge (11) inactive; 12. The turning method according to any one of claims 1 to 11, further comprising: at least a portion of the first machined surface (38) being machined during the second pass (37), thereby generating a second machined surface (39) by the convex nose cutting edge (13), the second pass (37) being a non-linear second pass (37) starting with an increasing cutting depth.

13. The cutting part (2) is in the form of a cutting insert (2), The cutting insert (2) comprises an upper surface (7), In a top view, the angle (α) between the first cutting edge (11) and the second cutting edge (12) is less than 90°; In top view, the convex nose cutting edge (13) has a radius of curvature of 0.15 to 1.3 mm; The turning tool (1) comprises a tool body (3), The tool body (3) includes a connection portion (4), an intermediate portion (5), and an insert seat (6); The intermediate portion (5) extends along its longitudinal central axis (A1), The cutting insert (2) is placed on the insert seat (6), The tool body (3) extends between the connecting portion (4) and a front end (20) of the tool body (3); The front end of the tool body (3) includes the insert seat (6), The upper surface (7) of the cutting insert (2) faces away from the connecting portion (4), The longitudinal center axis of said connection part (4) defines the rotation axis (R1) of the tool, 13. The turning method according to any one of claims 1 to 12, wherein the entering angle (K) and the angle (β) that the first cutting edge (11) forms with respect to the workpiece's axis of rotation (R2) vary as a result of a rotation of the turning tool (1) about the tool's axis of rotation (R1) during the first pass (36).

14. 14. The turning method according to claim 13, wherein, in a top view, the intermediate portion (5) extends along a bisector (19) formed between the first and second cutting edges (11, 12) by at least 50% more than along a line perpendicular to the bisector (19) and intersecting the longitudinal central axis (A1) of the intermediate portion (5).

15. A computer program comprising instructions which, when executed by a computer numerically controlled lathe, cause the computer numerically controlled lathe to perform the method of any one of claims 1 to 14.

16. 1. An automated, computer-implemented method of generating commands to control a computer numerically controlled machine to produce features (52) from a metal workpiece (31) rotatable about a rotation axis (R2) of the workpiece with a turning tool (1), comprising: the turning tool (1) comprises a cutting portion (2), the cutting portion (2) comprises a first nose portion (10), the first nose portion (10) comprises a first cutting edge (11), a second cutting edge (12) and a convex nose cutting edge (13) connecting the first and second cutting edges (11, 12); The method, wherein the first and second cutting edges (11, 12) are straight or substantially straight in a top view, configuring a first pass (36) from the beginning of the cut to the end of the cut such that the first cutting edge (11) is active and the second cutting edge (12) is inactive, a first machined surface (38) is generated by the convex nose cutting edge (13), and during at least a portion of the first pass (36), a leading edge angle (K) and an angle (β) that the first cutting edge (11) makes with respect to a rotation axis (R2) of the workpiece are simultaneously changed; The method, wherein the first pass (36) is a non-linear first pass (36) beginning with an increasing depth of cut.

17. 17. The automated, computer-implemented method of claim 16, further comprising setting a maximum chip thickness (43) to a constant, predetermined value or within a predetermined range during at least a portion of the first pass (36).

18. the feature (52) being in the form of an external groove (52) defined by a bottom surface (47), first and second side walls (48, 49), and first and second corner surfaces (50, 51); the first corner surface (50) connects the bottom surface (47) and the first side wall (48); the second corner surface (51) connects the bottom surface (47) and the second side wall (49); the first pass (36) is non-linear and includes machining the bottom surface (47) and the second corner surface (51); Corner cutting angle (K ２ ) and corner exit cutting angle (K ３ ) and the longitudinal exit cutting angle (K ５ ) and setting The cutting angle (K) is defined as the corner cutting angle (K ２ ) and the corner exit cutting angle (K ３ ), and the corner cut angle (K ２ ) and the longitudinal exit cut angle (K ５ 18. The automated, computer-implemented method of claim 16 or 17, further comprising: providing no step or a gradual change in step between the first and second steps.

Images