Patent Application
20240058871
The present invention belongs to the technical field of metal cutting. More specifically the present invention belongs to the field of turning.
The present invention refers to a method according to claim 1. In other words, the present invention relates to a turning method for a CNC-lathe.
In metal cutting, turning is a common operation. CNC-lathes are commonly used. Normally, a complex shaped is machined from a metal work piece. To achieve the complex shape, it is common to use two or more turning tools, where the turning tools have different geometrical shape or different orientation. For example, one turning tool can be suitable in machining in one direction, and a second turning tool can be suitable to machine in a different direction.
Conventionally, each turning tool is equipped with one turning in-sert. After turning using one turning insert, normally the first turning tool is indexed to a second turning tool. For example, the CNC-lathe may comprise a turret, and the indexing from one turning tool to a second turning tool is achieved by rotation of the turret by a prede-termined angle. Indexing by rotation of a turret takes time, depend-ing e.g. on the CNC-lathe. The time where there is no cutting, such as when changing or indexing from one tool to another can be called down-time.
EP 1 317 981 A1 disclose a tool carrying a plurality of turning in-serts, whereby switching between different turning inserts can be achieved quickly by means of rotation of the turning tool around a coupling axis.
The inventors have found that there is a need for a further improved method for turning.
It is an object of the invention to provide an improved turning method, especially a turning method where at least two cutting elements are used one after another, where the down-time is reduced. A further object is to provide a method which can be applied on a wide number of CNC-lathes, especially CNC-lathes where the turning tool can not rotate around a center axis thereof. A still further object is to provide a method where a complex shape can be machined in a more effective manner. A still further object is to reduce the number of turning tools, which is done by using only one turning tool in-stead of two or more turning tools. A still further object is to improve the way to machine components of complicated shape with a single turning tool.
At least one of said objectives is achieved by a turning method for a CNC-lathe, comprising the steps of: providing a metal work piece, providing a turning tool, wherein the turning tool comprises a coupling portion, wherein the coupling portion extends along a coupling axis, wherein the turning tool comprises a first cutting element and a second cutting element, wherein the first cutting element comprises a first cutting edge, wherein the second cutting element comprises a second nose cutting edge separating and connecting a second forward cutting edge and a second rearward cutting edge;
rotating the metal work piece in one direction around a rotational axis thereof; moving the turning tool in a first direction such that the first cutting edge is in cut, moving the turning tool in a direction such that the first cutting edge is moved away from the metal work piece and such that the second nose cutting edge is moved towards the metal work piece; moving the turning tool in a second direction such that the second forward cutting edge is in cut at a second entering angle which is 5-45°, wherein the second direction is in the opposite direction or substantially opposite direction to the first direction.
The turning method is for a CNC-lathe i.e. a computer- or computer-ized numerical control lathe, i.e. any CNC-machine suitable for turning such as e.g. a turning lathe, a multitask machine, a turn-mill machine, or a sliding head machine. A metal work piece is provided.
The metal work piece comprises an external surface, which is a radially outer surface. The radially outer surface is facing away from the rotational axis. The turning method is for turning of the radially outer surface, i.e. external turning. The metal work piece extends between a first end and a second end. The metal work piece is clamped by clamping means. The clamping means holds the metal work piece and are at least partially controlled and driven by a mo-tor or a spindle.
The clamping means may be in the form of a collet chuck, a face driver, or a 3-jaw chuck, and may comprise a tail stock. The head-stock end of the machine is preferably located at the first end of the metal work piece. A second end of the metal work piece, opposite to the first end of the work piece, may be a free end. Alternatively, the second end is in contact with a tailstock or a second chuck. A turning tool is provided. The turning tool comprises a forward end and an opposite rear end in the form of a coupling portion. The coupling portion is connected to the CNC-lathe, more specifically to a machine interface of the CNC-lathe, such as a machine spindle or a tool revolver turret or a tool post.
The coupling portion may have a square or rectangular shape in a cross section. The coupling portion may be conical or substantially conical such as preferably according to ISO standard 26623-1. In this context, a truncated cone is a cone-like shape. In this context, the tapered portion which forms the rear part of the ISO standard 26623-1 coupling is a cone-like shape. The coupling portion is preferably conical such that said cone or cone-like shape is symmetrical or substantially symmetrical around the coupling axis. A three-fold symmetry is in this context considered to be symmetrical. A cross section area of said cone or cone like shape preferably decreases in a rearward direction. The coupling portion may be in the form of a hollow taper shank such as HSK, according to DIN 69893.
The coupling portion extends along a coupling axis or a center axis, which center axis defines a longitudinal axis of the turning tool. The length, i.e. total length, of the turning tool measured along or parallel to the coupling axis is preferably 50-400 mm, even more preferably 70-300 mm.
The turning tool comprises a first cutting element and a second cutting element. The first and second cutting elements are spaced apart. The first and second cutting elements are preferably cutting inserts or turning inserts, i.e. replaceable elements made from a wear resistant material, e.g. cemented carbide. Alternatively, the first and second cutting elements can be parts of a single wear resistant element, preferably made from a single piece of cemented carbide. The first cutting element comprises a first top surface. The first top surface comprises a rake face or a rake surface.
The first cutting element comprises a first cutting edge. The first cutting edge may preferably be in form of a nose cutting edge, i.e. a cutting edge which is convex in a top view. The first cutting edge, or a portion of the first cutting edge, generate the machined surface. The first cutting element may be in the form of a round cutting in-sert, i.e. an insert which is circular or substantially circular in a top view. The radius of said circle is preferably 5-30 mm. Alternatively, the first cutting edge may be a nose cutting edge which is convex in a top view, preferably in the form of a circular arc, having a radius of curvature of 0.2-1.6 mm, and be arranged between, i.e. connecting, a first forward cutting edge, i.e a main cutting edge or a principal cutting edge or a leading cutting edge, and a first rearward cutting edge, i.e. an auxiliary cutting edge or a trailing cutting edge. The second cutting element comprises a second nose cutting edge separating and connecting a second forward cutting edge and a second rearward cutting edge. The second cutting element comprises a first top surface. The second top surface comprises a rake face or a rake surface. The second forward cutting edge is a leading cutting edge. The second rearward cutting edge is a trailing cutting edge.
The first top surface may in a top-view have a rhomb-shape, a tri-angular shape, an octagonal shape, a square shape, a round shape, or a polygon shape.
The first top surface and the second top surface may each be flat.
Alternatively, one or both of said surfaces may be non-flat or non-planar. Preferably, said surfaces may comprise one or more chip breaking means, in the form of one or more protrusions and/or depressions.
The direction which the first top surface is facing is a normal to the first top surface, i.e. a direction perpendicular to the first top surface. Said direction is away from the first top surface, and away from the first bottom surface, in case the first cutting element is in the form of a cutting insert or a turning insert, having a first bottom surface.
In case the first top surface is non-flat, for the purpose of determine the direction which the first top surface is facing, such first top surface may be defined as or approximated to a plane parallel to a first mid-plane, where said plane intersects the first cutting edge, or at least a portion of the first cutting edge. Said first mid-plane is a plane mid-way between the first top surface and the first bottom surface, in case the first cutting element is in the form of a cutting insert or a turning insert, having a first bottom surface.
Alternatively said first top surface, for the purpose of determine the direction which the first top surface is facing, may be defined as a plane intersecting all nose cutting edges bordering to or adjoining the first top surface.
A corresponding reasoning applies for the second top surface and the second cutting element.
The method comprises the step of rotating the metal work piece in one direction around a rotational axis thereof. The one direction may be clock-wise or counter clock-wise.
The method includes the step of moving the turning tool in a first direction, i.e. in a first feed direction. In other words, the method includes the step of turning in a first direction.
The first direction may preferably be parallel to the rotational axis, also known as longitudinal turning. Said step is included in a first pass, which is defined as between going into cut and going out of cut. The first pass is not necessarily a movement of the first cutting element along a straight line. When turning in the first direction, the first cutting edge is in cut, i.e. is active. A machined surface is formed by the first cutting edge.
After or during going out of cut, the turning tool is moved such that the first cutting edge is moved away from the metal work piece and such that the second nose cutting edge is moved towards the metal work piece. During at least a portion of said movement, neither the first cutting element nor the second cutting element is active, i.e. no metal cutting by the first and second cutting elements during said movement.
The movement of the turning tool may be in a direction perpendicular to the coupling axis and the rotational axis. The movement of the turning tool may preferably be or include a linear movement. Said movement is preferably without rotation around the coupling axis. Thus, the method can be applied on a wide range of CNC-lathes. The movement may be in a direction which is perpendicular to or substantially perpendicular to the first top surface.
Said movement is an indexing motion. In other words, the movement is such that the first cutting element is brought to an inactive position and the second cutting element is brought to an active position, i.e. a position where the second element is suitable to cut metal from the metal work piece.
The method includes the step of moving the turning tool in a second direction. In other words, turning in a second direction. The second direction, or second feed direction, is in the opposite direction or substantially opposite to the first direction. For example, the first direction and second direction may be parallel to the rotational axis, but in opposite directions. For example, the first direction may be in a direction away from a first end of the work piece, and the second direction may be towards said first end of the work piece. Said first end may be a clamping end, i.e. the end of the work piece which is clamped by clamping means. Said step of moving the turning tool in a second direction is included in a second pass, which is defined as between going into cut and going out of cut. The second pass is not necessarily a movement of the first cutting element along a straight line. A machined surface is formed by the second nose cutting edge. The second nose cutting edge and the second forward cutting edge is active, such that the second forward cutting edge is active at an acute second entering angle. The acute second entering angle is preferably 5-45°, even more preferably 5-30°. By such an acute entering angle, the insert wear of the second cutting element is reduced, compared to if the second entering angle is greater. The second entering angle is the entering angle of the second forward cutting edge when moving the turning tool in the second direction. The second cutting element is inactive, i.e. not cutting, in other words spaced apart from the metal work piece, when moving the turning tool in the first direction. The first cutting element is inactive, i.e. not cutting, in other words spaced apart from the metal work piece, when moving the turning tool in the second direction. Preferably, no part of the turning tool is between the first cutting edge and the second nose cutting edge. In other words, no part of the turning tool is preferably located along a straight line connecting the first and second nose cutting edges.
According to an embodiment, the first cutting element comprises a first forward cutting edge and a first rearward cutting edge, wherein the first cutting edge is a first nose cutting edge, wherein the first nose cutting edge separates and connects the first forward cutting edge and the first rearward cutting edge, wherein when moving the turning tool in a first direction, the first forward cutting edge forms a first entering angle which is 5-45°.
By such a method, the wear of the first cutting element is reduced, compared to if the first entering angle would be greater.
The first forward cutting edge, which is a principal cutting edge or a main cutting edge, and the first rearward cutting edge, which is an auxiliary cutting edge, are each preferably straight or linear or substantially straight or substantially linear in a top view. The first nose cutting edge is convex in a top view, preferably in the form of a circular arc, preferably having a radius of curvature of 0.2-1.6 mm. The nose angle of the first cutting element, defined as the angle between the first forward cutting edge and the first rearward cutting edge, is preferably less than or equal to 160°, even more preferably 30°80°.
The first forward cutting edge forms an acute first entering angle, said first entering angle is 5-45°, even more preferably 5-30°.
When moving the turning tool in the first direction, the first nose cutting edge and the first forward cutting edge are in cut or active. The first and second nose cutting edges are preferably spaced apart along the rotational axis by a constant distance when turning in the first and second directions.
According to an embodiment, the method comprises the further step of moving the turning tool in the second direction such that the second rearward cutting edge forms an obtuse back clearance angle.
By such a method, a surface perpendicular to the rotational axis can be machined by the second cutting element. The method may comprise the step of moving the turning tool radially towards the rotational axis such that the second cutting element is in cut. Preferably said step is prior to the step of moving the turning tool in the second direction.
Preferably, said back clearance angle is 91°135°, even more preferably 93°120°. The sum of the entering angle, the nose angle and the back clearance angle equals 180°. This applies to both the first and second cutting elements.
According to an embodiment, the method comprises the step of moving the turning tool in the first direction such that the first rearward cutting edge forms an obtuse back clearance angle.
By such a method, a surface perpendicular to the rotational axis can be machined by the first cutting element. The method may comprise the step of moving the turning tool radially towards the rotational axis such that the first cutting element is in cut. Prefera-bly said step is prior to the step of moving the turning tool in the first direction.
Preferably said back clearance angle is at least 91°, even more preferably 93°120°.
According to an embodiment, the method comprises the step of turning at least a portion of a surface machined when moving the turning tool in the first direction when moving the turning tool in the second direction.
By such a method, a roughing and a finishing operation can be made using only one turning tool.
The method may comprise the further step of moving the turning tool in the first direction, such that the first cutting element is in cut, and such that at least a portion of the surface machined when mov-ing the turning tool in the second direction is machined.
The method may comprise further steps, such that the first and second cutting element is alternatively in cut in a sequence, where the first cutting element is in cut when the turning tool is moved in the first direction, and the second cutting element is in cut when the turning tool is moved in the second direction.
According to an embodiment, the step of moving the turning tool in a direction such that the first cutting edge is moved away from the metal work piece and such that the second nose cutting edge is moved towards the metal work piece, is without rotation of the turning tool around the coupling center axis.
Said movement is without rotation of the turning tool around the coupling axis, or around any other axis parallel to the coupling axis. By this, the method can be applied on a wide number CNC-machines. Said movement can be a linear movement, or the turning tool can move nonlinearly, e.g. in a circular arc, in a plane defined by two machine axii, such as the X-Z plane of the CNC-lathe. By this, the indexing time can be shorter, compared to a rotational movement. One other effect of a linear movement is that the method can be performed using CNC-lathes where there is no rotating option.
Preferably, the turning tool does not rotate around the coupling axis during the first pass, the second pass or between the first and second passes. Preferably, the turning tool does not rotate around any other axis, such as any axis parallel to the coupling axis, during or between the first and second passes. In other words, the method is preferably without any rotational movement of the turning tool.
According to an embodiment, the coupling axis is parallel to or per-pendicular to the rotational axis.
By such a method, the said method can be applied on a greater number of CNC-lathes. The coupling axis is parallel to or perpen-dicular to the rotational axis when turning in the first and second directions, preferably during all steps of the method.
According to an embodiment, the metal work piece is clamped by clamping means, wherein a distance from the clamping means to the second nose cutting edge is shorter than a distance from the clamping means to the first cutting edge.
Said clamping means are connected to and driven by a rotating or rotatable spindle. Said clamping means may be in the form of e.g. a collet chuck, a 3-jaw chuck or a face driver. Said distance is meas-ured along or parallel to the rotational axis.
According to an embodiment, the second nose cutting edge is in the first direction ahead of the first cutting edge when moving the turning tool in the first direction, wherein the first cutting edge is in the second direction ahead of the second nose cutting edge when mov-ing the turning tool in the second direction.
By such a method, the more shapes can be machined, because the is less risk that an inactive cutting element interferes with the metal work piece. Ahead is to be understood as ahead in the feed direc-tion, along the rotational axis. More specifically, the second nose cutting edge is ahead of the surface generating part of the first cutting edge when moving the turning tool in the first direction, wherein the surface generating part of the first cutting edge is ahead of the second nose cutting edge when moving the turning tool in the second direction. The surface generating part of the first cutting edge is preferably in the form of a first nose cutting edge.
According to an embodiment, the second direction is in a direction away from a corner of the metal work piece.
A corner, or a shoulder, is defined as the intersection between a first surface concentric with the rotational axis, and a second surface perpendicular to the rotational axis. The first surface may be an external surface or an internal surface, i.e. a surface inside a bore. Preferably, the first surface is an external surface, i.e. a radi-ally external surface. Said corner is preferably a 90° corner. Said corner is preferably completely or at least partly formed by the second cutting element.
According to an embodiment, the method comprises the further step of turning in a third direction such that the second forward cutting edge is active at an obtuse third entering angle, wherein the third direction is towards the rotational axis.
By such a method, a more complicated component shape can be machined by the one turning tool. The step of turning in the third direction is preferably after turning in the first direction. The step of turning in the third direction is preferably prior to turning in the second direction. The step of turning in the third direction is preferably part of the second pass, such that the second cutting element is in cut or active continuously when turning both in the third and second directions. The second pass is thus preferably non, linear. The third entering angle is preferably at least 100°, more preferably at least 110°. The third direction is preferably perpendicular to and towards the rotational axis. When turning in the third direction a surface is formed by the second nose cutting edge.
Preferably, an external corner or external shoulder is formed by turning in the third and second directions. Said external corner is formed by two surfaces, where one first surface is cylindrical or conical, and one second surface is flat or conical. Said two surfaces are connected by a curved surface.
Preferably, said corner or shoulder is defined by a first surface con-centric with the rotational axis and a second surface perpendicular to the rotational axis. The first surface may be an external surface or an internal surface, i.e. a surface inside a bore. Preferably, the first surface is an external surface, i.e. a radially external surface. The first and second surfaces are connected by a curved surface. Said curved surface is preferably in the form of a circular arc when seen in a plane comprising the rotational axis. Said circular arc has a radius which is greater than or equal to the radius of the second nose cutting edge.
The first direction is preferably in a direction towards a corner, i.e. said corner. In other words, the first pass is in a direction towards a would be corner, preferably a corner which is finished after the second pass. The first pass thus comprises a roughing of a corner, i.e. removing some but not all material for a desired or predefined shape.
According to an embodiment, the first cutting element is a first turning insert, wherein the second cutting element is a second turning insert, wherein the first turning insert comprises a first top surface and a first bottom surface, wherein the first top surface and the first bottom surface are connected by a first side surface, wherein the second turning insert comprises a second top surface and a second bottom surface, wherein the second top surface and the second bottom surface are connected by a second side surface, wherein the first top surface and the second top surface comprises chip breaking means.
The first turning insert comprises the first cutting edge, the first for-ward cutting edge and the first rearward cutting edge. The second turning insert comprises the second nose cutting edge, the second forward cutting edge and the second rearward cutting edge.
The first top surface comprises a rake surface. The second top surface comprises a rake surface. Each of the first and second bottom surfaces comprises a seating surface or a contact surface.
Preferably, a first through hole for a first screw intersects the first top and first bottom surfaces.
Preferably, a second through hole for a second screw intersects the second top and first bottom surfaces.
The chip breaking means may be in the form of one or more protru-sions and/or depressions. Said one or more protrusions and/or depressions are preferably arranged to control or break chips. Said protrusions preferably protrude above the cutting edge bordering the top surface, when the insert is seen in a side view. Chip break-ing means improves chip breaking in turning.
According to an embodiment, the coupling portion is square or rec-tangular in a cross section or comprises a conical or substantially conical portion.
Said cross section is in a plane perpendicular to the coupling axis. The coupling portion preferably comprise a conical or substantially conical portion and a ring-shaped portion, such as preferably in the form of a polygonal hollow taper interface with a flange contact surface, such in accordance to ISO 26623-1:2014, or a hollow taper with a flange contact surface such as in accordance to DIN 69893, ISO 12164-1 or ISO 12164-1F.
According to an embodiment, the method comprises the further step of arranging the turning tool such that the metal work piece is between the first cutting edge and the second nose cutting edge.
By such a method, the indexing between the first and second ele-ment can be made through a linear movement along the coupling axis. Such a method can be used on a high number of CNC-lathes. The metal work piece is thus between the first cutting edge and the second nose cutting edge when turning in the first direction, and when turning in the second direction.
Preferably, the rotational axis is between or substantially between the first cutting edge and the second nose cutting edge. In other words, the turning in the first direction with the first cutting element and the turning in the second direction with the second cutting ele-ment are on opposite sides in relation to the rotational axis of the metal work piece. Preferably, a rake face associated with the first cutting edges and a rake face associate with the second cutting edges are facing in opposite or substantially directions.
According to an aspect of the invention, there is provided a com-puter program having instructions which when executed by a CNC-lathe causes the CNC-lathe to perform the steps according to any of the preceding methods.
Said computer program, or computer program product, may be in-cluded in a CAM-software product, i.e. a software for computer-aided manufacturing. Said computer program may be in the form a computer readable medium such as a USB-stick, a CD-ROM or a data stream.
The present invention will now be explained in more detail by a de-scription of embodiments of the invention and by reference to the accompanying drawings.
All turning tools in the figures are drawn to scale.
Reference is made to
As seen in
As seen in
In
The intermediate portion 33 comprises a first side surface 40 and an opposite second side surface. Due to the opening 41, the first side surface 40 does not surrounds or encloses the rotational axis A1. The first side surface 40 is extends in a plane which is perpen-dicular to the rotational axis A1. Said plane 40 is spaced apart from the coupling axis A2.
Protruding from the first side surface 40 are protruding portions 30, 31 in the form of replaceable cutting heads 30, 31, which are con-nected to the first side surface by clamping means. Each cutting head 30, 31 comprises at least one insert seat. The first and second turning inserts 7, 8 are connected to the first side surface 40 by means of a respective cutting heads 30, 31.
In
Coromant Capto®. In an alternative embodiment (not shown), the coupling portion 3 is square shaped in a cross section, and the coupling axis A2 is parallel to the coupling axis A2 in
When the first turning insert 7 is seen in a top view, as in e.g.
As seen in e.g.
The first forward cutting edge 12 forms an acute first entering angle. The first rearward cutting edge 14 forms an obtuse first back clearance angle. The first turning insert 7 is in cut. The second turning insert 8 is spaced apart from the metal work piece 2. The second nose cutting edge 6 is in the first direction 17 ahead of the first nose cutting edge 5.
After the step shown in
After the step shown in
The metal work piece 2 rotates in the same direction around the ro-tational axis thereof A1 in
Reference is now to
As seen in e.g.
As seen in e.g.
The coupling portion 3 defines the rear end of the turning tool 1 and is suitable for being insert into a machine interface (not shown) which preferably comprise a cavity or a recess (not shown). The coupling portion 3 shown in e.g.
When moving the turning tool 1 in the first direction 17, the second nose cutting edge 6 is ahead of the first nose cutting edge 5. As seen in
Reference is now made to
Capto®. The couping portion may have other shapes, such a shape which is square shaped or rectangular shaped in a cross section, where said cross section is perpendicular to the coupling axis., The turning tool 1 comprises a first cutting element 7 in the form of a first turning insert 7, a second cutting element 8 in the form of a second turning insert 8, and a third cutting element 9 in the form of a third turning insert 9. The first turning insert 7 comprises a first cutting edge 5 in the form of a first nose cutting edge 5, a first for-ward cutting edge 12 and a first rearward cutting edge 14. The first nose cutting edge 5 separates and connects the first forward cutting edge 12 and the first rearward cutting edge 14. The first turning in-sert 7 comprises a first top surface 20 and an opposite first bottom surface. The second turning insert 8 comprises a second nose cutting edge 6, a second forward cutting edge 13 and a second rearward cutting edge 15. The second nose cutting edge 6 separating and connecting a second forward cutting edge 13 and a second rearward cutting edge 15. In other words, the second forward cutting edge 13 and a second rearward cutting edge 15 converge towards the second nose cutting edge 6. The second cutting element 8 comprises a second top surface 21 and an opposite second bottom surface.
A first mid-plane P1 extends mid-way or substantially mid-way between the first top surface 20 and the first bottom surface. The first mid-plane P1 is parallel to or substantially parallel to the first bottom surface. In a corresponding manner, the second turning insert 8 comprises a second top surface 21 and an opposite second bottom surface, wherein a second mid-plane P2 extends mid-way or substantially mid-way between the second top surface 21 and the second bottom surface. The third turning insert 9 is arranged in a corresponding manner, having a third mid-plane P3 mid-way between a top and a bottom surface thereof. Said top surfaces 20, 21 are suitable to function as rake surfaces. The first, second and third mid-planes P1, P2, P3 extends in parallel or substantially parallel planes. As seen in e.g.
As seen in
In
CNC-lathe (not shown). A metal work piece 2 is rotating in one direction 50 around a rotational axis A1 thereof. The coupling portion 3 of the turning tool 1 is connected to the CNC-lathe (not shown), more specifically the coupling portion is connected to a machine interface. The coupling axis A2 is perpendicular to the rotational axis
A1. The turning tool 1 is moved in a first direction 17 such that the first nose cutting edge 5 is in cut and such that the first forward cutting edge forms an acute entering angle. The first rearward cutting edge 14 forms an obtuse back clearance angle. The second and third turning inserts 8, 9 are spaced apart from the metal work piece 2. The second nose cutting edge is ahead of the first nose cutting edge 5 in the first direction 17. The first direction is parallel to the rotational axis A1.
After the first step, the turning tool 1 is moved in a direction 19 per-pendicular to the coupling axis A2 and perpendicular to the rotational axis A1, as seen in
The metal work piece can have a different shape compared to what has been described above. The metal work piece may be in the form of a bar, a hollow bar or any other shape which has a rotational symmetry or substantially has a rotationally symmetry around a rotational axis thereof. The shape which can be machined can be of different configurations than what have been described above. For example, the shape can have not only one, but two side walls, i.e. surfaces which is in a plane perpendicular to the rotational axis. In other words, the turning tool can be used to machine an external groove.
The metal work piece 2 in
The first and second turning inserts 7, 8 described in the embodiments above are preferably made from a wear resistant material, preferably cemented carbide. The first and second top surfaces 20, 21 preferably comprises chip forming means or chip breaking means (not shown). Preferably, a distance from at least a portion of said chip forming means or chip breaking means to the mid-plane of the respective turning insert is greater than a distance from the cutting edge bordering to the top surface to said mid-plane. In other words, the top surfaces 20, 21 of the first and second turning in-serts comprises at least one protrusion, which in a side view is higher than or above the cutting edge. In such a way, the turning inserts are more suitable for turning.
The first and second turning inserts 7, 8 described in the embodiments above are preferably designed such that the first forward cutting edge 12 is sloping downwards, i.e. towards the first bottom surface 22, at increasing distance from the first nose cutting edge 5. The second forward cutting edge 13 is preferably arranged in a corresponding manner. In such a way, the chip control is further improved.
The forward and rearward cutting edges are forward and rearward in the respective feed directions, not necessarily forward or rearward in relation to forward or rearward directions of the turning tool itself.
| Number | Date | Country | Kind |
|---|---|---|---|
| 20214135.4 | Dec 2020 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2021/080451 | 11/3/2021 | WO |
