Turning tool and turning method for CNC-machines

Abstract

A cutting tool for turning includes a coupling portion, an intermediate portion and a cutting portion. The intermediate portion extends along a longitudinal center axis thereof between the coupling portion and the cutting portion. The cutting portion includes a first and a second nose portion. The first nose portion has 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 form a nose angle less than 90°. A longitudinal center axis of the coupling portion defines a tool rotational axis. The cutting portion includes a top surface, the top surface facing away from the coupling portion and the first and the second nose portions each form free ends of the cutting tool.

Claims

1. A cutting tool for turning, the cutting tool comprising a coupling portion, an intermediate portion and a cutting portion, the intermediate portion extending between the coupling portion and the cutting portion, and the intermediate portion extending along a longitudinal center axis thereof, the cutting portion including a first and a second nose portion, the first and second nose portions being permanently connected, the first nose portion comprising 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 forming a nose angle less than 90°, wherein a longitudinal center axis of the coupling portion defines a tool rotational axis, the longitudinal center axis being parallel to or co-linear with the tool rotational axis, the cutting portion having a top surface, the top surface facing away from the coupling portion, wherein the first and the second nose portions each form free ends of the cutting tool, wherein in a top view, the first and second nose portions form an angle of more than 90° relative to each other measured around the longitudinal center axis of the intermediate portion, and wherein in the top view a first extension line co-linear with the first cutting edge and a second extension line co-linear with the second cutting edge extends on opposite sides relative to the longitudinal center axis of the intermediate portion, wherein the coupling portion and the intermediate portion jointly form a tool body, the cutting portion being in the form of a first cutting insert, wherein a front end of the tool body is defined by a first insert seat for the first cutting insert, wherein the first cutting insert is detachably clamped in the first insert seat by clamping means, the first cutting insert including a bottom surface opposite the top surface, wherein a side surface connects the top and bottom surfaces, wherein a mid-plane extends mid-way between the top and bottom surfaces, and wherein the nose cutting edge is in the top view convexly curved having a radius of curvature of 0.15-1.3 mm, wherein the clamping means is in the form of a clamping screw, wherein the first cutting insert includes a hole for the clamping screw, the hole intersecting the top and bottom surfaces, wherein the hole defines a first cutting insert center axis, wherein the first cutting insert center axis is co-linear with the rotational axis, and wherein the longitudinal center axis is co-linear with the tool rotational axis.

2. The cutting tool according to claim 1, wherein the mid-plane is perpendicular to the longitudinal center axis of the intermediate portion.

3. The cutting tool according to claim 1, wherein the first insert seat includes first insert seat rotational locking means, and wherein the first cutting insert includes first cutting insert rotational locking means co-operating with the first insert seat rotational locking means.

4. The cutting tool according to claim 3, wherein the first cutting insert rotational locking means is formed in the bottom surface of the first cutting insert.

5. The cutting tool according to claim 1, wherein the top surface includes chip breaking or chip forming means formed of one or more protrusions and/or depressions.

6. The cutting tool according to claim 1, wherein the first cutting insert is 180° or 120° symmetrical or substantially symmetrical in the top view.

7. The cutting tool according to claim 1, wherein the longitudinal center axis is parallel to and spaced apart from the tool rotational axis and wherein the convex nose cutting edge intersects or substantially intersects the tool rotational axis.

8. The cutting tool according to claim 1, wherein in the top view the intermediate portion is inside an outer boundary line of the coupling portion.

9. The cutting tool according to claim 1, wherein the cutting tool includes a coolant channel, wherein the coolant channel extends between the coupling portion and a nozzle, the nozzle being formed in the intermediate portion, wherein the coolant channel and the nozzle are arranged to direct a coolant fluid towards the first nose portion.

10. The cutting tool according to claim 1, wherein the cutting tool includes a second cutting insert clamped in a second insert seat, wherein the second insert seat is formed in the intermediate portion of the tool body, and wherein the second insert seat is positioned longitudinally between and spaced apart from the first cutting insert and the coupling portion.

11. The cutting tool according to claim 1, wherein the front end of the tool body consists of exactly one insert seat.

12. A turning method for a computerized numerical control lathe comprising the steps of: providing a cutting tool according to claim 1; providing a metal work piece; rotating the metal work piece around a work piece rotational axis; setting the tool rotational axis perpendicular to or substantially perpendicular to the work piece rotational axis; making a first pass such that the first cutting edge is active and such that the second cutting edge is inactive; making a second pass such that the first cutting edge is inactive and such that the second cutting edge is active, where the second pass is longitudinally or radially opposite or substantially opposite to the first pass; and rotating the turning tool around the tool rotational axis during the first pass and/or during the second pass and/or after the first pass but prior to the second pass.

13. The turning method according to claim 12, comprising the further steps of: withdrawing the cutting tool from the metal work piece; and rotating the cutting tool around the tool rotational axis such that the first nose portion is moved away from the metal work piece and such that the second nose portion is moved towards the metal work piece.

14. A computer program having instructions, which when executed by a computer numerical control lathe cause the computer numerical control lathe to perform the method according to claim 12.

Description

DESCRIPTION OF THE DRAWINGS

(1) The present invention will now be explained in more detail by a description of different embodiments of the invention and by reference to the accompanying drawings.

(2) FIG. 1 is a perspective view of a tool body which is part of a cutting tool according to a first embodiment.

(3) FIG. 2 is a perspective view of a cutting tool according to a first embodiment.

(4) FIG. 3 is a perspective view of the insert seat of the tool body in FIG. 1.

(5) FIG. 4 is a side view of the cutting tool in FIG. 2.

(6) FIG. 5 is a further side view of the cutting tool in FIG. 2.

(7) FIG. 6 is a side view of a cutting tool according to a second embodiment.

(8) FIG. 7 is a perspective view of the cutting tool in FIG. 6.

(9) FIG. 8 is a top view of the cutting tool in FIG. 6.

(10) FIG. 9 is a perspective view of a cutting tool according to a third embodiment.

(11) FIG. 10 is a side view of the cutting tool in FIG. 9.

(12) FIG. 11 is a perspective view of the tool body in FIG. 9.

(13) FIG. 12 is a perspective view of the insert seat of the tool body in FIG. 11.

(14) FIG. 13 is a perspective view of the cutting insert in FIG. 9.

(15) FIG. 14 is a side view of the cutting insert in FIG. 13.

(16) FIG. 15 is a top view of the cutting insert in FIG. 13.

(17) FIG. 16 is a further perspective view of the cutting insert in FIG. 13.

(18) FIG. 17 is a side view of a cutting tool according to a fourth embodiment.

(19) FIG. 18 is a further side view of the cutting tool in FIG. 17.

(20) FIG. 19 is a perspective view of the cutting tool in FIG. 17.

(21) FIG. 20 is a top view of the cutting tool in FIG. 17.

(22) FIG. 21 is a start of a first pass according to a turning method using the cutting tool in FIG. 6.

(23) FIG. 22 is an end of a first pass according to a turning method using the cutting tool in FIG. 6.

(24) FIG. 23 is a start of a second pass according to a turning method using the cutting tool in FIG. 6.

(25) FIG. 24 is an end of a second pass according to a turning method using the cutting tool in FIG. 6.

(26) FIG. 25 is an illustration of a first pass according to a turning method using the cutting tool in FIG. 9.

(27) FIG. 26 is an illustration of a second pass according to a turning method using the cutting tool in FIG. 9.

(28) FIG. 27 is an illustration of multiple passes according to a turning method.

(29) FIG. 28 is a side view of a turning method using the cutting tool in FIG. 9.

(30) FIG. 29 is a side view of a turning method using the cutting tool in FIG. 9.

(31) FIG. 30 is a side view of a turning method in FIGS. 25 and 26.

(32) FIG. 31 is a perspective view of the cutting tool and metal work piece shown in FIG. 28.

(33) FIG. 32 is a side view of a turning method using the cutting tool in FIG. 17.

(34) FIG. 33 is a side view of a turning method using the cutting tool in FIG. 17.

(35) FIG. 34 is a side view of a turning method using the cutting tool in FIG. 6.

(36) All cutting tool figures have been drawn to scale.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

(37) Reference is made to FIGS. 1-5 which shows a cutting tool 1 according to a first embodiment comprising a tool body 3 and a cutting insert 2. The tool body 3 is shown in FIG. 1 without the cutting insert 2. The cutting tool comprises an insert seat 6 which is shown in FIG. 3. The cutting tool 1 is a turning tool, comprising a coupling portion 4, an intermediate portion 5 and a cutting portion 2. The coupling portion 4 and the intermediate portion 5 are permanently connected and jointly form a tool body 3 made from steel. The cutting portion 2 is in the form of a first cutting insert 2 made from cemented carbide. The cutting tool 1 according to the first embodiment comprises only one cutting insert.

(38) The coupling portion 4 is suitable to a rotatable machine interface (not shown). The coupling portion 4 comprise a substantially conical or tapered portion 39 and a ring shaped portion 40 in accordance to ISO 26623-1:2014.

(39) A front end 20 or a 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 detachably clamped in the first insert seat 6 by clamping means 14, said clamping means being in the form of a clamping screw 14.

(40) The first cutting insert 2 comprises a bottom surface 8 opposite a top surface 7. A side surface 9 connects the top and bottom surfaces 7, 8.

(41) As seen in FIG. 4, a mid-plane M1 extends mid-way between the top and bottom surfaces 7, 8.

(42) The intermediate portion 5 extends between the coupling portion 4 and the cutting portion 2.

(43) A longitudinal center axis of the coupling portion 4 defines a tool rotational axis R1.

(44) The intermediate portion 5 extends along a longitudinal center axis A1 thereof.

(45) For the cutting tool 1 according to the first embodiment, the longitudinal center axis A1 is co-linear or co-axial with the tool rotational axis R1, as seen in FIGS. 2, 4 and 5.

(46) The mid-plane M1 is perpendicular to the longitudinal center axis A1 of the intermediate portion 5, and perpendicular to the rotational axis R1.

(47) The top surface 7 of the first cutting insert 2 is facing away from the coupling portion 4. The top surface 7 is non-planar, and comprises chip breaking means or chip breakers, in the form of protrusions.

(48) The first cutting insert 2 comprises a first and a second nose portion 10, 10′, which each form free ends of the cutting tool 1,

(49) The first nose portion 10 comprising a first cutting edge 11, a second cutting edge 12, both straight in a top view, and a convex nose cutting edge 13 connecting the first and second cutting edges 11, 12. The convex nose cutting edge 13 is convex in a top view. The nose cutting edge 13 is in top view convexly curved having a radius of curvature of 0.15-1.3 mm. Although a top view of the cutting tool according to the first embodiment is not shown, a top view of the first cutting insert 2 according to the first embodiment is shown in FIG. 8 which show an identical cutting insert. According to the first embodiment, the radius of curvature is 0.4 mm.

(50) The first and second cutting edges 11, 12 forms a nose angle which is 35°.

(51) In a top view, the first and second nose portions 10, 10′ form an angle of 180° relative to each other measured around the longitudinal center axis A1 of the intermediate portion 5.

(52) The first cutting insert 2 is 180° symmetrical symmetric in top and bottom views. The first cutting insert is in a top view parallelogram-shaped.

(53) As seen in FIG. 3, the first insert seat 6 comprises first insert seat rotational locking means comprising ridges 23-26, where two ridges 23, 26 are co-linear, and two ridges 24, 25 are parallel.

(54) The first cutting insert 2 comprises first cutting insert rotational locking means in the form of grooves (not shown), formed in the bottom surface 8, co-operating with the first insert seat rotational locking means 23-26.

(55) The first cutting insert 2 comprises a hole for the clamping screw 14. Said hole 13 intersects the top and bottom surfaces 8, 9, and a center axis thereof defines a first cutting insert center axis co-linear with the rotational axis R1 and the longitudinal center axis A1.

(56) The cutting tool 1 comprising a coolant channel formed in the tool body 3 and extending between the coupling portion 4 and a nozzle 28. Said nozzle 28 is formed in the intermediate portion 5, and the coolant channel and the nozzle 28 are arranged to direct a coolant fluid towards the first and second nose portions 10, 10′.

(57) Reference is now made to FIGS. 9-16 showing a cutting tool 1 according to a third embodiment, comprising a cutting insert 2. The principal differences compared to the cutting tool 1 according to the first embodiment relates to the designs of the cutting insert 2 and the insert seat 6.

(58) In a top view as seen in FIG. 15, a first extension line 21 co-linear with the first cutting edge 11 and a second extension line 22 co-linear with the second cutting edge 12 extends on opposite sides relative to the first cutting insert center axis A2, which axis is co-linear with the rotational axis R1 and the longitudinal center axis A1 when the cutting insert 2 is mounted in the insert seat 6. The previous sentence is true also for the cutting tool 1 according to the first embodiment.

(59) The first cutting insert 2 comprises three nose portions 10, 10′, 10″. The first cutting insert 2 is 120° symmetrical in top and bottom views.

(60) In a top view as seen in FIG. 15 the first and second cutting edges 11, 12 forms a nose angle α which is 35°.

(61) As seen in FIG. 12, the first insert seat 6 comprises first insert seat rotational locking means comprising ridges 23-25, where said ridges 23-25 extend radially in relation to a hole 32 for the clamping screw 14 formed in the first insert seat 6.

(62) The first cutting insert 2 comprises first cutting insert rotational locking means comprising grooves 16-18 formed in the bottom surface 8, co-operating with the first insert seat rotational locking means 23-26.

(63) Reference is now made to FIG. 17-20, showing a cutting tool 1 according to a fourth embodiment. The cutting tool 1 according to the fourth embodiment principally differs from the cutting tool 1 according to the first embodiment in that the cutting tool 1 comprises a second and a third cutting insert 29, 30, clamped our mounted in a second and third insert seat, respectively. Said second and third insert seats are formed in the intermediate portion 5 of the tool body 3 longitudinally between and spaced apart from the first cutting insert 2 and the coupling portion 4.

(64) The second cutting insert 29 and the third cutting insert 30 is each different in shape in a top view compared to the first cutting insert 2. The third cutting insert 30 is a threading insert.

(65) The second and third cutting insert 29, 30 each comprises nose portions, where each of said nose portions comprises a set of cutting edges.

(66) Compared to the first cutting insert 2, the second and third cutting inserts 29, 30 are placed at a greater distance from the longitudinal center axis A1 of the intermediate portion 5.

(67) In a top view as seen in FIG. 20, the second and third cutting inserts 29, 30 forms equally large angles or substantially equally large angles in relation to the first and second nose portions. In FIG. 20, the first cutting insert comprise two nose portions 10, 10′ which are placed at 6 o'clock and at 12 o'clock, respectively. The second cutting insert 29 is placed at 9 o'clock, and the third cutting insert 30 is placed at 9 o'clock, where the time references refers to an analogue 12-hour watch and relates to the relative position in relation to the longitudinal center axis A1. By such a cutting tool, the clearance is further improved.

(68) As seen in FIG. 17, the second and third cutting inserts 29, 30 are positioned longitudinally at equal distances or substantially equal distances from the clamping portion 4.

(69) Reference is now made to FIG. 6-8, showing a cutting tool 1 according to a second embodiment. The cutting tool 1 according to the second embodiment principally differs from the cutting tool 1 according to the first embodiment in that for the cutting tool 1 according to the second embodiment, the longitudinal center axis A1 is parallel to and spaced apart from the tool rotational axis R1, and the convex nose cutting edge 13 of the first nose portion 10 intersects or substantially intersects the tool rotational axis R1. In other words, the intermediate portion 5 is offset in relation to the tool rotational axis R1. A mid-point of the convex nose cutting edge 13 of the first nose portion 10 is positioned less than or equal to 0.5 mm from the tool rotational axis R1.

(70) In other respects, the cutting tool 1 according to the second embodiment is similar to the cutting tool 1 according to the first embodiment. For example, in a top view as seen in FIG. 8 a first extension line 21 co-linear with the first cutting edge 11 and a second extension line co-linear with the second cutting edge 12 extends on opposite sides relative to the longitudinal center axis A1 of the intermediate portion 5.

(71) In accordance with the first, third and fourth embodiment, in a top view as seen in FIG. 8, the intermediate portion 5 and the first cutting insert 2 is inside an outer boundary line of the coupling portion 4.

(72) Reference is now made to FIGS. 21-24 showing a first turning method for a computerized numerical control lathe (not shown). The second embodiment cutting tool 1 is provided, although any of the described embodiments may be used. The cutting insert 2 comprises first and second nose portions 10, 10′. In the method in FIGS. 21-24, the second nose portion 10′ is in an active position. The method can alternatively be performed where the first nose portion 10 is in an active position. In such case, the cutting tool 1 is 180° rotated around the tool rotational axis R1. A metal work piece 31 is provided, which rotates around a work piece rotational axis R2. The tool rotational axis R1 is perpendicular to the work piece rotational axis R2. In the example, the work piece rotational axis R2 is in a horizontal position and the tool rotational axis R1 is in a vertical position. One possible alternative is to arrange the work piece rotational axis R2 is in a vertical position and the tool rotational axis R1 in a horizontal position.

(73) The method comprises the step of making a first pass 36 by moving the cutting tool 1, seen in top view, such that the first cutting edge 11′ is active, such that the second cutting edge 12′ is inactive, and such that a machined surface 38 is formed by the nose cutting edge 13′. The start of the first pass 36 is shown in FIG. 21. The end or the finish of the first pass is shown in FIG. 22.

(74) The method comprises the step of making a second pass 37 by moving the cutting tool 1 such that the first cutting edge 11′ is inactive, such that the second cutting edge 12′ is active, and such that at least a portion of a machined surface 38 from the first pass 36 is machined, where the second pass is longitudinally or radially opposite or substantially opposite to the first pass. The start of the second pass 37 is shown in FIG. 23. The end or the finish of the second pass is shown in FIG. 24. For the method shown in FIGS. 21-24, the second pass is longitudinally opposite to the first pass.

(75) As can be seen from FIGS. 21 and 22, said first pass is linear. Thus, said first pass can be defined by a component 32 which is parallel to the work piece rotational axis R2, i.e. along the work piece rotational axis R2.

(76) As can be seen from FIGS. 23 and 24, said second pass is linear. Thus, said second pass can be defined by a component 33 which is parallel to the work piece rotational axis R2 and opposite to the component 32 for the first direction.

(77) As can be seen in FIGS. 21 and 22, the start and end position for the first pass 36 are spaced apart.

(78) During the first and second passes 36, 37 an entering angle is constant.

(79) After the first pass 36 but prior to the second pass 37, the cutting tool 1 is withdrawn from the metal work piece 31.

(80) After the withdrawing of the cutting tool 1 but prior to the second pass 37, the cutting tool 1 is rotated around the tool rotational axis R1 by an angle which is in the range of 40°-130°.

(81) Attention is now drawn to FIGS. 25-26, which show a second turning method using a cutting tool according to the third embodiment. Only the cutting insert 2 is shown. The method can be used using a cutting tool according to any other embodiment.

(82) A metal work piece 31 is provided, which rotates around a work piece rotational axis R2. The tool rotational axis (not shown) is perpendicular to the work piece rotational axis R2. The method comprises the step of making a first pass, shown in FIG. 25, by moving the cutting tool such that the first cutting edge 11 is active, such that the second cutting edge 12 is inactive, and such that a machined surface 38 is formed by the nose cutting edge 13. Five positions of the cutting insert 2 is shown, starting from the right-hand side and moving towards the left-hand side.

(83) The method comprises the step of making a second pass, shown in FIG. 26, by moving the cutting tool such that the first cutting edge 11 is inactive, such that the second cutting edge 12 is active, and such that at least a portion of a machined surface 38 from the first pass is machined. During the first pass the cutting tool rotates in a first direction, counter-clockwise in FIG. 25, around the tool rotational axis.

(84) During the second pass the cutting tool rotates in a second direction around the tool rotational axis, where said second direction, clock-wise in FIG. 26, is opposite to said first direction.

(85) During the first pass as seen in FIG. 25, the cutting tool is moved along a non-linear or curved line. The first pass comprises a longitudinal component 32 which is towards the left-hand side.

(86) During the second pass as seen in FIG. 26, the cutting tool is moved along a non-linear or curved line. The second pass comprises a longitudinal component 33 which is towards the right-hand side, i.e. opposite to the longitudinal component 32 of the first pass.

(87) During the first and second passes, an entering angle is constant.

(88) After the first pass but prior to the second pass, the cutting tool is withdrawn from the metal work piece 31.

(89) Attention is now drawn to FIG. 27, which show a third turning method. Any turning tool embodiment can be used. A first and second pass 36, 37 is shown. Said first and second passes 36, 37 are similar or substantially similar to the second turning method. The first and second passes 36, 37 are repeated in order to progressively cut a predefined feature into the metal work piece. In other words, the third turning method comprises a series of alternating passes of the cutting tool, where subsequent passes are in opposite or substantially opposite directions.

(90) Attention is now drawn to FIG. 28, showing in a side view the relative position and orientation of a metal work piece 31 and a cutting tool 1 according to the third embodiment. Alternatively, any other cutting tool embodiment can be used. The cutting tool 1 comprises a coupling portion 4 clamped to a machine interface 40 of a CNC-lathe (not shown), an intermediate portion 5 and a cutting portion 2 in the form of a cutting insert. A longitudinal center axis of the coupling portion 4 defines a tool rotational axis R1. The intermediate portion 5 extends along a longitudinal center axis A1 thereof. The cutting portion 2 comprises a top surface facing away from the coupling portion 4.

(91) The metal work piece 31 rotates around a work piece rotational axis R2 in a clock-wise direction in FIG. 28.

(92) The tool rotational axis R1 is perpendicular to the work piece rotational axis R2. The tool rotational axis R1 is arranged such that a tangent line of the metal work piece 31 at the point of contact with the convex nose cutting edge 13 intersect the coupling portion 4. The tangential cutting force is directed towards the machine interface 40. The tool rotational axis R1 is spaced apart by a distance from a peripheral surface of the metal work piece 31. The tool rotational axis R1 is parallel to said tangent line.

(93) Attention is now drawn to FIG. 29, showing the relative position and orientation of a metal work piece 31 and a cutting tool 1 according to the third embodiment. The arrangement in FIG. 29 differs from FIG. 28 only in that the tool rotational axis R1 is not parallel to said tangent line, but forms an angle less than or equal to 10° in relation to said tangent line.

(94) Attention is now drawn to FIG. 30, showing a side view of the center position of the cutting insert 2 from FIGS. 25 and 26, including the cutting tool 1.

(95) Attention is now drawn to FIG. 31, showing a perspective view of the arrangement shown in FIG. 28. The metal work piece 31 shown is cylindrical and comprises a lateral surface 31, i.e. a surface facing away from the work piece rotational axis R2, and a base surface 42, i.e. a surface facing in a direction parallel to the work piece rotational axis R2. The metal work piece 31 comprises a second base surface, facing away from the viewer. In the first, second, third turning methods describe above, as well as in the fourth turning method described below, machining is made in a lateral surface 41 of a metal work piece 31. In other words, material is removed by metal cutting from said lateral surface 41. In the fifth turning method described below, machining is made in a base surface 42 of a metal work piece 31.

(96) Attention is now drawn to FIGS. 32 and 33, showing a fourth turning method, using the cutting tool 1 according to the fourth embodiment.

(97) The method includes any of the above described turning methods, using the first cutting insert 2, where the cutting tool 1 according to the fourth embodiment is in a position relative to the metal work piece 31 as shown in FIG. 32. The method further comprises the steps of withdrawing the cutting tool 1 from the metal work piece 31, and moving the cutting tool 1 in a forward direction along the tool rotational axis R1 to the position shown in FIG. 33. The method further comprises the step of rotating the cutting tool 1 around the tool rotational axis R1 by a predetermined angle, such that the second cutting insert 29 is in an active position.

(98) Said predetermined angle is within the range of 80°-100°

(99) Reference is now made to FIG. 34, showing a fifth turning method using the second embodiment cutting tool 1 is provided, although any of the described embodiments may be used.

(100) A metal work piece 31 is provided, which rotates around a work piece rotational axis R2. The tool rotational axis R1 is perpendicular to the work piece rotational axis R2.

(101) Unlike the previous described turning methods, the machining in the fifth turning method is made at a base surface of the metal work piece 31.

(102) The tool rotational axis R1 is perpendicular to the work piece rotational axis R2. In the example, both the work piece rotational axis R2 and the tool rotational axis R1 is in a horizontal position. One possible alternative is to arrange both the work piece rotational axis R2 and the tool rotational axis R1 in a vertical position.

(103) The cutting insert 2 comprises first and second nose portions 10, 10′. In the method in FIG. 34, the second nose portion 10′ is in an active position. The method can alternatively be performed where the first nose portion 10 is in an active position. In such case, the cutting tool 1 is 180° rotated around the tool rotational axis R1.

(104) The method comprises the step of making a first pass 36 by moving the cutting tool such that the first cutting edge 11′ is active, such that the second cutting edge 12′ is inactive, and such that a machined surface is formed by the nose cutting edge 13′.

(105) The method comprises the step of making a second pass 37 by moving the cutting tool such that the first cutting edge 11′ is inactive, such that the second cutting edge 12′ is active, and such that at least a portion of a machined surface from the first pass 37 is machined.

(106) During the first pass the cutting tool rotates in a first direction, counter-clockwise in FIG. 34, around the tool rotational axis R1.

(107) During the second pass 37 the cutting tool rotates in a second direction around the tool rotational axis, where said second direction, clock-wise in FIG. 34, is opposite to said first direction.

(108) During the first pass 36 the cutting tool is moved along non-linear or curved path. The first pass comprises a radial component 34 which is perpendicular to and towards the work piece rotational axis R2, downwards in FIG. 34.

(109) During the second pass 37 the cutting tool is moved along a path which is non-linear or curved. The second pass comprises a radial component 35 which is perpendicular to and away from the work piece rotational axis R2, upwards in FIG. 34, i.e. opposite to the radial component 34 of the first pass.

(110) During the first and second passes, an entering angle is constant.

(111) After the first pass 36 but prior to the second pass 37, the cutting tool is withdrawn from the metal work piece 31.

(112) In the present application, the use of terms such as “including” is open-ended and is intended to have the same meaning as terms such as “comprising” and not preclude the presence of other structure, material, or acts. Similarly, though the use of terms such as “can” or “may” is intended to be open-ended and to reflect that structure, material, or acts are not necessary, the failure to use such terms is not intended to reflect that structure, material, or acts are essential. To the extent that structure, material, or acts are presently considered to be essential, they are identified as such. Terms such as “upper”, “upwards”, “lower”, “top”, “bottom”, “forward”, “front” and “rear” refer to features as shown in the current drawings and as perceived by the skilled person.