machine tool

Abstract

A machine tool (1), in particular for machining bush-like or sleeve-like workpieces (2), comprising a machine frame (3), a workpiece carriage (4) movable in an x-direction, a workpiece clamping device (6) arranged on the workpiece carriage (4) so ​​as to be movable in a z-direction and rotatably driven about a rotational axis (32) running in the z-direction, a stationary second workpiece clamping device (10) arranged on the machine frame (3) and rotatably driven about a rotational axis (33) running in the z-direction, a stationary first tool holder (7) arranged on the machine frame (3) for internally machining a workpiece (2) clamped in the first workpiece clamping device (6), a stationary second tool holder (9) arranged on the machine frame (3) for externally machining a workpiece (2) clamped in the first workpiece clamping device (6) arranged workpiece (2), a tool slide (12) movable in the x-direction,which comprises a third tool holder (13) movable in the x-direction for externally machining a workpiece (2) clamped in the second workpiece clamping device (10), characterized in that the third tool holder (13) has exactly one degree of rotational freedom and a tool axis (36) running in the x-direction can be driven in rotation and / or that the first tool holder (7) has at most one degree of rotational freedom and can be driven in rotation about at most a tool axis (35) running in the z-direction, wherein a rotational axis (32) of the first workpiece clamping device (6) and a rotational axis (33) of the second workpiece clamping device (10) lie on a straight line running in the z-direction at a transfer position (31).

Description

[0001] The invention relates to a machine tool, in particular for machining bushing-type or sleeve-type workpieces. Furthermore, the invention relates to a method for machining bushing-type or sleeve-type workpieces.

[0002] Machine tools with multiple tool holders and multiple workpiece clamping devices are known from the prior art, for example from DE 10 2009 009 969 B4.

[0003] State-of-the-art machine tools have the disadvantage that high accuracies, which are necessary for cylinder machining, for example, cannot be achieved and subsequent machining, for example by grinding or honing, is necessary.

[0004] The invention is based on the object of providing a machine tool which can achieve high accuracies in cylinder machining.

[0005] The object is achieved by a machine tool having the features of claim 1. According to the invention, it was recognized that a third tool holder, which has exactly one rotational degree of freedom and which can be driven in rotation about a tool axis running in the x-direction and / or a first tool holder, which has at most one rotational degree of freedom and which can be driven in rotation about a tool axis running in the z-direction, enable high precision in the machining of workpieces, in particular bush-like or sleeve-like workpieces, in particular thin-walled bush-like or sleeve-like workpieces. The first tool holder can in particular have exactly one rotational degree of freedom. The first tool holder can in particular have no rotational degree of freedom.By limiting the rotational degrees of freedom of the first and third tool holders, the stability of the tool holder can be increased, which in turn leads to increased accuracy. The stability of the first tool holder is further increased by its fixed arrangement on the machine frame.

[0006] Bushing-type workpieces are geometric elements that have an opening on two opposite sides, connected by a through-hole. Bushing-type workpieces are geometric elements that are closed on one side, i.e., elements with a hole that is not a through-hole.

[0007] A stationary attachment means that there is no linear degree of freedom. The stationary first tool holder cannot be moved in the x, y, or z directions.

[0008] The maximum one degree of rotational freedom of the first tool holder can be achieved by the ability to rotate around a tool axis running in the z-direction. This degree of rotational freedom can only enable an internal turning tool for internal machining of the workpieces to be driven in rotation. Alternatively, the first tool holder can have no degree of rotational freedom.

[0009] The third tool holder's exact one degree of rotational freedom is provided by a tool change function, for example, in the form of a tool turret. Rotation occurs around a tool axis running in the x-direction. Alternatively, the third tool holder can be designed without a tool change function and thus have no degree of rotational freedom.

[0010] The alternative designs of the third tool holder without rotational degree of freedom can further increase the stability of the first and third tool holders and improve the accuracy.

[0011] The machine frame serves as the basic framework of the machine tool and as the mounting location for the machining stations. The machine frame ensures the relative position between the workpiece clamping devices and the tool holders. This ensures high accuracy when approaching the shared machining positions of the workpiece clamping devices and the tool holders.

[0012] By means of the workpiece carriage which can be moved in the x-direction with the first workpiece clamping device which can be moved in the z-direction and which can be driven in rotation about a rotation axis running in the z-direction, a workpiece to be machined can be moved both into a machining position for external machining with the tools clamped in the second tool holder and into a machining position for internal machining of the workpiece with the tools clamped in the first tool holder.

[0013] Due to the ability of the first workpiece clamping device to rotate about an axis running in the z-direction, degrees of freedom in the first and second tool holders can be dispensed with, since rotation of the workpiece during external and / or internal machining can be carried out by the first workpiece clamping device.

[0014] For internal machining, a relative rotational movement can be performed by the first tool holder and the first workpiece clamping device. Alternatively, the rotational movement for internal machining can be performed solely by the workpiece clamping device or by the first tool holder.

[0015] The stationary arrangement of the second workpiece clamping device results in high precision during machining of the workpiece by the tool clamped in the third tool holder. The stationary arrangement of the second workpiece clamping device firmly defines the position of the workpiece to be machined. Furthermore, movement of the second workpiece clamping device due to machining forces is prevented.

[0016] The tool slide, which can be moved in the x-direction, and the third tool holder, which is attached to it and can be moved in the z-direction, allow the tool clamped in the third tool holder to be brought into the machining position and both the infeed and feed movements to be carried out.

[0017] The tool slide can have a gripper. The gripper can be mounted on the tool slide so that it can move in the z-direction. The gripper can grip a workpiece clamped in the second workpiece clamping device and remove it from the second workpiece clamping device. The workpiece gripped by the gripper can then be placed outside the machining area of ​​the machine tool.

[0018] Two simultaneous machining operations can take place in the machine tool. A first workpiece, clamped in the first workpiece clamping device, and a second workpiece, clamped in the second workpiece clamping device, can be machined simultaneously. Simultaneous machining can increase the system's throughput. Alternatively, a single workpiece can be completely machined until the next workpiece is transferred to the machine tool.

[0019] A machine tool according to claim 2 increases the variability of the machine tool and / or reduces maintenance effort. By providing a tool change function on the third tool holder, for example, several similar tools can be provided. The tools can be changed after the first tool has worn out, whereby maintenance of the machine tool by replacing the tools is only necessary when all tools are worn out.

[0020] Alternatively, different types of tools can be provided in a tool changer. This allows the workpiece to be machined in stages using the third tool holder. For example, rough machining can be performed first with a first tool, followed by fine machining with a second tool. Alternatively, machining can be performed in more than two steps using more than two different tools.

[0021] A machine tool according to claim 3 increases the positioning accuracy of the tool clamped in the second tool holder by limiting the rotational degrees of freedom. By increasing the positioning accuracy of the tool, the accuracy of the machining process can also be increased.

[0022] A machine tool according to claim 4 represents a preferred embodiment. The ability to rotate about a tool axis running in the x-direction can be used, for example, to change a tool.

[0023] A machine tool according to claim 5 increases the variability of the machine tool and / or reduces maintenance effort. By providing a tool change function on the third tool holder, for example, several similar tools can be provided. The tools can be changed after the first tool has worn out, whereby maintenance of the machine tool by replacing the tools is only necessary when all tools are worn out.

[0024] Alternatively, different types of tools can be provided in a tool changer. This allows the workpiece to be machined in stages using the third tool holder. For example, rough machining can be performed first with a first tool, followed by fine machining with a second tool. Alternatively, machining can be performed in more than two steps using more than two different tools.

[0025] A machine tool according to claim 6 enables the automatic feeding of raw parts. The raw parts fed by the feeding device can be picked up by the first workpiece clamping device without manual intervention. This enables automated operation of the machine tool.

[0026] A machine tool according to claim 7 enables the automatic removal of finished workpieces without manual intervention. The removal device allows finished workpieces to be automatically removed from the machine tool and fed to the next process step, for example, quality control or shipping. Alternatively, the finished workpieces can be fed to another processing location.

[0027] Particularly advantageously, the machine tool has both a feed device and a discharge device. By providing a feed device and a discharge device, the machine tool can be integrated into a fully automated production line.

[0028] A machine tool according to claim 8 enables automatic operation of the machine tool by automated transfer of the workpiece from the first workpiece clamping device to the second workpiece clamping device.

[0029] Because the workpiece carriage can be moved in the x-direction, the first workpiece clamping device can also be moved to a transfer position, where the workpiece is transferred from the first workpiece clamping device to the second workpiece clamping device. For this purpose, the workpiece carriage is moved such that an axis of the first workpiece clamping device running in the z-direction and an axis of the second workpiece clamping device running in the z-direction lie on a straight line running in the z-direction. The workpiece is then transferred to the second workpiece clamping device by a movement of the first workpiece clamping device in the z-direction.

[0030] A machine tool according to claim 9 enables various relative movements for the internal machining of the workpiece while maintaining sufficient machine tool stability to achieve the desired tolerances. In particular, the rotational movement for the internal machining can be generated either by the first workpiece clamping device, by the first tool holder, or by superimposing the rotational movement of the first workpiece clamping device and the first tool holder.

[0031] A machine tool according to claim 10 increases the stability of the first tool holder and thus enables very precise internal machining of the workpiece and high tolerances.

[0032] The invention is further based on the object of providing a method which can achieve high accuracies in cylinder machining.

[0033] This object is achieved by the method according to claim 11. In the method according to the invention, a blank is first picked up by the first workpiece clamping device and then machined externally by a tool clamped in a second tool holder. After the external machining of the workpiece, the workpiece is machined internally by a tool clamped in the first tool holder.

[0034] Alternatively, the workpiece can first be machined internally by the tool clamped in the first tool holder and then externally by the tool clamped in the second tool holder.

[0035] The workpiece is then transferred from a first workpiece clamping device to a second workpiece clamping device. The workpiece is then machined on a flat surface by the tool clamped in the third tool holder.

[0036] The limited linear and rotary movements of the first and second workpiece clamping devices as well as the first, second and third tool holders ensure high precision in the machining processes.

[0037] A method according to claim 12 enables high precision in the internal machining of the workpiece. For such machining, the ability to rotate the first tool holder about a tool axis running in the z-direction could be dispensed with. This could further increase the precision.

[0038] A method according to claim 13 increases the accuracy of internal machining.

[0039] A method according to claim 14 increases the accuracy of internal machining. Preferably, the first workpiece clamping device and the first tool holder are driven in opposite directions. This allows the desired speed for each rotary drive to be reduced. By reducing the required speed, this speed can be maintained and regulated more precisely. This results in improved accuracy during internal machining.

[0040] Alternatively, the first workpiece clamping device and the first tool holder can be driven in the same direction. This allows, for example, a slow rotation of one component to compensate for a fluctuation in the rotational speed of a fast-moving component. This allows a highly accurate cross-sectional image to be achieved.

[0041] Embodiments of the invention are explained in more detail below. They show: Fig. 1 a first embodiment of a machine tool according to the invention with a first tool holder with exactly one rotational degree of freedom and Fig. 2 a second embodiment of a machine tool according to the invention with a first tool holder without rotational degree of freedom.

[0042] The Fig. 1 shows a first embodiment of a machine tool 1 for the internal and external machining of sleeve-like workpieces 2. The machine tool 1 has a machine frame 3. Attached to the machine frame 3 are a workpiece slide 4, a first tool holder 7, a second tool holder 9, a second workpiece clamping device 10, a tool slide 12, as well as a feed device 15 arranged at the first end 14 of the machine frame 3 and a removal device 17 arranged at the second end 16 of the machine frame 3.

[0043] The workpiece carriage 4 comprises a first rotary spindle 5 and a first workpiece clamping device 6 with a rotational axis 32 running in the z-direction. The first tool holder 7 comprises a second rotary spindle 8 with a tool axis 35 running in the z-direction. The second workpiece clamping device 10 comprises a third rotary spindle 11 with a rotational axis 33 running in the z-direction. The tool carriage 12 comprises a third tool holder 13 with a tool axis 36 running in the x-direction. The second tool holder 9 has a tool axis 37 running in the x-direction. Raw parts 39 can be fed to the machine tool 1 by means of the feed device 15. Finished workpieces 40 can be removed by means of the removal device 17.

[0044] The tool carriage 4 and the tool carriage 12 are connected to the machine frame 3 via a rail 18. The workpiece carriage 4 and the tool carriage 12 can be moved in the x-direction along the rail 18 by means of threaded spindles 19, 20. Limit switches 21, 22 are arranged on the rail 18, by means of which the position of the workpiece carriage 4 and the tool carriage 13 can be zeroed.

[0045] The first rotary spindle 5 is movable in the z-direction on the workpiece carriage 4 via a drive (not shown). The first workpiece clamping device 6 is rotatably driven about the rotational axis 32 via the first rotary spindle 5. Consequently, a workpiece 2 clamped in the first workpiece clamping device 6 can also be rotated about the rotational axis 32 via the first rotary spindle 6. The first workpiece clamping device 6 is particularly designed such that it grips the workpiece 2 at a flat surface 23 of the workpiece 2, thereby enabling internal and external machining of the workpiece 2.

[0046] A tool 24 is accommodated in the first tool holder 7. The first tool holder 7 and thus the tool 24 can be driven in rotation about the tool axis 35 via the second rotary spindle 8. The tool 24 can be used to machine the inside of the workpiece 2. The first tool holder 7 is fixedly arranged on the machine frame 3. Linear movement along the x, y, or z direction is not possible. Likewise, the first tool holder 7 only has one degree of rotational freedom, namely around the z direction. Rotational movement around the x or y direction is not possible.

[0047] The second tool holder 9 comprises a tool changer 25 with a plurality of tools 26. The tools 26 can be changed by rotating the tool changer 25 around the tool axis 37. The second tool holder 9 is stationary on the machine frame 3; linear movement in the x, y, or z directions is not possible. Furthermore, the second tool holder 9 only has one rotational degree of freedom, namely rotation around the tool axis 37 in the form of the tool changer 25. Rotation around the y or z direction of the second tool holder 9 is not possible. Overall, the second tool holder 9 therefore has one degree of freedom. Alternatively, the second tool holder 9 can be designed without any degree of freedom by omitting the tool changer 25.

[0048] The second workpiece clamping device 10 can be driven in rotation about the rotation axis 33 via the third rotary spindle 11. The second workpiece clamping device 10 is designed such that it clamps the workpiece 2 via its inner diameter. The third rotary spindle 11 and thus the second workpiece clamping device 10 are fixedly arranged on the machine frame 3. Linear movement along the x-, y-, or z-direction is not possible. Likewise, the second workpiece clamping device 10 only has one degree of rotational freedom about the z-direction. Rotation about the x- or y-direction is not possible.

[0049] The third tool holder 13 comprises a tool changer 27 in which several tools 28 are arranged. The tools 28 can be changed by rotating the tool changer 27 about the tool axis 36.

[0050] The third tool holder 13 is movable in the z-direction on the workpiece carriage 12 by means of a drive (not shown). The third tool holder 13 thus has two linear degrees of freedom, namely in the x- and z-directions, as well as one degree of rotational freedom around the x-direction. Linear movement in the y-direction and rotational movements around the y- or z-direction are not possible.

[0051] A gripper 29 is arranged on the workpiece carriage 12. The gripper 29 is designed such that it can grip the workpiece 2 by a bead 30. The gripper 29, together with the third tool holder 13, is movable in the z-direction. Using the gripper 29, a finished workpiece 40 can be gripped by the bead 30 and then deposited on the removal device 17 by moving the workpiece carriage 12.

[0052] The machine tool 1 further has a transfer position 31, which is only indicated by a symbol. In the transfer position 31, the rotational axis 32 of the first workpiece clamping device 6 and the rotational axis 33 of the second workpiece clamping device 10 extend along the same straight line in the z-direction. At the transfer position 31, a workpiece 2 can be transferred from the first workpiece clamping device 6 to the second workpiece clamping device 10.

[0053] In the following, a machining sequence which is carried out using the machine tool 1 is explained in more detail.

[0054] Raw parts 39 are fed to the machine tool 1 via the feed device 15. The workpieces 2 are then picked up by the first workpiece clamping device 6 by a movement of the workpiece carriage 4 in the x-direction and the first workpiece clamping device 6 in the z-direction.

[0055] First, the workpiece 2 is moved to a first machining position (not shown). At the first machining position, the outer surface of the workpiece 2 is machined using the tool 26. The infeed is achieved by moving the workpiece carriage 4 in the x-direction. The feed is achieved by moving the first turning spindle 5 in the z-direction.

[0056] The workpiece 2 is then moved to a second machining position 34. In a second machining position 34, the workpiece carriage 4 is arranged above the first tool holder 7. In the first machining position 34, the rotation axis 32 and the tool axis 35 extend along the same straight line in the z-direction.

[0057] The inner surfaces of the workpiece 2 are machined by the tool 24 by means of a rotary movement. The feed is represented by a movement of the first rotary spindle 5 in the z-direction. The rotary movement can be achieved either by rotation of the workpiece 2 by the first rotary spindle 5 and / or by rotation of the tool 24 by the second rotary spindle 8. If a rotation of the first rotary spindle 5 and the second rotary spindle 8 is used simultaneously, the two rotary spindles 5, 8 preferably rotate in opposite directions.

[0058] Alternatively, the workpiece 2 can first be machined internally at a second machining position 34 and then the workpiece 2 can be machined externally at a first machining position.

[0059] After the internal and external machining of workpiece 2 has been completed, the workpiece carriage 4 moves to the transfer position 31. At the transfer position 31, the workpiece 2 is transferred from the first workpiece clamping device 6 to the second workpiece clamping device 10. The workpiece 2 is now located at a third machining position 38.

[0060] The flat surface 23 of the workpiece 2 is then machined by the tool 28. The machining of the flat surface 23 is performed by turning. The workpiece 2 is driven in rotation by the third turning spindle 11. The tool 28 is brought into the machining position by moving the workpiece slide 12 in the x-direction and the third tool holder 13 in the z-direction. Machining of the flat surface 23 of the workpiece 2 then begins by the tool 28, with the infeed movement of the tool 28 being performed by moving the third tool holder 13 in the z-direction. The feed for the flat surface machining is performed by moving the workpiece slide 12 in the x-direction.

[0061] After machining the flat surface 23 of the workpiece 2, the finished workpiece 40 is picked up by the gripper 29 and placed on the removal device 17 by a corresponding movement of the workpiece carriage 12. The finished workpiece 40 is then removed by the removal device 17 for transport or further processing.

[0062] The machine tool 1 can machine multiple workpieces 2 simultaneously. In particular, a first workpiece 2 can be machined on a first workpiece clamping device 6, while a second workpiece 2 is machined in a second workpiece clamping device 10. Alternatively, an entire machining process of a single workpiece 2 can take place before the next workpiece 2 is taken and machined.

[0063] The Fig. 2 shows a second embodiment of a machine tool 1 for internal and external machining of sleeve-like workpieces 2.

[0064] The structure and functionality of the machine frame 3, the workpiece carriage 4, the first workpiece clamping device 6, the second tool holder 9, the second workpiece clamping device 10, the tool carriage 12, the third tool holder 13, the feed device 15 and the removal device 17 correspond to the structure and functionality of the Fig. 1. The second embodiment differs from the first embodiment only with regard to the structure and functioning of the first tool holder 7.

[0065] The first tool holder 7 of the Fig. The second exemplary embodiment of the machine tool 1 shown in Figure 2 is fixed in position and secured against rotation to the machine frame 3 via a tool carrier plate 41. The first tool holder 7 cannot be moved or rotated, in particular during operation of the machine tool 1. When the machine tool 1 is at a standstill, the first tool holder 7 can be displaced in its position on the tool carrier plate 41, in particular using a suitable tool.

[0066] The tool carrier plate 41 can be detachably or permanently connected to the machine frame 3. Preferably, the tool carrier plate 41 is attached to the machine frame 3 via a screw connection. The first tool holder 7 can be detachably or permanently connected to the tool carrier plate 41. Preferably, the first tool holder 7 is detachably connected to the tool carrier plate 41.

[0067] The first tool holder 7 of the Fig. The second embodiment of the machine tool 1 shown in Figure 2 has a tool axis 42 extending in the z-direction. In this embodiment, the first tool holder 7 is secured against rotation and cannot be driven in rotation about the tool axis 42.

[0068] The rotationally secured first tool holder 7 generates the relative rotational movement in the first machining position 34 by the first workpiece clamping device. The rotationally secured first tool holder 7 allows the manufacturing accuracy to be increased compared to the Fig. 1 shown first embodiment can be further increased. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2009 009 969 B4

[0002]

Claims

[1] Machine tool (1), in particular for machining bush-like or sleeve-like workpieces (2), comprising - a machine frame (3), - a workpiece carriage (4) movable in an x-direction, - a first workpiece clamping device (6) -- which is arranged on the workpiece carriage (4) so as to be movable in a z-direction, -- which can be driven in rotation about an axis of rotation (32) running in the z-direction, - a stationary second workpiece clamping device (10) arranged on the machine frame (3), -- which is rotatably driven about an axis (33) running in the z-direction, - a stationary first tool holder (7) arranged on the machine frame (3) for internal machining of a workpiece (2) clamped in the first workpiece clamping device (6), - a stationary second tool holder (9) arranged on the machine frame (3) for external machining of a workpiece (2) arranged in the first workpiece clamping device (6), - a tool carriage (12) movable in an x-direction, which -- a third tool holder (13) movable in the x-direction for external machining of a workpiece (2) clamped in the second workpiece clamping device (10), characterized by , that the third tool holder (13) has exactly one degree of rotational freedom and can be driven in rotation about a tool axis (36) running in the x-direction, and / or that the first tool holder (7) has at most one rotational degree of freedom and can be driven in rotation about at most one tool axis (35) running in the z-direction. [2] Machine tool (1) according to claim 1, characterized bythat the third tool holder (13) includes a tool changing function. [3] Machine tool (1) according to one of claims 1 or 2, characterized by that the second tool holder (9) has exactly one rotational degree of freedom. [4] Machine tool (1) according to one of the preceding claims, characterized by that the second tool holder (9) can be driven in rotation about a tool axis (37) running in the x-direction. [5] Machine tool (1) according to one of the preceding claims, characterized by that the second tool holder (9) includes a tool changing function. [6] Machine tool (1) according to one of the preceding claims, characterized by a feeding device (15) for raw parts (39) to be machined, arranged at a first end (14) of the machine frame (3). [7] Machine tool (1) according to one of the preceding claims, characterized by a removal device (17) for finished workpieces (40) arranged at a second end (16) of the machine frame (3). [8] Machine tool (1) according to one of the preceding claims, characterized by that a rotational axis (32) of the first workpiece clamping device (6) and a rotational axis (33) of the second workpiece clamping device (10) lie on a straight line running in the z-direction at a transfer position (31). [9] Machine tool (1) according to one of the preceding claims, characterized by that the first tool holder (7) has exactly one rotational degree of freedom and can be driven in rotation about a tool axis (35) running in the z-direction. [10] Machine tool (1) according to one of the preceding claims, characterized by that the first tool holder (7) has no rotational degree of freedom. [11] Method for producing a bush-like or sleeve-like workpiece (2), comprising the steps: - Providing a machine tool (1) according to at least one of claims 1 to 10, - clamping a workpiece (2) in the first workpiece clamping device (6), - external machining of the workpiece (2) by means of a tool (26) clamped in the second tool holder (9), -- wherein the workpiece (2) is driven in rotation by the first workpiece clamping device (6) and the second tool holder (9) remains rigid and -- wherein the machining feed is effected by a movement of the first workpiece clamping device (6) in the z-direction, - internal machining of the workpiece (2) by means of a tool (24) clamped in the first tool holder (7), -- wherein the machining feed is effected by a movement of the first workpiece clamping device (6) in the z-direction and -- wherein the first workpiece clamping device (6) and the first tool holder (7) perform a relative rotational movement, - transfer of the workpiece (2) from the first workpiece clamping device (6) to the second workpiece clamping device (10), - external machining of the workpiece (2) by means of a tool (28) clamped in the third tool holder (13), -- wherein the machining feed is effected by a movement of the third tool holder (13) in the x-direction and / or the z-direction, -- wherein the workpiece (2) is rotationally driven by the second workpiece clamping device (10) and the third tool holder (13) is moved only in linear degrees of freedom. [12] Method according to claim 11, characterized by that the relative rotational movement is generated by the first workpiece clamping device (6) being driven in rotation and tools (24) clamped in the first tool holder (7) being stationary. [13] Method according to one of claims 11 or 12, characterized by that the relative rotational movement is generated in that the first workpiece clamping device (6) is stationary and the tool (24) clamped in the first tool holder (7) is driven in rotation. [14] Method according to one of claims 11 to 13, characterized by that the relative rotational movement is generated by the first workpiece clamping device (6) and the tool (24) clamped in the first tool holder (7) being driven in rotation.

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