Method for turning a workpiece by laser light guided by a fluid jet

Abstract

The present disclosure relates to turning a workpiece with a laser beam coupled to a fluid jet, i.e., guided by the fluid jet. The present disclosure provides a method (20) and an apparatus (10), respectively, for machining a workpiece, the machining including turning the workpiece. The method is performed by an apparatus (10) configured to provide a laser beam (12) guided by a fluid jet (11). The method includes turning the workpiece (30), the turning including rotating the workpiece about an axis of rotation (31) during machining and applying the laser beam guided by the fluid jet to a machining surface (32) of the workpiece.

Description

Technical Field

[0001] The present disclosure relates to the field of machining workpieces, and in particular, to machining workpieces by turning. In particular, the present disclosure relates to turning a workpiece using a laser beam coupled to a fluid jet, i.e., a laser beam guided by a fluid jet. The present disclosure provides a method and an apparatus for machining a workpiece, respectively, the machining including turning the workpiece. The method may be implemented by the apparatus, and the apparatus is configured to provide a laser beam guided by a fluid jet.

Background Art

[0002] Turning is a process of machining a workpiece, which, for example, consists of cutting into the workpiece using a cutting tool while the workpiece is rotating. Thereby, the cutting tool moves linearly while the workpiece is rotating, for example, such that the cutting tool traces a helical path on the workpiece surface. That is, conventional turning of a workpiece consists of rotating the workpiece around a rotation axis while machining the workpiece, for example, cutting with a cutting tool. The turning speed of the workpiece is determined by the rotational speed at which the workpiece is rotated. The conventional cutting tool may be a conventional type of laser.

Summary of the Invention

Problems to be Solved by the Invention

[0003] Conventional turning has several drawbacks. For example, not all materials can be easily turned using conventional methods, i.e., conventional cutting tools. There are materials that are too hard for cutting tools, such as diamond and superalloys, and there are also materials that are too brittle, like PHYNOX or MAGIC GOLD, or are weak against the heat generated from the cutting tool during turning of the workpiece. Furthermore, there are generally limitations on the size of the workpiece that can still be achieved for turning the workpiece. Specifically, workpieces with a high aspect ratio are difficult to machine by conventional turning. Additionally, larger workpieces (having a larger volume and / or diameter) may be very difficult to machine by conventional laser turning. Finally, the surface roughness of the machined surface of the turned workpiece is often unsatisfactory after conventional turning, i.e., the surface is often too rough and further processing steps such as polishing are required.

[0004] Another drawback of conventional turning is that this machining process cannot be easily incorporated into a machining flow that also includes other machining processes of the workpiece, such as drilling, milling, or engraving of the workpiece (especially the turned workpiece).

[0005] Accordingly, embodiments of the present invention aim to improve the conventional method of machining a workpiece by turning. The aims are, in particular, to provide a method and an apparatus, respectively, that can turn workpieces of many types of materials, even those that are very hard and / or brittle or weak against heat. The turning is preferably performed fully automatically. Furthermore, it is easy to integrate the turning with one or more other machining processes of the workpiece. The turning further brings about an improvement in the surface roughness of the machined surface of the machined workpiece. Additionally, it is fully possible to perform turning on larger workpieces. Finally, the process time for machining a workpiece with a predetermined accuracy, quality, and shape is shortened, and at the same time, the tool consumption during the machining process is also reduced. Embodiments of the present invention also enable machining of a new type of workpiece, such as machining a high aspect ratio groove in a workpiece made of a hard and brittle and / or heat-weak material.

Means for Solving the Problems

[0006] These objects and other objects are achieved by the embodiments defined in the independent claims of the present application. Advantageous implementations of these embodiments are defined in the dependent claims.

[0007] In particular, embodiments of the present invention generally are based on the use of an apparatus for implementing a method for machining a workpiece, which method consists of turning the workpiece. This apparatus provides laser light guided within a fluid jet by internal reflection. The laser light guided by this fluid jet can efficiently turn the workpiece. Thereby, according to embodiments of the present invention, different orientations between the laser light and the machining surface of the workpiece are possible. By these embodiments, even workpieces made of superhard materials or brittle or heat-sensitive materials can be turned with very high precision, especially for high aspect ratios or complex shapes.

[0008] A first aspect provides a method for machining a workpiece, the method being implemented by an apparatus that provides laser light guided by a fluid jet, the method including turning the workpiece, and turning the workpiece including rotating the workpiece around a rotation axis during machining and irradiating a machining surface of the workpiece with laser light guided by a fluid jet.

[0009] The workpiece rotates continuously during turning, especially during machining of the workpiece. The laser light guided by the fluid jet enables turning of workpieces made of many types of materials, including very hard materials, brittle or very heat-sensitive materials. With this apparatus, turning can be performed fully automatically. Compared with conventional turning methods that do not use laser light guided by a fluid jet, the method of the first aspect achieves improved results in turning the workpiece. For example, improvements in terms of speed, accuracy, and surface roughness, or reachability of the fluid jet.

[0010] The workpiece may have a regular shape such as a cylindrical shape with a certain diameter. Turning of the workpiece may form one or more cylindrical surfaces of such a workpiece, and the one or more cylindrical surfaces may have a reduced diameter. Generally, any rotational shape is achievable. Turning may also form one or more surfaces that are oriented mainly perpendicular to the axis of the workpiece, which may be called facing by turning. Turning can also form one or more grooves on the outer surface of the workpiece, i.e., grooves in the circumferential direction with respect to the diameter of the workpiece, which may be called grooving by turning. Turning can also form one or more grooves on the end face of the workpiece, i.e., grooves around the axis of rotation, which may be called boring. The workpiece can also have an irregular shape, for example, having a radius that varies continuously along the axis of rotation or having a helical shape. The workpiece with an irregular shape before machining may be pre-machined into a workpiece with a more regular shape by, for example, facetting as further described below.

[0011] In the implementation of the method, the laser beam guided by the fluid jet is irradiated perpendicular to the machining surface, or in a tangential direction with respect to the machining surface, or in a substantially tangential direction with respect to the machining surface.

[0012] Therefore, different orientations between the laser beam and the machining surface are possible, which enables different application scenarios. For example, the perpendicular direction results in a higher material removal rate and is thus beneficial for machining larger workpieces, while the tangential direction enables higher precision, higher surface quality, and less stress generation in the workpiece. In the case of the tangential direction, the nozzle axis (the nozzle axis of the fluid generation nozzle for generating the fluid jet within the device coincides with the propagation direction of the fluid jet) is in contact with the machining surface of the workpiece. Note that when a 6-axis device is used, the angle between the laser beam and the machining surface is arbitrary.

[0013] In the implementation of the method, the axis of rotation is perpendicular to the propagation direction of the laser beam guided by the fluid jet provided by the device.

[0014] In the implementation of this method, the propagation direction of the laser beam guided by the fluid jet does not intersect the rotation axis.

[0015] For example, the propagation direction of the laser beam guided by the fluid jet is perpendicular to the rotation axis but offset from the rotation axis. That is, the shortest connection between the rotation axis and the machining surface is oblique with respect to the propagation direction of the laser beam guided by the fluid jet, and for example, also oblique with respect to the vertical direction.

[0016] In the implementation of this method, the laser beam guided by the fluid jet is irradiated obliquely with respect to the machining surface.

[0017] This angle is, for example, between 90° (in this case, the laser beam guided by the fluid jet is irradiated perpendicular to the machining surface) and 0° (in this case, the laser beam guided by the fluid jet is irradiated tangentially to the machining surface).

[0018] When the workpiece is machined with the laser beam guided by the fluid jet according to the method of the first aspect, in the above implementation, the radius of the workpiece decreases. As a result, the angle at which the laser beam guided by the fluid jet irradiates the machining surface also decreases accordingly, and the laser beam guided by the fluid jet irradiates the machining surface until it irradiates the machining surface tangentially. This advantage means that the machining of the workpiece automatically changes from rough machining with a high material removal rate (MRR) from the machining surface to smooth machining (smoothing) for surface finishing of the machining surface.

[0019] Furthermore, when the laser beam guided by the fluid jet is moved along a predetermined profile, the offset of its propagation direction with respect to the rotation axis changes, and as a result, the angle at which the laser beam guided by the fluid jet irradiates the machining surface also changes. For example, when the propagation direction of the laser beam guided by the fluid jet is close to the rotation axis, the angle is large (approaching 90°), and the throughput and MRR increase. Accordingly, since the profile path guides the laser beam guided by the fluid jet closer to the rotation axis, the amount of material to be removed can increase. Thus, in the method of the first aspect, a functional machining strategy can be applied, which provides a high throughput for regions with a large amount of material to be removed while finishing the region close to the outer diameter of the workpiece in a smooth manner without changing the parameters.

[0020] In the implementation of the present method, the method further includes moving the laser beam guided by the fluid jet along the moving direction while turning the workpiece.

[0021] Therefore, the laser beam can move along a determined path on the workpiece surface, for example, it can draw a spiral path. Therefore, different shapes of the workpiece by turning can be realized. In particular, the laser beam can be moved by relatively displacing the workpiece and the laser beam with respect to each other. That is, in order to realize the effective movement of the laser beam, the workpiece may be moved, or the workpiece and the laser beam may be moved. The laser beam and / or the workpiece may be linearly displaced simultaneously or continuously along two or three axes. Furthermore, it is also possible to rotate the workpiece around two or three different rotation axes during machining. The rotation of the workpiece around one or more rotation axes can be synchronized with the linear displacement of the workpiece and / or the laser beam along one or more axes.

[0022] The fluid jet can accordingly move over the workpiece. In one embodiment, the fluid jet can perform a multi-pass movement on the workpiece. The multi-pass movement is mainly brought about by the rotation of the workpiece.

[0023] In the implementation of this method, the moving direction is parallel or perpendicular to the rotation axis and perpendicular to the propagation direction of the laser beam guided by the fluid jet.

[0024] In the implementation of this method, the rotation axis is parallel to the laser beam guided by the fluid jet.

[0025] In the implementation of this method, the laser beam is pulsed, and the rotational speed for rotating the workpiece around the rotation axis is set such that at least 50% of the consecutive pulses of the pulsed laser beam overlap each other on the processed surface of the workpiece.

[0026] That is, the laser beam can draw a continuous path on the processed surface of the workpiece. An overlap of 50% or more of the pulsed laser beam results in efficient processing of the workpiece, particularly a low surface roughness of the processed surface of the processed workpiece.

[0027] In the implementation of this method, the laser beam is pulsed, and the pulsed laser beam includes at least two overlapped pulses selected based on a specific material of the workpiece, and the first pulse has a different power and frequency from the second pulse.

[0028] In other words, for a single material of the workpiece processed using the method of the first aspect, at least two pulses can be selected and combined to form a composite pulsed laser beam. Each laser pulse gives a specific, particularly regular pulse shape in the composite pulsed laser beam, that is, at least a first laser pulse shape having a first laser power and a first laser frequency and a second laser pulse shape having a second laser power and a second laser frequency. The two laser powers and laser frequencies overlap. Thus, the composite pulsed laser beam can exhibit a beating pattern.

[0029] Primarily, this method is designated for machining a workpiece made from a solid block of one type of material (i.e., a specific material) and using at least two pulses to machine this specific material by turning. However, this method can also be applied to workpieces containing two or more materials, for example, workpieces made of layers of different materials. In this case, each layer is ideally machined individually by using at least two pulses per layer. When two such layers are machined simultaneously, preferably a plurality of pulses are selected, especially at least two pulses are selected for each layer.

[0030] The first pulse of the pulsed laser light is generated, for example, by dominant / master laser emission output by a first laser light source, and the second pulse is generated by slave laser emission output by a second laser light source, for example. Each laser light source is configured to output simple pulsed laser light having a determined power (absolute peak power and / or pulse width) and frequency (pulse repetition rate). For example, the dominant / master laser emission is selected such that the specific material to be machined exhibits strong absorption of the laser light and / or has a higher intensity than the slave laser emission, and the slave laser emission is selected such that the specific material exhibits weak absorption of the laser light and / or has a lower intensity than the dominant laser emission. However, the effects related to the master / slave laser emission described herein are not necessarily defined in accordance with the names of the "first" and "second" pulses in this application. The selection of the power and frequency of each laser pulse may be based on (dependent on) the frequency-dependent absorption coefficient of the specific material to be machined. In other words, a specific material may absorb differently with different laser oscillation wavelengths and pulse characteristics. It should be noted that there may also be cases where two overlapping laser pulses are generated by a single dedicated laser light source.

[0031] The composite pulsed laser light can be configured to create ablation of the material of the workpiece, and the ablated surface remains very homogeneous. In particular, by selecting at least two pulses according to the specific material of the workpiece to be processed, a very low surface roughness and a surface quality with little or no variation can be achieved. Furthermore, the occurrence of defects and chips can be significantly reduced or even completely suppressed. Therefore, the processing of workpieces, especially those made of hard and / or brittle materials, is improved.

[0032] In the implementation of this method, the first pulse is suitable for cutting the specific material of the workpiece, and the second pulse is not suitable for cutting the specific material of the workpiece and / or is suitable for smoothing the surface of the specific material of the workpiece, for example, smoothing the surface formed by cutting the specific material with the first pulse.

[0033] This means that the first pulse of the pulsed laser light (e.g., dominant laser emission) used alone already cuts / ablates the material of the workpiece, but cuts / ablates it with relatively poor surface quality. The second pulse (second pulsed laser emission) used alone cannot cut / ablate the workpiece material, but can only smooth or polish the surface of the workpiece material. The ability of such two-laser-pulse emissions depends on their respective characteristics, especially their respective power and frequency. These characteristics are selected based on the type of material of the workpiece to be processed. When at least two laser pulses are overlapped in the pulsed laser light used by the method of the first aspect, they cooperate to process the workpiece with improved surface quality. This can lead to a fairly low surface roughness. Furthermore, defects and chips of the material can be almost avoided.

[0034] In the implementation of this method, the method further includes facetting the workpiece before turning the workpiece, and facetting the workpiece includes separating a series of portions from the workpiece with a laser beam guided by a fluid jet to reduce the diameter of the workpiece relative to the axis of rotation.

[0035] Facetting can help quickly reduce the size of larger workpieces to speed up the entire machining process of the workpiece, including turning. Facetting can in particular reduce the diameter of the workpiece and enable subsequent turning to be carried out efficiently and with high precision.

[0036] In particular, the diameter of the workpiece can vary along the workpiece (e.g., along the main axis of rotation for turning). By performing facetting on such a workpiece before turning, it can be cut into a controlled shape, and as a result, the post-turning results can be improved. Furthermore, facetting may make it possible to obtain various shapes of the machined workpiece, such as shapes including spheres or hemispheres.

[0037] In the implementation of this method, separating a portion from the workpiece includes cutting into the workpiece with a laser beam guided by a fluid jet, rotating the workpiece by an angle around the axis of rotation, and cutting into the workpiece again with a laser beam guided by a fluid jet to separate a portion from the workpiece.

[0038] The first cut into the workpiece may include partially cutting into the thickness of the workpiece. It should be noted that one or more portions of the workpiece can also be cut off / separated from the workpiece with one cut instead of two cuts and the rotation of the workpiece therebetween.

[0039] In the implementation of this method, partially cutting the workpiece involves separating a first subset, which is a part of the workpiece, at an angle that is larger, reducing the diameter of the workpiece with respect to the axis of rotation, and separating a second subset, which is a part of the workpiece, at an angle that is smaller, further reducing the diameter of the workpiece with respect to the axis of rotation.

[0040] Thus, in the partial cutting with a large angle, the shape of the workpiece becomes rough, but the partial cutting is performed at high speed, and in the subsequent partial cutting with a small angle, the shape of the workpiece can be made smoother. As a result, the process time can be shortened.

[0041] In the implementation of this method, the method further includes executing an optimization algorithm regarding the surface finish of the machined workpiece and / or the process time for machining the workpiece based on the size and / or shape of the workpiece, and performing partial cutting and turning of the workpiece based on the result of the optimization algorithm.

[0042] The optimization algorithm can select a partial cutting plan, that is, how to partially cut the workpiece. The constraints considered by the optimization algorithm include the maximum diameter or volume of the workpiece (typically, before partial cutting) and the minimum diameter or volume of the workpiece (typically, desired after subsequent turning). The optimization algorithm can, in particular, determine at least one of how many parts to separate from the workpiece, how many surfaces to form, what specific angle to use in partial cutting, whether to separate the first subset and the second subset as described above, the difference between the first specific angle and the second specific angle, from which side to cut into the workpiece (e.g., determine for each cut), which laser output to use for each cut, and how fast to turn the workpiece after partial cutting.

[0043] In the implementation of this method, the material of the workpiece includes at least one of diamond, diamond composite material, polycrystalline diamond, polycrystalline boron nitride, silicon carbide, superalloy, ceramic, finox, titanium, titanium alloy, cobalt alloy, and composite materials containing each of the aforementioned materials.

[0044] Therefore, workpieces made of many types of materials can be turned, such as (very) hard materials, (very) brittle materials, heat-sensitive materials, or compliant and / or soft materials.

[0045] In the implementation of this method, in addition to turning the workpiece, this method further includes at least one of cutting straight and deeply into the workpiece, drilling a hole in the workpiece, engraving the workpiece, and laser milling the workpiece using a laser beam guided by a fluid jet.

[0046] In the implementation of this method, this method is automatically and / or continuously executed by a device, and / or this method is executed by a device in a single process.

[0047] In the implementation of this method, the arithmetic mean roughness of the machined surface of the machined workpiece is 0.4 μm or less.

[0048] In particular, the arithmetic mean roughness may be 0.2 μm or less. In the implementation of this method, the diameter of the workpiece is greater than 30 mm. For example, the diameter of the workpiece may be 125 mm or more.

[0049] Therefore, compared to turning with a laser without using a fluid jet, especially in the case of tangential irradiation, it is fully possible to perform turning on a larger workpiece (larger diameter and / or volume) using the method of the first aspect. It should be noted that the workpiece may have, for example, a regular cylindrical shape with a constant and clearly defined diameter, or a shape such as a sphere. However, the workpiece may also have an irregular shape and / or a diameter that varies along the turning axis. In this case, the diameter may refer to the largest diameter measurable for the workpiece. The diameter is measured as the distance from one workpiece surface (e.g., the machined surface) to the opposite workpiece surface. The diameter of the workpiece may be as generally understood by those skilled in the art of this technical field.

[0050] The second aspect provides an apparatus for machining a workpiece, the apparatus comprising a machining unit configured to provide laser light guided by a fluid jet, a holder configured to hold and rotate the workpiece, and a control unit configured to control the machining unit and the holder respectively, rotate the workpiece around the rotation axis during machining to perform turning on the workpiece, and irradiate the machining surface of the workpiece with laser light guided by a fluid jet.

[0051] In the implementation of this apparatus, the apparatus is configured to rotate the holder to rotate the workpiece around two or three different rotation axes, linearly displace the workpiece along two or three axes, and / or the control unit is configured to control the holder to synchronize the rotation of the workpiece around one or more rotation axes and the linear displacement of the workpiece along one or more axes.

[0052] The apparatus of the second aspect provides all the advantages described above for the method of the first aspect and can be implemented in the same way. That is, in an embodiment of the apparatus, the apparatus may be configured according to the embodiment of the method described above.

[0053] The device can perform, in particular, the machining of a workpiece, including turning the workpiece, and optionally further machining of the workpiece, continuously, and / or automatically, and / or in a single process.

[0054] A third aspect provides a computer program comprising any program code for controlling the device according to the second aspect or for executing the method according to the first aspect when executed by a processor, in particular a processor of a control unit.

[0055] A fourth aspect of the present disclosure provides a non-transitory storage medium storing executable program code that, when executed by a processor, causes the processor to execute the method according to the first aspect or an implementation thereof.

[0056] The above aspects and embodiments defining general embodiments according to the present invention are described in the following description of specific embodiments related to the accompanying drawings, in which they are described as follows. BRIEF DESCRIPTION OF THE DRAWINGS

[0057]

Figure 1

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DETAILED DESCRIPTION OF THE INVENTION

[0058] FIG. 1 schematically shows a method 20 according to an embodiment of the present invention. Each step of the method 20 is additionally shown in the flowchart of FIG. 2. The method 20 is suitable for machining a workpiece 30, and the method 20 consists of turning the workpiece 30 with a laser beam 12 guided by a fluid jet 11.

[0059] Method 20 is implemented by an apparatus 10 according to an embodiment of the present invention, as schematically shown also in FIG. 1 or as shown with more optional details in FIG. 10. The apparatus 10 is configured to provide a laser beam 12 coupled to a (pressurized) fluid jet 11, i.e., to irradiate a workpiece 30 with the laser beam 12 guided by the fluid jet 11. Accordingly, the fluid jet 11 may be composed of a liquid jet, and in particular, may be composed of a water jet.

[0060] The material of the workpiece 30 may include at least one of diamond, diamond composite, polycrystalline diamond, polycrystalline boron nitride, silicon carbide, superalloy, ceramic, finox, magic gold, titanium, titanium alloy, cobalt alloy, and one or more composite materials including these materials. The workpiece 30 can have any volume or diameter. In particular, the workpiece may have a diameter greater than 20 mm, greater than 30 mm, or even greater than 50 mm, or even greater than 100 mm, or even greater than 125 mm.

[0061] Method 20 consists of turning (21, 22) the workpiece 30. Turning (21, 22) of the workpiece 30 includes the step of rotating 21 the workpiece 30 around a rotation axis 31 during machining. The workpiece 30 may be continuously rotated around the rotation axis 31 during turning (21, 22) of the workpiece 30. The workpiece 30 may further be rotated around one or more additional rotation axes during turning (21, 22), or more generally, during machining of the workpiece 30. Further, turning (21, 22) includes the step of irradiating 22 the machining surface 32 of the workpiece 30 with the laser beam 12 guided by the fluid jet 11. The laser beam 12 guided by the fluid jet 11 may be irradiated perpendicularly onto the machining surface 32 (as exemplarily shown in FIG. 1), or may be irradiated tangentially or substantially tangentially to the machining surface 32, as further described below with respect to FIGS. 4 to 7.

[0062] Figure 3 shows different examples of method 20 according to an embodiment of the present invention, based on the embodiment shown in Figure 1. In particular, Figure 3 shows, in (a) and (b), different examples of irradiating the processing surface 32 of the workpiece 30 with the laser beam 12 guided by the fluid jet 11. The same elements in Figures 1 and 2 in Figure 3 are assigned the same reference numerals and are implemented in the same manner.

[0063] In Figure 3(a), the laser beam 12 guided by the fluid jet 11 is irradiated perpendicularly onto the processing surface 32 of the workpiece 30. That is, the propagation direction of the laser beam 12 guided by the fluid jet 11 is perpendicular to the plane in which the processing surface 32 lies. In Figure 3(b), the laser beam 12 guided by the fluid jet 11 is irradiated in the tangential direction of the processing surface 32 of the workpiece 30. That is, the propagation direction of the laser beam 12 guided by the fluid jet 11 is parallel to the processing surface 32 and in contact with the processing surface 32. In both cases shown in Figure 3, the rotation axis 31 about which the workpiece 30 is rotated at least 21 during turning (21, 22) is, by way of example, perpendicular to the propagation direction of the laser beam 12 guided by the fluid jet 11.

[0064] The power of the laser beam 12, or the pulse characteristics of the pulsed laser beam 12 (i.e., pulse width, pulse rate, pulse burst rate, pulse power, etc.) may vary for machining, particularly turning (21, 22), between a first case (first pulse) where the laser beam 12 is irradiated perpendicular to the machining surface 32 and a second case (second pulse) where the laser beam 12 is irradiated in a tangential direction to the machining surface 32. In the first case, the perpendicular laser beam 12 may result in a higher workpiece material removal rate, and thus may be beneficial for turning (21, 22) a larger workpiece 30 (e.g., having a large volume and / or a diameter of 30 mm or more). In the second case, it may be beneficial for turning the workpiece 30 (21, 22) when improved accuracy and workpiece surface are required, and when reduction of stress generation in the workpiece 30 during machining is necessary. It should be noted that the second case, where the laser beam 12 is provided in a tangential direction to the machining surface 32, is only achievable due to the fact that the laser beam 12 is guided within the fluid jet 11. Such orientation cannot be fully achieved with a laser beam without fluid injection, because with such a laser, neither a long parallel focus nor sufficient coupling of the laser power to the surface of the workpiece can be obtained.

[0065] Figures 4 to 7 each show different examples of a method 20 according to an embodiment of the present invention, based on the embodiments shown in Figures 1 and 2. In particular, different examples are shown of irradiating the machining surface 32 of the workpiece 30 with the laser beam 12 guided by the fluid jet 11 (Figures 5 to 7) and moving the laser beam 12 guided by the fluid jet 11 relative to the workpiece 30 during turning (21, 22) of the workpiece 30 (Figure 4). The same elements in Figures 4 to 7 and Figures 1 to 3 are labeled with the same reference numerals and are implemented in the same manner.

[0066] In particular, in FIG. 4(a), two directions of the laser beam 12 guided by the fluid jet 11 with respect to the machined surface 32, which have already been shown in FIG. 3, are shown. However, FIG. 4(a) additionally shows that during turning (21, 22), the laser beam 12 guided by the fluid jet 11 can be moved parallel to the rotation axis 31. It should be noted that the moving direction shown in FIG. 4(a) is, by way of example, perpendicular to the propagation direction of the laser beam 12. Thereby, as also shown in FIG. 4(a), for example, by turning (21, 22) the workpiece 30, the diameter of a part of the workpiece 30 can be reduced.

[0067] FIG. 4 further shows in (b) two directions of the laser beam 12 guided by the fluid jet 11 with respect to the machined surface 32, which have already been shown in FIG. 3. However, FIG. 4(b) additionally shows that during turning (21, 22), the laser beam 12 guided by the fluid jet 11 can be moved perpendicular to the rotation axis 31. However, in contrast to FIG. 4(a) where it is shown that the laser beam 12 moves perpendicular to the diameter of the workpiece 30, in FIG. 4(b) it is shown that the laser beam 12 moves in the radial direction of the workpiece 30. The procedure shown in FIG. 4(b) is particularly useful when forming a surface or a groove on the workpiece 30 by turning (21, 22).

[0068] For the machining of the workpiece 30, the moving directions shown in FIGS. 4(a) and (b) can be added to each other or carried out simultaneously.

[0069] Figure 4 further shows in (c) that the rotation axis 31 can also be parallel to the propagation direction of the laser beam 12 guided by the fluid jet 11. In this case, as exemplarily shown in Figure 4(c), the laser beam 12 can cut a circular groove into the end face of the workpiece 30. The laser beam 12 can further be moved, for example, perpendicular to the rotation axis 31 in order to widen the circular groove. The procedure shown in Figure 4(c) is particularly useful for drilling a hole in the workpiece 30 by turning (21, 22). Complex pocketing cinematics can be applied to effect the movement of the laser beam 12.

[0070] In each of the cases (a), (b), and (c) shown in Figure 4, in order to create a more complex shape of the workpiece 30 to be machined, for example, during machining of the workpiece 30, specifically during turning (21, 22) of the workpiece 30, it is possible for the workpiece 30 to be further rotated about another rotation axis. This becomes possible by combining with one or more movement directions of the laser beam 12 during machining, specifically during turning (21, 22) of the workpiece 30.

[0071] Figure 5(a) shows the case where the laser beam 12 guided by the fluid jet 11, as described above, is irradiated in the tangential direction of the machining surface 32 of the workpiece 30. Here, in Figure 5(a), the propagation direction of the laser beam 12 guided by the fluid jet 11 is perpendicular to the rotation axis 31 (running in the plane of Figure 5). Further, the laser beam 12 guided by the fluid jet 11 propagates along the vertical direction (the direction running from top to bottom in Figure 5(a)), that is, the angle β between the propagation direction of the laser beam 12 and the vertical direction (or generally the reference direction) is 0°. The laser beam 12 further contacts the tangential direction of the machining surface 32 such that the angle α between the shortest connection part (between the rotation axis 31 and the machining surface 32) and the vertical direction is 90°.

[0072] FIG. 5(b) shows the aforementioned case where the laser beam 12 guided by the fluid jet 11 is irradiated perpendicularly to the machining surface 32. Here, in FIG. 5(b), the propagation direction of the laser beam 12 guided by the fluid jet 11 is again a direction perpendicular to the rotation axis 31. Further, the laser beam 12 guided by the fluid jet 11 propagates along the vertical direction (reference direction) such that the angle β is 0°. The angle α is, in this case, 0°, that is, the shortest connection (between the rotation axis 31 and the machining surface 32) is along the vertical direction.

[0073] FIG. 6(a) shows that different angles (values) are possible for the angle α. For example, the laser beam 12 guided by the fluid jet 11 may be irradiated along the vertical direction, that is, in a state where the angle β is 0°, but may also be offset with respect to the position in FIG. 5(b), that is, irradiated without the propagation direction of the laser beam 12 intersecting the rotation axis 31. That is, the angle α may be greater than 0° and less than 90°. This also means that the laser beam 12 guided by the fluid jet 11 is obliquely irradiated on the machining surface 32, the angle is 0° or more and 90° or less, and the angle at which the laser beam 12 guided by the fluid jet is irradiated on the machining surface 32 is (90° - α).

[0074] FIG. 6(b) further shows that different angles (values) are also possible for the angle β. For example, the laser beam 12 guided by the fluid jet 11 may be inclined with respect to the vertical direction, that is, the angle β may be greater than 0° and less than 90°. For example, the angle β may be equal to the angle α that is illustratively greater than 0° and less than 90° in FIG. 6(b).

[0075] Figure 7 shows the advantages of the configuration shown in Figure 6, particularly the advantages over the configuration shown in Figure 6(a), from (a) to (d). The propagation direction of the laser beam 12 guided by the fluid jet 11 is perpendicular to the rotation axis 31 but does not intersect the rotation axis 31. That is, as shown in Figure 6(a), the propagation direction is offset from the rotation axis 31 such that the angle α satisfies 0° < α < 90°. In Figure 7(a), the angle is particularly α = α1. When the workpiece is turned according to method 20, as shown in Figure 7(b), Figure 7(c), and finally Figure 7(d), its radius continuously decreases. Accordingly, as also shown, the angle α increases. In Figure 7(b), the angle is particularly α = α2, in Figure 7(c), the angle is particularly α = α3, and in Figure 7(d), the angle is particularly α = α4, where α4 > α3 > α2 > α1. At the same time, the angle at which the laser beam 12 guided by the fluid jet 11 is irradiated onto the machining surface 32 (calculated as 90° - α) also decreases. In Figure 7(a), this angle is close to 90° (i.e., close to the configuration in which the laser beam 12 guided by the fluid jet 11 is perpendicularly irradiated onto the machining surface 32 as shown in Figure 5(b)), and in Figure 7(d), this angle is close to 0° (i.e., close to the configuration in which the laser beam 12 guided by the fluid jet 11 is irradiated onto the machining surface 32 in a tangential direction as shown in Figure 5(a)). Since the angle at which the laser beam 12 guided by the fluid jet 11 is irradiated onto the machining surface 32 decreases (and / or since α increases), the machining process gradually changes from rough machining with a high material removal rate of the machining surface 32 of the workpiece 30 to finish machining.

[0076] Figure 8 shows further advantages of the method and configuration described with respect to Figure 7. In particular, Figure 8(a) shows moving the laser beam 12 guided by the fluid jet 11 along a predetermined profile path 70 in order to machine the workpiece 30 into a product having a target shape that is, for example, as complex as that shown in Figure 8(b). Thereby, the distance between the propagation direction of the laser beam 12 guided by the fluid jet 11 and the rotation axis 31 changes. When the laser beam 12 guided by the fluid jet 11 approaches the rotation axis 31 (in the line of sight along its propagation direction), a high throughput can be achieved. Where the profile path 70 is close to the rotation axis 31, the amount of material to be removed can be greater.

[0077] FIG. 8(c) shows two different exemplary cases. In a region where the radius of the workpiece 30 has to be extremely reduced to obtain the desired final shape of the product (Case 1), the laser beam 12 guided by the fluid jet 11 is irradiated more nearly perpendicular (''more perpendicular'') onto the machining surface 32, i.e., the angle at which the laser beam 12 guided by the fluid jet 11 is irradiated onto the machining surface 32 becomes larger. In such a situation, while the ablation efficiency is improved, the surface quality deteriorates. This situation is considered to correspond to an optimal setting for a rough machining process. In a region where the target radius is already close to the initial radius, i.e., where it is necessary to further reduce the radius of the workpiece 30 to obtain the desired final shape of the product (Case 2), the laser beam 12 guided by the fluid jet 11 is irradiated in a state more nearly tangential (''more tangentially'') to the machining surface 32. That is, the angle at which the laser beam 12 guided by the fluid jet 11 is provided to the machining surface 32 is smaller. In this situation, the ablation is not efficient but results in a higher surface quality (lower roughness). This situation may correspond to an optimal setting for a finishing process. In particular, in a region where the radius has to be extremely reduced (i.e., Case 1), the progress of the turning of the workpiece 30 can reduce the radius at a lower ablation rate as it approaches the target radius, but can reduce the radius with better quality.

[0078] The above technical effect is that the turning can be performed effectively and simply by guiding the laser beam 12 guided by the fluid jet 11 along a single invariant profile path 70 perpendicular to the rotation axis 31 while rotating (turning) the workpiece 30. The transition between the rough machining and the finishing can be performed automatically by performing locally self-optimized ablation at any position along the rotation axis 31. After machining the workpiece 30 for a certain time, as it approaches the target radius, the machining quality may become better at the location along the rotation axis 31 where the diameter is the largest. These surfaces may advantageously correspond to the machined surface of the workpiece 30, i.e., the functional surface of the final product.

[0079] In FIGS. 9(a) and 9(b), another example is shown where the laser beam 12 guided by the fluid jet 11 is irradiated in a tangential direction with respect to the machining surface 32 and along the vertical direction (reference direction). Further, the laser beam 12 is irradiated perpendicular to the rotation axis 31 about which the workpiece 30 is rotated 21. In particular, the procedure shown is useful for machining a workpiece 30 having a varying diameter of the workpiece 30, as illustrated for the workpiece 30 in FIGS. 9(a) and 9(b) respectively.

[0080] FIGS. 10 and 11 show a method 20 according to an embodiment of the present invention, based on the embodiment shown in FIGS. 1 and 2. In particular, the method 20 may further include a step 24 of partially cutting the workpiece 30, as shown in FIG. 10. The partial cutting 24 of the workpiece 30 may be performed before the turning (21, 22) of the workpiece 30. The partial cutting 24 and the turning (21, 22) of the workpiece 30 may be performed by the same apparatus 10, and / or may be performed continuously or in one single process. The same elements in FIGS. 10 and 11 as in FIGS. 1 to 9 are labeled with the same reference numerals and are implemented similarly.

[0081] The partial cutting 24 of the workpiece 30 may consist, for example, of separating a series of parts from the workpiece 30 using the laser beam 12 guided by the fluid jet 11 in order to reduce the diameter of the workpiece 30 (where the diameter is perpendicular to the rotation axis 31). In particular, the partial cutting 24 includes a step 81 of cutting into the workpiece 30 with the laser beam 12 guided by the fluid jet 11 to separate a part from the workpiece 30 (first cut), and then further a step 82 of rotating the workpiece 30 by an angle around the rotation axis 31, and still another step 83 of cutting into the workpiece 30 again with the laser beam 12 guided by the fluid jet 11 to separate a part from the workpiece 30 (second cut). In this way, a plurality of parts can be separated from the workpiece 30.

[0082] As further shown in FIG. 10, the partial cutting 24 of the workpiece 30 may consist of making a first cut 81 (as shown in FIG. 10(a), a complete cut is not necessary but possible). Further, thereafter, the workpiece 30 rotates (especially when the first cut 81 itself does not remove a part of the workpiece 30, as shown in FIG. 10(b)), and a further cut (second cut) 83 is made (as shown in FIG. 10(c), the further cut may intersect the first cut), discharging the chips, i.e., removing a part from the workpiece 30. This procedure can be similarly carried out multiple times (FIG. 10(f)) so that finally a series of parts are removed from the workpiece 30 (as shown in FIG. 10(d)). The removal of the series of parts results in the partial cutting 24 of the workpiece 30, i.e., the workpiece 30 can have a shape with a defined surface. In the partial cutting 24, the last part separated from the workpiece 30 (i.e., see FIG. 10(e) for creating the last surface of the workpiece 30) may be cut from the bottom surface of the workpiece 30 because a smaller / shorter cut from this side is required. Thereafter, the partially cut workpiece 30 can be machined according to method 20, in particular, by turning (21, 22).

[0083] FIG. 11 shows different examples of efficient partial cutting plans that can be applied to the workpiece 30. The workpiece 30 is shown in a view along the axis of rotation 31 in FIG. 11. The gray lines drawn on the various workpieces 30 represent cutting lines 90 that can be executed for the partial cutting 24 of each workpiece 30. It can be understood that different arrangements, orientations, and / or sequences of cutting can be performed to efficiently reduce the diameter of the workpiece 30. In some cutting plans, based on the cutting lines 90 shown, in a first step, a first subset, which is a portion, is removed from the workpiece 30, where an angle may be larger (to reduce the diameter of the workpiece 30 with respect to the axis of rotation 31), and then, in a second step, a second subset, which is a portion, is removed from the workpiece 30, where an angle is smaller (to further reduce the diameter of the workpiece 30 with respect to the axis of rotation 31). Thus, the workpiece 30 can be partially cut more coarsely in the first step (roughing), and then can be partially cut more finely in the second step (finishing). The same is possible in the reverse case, i.e., a first step with a smaller angle can be performed, and then a second step with a larger second angle can be performed. In this way, higher accuracy can be achieved.

[0084] The partial cutting plan for the workpiece 30 machined by the method 20 can be determined by an algorithm. For example, an optimization algorithm can be executed based on the size (e.g., volume and / or diameter) and / or shape of the workpiece 30, and / or with respect to the surface finish of the machined workpiece 30, and / or based on the processing time of the workpiece 30. Then, based on the result of the optimization algorithm, the partial cutting 24 (and subsequent turning (21, 22) as well) of the workpiece 30 can be performed. The result can consist of the cutting lines 90, particularly the sequence of cutting represented by such cutting lines 90.

[0085] In one example, the constraints for determining the optimal partial cutting plan for the workpiece 30 may be the maximum radius (e.g., the initial radius or diameter of the workpiece 30, i.e., before the partial cutting 24), and the minimum radius (e.g., the desired final radius or diameter of the workpiece 30 after the partial cutting 24). Further constraints may be the minimum defect size after machining for the workpiece 30. The algorithm for determining the partial cutting plan for the workpiece 30 may then, as an output result, provide the number of surfaces that the workpiece 30 should have after the cutting 24, and / or the most efficient processing sequence for separating a portion from the workpiece 30, i.e., cutting into the workpiece 30. Further, for the partial cutting 24, the maximum volume of material to be removed and the maximum length of each cut may be considered by the algorithm. The final shape of the workpiece 30 may in particular be, for example, a polygon having an offset of the true geometry. The algorithm may be executed by the apparatus 10, and the apparatus 10 may directly use the result of the algorithm to perform, for example, the partial cutting 24 in one execution and then perform turning.

[0086] Turning (21, 22) with or without the partial cutting 24 may be combined with one or more further machining operations, for example, with at least one machining operation consisting of linearly and deeply cutting into the workpiece 30, drilling a hole in the workpiece 30, engraving a number on the workpiece 30, and laser milling the workpiece 30 using the laser beam 12 guided by the fluid jet 11. The apparatus 10 may perform further machining operations in addition to the partial cutting 24 and the turning (21, 22).

[0087] In all embodiments, the method 20 may be executed automatically, and / or continuously, and / or in a single process by the apparatus 10 described below with respect to FIG. 12.

[0088] Figure 12 shows an apparatus 10 according to an embodiment of the present invention. The apparatus 10 is configured to process a workpiece 30, as shown in FIG. 1 or FIG. 2, i.e., it may be the apparatus 10 used in the method 20. The apparatus 10 is composed of at least a processing unit 101, a holder 102, and a control unit 103. The apparatus 10 may further include an optical sensor 103a, a distance sensor 103b, and further optionally other elements and units described below (and shown in dashed boxes).

[0089] The processing unit 101 is configured to provide a laser beam 12 coupled to a pressurized fluid jet 11. The control unit 103 is configured to control the processing unit 101 and the holder 102. In particular, the control unit 103 can control the holder 102 to rotate the workpiece 30 around the rotation axis 31 by 21. Further, the control unit 103 can control the processing unit 101 to irradiate the processing surface 32 of the workpiece 30 with the laser beam 12 guided by the fluid jet 11, especially while the workpiece 30 is rotating by 21. These operations can implement the method 20 according to the embodiment of the present invention as shown in FIGS. 1 and 2.

[0090] The optional optical sensor 103a may be configured to determine the state of the workpiece 30 being machined during machining of the workpiece 30. For example, it can be determined whether the laser beam 12 has penetrated the workpiece 30, is attempting to penetrate the workpiece 30, or has not penetrated the workpiece 30 (for example, when a part of the workpiece 30 is cut off during the partial cutting 24). In this case, the machining process at that time is immediately stopped, and the apparatus 10 can proceed to the next machining process. The distance sensor 103b can be configured to measure the distance between the machining unit 101 and the machining surface 32 of the workpiece 30, for example, during turning (21, 22). Therefore, the apparatus 10 can determine how much material has been removed from the workpiece during turning (21, 22). The distance sensor 103b may be further configured to measure the surface direction of the machining surface 32 of the workpiece 30. Thereafter, the control unit 103 can determine how to irradiate the laser beam 12 guided by the fluid jet 11 on the machining surface 32 based on the measured surface direction, for example, to enable the most efficient turning (21, 22) of the workpiece 30.

[0091] The processing unit 101 may couple the laser beam 12 to the fluid jet 11 so as to receive it, for example, from a laser light source 105 which may optionally be part of the device 10, or from, for example, a plurality of laser light sources 105. This coupling may be carried out in the processing unit 101. The processing unit 101 may in particular include optical elements such as at least one lens 106 for coupling the laser beam 12 to the fluid jet 11. The laser beam 12 may be generated outside the processing unit 101 and may be incident on the processing unit 101. In the processing unit 101, a mirror and / or a beam splitter 107 and / or another optical element may guide the laser beam 12 towards, for example, at least one lens 106. The beam splitter 107 may be used to direct the laser beam 12 or a part of the electromagnetic radiation coming from the workpiece 30 to the optical sensor 103a. The processing unit 101 may also be provided with an optically transparent protective window 109 in order to optically separate the optical arrangement, here exemplified by optical elements, from a fluid circuit (for example a water circuit) and from the region of the processing unit 101 where the fluid jet 11 is generated.

[0092] To generate the fluid jet 11, the processing unit 101 may comprise a fluid jet generation nozzle 108 having an opening of a certain size. The fluid jet generation nozzle 108 may be arranged within the processing unit 101 in order to generate the fluid jet 11 in a protected environment. The opening may define the width of the fluid jet 11. The opening may have a diameter, for example, of from 10 to 200 μm, and the fluid jet 11 may have a diameter, for example, of about 0.6 to 1 times the opening diameter. The pressure for the pressurized fluid jet 11 may typically be provided via an external fluid supply 104 which is not part of the device 10 (but may be). For example, the pressure is between 50 and 800 bar. To output the fluid jet 11 from the device 10, the processing unit 101 may include an outlet nozzle having an outlet opening. The outlet opening is in particular wider than the fluid nozzle opening.

[0093] The control unit 103 may further control at least one laser light source 105 (for example, it may issue an instruction to the laser controller of the laser light source 105). That is, the control unit 103 may issue a command to the laser controller of the laser light source 105 so as to output laser emission according thereto. Thereby, the laser controller of the laser light source 105 can always set continuous laser emission or pulsed laser emission according to the instruction of the control unit 103, and in particular for the latter, it can set the pulse power, pulse width, pulse repetition rate, pulse burst rate, or the pause between pulses. For example, for turning (21, 22), the pulse intensity of the laser beam 12 may be in the range of 0.4 to 2 GW / cm 2 and / or the average power of the laser beam 12 may be in the range of 20 to 300 W, and the pulse length of the laser beam 12 may be in the range of 150 to 400 ns. Further, the control unit 103 may control the fluid supply unit 104.

[0094] During turning (21, 22), the workpiece 30 can be held by the holder 102. The apparatus 10 can be arranged to machine the workpiece 30 held by the holder 102. The holder 102 may be attached to a rotatable element of the apparatus 10 or may itself be a rotatable element of the apparatus 10. The apparatus 10, in particular the control unit 103, can thereby control the movement of the holder 102 in up to three dimensions (e.g., in x - y - z as shown in FIG. 12, the z - direction being parallel to the fluid jet 11, and the x - and y - directions being perpendicular to the z - direction and to each other). The holder 102 can be rotated by the apparatus 10, for example, by rotating a rotatable element. And the apparatus 10 can turn the workpiece 30 (21, 22) in particular by moving the laser beam 12 guided by the fluid jet 11 as described above while rotating the holder 102. Thereby, multi - pass movement can be performed, i.e., the laser beam 12 can be moved multiple times along the same path on the workpiece 30. Further, the movement of the laser beam 12 may be continuous or stepped, and the speed of the movement of the laser beam 12 can be selected / changed. It should be noted that since the movement of the laser beam 12 is relative to the workpiece 30, the workpiece 30 (e.g., held by a movable workpiece holder) can also be moved.

[0095] The rotation of the holder 102 may be driven by a motor or a CNC. For example, the holder 102 may be composed of a rod, i.e., a "dop". The holder 102 may be at least 10% smaller, in particular at least 20% smaller (in terms of diameter / width) than the diameter of the workpiece 30. The holder 102 may rotate about the rotation axis 31 (shown in FIG. 12). The rotation of the holder 102 may be controlled by the control unit 103, in particular based on an input from the optical sensor 103a.

[0096] The optical sensor 103a may be arranged to receive laser-induced electromagnetic radiation propagating from the workpiece 30 (for example, while the workpiece 30 is being machined with the laser beam 12) through, for example, the fluid jet 11 and further through at least one optical element (lens, beam splitter) 106, 107 towards the optical sensor 103a. In particular, the optical sensor 103a may be arranged to receive laser-induced electromagnetic radiation passing through the fluid jet 11 and through at least one optical element 106 configured to couple the laser beam 12 into the fluid jet 11. The laser-induced electromagnetic radiation may include secondary radiation emitted from a portion of the workpiece 30 being machined with the laser beam 12. For example, the laser-induced electromagnetic radiation may be induced because the machined surface 32 of the workpiece 30 changes into a plasma. This plasma can be easily separated on or by the optical sensor 103a and can emit characteristic radiation. The laser-induced electromagnetic radiation can also include primary laser radiation reflected from the workpiece 30. Further, the laser-induced electromagnetic radiation may include secondary radiation generated by scattering of the laser beam 12 in the fluid jet 11, preferably Raman scattering.

[0097] The distance sensor 103b may be a second optical sensor (i.e., in addition to the optical sensor 103a) or an ultrasonic sensor. In this case, the distance sensor 103b may be arranged to optically measure the distance to the workpiece surface and / or the surface orientation of the workpiece 30, for example, by measuring light reflected from the workpiece 30. For this purpose, the distance sensor 103b may also be configured to send light onto the workpiece 30. Further, the distance sensor 103b may be a touch probe. In this case, it may be arranged to be able to contact the workpiece 30 for measuring the surface orientation, or it may be configured to be movable or movable towards the workpiece 30 for performing the measurement.

[0098] The optical sensor 103a and / or the distance sensor 103b may be arranged in the processing unit 101. However, the optical sensor 103a may be arranged in the laser light source 105. In this case, the laser-induced radiation propagates backward from the workpiece 30, is guided through the processing unit 101 to the laser light source 105, and is received there by the optical sensor 103a. The processing unit 101 may be optically connected to the laser light source 105, for example, by an optical fiber.

[0099] Furthermore, the optical sensor 103a may be configured to convert the received radiation into a signal. The control unit 103 may include a processing circuit configured to determine the state of processing / cutting the product (workpiece) 30 based on the signal. The state of processing the workpiece 30 may be whether the laser beam 12 penetrates the workpiece 30.

[0100] The device 10, particularly the control unit 103, may include a processor or processing circuit (not shown) configured to execute, implement, or initiate various operations of the device 10 described in the present disclosure, particularly the method 20. The processing circuit may be composed of hardware, and / or the processing circuit may be controlled by software. The hardware may be composed of an analog circuit or a digital circuit, or both an analog circuit and a digital circuit. The digital circuit may be composed of components such as an application-specific integrated circuit (ASIC), a field-programmable array (FPGA), a digital signal processor (DSP), or a multi-purpose processor.

[0101] The device 10 may further include a memory circuit that stores one or more instructions executable by a processor or a processing circuit, particularly under the control of software. For example, the memory circuit may include a non-transmissive storage medium that stores executable software code or program code (computer program), and when this code is executed by a processor or a processing circuit, various operations of the device described in the present disclosure, particularly the method 20, are executed.

[0102] The present disclosure, like the embodiments, has been described by way of example in combination with various embodiments. However, other variations can be understood and effected by those skilled in the art, who practice the claimed embodiments, from a study of the drawings, the description, and the independent claims. In the claims and description, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. A single element or other unit may perform the functions of several entities or items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

[0103] Embodiments of the present invention have various application scenarios. For example, method 20 may be beneficial for watch manufacturing, for example, due to the achievable low surface roughness, or the perpendicularity of the fluid jet 11 possible with apparatus 10, or the versatility of method 20. For example, method 20 may be carried out to manufacture or shape a pinion or a cogs. Further, method 20 may be beneficial for manufacturing grinding tools, etc., which require usually hard materials. The advantages may come, for example, from the high material removal rate possible with method 20, or the perpendicularity of the fluid jet 11 possible with apparatus 10. Further, method 20 is considered to be beneficial for manufacturing or shaping medical ceramics. The advantages may come, for example, from the high material removal rate possible with method 20, or the delicate processing of materials that are weak and / or brittle to heat by the laser light 12 guided by the fluid jet, especially in the tangential direction.

Description of the Reference Numerals

[0104] 10 apparatus 11 fluid jet (liquid jet) 12 laser light 20 method 21, 22 turning 30 workpiece 31 rotation axis 32 machining surface 101 machining unit 102 Holder 103 Control Unit

Claims

1. A method (20) for machining a workpiece (30), the method (20) being carried out by a device (10) that provides a laser beam (12) guided by a fluid jet (11), the method (20) comprising partially cutting (24) the workpiece (30) before turning (21, 22) the workpiece (30). The partial cutting (24) of the workpiece (30) includes separating a series of portions from the workpiece (30) with the laser beam (12) guided by the fluid jet (11) in order to reduce the diameter of the workpiece (30) with respect to the axis of rotation (31) of the workpiece (30). The turning (21, 22) of the workpiece (30) comprises rotating (21) the workpiece (30) about the axis of rotation (31) during machining, and irradiating (22) the machining surface (32) of the workpiece (30) with the laser beam (12) guided by the fluid jet (11). A method (20).

2. The laser beam (12) guided by the fluid jet (11) is irradiated perpendicular to the machining surface (32), or in a tangential direction with respect to the machining surface (32), or in a substantially tangential direction with respect to the machining surface (32). The method (20) according to claim 1.

3. The axis of rotation (31) is perpendicular to the propagation direction of the laser beam (12) guided by the fluid jet (11) provided by the device (10). The method (20) according to claim 1 or claim 2.

4. The propagation direction of the laser beam (12) guided by the fluid jet (11) does not intersect the axis of rotation (31). The method (20) according to claim 3.

5. The laser beam (12) guided by the fluid jet (11) is irradiated at an angle with respect to the machining surface (32). The method (20) according to claim 3 or claim 4.

6. Further comprising moving (23) the laser beam (12) guided by the fluid jet (11) along the moving direction during the turning (21, 22) of the workpiece (30). The method (20) according to any one of claims 1 to 5.

7. The moving direction is parallel or perpendicular to the axis of rotation (31) and perpendicular to the propagation direction of the laser beam (12) guided by the fluid jet (11). The method (20) according to claim 6.

8. The method (20) according to claim 1 or claim 2, wherein the rotation axis (31) is parallel to the laser beam (12) guided by the fluid jet (11).

9. The laser beam (12) is pulsed, and at the machining surface (32) of the workpiece (30), a rotational speed for rotating the workpiece (30) around the rotation axis (31) is set such that consecutive pulses of the pulsed laser beam (12) overlap each other by at least 50%. The method (20) according to any one of claims 1 to 8.

10. The laser beam (12) is pulsed, and the pulsed laser beam (12) includes at least two overlapping pulses selected based on a specific material of the workpiece (30), wherein the first pulse has a different power and frequency from the second pulse. The method (20) according to any one of claims 1 to 9.

11. The first pulse is suitable for cutting a specific material of the workpiece (30), and the second pulse is not suitable for cutting a specific material of the workpiece (30) and / or is suitable for smoothing the surface of a specific material of the workpiece (30), for example, for smoothing the surface formed by cutting a specific material with the first pulse. The method (20) according to claim 10.

12. Separating the part from the workpiece (30) includes making an incision (81) in the workpiece (30) with the laser beam (12) guided by the fluid jet (11), rotating (82) the workpiece (30) by an angle around the rotation axis (31), and making another incision (83) in the workpiece (30) with the laser beam (12) guided by the fluid jet (11) to cut off the part from the workpiece (30). The method (20) according to any one of claims 1 to 11.

13. The partial cutting (24) of the workpiece (30) is separating a first subset that is a part from the workpiece (30), wherein the angle is a larger angle for reducing the diameter of the workpiece (30) with respect to the rotation axis (31), and To further reduce the diameter of the workpiece (30) with respect to the rotation axis (31), a second subset, which is a part of the workpiece (30), is separated from the workpiece (30), and the certain angle is a smaller angle, the method (20) according to claim 12.

14. Executing an optimization algorithm with respect to the surface finish of the machined workpiece (30) and / or the process time when machining the workpiece (30) based on the size and / or shape of the workpiece (30); The method (20) according to any one of claims 1 to 13, further comprising performing partial cutting (24) and turning (21, 22) of the workpiece (30) based on the result of the optimization algorithm.

15. The method (20) is automatically and / or continuously executed by the device (10), and / or The method (20) is executed by the device (10) in a single process, the method (20) according to any one of claims 1 to 14.

16. An apparatus (10) for machining a workpiece (30), the apparatus (10) comprising: A machining unit (101) configured to provide a laser beam (12) guided by a fluid jet (11); A holder (102) configured to hold and rotate the workpiece (30); and A control unit (103) configured to control the machining unit (101) and the holder (102) respectively to perform partial cutting (24) of the workpiece (30) before turning (21, 22) the workpiece (30). The partial cutting (24) of the workpiece (30) includes separating a series of parts from the workpiece (30) with the laser beam (12) guided by the fluid jet (11) to reduce the diameter of the workpiece (30) with respect to the rotation axis (31). The control unit (103) is further configured to control the machining unit (101) and the holder (102) respectively to turn (21, 22) the workpiece (30). To turn (21, 22) the workpiece (30), the workpiece (30) is rotated (21) about the rotation axis (31) during machining, and The laser beam (12) guided by the fluid jet (11) is irradiated (22) onto the machining surface (32) of the workpiece (30), apparatus (10).

17. A computer program comprising program code for causing a processor, in particular the processor of the control unit (103), to control the apparatus (10) according to claim 16 when executed, or for carrying out the method (20) according to any one of claims 1 to 15 for any of these purposes.

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