Apparatus and method for cleaning a tool for laser welding

Abstract

The invention relates to a method for cleaning a tool (6) for laser welding, wherein: a focused laser beam (3) is moved in an xy-plane (18) by a positioning module (11) of an optical unit (15); and the focused laser beam (3) is moved in the xy-plane (18) and in the z-direction (16) and guided along an inner lateral surface (7) that is to be cleaned of the tool (6) in such a way that attached matter (25) present on the inner lateral surface (7) that is to be cleaned is heated by the focused laser beam (3) and then removed. The invention further relates to an apparatus for cleaning a tool (6) for laser welding and to the use of the apparatus for the method and / or for laser welding.

Description

[0001] DEVICE AND METHOD FOR CLEANING A TOOL FOR LASER WELDING

[0002] The invention relates to a method for cleaning a tool for laser welding, wherein a focused laser beam is moved in an xy-plane by means of a positioning module of an optical unit. The invention further relates to a device for cleaning a tool for laser welding and the use of the device for the method.

[0003] In joining technology, it is known to use a laser beam to create a material-bonded connection between components in a process called deep penetration welding. The components are made of metallic materials, such as copper, aluminum, steel, or corresponding alloys. Due to the nature of the process, the tool used in laser welding becomes contaminated during the welding process. Typically, spatter from the molten metal adheres to an inner surface of the tool, which serves as a hold-down device to press the components against each other, or as a shielding tool to prevent widespread contamination of the components. Therefore, the tool used for laser welding must be cleaned regularly or as needed.In practice, at least the coarse deposits must be removed after a usage time of approximately 10 to 30 minutes to ensure the tool's functionality and a high quality of the weld joint in the long term.

[0004] In practice, chemical cleaning of the tool is possible. Chemical cleaning yields good results, particularly in the reliable and thorough removal of stubborn copper residues. However, this process takes several minutes and involves the use of reactive chemicals that are complex to handle and dispose of. Therefore, chemical cleaning is typically performed offline and only for basic tool preparation. Cleaning tools during an ongoing process is rarely feasible.

[0005] Satisfactory cleaning results can also be achieved by mechanically blasting the inner surface of the tool with a fluid or particle jet. However, integrating such a cleaning method into the ongoing manufacturing process is difficult, making fluid or particle jet cleaning impractical for frequent, rapid tool cleaning during production. Furthermore, as with chemical cleaning, waste products are generated that must be handled separately, and there is a risk of environmental contamination with the blasting media. Finally, the accessibility of the inner surface of the tool is application-dependent, meaning this cleaning method is not universally applicable.

[0006] It is also known to clean the inner surface of the tool mechanically, particularly by brushing or milling. Brushing has the disadvantage that stubborn residues cannot be removed, or cannot be removed completely or reliably. Milling requires a complex cleaning device. Moreover, the relative movement between the milling cutter and the tool must be determined, controlled, and maintained very precisely to avoid damage to the tool or the milling cutter. In addition, copper, as a typical material for the components to be welded, is highly prone to smearing. The cutting edges of the milling cutter then become clogged quickly, and the cleaning effect is significantly reduced.

[0007] The object of the present invention is to provide an improved method and a device for cleaning a tool for laser welding.

[0008] To solve the problem, the invention in conjunction with the preamble of claim 1 is characterized in that the focused laser beam is moved in the xy-plane and guided along an inner surface of the tool to be cleaned in such a way that adhesions present on the inner surface to be cleaned are heated by the focused laser beam and then removed.

[0009] The particular advantage of the invention lies in the fact that the focused laser beam provided by an existing laser unit is used to clean the inner surface of the tool. Therefore, no additional hardware components are required, as in milling, brushing, or blasting, and there is no need for separately handled operating materials, especially chemicals, granular abrasives, or fluids. Consequently, the cleaning method according to the invention can be implemented very cost-effectively. Furthermore, the method can be easily integrated into the ongoing manufacturing process.It has been shown that a thorough cleaning of the tool's inner surface and the removal of interfering deposits can be carried out quickly and with sufficient precision using the focused laser beam. The tool is then refurbished very quickly, allowing it to be reused as a hold-down tool or for shielding the weld area. Even if small residual deposits remain on the tool's inner surface, the primary process—laser welding—is not impaired. This significantly extends the tool's service life. The tool requires far fewer replacements or reconditioning / external cleaning processes, such as chemical cleaning. Consequently, the productivity of the laser welding process also increases.The tool is typically ring- or tube-shaped and has a jacket body that surrounds a passage defined by an entry opening and an exit opening, through which the laser beam is passed during laser welding.

[0010] According to a preferred embodiment of the invention, the duration of the irradiation and / or the laser beam power is determined such that sufficient energy is supplied to the cleaning process to liquefy, burn off, sublimate, or vaporize the deposits. This advantageously results in a good cleaning effect, and the removal of the deposits is particularly easy. For example, an airflow can be provided to remove the deposits. A cleaning device that includes a pump or a vacuum chamber can be used to provide the airflow.

[0011] In an advantageous embodiment of the invention, a focal point of the focused laser beam is moved in a z-direction oriented perpendicular to the xy-plane by means of a height adjustment module of the optical unit. The movements of the focused laser beam in the xy-plane and the z-direction are superimposed, and the focal point of the focused laser beam is guided along an inner surface of the tool to be cleaned. Advantageously, by moving the focal point of the focused laser beam in the z-direction, tools with a vertically inclined inner surface, for example, tools with an inner surface that tapers conically towards the exit opening, can be cleaned equally effectively and quickly. The focused laser beam can then strike the inner surface with its focal point at various positions in the z-direction and remove adhering contaminants.

[0012] According to an advantageous embodiment of the invention, the focused laser beam can be supplied in pulsed, continuous, or selectively pulsed and continuous modes. Advantageously, pulsed operation allows for easy control and regulation of the energy supply during cleaning. In particular, reducing the energy supply prevents damage to the tool or the inner surface being cleaned. Continuous operation is particularly effective for removing heavy soiling or stubborn deposits. In contrast, selective pulsed or continuous operation allows the cleaning process to be tailored to specific requirements for the same device.If, for example, copper components are initially welded using the device, followed later by aluminum components, the cleaning process can be adapted to each situation and the specific components being welded. The focused laser beam can then be pulsed or continuously supplied as needed.

[0013] According to an advantageous embodiment of the invention, the tool is moved to a cleaning unit for cleaning. The cleaning unit can then provide means for supplying the airflow and / or a collection container for the removed deposits and / or an absorber for the focused laser beam. Advantageously, the provision of the cleaning unit counteracts damage to or contamination of the weld metal or the welding system. The cleaning unit can, for example, be spatially and / or functionally integrated into the device, so that the tool can be moved to the cleaning unit and cleaned there using the kinematic components already present in the device. In particular, the laser unit or the optical unit can be moved together with the tool.The absorber can be positioned, in particular, below an exit opening formed in the tool for the focused laser beam, such that the focused laser beam, or a portion thereof, passing through the tool during cleaning of the inner surface, strikes the absorber. This counteracts reflection or scattering of the laser beam, resulting in a particularly reliable cleaning process.

[0014] According to an advantageous embodiment of the invention, the focused laser beam is oriented at an acute angle to the inner surface of the tool to be cleaned during cleaning. This advantageously results in a low area-specific energy input into the tool itself. This counteracts undesirable excessive local heating of the tool or damage to it.

[0015] According to an advantageous embodiment of the invention, the tool is stationary during cleaning; that is, it is not moved or transported. The relative movement of the tool and the laser beam during cleaning is thus achieved via the laser beam. The laser beam is guided along the inner surface of the tool to be cleaned by the positioning module and, optionally, by the height adjustment module, as required. Since only the massless laser beam moves during cleaning while the tool remains stationary, additional actuator components can be dispensed with. Moreover, the cleaning process is characterized by very high dynamics due to the absence of moving masses.

[0016] To solve this problem, the invention provides the features of claim 9. Accordingly, the device for cleaning the tool comprises a laser unit configured to provide a laser beam, in particular a collimated laser beam, a lens configured to provide a focused laser beam, a positioning module configured to move the focused laser beam in the xy-plane, and / or a motion module configured to move the tool into a cleaning position and / or to move the tool during cleaning, a computing unit interacting with the motion module and / or the positioning module, which is configured to calculate a motion trajectory for the tool and / or the focused laser beam along an inner surface of the tool to be cleaned and to provide motion data.as well as a control system that interacts with the motion module and / or the positioning module and the computing unit, and is configured to receive the motion data provided by the computing unit and to control actuators of the positioning module and / or the motion module.

[0017] The device according to the invention for cleaning the tool for laser welding is typically used simultaneously for laser welding. It thus serves as a laser welding system or as part thereof. In particular, the lens, the optical unit, and / or the positioning module can be used to provide the focused laser beam and to move it during laser welding, thereby producing a weld seam. The xy-plane in which the focused laser beam is moved by the positioning module is typically horizontally extended. The focused laser beam, which is guided along the inner surface of the tool to be cleaned, is provided by the laser unit, which also provides the laser beam for laser welding. Similarly, the other elements of an optical unit, in particular the lens, are part of the cleaning device and the laser welding system.They can therefore be used equally for cleaning the inner surface and for laser welding the joining partners. The motion module can, in turn, use actuators of the laser welding system, which are used to position the tool relative to the joining partners and / or to move it in a z-direction positioned perpendicular to the xy-plane, preferably extending vertically. The motion module moves the tool in such a way that, during laser cleaning of the inner surface, the laser welding system or any workpiece (joining partner) provided therein is not contaminated.

[0018] The tool to be cleaned serves as a hold-down device in laser welding, used to fix and / or press the joining partners together, and / or to shield the weld area. It prevents the area around the weld from becoming contaminated or the laser beam from being scattered and / or reflected unintentionally.

[0019] Preferably, the tool is stationary during cleaning, and the laser beam is moved or swiveled. Alternatively, the tool can be moved during cleaning, in which case the laser beam preferably remains stationary. The tool can then be positioned so that the laser beam hits the deposits and removes them. The tool's trajectory is determined, as before, by the processing unit, which interacts with the motion module.

[0020] According to a preferred embodiment of the invention, the device comprises a height adjustment module configured to move a focal point of the focused laser beam in the z-direction, which extends perpendicular to the xy-plane. The device's control system is configured to actuate actuators of the height adjustment module. Advantageously, the height adjustment module allows the focal point of the focused laser beam to be shifted in the z-direction, enabling highly efficient cleaning of a vertically inclined inner surface of the tool. According to a further development of the invention, the device comprises a position detection unit configured to detect the position and / or orientation of the tool. The position detection unit interacts with the processing unit to calculate the motion trajectory of the focused laser beam.For example, the position detection unit can detect when the cleaning position has been reached and / or when the tool is aligned within that position. Information about reaching the cleaning position is particularly sufficient when the tool and the optical unit have a consistent, known relationship to each other. Specifically, by including the position detection unit, the cleaning process can be initiated only after the tool has reached its cleaning position, to which it was moved by the motion module. For instance, the position detection unit provides the processing unit with the position and orientation of the tool to be cleaned, allowing the motion trajectory to be determined based on the tool's precise position.The position detection unit of the device for cleaning the tool may preferably use sensors or other detection means that the laser welding system already provides for detecting the position and / or orientation of the tool during laser welding.

[0021] To calculate the motion trajectory of the focused laser beam, the processing unit uses stored information about the tool's geometry in addition to the tool's position determined by the position sensing unit. This allows the position or orientation of the inner surface to be cleaned to be determined from the tool's position. The position sensing unit can be, for example, an optical position sensing unit and / or utilize optical sensing devices, such as a camera, which are also used in laser welding. Mechanical sensing devices, in particular position sensors and / or motion sensors, can also be incorporated into the position sensing unit.

[0022] According to an advantageous embodiment of the invention, the positioning module provides at least one actuatingly adjustable mirror. In particular, the mirror is actuated to pivot or rotate, and the laser beam is deflected. The adjustment range of the at least one actuatingly adjustable mirror is to be provided with a sufficient size to deflect the laser beam beyond the cross-sectional area of ​​an exit opening formed on the tool for the focused laser beam into the area of ​​the inner surface of the tool to be cleaned. Thus, the adjustment range of the mirrors for the cleaning function must be larger than would be necessary for using the optical unit in pure laser welding. This makes it possible to use the positioning module employed for laser welding to guide the focused laser beam along the inner surface of the tool to be cleaned.No additional deflection devices for the laser beam or supplementary actuators are required.

[0023] To solve this problem, the device according to the invention can be used to carry out the cleaning method according to the invention and thus clean the inner surface of a tool that is used as a hold-down tool in laser welding. Furthermore, the device can be used for laser welding.

[0024] Further advantages, features, and details of the inventive method and device for cleaning the laser welding tool can be found in the dependent claims and the following description. The features mentioned therein can be essential to the invention, either individually or in any combination. Thus, the disclosure relating to the individual aspects of the invention can always be referenced reciprocally. The drawings serve only as examples to clarify the invention and are not intended to be limiting.

[0025] They show:

[0026] Fig. 1 shows a schematic representation of a device according to the invention during laser welding in a first welding position,

[0027] Fig. 2 shows the device according to Fig. 1 during laser welding in a second welding position, Fig. 3 shows the device according to Fig. 1 during laser welding in a third welding position,

[0028] Fig. 4 shows the formation of spatter and adhesion during laser welding.

[0029] Fig. 5 shows the device according to Fig. 1 during the cleaning of a tool for laser welding in a first cleaning position,

[0030] Fig. 6 shows the device according to Fig. 1 during cleaning of the tool for laser welding in a second cleaning position,

[0031] Fig. 7 shows the device according to Fig. 1 during cleaning of the tool for laser welding in a third cleaning position,

[0032] Fig. 8 shows an ideal state of the tool for laser welding after partial cleaning.

[0033] Fig. 9 shows the actual state of the laser welding tool after partial cleaning.

[0034] Fig. 10 shows a schematic representation of a first embodiment of a cleaning device and

[0035] Fig. 11 shows a schematic representation of a second embodiment of the cleaning device.

[0036] Figures 1 to 3 show a device for laser welding. The device serves to weld two joining partners 4, 5 together. It comprises an optical unit 15, a tool 6, and a laser unit (not shown) that provides a collimated laser beam 1. The laser beam 1 strikes a height adjustment module 10 of the optical unit 15 and exits it as a slightly focused laser beam 2. The slightly focused laser beam 2 is deflected in a positioning module 11 of the optical unit 15, which in this exemplary embodiment comprises, by way of example, a first pivotable mirror 12 and a second pivotable mirror 13. It then strikes a lens 14 of the optical unit 15 and exits it as a focused laser beam 3. A focal point of the focused laser beam 3 is located at the welding point.

[0037] In order to join the joining partners 4, 5 materially by means of the focused laser beam 3 and in particular to form a weld seam lying in an xy-plane 18, the laser beam is moved in the xy-plane 18 by the positioning module 11.

[0038] To ensure a high-quality connection between the joining partners 4 and 5, the joining partners 4 and 5 are pressed against each other. The tool 6 serves to press the joining partners 4 and 5 together. It has a through-hole extending perpendicular to the xy-plane 18 in a z-direction 16, with an inlet opening 9 and an outlet opening 8 for the focused laser beam 3, as well as a outer body that is bounded internally by an inner surface 7 of the tool 6.

[0039] For example, the first pivotable mirror 12 can be used to deflect the laser beam 2 in an x-direction of the xy-plane 18. The second pivotable mirror 13 then serves to deflect the laser beam 2 in a y-direction of the xy-plane 18.

[0040] The movement of the focused laser beam 3 during the welding process is always such that the laser beam 3 is focused onto the joining partners 4, 5 in the area of ​​the exit aperture 8 and is spaced apart from an edge of the exit aperture 8 and the inner surface 7 of the laser welding tool 6. The exit aperture 8 thus also defines a movement area for the focused laser beam 3.

[0041] During the metallurgical bonding of the joining partners 4 and 5, they are melted by the focused laser beam 3. A melt 20 of liquid metal forms, containing a vapor capillary 21 (see Fig. 4). A vapor flare 22 is formed above the vapor capillary 21. When the melt 20 solidifies, a welded area 23 is formed, in which the joining partners 4 and 5 are metallurgically bonded. Additionally, spatter 24 is produced during the welding process, which detaches from the melt 20. When the spatter 24 hits the inner surface 7 of the tool 6 and solidifies there, deposits 25 form. These deposits 25, which grow and become larger during the welding process, reduce the effectively available cross-sectional area of ​​the through-hole 8 of the tool 6 and thus restrict the range of movement for the focused laser beam 3 during the welding process.To ensure the continued functionality of the device during laser welding, the deposits 25 must be removed from the inner surface 7 of the laser welding tool 6 from time to time. It has proven advantageous to at least roughly clean the inner surface 7 approximately every 10 to 30 minutes and, in addition, to subject the tool 6 to more thorough cleaning at longer intervals.

[0042] The invention now provides for the laser unit and the optical unit 15 to also be used for removing the adhesion 25. The core idea is to direct the focused laser 3 onto the inner surface 7 of the tool 6 or the adhesions 25 present there, and to burn away, vaporize, sublimate, or liquefy the adhesions 25 with the aid of the focused laser beam 3 and transport them away.

[0043] The process of removing the deposits 25 is illustrated by way of example in Figures 5 to 7. For this purpose, the focused laser beam 3 is preferably guided continuously at a constant or variable speed along a calculated trajectory. A focal point of the laser beam 3 is initially directed at the portion of the deposits 25 that is furthest from the exit opening 8 of the tool 6. Subsequently, the focal point of the laser beam 3 is lowered towards the exit opening 8, and a central region of the deposits 25 is then cleaned. The height adjustment module 10 of the optical unit 15 serves to lower the focal point of the laser beam 3 in the z-direction 16. The focal point of the laser beam 3 is then lowered further so that a region of the inner surface 7 to be cleaned, immediately adjacent to the exit opening 8 of the tool 6, is cleaned by means of the laser beam 3.

[0044] In the present embodiment of the invention, the focused laser beam 3, which is oriented essentially vertically, strikes the inner surface 7 of the tool 6, which is inclined slightly to the vertical, at an acute angle. The through-hole of the tool 6 is conically shaped and widens from the exit opening 8 towards the inlet opening 9. The acute angle at which the laser beam 3 strikes the inner surface 7 to be cleaned results in a very effective and rapid cleaning of the inner surface 7.

[0045] The device for cleaning the tool 6 for laser welding optionally includes a position detection unit (not shown). This unit serves to detect the cleaning position of the tool 6 and / or its position before or during cleaning. If the position and geometry of the tool 6 are known, the trajectory of the focused laser beam 3 can be calculated.

[0046] The device also includes a computing unit and a controller. The controller and computing unit are not shown in the drawings. The computing unit determines the motion trajectory for the focused laser beam 3 and also provides motion data. The motion data, which is then transmitted to the controller, is processed by the controller. The controller then actuates actuators (not shown) of the height adjustment module 10 and the positioning module 11 of the optical unit 15. This makes it possible to move the laser beam in the xy-plane 18 and to shift the focal point of the laser beam 3 in the z-direction. In this way, the inner surface 7 of the tool 6 to be cleaned can be traversed during cleaning.

[0047] If the laser beam 3 exits the tool 6 completely or partially through the exit opening 8 during the cleaning of the inner surface 7 of the tool 6, it strikes an absorber 30 arranged in front of the exit opening 8. The absorber 30 essentially absorbs the incident laser beam 3, so that, in particular, an undirected reflection of the laser beam 3 is prevented.

[0048] Fig. 8 shows a section-by-section completely cleaned, adhesion-free surface

[0049] Inner surface 26.1 of the tool 6. This ideal condition after cleaning will typically not be achievable. Rather, after laser cleaning, residual contamination 26.2 will always remain on the inner surface 7 of the tool 6, see Fig. 9. However, the thickness of the residual contamination 26.2 is significantly less than that of the original adhesion 25; in particular, it is so low that it does not impair welding function.

[0050] To clean the tool 6, the device for cleaning the tool 6 can include a cleaning unit, wherein the absorber 30 can be implemented as a component of the cleaning unit. In addition to the absorber 30, the cleaning unit includes, for example, a pump 31 configured to provide an airflow 33 through the opening of the tool 6 during the cleaning process. Optionally, a vacuum chamber 32 and / or a collection container for the removed deposits can also be provided. Optionally, the vacuum chamber 32 can also serve as a collection container for the deposits 25.

[0051] A first embodiment of the cleaning device is shown in Fig. 10. Here, the airflow 33, which is generated by the pump 31, is directed from the outlet opening 8 towards the inlet opening 9 of the tool 6. Air thus flows into the tool 6 through the outlet opening 8 for the focused laser beam 3 and exits through the inlet opening 9. The vacuum chamber 32, which also serves as a collection container for the removed deposits, is connected to the inlet opening 9. During the cleaning process, the focused laser beam 3 therefore passes through the vacuum chamber 32 before entering the interior of the tool 6 through the inlet opening 9 and striking the inner surface 7 to be cleaned, or the deposits 25 located there.

[0052] A second embodiment of the cleaning device according to Fig. 11 provides that the air, like the focused laser beam 3, enters the tool 6 via the inlet opening 9 and exits the tool 6 via the outlet opening 8. The vacuum chamber 32 is associated with the outlet opening 8 of the tool 6. The absorber 30 is arranged in the vacuum chamber 32. Identical components and component functions are identified by the same reference numerals.

[0053] Reference symbol list

[0054] 1 collimated laser beam

[0055] 2 slightly focused laser beams

[0056] 3 focused laser beam

[0057] 4 joining partners

[0058] 5 joining partners

[0059] 6 tools

[0060] 7 Inner surface

[0061] 8 Exit opening

[0062] 9 Entrance opening

[0063] 10 Height adjustment module

[0064] 11 Positioning module

[0065] 12 mirrors

[0066] 13 mirrors

[0067] 14 Lens

[0068] 15 optical units

[0069] 16 z-direction

[0070] 18 xy-plane

[0071] 20 Melt

[0072] 21 vapor capillaries

[0073] 22 steam torch

[0074] 23 welded area

[0075] 24 spritzers

[0076] 25 Adhesion

[0077] 26.1 cleaned inner mantle surface

[0078] 26.2 Residual pollution

[0079] 30 absorbers

[0080] 31 Pump

[0081] 32. Low-pressure chamber

[0082] 33 Airflow

Claims

Patent claims 1. Method for cleaning a tool (6) for laser welding, wherein a focused laser beam (3) is moved in an xy-plane (18) by means of a positioning module (11) of an optical unit (15), characterized in that the focused laser beam (3) is moved in the xy-plane (18) and guided along an inner surface (7) of the tool (6) to be cleaned in such a way that deposits (25) present on the inner surface (7) to be cleaned are heated by the focused laser beam (3) and then removed.

2. Method according to claim 1, characterized in that when the adhesions (25) are heated by the focused laser beam (3) so much energy is supplied that the adhesions (25) are liquefied and / or burned off and / or sublimated and / or vaporized.

3. Method according to claim 1 or 2, characterized in that an airflow (33) is passed through the tool (6) during cleaning.

4. Method according to one of claims 1 to 3, characterized in that a focal point of the focused laser beam (3) is moved by means of a height adjustment module (10) of the optical unit (15) in a z-direction (16) oriented perpendicular to the xy-plane (18) and that the movements of the focused laser beam (3) in the xy-plane (18) and the z-direction (16) are superimposed and the focal point of the focused laser beam (3) is guided along an inner surface (7) of the tool (6) to be cleaned.

5. Method according to one of claims 1 to 4, characterized in that the focused laser beam (3) is pulsed and / or continuously supplied.

6. Method according to one of claims 1 to 5, characterized in that the tool (6) is moved to a cleaning device for cleaning, which includes means for generating the airflow (33) and / or an absorber (30) for the provides a focused laser beam (3) and / or a collection container for the removed adhesions (25).

7. Method according to one of claims 1 to 6, characterized in that the focused laser beam (3) is oriented at an acute angle of less than 45° and preferably less than 30° onto the inner surface (7) of the tool (3) to be cleaned and / or that the focused laser beam (3) is oriented vertically.

8. Method according to one of claims 1 to 7, characterized in that the tool (6) is provided in a fixed position during cleaning.

9. Device for cleaning a tool (6) for laser welding comprising a laser unit configured to provide a laser beam, a lens (14) configured to provide a focused laser beam (3), a positioning module (11) configured to move a focused laser beam (3) in an xy-plane (18), and / or a motion module configured to move the tool (6) into a cleaning position and / or to move the tool (6) during cleaning, a computing unit interacting with the motion module and / or the positioning module (11), configured to calculate a motion trajectory for the tool (6) and / or the focused laser beam (3) along an inner surface (7) of the tool (6) to be cleaned and to provide motion data, a controller interacting with the motion module and / or the positioning module (11) on the one hand and the computing unit on the other hand,set up to receive data from the computing unit, provided motion data and for controlling actuators of the positioning module (11) and / or the motion module.

10. Device according to claim 9, characterized in that the device comprises a height adjustment module (10) which is configured to move a focal point of the focused laser beam (3) in a z-direction (16) extending perpendicular to the xy-plane (18), wherein the control is configured to control actuators of the height adjustment module (10).

11. Device according to claim 9 or 10, characterized in that the device comprises a position detection unit which is configured to detect a position of the tool (6), wherein the position detection unit cooperates with the computing unit to calculate the motion trajectory for the focused laser beam (3).

12. Device according to one of claims 9 to 11, characterized in that the positioning module (11) provides at least one actuating adjustable mirror (12, 13), wherein an adjustment range of the at least one mirror (12, 13) is larger than a cross-sectional area of ​​an exit opening (8) formed on the tool (6) for the focused laser beam (3).

13. Device according to one of claims 10 to 12, characterized in that the height adjustment module (10) is provided between the laser unit and the positioning module (11).

14. Device according to one of claims 9 to 13, characterized in that means for moving the tool (6) and an optical unit (15) comprising the height adjustment module (10) and / or the positioning module (11) and / or the lens (14) are provided in the xy-plane (18) and in the z-direction (16).

15. Use of a device according to any one of claims 9 to 14 for carrying out a method for cleaning an inner surface (7) of a tool (6) for laser welding according to any one of claims 1 to 8 and / or for laser welding.

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