Laser processing apparatus and method for processing a workpiece

Abstract

The invention relates to a laser machining device (1) for machining a workpiece (7), comprising a laser beam supply device (2) which is designed to supply a laser beam for machining the workpiece (7), a transverse jet device (9) which is designed to supply a gas stream (10) which at least partially covers the laser beam supply device (2) towards the workpiece (7) and flows obliquely or perpendicularly to the laser beam, and an overpressure device (13) which is designed to generate an overpressure on the side of the laser beam supply device (2) facing the gas stream (10).

Description

Technical Field

[0001] This invention relates to a laser processing apparatus for processing workpieces and a method for processing workpieces using a laser processing apparatus. Background Technology

[0002] An apparatus for a laser hybrid welding process is known from EP1607167A1, wherein components, such as a laser or laser optics system or optical focusing unit, and elements of a welding torch for an arc welding process and / or a wire supply device, as well as a device for forming a cross-jet, are arranged on at least one mounting element. This apparatus is connected to a compressed air supply device via at least one input and output conduit. The input and output conduits for the compressed air for the cross-jet are arranged between two components, particularly between the laser or laser optics system or optical focusing unit and the elements of the welding torch or the wire supply device.

[0003] Additionally, a laser processing head for machining workpieces, particularly cutting workpieces, by means of a laser beam is known from DE10226359A1. This laser processing head includes a housing, a laser nozzle, and a focusing lens optical system disposed within the housing. The laser nozzle is disposed on the housing in a region of the housing's exhaust opening. The focusing lens optical system defines a working optical path within the housing in a channel for the laser beam, guiding the working optical path from an inlet opening of the housing to an open exhaust opening, and focusing the laser beam passing through the laser nozzle to a working focal point. Furthermore, the laser processing head includes a transverse jet device disposed in the region of the exhaust opening between the housing and the laser nozzle. This transverse jet device is used to generate a gas flow extending transversely to the laser beam. The transverse jet device has a gas inlet opening and an exhaust opening opposite the gas inlet opening regarding the working optical path. Summary of the Invention

[0004] The objective of this invention is to provide a solution in which the laser beam supply device can be particularly well protected from damage due to contact with molten spatter when processing workpieces by means of a laser beam.

[0005] The task described herein is solved by the subject matter of the independent claims. Further possible solutions to the invention are disclosed in the dependent claims, the description, and the drawings. Features, advantages, and possible solutions set forth in the scope of the description with respect to one of the subjects of the independent claims can be at least similarly regarded as features, advantages, and possible solutions of the corresponding subjects of the other independent claims, as well as features, advantages, and possible solutions of any possible combination of the subjects of the independent claims (perhaps in combination with one or more dependent claims).

[0006] This invention relates to a laser processing apparatus for machining workpieces. The laser processing apparatus includes a laser beam providing device configured to provide a laser beam for machining the workpiece. Here, the laser beam providing device is configured to align the laser beam onto the surface of the workpiece, thus allowing the workpiece to be machined by means of the laser beam. Within the range of workpiece machining by means of the laser beam, the workpiece can be at least partially melted, thus forming a liquid melt. To prevent spatter from this liquid melt from reaching and damaging the laser beam providing device, the laser processing apparatus includes a transverse jet device configured to provide a gas flow that at least partially covers the laser beam providing device towards the workpiece and flows obliquely or perpendicularly to the laser beam. This gas flow can also be referred to as a so-called cross jet. Because the gas flow flows obliquely or perpendicularly to the beam direction of the laser beam, molten spatter splashing from the workpiece towards the laser beam providing device is deflected by the gas flow. Therefore, the risk of molten spatter adhering to the laser beam providing device is kept particularly low. Because the gas flow passes perpendicularly or obliquely to the laser beam supply device, negative pressure can be generated in the area of ​​the laser beam supply device due to the turbulence of the ambient air. Consequently, molten spatter can be drawn towards the laser beam supply device. To avoid this, laser processing apparatuses are equipped with an overpressure device designed to generate overpressure on the side of the laser beam supply device facing the gas flow. This generated overpressure effectively prevents the drawing of molten spatter towards the laser beam supply device, thus minimizing the risk of damage to the laser beam supply device due to contact with the molten spatter.

[0007] In this first embodiment, a single compressed air source is specified, designed to supply compressed air not only to the overpressure device but also to the transverse jet device. In this case, the overpressure device includes a throttle for restricting the compressed air used to set the overpressure. To set the overpressure and provide the gas flow, compressed air with different pressures is required. If the compressed air used not only to provide the gas flow but also to set the overpressure is supplied by the same compressed air source, then the overpressure device includes the throttle to set, and in particular reduce, the pressure of a portion of the compressed air supplied by the compressed air device, which is set to set the overpressure.

[0008] Alternatively, the laser processing apparatus may include two distinct compressed air sources: a first compressed air source and a second compressed air source. The first compressed air source has a first compressed air level, and the second compressed air source has a second compressed air level that is lower than the first compressed air level. The first compressed air source is configured to supply compressed air to a transverse jet device for generating a gas flow. The second compressed air source is configured to supply compressed air to an overpressure device for setting an overpressure. Because compressed air is supplied to the transverse jet device and the overpressure device by means of correspondingly distinct compressed air sources, the compressed air pressures required for the respective functions can be set separately and precisely with particular simplicity. If the compressed air for generating the gas flow and the compressed air for setting the negative pressure are supplied by the same compressed air source, the laser processing apparatus can be manufactured with a particularly small number of components and in a particularly compact manner.

[0009] In one possible extension of the invention, the transverse jet device is configured to provide a gas flow that passes beside the protective glass of the optical system of the laser beam providing device, thus at least partially shielding the protective glass towards the workpiece. The overpressure device is configured to set an overpressure in the area of ​​the protective glass. Therefore, the protective glass can be particularly well protected from molten spatter adhesion. Consequently, the risk of contamination of the optical system, and especially the risk of contamination of the protective glass, can be kept particularly low.

[0010] In another possible embodiment of the invention, the protective glass is held by means of a support, and the protective glass and the support together form a can, the can being oriented with its opening toward the workpiece. Here, the bottom of the can is formed by the protective glass. The corresponding sidewalls of the can are formed by the support. An overpressure device is provided to set an overpressure in the can. This thus avoids air being drawn from the can and thus creating a negative pressure in the can due to turbulence generated by ambient air passing through the gas flow. By setting the overpressure, air drawing caused by ambient air turbulence can be compensated for. Therefore, it can be particularly well avoided that molten spatter is drawn into the can due to the negative pressure present in the can, adheres to the protective glass, and thus contaminates the protective glass.

[0011] In this relationship, it can be specifically stipulated that the support has at least one overpressure opening leading into the tank, through which compressed air for setting the overpressure can be introduced into the tank. Through said at least one overpressure opening, compressed air can be introduced directly into the tank with particular simplicity and precision, thus the overpressure can be set in the tank with particular simplicity and precision.

[0012] In another possible embodiment of the invention, the overpressure device is configured to provide at least one airflow for setting the overpressure, the airflow at least partially exiting the laser beam processing apparatus. The airflow can be generated by guiding compressed air through the at least one overpressure opening in the support into the tank. The airflow at least partially exiting the laser supply apparatus can be understood as the airflow flowing at least partially toward the workpiece in the beam direction of the laser beam. Here, the at least one airflow can additionally flow partially in at least one other direction. For example, the at least one airflow can flow from the support toward the center of the tank, wherein the airflow flows obliquely away from the protective glass rather than obliquely toward it. Therefore, additionally by means of the at least one air jet, molten spatter arriving in the tank can be deflected or entrained by the airflow and thus prevented from adhering to the protective glass. Therefore, the risk of molten spatter adhering to the protective glass can be kept particularly low.

[0013] In another possible embodiment of the invention, the laser processing apparatus is configured for welding workpieces. Welding is understood as the merging or fusion of multiple workpieces under heat and / or pressure, such that the workpieces form a unit. Through welding, the materials of the workpieces are interlocked. Welding relates to a joining method for permanently joining two or more workpieces. Thus, by means of a laser processing apparatus, a workpiece can be joined to at least one other workpiece particularly reliably and permanently by welding, wherein the risk of damage to or contamination of the laser beam supply device can be kept particularly low.

[0014] The present invention also relates to a method for processing a workpiece using a laser processing apparatus, as described in the section on the relationship between the laser processing apparatus and the present invention. In this method, a laser beam for processing the workpiece is provided, particularly aligned with the workpiece, using a laser beam providing device. Furthermore, the method specifies that a gas flow is provided using a transverse jet device, the gas flow at least partially obscuring the laser beam providing device towards the workpiece and flowing obliquely or perpendicularly to the laser beam. Additionally, the method specifies that an overpressure is set on the side of the laser beam providing device facing the gas flow using an overpressure device. Here, it is stipulated that either the overpressure is provided by means of a compressed air source configured to supply compressed air to both the overpressure device and the transverse jet device, the overpressure device including a throttle for throttling the compressed air used to set the overpressure; or it is stipulated that a first compressed air source having a first compressed air level and a second compressed air source having a second compressed air level lower than the first compressed air level are provided, with compressed air supplied to the transverse jet device by means of the first compressed air source and to the overpressure device by means of the second compressed air source. The first and second compressed air sources are separately configured, independently operated, and therefore separately operable. In particular, it is stipulated that the gas flow provided by the transverse jet device completely covers the protective glass of the laser processing apparatus, especially the opening of the canister, towards the workpiece in a plane extending perpendicular to the beam direction of the laser beam.

[0015] Other features of the invention can be obtained from the claims, the drawings, and the description taken in conjunction with the drawings. Features and combinations of features mentioned above in the specification, as well as features and combinations of features shown separately in the description taken in conjunction with the drawings and / or in the drawings, may be applied not only in the correspondingly described combinations, but also in other combinations, or may be applied separately, without departing from the scope of the invention. Attached Figure Description

[0016] The attached image is as follows: Figure 1 A schematic side view showing the components of a laser processing apparatus used to process workpieces. Detailed Implementation

[0017] exist Figure 1In the schematic side view, a laser processing apparatus 1 for processing workpiece 7 is partially shown. This laser processing apparatus 1 is currently set up for welding workpiece 7, particularly welding the workpiece to another workpiece 7. The laser processing apparatus 1 includes a laser beam providing device 2, a protective glass 3 (only the optical system of the laser beam providing device 2 is described here), and a support 4 for the protective glass 3. The protective glass 3 is held by means of the support 4. The protective glass 3 and the support 4 together form a container 5, which is positioned with its opening 6 facing the workpiece 7. The bottom of the container 5 is formed by the protective glass 3.

[0018] A laser beam providing device 2 is configured to provide a laser beam and align it with the workpiece 7. During the processing of the workpiece 7, particularly during welding, molten spatter 8 may be generated and ejected towards the laser beam providing device 2. The laser beam is designed to align with the workpiece 7 through the protective glass 3, through the tank 5, and through the opening 6. If molten spatter 8 enters the tank 5, it can adhere to the protective glass 3 and thus contaminate it. This can negatively affect the characteristics of the laser beam provided by the laser beam providing device 2. To prevent molten spatter 8 from entering the tank 5 and thus reaching the protective glass 3, the laser processing apparatus 1 currently includes a transverse jet device 9. The transverse jet device 9 is configured to provide a gas flow 10 that at least partially obscures the laser beam providing device 2 towards the workpiece 7 and flows obliquely or perpendicularly to the direction of the laser beam. Figure 1 It can be seen particularly well how the molten spatter 8 flowing towards the protective glass 3 is deflected by the gas flow 10. For example, in Figure 1 The gas flow 10 provided by the transverse jet device 9 is particularly well visible in the middle, flowing past the protective glass 3 or the opening 6 of the tank 5, and in this case, at least partially covering the protective glass 3 or the opening 6 of the tank 5 toward the workpiece 7.

[0019] The gas flow 10 can cause turbulence 11 in the ambient air, and as long as the turbulence flows beside the opening 6 of the tank 5, the turbulence can draw air 12 from the tank 5. To avoid the formation of a negative pressure in the tank 5 due to air being drawn from it, and thus prevent molten spatter 8 from being drawn into the tank 5, the laser processing apparatus 1 includes... Figure 1 The overpressure device 13 is schematically represented by a block. The overpressure device 13 is configured to generate overpressure on the side of the laser beam supply device 2, particularly the protective glass 3, facing the gas flow 10, currently within the tank 5. Therefore, the ingestion of molten spatter 8 into the tank 5 can be reliably prevented. The overpressure device 13 is thus configured to set overpressure in the area of ​​the protective glass 3, particularly within the tank 5.

[0020] In the current specification, the support 4 has at least one, and currently multiple, overpressure openings 14 through which compressed air for setting the overpressure can be introduced into the tank 5. Here, the overpressure openings 14 are configured such that the introduction of compressed air into the tank 5 generates corresponding airflows 15, which flow at least partially away from the laser beam providing device 2, and in particular the protective glass 3. The airflows 15 are therefore angled away from the protective glass 3 and directed toward the workpiece 7. The overpressure device 13 is thus provided to provide the at least one airflow 15 for setting the overpressure.

[0021] In the current specification, the laser processing apparatus 1 includes a first compressed air source having a first compressed air level and a second compressed air source having a lower second compressed air level than the first compressed air source, and being different from the first compressed air source. The first compressed air source is configured to supply compressed air to the transverse jet device 9, thereby the transverse jet device 9 generates a gas flow 10 by means of the compressed air obtained from the first compressed air source. The second compressed air source is configured to supply compressed air to the overpressure device 13, thereby the overpressure device 13 can generate the at least one air flow 15 by means of the compressed air obtained from the second compressed air source.

[0022] Alternatively, the laser processing apparatus 1 may be equipped with only one compressed air source, which provides compressed air not only for the transverse jet device 9 but also for the overpressure device 13. In order to be able to set the pressure level of the compressed air required to generate the airflow 15, the overpressure device 13 in this embodiment includes at least one throttle.

[0023] Overpressure in the area of ​​the optical system of the laser beam providing device 2, especially in the area of ​​the protective glass 3, prevents the suction of particles and molten spatter 8, which can cause contamination of the protective glass 3.

[0024] During laser welding, molten spatter 8 is inevitably generated due to the instability of the vapor capillary (also known as the so-called keyhole). This molten spatter 8 can reach the protective glass 3 of the optical system. Therefore, the welding process is affected, and in the worst case, the optical system is damaged. An attempt is made to deflect the molten spatter 8 away from the optical system by means of a gas flow 10 (which is a so-called cross-jet). Due to the high volumetric flow rate of the gas flow 10, a negative pressure can be generated in the tank 5 below the protective glass 3 in the absence of an air flow 15. This negative pressure can attract the molten spatter 8. To prevent the negative pressure, at least one air flow 15 is generated between the gas flow 10 and the protective glass 3. This overpressure compensates for the negative pressure and thus reduces contamination of the optical system, especially the protective glass 3.

[0025] This invention generally demonstrates how optimized spatter protection can be achieved for welding optics systems.

[0026] List of reference numerals

[0027] 1. Laser processing equipment

[0028] 2. Laser beam supply device

[0029] 3. Protective Glass

[0030] 4 brackets

[0031] 5 cans

[0032] 6 Openings

[0033] 7. Workpiece

[0034] 8. Melt spatter

[0035] 9. Lateral jet device

[0036] 10 Gas Flow

[0037] 11 Turbulence

[0038] 12 Air

[0039] 13 Overpressure device

[0040] 14 Overpressure opening

[0041] 15. Airflow

Claims

1. A laser processing apparatus (1) for processing a workpiece (7), the laser processing apparatus comprising: A laser beam providing device (2) is provided for providing a laser beam for processing workpiece (7); A transverse jet device (9) configured to provide a gas flow (10) that at least partially covers the laser beam providing device (2) toward the workpiece (7) and flows obliquely or perpendicularly to the laser beam; and an overpressure device (13) configured to generate overpressure on the side of the laser beam providing device (2) facing the gas flow (10); wherein, - A compressed air source is provided, which is configured to supply compressed air to the overpressure device (13) and the transverse jet device (9), the overpressure device (13) including a throttle for throttling the compressed air configured to set the overpressure; or - A first compressed air source and a second compressed air source are provided, the first compressed air source having a first compressed air level and the second compressed air source having a second compressed air level that is lower than the first compressed air level, the first compressed air source being configured to supply compressed air to the transverse jet device (9), and the second compressed air source being configured to supply compressed air to the overpressure device (13).

2. The laser processing apparatus (1) according to claim 1, characterized in that, The transverse jet device (9) is provided for providing the gas flow (10) which passes next to the protective glass (3) of the optical system of the laser beam providing device (2) and thus at least partially covers the protective glass (3) toward the workpiece (7), and the overpressure device (13) is provided for setting overpressure in the area of ​​the protective glass (3).

3. The laser processing apparatus (1) according to claim 2, characterized in that, The protective glass (3) is held by means of a bracket (4), and the protective glass and the bracket together form a can (5) with its opening (6) facing the workpiece (7). The bottom of the can (5) is formed by the protective glass (3), and the overpressure device (13) is provided for setting overpressure in the can (5).

4. The laser processing apparatus (1) according to claim 3, characterized in that, The bracket (4) has at least one overpressure opening (14) leading into the tank (5), through which compressed air for setting overpressure can be introduced into the tank (5).

5. The laser processing apparatus (1) according to any one of the preceding claims, characterized in that, The overpressure device (13) is configured to provide at least one airflow for setting overpressure, the airflow flowing away from the laser beam processing device (2) at least in part.

6. The laser processing apparatus (1) according to any one of the preceding claims, characterized in that, The laser processing device (1) is set up for welding workpieces (7).

7. A method for processing a workpiece (7) using a laser processing apparatus (1) according to any one of the preceding claims, wherein, A laser beam for processing the workpiece (7) is provided by means of a laser beam providing device (2); a gas flow (10) is provided by means of a transverse jet device (9), the gas flow at least partially obscuring the laser beam providing device (2) toward the workpiece (7) and flowing obliquely or perpendicularly to the laser beam; and an overpressure is set on the side of the laser beam providing device (2) toward the gas flow (10) by means of an overpressure device (13); wherein, - Overpressure is provided by means of a compressed air source configured to supply compressed air to the overpressure device (13) and the transverse jet device (9), the overpressure device (13) including a throttle for throttling the compressed air used to set the overpressure; or - A first compressed air source with a first compressed air level and a second compressed air source with a second compressed air level lower than the first compressed air level are provided. Compressed air is supplied to the transverse jet device (9) by means of the first compressed air source and compressed air is supplied to the overpressure device (13) by means of the second compressed air source.

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