Method and laser working system for laser working a workpiece

Abstract

The invention relates to a method for laser working a workpiece (1), in which method a welding pattern (2) is generated in the workpiece (1) by means of a plurality of pulsed laser beams (4), the pulsed laser beams (4) being applied to the workpiece (1) at the same time in order to generate the welding pattern (2).

Description

[0001] Method and laser processing system for laser processing of a workpiece

[0002] The present invention relates to a method and a laser processing system for laser processing of a workpiece, in which a welding pattern is generated in the workpiece by means of a plurality of pulsed laser beams.

[0003] Laser welding is an established process for machining workpieces, performed with both continuous (CW) and pulsed laser beams. Typically, a relative movement between the laser beam and the workpiece is involved to create the desired weld path or weld contour. Particularly with pulsed laser systems, the weld seams are built up step by step by combining multiple laser pulses. The total duration of the welding process is the sum of the pulse and idle times, which significantly influences the processing time.

[0004] A significant disadvantage of these established methods is that the welding speed in continuous wave (CW) processes cannot be increased arbitrarily due to dynamic limitations in the weld pool. These weld pool dynamics, such as spatter or material ejection, restrict the possibility of accelerating the process without compromising weld quality. Even when using pulsed laser beams, the reduction in process time is limited. The physical properties of the laser pulses and the dynamic limitations of the processing optics also impose natural limits on the welding speed.

[0005] Furthermore, known methods, particularly pulsed systems, exhibit melt pool dynamic effects that can further impair the welding process. These effects not only lead to a reduction in welding speed but also to an increased susceptibility to defects, for example, due to spatter or uncontrolled material movement in the melt pool. This negatively affects the quality of the welds and may necessitate rework. Therefore, the object of the invention is to provide an improved method and an optimized laser processing system for laser processing of a workpiece that avoids or at least reduces the problems known from the prior art.

[0006] This task is solved by a method for laser processing of a workpiece in which a welding pattern is created in the workpiece by means of a plurality of pulsed laser beams, whereby the pulsed laser beams are applied to the workpiece simultaneously with the creation of the welding pattern.

[0007] This method offers the advantage of significantly increasing welding speed, as multiple pulsed laser beams are applied to the workpiece simultaneously. This allows for the creation of larger weld patterns in a shorter time, resulting in a substantial reduction in process time. Furthermore, the simultaneous irradiation of the weld path stabilizes the melt pool dynamics, improving the quality of the welds and reducing defects such as spatter or ejection. Overall, this leads to more efficient use of the laser source and a more robust welding process.

[0008] First, the individual elements of the claimed invention are explained in the order in which they are mentioned in the claim set, and subsequently, particularly preferred embodiments of the invention are described.

[0009] workpiece

[0010] For the purposes of this patent application, a workpiece is a component that undergoes laser processing to create a weld pattern, weld path, or individual weld points. The workpiece serves as a carrier for the laser process and is designed to absorb the applied laser energy and convert it into heat in a controlled manner to create a molten zone that enables a permanent bond between materials. The workpiece can be made of a single material or composed of multiple layers or components that are bonded together by the laser process. Preferably, the workpiece is made of metallic materials, as these are particularly well-suited for laser processing due to their thermal and physical properties. Materials such as steel, aluminum, or copper are especially advantageous because they efficiently absorb the laser energy, thereby enabling stable welds.In an alternative embodiment, the workpiece can also consist of non-metallic materials, provided these are suitable for laser processing. Composite materials or plastics, for example, which can also be processed using special laser methods, could be considered.

[0011] Regarding the design of the workpiece, various embodiments are conceivable. The workpiece can either be a flat plate or have more complex three-dimensional geometries, as found in industrial applications such as the automotive industry, aerospace, or electronics manufacturing.

[0012] Welding pattern

[0013] For the purposes of this patent application, a weld pattern is the structure created by the action of one or more laser beams on a workpiece, which results in the joining of materials along a defined geometry. A weld pattern can take on various forms, such as a continuous weld path, a series of weld spots, or a combination of both. It represents the visible and functional weld joint that is created by the controlled melting and subsequent solidification of the material.

[0014] The primary function of the welding pattern is to create a permanent and durable bond between two or more material parts. Laser energy input into the material creates a localized weld pool, which, upon solidification, forms a weld seam or weld point. The geometry and design of the welding pattern are determined by the arrangement and application of the laser beams. Advantageously, the welding pattern can be designed to optimally meet the mechanical and thermal requirements of the specific application. Preferably, the welding pattern is generated without relative movement between the laser beam and the workpiece, resulting in higher precision and a more homogeneous structure of the weld pattern.

[0015] The formation of the weld pattern depends primarily on the laser beam geometry used and process parameters such as power and pulse duration. Using multiple laser beams or splitting the original laser beam results in several parallel or overlapping weld seams or spots, which together form the weld pattern. The parallel or synchronized application of the beams allows for controlled manipulation of the weld pool, leading to a uniform energy distribution and a stable welding process.

[0016] Origin laser beam

[0017] For the purposes of this patent application, an originating laser beam is a continuous or pulsed laser beam generated by a laser source, which, before being applied to the workpiece, is either split into several partial beams or transformed into a continuous beam profile. The originating laser beam represents the fundamental energy source for the entire processing operation and serves as the starting point for further beam guidance and beam splitting.

[0018] The original laser beam is preferably provided by a laser source, advantageously using laser powers in the range of 20 kW to 100 kW or more to ensure efficient processing of workpieces of different sizes and material properties.

[0019] The original laser beam is preferably generated using a fiber or disk laser source, wherein the beam is advantageously guided through suitable optics that make it possible either to split the beam into several partial beams or to convert it into a continuous beam profile.

[0020] For the purposes of this patent application, a laser beam is coherent electromagnetic radiation originating from a source laser beam and generated by stimulated emission in a laser source. The source laser beam constitutes the primary energy source and is preferably further processed before striking the workpiece, for example by optical elements, to form one or more laser beams. Advantageously, the source laser beam is split into several partial beams by beam splitters or optical modulators, which are then applied simultaneously to the workpiece to generate the weld pattern(s). Each laser beam derived from the source laser beam retains its coherent nature and high beam quality, thus enabling precise energy transfer. This division makes it possible to process multiple areas of the workpiece simultaneously and thereby increase the efficiency of the welding process.

[0021] It is also possible for multiple laser beams to originate from multiple source laser beams. In this case, each source laser beam is generated from a separate laser source and then preferably processed into multiple laser beams using suitable optical elements. If no optical elements such as beam splitters are used, the laser beam can also be applied to the workpiece in its original form, which advantageously results in direct and unaltered energy transfer. This can be particularly useful in applications where a high energy density is required to achieve deep and precise penetration of the material.This flexibility makes it possible to adapt the process to different processing requirements and offers the possibility of either processing several areas simultaneously by splitting the original laser beam or concentrating high energy densities on specific areas of the workpiece by directly using the original laser beam.

[0022] Advantageous embodiments of the invention

[0023] According to a preferred embodiment of the invention, a plurality of the pulsed laser beams, preferably all pulsed laser beams, are split from a common source laser beam before striking the workpiece. This leads to better energy utilization, as the output power of a single laser is optimally distributed. Furthermore, avoiding multiple separate laser sources reduces the acquisition and operating costs of the laser system. This contributes to economic optimization and makes the process more cost-effective in industrial applications as well.

[0024] According to an advantageous embodiment of the invention, the weld pattern can be a weld bead or a section thereof. For the purposes of this patent application, a weld bead is a continuous or segmented connection created by melting and subsequently solidifying the material on the surface of a workpiece using laser beams. The weld bead serves to create a strong connection between individual workpiece parts or to reinforce specific areas of the workpiece by forming a durable and tight seam with the molten material after solidification. The fact that the weld pattern is a weld bead or a section thereof offers the advantage that both entire weld bead sections and partial sections can be processed efficiently. This allows for flexible adaptation of the process to different workpiece geometries and requirements.Especially with complex welding patterns, the welding process can be precisely controlled, improving the quality and precision of the weld. This makes the process particularly suitable for applications that place high demands on weld accuracy, such as in electronics manufacturing.

[0025] According to a further preferred embodiment of the invention, the spacing of the pulsed laser beams can also be at least 20%, preferably at least 100%, of the beam width perpendicular to the weld path direction. By precisely positioning the laser beams at a specific distance from one another, the heat distribution on the weld path is selectively influenced. This contributes to controlling the melt pool dynamics and reduces the risk of material deformation or damage. The defined spacing of the pulsed laser beams thus allows for targeted control and stabilization of the melt pool dynamics, thereby reducing uncontrolled melting movements such as turbulence. Particularly when processing sensitive or thin materials, this precise control of the melt pool dynamics results in a more stable weld and minimizes the risk of defects such as spatter or porosity.This property contributes to an overall higher quality and reliability of the welded joint, as the thermal and mechanical stresses are distributed more evenly across the material.

[0026] It is further preferred that the optical axes of the laser beams are arranged parallel or at an angle of less than 3° to each other. Arranging the optical axes of the laser beams parallel or at a minimal angle to each other offers the advantage of a uniform energy distribution along the weld path. This uniform energy distribution reduces the risk of local overheating or uneven material melting, resulting in homogeneous weld quality and consistent weld quality across the entire weld length. The precise focus of the beams also enables higher welding speeds and improves the efficiency of the process. Furthermore, the parallel alignment of the beams minimizes energy loss, which reduces energy consumption and lowers operating costs.Especially in demanding applications where high precision and repeatability are required, this property makes a crucial contribution to a robust and reliable welding process.

[0027] Furthermore, according to another advantageous embodiment of the invention, the welding pattern may comprise a plurality of non-contacting weld points. Generating a plurality of non-contacting weld points offers the advantage that the welding process can be carried out with high precision without any overlap of the weld points. This is particularly advantageous when machining sensitive or small components, as is the case, for example, in electronics manufacturing. Moreover, it enables fast and efficient machining of workpieces with complex geometries, since the points can be welded independently of one another.It is also possible that the object of the invention is achieved by a method for laser processing a workpiece in which a weld pattern is generated in the workpiece by means of a pulsed source laser beam, wherein the pulsed source laser beam is transformed into at least one continuous beam profile before striking the workpiece and applied to the workpiece to generate the weld pattern. By transforming the pulsed source laser beam into a continuous beam profile before striking the workpiece, the energy distribution is optimized, which enables a uniform and stable weld seam. This improves the quality of the weld seam, particularly when processing workpieces that are sensitive to heat. In addition, the continuous beam profile controls the melt pool dynamics, thereby preventing spatter and defects in the weld seam.

[0028] For the purposes of this patent application, a beam profile is the geometric shape of the laser beam as it strikes the workpiece in a planar fashion and is distributed over a defined area, in contrast to individual laser beam points, which only generate point-like energy inputs at specific locations. The beam profile describes the spatial extent of the laser beam on the workpiece surface, and it can have a continuous or uniformly distributed shape, such as circular, rectangular, or elliptical, thus processing a larger area simultaneously.

[0029] Unlike laser beam points, which generate only locally limited energy inputs and are often used for spot welding, the beam profile is designed for the uniform and controlled irradiation of a larger area. This enables a uniform energy distribution across the entire processed area, which is particularly advantageous when producing weld seams. A beam profile allows large-area weld patterns to be generated in a single step. Preferably, the beam profile is shaped to correspond to the contour of the desired weld seam to enable precise and efficient processing. Advantageously, the invention can also be further developed such that the original laser beam is transformed into several continuous beam profiles and applied simultaneously to the workpiece to generate the weld pattern.This enables the simultaneous processing of multiple areas of the workpiece, resulting in a significant reduction in processing time. Furthermore, the flexibility of the process is increased, as multiple weld paths can be generated in parallel. This is particularly useful in automated manufacturing processes where a high production rate is required.

[0030] Furthermore, the invention can be further developed such that the welding pattern is generated with a single laser pulse. Generating the welding pattern with only one laser pulse significantly reduces the process time, as multiple pulses are not required. This increases the efficiency of the process and reduces energy consumption, since the required laser energy is concentrated into a single pulse. In addition, the risk of thermal stresses in the workpiece is minimized, leading to improved weld quality and a reduction in material deformation.

[0031] In a further preferred embodiment of the invention, the weld pattern can also be generated at least partially, preferably completely, without any relative movement between the laser beams or the beam profile and the workpiece. This results in a more precise weld seam, since no mechanical movements of the workpiece or the laser are required that could lead to inaccuracies. Furthermore, the process speed is increased because the welding process can be carried out in one step without the need for continuous adjustment of the beam position.

[0032] It can also be advantageous to further develop the invention such that the pulsed source laser beam is operated with pulse durations in the range of 100 ps to 500 ms, particularly 1 ms to 100 ms. The use of pulsed lasers with variable pulse durations offers the advantage that the process can be flexibly adapted to different materials and welding requirements. Particularly with thicker materials or those with high thermal conductivity, a longer pulse duration enables a deeper and more stable weld, while shorter pulses can be used for thinner materials. This improves the versatility of the process and increases process control. Furthermore, the ability to operate the pulsed source laser beam with variable pulse durations offers the advantage of optimal control of the melt pool dynamics.By precisely adjusting the pulse duration to the specific material and welding requirements, the weld pool becomes calmer and more stable, significantly reducing undesirable effects such as spatter, porosity, or material ejection. A stable weld pool also ensures even energy distribution, which improves weld quality and minimizes the risk of defects or flaws.

[0033] It is also advantageous if the original laser beam or one of the laser beams, preferably a plurality of the laser beams, and most preferably all laser beams, has a laser power >20 kW, particularly >50 kW, and most particularly >100 kW. The use of a high laser power of over 20 kW offers the advantage that even large workpieces or materials with high thermal conductivity can be processed efficiently. This significantly reduces the processing time and enables fast and precise manufacturing, even with demanding materials such as steel or aluminum. Furthermore, the higher power leads to deeper penetration of the material, which increases the strength and quality of the welds. The use of high laser power, especially over 20 kW, also offers the advantage that large path contours can be processed efficiently and in a shorter time.The increased performance allows a larger amount of energy to be transferred to the workpiece simultaneously, making it possible to produce even wide or long welds in a single step.

[0034] According to a further preferred embodiment of the invention, the original laser beam and / or laser beams are guided through a 2-in-1 or 3-in-1 fiber, generating two or three focus zones, each with a core beam and one or two ring beams. Using a 2-in-1 or 3-in-1 fiber to generate multiple focus zones offers the advantage of enabling different welding processes to be performed simultaneously. This allows for more efficient processing of the workpiece, as different areas can be welded at the same time. Furthermore, the combination of core and ring beams improves weld quality because the energy distribution is better controlled.

[0035] In this context, the invention can also advantageously be designed such that the core jet has a higher intensity than the ring jet(s). The higher intensity of the core jet compared to the ring jets results in a more stable weld, as the main energy is focused on the central area of ​​the weld bead. This leads to a deeper and stronger weld joint, while the outer ring jets help to stabilize the weld pool and minimize defects such as spatter or porosity. The higher intensity of the core jet compared to the ring jets also stabilizes the so-called keyhole during the welding process. The central focus of the energy on the keyhole ensures that it remains constantly open and does not collapse throughout the entire welding process.This results in a uniform penetration of the material and improves the weld quality by preventing defects such as pores or air inclusions.

[0036] It is also advantageous if the beam parameter product of the core beam is ≤32 mm*mrad, particularly ≤6 mm*mrad, and the beam parameter product of the ring beam(s) is ≤60 mm*mrad, particularly ≤20 mm*mrad. Optimizing the beam parameter product of the core and ring beams offers the advantage of a particularly precise and uniform weld. A lower beam parameter product ensures focused and stable energy input, resulting in narrower and more aesthetically pleasing welds. This is particularly beneficial for applications requiring high weld quality. Furthermore, the optimized beam parameter product enables high processing speeds. The focused energy input allows for more efficient material penetration, thus accelerating the welding process.This not only contributes to a reduction in overall process time, but also to increased productivity, especially in industrial applications where high cycle times are required.

[0037] Furthermore, it is preferred that a camera-based image processing system be used to detect the workpiece position and correct the laser beam position. Using a camera-based image processing system to detect the workpiece position and correct the laser beam position increases the accuracy of the welding process. This reduces tolerances and enables more precise positioning of the laser beam, resulting in improved weld quality. In addition, process reliability is increased because misalignments can be detected and corrected early.

[0038] The object of the invention is further also achieved by a laser processing system for laser processing of a workpiece, comprising a radiation source for providing a pulsed source laser beam, optics for splitting and / or shaping the source laser beam, and a machine control for controlling the radiation source and the optics, wherein the machine control is configured such that the pulsed source laser beam is split into a plurality of laser beams by the optics before it hits the workpiece, and the laser beams are applied to the workpiece simultaneously to generate the welding pattern.

[0039] For the purposes of this patent application, a laser processing system is a device used to generate and control one or more pulsed laser beams for processing workpieces by laser welding. Such a system comprises essential components such as one or more radiation sources, optics for shaping and focusing the laser beams, and a machine control system for precisely regulating the entire welding process.

[0040] The laser beam source, preferably a fiber or disk laser source, supplies the necessary energy in the form of pulsed radiation to create the weld pattern in the workpiece. Advantageously, the laser beam is shaped by the optics to generate multiple beam profiles or partial beams that are applied to the workpiece simultaneously. The optics can use a 2-in-1 or 3-in-1 fiber, or a so-called rectangular fiber or a fiber with a square cross-section, to create multiple focus zones, each consisting of a central core beam and one or more ring-shaped beams. This ensures uniform energy distribution and stable weld pool dynamics, guaranteeing a precise and high-quality weld.

[0041] The machine control system performs the central task of coordinating the laser beam source and the optics, ensuring that the laser beams are precisely directed onto the desired welding path or pattern and that their intensity and geometric shape are accurately controlled. Ideally, the laser processing system features integrated image processing, enabling the monitoring of the workpiece and weld position and real-time corrections to the laser position. This real-time monitoring ensures optimal process control and significantly improves the quality of the weld.

[0042] For the purposes of this patent application, an optic is a technical element or assembly used to shape, direct, and focus the laser beam onto the surface of the workpiece. The optic can be implemented in various embodiments, depending on the specific requirements of the welding process. One advantageous embodiment involves the use of a beam splitter, such as an optical wedge, a diffractive optical element (DOE), or a refractive optical element (ROE). These beam splitters generate at least two or more laser beams that are simultaneously applied to the surface of the workpiece to achieve a uniform energy distribution, thereby increasing process stability and improving welding speed.

[0043] Preferably, scanner optics with an imaging ratio of 1:1 to 5:1, particularly between 2:1 and 3:1, can be used. These optics enable precise control of the laser beam along the weld seam, thus contributing to the accurate guidance of the weld pool. Alternatively, a "flying optic" operating with the same imaging ratios can be used. This optic is characterized by its high flexibility and allows for quick and precise adaptation of the laser beam to complex workpiece geometries, which is particularly advantageous in demanding welding processes.

[0044] The integrated machine control system in the laser processing unit splits the original laser beam into multiple laser beams and applies them simultaneously to the workpiece, enabling efficient and uniform processing of the weld path. This results in the weld path being partially or completely illuminated, significantly reducing the number of laser pulses required and thus shortening the overall process time. Since multiple beams act simultaneously, the heat distribution becomes more uniform, leading to improved control and stabilization of the weld pool dynamics. This contributes to weld pool stabilization, reduces spatter formation, and improves weld quality. Furthermore, simultaneous processing allows for higher welding speeds without compromising precision or joint strength.

[0045] The object of the invention can also be achieved by a laser processing system for laser processing of a workpiece, comprising a radiation source for providing a pulsed source laser beam, optics for splitting and / or shaping the source laser beam, and a machine control for controlling the radiation source and the optics, wherein the machine control is configured such that the pulsed source laser beam is transformed by the optics into at least one continuous beam profile before it strikes the workpiece and is applied to the workpiece to generate the weld pattern. The transformation of the source laser beam into a continuous beam profile before application to the workpiece enables a uniform distribution of energy over the entire weld path.This results in a more uniform weld seam and reduces the likelihood of defects or material damage. Furthermore, it allows the weld path to be partially or completely illuminated in a single step, reducing the number of pulses required and thus significantly shortening the processing time. Uniform irradiation also stabilizes the weld pool dynamics by preventing unwanted turbulence, leading to a high-quality weld seam. This precise control of energy input enables more efficient and faster processing, especially for complex or large weld patterns.

[0046] The invention will now be explained in more detail with reference to figures, without limiting the general concept of the invention.

[0047] It shows:

[0048] Figure 1 shows a first embodiment of the method according to the invention in a schematic representation using a welding path formed from several pulsed laser beams.

[0049] Figure 2 shows a second embodiment of the method according to the invention in a schematic representation based on a welding pattern formed from several pulsed and spaced-apart laser beams.

[0050] Figure 3 shows a third embodiment of the method according to the invention in a schematic representation based on a welding path formed from several pulsed beam profiles.

[0051] Figure 4 shows a first embodiment of a laser processing system in a schematic representation,

[0052] Figure 5 shows a second embodiment of a laser processing system in a schematic representation.

[0053] Figure 6 shows a third embodiment of a laser processing system in a schematic representation. With reference to Figure 1, a method for laser processing a workpiece 1 is explained in more detail, in which a weld pattern 2 is generated in the workpiece 1 by means of a plurality of pulsed laser beams 4. Technically, this allows the laser beams 4 to strike the workpiece 1 simultaneously, which leads to a significant reduction in welding time, since several beams 4 process the weld path 5 at the same time and thus fewer pulses are required. The simultaneous application of the beams 4 also stabilizes the weld pool, as the heat is distributed evenly, thereby preventing spatter and material ejection.

[0054] In the illustrated embodiment, the pulsed laser beams 4 are split from a common source laser beam 3 before striking the workpiece 1. This enables precise control of the energy input, since the source laser beam 3 is distributed into several partial beams 4, resulting in a particularly uniform weld seam. The weld pattern 2, which in this case is a weld track 5 or a section thereof, is thus produced with high precision, ensuring a uniform and robust connection.

[0055] The spacing 6 of the pulsed laser beams 4, which is at least 20%, preferably 100%, of the beam width 8 perpendicular to the welding path direction 7, ensures that the energy is distributed uniformly along the weld path. The parallel or nearly parallel alignment of the optical axes of the laser beams 4, at an angle of <3°, contributes to the uniform penetration of the beams 4 into the material, thus creating a homogeneous weld. This improves the stability of the weld pool and prevents local overheating.

[0056] Figure 1 further shows that the source laser beam 3 and / or the laser beams 4 are guided through a 2-in-1 fiber, thereby generating two focus zones 12. These consist of a central core beam 13 with higher intensity and a ring beam 14 with lower intensity. The higher intensity of the core beam 13 enables a deep and stable weld, while the ring beam 14 controls the weld pool dynamics and stabilizes the keyhole. The beam parameter product of the core beam 13 is ≤32 mm*mrad, preferably ≤6 mm*mrad, while that of the ring beam 14 is ≤60 mm*mrad, preferably ≤20 mm*mrad, thereby further improving the focus and precision of the weld.

[0057] Figure 2 shows that the weld pattern 2 can also consist of a plurality of non-contacting weld points 9a, 9b, 9c. These weld points 9 are used, for example, for the electrical contacting of components on circuit boards. The use of several independent weld points 9 enables precise machining of components with fine structures, which is particularly advantageous in electronics manufacturing.

[0058] Figure 3 shows a variant of the process in which the weld pattern 2 is generated using a pulsed source laser beam 3. Before striking the workpiece 1, the laser beam is transformed into at least one continuous beam profile 10, which is applied to the workpiece to generate the weld pattern. This transformation ensures a uniform energy distribution across the entire weld area, resulting in a homogeneous weld seam. The cuboid-shaped beam profiles 10a, 10b, 10c shown in Figure 3 are aligned along the weld path 5 and enable the simultaneous processing of several sections of the workpiece 1.

[0059] In this variant as well, the original laser beam 3 can be transformed into several continuous beam profiles 10 in order to process the workpiece 1 simultaneously at different points. This not only increases the speed of the process, but also improves the precision and homogeneity of the welds, since the energy is distributed evenly across the processed surfaces.

[0060] A particular advantage is that the welding patterns shown in Figures 1-3 can each be generated with only a single laser pulse. This significantly reduces the number of pulses required and leads to a substantial reduction in process time. Since no relative movement between the laser beams 4 or the beam profile 10 and the workpiece 1 is necessary, the welding process is carried out with exceptional precision and uniformity, further improving the quality of the welds. The original laser beam 3 is operated with pulse durations in the range of 100 ps to 500 ms, particularly 1 ms to 100 ms, allowing for flexible adaptation of the process to different materials and requirements. By using a laser power of more than 20 kW, preferably more than 50 kW, even thicker materials can be processed efficiently without compromising weld quality.

[0061] To ensure precise processing, a camera-based image processing system is used that detects the position of workpiece 1 and corrects the laser position accordingly. This guarantees optimal alignment of the laser beam and minimizes possible deviations during the welding process.

[0062] Figure 4 shows a laser processing system 20 comprising a radiation source 21, optics 22 for splitting or shaping the original laser beam 3, and a machine control 23. This machine control is configured such that the laser beam is split into several laser beams 4 before impacting the workpiece 1, which are applied simultaneously to generate the weld pattern 2. Alternatively, the machine control 23 can also transform the original laser beam 3 into a continuous beam profile 10, which is used for the uniform processing of the weld path 5.

[0063] Figure 5 shows an extended embodiment of the laser processing system 20, in which two radiation sources 21a and 21b are used to generate laser beams 4 from two different source beams 3a and 3b to produce the welding pattern 2.

[0064] Finally, Figure 6 shows an embodiment of the laser processing system in which three source beams 3a, 3b, 3c from three different radiation sources 21a, 21b, 21c are directed directly onto the workpiece. In this embodiment, the use of an optic 22 for beam splitting is omitted, which enables the direct application of the beams 3, 4 to the workpiece 1 and supports particularly fast and flexible processing. The invention is not limited to the embodiments shown in the figures. The preceding description should therefore be considered explanatory rather than limiting. The following claims are to be understood as meaning that a mentioned feature is present in at least one embodiment of the invention. This does not preclude the presence of further features.If the patent claims and the preceding description define 'first' and 'second' features, this designation serves to distinguish between two similar features without establishing a hierarchy.

[0065] List of reference signs

[0066] 1 workpiece

[0067] 2 welding patterns

[0068] 3 Origin laser beam

[0069] 4 Laser beam

[0070] 5 Welding membrane

[0071] 6 distance

[0072] 7 Welding direction

[0073] 8 beam width

[0074] 9 welding points

[0075] 10 Beam profile

[0076] 12 focus zones

[0077] 13 Core beam

[0078] 14 ring rays

[0079] 20 laser processing systems

[0080] 21 Radiation source

[0081] 22 Optics

[0082] 23 Machine control

Claims

Claims 1. Method for laser processing of a workpiece (1) in which a welding pattern (2) is generated in the workpiece (1) by means of a plurality of pulsed laser beams (4), characterized in that the pulsed laser beams (4) are applied to the workpiece (1) simultaneously with the generation of the welding pattern (2).

2. Method according to claim 1, characterized in that a plurality of the pulsed laser beams (4), preferably all pulsed laser beams (4) are split from a common origin laser beam (3) before striking the workpiece (1).

3. Method according to claim 1 or 2, characterized in that the welding pattern (2) is a weld track (5) or a section of a weld track (5).

4. Method according to one of claims 1-3, characterized in that the distance (6) of the pulsed laser beams (4) is at least 20%, preferably at least 100% of the beam width (8) extending vertically to the welding path direction (7).

5. Method according to one of claims 1-4, characterized in that the optical axes of the laser beams (4) are arranged parallel or at an angle of <3° to each other.

6. Method according to one of the preceding claims, characterized in that the welding pattern (2) comprises a plurality of welding points (9) that are not in contact with each other.

7. Method for laser processing of a workpiece (1) in which a welding pattern (2) is generated in the workpiece (1) by means of a pulsed source laser beam (3), characterized in that the pulsed source laser beam (3) is transformed into at least one continuous beam profile (10) before hitting the workpiece (1) and is applied to the workpiece (1) to generate the welding pattern (2).

8. Method according to claim 7, characterized in that the pulsed source laser beam (3) is transformed into a plurality of continuous beam profiles (10) before impacting the workpiece (1 ) and is applied simultaneously to the workpiece (1 ) to generate the welding pattern (2).

9. Method according to one of the preceding claims, characterized in that the welding pattern (2) is generated with a laser pulse.

10. Method according to one of the preceding claims, characterized in that the welding pattern (2) is produced at least partially, preferably completely, without any relative movement between the laser beams (4) or the beam profile (10) and the workpiece (1).

11. Method according to one of the preceding claims, characterized in that the pulsed source laser beam (3) is operated with pulse durations in the range of 100 ps to 500 ms, in particular 1 ms to 100 ms.

12. Method according to one of the preceding claims, characterized in that the original laser beam (3) or one of the laser beams (4), preferably a plurality of the laser beams (4), particularly preferably all laser beams (4) has a laser power >20 kW, in particular >50 kW, in particular >100 kW 13. Method according to one of the preceding claims, characterized in that the original laser beam (3) and / or the laser beams (4) is / are guided through a 2in 1 or 3in1 fiber, so that two or three focus zones (12) are generated, which have a core beam (13) and one or two ring beams (14).

14. Method according to claim 13, characterized in that the core beam (13) has a higher intensity than the ring beam(s) (14).

15. Method according to claim 13 or 14, characterized in that the beam parameter product of the core beam (13) is <=32 mm*mrad, in particular <= 6 mm*mrad, and the beam parameter product of the ring beam(s) (14) is <=60 mm*mrad, in particular <= 20 mm*mrad.

16. Method according to one of the preceding claims, characterized in that a camera-based image processing system is used to detect the position of the workpiece (1) and to correct the position of the laser beam (5).

17. Laser processing system (20) for laser processing of a workpiece (1), comprising a radiation source (21) for providing a pulsed source laser beam (3), optics (22) for splitting and / or shaping the source laser beam (3), and a machine control (23) for controlling the radiation source (21) and the optics (22), characterized in that the machine control (23) is configured such that the pulsed source laser beam (3) is split into a plurality of laser beams (4) by the optics (22) before striking the workpiece (1), and the laser beams (4) are applied to the workpiece (1) simultaneously to generate the welding pattern (2).

18. Laser processing system (20) for laser processing of a workpiece (1), comprising a radiation source (21) for providing a pulsed source laser beam (3), optics (22) for splitting and / or shaping the source laser beam (3), and a machine control (23) for controlling the radiation source (21) and the optics (22). characterized in that the machine control (23) is configured such that the pulsed origin laser beam (3) is transformed by the optics (22) into at least one continuous beam profile (10) before impacting the workpiece (1) and applied to the workpiece (1) to generate the welding pattern (2).

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