Device, system and method for welding two workpieces by means of a filler material and a laser beam
Patent Information
- Application Number
- PCT/EP2026/054592
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2025-10-30
- Filing Date
- 2026-02-19
- Publication Date
- 2026-08-27
Smart Images
Figure EP2026054592_27082026_PF_FP_ABST
Abstract
Description
[0001] Precitec GmbH & Co. KG, Case: PR 986 WO
[0002] Device, system and method for welding two workpieces using a laser beam
[0003] The present invention relates to a laser processing head for welding two workpieces by means of a laser beam, a system comprising the laser processing head and a corresponding method.
[0004] Technical background
[0005] To weld two workpieces without overlap using a laser beam, a wire is conventionally fed into the weld joint, for example, to at least partially fill a gap between the two workpieces. The two workpieces and / or the wire are irradiated by a focused, high-power laser beam and melted at a processing point, also called the tool center point (TCP). The laser welding head's alignment can be adjusted by the wire contacting one of the workpieces or the weld joint. The wire provides tactile feedback to the laser welding head, which is then used to control the welding of the two workpieces.
[0006] The challenge in the automated welding of two workpieces lies in the fact that the workpieces can each be unique, meaning that, for example, the weld joint and / or the gap between the two workpieces can vary, and / or surface inspection is required to ensure sufficient weld quality. Furthermore, the tactile wire feed allows for monitoring of the weld joint geometry.
[0007] However, the close, contact-related wire guidance has several disadvantages. The high temperatures required for welding can lead to rapid heating of the wire feed device and potentially the laser welding head, especially with wire materials that have good thermal conductivity. Therefore, a particularly robust wire feed device or laser welding head would be needed for such welds, particularly since their wear and tear can be significantly higher compared to welding workpieces containing steel. Precitec GmbH & Co. KG, Case: PR 986 WO
[0008] To reduce the heating of the wire feed device and possibly the laser welding head, additional cooling may be required, which can significantly increase the complexity of the laser welding head.
[0009] Furthermore, tactile feedback can only reflect the geometry of the weld joint with a delay, i.e., after the wire has made contact with the weld joint. To still be able to react to the tactile feedback during welding, the processing speed may need to be reduced.
[0010] Summary of the invention
[0011] Therefore, there is a need for a laser processing head, a corresponding system, and a corresponding process that at least partially overcome the aforementioned disadvantages of tactile wire guidance when welding two workpieces. Furthermore, there is a need for a laser processing head, a system, and a corresponding process with adaptive filler material feed when welding two workpieces.
[0012] At least one of the aforementioned technical problems is solved by a laser processing head, the system, and / or the method according to the respective independent claim. Further embodiments of the laser processing head, the system, and / or the method are specified in the respective dependent claims.
[0013] According to one aspect of the present invention, a laser processing head for welding two workpieces is provided. The laser processing head comprises: an entry port for coupling the laser beam into the laser processing head; a focusing optic for directing the laser beam onto the workpieces; a feed device for the non-contact feeding of a welding filler material, wherein the feed device is arranged at a distance from a beam axis of the laser beam; a first observation device, which is arranged at a distance from the beam axis of the laser beam and is configured to detect a first observation signal from an area in the processing direction in front of the laser beam; and a control device, which is configured to control and / or regulate the welding based on the first observation signal.
[0014] According to another aspect of the invention, a system for welding two workpieces is provided. The system comprises a laser source, a linear An-Precitec GmbH & Co. KG, Case: PR 986 WO
[0015] a linear drive axis for weld seam tracking; and a laser processing head according to one aspect of the invention, wherein the laser processing head is coupled to the laser source and is arranged on the linear drive axis.
[0016] According to a further aspect of the invention, a method for welding two workpieces is provided. The method comprises: shining a laser beam onto the workpieces to weld them; non-contact feeding of a welding filler material for welding the workpieces by means of a feeding device arranged at a distance from a beam axis of the laser beam; detection of a first observation signal from an area in the processing direction in front of the laser beam by means of a first observation device arranged at a distance from the beam axis of the laser beam; and control and / or regulation of the welding, in particular the shining of the laser beam and / or the feeding of the welding filler material, based on the first observation signal.
[0017] The method can be carried out or implemented by a laser processing head according to one aspect of the invention and / or by a system according to one aspect of the invention.
[0018] The invention is based on the core concept of supplying the welding filler material to the welding process without contact and using a first observation signal from a first observation device to control and / or regulate the welding process. The first observation device can detect a region in the lead-up to the welding position. This allows predictive feedback for the welding process to be determined based on the first observation signal and / or the supply of the welding filler material to be adaptively adjusted. Due to the contactless supply of the welding filler material, the material can be supplied regardless of its thermal conductivity. Even with welding filler materials containing, for example, aluminum, there is therefore no increased risk of the supply device overheating.
[0019] The laser processing head, system and / or process may also have one or more of the following features:
[0020] The input port can be a socket for a fiber optic connector of a laser source. The input port can be configured to connect a laser source to the laser processing head. Precitec GmbH & Co. KG, Case: PR 986 WO
[0021] The focusing optics can be configured to focus the laser beam along its optical axis above, on, or below the processing position. The focusing optics can comprise one or more lenses. The focusing optics can have a focus length in the range of 250 to 500 mm, preferably 300 to 400 mm, and particularly preferably 300 mm.
[0022] The feed device is positioned at a distance from the laser beam axis. The feed device has no direct or indirect contact with any of the workpieces or the joint. Furthermore, the feed device is designed for non-contact feeding of the welding filler material, meaning that the welding filler material is fed in such a way that it does not come into direct or indirect contact with any of the workpieces or the joint. Therefore, the feed device cannot provide any tactile feedback.
[0023] The feeding device can be configured to feed the welding filler material at an angle to the beam axis of the laser beam. The angle can be in a range of 30 to 80 degrees, preferably 40 to 50 degrees, or 45 degrees or more. The feeding device can feed the welding filler material along a predetermined feeding direction. The feeding direction and the beam axis of the laser beam can lie in the same plane. The feeding direction can form an angle with the processing direction. The feeding direction and the processing direction can lie in a plane that contains the beam axis of the laser beam. The feeding device can be configured to feed the welding filler material to a position of the incident laser beam. The feeding device can be configured to feed the welding filler material at a distance from the two workpieces and / or from the joint.to provide or feed the welding filler material into the gap between the two workpieces. The feeding device can be configured to feed the welding filler material directly into the laser beam.
[0024] The control device can be configured to control and / or regulate components of the laser processing head and / or the laser processing system. The control device can be decentralized. In other words, the control device can be composed of or comprise control units from various components of the laser processing head and / or an external control unit.
[0025] The first observation device is positioned at a distance from the beam axis of the laser beam. An optical axis of the first observation device can form an angle with the beam axis of the laser beam. In particular, the first observation device can be considered non-coaxial. The optical axis of the first observation device Precitec GmbH & Co. KG, Case: PR 986 WO
[0026] can be located in a plane containing the beam axis of the laser beam. The first observation device or control device can be configured to find a position of a joining point in advance (i.e., in the processing direction ahead of the laser beam), for example, based on the first observation signal.
[0027] The optical axis of the first observation device, the feed direction of the feed device, and the beam axis of the laser beam can lie in the same plane. The first observation device can be arranged in the lead-up to the laser processing head, and the feed device can be arranged in the lead-up or the trailing-up to the laser processing head.
[0028] The first observation device can furthermore be arranged at a distance from the feed device, in particular in the circumferential direction around the beam axis of the laser beam or around the laser processing head. The optical axis of the first observation device can form an angle with the feed direction of the feed device. In particular, a plane in which the optical axis of the first observation device and the beam axis of the laser beam lie, and a plane in which the feed direction and the beam axis of the laser beam lie, can be arranged at an angle to or perpendicular to each other.
[0029] The first observation signal can replace and extend the tactile feedback from previously known laser welding heads.
[0030] Welding the two workpieces together can create a butt joint, a butt joint, a T-joint, a flanged joint, and / or a corner joint. The two workpieces can be positioned for welding in a butt joint, T-joint, or corner joint. The welding process can include laser beam injection and / or the application of filler material.
[0031] The area in the processing direction in front of the laser beam can be a region in the lead-up (of the processing position). The processing position can be the TCP (Process Transfer Point). The area in the processing direction in front of the laser beam can be located between 40 and 100 mm in front of the laser beam or the processing position, preferably between 50 and 70 mm in front of the laser beam or the processing position.
[0032] The control device can be configured to set at least one process parameter based on the first observation signal, e.g., a laser intensity or -Precitec GmbH & Co. KG, Case: PR 986 WO
[0033] Power, feed rate and / or direction of the welding filler material, focus position of the laser beam, position of the laser beam on the workpieces, irradiation pattern of the laser beam, and / or relative velocity between the workpieces and the laser processing head. This allows the welding process to be adaptively adjusted to the workpieces being welded. For example, the feed of the welding filler material can be reduced or even stopped if the initial observation signal indicates that the gap between the two workpieces at a subsequent processing position is smaller than at the current processing position or even disappears. The control device can be configured to adaptively control the feed device based on the initial observation signal, particularly information about the geometry of the joint at the processing position, i.e.,The control device can be configured to adaptively control the feed of the welding filler material. Alternatively or additionally, the control device can be configured to adaptively control the laser beam's illumination pattern, particularly in combination with the laser power, based on the initial observation signal. The laser beam's illumination pattern can have a predetermined shape. In particular, the laser beam's illumination pattern can have a repeating pattern (e.g., along the joint), such as a sinusoidal, spiral, circular, or sawtooth pattern, or a pattern in the shape of a horizontal figure eight. The control device can be configured to adjust the illumination pattern with respect to its shape, frequency, amplitude, and / or an offset transverse to the processing or feed direction based on the initial observation signal.
[0034] The control device can be configured to control the position of the feed device along at least one direction based on the initial observation signal. The position of the feed device can, in particular, be the position of a nozzle for dispensing or supplying the welding filler material to the feed device. The direction can be a z-direction parallel to the optical axis of the focusing optics. In other words, the z-direction can be defined as the direction parallel to the optical axis of the focusing optics. An x-direction and / or a y-direction can each be defined as a direction perpendicular to the z-direction. The x-direction and the y-direction, together with the z-direction, can define an orthogonal coordinate system. The z-direction can correspond to the incident direction of the laser beam. This direction can be perpendicular to the z-direction.The direction can be an x-direction, for example, a direction parallel to the feed direction of the laser processing head and / or perpendicular to the z-direction. The direction can be a y-direction. (Precitec GmbH & Co. KG, Case: PR 986 WO.)
[0035] The direction of movement can be, for example, transverse to the feed direction of the laser processing head and / or perpendicular to the z-direction. The x-direction and the y-direction can be perpendicular to each other. The control device can be configured, based on the first observation signal, to control the position of the feed device along a combination of at least two directions from the x-direction, the y-direction, and the z-direction.
[0036] The focus position of the laser beam, i.e., its focal position, can be adjustable, for example in a third direction or in the z-direction. Collimation optics can be used to adjust the focus position of the laser beam.
[0037] The position of the incident laser beam can be adjusted perpendicular to the beam direction, for example, in a first and / or second direction or in the x and / or y direction. In particular, an offset of the laser beam perpendicular to the processing direction or perpendicular to a direction of relative movement between the workpieces and the laser processing head can be adjusted. A scanner device can be configured to adjust the position of the incident laser beam in at least one direction perpendicular to the beam direction. The scanner device can further be configured to vary the position of the incident laser beam according to the illumination pattern. The illumination pattern can also be referred to as the scan pattern.
[0038] The laser processing head can include an adjustment device for moving the feed device along at least one direction. The direction can be (only) the x-direction. The direction can be (only) the y-direction. The direction can be (only) the z-direction. The z-direction is preferred to adaptively adjust the weld material feed based on the first observation signal. The adjustment device can include a piezoelectric element and / or an (electric) motor to adjust the position of the feed device.
[0039] The adjustment device can be configured to adjust the position of the feed device in the z-direction and in at least one direction perpendicular to the z-direction. The adjustment device can also be configured to adjust the position of the feed device in a combined direction using at least two directions from the x-direction, the y-direction, and the z-direction.
[0040] The control device can be configured to control the adjustment device based on the deflection of the laser beam by the scanner device. Thus, the feeder Precitec GmbH & Co. KG, Case: PR 986 WO
[0041] The welding filler material is adjusted to the deflection of the laser beam by the scanner device. The control device can be configured to control the adjustment device synchronously with the deflection of the laser beam by the scanner device.
[0042] Laser intensity can include laser power or laser output.
[0043] The first observation device or control device can be set up to determine a distance to the two workpieces to be joined, based on triangulation.
[0044] The triangulation can, in particular, include line triangulation. The first observation device can include a triangulation sensor, a line triangulation sensor, a camera, and / or a grayscale camera.
[0045] The term "triangulation" can refer to distance measurement through angle calculation. A single-beam element of the first observation device can project a point or line of light onto the workpieces. The reflected light strikes a receiving element of the first observation device at a specific angle, depending on the distance. The distance to the workpieces can be determined from the position of the point of light on the receiving element and the distance between the point of light on the beam element and the position of the point of light on the receiving element. The first observation device can have an array of point-beam elements and corresponding receiving elements to determine the distance to the workpieces along a line. Alternatively or additionally, the first observation device can include a scanning element that can project a point of light along a line onto the workpieces.The line of light points on the workpieces can intersect the joint. This allows the first observation device to capture a cross-sectional profile through the joint at the next machining position. Based on this cross-sectional profile, the distance between the workpieces or the size of the gap between them can be determined.
[0046] The first observation signal can include or be a distance signal. The first observation signal can contain information about the geometry of a joint between the two workpieces and / or information about the surface finish of at least one of the two workpieces and / or information about the surface finish of the joint and / or a cross-sectional profile through the joint at a subsequent machining position. The first observation signal is from Precitec GmbH & Co. KG, Case: PR 986 WO.
[0047] The signal can include information about the surface topography of at least one of the two workpieces and / or the joint in the run-up. The surface properties can, for example, include surface topography and / or surface reflectivity.
[0048] The first observation device or control device can be configured to determine the geometry of the joint, e.g., the width of the joint or the gap between the two workpieces, at the next machining position based on the first observation signal. The geometry can be determined from the first observation signal using a predetermined algorithm. The predetermined algorithm can include a trained neural network.
[0049] The first observation device can be located outside the laser processing head on the laser processing head. An optical axis of the first observation device can form an angle with the beam axis of the laser beam.
[0050] The laser processing head may further include a scanner device. The scanner device may be configured to deflect the laser beam along at least one direction or to position the laser beam in a direction perpendicular to the incident beam direction. The scanner device may further be configured to vary or adjust the position of the laser beam according to the incident beam pattern. The control device may further be configured to control the deflection of the laser beam by the scanner device.
[0051] The scanner device can, in particular, comprise or be a galvo scanner device. The scanner device can comprise an ID scanner or a 2D scanner. The scanner device can be configured to periodically deflect the laser beam with a predetermined amplitude and / or speed and / or direction. This can generate a so-called wobble motion of the processing position, for example, a sinusoidal one. Because the laser beam is deflected by the scanner device in at least one direction, in conjunction with a relative movement between the laser processing head and the two workpieces, the laser beam can perform a wobble motion on the two workpieces. This wobble motion of the laser beam allows the workpieces to be reliably welded and a consistently high weld quality to be achieved. The scanner device can also be configured to determine the position of the laser beam on the workpieces.to be adjusted at the joint. Precitec GmbH & Co. KG, Case: PR 986 WO.
[0052] The laser processing head may further include a second observation device. The observation beam path of the second observation device may be at least partially coaxial with the beam path of the laser beam. The second observation device may be configured to determine the position of the laser beam and / or the position of the welding filler material or the position of the welding filler material feed point.
[0053] The observation beam path of the second observation device can be coaxial with the laser beam path and directed towards the workpieces and / or the joint. An observation field of the second observation device can encompass the TCP (contact point), the processing position, a position of the laser beam, and / or the weld seam. The second observation device can be configured to acquire a second observation signal that includes the approach position of the filler material.
[0054] The control device can be configured to adjust the laser beam based on the second observation signal, in particular to deflect and / or shape it. The control device can be configured to control the scanner device based on the second observation signal. The control device can be configured to set a position of the laser beam based on the second observation signal. The control device can be configured to adjust, regulate, and / or control the feed of the welding filler material or the feed device based on the second observation signal. The control device can be configured to coordinate a position of the feed of the welding filler material or a position of the welding filler material and / or a position of the laser beam based on the second observation signal.
[0055] The second observation device may include a triangulation sensor, a line triangulation sensor, a camera and / or a grayscale camera.
[0056] The second monitoring device can further be configured to acquire a second monitoring signal from the machining position and / or during the follow-up to the machining position. The control device can further be configured to determine the quality of the workpiece machining based on the second monitoring signal from the second monitoring device and / or to control the welding of the two workpieces based on the second monitoring signal.
[0057] The second observation signal can include grayscale image data. Small defects in the formed weld seam, such as pores or micropores, can be easily visualized in grayscale image data. (Precitec GmbH & Co. KG, Case: PR 986 WO)
[0058] It is more easily recognized than with a color display. The control device can be configured to process or evaluate the second observation signal using a neural network, for example, to improve the contrast of the second observation signal.
[0059] The laser processing head may further include collimation optics for collimating the laser beam. The collimation optics may be configured to adjust the focus position of the laser beam. The collimation optics may be adjustable. The collimation optics may include an actuator to adjust the position of the collimation optics, or at least a part of them. The collimation optics may include a lens or a group of lenses, which may be configured to collimate the typically divergent laser beam from a laser source. A position (or at least a part of) the collimation optics may be adjustable along a direction parallel to its optical axis and / or along the beam axis of the laser beam. A position of the collimation optics may be adjustable to set the focus position of the incident laser beam.
[0060] The welding filler material can be in wire or powder form. It can include aluminum, copper, steel, and / or stainless steel. In a preferred embodiment, the welding filler material can be a wire.
[0061] Both workpieces can be metallic. At least one of the two workpieces can contain aluminum.
[0062] The control device can be configured to adjust the amount of welding filler material supplied by the feed device based on the initial observation signal. The control device can also be configured to control the feed device to supply more welding filler material, particularly wire, for example, if the initial observation device detects a larger gap between the workpieces than originally specified for welding. This ensures that even the larger gap is adequately filled (gap bridging). The more welding filler material is supplied, the more can be used to fill the gap or joint. The distance between the welding filler material and a focus position of the laser beam at the processing position can be adjusted using the collimation optics.In other words, the control device can be configured to adjust the focus position of the laser beam based on the position of the welding filler material at the processing position, in particular based on the position of the welding filler material along the beam axis of the laser beam. Specifically, a focus position of the laser beam can be based on Precitec GmbH & Co. KG, Case: PR 986 WO.
[0063] The thickness of the wire supplied as welding filler material can be adjusted. The perpendicular distance of the welding filler material to the processing position, for example, the wire height, can be set by the collimation optics. The control device can be configured to set the position of the collimation optics based on the surface topography at the processing position, for example, such that the focus position has a substantially constant distance to the surface of the workpieces.
[0064] The control device can be configured to adjust the feed of the welding filler material, in particular the wire, and / or the focus position of the laser beam when there is a change in height on at least one of the two workpieces and / or a change in the height of the gap or joint, as determined based on the first observation signal. This allows the weld seam to be held in the same position and prevents the welding filler material, in particular the wire, from being welded unevenly. The control device can also be configured to adjust the feed of the welding filler material, in particular the wire, based on an adjustment of the collimation optics position when there is a change in height on at least one of the two workpieces and / or a change in the height of the gap or joint, as determined based on the first observation signal. The relative velocity, i.e.,The processing speed or feed rate of the laser processing head can depend on the application and scenario. The geometry of the joint gap or weld joint and / or its path and / or curvature can also be taken into account by varying the laser power and / or the amplitude and / or frequency of an optional scanner device, thus enabling consistent welding results regardless of tool or workpiece inconsistencies.
[0065] The laser processing head can further include a third observation device, which is arranged on the laser processing head at a distance from the beam axis of the laser beam. The third observation device can be configured to detect an area in the wake of the processing position. The third observation device can include a triangulation sensor, a line triangulation sensor, a camera, and / or a grayscale camera. An optical axis of the third observation device forms an angle with the beam axis of the laser beam. The optical axis of the third observation device can lie in a plane that contains the beam axis of the laser beam. The third observation device can be arranged opposite the first observation device with respect to the laser processing head. In other words, the optical axis of the third observation device and the optical axis of the first observation device can be aligned. Be-Precitec GmbH & Co. KG, Case: PR 986 WO
[0066] The third observation device can be configured to inspect and / or monitor the weld seam after welding. It can also be configured to detect surface properties, particularly the surface topography of the weld seam. Furthermore, it can be configured to generate and provide a third observation signal, such as a distance signal. This signal can contain information about the geometry of the weld seam between the two workpieces and / or information about the surface properties of at least one of the two workpieces and / or the weld seam after welding.
[0067] It is advantageous to provide a third observation device in addition to the first to ensure an unobstructed view of the follow-up phase of the processing position. The field of view of the first observation device may be limited to an area in the lead-up to the processing position. If the field of view of the first observation device also includes the processing position itself, it must be assumed that the feed device and / or the laser processing head obstruct the view of the follow-up phase of the first observation device.
[0068] In conjunction with the third observation device, the second observation device can be configured as a coaxial camera to adjust or monitor the alignment of the feed device or the welding filler material with respect to the processing position or the TCP (thermostatic welding terminal). Furthermore, the second observation device can be configured to monitor and / or control the welding process in the TCP and / or in the (immediate) vicinity of the TCP.
[0069] The control device can further be configured to regulate the welding and / or components of the laser processing head or the laser processing system based on the third observation signal. In particular, the control device can be configured to set at least one process parameter, e.g., a laser intensity or power, a feed rate and / or direction of the welding filler material, a focus position of the laser beam, a position of the laser beam on the workpieces, an irradiation pattern of the laser beam, and / or a relative velocity between the workpieces and the laser processing head. Precitec GmbH & Co. KG, Case: PR 986 WO
[0070] The control device can be configured, in particular, to control or adjust at least one of the following components based on the first observation signal, the second observation signal and / or the third observation signal: at least one of the first, second and third observation devices, the scanner device, the feed device, the collimation optics, the linear drive axis and / or the laser source.
[0071] The laser source can be a continuous wave (CW) laser source. The laser beam can be a continuous wave (CW) laser beam.
[0072] Brief description of the drawings
[0073] The invention is described in detail below with reference to figures.
[0074] Fig. 1 shows a schematic view of a laser processing head for welding two workpieces together using a laser beam according to embodiments of the invention;
[0075] Fig. 2 shows a further schematic view of a laser processing head for welding two workpieces using a laser beam according to embodiments of the invention;
[0076] Fig. 3 shows a further schematic view of a laser processing head for welding two workpieces using a laser beam according to embodiments of the invention;
[0077] Fig. 4 shows a further schematic view of a laser processing head for welding two workpieces by means of a laser beam according to embodiments of the invention;
[0078] Fig. 5 shows a further schematic view of a laser processing head for welding two workpieces using a laser beam according to embodiments of the invention;
[0079] Fig. 6 shows a further schematic view of a laser processing head for welding two workpieces using a laser beam according to embodiments of the invention; Precitec GmbH & Co. KG, Case: PR 986 WO
[0080] Fig. 7 shows a schematic view of a system for welding two workpieces using a laser beam according to embodiments of the invention; and
[0081] Fig. 8 shows a flowchart of a method for welding two workpieces using a laser beam according to embodiments of the invention.
[0082] Detailed description of the drawings
[0083] Corresponding elements and sizes are always designated with the same reference numerals in all figures. Unless otherwise noted, the same reference numerals are used for identical and equivalent elements in the following text. Redundant descriptions of recurring features are avoided. The various embodiments and features of the figures described below are expressly combinable and should not be understood as complete embodiments.
[0084] Figure 1 shows a laser processing head 1 according to one aspect of the disclosure. The laser processing head 1 can be configured to weld two workpieces in a working plane, characterized in Figure 1 by a horizontal line. In the coordinate system 200 in Figure 1, the processing direction is in the x-direction. The two workpieces can be arranged without overlap in the working plane, with a gap or joint between the workpieces that must be adequately filled during welding. The joint can extend in the x-y plane. The joint can have a curved profile.
[0085] To fill the joint, a welding filler material can be supplied. For this purpose, the laser processing head 1 can have a supply device 30. The supply device 30 can be arranged laterally outside the laser processing head 1, spaced apart from the beam axis of the laser beam. The supply device 30 can be configured to supply a welding filler material, in particular a wire, at an angle to the beam axis of the laser beam or to the working plane. For optimal welding results, the supply of the welding filler material and the focal point of the laser beam must each be aligned with the joint. In other words, the welding filler material must be supplied centered on the processing position 90. Precitec GmbH & Co. KG, Case: PR 986 WO
[0086] The laser beam can be supplied via a laser fiber, which is coupled as a laser source 50 to an entry port 10 of the laser processing head 1. The laser beam can be focused by a focusing optic 30 at, above, or below the processing position 90. For welding the workpieces, a high-power laser beam is typically directed onto the workpieces. Furthermore, the laser processing head 1 can have a protective glass, for example, to protect the focusing optic 20.
[0087] The laser processing head 1 can further comprise a first observation device 40. The first observation device 40 can, for example based on triangulation, detect a distance to various measuring points on the workpieces, preferably along a line. Based on the detected distances, a surface finish, in particular a geometry and / or a profile of the joint, can be determined along the measuring points. The first observation device 40 can be configured to provide a first observation signal comprising information about the surface finish and / or geometry of the joint and / or the workpieces. An optical axis of the first observation device 40 can form an angle α with the beam axis of the laser beam.
[0088] The first observation device 40 is configured to detect an area 91 in the processing direction in front of the laser beam, i.e., an area 91 in advance of the processing position. This allows the geometry and / or surface finish of a future processing position to be characterized so that the process, i.e., the welding, can be adapted accordingly. Tactile feedback from the feed device 30 is neither provided nor required.
[0089] The laser processing head 1 can include a control device 60. The control device 60 can be configured to receive the first observation signal from the first observation device 40. Based on the first observation signal, the control device 60 can control and / or regulate the welding. The control and / or regulation of the welding is described in more detail with reference to the method shown in Fig. 8.
[0090] The laser processing head can include an adjustment device 35. The adjustment device 35 can be configured to adjust the feed device 30 in at least one direction x, y, z. The control device 60 can be configured to control the adjustment device 35 based on the first observation signal or to control the feed device 30. (Precitec GmbH & Co. KG, Case: PR 986 WO)
[0091] The adjustment device 35 can be set. The three arrows, arranged in pairs perpendicular to each other and superimposed on the adjustment device 35 in Fig. 1 (and the following figures), indicate possible directions for adjusting the feed device 30. The position of the feed device, in particular the position of a nozzle of the feed device 30, can be adjusted by the adjustment device 35 in exactly one direction from the x-direction, the y-direction, and the z-direction, or any combination thereof.
[0092] Fig. 2 shows a laser processing head 1 according to a further aspect of the disclosure.
[0093] In Fig. 2, the laser processing head 1 is shown in a frontal view, with the x-direction pointing towards the viewer. A joint 93 is visible between the workpieces 94 and 95, which is formed by the addition of welding filler material during welding. In contrast to the laser processing head 1 in Fig. 1, the feed device 30 on the laser processing head 1 in Fig. 2 is not arranged in the processing direction, i.e., along the x-direction on the laser processing head 1, but rather along the circumferential direction of the laser processing head 1, spaced apart from the first observation device 40. The feed device 30 and the first observation device 40 can be arranged on different sides of the laser processing head 1. This allows the field of view of the first observation device 40 to be increased in the direction of the TCP (Cutting Point).In one embodiment, the feed device 30 can be arranged on the laser processing head 1 in the processing direction and the first observation device can be arranged along the circumferential direction of the laser processing head 1 at a distance from the feed device 30.
[0094] Figure 3 shows a laser processing head 1 according to a further aspect of the disclosure. The laser processing head 1 of Figure 3 is based on the laser processing head of Figure 1 and additionally includes a collimation optic 12.
[0095] The collimation optics 12 can comprise one or more lenses configured to collimate the laser beam coupled into the entry port (and supplied, for example, by the laser source 50). Coupling the laser beam into the laser processing head, for example, via an optical fiber, typically results in a slightly divergent laser beam. The laser source 50, shown as a fiber laser in Fig. 3, also usually provides a slightly divergent laser beam due to its aperture. The collimation optics 12 can reduce the coupled diverging beam. (Precitec GmbH & Co. KG, Case: PR 986 WO)
[0096] The laser beam is directed or collimated parallel to the optical axis of the collimation optics 12 or the laser processing head 1.
[0097] The collimation optics 12 can be adjusted along its optical axis (double arrow in Fig. 3), e.g., along the z-axis. This allows the focus position of the laser beam to be adjusted. This adjustability enables variation of the welding height or the weld seam height, which may be necessary due to the surface properties of the workpieces. The control device 60 can be configured to adjust the position of the collimation optics 12 based on the first observation signal.
[0098] Figure 4 shows a laser processing head 1 according to a further aspect of the disclosure. The laser processing head 1 of Figure 4 is based on the laser processing head of Figure 1 and additionally comprises a second observation device 80, which can be configured as a coaxial observation device.
[0099] In Fig. 4, the paths of the laser beam and the observation beam path of the second observation device 80 have been omitted for the sake of clarity.
[0100] The second observation device 80 can have an observation beam path that is coaxial with the beam axis of the laser beam and strikes or is reflected back from the workpieces at the processing position 90. The laser processing head 1 can include a coupling optic (not shown) for coupling the observation beam path of the second camera 80 into the beam path of the laser beam. The coupling optic can, for example, be a beam splitter and / or include a dichroic mirror. The laser processing head 1 can further include a deflection device (not shown) by means of which the laser beam can be deflected onto the coupling optic.
[0101] The optical axis of the coupling optics can be aligned parallel to the optical axis of the focusing optics 20. The second observation device 80 can be aligned such that its observation beam path is directed centrally onto the focusing optics 20.
[0102] The field of view of the second observation device 80 can include the TCP. A second observation signal, generated by the second observation device 80, can contain information about the TCP or the processing position. The second observation device 80 or the second observation signal can be used to align or fine-tune the position of the feed device 30 or the welding feeder. - Precitec GmbH & Co. KG, Case: PR 986 WO
[0103] Set data relating to the TCP are used. The control device 60 can be configured to receive the second observation signal and, based on this, adjust the orientation of the feed device 30.
[0104] The laser processing head 1 in the example of Fig. 4 can also include the collimation optics 12, as described with reference to Fig. 3.
[0105] Figure 5 shows a laser processing head 1 according to a further aspect of the disclosure. The laser processing head 1 of Figure 5 is based on the laser processing head of Figure 4. Alternatively or additionally to the second observation device 80, which can be configured as a coaxial observation device, the laser processing head 1 according to the example in Figure 5 comprises a scanner device 14.
[0106] The scanner device 14 can be a galvanometer scanner device with at least one deflectable scan element (e.g., a scan mirror), and in particular with two deflectable scan elements. Angular settings of the at least one scan element can also be referred to as scanner settings. The scanner device 14 can be configured to deflect the laser beam in one direction or in two different directions (i.e., forming an angle other than 0° and 180° with each other). The scanner device 14 can be configured to deflect the laser beam within a predefined scan field. A scan field is defined as an area into which the laser beam can be directed by means of the scanner device 14.
[0107] The scanner device 14 can further be configured to generate a wobble motion of the laser beam and / or to vary the position of the laser beam according to an illumination pattern. The wobble motion can, for example, include a sinusoidal component whose deflection can be adjusted by a (scan) amplitude, a (scan) frequency, and / or an offset transverse to the processing direction. The control device 60 can be configured to control the scanner device 14 based on the first observation signal. The wobble motion, in particular its amplitude, can, for example, be adapted to the geometry of the joint. With a wider gap between the workpieces, a wobble motion with a larger amplitude can improve the welding result, while with a smaller gap, a wobble motion with a smaller amplitude may be sufficient for a sufficiently good weld.
[0108] The laser processing head 1 in the example of Fig. 5 can also include the collimation optics 12, as described with reference to Fig. 3. Precitec GmbH & Co. KG, Case: PR 986 WO
[0109] The laser processing head 1 can include an adjustment device 35. The adjustment device 35 can be configured to adjust the feed device 30 in at least one direction x, y, z. The control device 60 can be configured to control the adjustment device 35 based on the deflection of the laser beam by the scanner device 14, or to adjust the feed device 30. Additionally or alternatively, the control device 60 can be configured to control the adjustment device 35 based on the first observation signal, or to adjust the feed device 30.
[0110] Figure 6 shows a laser processing head 1 according to a further aspect of the disclosure. The laser processing head 1 of Figure 6 is based on the laser processing head of Figure 4. The laser processing head 1 in the example of Figure 6 can include a third observation device 70, the observation beam path of which, spaced apart from the beam path of the laser beam, strikes an area 92 in the processing direction behind the laser processing head 1. In other words, the field of view of the third observation device 70 can be arranged in the trailing position.
[0111] The third observation device 70 can be arranged outside the laser processing head 1 on the laser processing head 1. The third observation device 70 can be configured to determine a distance to the weld seam after the processing position 90, based on triangulation. The third observation device 70 can acquire and provide a third observation signal. The control device 60 can be configured to check the weld seam or the welding result based on the third observation signal, for example, with regard to defects and / or pores in the weld seam. For this purpose, the control device 60 can process and / or evaluate the third observation signal using a trained neural network.
[0112] The control device 60 can include a storage device 61 in which instructions for executing the trained neural network are stored. Furthermore, reference data of previously known defects in welds can be stored in the storage device. The control device 60 can be configured to evaluate the third observation signal by comparison with the reference data for monitoring the weld or for quality assessment. Precitec GmbH & Co. KG, Case: PR 986 WO
[0113] The laser processing head 1 in the example of Fig. 6 can further comprise the collimation optics 12, as described with reference to Fig. 3, the second observation device 80, as described with reference to Fig. 4 and / or the scanner device 14, as described with reference to Fig. 5.
[0114] Figure 7 shows a system for welding two workpieces together using a laser beam according to one aspect of the disclosure.
[0115] System 100 can include a laser processing head 1. In the example of Fig. 7, a laser processing head 1 according to the example of Fig. 6 is shown, but it is not limited to this and can also be a laser processing head according to any of the examples shown in Figures 1-5. System 100 can further include a laser source 50 which is coupled to the laser processing head 1, more precisely to its input port 10. System 100 can also include a linear drive axis 110 for weld seam tracking. The linear drive axis 110 can move the entire laser processing head relative to the workpieces. Alternatively, a linear drive axis can be provided which can move the workpieces relative to the laser processing head 1. The linear drive axis 110 is thus configured to generate a relative movement between the laser processing head 1 and the workpieces, preferably in the x / y plane.
[0116] The control device 60 can be configured to control and / or regulate the welding process based on the first observation signal, the second observation signal, and / or the third observation signal. The control device can control and / or regulate the feed device 30, the laser power of the laser source 50, and / or a process via the linear drive axis 110.
[0117] Figure 8 shows a flowchart of a method for welding two workpieces using a laser beam according to one aspect of the disclosure.
[0118] The sequence of process steps refers to each processing position. The sequence of process steps can be repeated, at least partially, for each processing position. The order of process steps S20, S30, and S40 is arbitrary. In particular, process step S20 can be executed continuously, with its execution being adjusted by process step S40. The same applies to process step S30. Precitec GmbH & Co. KG, Case: PR 986 WO
[0119] In a first process step S10, a first observation signal from an area 91 in the processing direction in front of the laser beam can be detected by a first observation device 40.
[0120] In a second process step S20, the laser beam can be directed to weld the workpieces 94, 95. Optionally, the focus position of the laser beam can be adjusted in the z-direction. Furthermore, the laser beam can optionally be deformed and / or deflected using the scanner device 14. The power of the laser beam can also be adjusted.
[0121] In a third process step S30, a welding filler material for welding the workpieces 94, 95 can be fed by a feeding device 30 without contact with the workpieces and / or the joint. The welding filler material can, in particular, be a wire which may comprise, for example, aluminum, copper, steel and / or stainless steel.
[0122] In a fourth process step, S40, the welding can be controlled and / or regulated. In particular, the laser beam input and / or the supply of the welding filler material can be controlled and / or regulated based on the first observation signal. Furthermore, the laser beam input and / or the supply of the welding filler material can be controlled and / or regulated based on the second and / or third observation signal.
[0123] Regulating and / or controlling the laser beam's direction can include changing the position of the collimation optics 12, adjusting the scanner device 14, adjusting the scan amplitude, adjusting the laser power and / or adjusting a relative position between the laser processing head 1 and the workpieces or the joint.
[0124] Regulating and / or controlling the supply of welding consumables, especially wire, may include changing the supply speed, changing the supply position and / or changing the supply height above the workpieces or above the joint.
[0125] Based on the initial observation signal, the welding process can be adaptively adjusted to the parameters imposed by the workpieces to ensure a reliable weld. An instantaneous post-analysis by Precitec GmbH & Co. KG, Case: PR 986 WO
[0126] The welding seam using the third observation device and the diverse adjustment options of the laser processing head 1 for shaping and / or deflecting the laser beam enable versatile applications of the laser processing head 1 with consistently high weld seam quality.
[0127] Reference symbol list
[0128] 1 laser processing head
[0129] 10 Entry sports
[0130] 12 Collimation optics
[0131] 14 Scanner device
[0132] 20 Focusing optics
[0133] 30 Feed device
[0134] 35 Adjustment device
[0135] 40 first observation device
[0136] 50 Laser source
[0137] 60 Control device
[0138] 61 Storage device of the control device
[0139] 70 third observation device
[0140] 80 second observation device
[0141] 90 processing position
[0142] 91 Area in the processing direction in front of the laser beam (forward)
[0143] 92 Area in the processing direction after the laser beam (follow-up)
[0144] 93 Joint
[0145] 94, 95 workpieces
[0146] 100 System
[0147] 110 linear drive axis
[0148] S10 Procedure step "Capturing a first observation signal"
[0149] S20 Process step "Injection of the laser beam"
[0150] S30 Process step "Non-contact supply of welding filler material"
[0151] S40 Process step "Control and / or regulate welding"
Claims
Precitec GmbH & Co. KG, Case: PR 986 WO Patent claims 1. Laser processing head (1) for welding two workpieces (94, 95) using a laser beam, the laser processing head (1) comprising: an entry port (10) for coupling the laser beam into the laser processing head (1), a focusing optic (20) for directing the laser beam onto the workpieces (94, 95), a feed device (30) for the contactless feeding of a welding filler material, wherein the feed device (30) is arranged at a distance from a beam axis of the laser beam, a first observation device (40) which is arranged at a distance from the beam axis of the laser beam and is configured to detect a first observation signal from an area (91) in the processing direction in front of the laser beam, and a control device (60) which is configured to control and / or regulate the welding based on the first observation signal.
2. Laser processing head (1) according to claim 1, wherein the control device (60) is configured to set at least one of the following process parameters based on the first observation signal: a laser power a feed rate of the welding filler material, a focus position of the laser beam, a position of the laser beam on the workpieces (94, 95), an irradiation pattern of the laser beam, a position of the feed device (30) along at least one direction, in particular a z-direction parallel to the optical axis of the focusing optics (20), and / or a relative velocity between the workpieces (94, 95) and the laser processing head.
3. Laser processing head (1) according to one of the preceding claims, wherein the first observation device (40) and / or the control device (60) is configured to determine a distance to the two workpieces (94, 95) to be joined based on triangulation.
4. Laser processing head (1) according to one of the preceding claims, wherein the first observation signal provides information about the geometry of a joint. Precitec GmbH & Co. KG, Case: PR 986 WO (93) between the two workpieces (94, 95) and / or contains information about the surface condition of at least one of the two workpieces (94, 95) and / or the joint (93).
5. Laser processing head (1) according to one of the preceding claims, wherein the first observation device (40) is arranged outside the laser processing head (1) on the laser processing head (1) and / or wherein an optical axis of the first observation device (40) forms an angle (a) with the beam axis of the laser beam.
6. Laser processing head (1) according to one of the preceding claims, further comprising a scanner device (14) which is configured to deflect the laser beam along at least one direction, wherein the control device (60) is further configured to control a deflection of the laser beam by the scanner device (14).
7. Laser processing head (1) according to one of the preceding claims, further comprising an adjustment device (35) for adjusting the feed device (30) along at least one direction, preferably the z-direction.
8. Laser processing head (1) according to claim 7, wherein the adjusting device (35) is configured to adjust the feed device (30) in the z-direction and at least one direction perpendicular to the z-direction.
9. Laser processing head (1) according to claim 7 or 8, if dependent on claim 6, wherein the control device (60) is configured to control the adjustment device (35) based on the deflection of the laser beam by the scanner device (14).
10. Laser processing head (1) according to one of the preceding claims, further comprising a second observation device (80) whose observation beam path is at least partially coaxial to the beam path of the laser beam, and which is configured to determine a position for the supply of the welding filler material.
11. Laser processing head (1) according to claim 10, wherein the second observation device (80) is further configured to detect a second observation signal from a processing position (90) and / or in the run-up to the processing position (90), wherein the control device (60) is further configured to determine the quality of the processing of the workpieces (94, 95) based on the second observation signal of the second observation device (80). Precitec GmbH & Co. KG, Case: PR 986 WO to determine and / or to control the welding of the two workpieces (94, 95) based on the second observation signal.
12. Laser processing head (1) according to claim 10 or 11, wherein the second observation signal comprises grayscale image data and / or the control device (60) is configured to improve the contrast of the second observation signal by means of a neural network.
13. Laser processing head (1) according to one of the preceding claims, further comprising a collimation optic (12) for collimating the laser beam, wherein the collimation optic (12) is configured to adjust the focus position of the laser beam.
14. Laser processing head (1) according to one of the preceding claims, wherein the welding filler material is wire-shaped or powder-shaped and / or wherein the welding filler material comprises steel, stainless steel, aluminium and / or copper.
15. Laser processing head (1) according to one of the preceding claims, further comprising a third observation device (70) which is arranged spaced apart from the beam axis of the laser beam and is configured to detect a third observation signal from an area (92) in the processing direction after the laser beam, wherein the control device (60) is further configured to control the welding based on the third observation signal.
16. System (100) for welding two workpieces (94, 95) using a laser beam, the system (100) comprising: a laser source (50), a linear drive axis (110) for weld seam tracking, and a laser processing head (1) according to one of the preceding claims, wherein the laser processing head (1) is coupled to the laser source (50) and is arranged on the linear drive axis (110).
17. System (100) according to the preceding claim, wherein the control device (60) is further configured to control the linear drive axis (110) and / or a power of the laser source (50) based on the first observation signal.
18. Method for welding two workpieces (94, 95) using a laser beam, the method comprising: Directing the laser beam to weld the workpieces (94, 95); Precitec GmbH & Co. KG, Case: PR 986 WO Non-contact supply of a welding filler material for welding the workpieces (94, 95) by a supply device (30) which is arranged at a distance from a beam axis of the laser beam; Capturing a first observation signal from an area (91) in the processing direction in front of the laser beam by a first observation device (40) which is arranged at a distance from the beam axis of the laser beam; and Controlling and / or regulating the welding process, in particular the application of the laser beam and / or the supply of the welding filler material, based on the first observation signal.