Laser welding device

Abstract

The present invention provides a laser welding device, which relates to the field of laser welding technology. The laser welding device includes a visual positioning camera, a laser welding head and a laser cleaning and marking composite head. The laser cleaning and marking composite head is used to access a pulsed laser optical fiber and emit a first laser beam. The laser cleaning and marking composite head includes a beam splitting scanning optical path system. The beam splitting scanning optical path system is used to split the first laser beam into a first sub-laser beam and a second sub-laser beam. The second sub-laser beam is used to perform laser marking in a U-rib seam area. The visual positioning camera is used to collect an image signal of the U-rib seam area according to the laser marking. The laser welding head is used to adjust to a specified position according to the image signal. The laser welding head is used to access a continuous laser optical fiber and emit a second laser beam. Compared with the prior art, the laser welding device of the present invention removes surface dirt and impurities, and makes the surface have a characteristic structure that is easy to identify, and has the advantages of being easy to identify and accurate in positioning.

Description

Technical Field

[0001] The present invention relates to the technical field of laser welding, and in particular to a laser welding device. Background Art

[0002] U-rib is one of the important structures of large steel bridges in my country. The welding of U-rib and bottom plate / top plate is the main work in manufacturing. Laser welding can easily achieve full penetration of thick materials and double-sided forming of single-sided welding, thus effectively solving the problem of insufficient penetration of arc welding. It is increasingly widely used in U-rib welding. In order to improve the automation level and accuracy, visual positioning is often used to obtain the position information of the joint online to complete automated welding.

[0003] During the production and storage process, the U-ribs and the bottom / top plate surfaces are very susceptible to oxidation and rust, which directly leads to metallurgical defects such as pores and slag inclusions during the subsequent welding process, affecting the service life of the bridge. Compared with traditional cleaning technologies such as mechanical grinding and pickling, laser cleaning is a non-contact, "green" and pollution-free cleaning method that can quickly and effectively remove oil stains, oxide films, etc. on the metal surface and improve defects such as pores and slag inclusions. However, the metal surface after laser cleaning is smooth and bright, with high reflectivity, which causes the collected images to be exposed and the features to be difficult to identify. This will cause deviations in subsequent visual positioning, resulting in the inability to identify the joint position or the welding position deviating from the joint position. Summary of the invention

[0004] The problem to be solved by the present invention is: how to provide a laser welding device with a cleaning mark function.

[0005] The present invention provides a laser welding device, comprising: a visual positioning camera, a laser welding head and a laser cleaning and marking composite head, wherein the laser cleaning and marking composite head is used to access a pulsed laser optical fiber and emit a first laser beam, wherein the laser cleaning and marking composite head comprises a beam splitting scanning optical path system, wherein the beam splitting scanning optical path system is used to split the first laser beam into a first sub-laser beam and a second sub-laser beam, wherein the first sub-laser beam is used to clean a metal surface in a U-rib seam area, wherein the second sub-laser beam is used to perform laser marking in the U-rib seam area, wherein the visual positioning camera is used to collect an image signal of the U-rib seam area according to the laser marking, wherein the laser welding head is used to adjust to a specified position according to the image signal, wherein the laser welding head is used to access a continuous laser optical fiber and emit a second laser beam, wherein the second laser beam is used to perform welding in the U-rib seam area.

[0006] Compared with the prior art, the laser welding device provided by the present invention has the following beneficial effects but is not limited to them:

[0007] The laser welding device described in the present invention, before the laser welding head welds the U-rib seam area, first connects the laser cleaning and marking composite head to the pulsed laser fiber and emits a first laser beam, and the beam splitting scanning optical path system of the laser cleaning and marking composite head can split the first laser beam into a first sub-laser beam and a second sub-laser beam, wherein the first sub-laser beam can clean the metal surface of the U-rib seam area, that is, remove surface dirt and impurities (oxide film, rust and oil, etc.), wherein the second sub-laser beam can perform laser marking on the cleaned base metal surface, even if the metal surface has a characteristic structure that is easy for the visual positioning camera to recognize, and then the visual positioning camera can collect the image signal of the U-rib seam area based on the above laser marking, and the laser welding head can be adjusted to the specified position according to the above image signal, and then the laser welding head is connected to the continuous laser fiber and emits the second laser beam, and the second laser beam can perform welding operations in the U-rib seam area. Compared with the prior art, the laser welding device of the present invention removes surface dirt and impurities through pre-welding cleaning and laser marking on the cleaned base metal surface, and makes the surface have a characteristic structure that is easy to identify. It can effectively suppress defects such as weld porosity, inclusions and unfusion, improve the quality of the weld, and has the advantages of being easy to identify and accurately positioning, avoiding the problems of insufficient welding or lack of welding caused by identification deviation.

[0008] Optionally, the beam splitting scanning optical path system includes a collimating lens and a beam splitter, the collimating lens is used to collimate the first laser beam into a parallel beam, and the parallel beam is used to split the first laser beam into the first sub-laser beam and the second sub-laser beam through the beam splitter.

[0009] Optionally, the beam-splitting scanning optical path system also includes a first Y-axis galvanometer, a first focusing field lens and a first protective lens, wherein the first Y-axis galvanometer is used to receive the first split laser beam and reflect it to the first focusing field lens, and the first focusing field lens is used to focus the first split laser beam and emit it after passing through the first protective lens.

[0010] Optionally, the beam splitter is arranged tilted relative to the collimating lens, and is used to reflect the first split laser beam to the first Y-axis galvanometer.

[0011] Optionally, the first Y-axis galvanometer is arranged in parallel with the beam splitter, and is used to emit the first split laser beam perpendicular to the light emitting surface of the laser cleaning and marking composite head.

[0012] Optionally, the beam-splitting scanning optical path system also includes a second Y-axis galvanometer, an X-axis galvanometer, a second focusing field lens and a second protective lens, the second Y-axis galvanometer is used to receive the second split laser beam and reflect it to the X-axis galvanometer, the X-axis galvanometer is used to reflect the second split laser beam to the second focusing field lens, and the second focusing field lens is used to focus the second split laser beam and emit it after passing through the second protective lens.

[0013] Optionally, the second Y-axis galvanometer and the beam splitter are respectively tilted relative to the collimating lens, and the second Y-axis galvanometer and the beam splitter have opposite inclination angles, and are used to reflect the second split laser beam to the X-axis galvanometer.

[0014] Optionally, the X-axis galvanometer is arranged in parallel with the second Y-axis galvanometer, and is used to emit the second sub-laser beam perpendicular to the light emitting surface of the laser cleaning and marking composite head.

[0015] Optionally, the laser marker is a micro-nano structure groove distributed in parallel in the U-rib seam area, and the micro-nano structure groove is used as a visual recognition feature point of the visual positioning camera.

[0016] Optionally, the laser welding device further comprises a positioning bracket, and the visual positioning camera, the laser welding head and the laser cleaning and marking composite head are arranged on the positioning bracket at intervals along the same axis, and the visual positioning camera is located between the laser welding head and the laser cleaning and marking composite head. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The structure of the laser welding device according to the embodiment of the present invention is shown in FIG. Figure 1 ;

[0018] Figure 2 Schematic diagram of the structure of the beam splitting scanning optical path system according to an embodiment of the present invention.

[0019] Description of reference numerals:

[0020] 1. Bottom plate / top plate; 2. U-rib joint area; 3. U-rib; 4. Second laser beam; 5. Laser welding head; 6. Visual positioning camera; 7. Laser cleaning and marking composite head; 8. Beam splitting scanning optical path system; 9. First sub-laser beam; 10. Second sub-laser beam; 11. Second protective lens; 12. Second focusing field lens; 13. X-axis galvanometer; 14. Beam splitter; 15. First laser beam; 16. Collimating lens; 17. First Y-axis galvanometer; 18. Second Y-axis galvanometer; 19. First focusing field lens; 20. First protective lens. DETAILED DESCRIPTION

[0021] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0022] In the description of the present invention, the directions or positional relationships indicated by “up”, “down”, “left”, “right”, “top”, “bottom”, “front”, “back”, “inside” and “outside” are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present disclosure. They do not indicate or imply that the device referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they should not be understood as limiting the scope of protection of the present disclosure.

[0023] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0024] In the description of this specification, the description with reference to the terms "embodiment", "one embodiment" and "one implementation" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or implementation are included in at least one embodiment or implementation of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or implementation. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or implementations in a suitable manner.

[0025] Moreover, the X-axis in the accompanying drawings represents the horizontal direction, that is, the left and right position, and the positive direction of the X-axis (that is, the direction of the arrow of the X-axis) represents the left, and the negative direction of the X-axis (that is, the direction opposite to the positive direction of the X-axis) represents the right; the Y-axis in the accompanying drawings represents the longitudinal direction, that is, the front and back position, and the positive direction of the Y-axis (that is, the direction of the arrow of the Y-axis) represents the front, and the negative direction of the Y-axis (that is, the direction opposite to the positive direction of the Y-axis) represents the back.

[0026] It should also be noted that the aforementioned X-axis and Y-axis are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as a limitation of the present invention.

[0027] like Figures 1 to 2As shown, the laser welding device of the embodiment of the present invention includes: a visual positioning camera 6, a laser welding head 5 and a laser cleaning and marking composite head 7, the laser cleaning and marking composite head 7 is used to access the pulsed laser fiber and emit a first laser beam 15, the laser cleaning and marking composite head 7 includes a beam splitting scanning optical path system 8, the beam splitting scanning optical path system 8 is used to split the first laser beam 15 into a first sub-laser beam 9 and a second sub-laser beam 10, the first sub-laser beam 9 is used to clean the metal surface of the U-rib seam area 2, the second sub-laser beam 10 is used to perform laser marking in the U-rib seam area 2, the visual positioning camera 6 is used to collect the image signal of the U-rib seam area 2 according to the laser marking, the laser welding head 5 is used to adjust to the specified position according to the image signal, the laser welding head 5 is used to access the continuous laser fiber and emit the second laser beam 4, the second laser beam 4 is used to weld in the U-rib seam area 2.

[0028] In this embodiment, before the laser welding head 5 welds the U-rib seam area, the laser cleaning mark composite head 7 is first connected to the pulsed laser fiber and emits a first laser beam. The beam splitting scanning optical path system 8 of the laser cleaning mark composite head 7 can split the first laser beam 15 into a first sub-laser beam 9 and a second sub-laser beam 10, wherein the first sub-laser beam 9 can be used to weld the U-rib seam area 2 (attached Figure 1 The metal surface of the bottom plate / top plate 1 and the U rib 3 intersection area) is cleaned, that is, the surface dirt and impurities (oxide film, rust and oil, etc.) are removed, wherein the second sub-laser beam 10 can be laser marked on the cleaned base metal surface, even if the metal surface has a characteristic structure that is easy for the visual positioning camera 6 to identify, and then the visual positioning camera 6 can collect the image signal of the U rib joint area 2 based on the above laser marking, and the laser welding head 5 can be adjusted to a specified position according to the above image signal, and then the laser welding head 5 is connected to the continuous laser fiber and emits the second laser beam 4, and the second laser beam 4 can perform welding operations in the U rib joint area 2. Compared with the prior art, the laser welding device of the present invention removes surface dirt and impurities through pre-welding cleaning and laser marking on the cleaned base metal surface, and makes the surface have a characteristic structure that is easy to identify, which can effectively suppress defects such as weld porosity, inclusions and unfused, improve the quality of the weld, and has the advantages of being easy to identify and accurately positioned, avoiding the problems of insufficient welding and lack of welding caused by identification deviation.

[0029] In the above working process, by designing the beam scanning optical path system 8, the laser cleaning function and the laser marking function are concentrated in the laser cleaning and marking composite head 7, and only one laser generator is used to realize the above two functions, which greatly controls the cost, and the structure is compact and easy to install and control. By integrating the visual positioning camera 6, the laser welding head 5 and the laser cleaning and marking composite head 7, cleaning, marking, visual recognition and welding can be carried out online at the same time, and welding can be completed in one stroke, thereby improving welding efficiency.

[0030] Optionally, the beam splitting scanning optical path system 8 includes a collimating lens 16 and a beam splitter 14 , the collimating lens 16 is used to collimate the first laser beam 15 into a parallel beam, and the parallel beam is used to split the first laser beam 15 into a first sub-laser beam 9 and a second sub-laser beam 10 through the beam splitter 14 .

[0031] In this embodiment, combined with the attached Figure 1 and attached Figure 2 As shown, the laser cleaning mark composite head 7 can be connected to a pulsed laser fiber, such as a pulsed laser, and the indication light of the pulsed laser is positioned to the surface to be processed. The pulsed laser receives the control signal and emits light, that is, emits a first laser beam 15, wherein the pulsed laser includes but is not limited to any one of a nanosecond laser, a picosecond laser and a femtosecond laser. The first laser beam 15 is first collimated into a parallel beam by a collimating lens 16 of a beam splitting scanning optical path system 8, and the parallel beam is split into a first sub-laser beam 9 and a second sub-laser beam 10 by a beam splitter 14. The laser cleaning mark composite head 7 can be connected to a 1064nm nanosecond pulsed laser, the beam splitter 3 can be a 70 / 30 beam splitter, and the deflection angle can be 45°.

[0032] Optionally, the beam-splitting scanning optical path system 8 also includes a first Y-axis galvanometer 17, a first focusing field lens 19 and a first protective lens 20. The first Y-axis galvanometer 17 is used to receive the first split laser beam 9 and reflect it to the first focusing field lens 19. The first focusing field lens 19 is used to focus the first split laser beam 9 and emit it after passing through the first protective lens 20.

[0033] In this embodiment, combined with the attached Figure 2 As shown, the first split laser beam 9 after being split by the beam splitter 14 is reflected to the first Y-axis galvanometer 17. The pulse laser scans forward through the rotation of the first Y-axis galvanometer 17, and is focused by the first focusing field lens 19 and irradiated to the surface of the substrate after passing through the first protective lens 20, so that the dirt is burned and fully vaporized and decomposed to achieve a cleaning effect. The first protective lens 20 not only does not weaken the laser output energy, but also protects the first focusing field lens 19, blocks or prevents high-temperature splashes from splashing onto the first focusing field lens 19. The processing accuracy requirements can be guaranteed by regularly replacing the first protective lens 20. The scanning angle of the first Y-axis galvanometer 17 can be ±2°, and the scanning range can be 0-20mm.

[0034] Optionally, the beam splitter 14 is tilted relative to the collimating lens 16 and is used to reflect the first split laser beam 9 to the first Y-axis galvanometer 17 .

[0035] In this embodiment, combined with the attached Figure 2 As shown, the deflection angle of the beam splitter 14 may be 45°, and the beam splitter 14 may reflect 30% of the pulsed laser to the first Y-axis galvanometer 17 for laser cleaning.

[0036] Optionally, the first Y-axis galvanometer 17 is arranged in parallel with the beam splitter 14 and is used to emit the first split laser beam 9 perpendicularly to the light emitting surface of the laser cleaning and marking composite head 7 .

[0037] In this embodiment, combined with the attached Figures 1 to 2 As shown, the first Y-axis galvanometer 17 is arranged in parallel with the beam splitter 14, and the deflection angle can be 45°, so that the first split laser beam 9 can be emitted perpendicular to the U-rib seam area 2 (see FIG. Figure 1 or attached Figure 2 The scanning angle and the scanning straight line range are selected according to the use requirements.

[0038] Optionally, the beam-splitting scanning optical path system 8 also includes a second Y-axis galvanometer 18, an X-axis galvanometer 13, a second focusing field lens 12 and a second protective lens 11. The second Y-axis galvanometer 18 is used to receive the second split laser beam 10 and reflect it to the X-axis galvanometer 13. The X-axis galvanometer 13 is used to reflect the second split laser beam 10 to the second focusing field lens 12. The second focusing field lens 12 is used to focus the second split laser beam 10 and emit it after passing through the second protective lens 11.

[0039] In this embodiment, combined with the attached Figure 2 As shown, the beam splitter 14 can reflect 70% of the pulsed laser to the second Y-axis galvanometer 18, which is then reflected twice by the X-axis galvanometer 13, focused by the second focusing field lens 12, and irradiated to the surface of the substrate after passing through the second protective lens 11, wherein the scanning speed of the second Y-axis galvanometer 18 is more than ten times the scanning speed of the first Y-axis galvanometer 17, and in conjunction with the X-axis galvanometer 13, laser etching is performed to obtain a laser mark that is easy for the visual positioning camera 6 to identify, so that the subsequent visual positioning camera 6 can visually identify the joint position more accurately, and prevent the phenomenon of being unable to identify or identifying too large a deviation. The second protective lens 11 will not only not weaken the laser output energy, but also protect the second Y-axis galvanometer 18, block or prevent high-temperature splashes from splashing onto the second Y-axis galvanometer 18, and the processing accuracy requirements can be guaranteed by regularly replacing the second protective lens 11. The scanning angle between the second Y-axis galvanometer 18 and the X-axis galvanometer 13 can be ±2°, and the scanning range can be 0-20mm.

[0040] Optionally, the second Y-axis galvanometer 18 and the beam splitter 14 are respectively tilted relative to the collimating lens 16 , and the second Y-axis galvanometer 18 and the beam splitter 14 have opposite tilt angles, and are used to reflect the second split laser beam 10 to the X-axis galvanometer 13 .

[0041] In this embodiment, combined with the attached Figure 2 As shown, the second Y-axis galvanometer 18 and the beam splitter 14 are respectively arranged tilted relative to the collimating lens 16, wherein the second Y-axis galvanometer 18 can be arranged directly below the beam splitter 14 (see FIG. Figure 2 The deflection angle is opposite to that of the beam splitter 14, so that the second split laser beam 10 can be reflected onto the X-axis galvanometer 13.

[0042] Optionally, the X-axis galvanometer 13 is arranged in parallel with the second Y-axis galvanometer 18 , and is used to emit the second sub-laser beam 10 perpendicularly to the light emitting surface of the laser cleaning and marking composite head 7 .

[0043] In this embodiment, combined with the attached Figures 1 to 2 As shown, the second Y-axis galvanometer 18 is arranged in parallel with the X-axis galvanometer 13, so that the second laser beam 10 can be emitted perpendicularly to the U-rib seam area 2 (see FIG. Figure 1 or attached Figure 2 The scanning angle and the scanning straight line range are selected according to the use requirements.

[0044] Optionally, the laser mark is a micro-nano structure groove distributed in parallel in the U-rib seam area 2 , and the micro-nano structure groove is used as a visual recognition feature point of the visual positioning camera 6 .

[0045] In this embodiment, the second sub-laser beam 10 can laser etch the U-rib seam area 2 to obtain parallel distributed micro-nano structure grooves. The above-mentioned micro-nano structure grooves can be used as feature points for visual recognition of the visual positioning camera 6, so that the subsequent visual positioning camera 6 can visually recognize the seam position more accurately and prevent the phenomenon of being unable to recognize or having excessive recognition deviation.

[0046] Optionally, the laser welding device also includes a positioning bracket, and the visual positioning camera 6, the laser welding head 5 and the laser cleaning and marking composite head 7 are arranged on the positioning bracket at intervals along the same axis, and the visual positioning camera 6 is located between the laser welding head 5 and the laser cleaning and marking composite head 7.

[0047] In this embodiment, the visual positioning camera 6, the laser welding head 5 and the laser cleaning and marking composite head 7 can be installed on the positioning bracket at intervals along the same axis, and the visual positioning camera 6 is located between the laser welding head 5 and the laser cleaning and marking composite head 7. The positioning bracket can drive the three to move in the welding direction (attached Figure 1 The X-axis moves in the opposite direction), laser cleaning mark / laser welding is carried out simultaneously, and the visual positioning camera 6, the laser welding head 5 and the laser cleaning mark composite head 7 move to the right (attached Figure 1 The X-axis moves in the opposite direction) at a welding speed of v, and the distance between the second laser beam 4 and the first sub-laser beam 9 is x. After a time t (t=x / v), the continuous laser fiber (continuous fiber laser) connected to the laser welding head 5 receives the control signal and emits light, and the welding is completed according to the joint position visually located by the visual positioning camera 6.

[0048] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features.

[0049] Although the disclosure is disclosed as above, the protection scope of the disclosure is not limited thereto. Those skilled in the art may make various changes and modifications without departing from the spirit and scope of the disclosure, and these changes and modifications will fall within the protection scope of the present invention.

Claims

1. A laser welding device, characterized in that: include: A visual positioning camera (6), a laser welding head (5) and a laser cleaning and marking composite head (7), wherein the laser cleaning and marking composite head (7) is used to access a pulsed laser optical fiber and emit a first laser beam (15), wherein the laser cleaning and marking composite head (7) comprises a beam splitting scanning optical path system (8), wherein the beam splitting scanning optical path system (8) is used to split the first laser beam (15) into a first sub-laser beam (9) and a second sub-laser beam (10), wherein the first sub-laser beam (9) is used to clean a metal surface in a U-rib joint area (2), and the second sub-laser beam (10) is used to clean a metal surface in a U-rib joint area (2). The rib seam area (2) is laser marked, the visual positioning camera (6) is used to collect image signals of the U-rib seam area (2) according to the laser mark, the laser welding head (5) is used to adjust to a specified position according to the image signal, the laser welding head (5) is used to access a continuous laser optical fiber and emit a second laser beam (4), the second laser beam (4) is used to perform welding in the U-rib seam area (2); the beam splitting scanning optical path system (8) includes a collimating lens (16) and a beam splitter (14), the collimating lens (16) is used to collimate the first laser beam ( 15) is collimated into a parallel light beam, and the parallel light beam is used to split the first laser beam (15) into the first sub-laser beam (9) and the second sub-laser beam (10) through the beam splitter (14); the beam splitting scanning optical path system (8) also includes a first Y-axis galvanometer (17), a first focusing field lens (19) and a first protective lens (20), the first Y-axis galvanometer (17) is used to receive the first sub-laser beam (9) and reflect it to the first focusing field lens (19), and the first focusing field lens (19) is used to focus the first sub-laser beam (9) and pass through the first protective lens The second laser beam (10) is emitted after passing through a lens (20); the beam splitting scanning optical path system (8) further comprises a second Y-axis galvanometer (18), an X-axis galvanometer (13), a second focusing field lens (12) and a second protective lens (11); the second Y-axis galvanometer (18) is used to receive the second laser beam (10) and reflect it to the X-axis galvanometer (13); the X-axis galvanometer (13) is used to reflect the second laser beam (10) to the second focusing field lens (12); the second focusing field lens (12) is used to focus the second laser beam (10) and emit it after passing through the second protective lens (11).

2. The laser welding device according to claim 1, characterized in that: The beam splitter (14) is arranged tilted relative to the collimating lens (16), and is used to reflect the first split laser beam (9) to the first Y-axis galvanometer (17).

3. The laser welding device according to claim 1, characterized in that: The first Y-axis galvanometer (17) is arranged in parallel with the beam splitter (14), and is used to emit the first split laser beam (9) perpendicularly to the light emitting surface of the laser cleaning and marking composite head (7).

4. The laser welding device according to claim 1, characterized in that: The second Y-axis galvanometer (18) and the beam splitter (14) are respectively arranged to be tilted relative to the collimating lens (16), and the second Y-axis galvanometer (18) and the beam splitter (14) have opposite tilt angles, and are used to reflect the second split laser beam (10) to the X-axis galvanometer (13).

5. The laser welding device according to claim 1, characterized in that: The X-axis galvanometer (13) is arranged in parallel with the second Y-axis galvanometer (18), and is used to emit the second sub-laser beam (10) perpendicularly to the light emitting surface of the laser cleaning and marking composite head (7).

6. The laser welding device according to claim 1, characterized in that: The laser marking is a micro-nano structure groove distributed in parallel in the U-rib seam area (2), and the micro-nano structure groove is used as a visual recognition feature point of the visual positioning camera (6).

7. The laser welding device according to any one of claims 1 to 6, characterized in that: It also comprises a positioning bracket, wherein the visual positioning camera (6), the laser welding head (5) and the laser cleaning and marking composite head (7) are arranged on the positioning bracket at intervals along the same axis, and the visual positioning camera (6) is located between the laser welding head (5) and the laser cleaning and marking composite head (7).

Images