Image acquisition light path structure for laser welding and laser welding device

Abstract

The invention discloses a laser welding image acquisition light path structure and a laser welding device, and the laser welding image acquisition light path structure comprises a laser galvanometer module which at least comprises a light splitting light path and is used for emitting processing laser to perform spot welding operation on a to-be-processed workpiece; the coaxial camera is connected with the laser galvanometer module through a light splitting optical path and used for receiving and amplifying a welding spot image reflected after spot welding is completed. The laser galvanometer module and the coaxial camera are arranged and connected through the light splitting optical path, the laser optical path of the laser galvanometer module and the welding spot image optical path after spot welding are transmitted through the same light splitting optical path, and corresponding laser and light image transmission is achieved; and the image shot by the coaxial camera is completely consistent with the laser welding position without visual angle deviation, so that the accuracy of visual detection is ensured.

Description

Technical Field

[0001] This invention belongs to the field of panel welding technology, specifically, it relates to an image acquisition optical path structure and a laser welding device for laser welding. Background Technology

[0002] In antenna panel manufacturing, a crucial step involves laying solder sheets made of special materials onto the antenna panel grooves and then spot welding them in place. However, due to the complex shapes, varying thicknesses, and diverse types of antenna panels, this solder sheet laying and spot welding process is currently largely done manually with handheld welding torches and visual inspection, resulting in low production efficiency and inconsistent weld quality. While related machinery has emerged, and semi-automated equipment and preliminary automation technologies can alleviate some of the problems, significant limitations remain in areas such as adaptability to complex structures, multi-parameter collaborative control, and real-time visual feedback.

[0003] Specifically, laser rangefinder vision technology is widely used for image acquisition of welding points. This technology employs an independent imaging system, with the camera and lens mounted at an angle to one side of the laser head. The imaging optical axis forms a certain angle with the main laser welding optical axis and does not coincide with it, nor do they share optical components. It acquires images of the welding points through external illumination and establishes a mapping relationship between image coordinates and laser coordinates based on pre-calibration, enabling the location and quality inspection of the welding points. It features simple structure, low cost, and convenient installation, but suffers from problems such as viewing angle differences, calibration errors, and relatively low positioning accuracy.

[0004] In view of this, the present invention is proposed. Summary of the Invention

[0005] This invention provides an image acquisition optical path structure and a laser welding device for laser welding. By setting up a laser galvanometer module and a coaxial camera, the two are connected by a beam splitter. The laser optical path of the laser galvanometer module and the optical path of the weld point image after spot welding are transmitted through the same beam splitter, realizing the corresponding laser and light image transmission. Thus, the image captured by the coaxial camera is completely consistent with the laser welding position, with no viewing angle deviation, ensuring the accuracy of visual inspection.

[0006] To solve the above-mentioned technical problems, the basic concept of the technical solution adopted by the present invention is as follows: An image acquisition optical path structure for laser welding, comprising, A laser galvanometer module, including at least a beam splitter, is used to emit a processing laser to perform spot welding on the workpiece. A coaxial camera, connected to a laser galvanometer module via a beam splitter, is used to receive and amplify the reflected images of the weld points after spot welding is completed.

[0007] Furthermore, the optical path for beam splitting includes, The optical path chamber is horizontally arranged, and along the horizontal direction of the optical path chamber are a galvanometer reflecting mirror, a semi-transparent and semi-reflective mirror, and a plane mirror, which are parallel to each other and tilted at 45°. The reflective surface of the semi-transparent mirror is used to reflect the processing laser and then reflect it onto the workpiece after passing through the galvanometer mirror. The transmission surface of the semi-transparent mirror is used to project the laser reflected after spot welding and then reflect it onto the coaxial camera after passing through the plane mirror.

[0008] Furthermore, an upward-opening inlet is provided in the middle of the optical path chamber, and a first outlet and a second outlet with opposite openings are provided at both ends of the optical path chamber, with the first outlet opening downwards. The reflecting surface of the galvanometer mirror is positioned directly opposite the first exit port; the reflecting surface of the semi-transparent mirror is positioned directly opposite the entrance port; and the reflecting surface of the plane mirror is positioned directly opposite the second exit port.

[0009] Furthermore, a focusing field lens is provided at the first outlet to focus the laser reflected by the galvanometer mirror onto the welding point of the workpiece to be processed.

[0010] A laser welding apparatus, comprising the image acquisition optical path structure for laser welding as described above, and further comprising, A frame on which a reference platform is provided, and a fixture for fixing the workpiece to be processed is provided on the reference platform; A three-dimensional motion module is mounted on a frame, and a laser galvanometer module and / or a coaxial camera are fixed on the three-dimensional motion module.

[0011] Furthermore, it also includes, A global camera, mounted on the frame and / or laser galvanometer module, is used to acquire a global image of the workpiece to be processed in order to identify welding points.

[0012] Furthermore, a laser rangefinder is installed on one side of the focusing field lens, with its measuring surface at the same level as the lens of the focusing field lens, for real-time distance measurement of the welding area of ​​the workpiece to be processed.

[0013] Furthermore, it also includes a fume extraction device, located at the bottom of the laser galvanometer module, used to absorb the fumes generated during welding; The exhaust port of the smoke extraction device is connected to the purifier via a flexible hose.

[0014] By adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art: 1. This invention sets up a laser galvanometer module and a coaxial camera, which are connected by a beam splitter. The laser beam path of the laser galvanometer module and the beam path of the weld point image after spot welding are transmitted through the same beam splitter, realizing the corresponding laser and light image transmission. Therefore, the image captured by the coaxial camera is completely consistent with the laser welding position, with no viewing angle deviation, ensuring the accuracy of visual inspection.

[0015] 2. This invention ensures that all reflected light rays are strictly aligned by sequentially arranging a galvanometer reflecting mirror, a semi-transparent mirror, and a plane mirror at a 45° angle parallel to each other within the optical path cavity. Regardless of the galvanometer reflecting mirror's deflection during scanning, the solder joint imaging optical path remains coaxial and at the same point as the laser focus, thus enabling the two optical paths to achieve time-division, coaxial, and interference-free multiplexing. Furthermore, when the parallel mirrors reflect light onto the coaxial camera, the image remains unrotated and unbiased, making solder joint positioning and quality inspection more reliable.

[0016] 3. By setting a focusing field lens at the first exit port, the present invention can ensure that the focal point is uniform and the imaging is clear throughout the entire scanning area of ​​the laser welding device. At the same time, the focusing field lens is located at the bottom of the laser optical path and directly faces the welding fume, metal spatter and plasma, which can effectively protect the galvanometer reflector and stabilize the working distance. This is the key to achieving high-precision and high-quality laser welding and coaxial vision inspection.

[0017] 4. This invention sets a global camera on one side of the laser galvanometer module, so that it can take real-time pictures of the workpiece to be processed under the control of the three-dimensional motion module as the laser galvanometer module moves. By communicating with the host computer, the global camera performs a comprehensive scan of the surface of the workpiece to be processed, and the vision algorithm in the host computer identifies the optimal welding point on the surface of the workpiece to be processed.

[0018] The specific embodiments of the present invention will now be described in further detail with reference to the accompanying drawings. Attached Figure Description

[0019] The accompanying drawings, as part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments and descriptions of the invention are used to explain the invention, but do not constitute an undue limitation of the invention. Obviously, the drawings described below are merely some embodiments, and those skilled in the art can obtain other drawings based on these drawings without creative effort. In the drawings: Figure 1 This is a schematic diagram of the overall assembly structure of the laser welding device in an embodiment of the present invention; Figure 2 This is a schematic diagram of the internal structure of the machine body in an embodiment of the present invention; Figure 3This is a schematic diagram of the structure of the three-dimensional motion module in an embodiment of the present invention; Figure 4 This is a schematic diagram of the left-view structure of the laser galvanometer module and the coaxial camera in an embodiment of the present invention; Figure 5 This is a schematic diagram of the right-view structure of the laser galvanometer module and the coaxial camera in an embodiment of the present invention; Figure 6 This is a schematic diagram of the structure of the laser optical path and the solder joint image optical path in an embodiment of the present invention.

[0020] Description of main components in the diagram: 1. Frame; 2. Base platform; 3. Fixture; 4. 3D motion module; 5. Laser galvanometer module; 6. Global camera; 7. Coaxial camera; 8. Laser rangefinder sensor; 9. Smoke extraction device; 10. Frame housing; 11. Semi-transparent mirror; 12. Plane mirror; 13. Galvanometer reflecting mirror; 14. Focusing field lens; 15. Laser head.

[0021] It should be noted that these accompanying drawings and textual descriptions are not intended to limit the scope of the invention in any way, but rather to illustrate the concept of the invention to those skilled in the art by referring to specific embodiments. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below with reference to the accompanying drawings. The following embodiments are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0023] In the description of this invention, it should be noted that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0024] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0025] like Figures 1 to 6As shown, the laser welding image acquisition optical path structure of the present invention includes a laser galvanometer module 5, which includes at least a beam splitter for emitting a processing laser to perform spot welding on the workpiece to be processed. The coaxial camera 7 is connected to the laser galvanometer module 5 via a beam splitter to receive and amplify the reflected image of the weld point after spot welding is completed.

[0026] In this invention, the laser galvanometer module 5 is connected to the coaxial camera 7 via a split optical path. The laser emitted by the laser galvanometer module 5 is transmitted through the split optical path to form a laser beam for welding the workpiece. The weld image after spot welding is then transmitted to the coaxial camera 7 via the same split optical path. Thus, the laser galvanometer module 5 and the coaxial camera 7 share the same optical path, achieving corresponding laser and light image transmission. Therefore, the image captured by the coaxial camera 7 is completely consistent with the laser welding position, with no viewing angle deviation, ensuring the accuracy of visual inspection.

[0027] In addition, since the laser galvanometer module 5 and the coaxial camera 7 use the same optical axis design, there is no need for complex multi-degree-of-freedom adjustment mechanisms such as translation, rotation, and tilt to align the laser and the camera during use, which greatly shortens the debugging time. Moreover, the two share optical components and simplified mechanical structure, which greatly reduces the size of the entire welding head, making it more suitable for installation in industrial robot arms or confined spaces.

[0028] Furthermore, the optical path for beam splitting includes, The optical path chamber is horizontally arranged, and along the horizontal direction of the optical path chamber, a galvanometer reflecting mirror 13, a semi-transparent and semi-reflective mirror 11, and a plane mirror 12 are arranged in sequence. The three are parallel to each other and are inclined at 45°. The reflective surface of the semi-transparent mirror 11 is used to reflect the processing laser and then reflect it onto the workpiece after passing through the galvanometer mirror 13. The transmission surface of the semi-transparent mirror 11 is used to project the laser reflected after spot welding and then reflect it onto the coaxial camera 7 after passing through the plane mirror 12.

[0029] In this invention, the beam splitter has a horizontally arranged, closed, rigid optical cavity. A galvanometer mirror 13, a semi-transparent mirror 11, and a plane mirror 12 are sequentially integrated and installed inside this optical cavity. Specifically, the galvanometer mirror 13 and the plane mirror 12 are respectively located on the left and right sides of the optical cavity, while the semi-transparent mirror 11 is located at the center of the optical cavity. These three optical components are parallel to each other and inclined at 45° within the optical cavity, together forming a symmetrical and regular coaxial optical path.

[0030] A laser head 15 is positioned at the center of the optical path chamber. The laser head 15 is vertically positioned and emits a laser beam that is incident on a semi-transparent and semi-reflective mirror 11 that is tilted at 45° in a direction perpendicular to the main optical axis.

[0031] The specific optical path is explained as follows: The aforementioned semi-transparent mirror 11 and plane mirror 12 ensure that light rays are precisely deflected by 90° when transmitted to each of the 45° tilted mirrors. Specifically, the laser optical path is: laser head 15 (vertically downward) - semi-transparent mirror reflection (horizontally to the left) - entering galvanometer mirror 13 (vertically downward); the solder joint imaging optical path is: solder joint image (horizontally to the left and back) - semi-transparent mirror transmission (horizontally to the right) - plane mirror 12 reflection - vertically upward into the coaxial camera 7. Thus, the laser optical path and the solder joint imaging optical path share the same optical axis, and both paths share the same optical components within the same optical path cavity. Because the three optical mirrors are parallel to each other, the direction of all reflected light rays is strictly consistent. Regardless of the deflection and scanning of the galvanometer mirror 13, the solder joint imaging optical path remains coaxial and at the same point as the laser focus, enabling the two optical paths to achieve time-division, coaxial, and interference-free multiplexing. When the parallel mirror reflects the image onto the coaxial camera 7, it ensures that the image is free from rotation and bias, making the solder joint positioning and quality inspection more reliable.

[0032] Furthermore, the optical path chamber has an upward-facing inlet in the middle, and a first outlet and a second outlet with opposite openings at both ends of the optical path chamber, with the first outlet opening downwards.

[0033] Among them, the reflecting surface of the galvanometer mirror 13 is directly opposite to the first exit port; the reflecting surface of the semi-transparent mirror 11 is directly opposite to the entrance port; and the reflecting surface of the plane mirror 12 is directly opposite to the second exit port.

[0034] In this invention, the entrance and exit ports of the optical path cavity are strictly aligned with the positions of the various optical lenses inside the optical path cavity. An entrance port is located at the top center of the optical path cavity, with its center aligned with the center of the semi-transparent mirror 11. The first and second exit ports have opposite opening directions. The first exit port, serving as the laser emission point, opens downwards, and its center is aligned with the center of the galvanometer mirror 13. The second exit port, serving as the receiving point for the reflected light from the coaxial camera 7, opens upwards, and its center is aligned with the center of the plane mirror 12.

[0035] The above configuration is the core optical setup for the coaxial vision laser welding optical path, which can achieve high-reflectivity laser transmission, high-transparency imaging acquisition, and coaxial optical path without deviation, while improving optical efficiency and enhancing system stability.

[0036] Furthermore, a focusing field lens 14 is provided at the first outlet to focus the laser reflected by the galvanometer reflector 13 onto the welding point of the workpiece to be processed.

[0037] In this invention, a focusing field lens 14 is provided directly below the first emission port and above the workpiece to be processed. The focusing field lens 14 is the last optical element of the entire laser output and is also an essential functional lens for achieving stable, uniform and high-precision laser welding.

[0038] Specifically, the incident laser emitted from the laser head 15 is deflected sequentially by the semi-transparent mirror 11 and the galvanometer mirror 13 to form a parallel beam, but this is far from sufficient for welding requirements. The focusing field lens 14 utilizes the converging principle of a convex lens to precisely focus the parallel laser beam onto the workpiece surface, forming a micron-sized spot. The focused field lens 14 has highly concentrated energy, instantly melting the metal and enabling processes such as spot welding, continuous welding, and sealing welding.

[0039] Therefore, by setting the focusing field lens 14, it is possible to ensure that the focal point is uniform and the imaging is clear throughout the entire scanning area of ​​the laser welding device. At the same time, the focusing field lens 14 is located at the bottom of the laser optical path and directly faces the welding fumes, metal spatter, and plasma. It can effectively protect the galvanometer reflector 13 and stabilize the working distance, which is the key to achieving high-precision and high-quality laser welding and coaxial vision inspection.

[0040] The present invention also discloses a laser welding apparatus, comprising the image acquisition optical path structure for laser welding as described in any of the above embodiments, and further comprising, A frame 1 is provided with a reference platform 2, and a fixing fixture 3 for fixing the workpiece to be processed is provided on the reference platform 2. The three-dimensional motion module 4 is mounted on the frame 1, and the laser galvanometer module 5 and / or coaxial camera 7 are fixed on the three-dimensional motion module.

[0041] In this invention, the frame 1 has an overall frame structure and is enclosed by a sealing plate to form a closed chamber, which contains relevant electrical control components. A horizontal reference platform 2 is provided at the center of the upper end face of the frame 1, and a fixing fixture 3 is provided on the reference plane for fixing the relevant workpiece to be processed.

[0042] A three-dimensional motion module 4 is also provided on the upper surface of the frame 1, specifically including an X-axis motion module, a Y-axis motion module, and a Z-axis motion module. Each motion module can adopt an existing linear module structure, including at least linear guides and linear drive motors. The moving end of the Z-axis motion module is connected to the aforementioned laser galvanometer module 5 and coaxial camera 7. Through the relative movement of the three-dimensional motion module 4 in various directions, the positions of the laser galvanometer module 5 and the coaxial camera 7 can be accurately controlled and positioned to ensure spot welding operations on the workpiece to be processed.

[0043] Furthermore, it also includes, A global camera 6, mounted on the frame 1 and / or the laser galvanometer module 5, is used to acquire global images of the workpiece to be processed in order to identify welding points.

[0044] In this invention, a global camera 6 is installed on the frame 1 or the laser galvanometer module 5. Preferably, it is installed on one side of the laser galvanometer module 5, so that it can capture images of the workpiece to be processed in real time under the control of the three-dimensional motion module 4 as the laser galvanometer module 5 moves. A host computer is also installed on the frame 1. The laser galvanometer module 5, the three-dimensional motion module 4, and the global camera 6 are connected by communication. The global camera 6 performs a comprehensive scan of the surface of the workpiece to be processed, and the vision algorithm in the host computer identifies the optimal welding point on the surface of the workpiece. After determining the optimal welding point, the three-dimensional motion module 4 is controlled to move the laser galvanometer module 5 precisely, thereby ensuring the quality of spot welding.

[0045] In addition, the coaxial camera 7 uses a long-focal-length macro lens, which utilizes the close-up imaging principle of a convex lens to achieve high magnification. Relying on the characteristics of the long focal length, it obtains clear magnified images while ensuring a large working distance. It is perfectly matched with the coaxial optical path and can clearly image micron-level solder joints onto the camera sensor, providing a high-precision visual source for welding quality inspection and offset analysis.

[0046] Furthermore, a laser range sensor 8 is provided on one side of the focusing field lens 14, and its measuring surface is at the same level as the lens of the focusing field lens 14, which is used to measure the welding area of ​​the workpiece to be processed in real time.

[0047] In this invention, a laser rangefinder 8 is provided on the side wall of the focusing field lens 14. Its measuring surface is at the same horizontal plane as the center line of the lens of the focusing field lens 14. The laser is emitted to the welding area of ​​the workpiece to be processed for real-time distance measurement.

[0048] Because the laser rangefinder 8 and the focusing lens 14 are integrated, synchronous up, down, left, and right movements can be achieved through the control of the three-dimensional motion module 4. This allows for real-time synchronous measurement of the vertical distance between the focal point of the focusing lens 14 and the welding point of the workpiece. Specifically, the host computer communicates with the laser rangefinder 8, reading the distance value in real time and controlling the movement of the three-dimensional motion module 4 to adjust the height of the laser galvanometer module 5 in real time, thereby achieving the optimal focal length for welding and improving the strength and quality of the weld.

[0049] Furthermore, it also includes a fume extraction device 9, which is located at the bottom of the laser galvanometer module 5, for absorbing the fumes generated during welding; The exhaust port of the smoke exhaust device 9 is connected to a purifier via a flexible hose.

[0050] In this invention, a fume extraction device 9 is provided below the laser galvanometer module 5, including at least a negative pressure fume extraction mechanism. When the laser galvanometer module 5 performs spot welding on the workpiece to be processed, polluting fumes are generated. During the spot welding operation, the fume extraction device 9 is activated simultaneously to extract the generated fumes in real time, reducing the pollution of the production environment and the harm to production personnel caused by welding fumes.

[0051] More specifically, the exhaust port of the smoke exhaust device 9 is connected to a preset purifier. When the smoke exhaust device 9 extracts smoke and dust, the purifier simultaneously performs corresponding purification operations on the smoke and dust, further reducing the possibility of harmful emissions of smoke and dust.

[0052] Furthermore, a closed frame housing 10 is also provided on the frame 1. A transparent observation window is provided on the front side of the frame housing 10, which allows production personnel to observe the spot welding operation inside when the laser galvanometer module 5 is performing spot welding on the workpiece to be processed. The frame housing 10 isolates the spot welding-related components inside, effectively preventing welding fumes from damaging them.

[0053] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-described technical content to create equivalent embodiments without departing from the scope of the present invention. The implementation schemes in the above embodiments can be further combined or replaced. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. An image acquisition optical path structure for laser welding, characterized in that: include, A laser galvanometer module includes at least a beam splitter for emitting a processing laser to perform spot welding on the workpiece to be processed. A coaxial camera, connected to a laser galvanometer module via a beam splitter, is used to receive and amplify the reflected images of the weld points after spot welding is completed.

2. The image acquisition optical path structure for laser welding according to claim 1, characterized in that: The beam splitter path includes, The optical path chamber is horizontally arranged, and along the horizontal direction of the optical path chamber are a galvanometer reflecting mirror, a semi-transparent and semi-reflective mirror, and a plane mirror, which are parallel to each other and tilted at 45°. The reflective surface of the semi-transparent mirror is used to reflect the processing laser and then reflect it onto the workpiece after passing through the galvanometer mirror. The transmission surface of the semi-transparent mirror is used to project the laser reflected after spot welding and then reflect it onto the coaxial camera after passing through the plane mirror.

3. The image acquisition optical path structure for laser welding according to claim 2, characterized in that: An upward-opening inlet is provided in the middle of the optical path chamber, and a first outlet and a second outlet with opposite openings are provided at both ends of the optical path chamber, with the first outlet opening downwards. The reflecting surface of the galvanometer mirror is positioned directly opposite the first exit port; the reflecting surface of the semi-transparent mirror is positioned directly opposite the entrance port; and the reflecting surface of the plane mirror is positioned directly opposite the second exit port.

4. The image acquisition optical path structure for laser welding according to claim 3, characterized in that: A focusing field lens is provided at the first emission port to focus the laser reflected by the galvanometer mirror onto the welding point of the workpiece to be processed.

5. A laser welding apparatus, characterized in that: Including the image acquisition optical path structure for laser welding as described in any one of claims 1-4, it further includes, A frame on which a reference platform is provided, and a fixture for fixing the workpiece to be processed is provided on the reference platform; A three-dimensional motion module is mounted on a frame, and a laser galvanometer module and / or a coaxial camera are fixed on the three-dimensional motion module.

6. The laser welding apparatus according to claim 5, characterized in that: It also includes, A global camera, mounted on the frame and / or laser galvanometer module, is used to acquire a global image of the workpiece to be processed in order to identify welding points.

7. The laser welding apparatus according to claim 6, characterized in that: A laser rangefinder is installed on one side of the focusing lens. Its measuring surface is at the same level as the lens of the focusing lens, and it is used to measure the distance in real time to the welding area of ​​the workpiece to be processed.

8. The laser welding apparatus according to claim 7, characterized in that: It also includes a fume extraction device, located at the bottom of the laser galvanometer module, used to absorb the fumes generated during welding; The exhaust port of the smoke extraction device is connected to the purifier via a flexible hose.

Images