High-precision flexible laser welding production line based on visual recognition and welding process thereof

Abstract

The high-precision flexible laser welding production line based on visual recognition comprises a rack and a three-partition wire groove formed in the rack, and the three-partition wire groove is used for installing a high-voltage cable, a low-voltage cable and a signal cable. A conveying system, a motion control system, a laser welding system, a closed-loop cooling system and a control system which are in butt joint with a CCS line body conveying device are arranged on the rack, the cooling system comprises a cooling-water machine and a nitrogen flow meter, deionized water is adopted as a cooling medium, the water temperature control precision is + / -1 DEG C, the cooling flow is 5-20 L / min, and the control system is connected with the CCS line body conveying device. The water temperature, water pressure and flow real-time monitoring and alarming functions are achieved, and laser output is automatically cut off when cooling is abnormal. The modular chemical station can support flexible switching between single-machine operation of a sample line and line connection operation of a mass production line by increasing, decreasing and adjusting the welding process, a special line does not need to be built for a single product, the requirement for collinear production of multiple products is met, and the production line modification cost is greatly reduced.

Description

Technical Field

[0001] This invention relates to the field of laser welding technology, specifically to a high-precision flexible laser welding production line based on visual recognition and its welding process. Background Technology

[0002] Current laser welding production lines have significant shortcomings in terms of flexible production, welding precision, quality stability, and intelligent control: First, they lack flexibility and adaptability, often designed as dedicated lines for single products. Adding or removing workstations or switching between sample line standalone operation and mass production line operation requires extensive modifications, resulting in high costs and low efficiency, making it difficult to meet the needs of multi-product simultaneous production. Second, welding precision and quality are difficult to guarantee. The positioning accuracy of the motion system and visual recognition accuracy are insufficient, and the nickel sheet position cannot be accurately and automatically corrected, easily leading to problems such as weld point misalignment, incomplete welds, and missed welds. Furthermore, the welding peel force, shear force, and stability often fail to meet standards, and weld points are prone to discoloration such as yellow or black, as well as burrs and weld explosion defects. Third, safety protection and intelligence are insufficient. Cooling systems often lack closed-loop monitoring, making it difficult to promptly shut off laser protection equipment in case of abnormalities. Laser protection measures are inadequate, posing a risk of leakage. At the same time, there is a lack of deep integration with the MES system, making it difficult to trace welding parameters and quality data. Operation permission management is not standardized, making it difficult to meet the requirements of high efficiency, safety, and traceability in precision welding. Summary of the Invention

[0003] To overcome the shortcomings of existing technical solutions, this invention provides a high-precision flexible laser welding production line based on visual recognition and its welding process, which can effectively solve the problems raised in the background technology.

[0004] The technical solution adopted by this invention to solve its technical problem is:

[0005] A high-precision flexible laser welding production line based on visual recognition includes a frame and a three-section cable tray on the frame. The three-section cable tray is used to install high-voltage cables, low-voltage cables and signal cables. The frame is equipped with a conveying system, a motion control system, a laser welding system, a closed-loop cooling system and a control system that are connected to the CCS line conveying device. The cooling system includes a chiller and a nitrogen flow meter. The cooling medium is deionized water. The water temperature control accuracy is ±1℃ and the cooling flow rate is 5-20L / min. It has real-time monitoring and alarm functions for water temperature, water pressure and flow rate. The laser output is automatically cut off when the cooling is abnormal.

[0006] The conveying system consists of a double-speed chain head, a double-speed chain tail, a lower double-speed chain return mechanism, an upper cooling double-speed chain feeding mechanism, a pallet lifting cylinder, a movable pallet, and a pallet positioning and blocking mechanism, which realizes automatic feeding, positioning, and unloading of welding products.

[0007] The motion control system includes an X-axis adjustment module, a Y-axis adjustment module, and a Z-axis adjustment module. The X-axis adjustment module and the Y-axis adjustment module are horizontally assembled, and the Z-axis adjustment module is vertically positioned above the X-axis adjustment module.

[0008] The laser welding system includes two laser heads, a laser generator, a collimating field mirror galvanometer assembly, a fiber optic follower mechanism, and a fiber optic rotation mechanism. The two laser heads are respectively mounted on the lower end of the Z-axis adjustment module to realize synchronous operation of dual laser heads on one machine and 6-axis joint control, and is equipped with an anti-collision function.

[0009] The visual recognition system consists of a flying camera, a coaxial camera, a camera light source, and a height measurement module. It has a recognition accuracy of ±0.05mm and can monitor and locate the welding part in real time and automatically correct the welding trajectory. It can detect the positional deviation of the welded nickel sheet. When the deviation tolerance exceeds ±0.3mm, it will automatically correct the welding and automatically alarm when it exceeds ±2mm.

[0010] As a further description of the above technical solution, the welding head movement speed of the motion control system is continuously adjustable within the range of 5-500 mm / s, and the speed fluctuation range is ≤±3%; the motion control system supports programming of various welding trajectories such as straight lines, arcs, and curves.

[0011] As a further description of the above technical solution, the height measurement module of the visual recognition system can set the height measurement benchmark value and limit value, monitor the welding Z-axis height in real time and feed it back to the control system; the flying camera and the coaxial camera work together to achieve accurate capture of the welding point, and each welding point can be adjusted individually.

[0012] As a further description of the above technical solution, the laser welding system also includes an air blowing head, a pressure plate cylinder, and a pressure plate force adjustment mechanism; the air blowing head is used for air blowing protection during the welding process, and the pressure plate cylinder, in conjunction with the pressure plate force adjustment mechanism, achieves precise clamping of the product during welding to avoid welding displacement.

[0013] As a further description of the above technical solution, the conveying system supports simultaneous welding at multiple workstations or continuous welding in an assembly line manner, and can switch working modes according to production needs and with reference to the product CT table; the production line is also equipped with a welding dust collection mechanism to collect the fumes generated during the welding process.

[0014] A welding process for a high-precision flexible laser welding production line based on visual recognition includes the following steps:

[0015] Step S1: Loading and positioning: The product to be welded is conveyed to the movable pallet by the cooling double-speed chain feeding mechanism of the conveying system. The pallet lifting cylinder lifts the movable pallet, the pallet positioning and blocking mechanism positions the product, and the motion control system drives the X, Y, and Z axis adjustment modules to move the laser welding system to the position to be welded.

[0016] Step S2: Visual Inspection and Trajectory Correction: The camera light source of the visual recognition system is turned on, and the flying camera or coaxial camera acquires images of the welding area to identify the positional deviation of the welded nickel sheet; when the deviation tolerance is ≤ ±0.3mm, the control system automatically corrects the welding trajectory; when the deviation tolerance is > ±2mm, the system automatically alarms and continues after manual correction and positioning; when the deviation tolerance is within the range of ±0.3mm to ±2mm, automatic correction or manual confirmation is selected according to preset parameters.

[0017] Step S3: Laser welding: Turn on the cooling system, the chiller controls the water temperature within the set range, and the nitrogen flow meter adjusts the nitrogen flow rate; the control system calls the preset welding process parameters, drives the two laser heads to achieve 6-axis joint control welding, the air blowing head blows air for protection during the welding process, and the welding dust collection mechanism collects the fumes.

[0018] Step S4: Welding quality inspection and data recording: After welding is completed, the visual recognition system will collect the weld point image again to determine whether there is any cold weld, missing weld, discoloration, burr, blast weld, or burn-through. The system will also detect that the weld point offset is less than 0.15mm and the welded threads are visually clear. The control system will record the number of welding operations, OK / NG results, single run time, and save the fixed / flying images.

[0019] Step S5: Data Upload to MES: The control system packages the welding parameters, image data, and OK / NG results of a single product according to time, generates a traceability file with a QR code, and uploads it to the MES system;

[0020] Step S6: Unloading and Mode Switching: The lower speed chain return mechanism of the conveyor system transports the welded products to the next process; when the process needs to be switched, workstations can be added or removed through modular workstation components; when the operation mode needs to be switched, the control system switches to single machine operation or mass production line connection operation.

[0021] As a further description of the above technical solution, in step S3, the welding process parameters satisfy: peel force of the welded product > 100N, shear force > 600N, weld peel force stability CPK > 1.67, and weld residue > 2 / 3.

[0022] As a further description of the above technical solution, the process also includes a periodic calibration step: after every 1000 welding runs, the positioning accuracy of the motion control system and the recognition accuracy of the vision recognition system are calibrated using a standard template, wherein the positioning accuracy of the motion control system is ≤ ±0.02mm and the recognition accuracy of the vision recognition system is ±0.05mm, and the calibration data is recorded in the operation log and uploaded to the MES.

[0023] Compared with the prior art, the beneficial effects of the present invention are:

[0024] The present invention discloses a high-precision flexible laser welding production line based on visual recognition and its welding process, which has at least one of the following beneficial effects during use:

[0025] Firstly, it boasts strong flexibility and adaptability. The modular workstations can adjust welding processes by adding or removing components, supporting flexible switching between standalone operation on sample lines and connected operation on mass production lines. This eliminates the need for dedicated lines for single products, meeting the needs of multi-product simultaneous production and significantly reducing production line modification costs. Secondly, it offers high welding precision and quality. The motion system's positioning accuracy is ≤±0.02mm, and the visual recognition accuracy is ±0.05mm. It can automatically correct nickel sheet offset within ±0.3mm, ensuring weld point offset <0.15mm. Dual laser heads with 6-axis linkage, combined with air blowing protection and precise clamping, and automatic laser cutoff in case of cooling system malfunctions, ensure welding peel force >100N, shear force >600N, and CPK >1.67, eliminating defects such as incomplete welds and discoloration. Thirdly, it excels in safety and intelligence. A fully enclosed IP54 enclosure and laser interlocking device ensure safety. The control system integrates MES, data is traceable with QR codes, and three-level access control and counting logs facilitate management. Multi-station operation and automatic loading / unloading further improve production efficiency. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the overall structure of a high-precision flexible laser welding production line based on visual recognition according to the present invention;

[0027] Figure 2 This is a cross-sectional structural diagram of a high-precision flexible laser welding production line based on visual recognition according to the present invention.

[0028] Figure 3 For the present invention Figure 2 Schematic diagram of part A in the middle.

[0029] Numbering on the map:

[0030] 1. Lower speed chain recirculation; 2. Upper speed chain feeding; 3. Three-section trough; 4. Industrial control computer; 5. Pallet lifting cylinder; 6. Movable pallet; 7. Speed ​​chain head; 8. Speed ​​chain tail; 9. Pallet positioning block; 10. X-axis adjustment module; 11. Y-axis adjustment module; 12. Z-axis adjustment module; 13. Air blowing head; 14. Pressure plate cylinder; 15. Camera light source; 16. Flying camera; 17. Collimating field mirror galvanometer assembly; 18. Air blowing protection; 19. Fiber optic follow-up; 20. Fiber optic rotation; 21. Protective door; 22. Welding dust extraction; 23. Coaxial camera; 24. Nitrogen flow meter; 25. Pressing force adjustment; 26. Laser generator; 27. Chiller. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] like Figures 1-3 As shown, this invention provides a high-precision flexible laser welding production line based on visual recognition. The three-section cable tray 3 is used to install high-voltage cables, low-voltage cables, and signal cables. It includes a conveying system, a motion control system, a laser welding system, a closed-loop cooling system, and a control system that are connected to the CCS line conveying device. The cooling system includes a chiller 27 and a nitrogen flow meter 24. The cooling medium is deionized water, with a water temperature control accuracy of ±1℃ and a cooling flow rate of 5-20L / min. It has real-time monitoring and alarm functions for water temperature, water pressure, and flow rate, and automatically cuts off the laser output when the cooling is abnormal.

[0033] After the welded product is conveyed to the movable pallet 6 via the upper-cooling double-speed chain feeding mechanism 2, the pallet lifting cylinder 5 lifts the movable pallet 6 to the welding height. At the same time, the pallet positioning and blocking mechanism 9 precisely limits the product (ensuring no displacement during subsequent welding). After welding is completed, the lower-speed chain return mechanism 1 conveys the product to the next process. It supports two modes: "multi-station simultaneous welding" or "continuous assembly line welding," which can be flexibly switched according to the product CT table (cycle time) to adapt to different production capacity requirements.

[0034] The system employs a closed-loop water-cooling mode, using deionized water as the cooling medium. Water temperature control accuracy is ±1℃, and the cooling flow rate is maintained at 5-20L / min. Water temperature, pressure, and flow rate are monitored in real time. If any abnormality occurs (such as excessive water temperature or insufficient water pressure), the system immediately cuts off the laser output to protect critical components such as the laser and optical devices. The laser working area is equipped with laser protective glass to prevent laser leakage and burns to operators. A "laser safety interlock device" is installed; when the protective door 21 is opened, the laser output is immediately cut off and an audible and visual alarm is triggered, forming a double safety guarantee.

[0035] The conveying system consists of a double-speed chain head 7, a double-speed chain tail 8, a lower double-speed chain return mechanism 1, an upper cooling double-speed chain feeding mechanism 2, a pallet lifting cylinder 5, a movable pallet 6, and a pallet positioning and blocking mechanism 9, which realizes automatic feeding, positioning, and unloading of welding products.

[0036] The motion control system includes an X-axis adjustment module 10, a Y-axis adjustment module 11, and a Z-axis adjustment module 12. The X-axis adjustment module 10 and the Y-axis adjustment module 11 are horizontally assembled, and the Z-axis adjustment module 12 is vertically positioned above the X-axis adjustment module 10.

[0037] Employing a high-precision linear motor and rangefinder feedback system, the welding worktable achieves a positioning accuracy of ≤±0.02mm and a repeatability of ≤±0.01mm. When the Z-axis adjustment module 12 is in a non-safe position, the X-axis adjustment module 10 and Y-axis adjustment module 11 are locked, and the X, Y, and Z axes can be individually set with soft limits. Through real-time feedback from the linear motor and rangefinder, the welding worktable achieves a positioning accuracy of ≤±0.02mm and a repeatability of ≤±0.01mm, meeting the precision welding requirements of the CCS production line.

[0038] The laser welding system includes two laser heads, a laser generator 26, a collimating field mirror galvanometer assembly 17, an optical fiber follower mechanism 19, and an optical fiber rotation mechanism 20. The two laser heads are respectively mounted on the lower end of the Z-axis adjustment module 12 to realize synchronous operation of dual laser heads and 6-axis joint control, and is equipped with an anti-collision function.

[0039] The visual recognition system consists of a flying camera 16, a coaxial camera 23, a camera light source 15, and a height measurement module. It has a recognition accuracy of ±0.05mm and can monitor and locate the welding part in real time and automatically correct the welding trajectory. It can detect the positional deviation of the welded nickel sheet. When the deviation tolerance exceeds ±0.3mm, it will automatically correct the welding and automatically alarm when it exceeds ±2mm.

[0040] The safety protection system of this embodiment adopts a fully enclosed structure with an outer shell protection level of not less than IP54; the laser working area is equipped with laser protective glass that conforms to GB7247.1 standard, and is equipped with a laser safety interlock device. When the protective door 21 is opened, the laser output is immediately cut off and an audible and visual alarm is triggered.

[0041] Modular workstation components: All workstations are modular in structure, and the welding process can be adjusted by adding or removing workstations. They can also achieve flexible switching between single-machine operation on the sample line and connected operation on the mass production line.

[0042] The control system includes an industrial computer 4 and a touch screen human-machine interface. The industrial computer 4 has three operating modes: fixed shooting, flying shooting, and fixed position. Fixed shooting / flying shooting images can be selectively saved and uploaded to MES. The welding parameters and image data of a single product can be packaged and uploaded to MES according to time and OK / NG categories (data is accompanied by QR codes for easy traceability). It is also equipped with encrypted machine locking function and pop-up reminder function the day before locking.

[0043] The touchscreen human-machine interface supports three levels of login permissions (each permission has an independent password and configuration content) and can store no less than 200 sets of welding process parameters.

[0044] With an accuracy of ±0.05mm, the system uses a camera to capture real-time images of the welding area and detects the positional shift of the nickel sheet.

[0045] Offset tolerance ≤ ±0.3mm: The control system automatically corrects the welding trajectory without manual intervention;

[0046] Offset tolerance > ±2mm: The system will automatically alarm and restart after manual correction and positioning.

[0047] Offset tolerance is ±0.3mm to ±2mm: Select "Automatic Correction" or "Manual Confirmation" according to the preset parameters.

[0048] Furthermore, the welding head movement speed of the motion control system is continuously adjustable within the range of 5-500 mm / s, and the speed fluctuation range is ≤±3%; the motion control system supports programming of various welding trajectories such as straight lines, circular arcs, and curves.

[0049] Welding paths can be generated through teach programming or by importing CAD original drawings. The welding head movement speed is continuously adjustable within the range of 5-500mm / s, with speed fluctuations ≤±3% (ensuring uniform laser energy distribution). It supports programming of straight lines, arcs, curves, and other trajectories, and welding paths can be generated through "teach programming" or "CAD original drawing import." When the Z-axis is not in a safe position, the X / Y axes automatically lock (except for handwheel operation), and the X / Y / Z axes can be individually set with soft limits to prevent equipment collisions. It drives two laser heads to achieve 6-axis synchronized operation and is equipped with an anti-collision function (to prevent equipment damage caused by programming / trajectory errors).

[0050] Furthermore, the height measurement module of the visual recognition system can be set with a height reference value and a limit value, monitor the welding Z-axis height in real time and feed it back to the control system; the flying camera 16 and the coaxial camera 23 work together to achieve accurate capture of the welding point, and each welding point can be adjusted individually.

[0051] The control system also has IO judgment function, counting / prompt function and operation log query function; the operation log can display the operation process of each time period, the counting / prompt function includes welding number statistics, OK number statistics, NG number statistics and statistics clearing function, and can also display working time and single run time.

[0052] The control system supports barcode scanning / reading functions, which can match the barcode information of the welding product with the welding parameters to achieve a one-to-one correspondence between the product and the data; and the control system can control conventional galvanometers and laser controllers on the market, and supports programming of various welding patterns.

[0053] The height measurement module can be set with "height reference value" and "limit value", monitors the welding Z-axis height in real time and feeds it back to the control system; it supports individual debugging of a single welding point to ensure weld consistency.

[0054] Furthermore, the laser welding system also includes an air blowing head 13, a pressure plate cylinder 14, and a pressure plate force adjustment mechanism 25; the air blowing head 13 is used for air blowing protection 18 during the welding process, and the pressure plate cylinder 14, in conjunction with the pressure plate force adjustment mechanism 25, achieves precise clamping of the product during welding and avoids welding displacement.

[0055] After the control system calls the preset process parameters (power, speed, duty cycle), the dual laser heads simultaneously weld the product in different areas. During the welding process, the air blowing head 13 provides air blowing protection 18 (reducing weld oxidation), the pressure plate cylinder 14 and the pressure plate force adjustment mechanism 25 precisely press the product (avoiding welding displacement), and the welding dust extraction mechanism 22 collects fumes in real time (ensuring environmental and weld cleanliness). It supports control of conventional galvanometers and laser controllers on the market, and can program various welding patterns to adapt to the welding needs of different products.

[0056] Furthermore, the conveying system supports simultaneous welding at multiple workstations or continuous welding in an assembly line manner, and the working mode can be switched according to production needs and with reference to the product CT table; the production line is also equipped with a welding dust extraction mechanism 22, which is used to collect the fumes generated during the welding process.

[0057] A welding process for a high-precision flexible laser welding production line based on visual recognition includes the following steps:

[0058] Step S1: Loading and positioning: The product to be welded is conveyed to the movable pallet 6 by the upper cooling double speed chain feeding mechanism 2 of the conveying system. The pallet lifting cylinder 5 lifts the movable pallet 6, the pallet positioning blocking mechanism 9 positions the product, and the motion control system drives the X, Y, Z axis adjustment module 12 to move the laser welding system to the position to be welded.

[0059] Feeding: The upper-cooled double-speed chain feeding mechanism 2 conveys the product to be welded to the movable pallet 6;

[0060] Positioning: Pallet lifting cylinder 5 lifts the movable pallet 6, and pallet positioning blocking mechanism 9 limits the product position;

[0061] Alignment: The motion control system drives the X / Y / Z axis adjustment module 12 to move the laser welding system to the position to be welded (positioning accuracy ≤ ±0.02mm).

[0062] Step S2: Visual Inspection and Trajectory Correction: The camera light source 15 of the visual recognition system is turned on, and the flying camera 16 or coaxial camera 23 acquires images of the welding area to identify the positional deviation of the welded nickel sheet; when the deviation tolerance is ≤ ±0.3mm, the control system automatically corrects the welding trajectory; when the deviation tolerance is > ±2mm, the system automatically alarms and continues after manual correction and positioning; when the deviation tolerance is within the range of ±0.3mm to ±2mm, automatic correction or manual confirmation is selected according to preset parameters.

[0063] Image acquisition: Camera light source 15 is turned on, and flying camera 16 / coaxial camera 23 acquires images of the welding area;

[0064] Offset detection: Identify nickel sheet position offset and perform different operations according to the tolerance range:

[0065] Offset ≤ ±0.3mm: Automatic correction of welding trajectory;

[0066] Offset > ±2mm: Automatic alarm, restart after manual correction;

[0067] Offset ±0.3mm~±2mm: Select "Automatic Correction" or "Manual Confirmation" according to the preset parameters;

[0068] Height feedback: The height measurement module monitors the welding Z-axis height and feeds the data back to the control system.

[0069] Step S3: Laser welding: Turn on the cooling system, chiller 27 controls the water temperature within the set range, nitrogen flow meter 24 adjusts the nitrogen flow rate; the control system calls the preset welding process parameters, drives the two laser heads to achieve 6-axis joint control welding, during the welding process, the air blowing head 13 blows air protection 18, and the welding dust collection mechanism 22 collects the smoke and dust.

[0070] Cooling start-up: The closed-loop cooling system is turned on, the chiller 27 controls the water temperature within the set range (accuracy ±1℃), and the nitrogen flow meter 24 adjusts the nitrogen flow rate;

[0071] Parameter call: The control system calls preset process parameters (welding power, speed, duty cycle);

[0072] Synchronous welding: Drives dual laser heads to achieve 6-axis joint control welding, with air blowing head 13 for air blowing protection 18, and welding dust collection mechanism 22 to collect fumes;

[0073] Anti-displacement protection: The pressure plate cylinder 14 + pressure plate force adjustment 25 mechanism continuously presses the product.

[0074] Step S4: Welding quality inspection and data recording: After welding is completed, the visual recognition system will collect the weld point image again to determine whether there is any cold weld, missing weld, discoloration, burr, blast weld, or burn-through. The system will also detect that the weld point offset is less than 0.15mm and the welded threads are visually clear. The control system will record the number of welding operations, OK / NG results, single run time, and save the fixed / flying images.

[0075] Secondary inspection: The visual recognition system re-captures images of the solder joints, and the inspection indicators include:

[0076] No cold solder joints, missing solder joints, or insufficient solder joints;

[0077] The appearance is free of any discoloration such as yellow, blue, or black.

[0078] Solder joint offset < 0.15mm, smooth and free of burrs / fractures / burn-through;

[0079] The welded threads are clearly visible.

[0080] Data logging: Records the number of welding attempts, OK / NG results, single run time, and saves fixed-shot / flying-shot images.

[0081] Step S5: Data Upload to MES: The control system packages the welding parameters, image data, and OK / NG results of a single product according to time, generates a traceability file with a QR code, and uploads it to the MES system;

[0082] The control system packages the "welding parameters + image data + OK / NG results" of individual products according to time, generates traceability files with QR codes, and uploads them to the factory's MES system for easy production management and historical traceability.

[0083] (Welding parameters: power, speed, duty cycle, distance measurement and Z-axis height.)

[0084] (Preset welding process parameters: welding power, welding speed, duty cycle.)

[0085] Step S6: Unloading and Mode Switching: The lower speed chain return mechanism of the conveyor system transports the welded products to the next process; when the process needs to be switched, workstations are added or removed through modular workstation components; when the operation mode needs to be switched, the control system switches to single machine operation or mass production line connection operation.

[0086] Material feeding: The double-speed chain return mechanism 1 transports the welded product to the next process;

[0087] Flexible switching: When the process needs to be adjusted, workstations can be added or removed through "modular workstation components"; when the production capacity mode needs to be changed, "sample line stand-alone operation" or "mass production line connection operation" can be switched.

[0088] Furthermore, in step S3, the welding process parameters meet the following requirements: peel force of the welded product > 100N, shear force > 600N, weld peel force stability CPK > 1.67, and weld residue > 2 / 3.

[0089] Furthermore, the process also includes a periodic calibration step: after every 1000 welding runs, the positioning accuracy of the motion control system and the recognition accuracy of the vision recognition system are calibrated using a standard template. The positioning accuracy of the motion control system is ≤ ±0.02mm, and the recognition accuracy of the vision recognition system is ±0.05mm. The calibration data is recorded in the operation log and uploaded to the MES.

[0090] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A high-precision flexible laser welding production line based on visual recognition, comprising a frame and a three-section cable tray mounted on the frame, wherein the three-section cable tray is used to install high-voltage cables, low-voltage cables, and signal cables, characterized in that: The frame is equipped with a conveying system, a motion control system, a laser welding system, a closed-loop cooling system, and a control system that are connected to the CCS line conveying device. The cooling system includes a chiller and a nitrogen flow meter. The cooling medium is deionized water, with a water temperature control accuracy of ±1℃ and a cooling flow rate of 5-20L / min. It has real-time monitoring and alarm functions for water temperature, water pressure, and flow rate, and automatically cuts off the laser output when the cooling is abnormal. The conveying system consists of a double-speed chain head, a double-speed chain tail, a lower double-speed chain return mechanism, an upper cooling double-speed chain feeding mechanism, a pallet lifting cylinder, a movable pallet, and a pallet positioning and blocking mechanism, which realizes automatic feeding, positioning, and unloading of welding products. The motion control system includes an X-axis adjustment module, a Y-axis adjustment module, and a Z-axis adjustment module. The X-axis adjustment module and the Y-axis adjustment module are horizontally assembled, and the Z-axis adjustment module is vertically positioned above the X-axis adjustment module. The laser welding system includes two laser heads, a laser generator, a collimating field mirror galvanometer assembly, a fiber optic follower mechanism, and a fiber optic rotation mechanism. The two laser heads are respectively mounted on the lower end of the Z-axis adjustment module to realize synchronous operation of dual laser heads on one machine and 6-axis joint control, and is equipped with an anti-collision function. The visual recognition system consists of a flying camera, a coaxial camera, a camera light source, and a height measurement module. It has a recognition accuracy of ±0.05mm and can monitor and locate the welding part in real time and automatically correct the welding trajectory. It can detect the positional deviation of the welded nickel sheet. When the deviation tolerance exceeds ±0.3mm, it will automatically correct the welding and automatically alarm when it exceeds ±2mm.

2. The high-precision flexible laser welding production line based on visual recognition according to claim 1, characterized in that: The motion control system allows for continuous adjustment of the welding head movement speed within the range of 5-500 mm / s, with a speed fluctuation range of ≤±3%. The motion control system supports programming for various welding trajectories, including straight lines, circular arcs, and curves.

3. The high-precision flexible laser welding production line based on visual recognition according to claim 1, characterized in that: The height measurement module of the visual recognition system can be set with a reference value and a limit value, monitor the welding Z-axis height in real time and feed it back to the control system; the flying camera and the coaxial camera work together to achieve accurate capture of the welding point, and each welding point can be adjusted individually.

4. The high-precision flexible laser welding production line based on visual recognition according to claim 1, characterized in that: The laser welding system also includes an air blowing head, a pressure plate cylinder, and a pressure plate force adjustment mechanism; the air blowing head is used for air blowing protection during the welding process, and the pressure plate cylinder, in conjunction with the pressure plate force adjustment mechanism, achieves precise clamping of the product during welding to avoid welding displacement.

5. The high-precision flexible laser welding production line based on visual recognition according to claim 1, characterized in that: The conveying system supports simultaneous welding at multiple workstations or continuous welding in an assembly line manner, and the working mode can be switched according to production needs and with reference to the product CT table; the production line is also equipped with a welding dust collection mechanism to collect the fumes generated during the welding process.

6. A welding process for a high-precision flexible laser welding production line based on visual recognition, characterized in that: Includes the following steps: Step S1: Loading and positioning: The product to be welded is conveyed to the movable pallet by the cooling double-speed chain feeding mechanism of the conveying system. The pallet lifting cylinder lifts the movable pallet, the pallet positioning and blocking mechanism positions the product, and the motion control system drives the X, Y, and Z axis adjustment modules to move the laser welding system to the position to be welded. Step S2: Visual Inspection and Trajectory Correction: The camera light source of the visual recognition system is turned on, and the flying camera or coaxial camera acquires images of the welding area to identify the positional deviation of the welded nickel sheet; when the deviation tolerance is ≤ ±0.3mm, the control system automatically corrects the welding trajectory; when the deviation tolerance is > ±2mm, the system automatically alarms and continues after manual correction and positioning; when the deviation tolerance is within the range of ±0.3mm to ±2mm, automatic correction or manual confirmation is selected according to preset parameters. Step S3: Laser welding: Turn on the cooling system, the chiller controls the water temperature within the set range, and the nitrogen flow meter adjusts the nitrogen flow rate; the control system calls the preset welding process parameters, drives the two laser heads to achieve 6-axis joint control welding, the air blowing head blows air for protection during the welding process, and the welding dust collection mechanism collects the fumes. Step S4: Welding quality inspection and data recording: After welding is completed, the visual recognition system will collect the weld point image again to determine whether there is any cold weld, missing weld, discoloration, burr, blast weld, or burn-through. The system will also detect that the weld point offset is less than 0.15mm and the welded threads are visually clear. The control system will record the number of welding operations, OK / NG results, single run time, and save the fixed / flying images. Step S5: Data Upload to MES: The control system packages the welding parameters, image data, and OK / NG results of a single product according to time, generates a traceability file with a QR code, and uploads it to the MES system; Step S6: Unloading and Mode Switching: The lower speed chain return mechanism of the conveyor system transports the welded products to the next process; when the process needs to be switched, workstations can be added or removed through modular workstation components; when the operation mode needs to be switched, the control system switches to single machine operation or mass production line connection operation.

7. The welding process for a high-precision flexible laser welding production line based on visual recognition according to claim 6, characterized in that: In step S3, the welding process parameters meet the following requirements: peel force of the welded product > 100N, shear force > 600N, weld peel force stability CPK > 1.67, and weld residue > 2 / 3.

8. The welding process for a high-precision flexible laser welding production line based on visual recognition according to claim 6, characterized in that: The process also includes a periodic calibration step: after every 1000 welding runs, the positioning accuracy of the motion control system and the recognition accuracy of the vision recognition system are calibrated using a standard template. The positioning accuracy of the motion control system is ≤ ±0.02mm, and the recognition accuracy of the vision recognition system is ±0.05mm. The calibration data is recorded in the operation log and uploaded to the MES.

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