Laser fusing device and method for ultrafast laser pre-treatment of magnesium-lithium welding wire surface

Abstract

The application discloses a kind of magnesium lithium welding wire surface ultrafast laser pretreatment laser fuse device and method, including welding torch, welding wire supply device and fiber laser head, further include: fiber laser fuse manufacturing system, fiber laser fuse manufacturing system is used to output fiber laser, realize welding wire melting, the molten pool of stable welding piece additive process;Red-green laser layering cleaning system is used to output the high stability ultra-short pulse laser of triangular distribution, realizes the laser cleaning of magnesium lithium alloy welding wire surface;Cleaning process monitoring system is used for welding wire surface quality state feedback;Waste gas treatment system is used to collect the waste gas waste generated in cleaning process;Low-temperature atmosphere system is used to ensure that cleaning process is in low-temperature environment, avoid magnesium alloy dust spontaneous combustion.

Description

Technical Field

[0001] This invention belongs to the field of laser welding technology, specifically relating to a laser welding wire device and method for ultrafast laser pretreatment of the surface of magnesium-lithium welding wire. Background Technology

[0002] Magnesium-lithium alloys, as ultralight structural materials, combine low density, high specific strength, and good damping, making them suitable for spacecraft skins, drones, and portable electronic structural components. However, their high chemical reactivity makes them prone to forming dense oxide films and adsorbing oil and dust, leading to poor wettability, increased porosity / cracks, and decreased interlayer bonding strength during laser filament additive manufacturing.

[0003] Existing chemical, sandblasting, or mechanical grinding cleaning methods suffer from low efficiency, substrate damage, secondary contamination, and difficulty in online implementation. Laser cleaning offers advantages such as non-contact, positioning, and automation; however, nanosecond-level cleaning involves significant thermal effects and raises concerns about residual re-oxidation. Furthermore, the types of oxides on the surface of magnesium-lithium welding wires vary, resulting in different cleaning difficulties. Summary of the Invention

[0004] The purpose of this invention is to provide a laser melting device and method for ultrafast laser pretreatment of magnesium-lithium welding wire surface to solve the above-mentioned problems.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a laser welding wire device for ultrafast laser pretreatment of magnesium-lithium welding wire surface, comprising a welding torch, a welding wire supply device, and a fiber laser head, and further comprising:

[0006] The fiber laser filament manufacturing system specifically includes a fiber laser workpiece disposed at the bottom of the fiber laser head and a transmission fiber connected to the input end of the fiber laser head, and the fiber laser workpiece is connected to the laser generating device through the transmission fiber.

[0007] The red-green laser layer cleaning system specifically includes cleaning red laser 1, cleaning red laser 2, cleaning red laser 3, cleaning green laser 1, cleaning green laser 2 and cleaning green laser 3, and the output ends are respectively connected to the welding gun through transmission optical fibers 2, 3, 4, 5, 6 and 7.

[0008] The exhaust gas cleaning system is installed at the input end of the welding torch and specifically includes air blowing device 1, air blowing device 2, air blowing device 3, air blowing device 4, air supply device 1, air supply device 2, air extraction device 1, and air extraction device 2.

[0009] The control system specifically includes a control system integration device, which is connected to the input terminals of the welding torch, the cleaning red laser 2, the cleaning red laser 1, the cleaning red laser, and the laser generating equipment via data transmission line, output signal line 3, and output signal line 5, respectively. The output terminal of the control system integration device is also connected to an output signal line 4, and the output terminal of the output signal line 4 is connected to a welding wire supply device. The welding wire supply device is connected to the welding torch via a welding wire feeding channel.

[0010] Preferably, the exhaust gas cleaning system is further provided with galvanometer laser head one, galvanometer laser head two, and galvanometer laser head three. The output ends of the cleaning red laser one, cleaning red laser two, and cleaning red laser three are respectively connected to galvanometer laser head one, galvanometer laser head two, and galvanometer laser head three, and the three form a 120-degree angle pointing towards the center of the focal welding wire for cleaning.

[0011] Preferably, the waste gas cleaning system is further equipped with monitoring camera one, monitoring camera two, and monitoring camera three, which are at a 120-degree angle to the center of the focus welding wire for real-time monitoring.

[0012] Preferably, the welding wire supply device includes a clamping block, a welding wire spool, a rotating shaft, and a welding wire feeding channel. The welding wire spool is mounted on the rotating shaft, which is mounted on the clamping block. The welding wire feeding channel is used to transmit welding wire between the welding wire spool and the welding torch.

[0013] Preferably, the system also includes a cryogenic atmosphere system, specifically comprising an argon cylinder, a compressed gas cylinder, a liquid nitrogen cylinder, and a temperature sensor. The temperature sensor is installed inside the waste gas cleaning system to detect the internal temperature. The argon cylinder is connected to the welding torch via a pressure reducing valve and a mass flow controller through a gas supply pipe. The output end of the compressed gas cylinder is connected to a first, second, third, and fourth gas blowing device via gas supply pipes two and three, respectively. The liquid nitrogen cylinder is connected to the inside of the waste gas cleaning system via gas supply pipe four to control its internal temperature.

[0014] Preferably, the exhaust gas cleaning system at one end of the welding torch is further provided with two honeycomb-shaped pipes, which are respectively connected to the first and second extraction devices. This allows the negative pressure of the exhaust gas generated by the first and second extraction devices to be distributed on both sides of the welding wire. A conical groove block fixed to the inner wall of the welding torch is provided below the bottom honeycomb-shaped pipe. The conical groove block guides the sinking debris and collects it inside the honeycomb-shaped pipe.

[0015] Preferably, another honeycomb-shaped pipe is fitted with a secondary shell on its outer side, and the secondary shell has an opening for the passage of welding wire. The secondary shell is provided with a gas supply pipe five, and the gas supply pipe five is connected to a compressed gas cylinder for gas supply, so as to form a separate reflux system for secondary cleaning.

[0016] A laser-fused wire method for ultrafast laser pretreatment of magnesium-lithium welding wire surface, the specific steps of which are as follows:

[0017] S1. Start blowing, exchanging and extracting air to form a directional airflow, and check the dust collection and filtration differential pressure;

[0018] S2, Ventilation: Set the target temperature of the cavity according to the process specifications, and operate the low temperature and temperature sensor in a closed loop.

[0019] S3. Activate the control, monitoring, and laser system. Load the material and welding wire parameter files into the host computer and set the recording and alarm thresholds. Monitor the camera and lighting self-test, and complete the geometric calibration and time synchronization of the calibration board.

[0020] S4. Perform optical path and focus checks. Under analog output, collimate, split, reflect, and check the galvanometer channel of fiber laser and ultrafast laser to complete the focal length / spot position verification.

[0021] S5. Verify the geometric position of the wire feeder and welding head, and set the safety stroke and soft limit; verify the "light touch" positioning and zero return accuracy of the welding head under no-load conditions. Run the wire feeder without load and observe the consistency between the wire guide / pressure / feeder wheel meshing and the encoder pulses.

[0022] S6. Monitoring system—Red-Green laser layered cleaning system—Laser welding linkage exercise, no-load linkage: The wire feeding trajectory, cleaning galvanometer trajectory and camera acquisition sequence are consistent; low power / short time test on the sample to confirm that the camera can correctly distinguish circumferential oxidation differences and drive the three-way galvanometer differential cleaning; dust is carried in and extracted by directional airflow.

[0023] S7. Formal additive manufacturing: First, establish stable protective gas and target temperature and humidity conditions; initiate arcing with low power and short passes; monitor the synchronization of power / duty cycle / scanning trajectory and wire feed speed throughout the process; trigger interlock to stop in case of abnormality.

[0024] The technical effects and advantages of this invention are as follows: The oxidation status of different areas on the surface of magnesium-lithium welding wire is monitored in real time by the cleaning process monitoring system. Under the unified and coordinated control of the control system, the red-green laser layer cleaning laser generates green light and red light respectively to clean the oxides on the surface of the welding wire. After cleaning, the laser wire melting additive process is carried out, which can solve the problem of oxide formation on the surface of magnesium-lithium welding wire and poor weldability after being left for too long. Attached Figure Description

[0025] Figure 1This is a schematic diagram of the overall structure of the device according to Embodiment 1 of the present invention.

[0026] Figure 2 This is a diagram showing the location distribution of the air blowing device 1 and air blowing device 2 in Embodiment 1 of the present invention.

[0027] Figure 3 This is a diagram showing the location distribution of cameras used for real-time monitoring of the cleaning process in Embodiment 1 of the present invention.

[0028] Figure 4 This is a diagram showing the position distribution of the laser head in the red-green laser layer cleaning galvanometer of Embodiment 1 of the present invention.

[0029] Figure 5 This is a diagram showing the location distribution of the air blowing device three and air blowing device four in Embodiment 1 of the present invention.

[0030] Figure 6 This is an enlarged view of the optical path of the galvanometer laser head according to Embodiment 1 of the present invention.

[0031] Figure 7 The following is a detailed drawing of the cleaning device according to Embodiment 1 of the present invention.

[0032] Figure 8 This is a schematic diagram of the structure of Embodiment 2 of the present invention.

[0033] In the diagram: 11. Fiber laser component; 12. Transmission fiber optic cable 1;

[0034] 21. Cleaning red laser unit one; 22. Cleaning red laser unit two; 23. Cleaning red laser unit three; 24. Cleaning green laser unit one; 25. Cleaning green laser unit two; 26. Cleaning green laser unit three; 211. Transmission fiber two; 221. Transmission fiber three; 231. Transmission fiber four; 241. Transmission fiber five; 251. Transmission fiber six; 261. Transmission fiber seven;

[0035] 3. Fiber laser head;

[0036] 41. Galvanometer laser head one; 42. Galvanometer laser head two; 43. Galvanometer laser head three;

[0037] 51. Air blowing device one; 52. Air blowing device two; 53. Air blowing device three; 54. Air blowing device four; 55. Air supply device one; 56. Air supply device two; 57. Air extraction device one; 58. Air extraction device two;

[0038] 61. Monitoring camera one; 62. Monitoring camera two; 63. Monitoring camera three;

[0039] 71. Control system integration device; 711. Data transmission line; 712. Output signal line one; 713. Output signal line two; 714. Output signal line three; 715. Output signal line four; 716. Output signal line five;

[0040] 81. Argon cylinder; 82. Compressed gas cylinder; 83. Liquid nitrogen cylinder; 811. Gas pipeline one; 821. Gas pipeline two; 822. Gas pipeline three; 831. Gas pipeline four; 832. Temperature sensor;

[0041] 91. Clamping block; 92. Welding wire spool; 93. Rotating shaft; 94. Welding wire feed channel;

[0042] 10. Welding torch;

[0043] 13. Honeycomb-shaped channels;

[0044] 14. Gas pipeline five;

[0045] 15. Secondary shell;

[0046] 16. Laser generating equipment;

[0047] 17. Conical groove block. Detailed Implementation

[0048] 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.

[0049] This invention provides, for example Figures 1-8 The laser welding wire device shown in the figure, which performs ultrafast laser pretreatment on the surface of magnesium-lithium welding wire, includes a welding torch 10, a welding wire supply device, and a fiber laser head 3, and further includes:

[0050] The fiber laser filament manufacturing system specifically includes a fiber laser workpiece 11 disposed at the bottom of the fiber laser head 3 and a transmission fiber 12 connected to the input end of the fiber laser head 3 and connected to the laser generating device 16 through the transmission fiber 12.

[0051] The red-green laser layer cleaning system specifically includes a red laser 1 (21), a red laser 2 (22), a red laser 3 (23), a green laser 1 (24), a green laser 2 (25), and a green laser 3 (26), and the output ends are connected to the welding gun 10 through transmission optical fibers 2 (211), 3 (221), 4 (231), 5 (241), 6 (251), and 7 (261), respectively.

[0052] The exhaust gas cleaning system is installed at the input end of the welding torch 10, and specifically includes air blowing device 1 51, air blowing device 2 52, air blowing device 3 53, air blowing device 4 54, air supply device 1 55, air supply device 2 56, air extraction device 1 57 and air extraction device 2 58.

[0053] The control system specifically includes a control system integration device 71. The control system integration device 71 is connected to the input terminals of the welding torch 10, the cleaning red laser 22, the cleaning red laser 21, the cleaning red laser 23, and the laser generating device 16 via data transmission line 711, output signal line 1 712, output signal line 2 713, output signal line 3 714, and output signal line 5 716, respectively. The output terminal of the control system integration device 71 is also connected to an output signal line 4 715. The output terminal of the output signal line 4 715 is connected to a welding wire supply device. The welding wire supply device is connected to the welding torch 10 via a welding wire feeding channel 94.

[0054] Specifically, the exhaust gas cleaning system is also equipped with galvanometer laser head 1 (41), galvanometer laser head 2 (42), and galvanometer laser head 3 (43), and the output ends of cleaning red laser 1 (21), cleaning red laser 2 (22), and cleaning red laser 3 (23) are respectively connected to galvanometer laser head 1 (41), galvanometer laser head 2 (42), and galvanometer laser head 3 (43), and the three form a 120-degree angle pointing towards the center of the focal welding wire for cleaning.

[0055] Specifically, the waste gas cleaning system is equipped with monitoring cameras 61, 62, and 63, which are angled at 120 degrees to the center of the welding wire for real-time monitoring.

[0056] Specifically, the welding wire supply device includes a clamping block 91, a welding wire spool 92, a rotating shaft 93, and a welding wire feeding channel 94. The welding wire spool 92 is mounted on the rotating shaft 93, which is located on the clamping block 91. The welding wire feeding channel 94 is used to transmit welding wire between the welding wire spool 92 and the welding torch 10.

[0057] Specifically, it also includes a cryogenic atmosphere system, which includes an argon cylinder 81, a compressed gas cylinder 82, a liquid nitrogen cylinder 83, and a temperature sensor 832. The temperature sensor 832 is installed inside the waste gas cleaning system to detect the internal temperature. The argon cylinder 81 is connected to the welding torch 10 through a pressure reducing valve and a mass flow controller via a gas supply pipe 1 811. The output end of the compressed gas cylinder 82 is connected to the first gas blowing device 51, the second gas blowing device 52, the third gas blowing device 53, and the fourth gas blowing device 54 via gas supply pipes 2 821 and 3 822, respectively. The liquid nitrogen cylinder 83 is connected to the inside of the waste gas cleaning system through gas supply pipe 4 831 to control its internal temperature.

[0058] Specifically, the exhaust gas cleaning system at one end of the welding torch 10 is equipped with two honeycomb-shaped pipes 13, which are connected to the first extraction device 57 and the second extraction device 58 respectively. This allows the negative pressure of the exhaust gas generated by the first extraction device 57 and the second extraction device 58 to be distributed on both sides of the welding wire. Below the bottom honeycomb-shaped pipe 13, there is a conical groove block 17 fixed on the inner wall of the welding torch 10. The conical groove block 17 guides the sinking debris and collects it inside the honeycomb-shaped pipe 13.

[0059] Specifically, another honeycomb-shaped pipe 13 is fitted with a secondary housing 15 on the outside, and the secondary housing 15 has holes for welding wire to pass through. The secondary housing 15 is equipped with a gas supply pipe 5 14, and the gas supply pipe 5 14 is connected to a compressed gas cylinder 82 for gas supply, which is used to form a separate reflux system for secondary cleaning. Example

[0060] like Figure 1 As shown, the present invention discloses a laser fusion device for ultrafast laser pretreatment of magnesium-lithium welding wire surface. The fiber laser fusion manufacturing system is used to generate a fiber laser beam. Part of the energy of the fiber laser beam acts on the welding wire to melt, and another part of the energy acts on the workpiece to achieve deep penetration welding of metal.

[0061] The red-green laser layered cleaning system is used to achieve real-time cleaning of welding wires. The generated laser beam acts on the surface of the welding wire inside the device to remove oxides from the surface. The red-green laser layered cleaning system includes a cleaning red laser 1 (21), a cleaning red laser 2 (22), a cleaning red laser 3 (23), a galvanometer laser head 1 (41), a galvanometer laser head 2 (42), and a galvanometer laser head 3 (43), which are arranged at a 120° angle towards the focal point of the welding wire. Figure 6 As shown, the internal structure of the galvanometer laser head and the optical path diagram can be seen. The laser cleaning process can achieve a layered and regional cleaning effect on the welding wire. The outermost layer is mainly loose and porous water vapor / CO2 reactants such as LiOH / Li2CO3, which may contain salts and oil. Green light can remove, carbonize, or remove contaminants from the outer loose film. Utilizing multiphoton absorption and defect activation, low-energy micro-abrasion is performed to "pre-crack" the material for subsequent stripping. The middle layer is mainly a mixed layer of Li2O and MgO with moderate density. The inner layer is mainly dense MgO, which is tightly bonded to the metal substrate and is the most "difficult" layer to remove. An impact stripping method is used, applying green light first and then red light, with green and red beams combined, to the middle and inner dense layers. Transient thermal stress gradients and nano-bursts can be generated at the interface weakened by green light, removing the entire film. The energy and number of cycles can be adjusted between 3:7 and 5:5 using a green:red energy ratio; the green-first-red sequence is particularly effective for dense MgO.

[0062] like Figure 2, Figure 5 and Figure 7 As shown, the air blowing device includes air blowing device 1 51 and air blowing device 3 53 located on the upper part of the cleaning device, air blowing device 2 52 and air blowing device 4 54 located on the lower part of the cleaning device, air supply device 1 55 and air supply device 2 56 located on the left side of the cleaning device, and air extraction device 1 57 and air extraction device 2 58 located on the right side of the cleaning device.

[0063] like Figure 3 As shown, the real-time monitoring system for the cleaning process includes three cameras: a first real-time monitoring camera 61, a second real-time monitoring camera 62, and a third real-time monitoring camera 63, all located inside the main cleaning unit. These three cameras are positioned at a 120° angle towards the center of the welding wire at the focus point.

[0064] The control system is used to coordinate the control monitoring and cleaning process. It includes a control system integration device 71 and data transmission lines 711 that acquire data from the real-time monitoring system of the cleaning process, output signal lines 712, 713, 714, 715, and 716 that send command data. It is the core of the system from data acquisition to command issuance.

[0065] The welding wire feeder is used to feed welding wire under the command of the control system. It includes a welding wire spool 92 mounted above a rotating shaft 93, which is mounted on a clamping block 91. The welding wire is automatically fed into the laser cleaning device through the welding wire feed channel 94 and then output to the welding gun head.

[0066] like Figure 7 As shown, the cryogenic atmosphere system includes a liquid nitrogen cylinder 83 and a temperature sensor 832 in the cleaning device. By setting a target temperature value, the temperature sensor 832 controls the liquid nitrogen cylinder 83 to precisely release nitrogen gas flow through a solenoid valve, so as to achieve a constant and controllable temperature inside the cleaning device.

[0067] The present invention discloses a laser fusion method for ultrafast laser pretreatment of magnesium-lithium welding wire surface, based on the aforementioned laser fusion device for ultrafast laser pretreatment of magnesium-lithium welding wire surface, comprising the following steps:

[0068] Step 1: Environmental and Protection and Cryogenic System Preparation. Start the blowing, exchanging, and evacuating systems to create a directional airflow, and check the dust collection and filtration differential pressure.

[0069] Step 2: Check for leaks in the gas path, cryogenic system, and argon system, then ventilate. Set the target temperature of the cavity according to the process specifications, and ensure the cryogenic system and temperature sensor 832 operate in a closed loop.

[0070] Step 3: Turn on the control, monitoring, and laser system. Load the material and welding wire parameter files into the host computer and set the recording and alarm thresholds. Monitor the camera and lighting for self-testing, and complete the geometric calibration and time synchronization of the calibration board.

[0071] Step 4: Perform optical path and focusing. Collimation, beam splitting, reflection, and galvanometer channel checks are performed on fiber lasers and ultrafast lasers under analog output. Focal length / spot position calibration is completed using the target provided by the manufacturer.

[0072] Step 5: Verify the geometric position of the wire feeder and welding head. Set the safety stroke and soft limit; verify the "light touch" positioning and zero return accuracy of the welding head under no-load conditions. Run the wire feeder without load and observe the consistency between the wire guide / pressure / feed wheel meshing and the encoder.

[0073] Step Six: Monitoring-Cleaning-Welding Linkage Drill. No-load linkage: The wire feed trajectory, cleaning galvanometer trajectory, and camera acquisition sequence are consistent; low-power / short-time testing on the sample confirms that the camera can correctly distinguish circumferential oxidation differences and drive the three-channel galvanometer for differentiated cleaning; dust is carried in and extracted by directional airflow.

[0074] Step 7: Formal Additive Manufacturing. First, establish stable protective gas and target temperature and humidity conditions; initiate arcing with low power and short passes, and monitor the synchronization of power / duty cycle / scanning trajectory and wire feed speed throughout the process, triggering interlock shutdown in case of abnormalities.

[0075] Therefore, the present invention adopts the above-mentioned laser melting wire device and method for ultrafast laser pretreatment of magnesium-lithium welding wire surface. Through the synchronous control of the real-time monitoring system of the cleaning process, the red-green laser layer cleaning system and the control system, and the output of the non-balance energy of the red-green laser layer cleaning device, the non-balance cleaning and layer removal of magnesium-lithium welding wire are realized, thereby solving the problems of easy oxidation and poor weldability of magnesium-lithium welding wire.

[0076] Example 2: Based on Example 1, the addition of a secondary shell 15, honeycomb perforated pipe 13, and air supply pipe 14 allows for an additional stage of fine cleaning during the cleaning process of blowing and then extracting air from the welding wire. This prevents the irregular flow of debris caused by blowing and extraction within the same space, which could lead to internal dust disorder and the possibility of small amounts of debris being carried out and used in welding, affecting the welding quality. The two-stage cleaning system enables an independent circulation system, preventing debris from entering during the external cleaning process while also performing a fine cleaning on the final welding wire, achieving a high-precision cleaning effect.

[0077] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A laser welding wire device for ultrafast laser pretreatment of magnesium-lithium welding wire surface, comprising a welding torch, a welding wire supply device, and a fiber laser head, characterized in that: Also includes: A fiber laser filament manufacturing system includes a fiber laser workpiece disposed at the bottom of a fiber laser head and a transmission fiber connected to the input end of the fiber laser head, wherein the fiber laser workpiece is connected to a laser generating device through the transmission fiber. The red-green laser layer cleaning system includes cleaning red laser 1, cleaning red laser 2, cleaning red laser 3, cleaning green laser 1, cleaning green laser 2, and cleaning green laser 3, and the output ends are connected to the welding gun through transmission optical fibers 2, 3, 4, 5, 6, and 7 respectively. The exhaust gas cleaning system is installed at the input end of the welding torch and includes an air blowing device 1, an air blowing device 2, an air blowing device 3, an air blowing device 4, an air supply device 1, an air supply device 2, an air extraction device 1, and an air extraction device 2. The control system includes a control system integration device. The control system integration device is connected to the input terminals of the welding torch, the cleaning red laser 2, the cleaning red laser 1, the cleaning red laser, and the laser generating equipment via data transmission line, output signal line 3, and output signal line 5, respectively. The output terminal of the control system integration device is also connected to an output signal line 4. The output terminal of the output signal line 4 is connected to a welding wire supply device. The welding wire supply device is connected to the welding torch via a welding wire feeding channel. The exhaust gas cleaning system is also equipped with three galvanometer laser heads: a first galvanometer laser head, a second galvanometer laser head, and a third galvanometer laser head. The output ends of the first, second, and third cleaning red lasers are respectively connected to the first, second, and third galvanometer laser heads. The three galvanometer laser heads form a 120-degree angle pointing towards the center of the focal welding wire for cleaning purposes. It also includes a cryogenic atmosphere system, comprising an argon cylinder, a compressed gas cylinder, a liquid nitrogen cylinder, and a temperature sensor. The temperature sensor is installed inside the waste gas cleaning system to detect the internal temperature. The argon cylinder is connected to the welding torch via a pressure reducing valve and a mass flow controller through a gas supply pipe. The output end of the compressed gas cylinder is connected to blowing device one, blowing device two, blowing device three, and blowing device four via gas supply pipe two and gas supply pipe three, respectively. The liquid nitrogen cylinder is connected to the inside of the waste gas cleaning system via gas supply pipe four to control its internal temperature.

2. The laser melting device for ultrafast laser pretreatment of magnesium-lithium welding wire surface according to claim 1, characterized in that: The exhaust gas cleaning system is also equipped with monitoring camera 1, monitoring camera 2 and monitoring camera 3, which are at a 120-degree angle to the center of the welding wire for real-time monitoring.

3. The laser melting device for ultrafast laser pretreatment of magnesium-lithium welding wire surface according to claim 1, characterized in that: The welding wire supply device includes a clamping block, a welding wire spool, a rotating shaft, and a welding wire feeding channel. The welding wire spool is mounted on the rotating shaft, which is located on the clamping block. The welding wire feeding channel is used to transmit welding wire between the welding wire spool and the welding torch.

4. The laser melting device for ultrafast laser pretreatment of magnesium-lithium welding wire surface according to claim 1, characterized in that: The exhaust gas cleaning system at one end of the welding torch is also equipped with two honeycomb-shaped pipes, which are connected to the first and second extraction devices respectively. This allows the negative pressure of the exhaust gas generated by the first and second extraction devices to be distributed on both sides of the welding wire. Below the bottom honeycomb-shaped pipe, there is a conical groove block fixed to the inner wall of the welding torch. The conical groove block guides the sinking debris and collects it inside the honeycomb-shaped pipe.

5. The laser melting device for ultrafast laser pretreatment of magnesium-lithium welding wire surface according to claim 4, characterized in that: Another honeycomb-shaped pipe is fitted with a secondary shell, and the secondary shell has an opening for the passage of welding wire. The secondary shell is equipped with a gas supply pipe five, and the gas supply pipe five is connected to a compressed gas cylinder for gas supply, which is used to form a separate reflux system for secondary cleaning.

6. A laser-fused wire method for ultrafast laser pretreatment of the surface of magnesium-lithium welding wire, wherein the method operates the apparatus described in claim 5, characterized in that: The specific steps are as follows: S1. Start blowing, exchanging and extracting air to form a directional airflow, and check the dust collection and filtration differential pressure; S2, Ventilation: Set the target temperature of the cavity according to the process specifications, and operate the low temperature and temperature sensor in a closed loop. S3. Turn on the control, monitoring and laser system. Load the material and welding wire parameter files into the host computer and set the recording and alarm thresholds. Monitor the camera and lighting self-test and complete the geometric calibration and time synchronization of the calibration board. S4. Perform optical path and focus checks. Under analog output, collimate, split, reflect, and check the galvanometer channel of fiber laser and ultrafast laser to complete the focal length / spot position verification. S5. Verify the geometric position of wire feeder and welding head, set the safe stroke and soft limit; verify the welding head light point positioning and zero return accuracy under no-load conditions; run the wire feeder without load and observe the meshing of the wire guide / pressure / feeding wheel and the consistency of the encoder pulse. S6. Monitoring system—red—green laser layer cleaning system—laser welding linkage exercise, no-load linkage: wire feeding trajectory, cleaning galvanometer trajectory and camera acquisition timing are consistent; Low-power / short-time testing on the sample confirmed that the camera could correctly distinguish circumferential oxidation differences and drive the three-way galvanometer differential cleaning; dust was carried into the exhaust by directional airflow. S7. Formal additive manufacturing: First, establish stable protective gas and target temperature and humidity conditions; initiate arcing with low power and short passes; monitor the synchronization of power / duty cycle / scanning trajectory and wire feed speed throughout the process; trigger interlock to stop in case of abnormality.

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