A laser-electrolysis hybrid machining device and method based on magnetohydrodynamics

Abstract

The application relates to the technical field of laser-electrolysis combined machining, in particular to a laser-electrolysis combined machining device and method based on magnetohydrodynamics, which comprises a laser module, a moving platform and a jet-electrolysis machining module, the jet-electrolysis machining module comprises a cathode nozzle, an anode workpiece holder, an electrolytic tank, an electromagnet, a second adapter plate, an optical connecting rod, an anode workpiece, a liquid circulating pump, a filter, a 24V switching power supply, an electrolyte storage tank and a pulse power supply. Two electromagnets are arranged along the jet axis and the laser arrangement connection direction, the fluid flow characteristics of the solution in different directions are changed by changing the electromagnet position and the power-on parameters, the controllable adjustment of the liquid film thickness at the two ends of the jet axis is realized, the anode surface profile uniformity in the non-coaxial laser-electrolysis combined machining is improved, and the size and shape precision of the machined parts are improved.

Description

Technical Field

[0001] This invention relates to the field of laser electrolytic composite processing technology, and in particular to a laser electrolytic composite processing apparatus and method based on magnetohydrodynamics. Background Technology

[0002] Jet electrochemical machining is a variant of electrochemical machining, possessing the non-thermal and non-contact characteristics of electrochemical machining. The difference between it and traditional electrochemical machining lies in the mode of electrolyte delivery to the surface. Under sufficient pressure, a free jet is emitted from the nozzle and impacts the workpiece surface to form a radial thin film region. The continuously flowing electrolyte can maintain the stability of the machining process and continuously remove electrolytic products and Joule heat from the machining gap. At the same time, the highly localized process control is the most important advantage of jet electrochemical machining. This technology is often used for surface modification to achieve the regulation of material surface functions.

[0003] However, low material removal rates limit the further application of jet electrochemical machining. Existing research indicates that the high spatiotemporal controllability of laser energy and its non-contact action mechanism make it highly attractive for enhancing the capabilities of jet electrochemical machining. Introducing laser energy can weaken the passivation layer on the material surface and promote the uniform dissolution process. Simultaneously, the increased current density in the processing area by the laser also helps to improve the solution conductivity and enhance the material removal process.

[0004] To achieve the aforementioned advantages, the introduction and coupling methods of laser and electrochemical energy need to be considered. Currently, coaxial and non-coaxial processing methods are commonly used. However, coaxial laser-electrolytic composite processing devices have complexities in practical applications, while non-coaxial laser-electrolytic jet composite processing needs to address the problem of uneven current density distribution on the anode surface. Due to the inclined arrangement of the cathode nozzle, the distance between the equipotential surface perpendicular to the jet axis and the anode workpiece surface changes. In addition, there is a significant difference in the thickness of the electrolyte film in the forward flow direction and the return flow direction of the free jet in contact with the workpiece. The reduction in distance means lower solution resistance, and the thinner electrolyte film thickness is beneficial to enhancing the current density confinement effect. Both of these factors jointly affect the current density distribution on the anode surface, resulting in a non-axisymmetric anode profile. Therefore, it is urgent to apply a technology to control the uniformity of the current density distribution on the anode surface during non-coaxial laser-electrolytic composite processing. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing technologies and propose a laser electrolytic composite processing device and method based on magnetohydrodynamics. By installing two electromagnets along the direction of the jet axis and the laser arrangement line, the fluid flow characteristics of the solution in different directions can be changed, and the thickness of the liquid film at both ends of the jet axis can be controlled and adjusted, thereby improving the uniformity of the anode surface profile in non-coaxial laser electrolytic composite processing.

[0006] To achieve the above objectives, the present invention adopts the following specific technical solution:

[0007] The present invention provides a laser-electrolysis composite processing device based on magnetohydrodynamics, comprising a laser module, a moving platform, and a jet electrolysis processing module;

[0008] The laser module includes a femtosecond laser, a reflector, and a focusing lens. The reflector and focusing lens are located at the front end of the laser emission position of the femtosecond laser. The reflector and focusing lens are connected to the first adapter plate fixed on the surface of the marble platform on the optical vibration isolation platform through a connecting rod, a connecting rod bracket, and a pressure block. The reflector and focusing lens are used to introduce laser energy into the electrolytic cell of the jet electrolytic processing module.

[0009] The mobile platform includes an X and Y directional mobile platform and a Z directional shear lifting platform, and the mobile platform is fixed on the marble platform;

[0010] The jet electrolytic machining module includes a cathode nozzle, an anode workpiece holder, an electrolytic cell, an electromagnet, a second adapter plate, an optical connector, an anode workpiece, a liquid circulation pump, a filter, a 24V switching power supply, an electrolyte storage tank, and a pulse power supply.

[0011] The electrolytic cell is connected to the mobile platform. An electrolyte outlet connected to the electrolyte storage tank is located below the electrolytic cell. The cathode nozzle is positioned at a 45° angle within the electrolytic cell. The cathode nozzle is connected via pipelines to a liquid circulation pump, a filter, and the electrolyte storage tank pre-filled with electrolyte. The liquid circulation pump is connected to a 24V switching power supply to circulate and filter the electrolyte in the electrolytic cell. The anode workpiece is fixed using an anode workpiece holder. The cathode nozzle and the anode workpiece holder are connected to the negative and positive terminals of the pulse power supply, respectively, to make the anode workpiece conductive. Two electromagnets are located on either side of the cathode nozzle. The anode workpiece holder and the electromagnets are fixedly connected via a second adapter plate, which is connected to the electrolytic cell via an optical connector.

[0012] Specifically, the femtosecond laser is placed on top of an optical breadboard and elevated on an optical vibration isolation platform by a support column at the bottom; the laser module also includes a laser shield, which is set behind the first reflector through which the laser passes to block the transmitted laser.

[0013] Specifically, the cathode nozzle is connected in sequence to the liquid circulation pump, filter, and electrolyte storage tank via PU tubes. The filter is equipped with a 1μm filter element for filtering the electrolyte. A liquid shield is installed above the electrolytic cell to prevent liquid splashing. The cathode nozzle is installed inside the electrolytic cell through the reserved holes in the liquid shield. The jet electrolysis processing module also includes a high-speed camera. The electrolytic cell is made of transparent acrylic material and is used to observe the reaction inside the electrolytic cell.

[0014] Specifically, the electrolytic cell is connected to the X and Y moving platform, and the X and Y moving platform is connected to the Z shear lifting platform; the cathode nozzle is set at a 45° angle at a distance of 1-2 mm from the surface of the anode workpiece to ensure that the extended line of the cathode nozzle jet axis is connected to the laser action center.

[0015] This invention also provides a laser-electrolytic composite processing method based on magnetohydrodynamics, comprising the following steps:

[0016] S1. Grind and polish the surface of the anode workpiece, ultrasonically clean and dry it. Use the anode workpiece holder to fix the anode workpiece. Turn on the 24V switching power supply connected to the liquid circulation pump. The liquid circulation pump draws electrolyte from the electrolyte storage tank and continuously delivers it to the surface of the anode workpiece through the cathode nozzle.

[0017] S2. Turn on the femtosecond laser, adjust the X and Y axis moving platforms and the Z axis shear lifting platform so that the laser irradiates the processing area of ​​the anode workpiece in a defocused form, adjust the tilt angle of the cathode nozzle and fix it at 45°, use a high-speed camera to observe the processing area and keep the processing gap at 1-2mm, connect the extension line of the jet axis with the position of the laser action center, and keep the pulse power supply in the off state.

[0018] S3. Keep the laser preheating the processing area, set the pulse power parameters, and record the thickness of the liquid film on both sides of the jet axis after a stable liquid film is formed on the surface of the anode workpiece.

[0019] S4. Power the two electromagnets with 12V and 24V DC power supplies respectively, turn on the pulse power supply, use a Tesla meter to measure the magnetic field strength on both sides of the cathode nozzle and record the data, and observe and record the liquid film thickness at this time through a high-speed camera.

[0020] S5. Measure the cross-sectional profile shape of the anode workpiece after processing, evaluate the profile uniformity of the anode workpiece by the difference between the angles between the two edges of the cross-sectional profile and the horizontal plane, and record the data.

[0021] S6. Change the voltage applied by the two electromagnets and repeat the experiment to find the liquid film thickness, electromagnet working voltage and magnetic field strength corresponding to the uniform outline of the anode workpiece.

[0022] S7. Turn off the femtosecond laser, pulse power supply and liquid circulation pump, remove the anode workpiece to complete the processing, and clean the electrolytic cell.

[0023] Preferably, in step S1, the outlet flow rate of the cathode nozzle is maintained at 10 m / s by adjusting the liquid flow valve and the volumetric flow rate calculation method; in step S2, the pulse frequency of the femtosecond laser is set to 5 kHz and the laser power is 0.05 W; in step S3, the voltage of the pulse power supply is set to 8 V; in step S4, both electromagnets are made of enameled copper with a diameter of 0.8 mm and 200 turns, and the distance between the two electromagnets and the left and right sides of the anode workpiece is set to 2 mm.

[0024] The present invention can achieve the following technical effects:

[0025] 1. This invention improves the flexibility and applicability of non-coaxial laser electrolytic composite processing technology, enhances the process capability of non-coaxial laser electrolytic composite processing technology, and meets diverse production needs;

[0026] 2. By installing two electromagnets along the direction connecting the jet axis and the laser arrangement, and ensuring a stable liquid film is formed on the surface of the anode workpiece, energizing the electromagnets at both ends of the workpiece causes changes in the flow and mass transfer characteristics of the fluid due to the Lorentz force acting on the charged particles in the electrolyte solution. By changing the position of the electromagnets and setting different energizing parameters, different magnitudes and directions of Lorentz forces are generated on the electrolyte solution in different directions, thereby changing the fluid flow characteristics of the solution in different directions. Ultimately, the thickness of the liquid film at both ends of the jet axis can be controllably adjusted. This method improves the uniformity of the anode surface contour in non-coaxial laser-electrolytic composite machining, improves the dimensional and shape accuracy of the machined parts, and is of great significance for manufacturing high-precision complex structures on the surface of difficult-to-machine materials.

[0027] 3. Applying magnetohydrodynamics (MHD) technology to the regulation of current density on the anode surface expands the application scenarios of this technology. The MHD effect can promote the mass transfer of ions on the anode surface and the desorption of bubbles. At the same time, the irradiation effect of laser also helps to stabilize the current density distribution on the anode surface and promote the uniform dissolution of materials, ultimately achieving a smooth, flat, and uniform anode surface profile. Furthermore, the magnetic field distribution can be precisely designed and the MHD characteristics can be controlled to achieve the controllable regulation of fluid movement within the micro-reaction zone. This method helps to manufacture microstructured surfaces with specific functions. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the structure of a laser-electrolytic composite processing device based on magnetohydrodynamics according to an embodiment of the present invention;

[0029] Figure 2 This is a schematic diagram of the internal component structure of an electrolytic cell according to an embodiment of the present invention;

[0030] Figure 3This is a schematic diagram of the control of electrolyte film thickness by magnetohydrodynamic effect according to an embodiment of the present invention.

[0031] The reference numerals in the figures include:

[0032] 1. Femtosecond laser; 2. Optical breadboard; 3. Support column; 4. Optical vibration isolation platform; 5. Laser protective cover; 6. Optical path assembly; 7. First adapter plate; 8. Connecting rod bracket; 9. Pressure block; 10. Liquid shield; 11. Marble platform; 12. Cathode nozzle; 13. Anode workpiece holder; 14. Electrolytic cell; 15. Second adapter plate; 16. Optical connecting rod; 17. Anode workpiece; 18. X and Y axis moving platform; 19. Z axis shear lifting platform; 20. Liquid circulation pump; 21. Filter; 22. 24V switching power supply; 23. Electrolyte pipeline; 24. Electrolyte storage tank; 25. High-speed camera; 26. Pulse power supply; 27. Detailed Implementation

[0033] In the following description, embodiments of the invention will be described with reference to the accompanying drawings. In the description below, the same modules are denoted by the same reference numerals. Where the same reference numerals are used, their names and functions are also the same. Therefore, their detailed description will not be repeated.

[0034] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not constitute a limitation thereof.

[0035] This invention provides a laser-electrolytic composite processing device based on magnetohydrodynamics, the structure of which is as follows: Figure 1 As shown, the femtosecond laser 1 is placed above the optical breadboard 2, elevated by the supporting columns 3 at the bottom, and mounted on the optical vibration isolation platform 4. An optical path assembly 6, consisting of a reflector and a focusing lens, is installed at the front end of the laser emission position of the femtosecond laser 1. A laser shield 5 is installed behind the first reflector through which the laser passes to block the transmitted laser. The reflector and focusing lens are connected to the first adapter plate 7 on the marble platform 11 via connecting rods, connecting rod brackets 8, and pressure blocks 9. The optical path assembly 6 can introduce laser energy into the reaction zone within the electrolytic cell 14.

[0036] An electrolyte outlet is provided on the lower side of the electrolytic cell 14 and is connected to the electrolyte storage tank 25 through the electrolyte pipe 24. The electrolytic cell 14 is connected to the X and Y direction moving platform 19 below. The X and Y direction moving platform 19 is connected to the Z direction shear lifting platform 20. The entire moving platform, including the X and Y direction moving platform 19 and the Z direction shear lifting platform 20, is fixed on the marble platform 11.

[0037] A liquid shield 10 is placed above the electrolytic cell 14. The cathode nozzle 12 can pass through the pre-drilled hole at the center of the liquid shield 10. The cathode nozzle 12 is connected to the liquid circulation pump 21, the filter 22 with a 1μm filter element and the electrolyte storage tank 25 in sequence through the electrolyte pipe 24. The liquid circulation pump 21 is powered by a 24V switching power supply 23. The entire composite processing device is fixedly installed on the optical vibration isolation platform 4. The electrolytic cell 14 is made of transparent acrylic material. The high-speed camera 26 is used to observe the reaction zone inside the electrolytic cell 14.

[0038] Figure 2 The internal component structure of the electrolytic cell is shown, such as... Figure 2 As shown, the electrolytic cell 14 includes a cathode nozzle 12, an anode workpiece holder 13, an electromagnet 15, a second adapter plate 16, and optical connectors 17. The cathode nozzle 12 is placed at a 45° angle and fixed at a position 1-2 mm away from the surface of the anode workpiece 18 by a universal clamp. It is necessary to ensure that the extended line of the jet axis of the cathode nozzle 12 is connected to the laser action center. The anode workpiece 18 is fixed by the anode workpiece holder 13. The cathode nozzle 12 and the anode workpiece 18 are connected to the negative and positive terminals of the pulse power supply 27, respectively. Two electromagnets 15 are arranged on the left and right sides of the cathode nozzle 12. The anode workpiece holder 13 and the electromagnets 15 are fixedly connected by the second adapter plate 16 at the bottom. The second adapter plate 16 is made of polytetrafluoroethylene and is connected to the electrolytic cell 14 by four optical connectors 17.

[0039] Figure 3 This paper demonstrates how magnetohydrodynamic (MHD) effects can be used to control the thickness of the electrolyte film. In non-coaxial laser-electrolytic jet composite processing, due to the inclined arrangement of the cathode nozzle 12, the current density on the surface of the anode workpiece 18 exhibits a significant non-axisymmetric distribution under the combined influence of the distance between the equipotential surface of the jet axis and the anode workpiece 18, and the thickness of the liquid film. The current density is more concentrated in the direction of the acute angle between the cathode nozzle 12 and the horizontal plane, leading to non-uniform anode dissolution. Therefore, it is proposed to use the magnetic field-induced MHD effect to change the liquid film thickness in the free jet return direction and the forward flow direction, thereby controlling the current density distribution on the surface of the anode 18. After the cathode nozzle 12 forms a stable liquid film on the surface of the anode workpiece 18, the pulse power supply 27 is turned on, and the electromagnet 15 is energized. Different magnetic field intensities are applied to both sides of the cathode nozzle 12. The laser plays a role in enhancing the reaction kinetics process throughout the process, ultimately achieving the generation of liquid films with different thicknesses in the forward and return directions. Through multiple experiments, the optimal liquid film thickness and process parameters of the electromagnet 15 corresponding to the uniformity of the anode workpiece 18 contour can be found.

[0040] This invention involves installing two electromagnets along the jet axis and the line connecting the laser beam. With a stable liquid film formed on the anode workpiece surface, energizing the electromagnets at both ends of the workpiece alters the flow and mass transfer characteristics of the fluid due to the Lorentz force acting on the charged particles in the electrolyte solution. By changing the electromagnet positions and setting different energizing parameters, different magnitudes and directions of Lorentz forces are generated on the electrolyte solution in different directions, thereby changing the fluid flow characteristics in different directions and ultimately achieving controllable adjustment of the liquid film thickness at both ends of the jet axis. Furthermore, the magnetohydrodynamic effect promotes ion mass transfer and bubble desorption on the anode surface, while laser irradiation helps stabilize the current density distribution on the anode surface and promotes uniform material dissolution, ultimately achieving a smooth, flat, and highly uniform anode surface profile.

[0041] This invention also provides a laser-electrolytic composite processing method based on magnetohydrodynamics, which mainly includes the following steps:

[0042] Step 1: Grind and polish the surface of the anode workpiece 18, ultrasonically clean and dry it, fix the anode workpiece 18 with the anode workpiece holder 13, turn on the 24V switching power supply 23 of the liquid circulation pump 21, adjust the liquid flow valve and keep the outlet flow velocity of the cathode nozzle 12 at about 10m / s by calculating the volume flow rate.

[0043] Step 2: Open the control interface of the femtosecond laser 1, set the pulse frequency to 5kHz and the laser power to 0.05W, turn on the laser start button, control the X and Y axis moving platform 19 to make the laser spot just aligned with the upper surface of the anode workpiece 18, at this time raise the Z axis shear lifting platform 20 to 2mm so that the laser irradiates the processing area of ​​the anode workpiece 18 in a defocused form, adjust the tilt angle of the cathode nozzle 12 and fix it at 45°, use the high-speed camera 26 to observe the processing area and keep the processing gap at 1~2mm, and connect the extension line of the jet axis with the position of the laser action center, and keep the pulse power supply 27 in the off state.

[0044] Step 3: Preheat the processing area with laser, set the process parameters of pulse power supply 27, set the voltage to 8V, and record the thickness of the liquid film on both sides of the jet axis after a stable liquid film is formed on the surface of the anode workpiece 18.

[0045] Step 4: Both electromagnets 15 are made of enameled copper with a diameter of 0.8 mm and 200 turns. The two electromagnets 15 are powered by 12V and 24V power supplies respectively. The distance between the two electromagnets 15 and the surface of the anode workpiece 18 is set to 2 mm. The pulse power supply 27 and the DC power supply for controlling the operation of the electromagnets 15 are turned on. The magnetic field strength on both sides of the cathode nozzle 12 is measured with a Tesla meter and the data is recorded. The liquid film thickness at this time is observed and recorded by a high-speed camera 26.

[0046] Step 5: Measure the cross-sectional profile shape of the processed anode workpiece 18 using an optical microscope. Evaluate the profile uniformity of the anode workpiece 18 by the difference between the angles between the two edges of the cross-sectional profile and the horizontal plane, and record the data.

[0047] Step 6: Change the voltage applied across electromagnet 15 and repeat the above experimental process. Through multiple experiments, find the liquid film thickness, electromagnet 15 working voltage, and magnetic field strength corresponding to the best uniformity of the anode workpiece 18 contour.

[0048] Step 7: Turn off the femtosecond laser 1, pulse power supply 27 and liquid circulation pump 21, remove the anode workpiece 18 to complete the processing, rinse the electrolytic cell 14 with deionized water and wipe it with a lint-free cloth.

[0049] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0050] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

[0051] The specific embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made in accordance with the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A laser-electrolytic composite processing method based on magnetohydrodynamics, characterized in that, The processing equipment includes a laser module, a moving platform, and a jet electrolysis processing module; The laser module includes a femtosecond laser (1), a reflector and a focusing lens. The reflector and focusing lens are located at the front end of the laser emission position of the femtosecond laser (1). The reflector and focusing lens are connected to the first adapter plate (7) fixed on the surface of the marble platform (11) on the optical vibration isolation platform (4) through a connecting rod, a connecting rod bracket (8) and a pressure block (9). The reflector and focusing lens are used to introduce laser energy into the electrolytic cell (14) of the jet electrolytic processing module. The mobile platform includes an X and Y directional mobile platform (19) and a Z directional shear lifting platform (20), and the mobile platform is fixed on the marble platform (11); The jet electrolytic machining module includes a cathode nozzle (12), an anode workpiece holder (13), an electrolytic cell (14), an electromagnet (15), a second adapter plate (16), an optical connector (17), an anode workpiece (18), a liquid circulation pump (21), a filter (22), a 24 V switching power supply (23), an electrolyte storage tank (25), and a pulse power supply (27). The electrolytic cell (14) is connected to the mobile platform. An electrolyte outlet connected to the electrolyte storage tank (25) is located below the electrolytic cell (14). The cathode nozzle (12) is inclined at 45° within the electrolytic cell (14). The cathode nozzle (12) is connected sequentially to the liquid circulation pump (21), the filter (22), and the electrolyte storage tank (25) pre-filled with electrolyte via pipelines. The liquid circulation pump (21) is connected to the mobile platform (24). The V switching power supply (23) is connected to circulate and filter the electrolyte in the electrolytic cell (14); the anode workpiece (18) is fixed by the anode workpiece holder (13), the cathode nozzle (12) and the anode workpiece holder (13) are respectively connected to the negative and positive terminals of the pulse power supply (27) to make the anode workpiece (18) conductive; two electromagnets (15) are provided on both sides of the cathode nozzle (12), the anode workpiece holder (13) and the electromagnets (15) are fixedly connected by the second adapter plate (16), and the second adapter plate (16) is connected to the electrolytic cell (14) by an optical connector (17); The processing method includes the following steps: S1. Grind, polish, ultrasonically clean and dry the surface of the anode workpiece (18). Fix the anode workpiece (18) with the anode workpiece holder (13). Turn on the 24 V switching power supply (23) connected to the liquid circulation pump (21). The liquid circulation pump (21) draws electrolyte from the electrolyte storage tank (25) and continuously delivers it to the surface of the anode workpiece (18) through the cathode nozzle (12). S2. Turn on the femtosecond laser (1), adjust the X and Y direction moving platform (19) and the Z direction shear lifting platform (20) so that the laser irradiates the processing area of ​​the anode workpiece (18) in a defocused form, adjust the tilt angle of the cathode nozzle (12) and fix it at 45°, use the high-speed camera (26) to observe the processing area, keep the processing gap between the cathode nozzle (12) and the anode workpiece (18) at 1-2 mm, connect the extension line of the jet axis with the position of the laser action center, and keep the pulse power supply (27) in the off state. S3. Keep the laser preheating the processing area, set the pulse power supply (27) parameters, and record the thickness of the liquid film on both sides of the jet axis after a stable liquid film is formed on the surface of the anode workpiece (18). S4. Power the two electromagnets (15) with 12V and 24V DC power supplies respectively, turn on the pulse power supply (27), use a Tesla meter to measure the magnetic field strength on both sides of the cathode nozzle (12) and record the data, and observe and record the liquid film thickness at this time through a high-speed camera (26). S5. Measure the cross-sectional profile shape of the anode workpiece (18) after processing, and evaluate the profile uniformity of the anode workpiece (18) by the difference between the two edges of the cross-sectional profile and the horizontal plane. S6. Repeat the experiment by changing the voltage applied by the two electromagnets (15) to obtain the liquid film thickness, working voltage of the electromagnets (15) and magnetic field strength when the contour of the anode workpiece (18) is uniform. S7. Turn off the femtosecond laser (1), pulse power supply (27) and liquid circulation pump (21), remove the anode workpiece (18) to complete the processing, and clean the electrolytic cell (14).

2. The laser-electrolytic composite processing method based on magnetohydrodynamics according to claim 1, characterized in that, The femtosecond laser (1) is placed above the optical breadboard (2) and elevated on the optical vibration isolation platform (4) by the support column (3) at the bottom; the laser module also includes a laser shield (5), which is set behind the first reflector through which the laser passes, and is used to block the transmitted laser.

3. The laser-electrolytic composite processing method based on magnetohydrodynamics according to claim 1, characterized in that, The cathode nozzle (12) is connected in sequence to the liquid circulation pump (21), the filter (22) and the electrolyte storage tank (25) via PU tubes. The filter (22) is equipped with a 1μm filter element for filtering the electrolyte. A liquid shield (10) is provided above the electrolytic cell (14) to prevent liquid splashing. The cathode nozzle (12) is installed inside the electrolytic cell (14) through the reserved hole of the liquid shield (10). The electrolytic cell (14) is made of transparent acrylic material. The jet electrolysis processing module also includes a high-speed camera (26) for observing the reaction in the electrolytic cell (14).

4. The laser-electrolytic composite processing method based on magnetohydrodynamics according to claim 1, characterized in that, The electrolytic cell (14) is connected to the X and Y moving platform (19), and the X and Y moving platform (19) is connected to the Z shear lifting platform (20). The cathode nozzle (12) is set at a 45° angle at a distance of 1-2 mm from the surface of the anode workpiece (18) to ensure that the extension line of the jet axis of the cathode nozzle (12) is connected to the laser action center.

5. The laser-electrolytic composite processing method based on magnetohydrodynamics according to claim 4, characterized in that, In step S1, the outlet velocity of the cathode nozzle (12) is maintained at 10 m / s by adjusting the liquid flow valve and the volume flow rate calculation method; In step S2, the pulse frequency of the femtosecond laser (1) is set to 5kHz and the laser power is 0.05W; In step S3, the voltage of the pulse power supply (27) is set to 8V; In step S4, both electromagnets (15) are made of enameled copper with a diameter of 0.8 mm and 200 turns. The distance between the two electromagnets (15) and the left and right sides of the anode workpiece (18) is set to 2 mm.

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