Autonomous and Controllable Deformation Electrochemical Machining Method and Device for Shape Memory Alloy Electrodes

Abstract

The present invention relates to a method and device for electrolytic machining with self - controllable deformation of a shape memory alloy electrode, belonging to the technical field of electrolytic machining. This method uses a shape memory alloy as the electrode material and the initial part profile line as the electrode shape. Through heat treatment, the electrode corresponds to different part profile line shapes at different temperatures. During electrolytic machining, the electrode is connected to a floating fixture, and the temperature of the electrolyte is regulated by the equipment to cause corresponding deformation at different positions. After the machining is completed, using the shape memory effect of the material, the electrode is heated to restore its shape. This method can not only achieve the machining of variable cross - sections but also reuse the electrode.

Description

Technical Field

[0001] The present invention relates to a method and device for electrolytic machining of self - controllable deformation of a shape memory alloy electrode, belonging to the technical field of electrolytic machining. Background Art

[0002] Aero - engines are one of the most complex industrial products and are known as the "pearl on the crown of industrial manufacturing". As the heart of an aircraft, their manufacturing level reflects a country's scientific and technological level and industrial level to a certain extent. With the continuous improvement of aircraft performance, the performance requirements for aero - engines are getting higher and higher. The emergence of the blisk reduces the number and weight of parts, avoids the overflow pressure loss of the tenon and mortise connection, improves the aerodynamic performance, simplifies the structure of the aero - engine, enhances the reliability and increases the thrust - to - weight ratio. After adding a full - circle shroud at the blade edge of the closed - type blisk, the flutter of the blade can be effectively suppressed, and the overall strength and stiffness of the blisk are improved. Abroad, the 4th - generation combat aero - engines represented by F119, F120, EJ200, etc. have generally adopted the blisk structure. After the engine of Rolls - Royce in the UK adopted the blisk structure, its weight was reduced by 50% compared with the traditional split structure of blades and disks; after the lift fan of the US Joint Strike Fighter JSF adopted the blisk structure, 30% of the cooling air was reduced, the service life increased by 100%, and the weight was reduced by 25% - 30%.

[0003] Electrolytic machining is a machining method for removing materials based on the principle of electrochemical anodic dissolution. In electrolytic machining, the hardness of the tool material can be lower than that of the machined part, so it is often used to machine difficult - to - cut materials such as high - strength, high - hardness, and high - temperature - resistant materials; at the same time, during the machining process, the electrolytic machining tool and the workpiece always maintain a machining gap, and there is no cutting force during machining, so it is suitable for machining complex - shaped parts such as precision, thin - wall, and easily - deformed parts. Due to the above characteristics of electrolytic machining, it has been widely used in the aerospace field and has become one of the main machining processes for machining aero - engine components.

[0004] In the patent "A Ring - shaped Electrode and Process Method for Electrolytic Grooving of a Blisk" (Application No. 201210367002.5, applicant Shenyang Liming Aero - Engine (Group) Co., Ltd., inventors Zhu Hainan, Yang Jianshi, Yu Bing, Li Wei), through the method of trepanning electrolytic machining, efficient machining of wide - chord and large - twist - angle blade - type channels of the blisk is realized.

[0005] In the patent "Method for Electrolytic Machining of Inter - blade Flow Channels of a Multi - electrode Spiral Feed Integral Impeller" (Application No. 200910025834.7, applicant Nanjing University of Aeronautics and Astronautics, inventors Zhu Di, Xu Qing, Xu Zhengyang), through the multi - dimensional interpolation movement between the tool cathode and the workpiece anode, a cascade channel is machined using a tubular electrode with a simple shape.

[0006] In the patent "A Non-uniform Double Rotation Electrochemical Machining Method for Integral Bladed Disk with Variable-width Machining Edges on the Cathode" (Application No. 201910756930.2, Applicant: Nanjing University of Aeronautics and Astronautics, Inventors: Xu Zhengyang, Wang Jing, Zhu Di), the machining edges of the cathode are designed as variable-width machining edges, which are driven to rotate radially in one direction with variable speed along the simulation trajectory; the blank is driven to rotate with variable direction and speed in coordination with the cathode according to the parameters optimized by simulation, so as to form a cascade channel on the blank and improve the uniformity of the machining allowance distribution.

[0007] In the patent "A Precision Electrochemical Machining Method for Variable-section Blades" (Application No. 201910818869.X, Applicant: AECC Aero Engine Corporation Limited, Inventors: Wang Fuping, Chen Wenliang, Lei Xiaojing, Hu Sijia, Li Yuan, Ren Jinggang, Yang Bo, Huang Chuhuang), the stabilization of the precision electrochemical machining process of the variable-section blade profile is realized, and the deficiencies of the existing integral bladed disk blade profile CNC milling machining with long cycle, low machining efficiency and high production cost are overcome.

[0008] In the patent "Double-blade Nesting Electrochemical Machining Device and Its Machining Method" (Application No. 202010425084.9, Applicant: Nanjing University of Aeronautics and Astronautics, Inventors: Zhu Dong, Zhang Xiaobo, Lin Jiahao), for the integral component with large and small blades, an integral tool cathode with two characteristics is designed, and the tool cathode is fed axially to realize the rapid nesting machining of the double blades.

[0009] In the patent "Nesting Electrochemical Machining Fixture and Method for Blade Trailing Edge Non-dissolving Diffuser" (Application No. 201910195765.8, Applicant: Nanjing University of Aeronautics and Astronautics, Inventors: Zhu Dong, Lin Jiahao, Hu Xingyan, Yue Chen, He Weifeng, Song Zhangyang, Chen Kaiqi, Li Han, Mao Yanqin), the problems of excessive fixture pressure and easy leakage of electrolyte during the nesting electrochemical machining of the diffuser are solved, which is beneficial to improving the flow field stability and machining quality.

[0010] In the patent "Electrochemical Machining Method for Aero-engine Thin-walled Casing" (Application No. 201410547093.X, Applicant: Nanjing University of Aeronautics and Astronautics, Inventors: Zhu Di, Zhu Zengwei, Wang Hongrui, Wang Dengyong), the workpiece anode rotates by itself, and the tool cathode feeds towards the anode while moving circumferentially. During the whole machining process, there is no need to replace the electrode, and the concave and convex structures on the surface of the thin-walled rotary parts are machined into shape at one time through the rolling sleeve electrochemical action of the cathode window.

[0011] In the patent "A Machine Tool Rotary Unit and a High-precision Rotary Printing Electrochemical Machining Machine Tool for Casing Parts" (Application No. 201810339512.9, Applicant: Nanjing University of Aeronautics and Astronautics, Inventors: Wang Dengyong, Zhu Di, He Bin, Zhu Zengwei, Li Tianyu, Fang Zhongdong), a new type of electrochemical machining machine tool is designed, with improved transmission accuracy and large allowable machining current, which gives full play to the advantages of high-efficiency electrochemical machining and expands the application range of rotary printing electrochemical machining.

[0012] In the patent "Electrochemical machining device for shallow cavity structure on surface of thin-wall casing and its electrochemical machining method" (Application No. 202010849493.1, Applicant: Yangzhou University, Inventors: Ge Yongcheng, Chen Wangwang, Zhu Yongwei, Dai Min), the cathode tool can be replaced with a corresponding cathode tool according to different machining cavities to meet the machining requirements of complex shallow cavity structures in different structural forms.

[0013] In electrochemical machining, the tool electrode needs to have characteristics such as good corrosion resistance and good electrical conductivity. At the same time, electrochemical machining belongs to copy machining, and the shape accuracy of the tool electrode determines the shape accuracy of the machined workpiece. For parts with complex surfaces such as blades and blisks, the blade surfaces of the integral blisk are distorted and complex, which is an irregular spatial geometric surface; the blades are extremely thin and easy to deform, with a thickness generally only a few millimeters; the curvature of the inlet and outlet edges of the blades is large and changes violently; the blade channels between the blades are narrow and long, usually dozens of millimeters deep, and the narrowest part is only a few millimeters. When machining such parts, the design of the tool electrode is often difficult and needs to take into account the overall distorted surface of the blade, which also additionally increases the time cost of machining and manufacturing the tool electrode.

[0014] Shape memory alloy refers to a type of alloy that, after being plastically deformed and fixed into another shape at low temperature with a certain initial shape, can return to the initial shape by heating above a certain critical temperature. Due to its shape memory effect and good elasticity, related products of shape memory alloys have also penetrated into various fields such as aerospace, machinery, electronics, and medicine, and achieved good results.

[0015] In the patent "Active control device for tip clearance of aeroengine based on shape memory alloy wire" (Application No. 201711348615.3, Applicant: Beihang University, Inventors: Pan Qiang, Liu Wendong, He Tian, Shan Yingchun), the memory alloy wire and the elastic plate are used in cooperation to deform and change the working state, and with other adjustable mechanisms, the working state transition of the variable cycle engine can be completed, which has the advantages of small structural weight, small occupied space, convenient control, and reliable movement.

[0016] In the patent "Scaled integral deformable afterbody ejector in a variable cycle engine" (Application No. 201910723502.X, Applicant: Beihang University, Inventors: Hu Dianyin, Wang Rongqiao, Hu Shuhao, Mao Jianxing, Liu Qian), by utilizing the shape memory effect characteristics of the temperature-controlled shape memory alloy, the pre-stretched shape memory alloy wire is connected to the tip clearance actuator of the aeroengine, and a suitable current is used to heat it to generate a recovery force to drive the actuator to move upward, quickly adjusting the tip clearance and realizing the active control of the tip clearance of the aeroengine.

[0017] In the patent "A Novel Automatic Light-Tracking Mechanism Based on Shape Memory Alloy" (Application No. 201820840598.9, Applicant: Nanjing University of Aeronautics and Astronautics, Inventors: Liu Lu, Li Chenyang, Huang Yuxiang, Cao Yaqi), through the combined use of two light-tracking mechanisms, 360° light tracking is achieved, with high sensitivity, improving the efficiency of solar energy collection by spacecraft.

[0018] In the patent "Design Scheme of Soft Robot Driven by SMA and SSMA" (Application No. 201410403563.5, Applicant: Beijing University of Aeronautics and Astronautics, Inventors: Shi Zhenyun, Liu Zhe, Yuan Peijiang, Chen Dongdong), a soft robot system is provided, which is applicable to the detection work in complex environments and unknown fields, and is based on the driving and feedback of shape memory alloy (SMA) wires and superelastic memory alloy (SSMA) wires, combined with flexible mechanism modules and foot rigid body joints.

[0019] In summary, in order to machine complex profiles through simple-shaped electrodes, based on the shape memory effect and superelasticity of shape memory alloy, this patent proposes a method and device for electrolytic machining with self-controlled deformation of shape memory alloy electrodes. Summary of the Invention

[0020] Object of the Invention:

[0021] The object of the present invention is to provide an electrolytic machining method and device that can ensure machining accuracy, simplify electrode design, shorten the machining cycle of parts, and improve machining efficiency.

[0022] Technical Solution:

[0023] An electrolytic machining method with self-controlled deformation of shape memory alloy electrodes, characterized by including the following processes:

[0024] Using shape memory alloy as the electrode material, and through heat treatment, the shape memory alloy electrode corresponds to different part profile line shapes at different temperatures;

[0025] Installing the shape memory alloy electrode with a floating fixture; the floating fixture refers to a fixture that automatically adjusts the distance between the two clamping ends according to the length of the clamping object by using a spring clamping end structure;

[0026] During machining, by regulating the temperature of the electrolyte to regulate the temperature of the shape memory alloy electrode, so that the shape memory alloy electrode deforms corresponding to the part profile line at different positions; among them, the highest temperature of the shape memory alloy is lower than its phase change temperature;

[0027] After machining is completed, using the shape memory effect of the material, heating the shape memory alloy electrode to make it return to its shape for the next machining.

[0028] The electrolytic machining method based on the self - controllable deformation of the shape memory alloy electrode is applicable to large - deformation machining. It is characterized in that the following methods are used to ensure that the shape memory alloy produces the correct deformation at the corresponding deformation temperature, and the highest temperature is lower than its phase - change temperature:

[0029] Set the phase - change temperature of the shape memory alloy electrode as \(T_0^{\circ}C\), and the initial temperature of the electrolyte as \(T_1^{\circ}C\). During the large - deformation machining process, the shape memory alloy electrode undergoes \(i\) deformations in total. The machining time interval between each deformation is the same. When each deformation is completed, the corresponding electrolyte temperature is \(T_1 + i\cdot\Delta T^{\circ}C\).

[0030] During the first deformation process, according to the basic laws of electrolytic machining such as Faraday's law and Ohm's law,

[0031]

[0032] \(I = i\cdot S\)

[0033] In the formula: \(U\) is the voltage between the cathode and the anode; \(i\) is the current density; \(\kappa\) is the conductivity of the electrolyte; \(\Delta\) is the machining gap; \(S\) is the machining area;

[0034] Since the resistivity of the shape memory alloy electrode is extremely low, the Joule heat generated by it is ignored. Therefore, during the machining process, the Joule heat is mainly generated by the electrolyte;

[0035]

[0036] And the rise in the electrolyte temperature caused by the Joule heat is \(T_2\)

[0037]

[0038] In the formula: \(Q\) is the Joule heat; \(t\) is the machining time; \(l\) is the proportion of the Joule heat taken away by the electrolyte;

[0039] In order to prevent the shape memory alloy electrode from generating a deformation that does not correspond to it during the first deformation process, then

[0040] \(T_2<T_1+\Delta T\)

[0041] By analogy,

[0042] \(T\) i <\(T_1 + i\cdot\Delta T\)

[0043] After simplification:

[0044]

[0045] That is, by reducing the conductivity of the electrolyte or increasing the proportion of the Joule heat taken away by the electrolyte, to ensure that the shape memory alloy electrode produces the correct deformation during the machining process.

[0046] In addition, in order to avoid the phase change of the shape memory alloy electrode, the final deformation temperature should be less than the phase change temperature of the shape memory alloy electrode

[0047] T1 + i·ΔT < T0

[0048] Therefore, it is necessary to reasonably select the deformation temperature;

[0049] After the processing is completed, using the shape memory effect of the material, the shape memory alloy electrode is heated to restore its shape for the next processing.

[0050] A device for an electrolytic machining method for realizing autonomous and controllable deformation of the shape memory alloy electrode as described above, characterized in that:

[0051] The device consists of a two-axis numerical control platform, a control system, a power supply, a pressure gauge, a water pump, a liquid supply valve, a temperature control device, a filter, an electrolyte tank, a liquid return valve, a connecting rod, a current collector, a floating fixture, a water sealing fixture, a shape memory alloy electrode, and a workpiece;

[0052] Among them, the workpiece is connected to the connecting rod by screws, and the connecting rod is installed on the X feed axis of the two-axis numerical control platform;

[0053] The current collector is installed on the Z feed axis of the two-axis numerical control platform. The shape memory alloy electrode is installed between the current collector and the two-axis numerical control platform through a floating fixture. The workpiece and the shape memory alloy electrode are sealed through a water sealing fixture;

[0054] Among them, the X feed axis and the Z feed axis of the two-axis numerical control platform are respectively connected to the positive and negative poles of the power supply through wires. The control system controls the X feed axis of the two-axis numerical control platform to move according to the set parameters through signal transmission, and the Z feed axis stops moving;

[0055] Among them, the pressure gauge, the water pump, the liquid supply valve, the temperature control device, the filter, the electrolyte tank, and the liquid return valve form an electrolyte circulation system, and the temperature control device is used to control the change of the electrolyte temperature during the processing.

[0056] The floating fixture described above consists of two groups of chucks, and they are both composed of a limit screw, a spring connecting sleeve, and a three-jaw chuck; after the three-jaw chuck holds one end of the shape memory alloy electrode, it is installed on the spring connecting sleeve; one spring connecting sleeve is installed on the current collector through a limit screw, and the other spring connecting sleeve is installed on the two-axis numerical control platform through a limit screw.

[0057] Beneficial effects:

[0058] Compared with the prior art, the present invention has the following remarkable advantages.

[0059] (1) Provided is an electrolytic machining method for the autonomous and controllable deformation of a shape memory alloy electrode, which is suitable for machining parts with complex profiles. The shape memory alloy is used as the tool electrode material, and through heat treatment, the shape memory alloy electrode corresponds to different part profile lines at different temperatures; by utilizing its shape memory effect, by regulating the temperature of the working fluid, it is convenient to realize the autonomous deformation and recovery of the electrode. Reasonably utilizing the dynamic deformation process of the autonomous recovery of the electrode can make the machined profile fit the ideal profile better.

[0060] (2) The tool electrode has good flexibility, the electrode deformation can be recovered, the electrode loss is small, and the processing cost is reduced. The tool electrode material uses a shape memory alloy. During electrolytic machining, the tool electrode serves as the cathode, and there is no loss of the electrode during the processing. Moreover, by utilizing the shape memory effect of the shape memory alloy, the electrode deformation can be recovered, and the tool electrode can be reused.

[0061] (3) The design of the tool electrode is simplified, and the machining of the tool electrode is simple. The shape of the tool electrode designed in the present invention is an elongated tubular or rod-shaped. Compared with trepanning electrolytic machining, radial feed electrolytic machining, and forming electrode electrical discharge machining, the design of the tool electrode is simple, easy to manufacture, and convenient to replace.

[0062] (4) The floating clamping method is adopted, which is beneficial to the deformation recovery of the shape memory alloy electrode and is suitable for the electrolytic machining of parts with large deformations.

[0063] (5) It has a wide range of applications. In addition to machining variable cross-section blades and open blisks, it can also machine parts with complex profiles such as closed integral blisks. According to the different profiles of the workpieces to be machined, the tool electrode can be preformed according to the characteristics of the profile curvature change for machining. In addition, the diameter of the flexible electrode can be reduced as much as possible to ensure the machining requirements of narrow channels. Description of the Drawings

[0064] Figure 1 Schematic diagram of an electrolytic machining device for the autonomous and controllable deformation of a shape memory alloy electrode without floating clamping;

[0065] Figure 2 Schematic diagram of the recovery of the shape memory alloy electrode after machining;

[0066] Figure 3 Schematic diagram of an electrolytic machining device for the autonomous and controllable deformation of a shape memory alloy electrode with floating clamping;

[0067] Figure 4 Schematic diagram of the spring connection sleeve structure;

[0068] Figure 5 Schematic diagram of the floating clamping of the shape memory alloy electrode;

[0069] Figure 6Schematic diagram of electrolytic machining with self - controllable deformation of shape memory alloy electrode;

[0070] Figure 7 Schematic diagram of self - controllable deformation of shape memory alloy electrode;

[0071] Names of the labels in the figure: 1. Biaxial numerical control platform, 2. Control system, 3. Power supply, 4. Manometer, 5. Water pump, 6. Liquid supply valve, 7. Temperature control equipment, 8. Filter, 9. Electrolyte tank, 10. Liquid return valve, 11. Connecting sleeve, 12. Three - jaw chuck, 13. Water - sealing fixture, 14. Connecting rod, 15. Current - guiding body, 16. Limit screw, 17. Spring connecting sleeve, 18. Shape memory alloy electrode, 19. Workpiece. Specific implementation method

[0072] The following will introduce the specific implementation process of the present invention in detail with reference to the accompanying drawings.

[0073] As Figure 1 shown, the non - floating clamping electrolytic machining device for implementing the "electrolytic machining method with self - controllable deformation of shape memory alloy electrode" of the present invention mainly consists of a biaxial numerical control platform 1, a control system 2, a power supply 3, a manometer 4, a water pump 5, a liquid supply valve 6, temperature control equipment 7, a filter 8, an electrolyte tank 9, a liquid return valve 10, a connecting sleeve 11, a three - jaw chuck 12, a water - sealing fixture 13, a connecting rod 14, a current - guiding body 15, a shape memory alloy electrode 18, and a workpiece 19.

[0074] As Figure 3 shown, the floating clamping electrolytic machining device for implementing the "electrolytic machining method with self - controllable deformation of shape memory alloy electrode" of the present invention mainly consists of a biaxial numerical control platform 1, a control system 2, a power supply 3, a manometer 4, a water pump 5, a liquid supply valve 6, temperature control equipment 7, a filter 8, an electrolyte tank 9, a liquid return valve 10, a connecting sleeve 11, a three - jaw chuck 12, a water - sealing fixture 13, a connecting rod 14, a current - guiding body 15, a limit screw 16, a spring connecting sleeve 17, a shape memory alloy electrode 18, and a workpiece 19.

[0075] Eight steps are required to achieve electrolytic machining of complex - shaped parts using the present invention.

[0076] Step 1: The workpiece 19 is connected to the connecting rod 14 by screws. The connecting rod 14 is installed on the X - feed axis of the biaxial numerical control platform 1, the current - guiding body 15 is installed on the Z - feed axis of the biaxial numerical control platform 1. The spring connecting sleeve 17 is installed on the current - guiding body 15 through the limit screw 16. The spring connecting sleeve 17, the three - jaw chuck 12 and the shape memory alloy electrode are floatingly clamped. The spring connecting sleeve 17 and the three - jaw chuck 12 are connected through pin holes. The three - jaw chuck 12 tightly clamps the shape memory alloy electrode 18, and the workpiece 19 and the shape memory alloy electrode 18 are sealed through the water - sealing fixture 13;

[0077] Step 2: The X-feed axis and Z-feed axis of the dual-axis CNC platform 1 are respectively connected to the positive and negative poles of the power supply 3 through wires. The control system 2 controls the X-feed axis of the dual-axis CNC platform 1 to move according to the set parameters through signal transmission, and the Z-feed axis stops moving;

[0078] Step 3: The pressure gauge 4, the water pump 5, the liquid supply valve 6, the temperature control device 7, the filter 8, the electrolyte tank 9, and the liquid return valve 10 form an electrolyte circulation system. The temperature control device 7 is used to control the change of the electrolyte temperature during the processing;

[0079] Step 4: Detect and calibrate the positions of the previously installed components;

[0080] Step 5: The power supply 3 is powered on. The control system 2 controls the X-feed axis of the dual-axis CNC platform 1 to move according to the set parameters through signal transmission. The X-feed axis drives the workpiece 19 to feed forward, and the Z-feed axis remains stationary; At the same time, the electrolyte circulation system composed of the pressure gauge 4, the water pump 5, the liquid supply valve 6, the temperature control device 7, the filter 8, the electrolyte tank 9, and the liquid return valve 10 works. The temperature control device 7 controls the change of the electrolyte temperature during the processing with the change of the processing position; The shape memory alloy electrode 18 generates corresponding deformations with the change of the electrolyte temperature. Since the shape memory alloy electrode 18, the spring connecting sleeve 17, and the three-jaw chuck 12 are floatingly clamped, the spring connecting sleeve 17 and the three-jaw chuck 12 move up and down with the deformation of the shape memory alloy electrode 18, as Figure 5 shown; The structure of the spring connecting sleeve 17 is as Figure 4 shown, and the deformation recovery process is as Figures 6-7 shown;

[0081] Step 6: After the processing is completed, the power supply 3 is powered off, the electrolyte circulation system stops working, and the shape memory alloy electrode 18 is removed;

[0082] Step 7: Heat the deformed shape memory alloy electrode 18 to the set temperature to make it recover its deformation;

[0083] Step 8: Repeat the above process to complete subsequent multiple processes.

Claims

1. An electrochemical machining method for self - controllable deformation of a shape memory alloy electrode, characterized in that It includes the following processes: A shape memory alloy is used as the electrode material, and through heat treatment, the shape memory alloy electrode corresponds to different part profile lines at different temperatures; A floating fixture is used to install the shape memory alloy electrode; the floating fixture refers to a fixture that automatically adjusts the distance between the two clamping ends according to the length of the clamped object by using a spring clamping end structure; During machining, the temperature of the shape memory alloy electrode is regulated by regulating the temperature of the electrolyte, so that the shape memory alloy electrode deforms corresponding to the part profile line at different positions; where the maximum temperature of the shape memory alloy is lower than its phase transition temperature; The following methods are used to ensure that the shape memory alloy produces the correct deformation at the corresponding deformation temperature and the maximum temperature is lower than its phase transition temperature: The phase transition temperature of the shape memory alloy electrode (18) is set to T0 °C, and the initial temperature of the electrolyte is T1 °C. During the large deformation machining process, the shape memory alloy electrode (18) undergoes i deformations in total, and the machining time interval between each deformation is the same. When each deformation is completed, the corresponding electrolyte temperature is T1 + i·ΔT °C; During the first deformation process, according to Faraday's law and Ohm's law, I = i·S In the formula: U is the voltage between the cathode and the anode; i is the current density; k is the conductivity of the electrolyte; Δ is the machining gap; S is the machining area; Since the resistivity of the shape memory alloy electrode (18) is extremely low, the Joule heat generated by it is ignored. Therefore, during the machining process, the Joule heat is mainly generated by the electrolyte; And the rise in the temperature of the electrolyte after machining caused by the Joule heat is T2 In the formula: Q is the Joule heat; t is the machining time; l is the proportion of the Joule heat taken away by the electrolyte; In order to avoid the shape memory alloy electrode (18) generating a deformation that does not correspond to it during the first deformation process, then T2 < T1 + ΔT By analogy, T i <T1 + i·ΔT After simplification: That is, by reducing the conductivity of the electrolyte or increasing the proportion of the Joule heat taken away by the electrolyte, it is ensured that the shape memory alloy electrode (18) produces the correct deformation during the machining process; In addition, in order to avoid the phase transition of the shape memory alloy electrode (18), the final deformation temperature should be less than the phase transition temperature of the shape memory alloy electrode (18) T1 + i·ΔT < T0 Therefore, it is necessary to reasonably select the deformation temperature; After the machining is completed, using the shape memory effect of the material, the shape memory alloy electrode is heated to restore its shape for the next machining.

2. A device for implementing the electrochemical machining method for self - controllable deformation of a shape memory alloy electrode according to claim 1, characterized in that: The device is composed of a biaxial numerical control platform (1), a control system (2), a power supply (3), a pressure gauge (4), a water pump (5), a liquid supply valve (6), a temperature control device (7), a filter (8), an electrolyte tank (9), a liquid return valve (10), a connecting rod (14), a current - conducting body (15), a floating fixture, a water - sealing fixture (13), a shape memory alloy electrode (18), and a workpiece (19); Among them, the workpiece (19) is connected to the connecting rod (14) through a screw, and the connecting rod (14) is installed on the X feed axis of the biaxial numerical control platform (1); The current conductor (15) is installed on the Z feed axis of the biaxial numerical control platform (1). The shape memory alloy electrode (18) is installed between the current conductor (15) and the biaxial numerical control platform (1) through a floating fixture. The workpiece (19) and the shape memory alloy electrode (18) are sealed through a water sealing fixture (13); Among them, the X feed axis and the Z feed axis of the biaxial numerical control platform (1) are respectively connected to the positive and negative poles of the power supply (3) through wires. The control system (2) controls the X feed axis of the biaxial numerical control platform (1) to move according to the set parameters through signal transmission, and the Z feed axis stops moving; Among them, a manometer (4), a water pump (5), a liquid supply valve (6), a temperature control device (7), a filter (8), an electrolyte tank (9), and a liquid return valve (10) form an electrolyte circulation system, and the temperature control device (7) is used to regulate the change in the electrolyte temperature during the processing; The floating fixture described above consists of two sets of chucks, and each of them is composed of a limit screw (16), a spring connecting sleeve (17), and a three-jaw chuck (12); after the three-jaw chuck (12) clamps one end of the shape memory alloy electrode, it is installed on the spring connecting sleeve (17); one spring connecting sleeve (17) is installed on the current collector (15) through the limit screw (16), and the other spring connecting sleeve (17) is installed on the two-axis numerical control platform (1) through the limit screw (16).

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