Helical structure flexible electrode and processing method and application thereof

Abstract

The present application relates to a kind of spiral structure flexible electrode and its processing method and application, belong to electrolytic processing technical field.The electrode is composed of processing area and non-processing area, processing area is located in the middle of electrode, side wall is spiral structure, and have spiral liquid gap;Non-processing area is located in the both ends of electrode, side wall has no liquid gap.In the process of electrolytic processing, the electrode is continuously fed along the cutting direction, while bearing load produces bending deformation, workpiece material is continuously dissolved, so as to process predetermined profile.The design of the electrode considers elasticity, stiffness and liquid flow field and other factors, and can adapt to the requirements of electrode bending deformation electrolytic processing.In addition, the electrode is simple to make, can be reused, reduces the preparation time of cathode, is suitable for processing closed integral blisk and other complex profiles.

Description

TECHNICAL FIELD

[0001] The present application relates to a spiral structure flexible electrode and its processing method and application, and belongs to the technical field of electrolytic processing. BACKGROUND

[0002] Blisk is the core component of the new generation of aero-engine, which designs the blade and the disk as a whole, simplifies the engine structure, significantly reduces the number and weight of engine components, eliminates the friction between the tenon and the blade, and improves the thrust-to-weight ratio of the engine. Blisk is made of difficult-to-mill materials such as nickel-based high-temperature alloy and new titanium alloy, and has complex structure and high precision requirements for blade profile, so the manufacturing cost is high and the cycle is long. Electrochemical machining has the advantages of not being limited by the mechanical properties of metal materials, high processing efficiency, no tool wear, no recast layer, no residual stress and micro-cracks, and has become an important method for processing complex aero-engine components.

[0003] The electrochemical machining process of blisk mainly includes two steps, rough machining of cascade channel and precision machining of blade profile. The electrochemical machining method of blisk cascade channel mainly includes sleeve machining electrochemical machining and forming electrode electrochemical machining. The precision machining of blisk profile is mainly through the opposite feeding of two forming cathodes to process the blade profile.

[0004] In the patent "Double-blade sleeve electrochemical machining device and its processing method" (application number 202010425084.9 applicant Nanjing University of Aeronautics and Astronautics, inventor Zhu Dong Zhang Xiaobo Lin Jiahao), for the whole component with large and small blades, two kinds of whole tool cathodes are designed, the tool cathode is fed along the axial direction, the double-blade rapid sleeve machining is realized, the double-flow channel flow field is designed to ensure that the two-blade machining area has sufficient electrolyte, the cathode front edge end face is coated with an insulating layer, and an insulating block is added at the rear edge tail to isolate the non-machining area of the cathode from the workpiece, and protect the base body of the workpiece disc and the tail edge of the blade.

[0005] In the patent "Blisk electrochemical grooving processing ring electrode and process method" (application number 201210367002.5 applicant Shenyang Liming Aero-engine (Group) Co., Ltd., inventor Zhu Hainan Yang Jianshi Yu Bing Li Wei), through the method of sleeve electrochemical machining, the efficient machining of wide-chord and large-torsion-angle slot of blisk profile channel is realized.

[0006] In the patent "A method and electrolytic tool for integrated electrolytic machining of blisk" (Application No. 201911225268.4, Applicant: Hefei University of Technology, Inventors: Zhang Juchen, Li Xinglin, Chen Yuanlong, Zhang Bin), a multi-axis linkage of a curved cathode is proposed to realize the integrated electrolytic machining tool of the blade basin, blade back and hub of the complex surface blisk. The cathode is a hollow thin-walled structure designed according to the blade passage and hub surface. High dimensional accuracy and high surface quality of the aerospace engine blisk workpiece can be obtained by one-time machining.

[0007] In the patent "Blisk blade electrolytic finishing forming device and blisk blade machining forming method thereof" (Application No. 201310590896.9, Applicant: Yancheng Institute of Technology, Inventors: Wang Fuyuan, Xu Jiawen, Zhao Jianshe), the main electrolyte enters the flow guide area through the main flow guide gap, and the rest of the electrolyte enters the liquid supplementing cavity through the liquid supplementing guide gap. The machining gap is supplemented from the top, and it forms a stable machining flow field together with the main electrolyte.

[0008] In the patent "Blisk surface electrolytic machining device and method based on three-dimensional composite flow field" (Application No. 201310453440.8, Applicant: Nanjing University of Aeronautics and Astronautics, Inventors: Liu Jiawan, Long Kai, Xu Zhengyang, Zhu Dong), the designed three-dimensional composite flow field can improve the pressure of the fluid in the flow channel mutation area and improve the accessibility of the flow field. At the same time, the electrolytic machining device ensures the stability of the electrolyte flow field, and realizes the stable machining of the blisk surface.

[0009] In the patent "Multi-electrode spiral feed blisk interblade passage electrolytic machining method" (Application No. 200910025834.7, Applicant: Nanjing University of Aeronautics and Astronautics, Inventors: Zhu Di, Xu Qing, Xu Zhengyang), the machine tool translation table drives multiple tool electrodes to feed linearly along the axis direction of the blisk blank at the same time. The rotary table on the translation table drives multiple tool electrodes to rotate, at the same time, the blisk blank rotates around its own axis, and the tool electrode performs electrolytic machining along the motion trajectory determined by the above-mentioned combined motion. Through the multi-dimensional interpolation motion between the tool cathode and the workpiece anode, the tubular electrode is used to machine the blade passage.

[0010] After the closed blisk increases a whole circle of shroud at the edge of the blade, the flutter of the blade can be effectively suppressed, and the overall strength and stiffness of the blisk are improved. Due to the existence of the outer ring, the closed blisk has the characteristics of closed flow channel and narrowness compared with the open blisk. In order to improve the aerodynamic characteristics of the blade, the blade surface often adopts a large twist free-form surface, which increases the bending and twisting degree of the interblade passage, and even the blades block each other, which increases the machining difficulty of the closed blisk.

[0011] In the patent "A closed whole blade disc flow passage electrolytic machining equipment and method" (application number 202111247203.7 applicant Nanjing Hangpu Machinery Technology Co., Ltd., inventor Yang Liuli Liu Chao Zhao Jian She Zhang Changhao), the flow passage is processed by turning over, the blade disc blank is turned over, the exhaust side allowance is in a position that can be reached by linear feeding, and the exhaust port cathode is used for processing and removal. The tool accessibility is good, the processing efficiency is high, and the processing cycle can be shortened.

[0012] In the patent "Flexible electrode dynamic deformation electrolytic machining method and application" (application number 202110860375.5 applicant Nanjing University of Aeronautics and Astronautics, inventor Zhu Di Xu Zhengyang Liu), a flexible electrode dynamic deformation electrolytic machining method and its application in machining closed blade discs are proposed. Through a simple-shaped electrode, complex surfaces such as closed whole blade discs are machined, and the electrolytic machining efficiency and machining precision are improved.

[0013] Electrochemical machining is a copy processing technology that obtains a target profile by designing a shaped cathode. For complex profiles, the design of the shaped cathode is also relatively complex. For example, the cathode design and preparation cycle of whole blade disc parts are often long, which limits the improvement of the machining efficiency. Flexible electrode dynamic deformation electrolytic machining is a new technology that realizes complex surface machining through a simple-shaped cathode, and is suitable for electrolytic machining of complex surfaces such as closed whole blade discs. As an important carrier in the whole machining process, the flexible electrode has high requirements for its elasticity, conductivity and other properties. The structural design of the flexible electrode plays a decisive role in the uniformity and stability of the flow field, and the vibration of the flexible electrode during the machining process has an important influence on the machining stability. Therefore, the present application proposes a spiral structure flexible tube electrode from the aspects of elasticity, vibration, conductivity and machining flow field, and introduces its application in the electrolytic machining of closed whole blade discs. SUMMARY

[0014] The purpose of the present application is to provide a spiral structure flexible tube electrode, which meets the performance requirements of elasticity, vibration, conductivity and flow field, is suitable for flexible tube electrode bending deformation electrolytic machining process, can be applied to machining various complex surfaces such as complex surfaces of closed whole blade discs, can be reused, improves the electrolytic machining efficiency, shortens the preparation cycle and reduces the machining cost.

[0015] A spiral structure flexible tube electrode, characterized in that:

[0016] The spiral structure flexible tube electrode is divided into a machining area and a non-machining area. The machining area is located at the middle position of the flexible tube electrode, the side wall thereof is in a spiral structure, and there is a spiral liquid outlet gap. The non-machining area is located at both ends of the electrode, and the side wall thereof has no liquid outlet gap.

[0017] The spiral structure flexible tube electrode has the following characteristics:

[0018] The design of the spiral structure flexible pipe electrode should consider its elasticity, rigidity and flow field performance requirements, and the following is an example of circular cross-section equidistant design.

[0019] (1) Elasticity requirement: the flexible pipe electrode can fully recover its original shape after bending deformation, that is, only elastic deformation occurs, no plastic deformation occurs. During the bending deformation of the flexible pipe electrode, the outer side is stretched and the inner side is compressed, so the outer side stretching amount and the inner side compression amount should be less than the limit deformation amount of its elastic deformation.

[0020] According to the basic principles of theoretical mechanics and material mechanics, the following formula is derived:

[0021] The deformation amount of the outer side stretching and the inner side compression of the flexible pipe electrode processing area:

[0022]

[0023] The maximum allowable tensile and compressive stress of the flexible pipe electrode processing area:

[0024]

[0025] The rigidity coefficient of the flexible pipe electrode processing area:

[0026]

[0027] In the formula: D is the diameter of the flexible pipe electrode; n is the number of spiral turns of the flexible pipe electrode processing area; t is the pitch of the flexible pipe electrode processing area; R is the bending curvature radius of the flexible pipe electrode; τ s is the allowable shear stress of the flexible pipe electrode material; d is the wire diameter of the flexible pipe electrode; G is the shear modulus of the flexible pipe electrode material.

[0028] According to the above formula, the limit deformation amount of the elastic deformation of the flexible pipe electrode processing area:

[0029]

[0030] To ensure that the flexible pipe electrode can fully recover after bending deformation, the outer side stretching amount and the inner side compression amount should be less than the limit deformation amount of its elastic deformation, that is:

[0031] X1<X2

[0032] After substitution and arrangement:

[0033]

[0034] In the design process of the flexible pipe electrode, first determine its minimum curvature radius R minThen the structure and material parameters of the flexible tube electrode are brought into the above formula, and the elastic requirement is met by satisfying the above formula. In actual use, the curvature radius of the flexible tube electrode at each position needs to be greater than R min .

[0035] (2) Rigidity requirement: In the process of electrochemical machining, the flexible tube electrode will inevitably vibrate. In order to ensure the smooth progress of the machining, the vibration amplitude of the flexible tube electrode needs to be less than the machining gap of the electrochemical machining. The amplitude of the flexible tube electrode is related to the electrolyte flow and its own rigidity, and its rigidity coefficient is:

[0036]

[0037] In order to improve the rigidity of the flexible tube electrode, a material with a larger shear modulus G can be selected, a larger wire diameter d can be selected, a smaller pitch D and a smaller number of spiral turns n can be selected, thereby reducing the amplitude during electrochemical machining and improving the efficiency of electrochemical machining.

[0038] (3) Flow field requirement: The flow field of the flexible tube electrode needs to be stable, uniform and fast to carry away the products of electrochemical machining and meet the requirements of electrochemical machining. In order to ensure that there is enough electrolyte in the electrochemical machining gap and the speed of the electrolyte is relatively fast, there needs to be enough space in the tube electrode for the electrolyte to flow through. Therefore, the size of the inner diameter of the tube electrode has a great influence on the flow field. Generally speaking, the larger the inner diameter of the tube electrode, the more conducive the flow field is to electrochemical machining. According to the experience of tube electrode machining test and finite element simulation, the electric field strength at the outlet gap is weak, which will affect the morphology of the machining surface. If the gap is too large, a small boss will be formed on the machining surface, which will affect the electrolyte from being sprayed out of the tube. If the gap is too small, the overall flow will be reduced. Therefore, the outlet gap should be as fine as possible within a certain range.

[0039] In order to obtain a better flow field, a larger pitch D and a smaller wire diameter d can be selected, and a suitable machining area pitch t can be selected. In actual design, all requirements need to be considered comprehensively to design the optimal parameters that meet the actual application.

[0040] The machining method of the above spiral structure flexible tube electrode, characterized in that it comprises the following machining methods

[0041] Machining method one, winding type machining, using metal wire material to form spiral winding, leaving a set outlet gap between adjacent spirals in the middle machining area, and no gap between adjacent spirals in the non-machining area at both ends and tightly adhering, the metal wire material is a material with good elasticity and conductivity such as elastic alloy, the cross section of the metal wire material is circular or rectangular; the rigidity and flow field of the flexible tube electrode as a whole are changed by adjusting the cross section shape and size; the rigidity and flow field of the flexible tube electrode at different positions are changed by adjusting the size and distribution of the outlet gap between adjacent spirals in the machining area;

[0042] The second processing mode is cutting processing, which cuts a straight pipe to form a spiral groove liquid outlet structure in the middle processing area, and retains the shape of the initial pipe in the non-processing area at both ends.

[0043] The application of the spiral structure flexible pipe electrode in bending deformation electrolytic processing is characterized in that:

[0044] The flexible pipe electrode is clamped by a chuck at both ends and connected to a negative pole of a power supply, an anode workpiece is connected to a positive pole of the power supply, electrolyte flows in from both ends of the flexible pipe electrode through the chuck, passes through the liquid outlet gap of the processing area of the flexible pipe electrode, and flows into the processing gap; during the electrolytic processing, the flexible pipe electrode is continuously fed along the cutting direction, and is bent according to a predetermined shape under the driving of the chuck at both ends, and the anode workpiece material is continuously dissolved, so that a predetermined profile is processed;

[0045] Since the tool electrode used is the flexible pipe electrode, the flexible pipe electrode will inevitably vibrate under the impact of the electrolyte, the vibration amplitude of the flexible pipe electrode is related to the electrolyte flow field and the rigidity of the flexible pipe electrode, and the processing gap of the electrolytic processing is related to the electrolytic processing parameters such as processing voltage and feed speed, in order to realize a stable electrolytic processing process, the electrolytic processing parameters need to be controlled according to the processing requirements, so that the amplitude of the flexible pipe electrode in any direction is less than the processing gap in the direction; in the electrolytic processing process, the spiral structure of the processing area of the flexible pipe electrode is similar to a spiral coil, and a magnetic field is generated when current passes through, and has inductance, which shows the characteristics of blocking alternating current when passing through direct current and blocking high frequency when passing through low frequency, therefore, direct current is selected for processing, and the negative poles of the power supply are connected to both ends of the flexible pipe electrode.

[0046] Compared with the prior art, the application has the following advantages.

[0047] (1) A spiral structure flexible pipe electrode is provided, which has good flexibility, rigidity and conductivity, can be repeatedly elastically deformed and rebounded, the bending deformation shape can be controlled, and is suitable for electrolytic processing.

[0048] (2) The electrolyte flow field of the flexible pipe electrode is a spiral jet flow field, which can jet liquid in all directions, and compared with the hole jet or slit jet of the conventional pipe electrode, the flow field is more uniform.

[0049] (3) A double-spiral structure flexible pipe electrode is provided, which has greater rigidity and smaller resistance than the single-spiral structure, and has better overall performance, and is more suitable for flexible pipe electrode bending deformation electrolytic processing.

[0050] (4) The application has wide application range, and can be used for processing blades with simple cross section or complex profile such as closed integral blade disc. BRIEF DESCRIPTION OF DRAWINGS

[0051] Figure 1 It is a structure schematic diagram of the flexible pipe electrode with helical structure.

[0052] Figure 2 It is a structure schematic diagram of the flexible pipe electrode when being bent and deformed.

[0053] Figure 3 It is a flow field schematic diagram of the flexible pipe electrode when being used for electrolytic processing.

[0054] Figure 4 It is a structure schematic diagram of the flexible pipe electrode when being used for electrolytic processing.

[0055] Figure 5 It is a structure schematic diagram of the flexible pipe electrode when being used for electrolytic processing.

[0056] Figure 6 It is a structure schematic diagram of the flexible pipe electrode with double helical structure.

[0057] Figure 7 It is a structure schematic diagram of the flexible pipe electrode when being used for electrolytic processing of the closed integral blade disc.

[0058] In the figure, the label name is: 1, flexible pipe electrode, 2, workpiece, 3, chuck, 4, closed integral blade disc workpiece. DETAILED DESCRIPTION

[0059] The specific implementation process of the application will be described in detail below with reference to the accompanying drawings.

[0060] The structure of the flexible pipe electrode with helical structure is shown in the figure. Figure 1 The structure of the flexible pipe electrode with helical structure is shown in the figure. Figure 1 The flexible pipe electrode with helical structure is shown in the figure. Figure 1b is a flexible tube electrode using cutting type machining method, which uses turning, electric spark, etc. machining method to cut straight tube, cut out spiral groove outflow structure in middle machining area, keep the shape of initial tube in both ends non machining area, the material of straight tube can be elastic alloy and other materials with good elasticity and conductivity.

[0061] The structure of the flexible tube electrode with spiral structure in bending deformation is shown in Figure 2 The inside spiral gap of the machining area is compressed, the outside spiral gap is stretched, the non machining area has initial tension and is less affected by bending moment, so it does not bend or only has a small amount of bending, therefore although the overall flexible tube electrode bends greatly, the local deformation is still within the elastic deformation range of the material, and repeated bending deformation and springback can be achieved.

[0062] The electrolyte flow field of the flexible tube electrode with spiral structure in initial state and bending state is shown in Figure 3 a and 3b. During electrolytic machining, electrolyte is injected from both ends of the flexible tube electrode, sprayed from the machining area gap of the flexible tube electrode, flows into the machining gap, and participates in the electrochemical reaction.

[0063] The variable gap distribution of the machining area of the flexible tube electrode with spiral structure is shown in Figure 4 During electrolytic machining, electrolyte is injected from both ends of the flexible tube electrode, sprayed from the machining area gap of the flexible tube electrode, flows into the machining gap, and participates in the electrochemical reaction. Figure 4 a is a flexible tube electrode using winding type machining method, the spiral gap of the machining area is small in the middle and large on both sides, by adjusting the size and distribution of the outflow gap, the stiffness and flow field of the flexible tube electrode at different positions can be changed. Figure 4 b is a flexible tube electrode using cutting type machining method, the spiral outflow groove in the middle of the machining area is sparse, and the two sides are dense, by adjusting the wall thickness of the straight tube, the width of the spiral groove and the distance between adjacent grooves, the stiffness and flow field of the flexible tube electrode can be changed.

[0064] The flexible tube electrode with spiral structure is applied to electrolytic machining as shown in Figure 5 The flexible tube electrode 1 is clamped by the chuck 3 at both ends and connected to the negative electrode of the power supply, the workpiece 2 is connected to the positive electrode of the power supply, the electrolyte is injected from both ends of the flexible tube electrode through the chuck at both ends, sprayed from the outflow gap of the machining area of the flexible tube electrode, and finally flows into the machining gap of the electrolytic machining. During electrolytic machining, the flexible tube electrode 1 continuously feeds along the cutting direction, and at the same time, under the driving of the chuck 3 at both ends, the flexible tube electrode bends according to the predetermined shape, and the material of the anode workpiece 2 is continuously dissolved, so as to machine the predetermined profile.

[0065] Since the tool electrode used is the flexible tube electrode 1, the flexible tube electrode 1 will inevitably vibrate under the impact of the electrolyte, the vibration amplitude of the flexible tube electrode 1 is related to the electrolyte flow field and the rigidity of itself, the machining gap of the electrochemical machining is related to the machining voltage, the feed speed and other electrochemical machining parameters, in order to realize a stable electrochemical machining process, the electrochemical machining parameters need to be controlled according to the machining requirements, so that the amplitude of the flexible tube electrode 1 in any direction is less than the machining gap in the direction. In the electrochemical machining process, the spiral structure of the machining area of the flexible tube electrode 1 is similar to a spiral coil, and a magnetic field will be generated when current passes through, and has inductive reactance, which shows the characteristics of blocking alternating current when passing through direct current and blocking high frequency when passing through low frequency, therefore, direct current is selected for machining, and the two ends of the flexible tube electrode 1 are connected to the negative pole of the power supply.

[0066] The double-spiral structure flexible tube electrode structure of the application is shown in Figure 6 The machining area of the flexible tube electrode is a symmetrical double-spiral structure, which has greater rigidity and smaller resistance than the single-spiral structure, and has better overall performance, and is more suitable for flexible tube electrode bending deformation electrochemical machining. When there are three or more spirals, the different spiral structures cannot be completely symmetrical, and the asymmetric spiral structures will be subjected to different forces when bending and deforming, which will cause the side wall to be uneven, and if applied to flexible tube electrode bending deformation electrochemical machining, it will cause the machining surface to be uneven. Therefore, the double-spiral structure is the best choice for the spiral structure flexible tube electrode.

[0067] The spiral structure flexible tube electrode of the application is applied to closed integral blade disc electrochemical machining as shown in Figure 6 The closed integral blade disc workpiece 4 is connected to the positive pole of the electrochemical machining power supply, and the two ends of the flexible tube electrode 1 are connected to the negative pole of the electrochemical machining power supply through the chuck 3. Before electrochemical machining, the closed integral blade disc workpiece 4 needs to be machined by a mechanical machining method to form through holes with the same number of blades, the width of the through hole should be greater than the diameter of the flexible tube electrode 1, and the flexible tube electrode 1 passes through the through hole of the closed integral blade disc workpiece 4. During electrochemical machining, the electrolyte is introduced, the electrochemical machining power supply is turned on, and the flexible tube electrode 1 is bent and deformed under the driving of the chuck 3, and moves radially inward along the closed integral blade disc workpiece 4 to complete the electrochemical machining of the closed integral blade disc passage profile.

Claims

1. A spiral structure flexible tube electrode, characterized in that: the spiral structure flexible tube electrode is divided into a processing area and a non-processing area, the processing area is located in the middle of the flexible tube electrode, the side wall of which is in a spiral structure and has a spiral liquid outlet gap, and the non-processing area is located at both ends of the electrode, the side wall of which has no liquid outlet gap; both ends of the flexible tube electrode are clamped by a chuck and connected to a negative electrode of a power supply, a positive electrode workpiece is connected to a positive electrode of the power supply, and an electrolyte flows into the processing gap through the liquid outlet gap of the processing area of the flexible tube electrode from both ends of the flexible tube electrode; during the electrolytic processing, the flexible tube electrode is continuously fed along the cutting direction, and at the same time, the flexible tube electrode is bent according to a predetermined shape under the driving of the chuck at both ends, and the material of the positive electrode workpiece is continuously dissolved, so that a predetermined profile is processed; since the tool electrode used is a flexible tube electrode, the flexible tube electrode will inevitably vibrate under the impact of the electrolyte, the vibration amplitude of the flexible tube electrode is related to the electrolyte flow field and its own stiffness, the processing gap of the electrolytic processing is related to the electrolytic processing parameters such as processing voltage and feed speed, in order to realize a stable electrolytic processing process, the electrolytic processing parameters need to be controlled according to the processing requirements, so that the amplitude of the flexible tube electrode in any direction is less than the processing gap in that direction; during the electrolytic processing, the spiral structure of the processing area of the flexible tube electrode is similar to a spiral coil, and a magnetic field is generated when current passes through, and has inductive reactance, which shows the characteristics of blocking alternating current when passing through direct current and blocking high frequency when passing through low frequency, therefore, direct current is selected for processing, and both ends of the flexible tube electrode are connected to the negative electrode of the power supply.

2. The spiral structure flexible tube electrode according to claim 1, characterized in that: the design of the spiral structure flexible tube electrode needs to consider its elasticity, stiffness and flow field performance requirements; elasticity requirement: the flexible tube electrode can completely recover to the initial shape after bending deformation by relying on its own elasticity, that is, only elastic deformation occurs, and no plastic deformation occurs; during the bending deformation of the flexible tube electrode, the outside is stretched and the inside is compressed, so the outside stretching amount and the inside compression amount need to be less than the limit deformation amount of the elastic deformation; according to the basic principles of theoretical mechanics and material mechanics, the following formulas are derived: the outside stretching and inside compression deformation amount of the processing area of the flexible tube electrode: ； the maximum allowable tension and compression force of the processing area of the flexible tube electrode: ； the stiffness coefficient of the processing area of the flexible tube electrode: ； where: D is the diameter of the flexible tube electrode; n is the number of spirals in the processed region of the flexible tube electrode; t is the pitch of the processed region of the flexible tube electrode; R is the bending radius of curvature of the flexible tube electrode; is the allowable shear stress of the flexible tube electrode material; d is the diameter of the flexible tube electrode; G is the shear modulus of the flexible tube electrode material; according to the above formulas, the limit deformation amount of the elastic deformation of the processing area of the flexible tube electrode: ； in order to ensure that the flexible tube electrode can completely rebound after bending deformation, the outside stretching amount and the inside compression amount need to be less than the limit deformation amount of the elastic deformation, that is: ； after arrangement, we get: ； In the design of the flexible pipe electrode, first, the minimum curvature radius of the flexible pipe electrode when bending and deforming is determined Then, the specific structure and material parameters of the flexible pipe electrode are brought into the above formula, and the above formula is satisfied, that is, the elastic requirement is satisfied. In actual use, the curvature radius of each part of the flexible pipe electrode when bending and deforming needs to be greater than ; (2) stiffness requirement: during the electrolytic processing, the flexible tube electrode will inevitably vibrate, in order to make the processing proceed smoothly, the vibration amplitude of the flexible tube electrode needs to be less than the electrolytic processing gap; the amplitude of the flexible tube electrode is related to the electrolyte flow and its own stiffness, and its stiffness coefficient is: ； In order to improve the rigidity of the flexible tube electrode, a material with a greater shear modulus G is selected, the wire diameter d is greater, the pitch D is smaller and the number of turns n is less, so as to reduce the amplitude during the electrolytic machining and improve the electrolytic machining efficiency; (3) Flow field requirements: the flow field of the flexible tube electrode needs to be stable, uniform and fast to carry away the electrolytic machining products and meet the electrolytic machining requirements; in order to ensure that there is enough electrolyte in the electrolytic machining gap and the speed of the electrolyte is relatively fast, there needs to be enough space in the tube electrode for the electrolyte to flow through; therefore, the size of the inner diameter of the tube electrode has a great influence on the flow field; in general, the larger the inner diameter of the tube electrode, the more conducive the flow field is to electrolytic machining; according to the tube electrode machining test experience and finite element simulation, the electric field strength at the outlet gap is weak, which will affect the morphology of the machining surface; If the gap is too large, a small boss will be formed on the machining surface, which will affect the electrolyte from being sprayed out of the tube; if the gap is too small, the overall flow will be reduced; therefore, the outlet gap should be as fine as possible within a certain range; In order to obtain a better flow field, a larger pitch D and a smaller wire diameter d are selected, and a suitable machining area pitch t is selected; in actual design, various requirements need to be considered comprehensively to design the optimal parameters that meet the actual application.

3. The spiral structure flexible tube electrode according to claim 1, characterized in that: The machining area of the flexible tube electrode is a single spiral structure or a symmetrical double spiral structure.

4. The method of claim 1, wherein The following machining methods are included: Machining method one, winding type machining, using metal wire material to form a spiral winding, leaving a set outlet gap between adjacent spirals in the middle machining area, and no gap between adjacent spirals in the non-machining area at both ends and tightly adhering, the metal wire material is a material with good elasticity and conductivity such as elastic alloy; by adjusting the cross-sectional shape and size to change the rigidity and flow field of the flexible tube electrode as a whole, the outlet gap between adjacent spirals in the machining area is equal or variable, and by adjusting the size and distribution of the outlet gap to change the rigidity and flow field of the flexible tube electrode at different positions; Machining method two, cutting type machining, cutting a straight tube to cut a spiral groove outlet structure in the middle machining area, and keeping the shape of the original tube in the non-machining area at both ends, the straight tube material is a material with good elasticity and conductivity such as elastic alloy, and the rigidity and flow field of the flexible tube electrode are changed by adjusting the wall thickness of the straight tube, the width of the spiral groove and the distance between adjacent grooves.

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