Device and method for segmented synchronous electrochemical machining of the inlet / exhaust edges of large-twist blades

Abstract

This invention relates to a segmented synchronous electrolytic machining device and method for the inlet / outlet edges of blades with large torsion angles, belonging to the field of electrolytic machining technology. The device is characterized by dividing the inlet / outlet edges of a blade with a large torsion angle into two segments with smaller torsion angles along a specific cross section, and designing two cathodes for each segment, enabling segmented synchronous electrolytic machining of the inlet / outlet edges by the two cathodes with different feed directions. The device mainly includes a segmented synchronous feed mechanism and inlet / outlet edge tool cathodes. The segmented synchronous feed mechanism is mounted on the machine tool spindle, and a pair of wedge mechanisms can transform the single-direction feed of the spindle into synchronous cross-feeding of the two tool cathodes. The tool cathodes are mounted at the front end of the segmented synchronous feed mechanism, and the upper and lower sides of the cathode housing are respectively provided with a main liquid inlet and an auxiliary liquid inlet, forming an open electrolyte flow field with the blade. This invention solves the problem of the inability to electrolytically machine the inlet / outlet edges of blades with large torsion angles, improving the machining accuracy and efficiency of the inlet / outlet edges.

Description

Technical Field

[0001] This invention belongs to the field of electrolytic machining technology, and particularly relates to a device and method for simultaneous electrolytic machining of the intake / exhaust sides of blades with large torsion angles. Background Technology

[0002] Blades are one of the key components of modern aero engines. New aero engine blades often adopt increasingly complex structural forms such as wide chord and swept blades. With a large number of blades, large changes in surface curvature, end bends and sweepbacks, the requirements for their geometric accuracy and overall quality are becoming increasingly high. In particular, the requirements for dimensional accuracy and geometry at the inlet / outlet edges of the blades are becoming increasingly stringent, and the forming and processing and surface integrity assurance are becoming increasingly difficult.

[0003] Currently, the main machining methods for inlet / outlet edges include milling, grinding, and electrochemical machining. Milling is a machining method that removes material from a workpiece using a high-speed rotating milling cutter. With the development of multi-axis CNC machining technology, the application range of milling has become more extensive, and it can now be applied to the precision machining of tortuous structures such as blade inlet / outlet edges. However, because milling is a contact machining process, there is a macroscopic cutting force between the tool and the workpiece. When machining small-sized inlet / outlet edge structures, this can cause workpiece deformation, reducing machining accuracy. Furthermore, if the tool shape, machining parameters, or machining trajectory planning are inappropriate, it can lead to tool marks and microcracks on the workpiece surface. Grinding, as a precision shaping process, is often used for the precision machining of blade inlet / outlet edges. During machining, a certain machining allowance needs to be reserved in the previous process. Precision grinding is used to precisely shape the inlet / outlet edges, producing high-precision, high-surface-quality inlet / outlet edge structures. However, current inlet / outlet edge grinding processes are difficult to automate, and their machining efficiency needs further improvement.

[0004] Electrolytic machining (EMC) is a machining method based on the principle of electrochemical anodic dissolution to remove metal materials. During the process, the workpiece is connected to the positive terminal of the power supply, and the tool cathode is connected to the negative terminal, with a very small machining gap between the two electrodes. The electrolyte flows at high speed through this gap. Under the influence of an electric field, oxidation-reduction reactions occur on the surfaces of the two electrodes within the machining gap. Oxidation occurs at the anode, removing the metal material in the form of ions; reduction occurs at the cathode, releasing hydrogen gas. During the machining process, the tool cathode is continuously fed, and material is gradually removed from the workpiece surface, gradually shaping it. EMC is a non-contact machining process, not limited by the mechanical properties of the material, and features no cutting force and no cutting heat. It has a natural advantage in machining small, thin-walled parts, making it ideal for machining the inlet / outlet edges of blades.

[0005] Traditional blade inlet / outlet edge machining relies on the cathodes on the blade base and back of the blade being fed in opposite directions. This process shapes the inlet / outlet edge structure while machining the blade profile. However, because the curvature at the inlet / outlet edge varies significantly compared to the blade profile, the electric and flow fields at the inlet / outlet edge constantly change during actual machining, making it difficult to guarantee machining accuracy. The tangential feed electrolytic machining method for inlet / outlet edges, after the blade profile has been machined, involves feeding a dedicated inlet / outlet edge tool cathode tangentially along the blade's mid-curve to remove machining allowances, thus achieving precision machining of the inlet / outlet edges. This method offers significant advantages over traditional bidirectional feed machining methods in terms of cathode and flow field design, and holds immense potential for blade inlet / outlet edge machining.

[0006] The patent "Design Method of Three Elements for Leading and Trailing Edge Cathodes for Precision Electrolysis of Aero-engine Blades" (application number 202210632192.2, applicant: Jiangsu Jicui Precision Manufacturing Research Institute Co., Ltd., inventors: Wang Zhongheng, He Chao, Zhao Jianshe, Zhang Changhao, Gao Weizheng) proposes to design cathodes by optimizing the three elements of leading and trailing edge cathode design, thereby reducing the number of cathode iteration corrections and improving the machining accuracy of the leading and trailing edges of the blades.

[0007] The patent "A design method for a precision electrolytic machining electrode for the leading and trailing edges of a blade" (application number 201711249203.4, applicant: China Aero Engine Corporation Shenyang Liming Aero Engine Co., Ltd., inventors: Liu Haibo, Huan Heng, Zheng Xin, Chen Dong, Zhang Yahua) changes the surface conductivity of the cathode at the electric field concentration point at the leading and trailing edges through surface treatment, thus avoiding the problem of difficulty in ensuring the precision of electrolytic machining caused by the electric field concentration and flow field disturbance in the leading and trailing edge regions.

[0008] In the patent "An Adaptive Machining Method for the Leading and Trailing Edges of Aero-engine Turbine Blades" (application number 202110678545.8, applicant: Jiangsu Jianghangzhi Aircraft Engine Components Research Institute Co., Ltd., inventors: Wu Jiang, Cao Chunxiao, Yan Xiaolin), several evenly distributed follow-up mechanisms are set in the swing mechanism. The tool cathode and the internally set leading edge cathode one and leading edge cathode two adaptively complete the precision electrolytic machining of the leading and trailing edges of the blade, which greatly improves the machining efficiency and machining accuracy.

[0009] The patent “A Pulse Dynamic Electrolytic Machining Device for the Inlet / Exhaust Edge of a Blade or Integral Bladed Disk” (application number 202110617149.4, applicant: Nanjing University of Aeronautics and Astronautics, inventors: Zhu Di, Liu Jia, Wang Hao, Wang Jingtao) proposes a pulse dynamic electrolytic machining device for tangential feed machining along the inlet / exhaust edge. This device enables the machining process to be carried out under conditions that are much smaller than conventional machining gaps, thereby significantly improving the contour accuracy of the inlet / exhaust edge of the blade.

[0010] The patent "Precision Electrolytic Repair Tool and Method for Blade Inlet / Exhaust Sides" (application number 202210402862.1, applicant: Nanjing University of Aeronautics and Astronautics, inventors: Wang Jingtao, Liu Jia, Zhu Di, Xu Zhengyang, Wei Haodi, Wang Jing) proposes an integrated cathode for tangential feed of the inlet / exhaust side and a precision repair method for the inlet / exhaust side. During the processing, the inlet / exhaust side electrolytic machining can be achieved without disassembling any tooling fixtures and tool setting devices, which improves the automation level of inlet / exhaust side electrolytic machining to a certain extent.

[0011] However, current tangential feed electrochemical machining methods still have shortcomings in practical applications when machining blades with relatively twisted airfoils and large inlet / outlet torsion angles. Currently, the cathode feed direction of the inlet / outlet sides is along the angle bisector of the inlet / outlet torsion angle. For blades with excessively large torsion angles, this results in excessively large cathode machining angles in certain parts of the inlet / outlet sides, making it impossible to uniformly dissolve the inlet / outlet side arcs. Therefore, to overcome the problem of not being able to achieve high-precision electrochemical machining of the inlet / outlet sides of blades with large torsion angles, this invention provides a segmented synchronous electrochemical machining device and method for the inlet / outlet sides of blades with large torsion angles. Summary of the Invention

[0012] Purpose of the invention: The purpose of this invention is to overcome the bottleneck problem that high-precision electrolytic machining cannot be achieved on the intake / exhaust edges of blades with large torsion angles, and to propose a segmented synchronous electrolytic machining device and method for the intake / exhaust edges of blades with large torsion angles.

[0013] Technical solution: A method for segmented synchronous electrolytic machining of the inlet / outlet edges of a blade with a large torsion angle, characterized in that: the blade with a large torsion angle is processed in segments simultaneously, wherein the method for determining the segmented cross-section and the feed direction of the tool cathode after segmentation are determined by the following method:

[0014] Step 1. Extract the blade tip section outline and the blade root section outline from the 3D model of the blade and project them onto the same plane;

[0015] Step 2. Draw several inscribed circles in the projected outlines of the blade tip section and the blade root section respectively; and fit the mid-arc lines through the center of the inscribed circles respectively to form the mid-arc lines of the blade tip section and the blade root section respectively.

[0016] Step 3. Draw a tangent to the middle arc line at the intersection of the blade tip section and the intake edge, pointing outwards from the section profile. This is called the blade tip section middle arc line intake edge tangent. Draw a tangent to the middle arc line at the intersection of the blade root section and the intake edge, pointing outwards from the section profile. This is called the blade root section middle arc line intake edge tangent. Draw a tangent to the middle arc line at the intersection of the blade tip section and the exhaust edge, pointing outwards from the section profile. This is called the blade tip section middle arc line exhaust edge tangent. Draw a tangent to the middle arc line at the intersection of the blade root section and the exhaust edge, pointing outwards from the section profile. This is called the blade root section middle arc line exhaust edge tangent.

[0017] Step 4. Using the angle bisector of the tangent of the arc-shaped inlet side in the blade tip section and the tangent of the arc-shaped inlet side in the blade root section as the reference direction, the blade section whose tangent direction is consistent with the reference direction is used as the dividing surface of the inlet side; the angle bisector of the reference direction and the tangent direction of the arc-shaped inlet side in the blade tip section is the feed direction of the tool cathode on the blade tip side of the inlet side, and the angle bisector of the reference direction and the tangent direction of the arc-shaped inlet side in the blade root section is the feed direction of the tool cathode on the blade root side of the inlet side;

[0018] Using the angle bisector of the tangent of the arc-shaped exhaust edge in the blade tip section and the tangent of the arc-shaped exhaust edge in the blade root section as the reference direction, the blade section with the tangent direction of the arc-shaped exhaust edge aligned with the reference direction is used as the dividing surface of the exhaust edge. The angle bisector of the reference direction and the tangent direction of the arc-shaped exhaust edge in the blade tip section is the feed direction of the tool cathode on the blade tip side of the exhaust edge, and the angle bisector of the reference direction and the tangent direction of the arc-shaped exhaust edge in the blade root section is the feed direction of the tool cathode on the blade root side of the exhaust edge.

[0019] The method for simultaneous electrolytic machining of the intake / exhaust sides of the blade with a large torsion angle is characterized in that: after segmentation, the tip side and the root side of the intake side blade are machined simultaneously; or the tip side of the exhaust side blade and the root side of the exhaust side blade are machined simultaneously.

[0020] The apparatus for the segmented synchronous electrolytic machining method of the large torsion angle blade intake / exhaust edges is characterized in that:

[0021] It includes a segmented synchronous feed mechanism, a blade root side tool cathode, and a blade tip side tool cathode; the segmented synchronous feed mechanism consists of a spindle adapter block and a blade root side wedge mechanism and a blade tip side wedge mechanism;

[0022] The blade root side wedge mechanism consists of a blade root side guide rail base, a blade root side cathode base, and a blade root side guide rod. The blade root side guide rail base is fixedly installed on the machine tool platform, and the blade root side cathode base is installed on the blade root side guide rail base through a corresponding guide rail slider. The blade root side guide rod is installed in the inclined groove of the blade root side cathode base to form a pair of wedge mechanisms. The end face of the blade root side guide rod is installed on the machine tool spindle through a spindle adapter block. The blade root side tool cathode is installed on the corresponding blade root side cathode base. The angle of the blade root side wedge mechanism is consistent with the feed direction of the intake side blade root side tool cathode or the exhaust side blade root side tool cathode.

[0023] The blade tip side wedge mechanism consists of a blade tip side guide rail base, a blade tip side cathode base, and a blade tip side guide rod. The blade tip side guide rail base is fixedly installed on the machine tool platform, and the blade tip side cathode base is installed on the blade tip side guide rail base through a corresponding guide rail slider. The blade tip side guide rod is installed in the inclined groove of the blade tip side cathode base to form a pair of wedge mechanisms. The end face of the blade tip side guide rod is installed on the machine tool spindle through a spindle adapter block. The blade tip side tool cathode is installed on the corresponding blade tip side cathode base. The angle of the blade tip side wedge mechanism is consistent with the feed direction of the intake side blade tip side tool cathode or the exhaust side blade tip side tool cathode.

[0024] The method for segmented synchronous electrolytic machining of blades with large torsion angles is characterized by the following machining steps:

[0025] Step 1: Install the segmented synchronous feed mechanism on the machine tool, and connect the spindle adapter block 6) to the machine tool spindle; adjust the position of the machine tool spindle and thus adjust the position of the two segmented tool cathodes so that the two tool cathode profiles form a complete and continuous cathode profile;

[0026] Step 2: Install the blade blank in the fixture, measure and position it, and perform tool setting, while maintaining the initial machining clearance between the tip-side tool cathode, the root-side tool cathode, and the blade blank.

[0027] Step 3: Connect the blade blank to the positive terminal of the power supply, and connect the tool cathode on the blade tip side and the tool cathode on the blade root side to the negative terminal of the power supply; the flow field for processing adopts a double-sided liquid inlet countercurrent flow field, and the electrolyte is divided into four paths, flowing into the processing gap from the main liquid inlet on the blade tip side, the main liquid inlet on the blade root side, and the auxiliary liquid inlet, respectively, flowing through the inlet / outlet side, and freely flowing out from the open outlet formed by the lower guide shell on the blade tip side, the lower guide shell on the blade root side, and the blade;

[0028] Step 4: During processing, the machine tool spindle pushes the tip-side guide rod and the root-side guide rod simultaneously in the horizontal direction. The wedge mechanism formed by the tip-side guide rod and the tip-side cathode base transforms the horizontal feed of the tip-side guide rod into the feed of the tip-side cathode base along the tilt angle of the tip-side guide rail base, thereby driving the tip-side tool cathode closer to the intake / exhaust edge. The wedge mechanism formed by the root-side guide rod and the root-side cathode base transforms the horizontal feed of the root-side guide rod into the feed of the root-side cathode base along the tilt angle of the root-side guide rail base, thereby driving the root-side tool cathode closer to the intake / exhaust edge. Under the synchronous movement of the tip-side and root-side tool cathodes and the electrochemical dissolution effect, the intake / exhaust edge is formed synchronously.

[0029] Step 5: Turn off the power, electrolyte circulation system, and machine tool.

[0030] Beneficial effects: Compared with the prior art, the present invention has the following significant features:

[0031] (1) A method for tangential electrolytic machining of the inlet / outlet edges of blades with large torsion angles is proposed. The inlet / outlet edges of blades with large torsion angles are divided into two segments along a certain cross section to reduce the torsion angle of each segment. Then, the two segments of blade inlet / outlet edges are simultaneously subjected to tangential electrolytic machining. This method of segmented synchronous electrolytic machining of blade inlet / outlet edges effectively solves the problem that when machining the inlet / outlet edges of blades with large torsion angles, the angle between the feed direction and the tangent direction of the arc in the cross section profile is too large, which leads to excessive dimensional deviation of the machined inlet / outlet edges.

[0032] (2) A segmented synchronous electrolytic machining device for the inlet / outlet sides of blades with large torsion angles was designed. The linear motion of a single motion axis directly drives the two inlet / outlet side tool cathodes to move synchronously along a certain included angle direction. The synchronicity and consistency of the feed of the two tool cathodes are guaranteed, and the segmented synchronous machining of the inlet / outlet sides of blades with large torsion angles can be completed well.

[0033] (3) The tangential electrolytic machining method for the inlet / outlet edges of blades with large torsion angles has a wide range of applications and high processing flexibility. For parts such as the inlet / outlet edges of integral bladed disk blades and diffuser blades, the inlet / outlet edge tool cathode can be designed specifically for machining. Attached Figure Description

[0034] Figure 1 Schematic diagram of a segmented synchronous feed electrolytic machining device;

[0035] Figure 2 This is a partial cross-sectional view of a segmented synchronous feed electrolytic machining device;

[0036] Figure 3 Schematic diagram of segmented synchronous feed cathode for intake / exhaust sides;

[0037] Figure 4 Schematic diagram of the blade's inlet / outlet edge division;

[0038] Figure 5 A schematic diagram showing the tangent of the arc in each cross section and the feed direction;

[0039] Figure 6 A schematic diagram showing the feed direction of the cathode during synchronous feed processing in each segment;

[0040] The labels in the diagram are as follows: 1. Blade root side guide rail base, 2. Guide rail slider, 3. Blade root side cathode base, 4. Blade root side guide rod, 5. Blade tip side guide rail base, 6. Spindle adapter block, 7. Blade tip side guide rod, 8. Blade tip side cathode base, 9. Upper guide shell of blade tip side cathode, 10. Upper guide shell of blade root side cathode, 11. Lower guide shell of blade tip side cathode, 12. Blade, 13. Lower guide shell of blade root side cathode, 14. Cathode insulating block, 15. Blade root side tool cathode, 16. Blade tip side tool cathode, 17. Blade tip cross-section outline, 18. Segmented synchronous machining dividing surface, 19. Dividing surface cross-section outline, 20. Blade root cross-section outline. Detailed Implementation

[0041] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0042] like Figure 1 and Figure 2As shown, the segmented synchronous feed mechanism includes a blade root side wedge mechanism, a blade tip side wedge mechanism, and a spindle adapter block 6. The two wedge mechanisms mainly include: a blade tip side guide rod 7 and a blade root side guide rod 4 with opposite inclination angles; a blade tip side cathode base 8 and a blade root side cathode base 3 with grooves corresponding to the inclination angles of the guide rods; two sets of guide rail sliders 2 (only one set is shown in the figure); and a blade tip side guide rail base 5 and a blade root side guide rail base 1 with opposite end face inclination angles. During installation, guide rail bases 1 and 5 are fixedly mounted on the machine tool platform. Cathode bases 3 and 8 are mounted on guide rail bases 1 and 5 respectively via guide rail sliders. The blade root side guide rod 4 and the blade tip side guide rod 7 are respectively installed in the grooves on the blade root side cathode base 3 and the blade tip side cathode base 8, forming a wedge mechanism. The bottoms of the blade root side guide rod 4 and the blade tip side guide rod 7 are mounted on the machine tool spindle via the spindle adapter block 6. The inlet / outlet tool cathode includes an inlet / outlet blade root side tool cathode 15 and an inlet / outlet blade tip side tool cathode 16. Each tool cathode comprises a tool cathode body, a cathode insulating block, an upper guide shell with a main liquid inlet, and a lower guide shell with an auxiliary liquid inlet. The upper and lower guide shells and the cathode insulating block are directly mounted on the tool cathode body, eliminating the need for frequent disassembly and assembly during machining. The blade root side inlet / outlet tool cathode 15 and the blade tip side inlet / outlet tool cathode 16 are respectively mounted on the blade root side cathode base 3 and the blade tip side cathode base 8, forming a complete segmented synchronous electrolytic machining device. During machining, the machine tool spindle simultaneously pushes the blade root side guide rod 4 and the blade tip side guide rod 7 to feed horizontally. The pair of wedge mechanisms formed by the blade root side guide rod 4 and the blade tip side guide rod 7 with the blade root side cathode base 3 and the blade tip side cathode base 8 respectively transform the horizontal feed of the guide rods into the feed of the blade root side cathode base 3 and the blade tip side cathode base 8 along the inclination angle of their respective guide rail bases. This, in turn, drives the blade root side inlet / outlet side tool cathode 15 and the blade tip side inlet / outlet side tool cathode 16 to feed synchronously to process the inlet / outlet sides. During machining, the flow field adopts a double-sided liquid inlet counterflow flow field. The electrolyte is divided into four paths, flowing into the machining gap from the main liquid inlet of the blade root side upper guide shell 10 and the blade tip side upper guide shell 9, as well as the auxiliary liquid inlet. It flows through the inlet / outlet sides of the blade blank 12 and flows out freely from the open outlet formed by the blade root side lower guide shell 13, the blade tip side lower guide shell 11, and the blade 14.

[0043] like Figure 4 and Figure 5 As shown, the method for determining the feed direction of the inlet / outlet side tool cathode and the blade inlet / outlet side section includes the following steps:

[0044] Step S1: Extract the blade tip section outline 17 and the blade root section outline 20 from the three-dimensional model of the blade and project them onto the same plane. Draw several inscribed circles in the two section outlines respectively, and fit the center of all inscribed circles to the mid-arc line respectively.

[0045] Step S2: Draw a tangent line to the middle arc at the intersection of the middle arc and the inlet / outlet edge, with the angle bisector of the tangent line between the blade tip section and the blade root section as the reference direction.

[0046] Step S3: The blade section with the tangent direction of the middle arc line in line with the reference direction is taken as the dividing surface 18 of the inlet / outlet side. The angle bisector of the reference direction and the tangent direction of the middle arc line in the blade tip section profile is the feed direction 1 of the tool cathode 16 on the blade tip side of the inlet / outlet side. The angle bisector of the reference direction and the tangent direction of the middle arc line in the blade root section profile is the feed direction 2 of the tool cathode 15 on the blade root side of the inlet / outlet side.

[0047] like Figure 1 and Figure 6 As shown, the method for segmented synchronous electrolytic machining of the inlet / outlet sides of blades with large torsion angles according to the present invention includes the following machining steps:

[0048] Step 1: Install the segmented synchronous feed mechanism on the machine tool, and connect the spindle adapter block 6 to the machine tool spindle; adjust the position of the machine tool spindle to adjust the position of the two segmented tool cathodes so that the two tool cathode profiles form a complete and continuous cathode profile;

[0049] Step 2: Install the blade blank 12 in the fixture, measure and position it and perform tool setting, and maintain the initial machining gap between the blade tip side tool cathode 16, the blade root side tool cathode 15 and the blade blank 12.

[0050] Step 3: The blade blank 12 is connected to the positive terminal of the power supply, and the tool cathode 16 on the blade tip side and the tool cathode 15 on the blade root side are connected to the negative terminal of the power supply. The flow field for processing adopts a double-sided liquid inlet counterflow flow field. The electrolyte is divided into four paths, flowing into the processing gap from the main liquid inlet on the blade tip side, the main liquid inlet on the blade root side, and the auxiliary liquid inlet, respectively. It flows through the inlet / outlet side and flows out freely from the open outlet formed by the lower guide shell 11 on the blade tip side, the lower guide shell 12 on the blade root side, and the blade.

[0051] Step 4: During processing, the machine tool spindle pushes the tip-side guide rod 7 and the root-side guide rod 4 to feed horizontally simultaneously. The wedge mechanism formed by the tip-side guide rod 7 and the tip-side cathode base 8 transforms the horizontal feed of the tip-side guide rod 7 into the feed of the tip-side cathode base 8 along the tilt angle of the tip-side guide rail base 5, thereby driving the tip-side tool cathode 16 closer to the intake / exhaust edge. The wedge mechanism formed by the root-side guide rod 4 and the root-side cathode base 3 transforms the horizontal feed of the root-side guide rod 4 into the feed of the root-side cathode base 3 along the tilt angle of the root-side guide rail base 1, thereby driving the root-side tool cathode 15 closer to the intake / exhaust edge. Under the synchronous movement of the tip-side tool cathode 16 and the root-side tool cathode 15 and the electrochemical dissolution effect, the intake / exhaust edge is formed synchronously.

[0052] Step 5: Turn off the power, electrolyte circulation system, and machine tool.

Claims

1. A method for segmented synchronous electrolytic machining of the intake / exhaust edges of blades with large torsion angles, characterized in that: The blades with large torsion angles are machined in segments simultaneously. The method for determining the segmented cross-section and the feed direction of the tool cathode after segmentation is determined as follows: Step 1. Extract the blade tip section outline (17) and the blade root section outline (20) from the three-dimensional model of the blade and project them onto the same plane; Step 2. Draw several inscribed circles in the projected outlines of the blade tip section contour (17) and the blade root section contour (20); and fit the mid-arc lines through the center of the inscribed circles to form the mid-arc lines of the blade tip section and the mid-arc lines of the blade root section respectively. Step 3. Draw a tangent to the middle arc line at the intersection of the blade tip section and the intake edge, pointing outwards from the section profile. This is called the blade tip section middle arc line intake edge tangent. Draw a tangent to the middle arc line at the intersection of the blade root section and the intake edge, pointing outwards from the section profile. This is called the blade root section middle arc line intake edge tangent. Draw a tangent to the middle arc line at the intersection of the blade tip section and the exhaust edge, pointing outwards from the section profile. This is called the blade tip section middle arc line exhaust edge tangent. Draw a tangent to the middle arc line at the intersection of the blade root section and the exhaust edge, pointing outwards from the section profile. This is called the blade root section middle arc line exhaust edge tangent. Step 4. Using the angle bisector of the tangent of the arc-shaped inlet side in the blade tip section and the tangent of the arc-shaped inlet side in the blade root section as the reference direction, the blade section whose tangent direction is consistent with the reference direction is used as the dividing surface of the inlet side; the angle bisector of the reference direction and the tangent direction of the arc-shaped inlet side in the blade tip section is the feed direction of the tool cathode on the blade tip side of the inlet side, and the angle bisector of the reference direction and the tangent direction of the arc-shaped inlet side in the blade root section is the feed direction of the tool cathode on the blade root side of the inlet side; Using the angle bisector of the tangent of the arc-shaped exhaust edge in the blade tip section and the tangent of the arc-shaped exhaust edge in the blade root section as the reference direction, the blade section with the tangent direction of the arc-shaped exhaust edge aligned with the reference direction is used as the dividing surface of the exhaust edge. The angle bisector of the reference direction and the tangent direction of the arc-shaped exhaust edge in the blade tip section is the feed direction of the tool cathode on the blade tip side of the exhaust edge, and the angle bisector of the reference direction and the tangent direction of the arc-shaped exhaust edge in the blade root section is the feed direction of the tool cathode on the blade root side of the exhaust edge.

2. The method for segmented synchronous electrolytic machining of the inlet / outlet edges of blades with large torsion angles according to claim 1, characterized in that: After segmentation, the intake blade tip side and the intake blade root side are machined simultaneously; or the exhaust blade tip side and the exhaust blade root side are machined simultaneously.

3. An apparatus for implementing the segmented synchronous electrolytic machining method for the inlet / outlet edges of blades with large torsion angles as described in claim 2, characterized in that: It includes a segmented synchronous feed mechanism, a blade root side tool cathode (15), and a blade tip side tool cathode (16); the segmented synchronous feed mechanism consists of a spindle adapter block (6) and a blade root side wedge mechanism and a blade tip side wedge mechanism; The blade root side wedge mechanism consists of a blade root side guide rail base (1), a blade root side cathode base (3), and a blade root side guide rod (4). The blade root side guide rail base (1) is fixedly installed on the machine tool platform, and the blade root side cathode base (3) is installed on the blade root side guide rail base (1) through the corresponding guide rail slider. The blade root side guide rod (4) is installed in the inclined groove of the blade root side cathode base (3) to form a pair of wedge mechanisms. The end face of the blade root side guide rod (4) is installed on the machine tool spindle through the spindle adapter block (6). The blade root side tool cathode (15) is installed on the corresponding blade root side cathode base (3). The angle of the blade root side wedge mechanism is consistent with the feed direction of the intake side blade root side tool cathode or the feed direction of the exhaust side blade root side tool cathode. The blade tip side wedge mechanism consists of a blade tip side guide rail base (5), a blade tip side cathode base (8), and a blade tip side guide rod (7). The blade tip side guide rail base (5) is fixedly installed on the machine tool platform, and the blade tip side cathode base (8) is installed on the blade tip side guide rail base (5) through the corresponding guide rail slider. The blade tip side guide rod (7) is installed in the inclined groove of the blade tip side cathode base (8) to form a pair of wedge mechanisms. The end face of the blade tip side guide rod (7) is installed on the machine tool spindle through the spindle adapter block (6). The blade tip side tool cathode (16) is installed on the corresponding blade tip side cathode base (8). The angle of the blade tip side wedge mechanism is consistent with the feed direction of the intake side blade tip side tool cathode or the feed direction of the exhaust side blade tip side tool cathode.

4. The processing method of the large torsion angle blade inlet / outlet side segmented synchronous electrolysis device as described in claim 3, characterized in that... Includes the following steps: Step 1: Install the segmented synchronous feed mechanism on the machine tool, and connect the spindle adapter block (6) to the machine tool spindle; adjust the position of the machine tool spindle and then adjust the position of the two segmented tool cathodes so that the cathode profiles of the two tools form a complete and continuous cathode profile; Step 2: Install the blade blank (12) in the fixture, measure and position it and perform tool setting, and maintain the initial machining gap between the tip-side tool cathode (16), the root-side tool cathode (15) and the blade blank (12). Step 3: The blade blank (12) is connected to the positive terminal of the power supply, and the tool cathode (16) on the blade tip side and the tool cathode (15) on the blade root side are connected to the negative terminal of the power supply. The flow field for processing adopts a double-sided liquid inlet counterflow flow field. The electrolyte is divided into four paths, flowing into the processing gap from the main liquid inlet on the blade tip side, the main liquid inlet on the blade root side, and the auxiliary liquid inlet, respectively. It flows through the inlet / outlet side and flows out freely from the open outlet formed by the lower guide shell (11) on the blade tip side, the lower guide shell on the blade root side, and the blade. Step 4: During processing, the machine tool spindle pushes the tip-side guide rod (7) and the root-side guide rod (4) to feed horizontally at the same time; the wedge mechanism formed by the tip-side guide rod (7) and the tip-side cathode base (8) transforms the horizontal feed of the tip-side guide rod (7) into the feed of the tip-side cathode base (8) along the tilt angle of the tip-side guide rail base (5), thereby driving the tip-side tool cathode (16) to move closer to the intake / exhaust side; the wedge mechanism formed by the root-side guide rod (4) and the root-side cathode base (3) transforms the horizontal feed of the root-side guide rod (4) into the feed of the root-side cathode base (3) along the tilt angle of the root-side guide rail base (1), thereby driving the root-side tool cathode (15) to move closer to the intake / exhaust side; under the synchronous movement of the tip-side tool cathode (16) and the root-side tool cathode (15) and the electrochemical dissolution effect, the intake / exhaust side is formed synchronously; Step 5: Turn off the power, electrolyte circulation system, and machine tool.

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