Electrolytic finishing device with closed cascade structure and processing method

Abstract

The application provides an electrolytic finishing device with a closed cascade structure and a finishing method. The finishing device comprises a finishing electrode, an electrolyte premixing device and a pressure regulating device. The finishing electrode is arranged on the peripheral side of a first blade, and a finishing area is formed between the finishing electrode and the peripheral side of the first blade. The electrolyte premixing device is used for homogenizing the electrolyte and delivering the electrolyte to the closed cascade structure to form a global integral flow field. The pressure regulating device is used for maintaining the constant pressure of the electrolyte in the global integral flow field. The application eliminates the divergence of the electrolyte from the two blade root parts along the flow path, so that the electrolyte flow field becomes a uniform and stable global integral flow field, and the finishing electrode is in a balanced force state, thereby solving the problems of flow lines at the two blade root parts of the closed cascade structure blade and the difficulty in ensuring the blade machining precision.

Description

Technical Field

[0001] This invention relates to the field of electrolytic machining technology, and more specifically, to an electrolytic machining apparatus and method for a closed-type cascade structure. Background Technology

[0002] In the design of fans and compressors for both military and civilian turbofan aero engines, components such as integral bladed disks and closed rectifiers are widely used. These components are often made of high-temperature alloys and titanium alloys, which have poor machinability. The dense blade cascades, thin and twisted blades, and inclined flow channels, along with the high requirements for blade profile and positional accuracy, make traditional machining extremely difficult. This results in severe machining deformation that is difficult to control, severe tool wear, extremely low machining efficiency, high costs, and poor surface quality.

[0003] Electrolytic machining is a special process that uses the principle of electrochemical anodic dissolution to remove material from metals. It features high machining efficiency, no tool electrode consumption, stress-free machining, and good surface integrity. It is suitable for machining various difficult-to-cut metal materials (titanium alloys, high-temperature heat-resistant alloys, etc.), and is particularly suitable for the batch production of parts with large amounts of material to be efficiently removed, as well as the machining of various complex three-dimensional shapes.

[0004] In electrolytic machining, the tool electrode serves as the electrode, and the workpiece as the anode. Electrolytic machining electrodes are generally made of metal, and the shape of the electrode's working surface is the opposite of the required shape of the workpiece anode. For example, when machining grooves or holes, the end of the tool electrode has a raised rib or columnar structure; when machining bosses, the end of the tool electrode has a concave cavity structure. During electrolytic machining, a certain gap is maintained between the workpiece anode and the tool electrode. A direct current or pulsed voltage is applied between the electrodes. The electrolyte is generally a neutral salt solution, forming an electrochemical reaction cell between the electrodes. Simultaneously, high-speed scouring continuously removes electrolytic machining products and heat, and depolarizes the workpiece. The workpiece anode continuously dissolves according to the shape of the tool electrode until the workpiece's shape and dimensions meet the requirements.

[0005] Electrolytic machining (EMC) can efficiently and precisely process the blade profiles of integral bladed disks and closed rectifiers. Currently, a method using double-sided (blade head and blade back) machining electrodes moving synchronously in opposite directions allows for the simultaneous machining of both the blade head and blade back profiles of a single blade profile. This process is stress-free and causes no mechanical impact on the blades, effectively solving the deformation control problem inherent in mechanical machining. However, due to the small size of the closed blade cascade structure, the distance between two adjacent blades in the smallest cascade is only about 8mm. Considering that approximately 1.5-2mm of allowance is left on the blades during electrolytic finishing, the cascade spacing before finishing is only about 4mm. Furthermore, considering the need for multi-axis linkage along the blade's torsion angle when the machining electrode enters the closed blade cascade, the final machining electrode thickness is approximately 1.5-2mm. Such a thin machining electrode, with its relatively weak rigidity (having a certain overhang length) and the high-speed flow of electrolyte between it and the blade being processed, will inevitably deform, leading to a loss of precision in the machined blade profile.

[0006] Currently, the closed-blade cascade structure of the integrated rectifier is 100 (e.g.) Figure 1 The blade profile machining (as shown) mainly refers to the precision electrolytic machining method of the blade profile of the integral bladed disk, that is, the double-sided (blade basin and blade back) machining electrodes move synchronously towards each other to perform precision forming of the blade basin and blade back profile.

[0007] When electrolytically machining blade profiles, the flow field layout generally includes two types: radial (tip to root) flow and lateral (inlet / exhaust side to exhaust / inlet side) flow. For blades with long airfoils or in a closed cascade structure, only lateral flow can be used for flow field design.

[0008] Due to the space constraints of the closed-blade cascade structure, the electrochemical machining electrode can only be designed as a thin structure with poor rigidity. During electrochemical machining, it deforms under the action of the high-speed flowing electrolyte between it and the blade to be machined, with the electrode tip, especially near the electrolyte outlet, experiencing significant deformation, resulting in a failure to guarantee the accuracy of the blade profile. Because the shape of the closed-blade cascade structure gradually changes during electrochemical machining, the electrochemical flow field also changes continuously, making it difficult to accurately predict the changing pattern of the electrolyte's force on the electrode. To ensure blade profile machining accuracy, the current main method is an iterative approach of "experimentation-blade profile dimension detection-electrode adjustment-experimentation-..." to determine the position and size of the electrode machining profile. This method has a long development cycle, requires numerous repetitions of the experiment, and is further compounded by errors from CNC machining during each electrode adjustment, leading to repeated changes in experimental data and difficulties in process finalization.

[0009] In addition, due to the use of a side-flow flow field, during the electrolytic machining of closed-blade structures, in addition to the electrolyte flowing from the leading (tail) edge to the trailing (tail) edge, a portion of the electrolyte will also flow along the entire process from the two blade roots (e.g.) Figure 2The electrolyte flows out at the inner root (113) and outer root (114) of the blade, causing changes in the flow velocity and uniformity of the electrolyte near the inlet and outlet. Flow lines are also generated at the inner root (113) and outer root (114), resulting in significant differences in the electrolyte state between the center and edge of the flow channel. These problems lead to varying material dissolution efficiencies in different areas of the blade, making it difficult to ensure blade machining precision, and causing flow lines at the two blade roots of closed-cascade blades. Summary of the Invention

[0010] (a) Technical problems to be solved

[0011] The technical problem to be solved by the present invention is that in the existing closed-blade structure, the machining accuracy of the blade is difficult to guarantee due to the influence of the unstable electrolyte flow field during the electrolytic finishing process, and flow lines are easily generated at the two blade roots.

[0012] (II) Technical Solution

[0013] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0014] In a first aspect, the present invention provides an electrolytic finishing apparatus for a closed-blade cascade structure, used for electrolytic finishing of a closed-blade cascade structure placed in an electrolyte. The closed-blade cascade structure has multiple blades, a first cascade channel is formed between a first blade and a second blade, and a second cascade channel is formed between a first blade and a third blade. The finishing apparatus includes a processing electrode, an electrolyte premixing device, and a pressure regulating device. The processing electrode is disposed on the periphery of the first blade, and a processing area is formed between the processing electrode and the periphery of the first blade at intervals. The electrolyte premixing device is used to homogenize the electrolyte and transport the electrolyte to the closed-blade cascade structure, so that the electrolyte flows unidirectionally from one side of the closed-blade cascade structure to the... On the other side of the closed-blade structure, a global flow field is formed. A pressure regulating device is located on the side of the closed-blade structure away from the electrolyte premixing device to maintain a constant electrolyte pressure in the global flow field. The global flow field includes a first flow channel, a second flow channel, and a third flow channel. Electrolyte flows out from the electrolyte premixing device, passes through the first blade channel, and flows to the pressure regulating device to form the first flow channel. Electrolyte flows out from the electrolyte premixing device, passes through the processing area, and flows to the pressure regulating device to form the second flow channel. Electrolyte flows out from the electrolyte premixing device, passes through the second blade channel, and flows to the pressure regulating device to form the third flow channel.

[0015] Preferably, the processing electrode includes a blade back electrode and a blade basin electrode. The blade back electrode has a first processing surface for processing the blade back profile of the first blade, and the blade basin electrode has a second processing surface for processing the blade basin profile of the first blade. The first processing surface and the second processing surface are spaced apart from the periphery of the first blade by a predetermined distance to form the processing area.

[0016] Preferably, the leaf basin electrode is placed in the first leaf cascade channel, and the leaf back electrode is placed in the second leaf cascade channel.

[0017] Preferably, the electrolyte premixing device has multiple partitions, each partition having an outlet, and the outlets on adjacent partitions are staggered.

[0018] Preferably, the electrolyte premixing device has multiple partitions, and each partition has multiple liquid outlets.

[0019] Preferably, the pressure regulating device includes an outlet guide pipe, a baffle plate, and an adjusting component; the length direction of the outlet guide pipe is consistent with the flow direction of the electrolyte, the outlet guide pipe has a first end and a second end, the electrolyte flows through the first flow channel, the second flow channel and the third flow channel to the first end, and flows from the first end to the second end, the second end is connected to an openable baffle plate, and the baffle plate is connected to an adjusting component that can adjust the opening and closing degree threshold of the baffle plate.

[0020] Preferably, the adjusting component is a counterweight connected to the end of the baffle plate; or, the adjusting component is a spring, one end of which is connected to the liquid outlet guide pipe and the other end of which is connected to the baffle plate.

[0021] Secondly, the present invention also provides a processing method, which uses any of the above-described closed-blade cascade structure electrolytic finishing devices to perform electrolytic finishing on the closed-blade cascade structure, the processing method comprising the following steps:

[0022] Step 1: Install the processing electrode on the periphery of the first blade, connect the processing electrode to the negative terminal of the power supply, and connect the closed blade cascade structure to the positive terminal of the power supply.

[0023] Step 2: The electrolyte is introduced into the electrolyte premixing device, which homogenizes the electrolyte and delivers it to the closed blade structure, so that the electrolyte flows unidirectionally from one side of the closed blade structure to the other side, forming a global flow field.

[0024] Step 3: Adjust the pressure control device to keep the electrolyte pressure in the global flow field constant;

[0025] Step 4: The electrolyte flows in the second flow channel to perform electrolytic finishing on the first blade.

[0026] Preferably, the electrolyte is a NaNO3 electrolyte, the pressure range of the electrolyte is 0.2MPa-0.8MPa, and the temperature range of the electrolyte is 25℃-40℃.

[0027] Preferably, the voltage range of the power supply is 18V-24V, the pulse width is t = 0.1ms-0.3ms, and the pulse duty cycle is 5%-60%.

[0028] (III) Beneficial Effects

[0029] The above-described technical solution of the present invention has at least the following advantages:

[0030] 1. The closed-type blade cascade structure is placed in the electrolyte, and the first, second, and third flow channels constitute a global overall flow field. The electrolyte flow direction in the global overall flow field is consistent, that is, it flows from the leading (tail) edge of the blade to the trailing (tail) edge of the blade, which eliminates the divergence of electrolyte along the flow from the two blade roots and solves the problem of flow lines generated at the two blade roots of the closed-type blade cascade structure.

[0031] 2. A first flow channel is formed between the side of the blade basin electrode facing away from the second machining surface and the second blade; a third flow channel is formed between the side of the blade back electrode facing away from the first machining surface and the third blade. Since the first and second flow channels are located on opposite sides of the blade basin electrode, and the pressure of the electrolyte flowing through the first flow channel is approximately equal to the pressure of the electrolyte flowing through the second flow channel, the pressure on both sides of the blade basin electrode is basically balanced. Similarly, since the third flow channel is located on opposite sides of the blade back electrode, and the pressure of the electrolyte flowing through the third flow channel is approximately equal to the pressure of the electrolyte flowing through the second flow channel, the pressure on both sides of the blade back electrode is basically balanced. By adopting the above technical solution, the generation of large unilateral pressure on the blade back electrode and blade basin electrode by the electrolyte is avoided, ensuring that the blade back electrode and blade basin electrode do not undergo elastic deformation. This solves the problem of difficulty in ensuring blade machining accuracy due to deformation of the weakly rigid blade back electrode and blade basin electrode under electrolyte pressure.

[0032] 3. The present invention has an electrolyte premixing zone upstream of the overall flow field. The electrolyte premixing zone can homogenize the electrolyte flow field flowing into the processing area to eliminate eddies and cavitation caused by shock waves at the inlet, improve the stability of the flow state in the inlet section, and avoid problems such as poor surface quality and precision caused by chaotic electrolyte flow state and processing electrode vibration.

[0033] 4. In this invention, a liquid outlet guide pipe is set downstream of the global flow field, which delays the setting of the area with a large electrolyte pressure attenuation rate in the global flow field, so that the area with a large pressure attenuation is far away from the processing area, thereby reducing the change of electrolyte pressure gradient in the processing area and avoiding the vibration of the processing electrode caused by drastic pressure changes.

[0034] 5. A pressure control device is installed downstream of the overall flow field. The tension threshold of the baffle plate can be adjusted by changing the specifications of the adjustment components, thereby regulating the electrolyte pressure, flow rate and velocity, and realizing the spatiotemporal control of the overall flow field. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 This is a schematic diagram of a closed cascade structure.

[0037] Figure 2 This is a magnified view of a closed cascade structure.

[0038] Figure 3 This is a schematic diagram of the closed-type cascade structure electrolytic finishing device provided in an embodiment of the present invention.

[0039] Figure 4 yes Figure 3 Sectional view at point AA.

[0040] Figure 5 This is a schematic diagram of the pressure regulation device provided in an embodiment of the present invention.

[0041] Figure 6 It is a graph showing the relationship between the electrolyte flow distance and the electrolyte pressure.

[0042] The labels for the attached figures are as follows:

[0043] 100. Closed blade cascade structure; 110. First blade; 111. Blade back profile; 112. Blade basin profile; 113. Inner root of blade; 114. Outer root of blade; 120. Second blade; 130. First blade cascade channel; 140. Third blade; 150. Second blade cascade channel; 1. Processing electrode; 2. Electrolyte premixing device; 3. Pressure regulating device; 4. Processing area; 5. First flow channel; 6. Second flow channel; 7. Third flow channel; 11. Blade back electrode; 1101. First processing surface; 12. Blade basin electrode; 121. Second processing surface; 21. Baffle; 211. Liquid outlet; 22. Liquid inlet; 31. Liquid outlet guide pipe; 311. First end; 312. Second end; 32. Water baffle; 33. Adjustment component. Detailed Implementation

[0044] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0045] It should be noted that when a component is referred to as "fixed to" or "set on" another component, it can be located directly on or indirectly on the other component. When a component is referred to as "connected to" another component, it can be directly or indirectly connected to the other component.

[0046] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do not indicate that the device or element must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0047] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating relative importance or the number of technical features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified. The specific implementation of this invention will be described in more detail below with reference to specific embodiments:

[0048] like Figure 3As shown, this embodiment of the invention provides an electrolytic finishing apparatus for a closed-blade cascade structure 100 placed in an electrolyte. The closed-blade cascade structure 100 has multiple blades. A first cascade channel 130 is formed between the first blade 110 and the second blade 120, and a second cascade channel 150 is formed between the first blade 110 and the third blade 140. The finishing apparatus includes a processing electrode 1, an electrolyte premixing device 2, and a pressure regulating device 3. The processing electrode 1 is disposed on the periphery of the first blade 110, and a processing area 4 is formed between the processing electrode 1 and the periphery of the first blade 110. The electrolyte premixing device 2 is used to homogenize the electrolyte and transport the electrolyte to the closed-blade cascade structure 100 to facilitate electrolysis. The electrolyte flows unidirectionally from one side of the closed blade structure 100 to the other side, forming a global flow field. The pressure regulating device 3 is located on the side of the closed blade structure 100 away from the electrolyte premixing device 2 to maintain a constant electrolyte pressure in the global flow field. The global flow field includes a first flow channel 5, a second flow channel 6, and a third flow channel 7. The electrolyte flows out from the electrolyte premixing device 2, passes through the first blade channel 130, and flows to the pressure regulating device 3 to form the first flow channel 5. The electrolyte flows out from the electrolyte premixing device 2, passes through the processing area 4, and flows to the pressure regulating device 3 to form the second flow channel 6. The electrolyte flows out from the electrolyte premixing device 2, passes through the second blade channel 150, and flows to the pressure regulating device 3 to form the third flow channel 7. It should be noted that the homogenization treatment in this embodiment of the invention refers to the following: when the electrolyte passes through the electrolyte premixing device 2, it can reduce the velocity difference of the electrolyte flowing along the first flow channel 5, the second flow channel 6, and the third flow channel 7, so that the flow velocity of the electrolyte flowing through the first flow channel 5, the second flow channel 6, and the third flow channel 7 is basically the same, thereby homogenizing the flow velocity of the electrolyte in the overall flow field and making the flow velocity of the electrolyte in the overall flow field tend to be stable. Specifically, the electrolyte premixing device 2 is provided with an inlet 22, and the electrolyte flows into the electrolyte premixing device 2 through the inlet 22. Further, the closed blade cascade structure 100 is placed in the electrolyte, and the first flow channel 5, the second flow channel 6, and the third flow channel 7 constitute the overall flow field. The electrolyte flow direction in the overall flow field is consistent, that is, it flows from the leading (tail) edge of the blade to the trailing (leading) edge of the blade, eliminating the electrolyte flow from the two blade roots (e.g., Figure 2 The divergence phenomenon at the inner root 113 and outer root 114 of the blade shown is used to solve the problem of flow lines at the two roots of the blade in the closed blade cascade structure 100.

[0049] In one embodiment, the processing electrode 1 includes a blade back electrode 11 and a blade base electrode 12. The blade back electrode 11 has a first processing surface 1101 for processing the blade back profile 111 of the first blade 110, and the blade base electrode 12 has a second processing surface 121 for processing the blade base profile 112 of the first blade 110. The first processing surface 1101 and the second processing surface 121 are spaced apart from the periphery of the first blade 110 by a predetermined distance to form a processing area 4. Specifically, the shape of the first processing surface 1101 matches the shape of the blade back profile 111, and the shape of the second processing surface 121 matches the shape of the blade base profile 112.

[0050] In one embodiment, the blade basin electrode 12 is placed within the first blade channel 130, and the blade back electrode 11 is placed within the second blade channel 150. Electrolyte flows out from the electrolyte premixing device 2, passes through the processing area 4, and flows to the pressure regulating device 3 to form a second flow channel 6, i.e., a second flow channel 6 is formed between the first processing surface 1101, the second processing surface 121, and the periphery of the first blade 110; electrolyte flows out from the electrolyte premixing device 2, passes through the first blade channel 130, and flows to the pressure regulating device 3 to form a first flow channel 5, i.e., a first flow channel 5 is formed between the side of the blade basin electrode 12 facing away from the second processing surface 121 and the second blade 120; electrolyte flows out from the electrolyte premixing device 2, passes through the second blade channel 150, and flows to the pressure regulating device 3 to form a third flow channel 7, i.e., a third flow channel is formed between the side of the blade back electrode 11 facing away from the first processing surface 1101 and the third blade 140. Since the first flow channel 5 and the second flow channel 6 are located on both sides of the blade basin electrode 12, and the pressure of the electrolyte flowing through the first flow channel 5 is approximately equal to the pressure of the electrolyte flowing through the second flow channel 6, the pressure on both sides of the blade basin electrode 12 is basically balanced. This avoids the electrolyte exerting a large unilateral pressure on the blade basin electrode 12, ensuring that the blade basin electrode 12 will not undergo elastic deformation. This solves the problem of the weakly rigid blade basin electrode 12 deforming under electrolyte pressure, which makes it difficult to ensure the blade's machining accuracy. Similarly, since the third flow channel 7 and the second flow channel 6 are located on both sides of the blade back electrode 11, and the pressure of the electrolyte flowing through the third flow channel 7 is approximately equal to the pressure of the electrolyte flowing through the second flow channel 6, the pressure on both sides of the blade back electrode 11 is basically balanced. This avoids the electrolyte exerting a large unilateral pressure on the blade back electrode 11, ensuring that the blade back electrode 11 will not undergo elastic deformation. This solves the problem of the weakly rigid blade back electrode 11 deforming under electrolyte pressure, which makes it difficult to ensure the blade's machining accuracy.

[0051] like Figure 4 As shown, in one embodiment, the electrolyte premixing device 2 has multiple partitions 21, and the partitions 21 are provided with liquid outlets 211, with the liquid outlets 211 on adjacent partitions 21 being staggered.

[0052] In one embodiment, the electrolyte premixing device 2 has multiple partitions 21, each partition 21 having multiple outlets 211. When the electrolyte flows into the closed blade structure 100, shock waves are easily generated, which can easily cause eddies and cavitation in the overall flow field. The electrolyte premixing device 2 can improve the stability of the flow state in the inlet section, homogenize the electrolyte flow field flowing into the processing area 4, and avoid problems such as chaotic electrolyte flow and poor surface quality and precision caused by the vibration of the processing electrode 1.

[0053] like Figure 5 As shown, in one embodiment, the pressure regulating device 3 includes an outlet guide pipe 31, a baffle plate 32, and an adjusting component 33. The length direction of the outlet guide pipe 31 is consistent with the flow direction of the electrolyte. The outlet guide pipe 31 has a first end 311 and a second end 312. The electrolyte flows through a first flow channel 5, a second flow channel 6, and a third flow channel 7 to the first end 311 and from the first end 311 to the second end 312. An openable baffle plate 32 is connected to the second end 312, and an adjusting component 33 is connected to the baffle plate 32 to adjust the opening and closing degree threshold of the baffle plate 32. Figure 6 As shown, it is easy to see that the electrolyte pressure gradually decreases as the electrolyte flow distance increases. In the initial stage of electrolyte flow, there is a stable region where the electrolyte pressure is basically stable, and in the final stage, there is a decay region where the electrolyte pressure drops rapidly. If the decay region is located within the processing area 4, the drastic changes in electrolyte pressure will cause the processing electrode 1 to vibrate, thus affecting the accuracy of the processing electrode 1 in electrolytic machining of the closed-type cascade structure 100. This embodiment of the invention provides an outlet guide pipe 31, allowing the electrolyte to flow backward a certain distance along the length of the outlet guide pipe 31. This delays the location of areas with large electrolyte pressure decay rates in the overall flow field, keeping these areas away from the processing area 4, reducing the electrolyte pressure gradient change in the processing area 4, and preventing drastic pressure changes from causing vibration in the processing electrode 1.

[0054] In one embodiment, the adjusting component 33 is a weight connected to the end of the baffle plate 32; specifically, the weight of the weight is preferably 0.5kg-2kg. The weight has a certain weight and is connected to the end of the baffle plate 32. The baffle plate 32 is positioned perpendicular to the flow direction of the electrolyte. When the electrolyte flows past the baffle plate 32, it needs to overcome the gravity of the baffle plate 32. The greater the gravity of the baffle plate 32, the more difficult it is for the electrolyte to push the baffle plate 32 open (i.e., the greater the opening force), thereby increasing the electrolyte pressure on the side of the baffle plate 32 closer to the outlet guide pipe 31. By adjusting the weight of the weight, the threshold of the opening force provided by the baffle plate 32 can be adjusted, thereby regulating the electrolyte pressure. In another embodiment, the adjusting component 33 is a spring, one end of which is connected to the outlet guide pipe 31, and the other end of which is connected to the baffle plate 32. Similarly, by adjusting the spring constant, the threshold of the tension force provided by the baffle plate 32 can be adjusted, thereby regulating the electrolytic hydraulic pressure. Furthermore, the flow rate and velocity of the electrolyte can also be adjusted.

[0055] Secondly, the present invention also provides a processing method, wherein the closed blade cascade structure 100 is electrolytically precision machined using any of the above-mentioned technical solutions, and the processing method includes the following steps:

[0056] Step 1: Install the processing electrode 1 on the periphery of the first blade 110, connect the processing electrode 1 to the negative terminal of the power supply, and connect the closed blade cascade structure 100 to the positive terminal of the power supply.

[0057] Step 2: The electrolyte is introduced into the electrolyte premixing device 2, which homogenizes the electrolyte and transports it to the closed blade structure 100 so that the electrolyte flows unidirectionally from one side of the closed blade structure 100 to the other side, forming a global flow field.

[0058] Step 3: Adjust the pressure control device 3 to keep the electrolyte pressure constant in the overall flow field.

[0059] Step 4: The electrolyte flows in the second flow channel 6 to perform electrolytic finishing on the first blade 110. During electrolytic machining, a certain gap is maintained between the closed blade cascade structure 100 and the machining electrode 1. A DC or pulsed voltage is applied between the electrodes. The electrolyte is generally a neutral salt solution, forming an electrochemical reaction cell between the electrodes. At the same time, high-speed scouring continuously removes the electrolytic machining products and heat, and depolarizes the surface. The blades on the closed blade cascade structure 100 continuously dissolve according to the shape of the machining electrode 1 until the shape and size of the blades meet the requirements.

[0060] In one embodiment, the electrolyte is NaNO3 electrolyte, with a pressure range of 0.2 MPa-0.8 MPa and a temperature range of 25°C-40°C. NaNO3 electrolyte is a nonlinear electrolyte with high processing efficiency and low cost. It allows for the removal of small gaps due to its small cutting gap. Experiments have shown that the electrolyte in this embodiment preferably contains 10%-20% NaNO3. Excessive electrolyte pressure can cause excessive local erosion, resulting in uneven wall thickness; insufficient pressure will not meet the erosion conditions required for electrolytic processing. Experiments have determined that the electrolyte pressure range in this embodiment is controlled between 0.2 MPa and 0.8 MPa. The electrolyte temperature needs to remain stable during processing to ensure consistent processing conditions during batch processing. Based on experiments, the electrolyte temperature range in this embodiment is preferably 25°C-40°C.

[0061] In one embodiment, the power supply voltage range is 18V-24V, the pulse width t = 0.1ms-0.3ms, and the pulse duty cycle is 5%-60%. Higher voltage helps improve processing efficiency. Experiments have determined that the processing voltage for stainless steel and typical high-temperature alloys is set at 18V-24V.

[0062] In one embodiment, the processing electrode 1 is connected to a driving device, and the feed speed of the processing electrode 1 driven by the driving device is preferably 0.05 mm / min to 0.5 mm / min. The processing gap of the processing area 4 should be appropriately increased to weaken the concentrated etching effect and make the removal more uniform. However, it must be controlled within the anodic dissolution cut-off gap. Experiments have determined that the initial processing gap is 0.1 mm to 0.3 mm.

[0063] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An electrolytic finishing apparatus for a closed-blade cascade structure, used for electrolytic finishing of a closed-blade cascade structure placed in an electrolyte, the closed-blade cascade structure having multiple blades, a first cascade channel forming between a first blade and a second blade, a second cascade channel forming between a first blade and a third blade, the second blade and the third blade being located on opposite sides of the first blade, characterized in that, The finishing apparatus includes: A processing electrode is disposed on the periphery of the first blade, and a processing area is formed between the processing electrode and the periphery of the first blade at a distance. An electrolyte premixing device is used to homogenize the electrolyte and transport the electrolyte to the closed-loop cascade structure, so that the electrolyte flows unidirectionally from one side of the closed-loop cascade structure to the other side of the closed-loop cascade structure, forming a global flow field. A pressure regulating device is located on the side of the closed-type cascade structure away from the electrolyte premixing device, used to maintain a constant electrolyte pressure in the global flow field. The overall flow field includes a first flow channel, a second flow channel, and a third flow channel. The electrolyte flows out from the electrolyte premixing device, passes through the first blade channel, and flows to the pressure regulating device to form the first flow channel. The electrolyte flows out from the electrolyte premixing device, passes through the processing area, and flows to the pressure regulating device to form the second flow channel. The electrolyte flows out from the electrolyte premixing device, passes through the second blade channel, and flows to the pressure regulating device to form the third flow channel.

2. The closed-type blade cascade structure electrolytic finishing apparatus as described in claim 1, characterized in that, The processing electrode includes a blade back electrode and a blade basin electrode. The blade back electrode has a first processing surface for processing the blade back profile of the first blade, and the blade basin electrode has a second processing surface for processing the blade basin profile of the first blade. The first processing surface and the second processing surface are spaced apart from the periphery of the first blade by a predetermined distance to form the processing area.

3. The closed-type blade cascade structure electrolytic finishing apparatus as described in claim 2, characterized in that, The leaf basin electrode is placed in the first leaf cascade channel, and the leaf back electrode is placed in the second leaf cascade channel.

4. The closed-type blade cascade structure electrolytic finishing apparatus as described in claim 1, characterized in that, The electrolyte premixing device has multiple partitions, each with an outlet, and the outlets on adjacent partitions are staggered.

5. The closed-type blade cascade structure electrolytic finishing apparatus as described in claim 1, characterized in that, The electrolyte premixing device has multiple layers of partitions, and each layer of partitions has multiple liquid outlets.

6. The closed-type blade cascade structure electrolytic finishing apparatus as described in claim 1, characterized in that, The pressure regulating device includes an outlet guide pipe, a baffle plate, and an adjusting component. The length direction of the outlet guide pipe is consistent with the flow direction of the electrolyte. The outlet guide pipe has a first end and a second end. The electrolyte flows through the first flow channel, the second flow channel, and the third flow channel to the first end and from the first end to the second end. An openable baffle plate is connected to the second end. The baffle plate is connected to an adjusting component that can adjust the opening and closing degree threshold of the baffle plate.

7. The closed-type blade cascade structure electrolytic finishing apparatus as described in claim 6, characterized in that, The adjusting component is a counterweight connected to the end of the baffle plate; or, the adjusting component is a spring, one end of which is connected to the liquid outlet guide pipe and the other end of which is connected to the baffle plate.

8. A processing method, comprising electrolytic finishing of a closed-blade cascade structure using the electrolytic finishing apparatus for closed-blade cascade structures as described in any one of claims 1-7, characterized in that, The processing method includes the following steps: Step 1: Install the processing electrode on the periphery of the first blade, connect the processing electrode to the negative terminal of the power supply, and connect the closed blade cascade structure to the positive terminal of the power supply. Step 2: The electrolyte is introduced into the electrolyte premixing device, which homogenizes the electrolyte and delivers it to the closed blade structure, so that the electrolyte flows unidirectionally from one side of the closed blade structure to the other side, forming a global flow field. Step 3: Adjust the pressure control device to keep the electrolyte pressure in the global flow field constant; Step 4: The electrolyte flows in the second flow channel to perform electrolytic finishing on the first blade.

9. The processing method as described in claim 8, characterized in that, The electrolyte is NaNO3 electrolyte, the pressure range of the electrolyte is 0.2MPa-0.8MPa, and the temperature range of the electrolyte is 25℃-40℃.

10. The processing method as described in claim 8, characterized in that, The power supply has a voltage range of 18V-24V, a pulse width of t=0.1ms-0.3ms, and a pulse duty cycle of 5%-60%.

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