Combined sleeve type cathode and integral blisk rough-finish integrated electrolytic machining method

Abstract

This invention relates to a combined sleeve-type cathode and an integrated roughing and finishing electrolytic machining method for an integral bladed disk. The method is characterized by the following: the combined sleeve-type cathode includes a front end-face sleeve-type cathode and two side blade basin and blade back profile cathodes. Each cathode is insulated from the others and independently powered. The energizing state of each cathode depends on the feed direction of the combined cathode. During machining, the front end-face sleeve-type cathode is energized first, while the blade basin / blade back profile cathodes are de-energized. The combined sleeve-type cathode feeds radially along the integral bladed disk to complete the roughing of the blade. Subsequently, the blade basin or blade back profile cathodes are energized, while the other cathodes are de-energized. The combined sleeve-type cathode feeds along the normal direction of the blade basin or blade back to complete the finishing of the blade basin or blade back. This method employs an integrated tool cathode structure, allowing for integrated roughing and finishing of the integral bladed disk in a single clamping and machining operation. This ensures positioning accuracy, simplifies the design of the tool cathode and fixtures, and improves machining efficiency and accuracy.

Description

Technical Field

[0001] This invention relates to an integrated roughing and finishing electrolytic machining method for a combined sleeve-type cathode and an integral bladed disk, belonging to the field of electrolytic machining technology. Background Technology

[0002] Integral bladed disks (IBDs) are a crucial component of modern aero-engines. They integrate the blades and the disk into a single unit, resulting in a significant reduction in the number of engine parts, substantial weight reduction, and marked improvements in reliability and aerodynamic performance. However, because IBDs often utilize difficult-to-machine materials such as nickel-based high-temperature alloys, and because the blades possess complex structural features including spatial bending and torsion characteristics and varying cross-sectional profiles, efficient and precise manufacturing of IBDs is extremely challenging.

[0003] Electrolytic machining (EMC) is a specialized machining technology that removes material from workpieces based on the principle of electrochemical anodic dissolution. Compared to traditional machining techniques, EMC is a non-contact cold working process with advantages such as no tool wear, high machining efficiency, good surface quality, and no limitations imposed by the hardness and strength of the anode material itself. It is ideally suited for the efficient machining of complex-shaped components made from difficult-to-machine materials. EMC offers high machining efficiency and low cost in the mass production of high-strength and high-hardness materials such as high-temperature alloys and titanium alloys, and is widely used in the defense industry and aerospace manufacturing.

[0004] Currently, the overall bladed disk electrochemical machining process generally consists of two steps: pre-machining of the blade cascade channel and finishing of the blade profile. Pre-machining of the blade cascade channel, as the first step, primarily aims to remove most of the material from the workpiece blank and produce a blade blank with a certain allowance and precision. Finishing of the blade profile, as the second step, primarily aims to further remove the remaining material from the blade blank to achieve the desired machining accuracy.

[0005] Nesting electrochemical machining is an electrochemical machining method that removes excess material around the ideal surface of a workpiece by using a shaped cathode. In nesting electrochemical machining, based on the pre-machined part shape and the electrochemical side corrosion gap, an inner cavity is machined into a metal sheet. This hollow metal sheet serves as the tool cathode, and the edge of the inner cavity acts as the cathode machining edge. The part is shaped by the side of the cathode machining edge. During machining, the positive and negative terminals of the power supply are connected to the workpiece and the tool cathode, respectively. The workpiece and the tool cathode move relative to each other along a given feed trajectory. The electrolyte flows at high speed in the machining gap, removing the workpiece material directly opposite the cathode end face, while retaining the workpiece material corresponding to the cathode machining edge, ultimately forming a complex part. Because it can shape the workpiece contour in a single machining operation and has high material removal efficiency, nesting electrochemical machining has become one of the mainstream processes for rough machining of integral bladed disk blades.

[0006] Although nesting electrolytic machining has many advantages, the cathode used in this method is only a sleeve-shaped cathode with an end face that is rough-machined to the workpiece contour. Therefore, further finishing of the workpiece is still required after the nesting process. In previous machining methods, the finishing cathode was usually redesigned based on the blade profile, and a new set of tooling fixtures was designed according to the designed cathode and the workpiece's movement process. Alternatively, traditional machining processes were used to finish the workpiece after the roughing process of nesting electrolytic machining. These traditional methods require secondary clamping of the workpiece and redesign of the finishing scheme, presenting several problems that need to be solved.

[0007] In the patent "Pulse Electrolysis One-Step Nesting Processing Device and Method for Blades and Their Surface Microtextures" (Application No. 202210695493.X, Applicant: Changchun University of Technology, Inventors: Ren Wanfei, Xu Jinkai, Tao Jin, Yu Huadong, Wang Manfei), a combination of cathode sheet and cathode body is used to process the profile of blades with equal cross-sections and to manufacture the microtextures on the leading and trailing edges of the blades. The same electrolysis equipment is used to achieve in-situ manufacturing of both the blade processing and the microtextures on the blade surface. In contrast, this patent uses a combined nesting cathode, which can achieve integrated roughing and finishing of the entire bladed disk. Furthermore, the combined nesting cathode has a simple, compact, and sophisticated structure, and after installation, it can move under the CNC system of a machine tool without the need for additional drive devices.

[0008] In the patent "An Integral Impeller Electrolytic Sleeve and Forming Processing Device" (application number 202022635196.5, applicant Changzhou Xinjiang Intelligent Equipment Co., Ltd., inventors Xia Renbo, Xu Bo, Xia Jianbo), a sleeve-shaped cathode for rough machining of the integral impeller disk and a plate-shaped cathode for fine machining of the blade profile are installed on the same machine tool. The impeller disk blank can complete rough and fine machining in one clamping, reducing repeated positioning errors. In comparison, this patent adopts a combined sleeve-shaped cathode with an integrated structure. Only one set of cathodes and one set of tooling fixtures are needed to complete the integrated rough and fine machining of the integral impeller disk in one processing step. It is convenient to operate, has high processing efficiency, and low manufacturing cost.

[0009] In the patent "Method for Electrolytic Machining of Integral Bladed Disks with Double-Sided Combination and Dual-Cathode and Zoned Electrostatic Control" (Application No. 202210306217.X, Applicant: Nanjing University of Aeronautics and Astronautics, Inventors: Xu Zhengyang, Shen Zhenyu, Liu Jia, Zhu Dong), a method using double-sided combined dual-tool cathodes for simultaneous feeding is employed to perform step-by-step electrolytic machining of the blade cascade channels and blade profiles of the integral bladed disk, thereby improving machining efficiency. In contrast, this patent uses only a single combined sleeve-type cathode to achieve integrated roughing and finishing machining of the integral bladed disk. The cathode structure design and motion are simple, the manufacturing cost is low, the operation is convenient, and the feasibility is strong.

[0010] In the patent "An Electrolytic Machining Method for an Integral Bladed Disk" (application number 201811128151.X, applicant: China Aviation Manufacturing Technology Research Institute, inventors: Huang Mingtao, Zhang Mingqi, Cheng Xiaoyuan, Fu Junying), a cathode head including a blade basin profile cathode and a blade back profile cathode is used. First, the machining tool is driven to feed radially along the integral bladed disk blank, electrolytically pre-machining the blade cascade channels between the blades. Then, the integral bladed disk blank is driven to rotate clockwise / counterclockwise around its central axis for finishing of the blade basin / blade back profiles. In contrast, the method used in this invention belongs to the category of sleeve-type electrolytic machining. The proposed combined sleeve-type cathode and machining method can machine a blade shape with a certain allowance in one step. Then, the blade profile can be finished through the simple linear motion of the combined sleeve-type cathode. The tool cathode structure is simple and has a wide range of applications.

[0011] Analysis shows that in order to shorten the processing cycle, simplify the cathode design steps, and improve processing efficiency, there is an urgent need for a new electrolytic machining tool cathode structure and process method to achieve integrated rough and fine manufacturing of integral bladed disks. Summary of the Invention

[0012] Purpose of the invention: The purpose of this invention is to simplify the cathode design steps for electrolytic machining of integral bladed disks, improve machining efficiency, shorten machining cycle, reduce clamping and positioning errors, and ensure machining accuracy. It proposes a combined sleeve-type cathode and an integrated rough and fine electrolytic machining method for integral bladed disks.

[0013] A combined sleeve-type cathode, characterized in that it comprises an insulating plate, an insulating base, an end-face sleeve-type cathode, a blade-bowl-shaped surface cathode, and a blade-back-shaped surface cathode; the end-face sleeve-type cathode is a hollow structure, with the end-face sleeve-type cathode located on the front side of the insulating plate and the insulating base located on the rear side of the insulating plate, while the blade-bowl-shaped surface cathode and the blade-back-shaped surface cathode are located on opposite sides of the insulating plate; the three cathodes, end-face sleeve-type cathode, blade-bowl-shaped surface cathode, and blade-back-shaped surface cathode, are insulated from each other and are each connected to its own lead post, which passes through the insulating base and is connected to a zoned power control device.

[0014] The integrated roughing and finishing electrolytic machining method for the composite sleeve cathode integral impeller is characterized by the following steps: Step 1: The integral impeller is mounted on an indexing rotary table, and the composite sleeve cathode is mounted on the machine tool spindle. The integral impeller is rotated using the machine tool indexing rotary table so that the position of the first blade to be machined on the integral impeller is aligned with the initial position of the composite sleeve cathode, maintaining a certain initial machining gap between them; Step 2: The integral impeller blank is connected to the positive terminal of the power supply, and the composite sleeve cathode is connected to the negative terminal of the power supply through a zoned power control device. The electrolyte supply is turned on. Liquid system; Step 3: Perform rough machining of the first blade of the integral bladed disk; The machine tool spindle drives the combined sleeve cathode to feed radially along the integral bladed disk, that is, to move along the X-axis slide. The zone control device simultaneously and sensitively identifies the motion state and supplies power only to the end face sleeve cathode. The rough machining of the blade profile is completed through the end face sleeve cathode, and a blade blank with a certain allowance is initially machined; Step 4: Perform blade profile finishing; The combined sleeve cathode is in the same working position as after the rough machining in Step 3. The machine tool spindle drives the combined sleeve cathode from the original The radial feed is converted into movement along the normal direction of the blade's facet or back profile, i.e., movement along the Y-axis slide. The zoned power control device de-energizes the end face sleeve cathode, supplying power only to the blade facet or back profile cathode for finishing the blade facet or back profile. After the blade facet or back profile machining is completed, the machine tool drives the combined sleeve cathode to move along the normal direction of the blade back or blade facet. The zoned power control device de-energizes the blade facet or back profile cathode, supplying power only to the back profile or blade facet cathode for finishing the blade back or blade facet. This completes the finishing of the blade back or blade facet in one machining cycle. Step 5: After the first blade in Step 4 is machined, the combined sleeve cathode returns to the initial machining position. The indexing turntable is driven to rotate the entire bladed disk blank around the center of the blank by an angle of 360° / N degrees, where N is the number of blades, so that it is exactly in the machining position of the second blade. The second blade is then machined in a rough and finish manner. The above machining steps are repeated to complete the rough and finish machining of all blades of the entire bladed disk in sequence. Step 6: The power supply and electrolyte supply system are turned off.

[0015] Beneficial effects: Compared with the prior art, the present invention has the following significant features.

[0016] (1) A combined sleeve cathode structure is provided. The combined sleeve cathode is an integral structure, with the end face sleeve cathode located on the front side of the combined cathode, and the other two face cathodes located on both sides of the combined cathode and behind the end face sleeve cathode. The three cathodes are insulated from each other by an insulating plate and are independently energized. The structure is simple, lightweight, easy to manufacture, and convenient to install and operate.

[0017] (2) A method for integrated roughing and finishing of an integral bladed disk using a combined sleeve cathode within the same machining cycle is provided. During machining, the front end face sleeve cathode is energized first, while the blade basin / blade back profile cathode is de-energized. The combined sleeve cathode is fed radially along the integral bladed disk to complete the roughing of the blade. Subsequently, the blade basin or blade back profile cathode is energized, while the other cathodes are de-energized. The combined sleeve cathode is fed along the normal direction of the blade basin or blade back to complete the finishing of the blade basin or blade back. This method uses a combined sleeve cathode, and the integrated roughing and finishing of the integral bladed disk can be completed in one clamping and one machining operation, ensuring positioning accuracy and improving machining efficiency and accuracy.

[0018] (3) The combined sleeve cathode and integral bladed disk roughing and finishing electrolytic machining method has a wide range of applications. Because the combined sleeve tool cathode has a simple and exquisite structure, the process is easy to operate, and the movement is simple, it has a wide range of applications. It is not only suitable for the roughing and finishing of outward integral bladed disk blades, but also for the roughing and finishing of single blades and inward integral bladed disk blades. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the assembly method for the integrated roughing and finishing of an integral bladed disk using a combined sleeve-type cathode in this invention.

[0020] Figure 2 This is a schematic diagram of the assembly of the combined sleeve-type cathode structure in this invention;

[0021] Figure 3 This is an exploded view of a combined sleeve-type cathode structure;

[0022] Figure 4 , Figure 5 , Figure 6 , Figure 7 This is a schematic diagram illustrating the machining process of the integral bladed disk using a combined sleeve-type cathode in this invention. Figure 4 This is a schematic diagram of the initial processing state. Figure 5 This is a schematic diagram of the state at a certain moment in the roughing process. Figure 6 This is a schematic diagram of the profile of the blade back (or leaf basin) for precision machining. Figure 7 for Figure 6 A magnified view of a portion of the processing area.

[0023] In the figure: 1. Combined sleeve cathode (101, end face sleeve cathode; 102, end face sleeve cathode lead post; 103, blade basin-shaped cathode; 104, blade basin-shaped cathode lead post; 105, blade back-shaped cathode; 106, blade back-shaped cathode lead post; 107, insulating plate; 108, insulating base); 2. Zoned power control device; 3. Cathode rod; 4. Integral blade disk; 5. Machine tool body (501, X-axis slide; 502, Y-axis slide; 503, Z-axis slide; 504, indexing rotary table; 505, machine tool platform). Detailed Implementation

[0024] The present invention will now be further described with reference to the accompanying drawings.

[0025] The electrolytic machining process of the workpiece using the "Combined Sleeve-Type Cathode and Integral Bladed Disk Rough and Finish Electrolytic Machining Method" of this invention includes the following steps:

[0026] Step 1: Install the integral bladed disk 4 on the indexing turntable 504, install the combined sleeve cathode 1 on the machine tool Z-axis slide 503, rotate the integral bladed disk 4 through the machine tool indexing turntable 504 so that the position of the first blade to be processed on the integral bladed disk 4 is opposite to the initial position of the combined sleeve cathode 1, and maintain a certain initial processing gap between the two.

[0027] Step 2: Connect the integral bladed disk 4 to the positive terminal of the power supply, connect the combined sleeve cathode 1 to the negative terminal of the power supply through the zoned power control device 2, and turn on the electrolyte supply system.

[0028] Step 3: Perform rough machining of the first blade of the integral bladed disk 4. The machine tool spindle drives the combined sleeve cathode to feed radially along the integral bladed disk, that is, to move along the X-axis slide 501. The zoned power control device 2 simultaneously and sensitively identifies the movement status and supplies power only to the end face sleeve cathode 101. The rough machining of the blade profile is completed through the end face sleeve cathode 101, and a blade blank with a certain allowance is initially machined.

[0029] Step 4: Perform the blade profile finishing process. Under the same working conditions as after the roughing in Step 3, the machine tool spindle drives the combined sleeve cathode 1 to change its radial feed to movement along the normal direction of the blade's facet or back profile, i.e., along the Y-axis slide 502. The zoned power control device 2 de-energizes the end face sleeve cathode 101, supplying power only to the facet cathode 103 or the back profile cathode 105 for blade facet or back profile finishing. After the blade facet or back profile finishing is completed, the machine tool drives the combined sleeve cathode 1 to move along the normal direction of the back or facet. The zoned power control device 2 de-energizes the facet cathode 103 or the back profile cathode 105, supplying power only to the back profile cathode 105 or the facet cathode 103, achieving blade back or facet finishing. This completes the integrated roughing and finishing precision electrolytic machining of the first blade of the entire bladed disk within one machining operation.

[0030] Step 5: After the first blade in Step 4 is processed, the combined sleeve cathode 1 returns to the initial processing position, and the indexing turntable 504 is driven to rotate the entire bladed disk 4 around its center by an angle of 360° / N degrees (N is the number of blades), so that it is exactly in the processing position of the second blade, and the rough and finish processing of the second blade is carried out; repeat the above processing steps to complete the rough and finish processing of all blades of the entire bladed disk 4 in sequence.

[0031] Step 6: Turn off the power and electrolyte supply system.

Claims

1. A combined sleeve-type cathode, characterized in that: It includes an insulating plate (107), an insulating base (108), an end-face sleeve-shaped cathode (101), a blade basin-shaped surface cathode (103), and a blade back-shaped surface cathode (105). The end-face sleeve-shaped cathode (101) is a hollow structure. The end-face sleeve-shaped cathode (101) is located on the front side of the insulating plate (107), and the insulating base (108) is located on the rear side of the insulating plate (107). The blade basin-shaped surface cathode (103) and the blade back-shaped surface cathode (105) are located on both sides of the insulating plate (107). The three cathodes, the end-face sleeve-shaped cathode (101), the blade basin-shaped surface cathode (103), and the blade back-shaped surface cathode (105), are insulated from each other and are connected to their respective lead-in posts. Each lead-in post passes through the insulating base (108) and is connected to the zone control device.

2. The method for integrated roughing and finishing of the combined sleeve-type cathode integral bladed disk as described in claim 1, characterized by the following processes: Step 1: Install the integral bladed disk on the indexing turntable, install the combined sleeve cathode on the machine tool spindle, and rotate the integral bladed disk through the machine tool indexing turntable so that the position of the first blade to be machined on the integral bladed disk is opposite to the initial position of the combined sleeve cathode, and maintain a certain initial machining gap between the two. Step 2: Connect the integral bladed disk blank to the positive terminal of the power supply, connect the combined sleeve cathode to the negative terminal of the power supply through the zoned power control device, and turn on the electrolyte supply system. Step 3: Perform the rough machining of the first blade of the integral bladed disk; the machine tool spindle drives the combined sleeve cathode to feed radially along the integral bladed disk, that is, to move along the X-axis slide. The zoned power control device simultaneously and sensitively identifies the motion state and supplies power only to the end face sleeve cathode. The rough machining of the blade profile is completed through the end face sleeve cathode, and a blade blank with a certain allowance is initially machined. Step 4: Perform blade profile finishing process; Under the same working conditions after the roughing in Step 3, the machine tool spindle drives the combined sleeve cathode to change from radial feed to movement along the normal direction of the blade basin or blade back profile, that is, movement along the Y-axis slide. The zone control device cuts off the power to the end face sleeve cathode and supplies power only to the blade basin or blade back profile cathode to perform blade basin or blade back profile finishing; After the blade basin or blade back profile finishing is completed, the machine tool drives the combined sleeve cathode to move along the normal direction of the blade back or blade basin profile. The zone control device cuts off the power to the blade basin or blade back profile cathode and supplies power only to the blade back or blade basin profile cathode to achieve blade back or blade basin profile finishing. The roughing and finishing integrated precision electrolytic machining of the first blade of the whole bladed disk is completed in one machining process; Step 5: After the first blade in Step 4 is processed, the combined sleeve cathode returns to the initial processing position. The indexing turntable is driven to rotate the entire bladed disk blank around the center of the blank by an angle of 360° / N degrees, where N is the number of blades, so that it is exactly in the processing position of the second blade. The second blade is then subjected to rough and finish machining. The above processing steps are repeated to complete the rough and finish machining of all blades of the entire bladed disk in sequence. Step 6: Turn off the power and electrolyte supply system.

Images