Integrally closed blade ring channel electrochemical machining device and method

Abstract

The present invention relates to an electrolytic machining device and method for an integral closed blade ring channel, and belongs to the field of electrolytic machining technology. The invention seeks the optimal installation angle of the workpiece according to the degree of distortion of the channel, that is, the end face of the workpiece is installed at a certain angle to the coordinate axis X of the machine tool. At this angle, the blade basin and back margins on both sides of the channel projected by the cathode along the X-axis are uniform. During machining, the cathode is fed along the Y-axis, and the workpiece is fed along the X-axis while rotating along the C-axis to achieve twisted channel machining. Since the workpiece is installed at an angle to the cathode, an inlet liquid sealing device is designed to ensure the stability of the flow field in the initial machining stage. The flow field will change drastically at the moment the blade ring channel is opened, and an outlet liquid sealing device is designed to achieve flow field stability in the final stage of machining. The tilted installation of the workpiece reduces the angle of rotation of the workpiece during feeding, thereby improving machining efficiency and accuracy.

Description

Technical Field

[0001] The present invention belongs to the field of electrolytic machining, and in particular relates to an electrolytic machining device and method for an integral closed blade ring channel. Background Art

[0002] The integral closed blade ring is a new component structure used in advanced aircraft engines. The blades of this component are highly twisted and the airflow channel is narrow. The material of the aircraft engine blade disk is generally difficult to machine, such as nickel-based high-temperature alloys. Traditional mechanical processing methods result in high tool wear and high processing costs. Currently, the closed integral blade ring is mainly processed by CNC milling. As the milling cutter penetrates deeper into the processing channel, the vibration amplitude of the milling cutter increases, which brings certain difficulties to the processing. Electrochemical machining is a typical non-contact processing method. Compared with traditional mechanical processing methods, electrochemical machining has inherent advantages such as no tool wear, low cost, and high processing efficiency.

[0003] Chinese patent CN115781193A proposes using wire cutting technology to open the blade ring channel. It first determines the spatial angle A and spatial angle C when the vertical projection area of ​​each cavity matrix to be cut off on the matrix of the part to be processed is the largest, and then processes wire cutting wire guide holes on the cavity matrix to be cut off. The semi-finished product is obtained by wire cutting technology, and then the semi-finished product is fine-processed on a milling machine.

[0004] Patent CN111008445A proposes a method for determining the tool axis for fixed-axis milling. This method can help process personnel save the steps of manually specifying the tool axis, quickly complete the compilation of CNC programs, and reduce the possibility of problems such as excessive residual volume and long processing time caused by poor manually specified tool axis.

[0005] Patent CN108994402A uses an electrospark machining method to machine closed blade rings, which is mainly divided into two steps: rough machining and fine machining.

[0006] Patent CN116117251A proposes a method for electrochemical machining of screw-in blade channels to achieve electrochemical rough machining of the entire closed blade ring.

[0007] At present, the machining accuracy and stability of electrochemically machined integral closed blade rings need to be further improved, and further research is urgently needed. Summary of the Invention

[0008] The present invention aims to provide an electrochemical machining device and method for an integral closed blade ring channel with high precision and good stability.

[0009] An integral closed blade ring channel electrolytic machining device is characterized in that: it includes: a tooling, a workpiece blank, a cathode, a liquid inlet pipe, an inlet liquid sealing device, and an outlet liquid sealing device; the above-mentioned workpiece blank is mounted on the upper surface of the tooling; the above-mentioned inlet liquid sealing device is tightly attached to the upper surface of the workpiece blank, and the inlet liquid sealing device is provided with a channel, the cross-sectional profile of the channel corresponds to the shape of the cathode; the above-mentioned outlet liquid sealing device includes a high-pressure channel and an overflow channel; the inlet of the high-pressure channel is connected to the high-pressure liquid inlet pipe, and the high-pressure liquid inlet pipe passes through the electrolyte with a pressure greater than the processing area pressure, and the outlet of the high-pressure channel is sealed and docked with the lower surface of the workpiece blank, and its position is located at the end position of the closed blade ring channel to be machined; the overflow channel is connected to the water tank; the above-mentioned inlet liquid sealing device and outlet liquid sealing device are made of insulating material; the above-mentioned tooling and liquid inlet pipe are respectively connected to the X and Y axes of the machine tool; the cathode is connected to the liquid inlet pipe.

[0010] The processing method using the above-mentioned integral closed blade ring channel electrolytic processing device is characterized in that it includes the following processes: Step 1, determining the installation angle between the end face of the workpiece blank and the machine tool coordinate axis X by the following principle: According to the degree of distortion of the closed blade ring channel to be processed, there is an optimal initial angle α between the end face of the workpiece blank and the cathode end face, at which the blade basin and back margins on both sides of the channel projected along the X-axis by the cathode end face are uniform; Step 2, determining the distance from both sides of the cathode to the side of the inlet sealing device channel at the beginning of processing by the following principle: Since there is an angle between the end face of the workpiece blank and the cathode end face in step 1, the processing gap between the cathode end face and the end face of the workpiece blank is inconsistent in size, which will cause the electrolyte sprayed from the center of the cathode end face to flow out from the side with a larger processing gap, and the side with a smaller processing gap will lack liquid; In order to eliminate the above-mentioned influence, at the beginning of processing, the cathode processing part is located in the inlet sealing device channel, and the processing gap is large The lateral distance from the cathode side on one side to the side of the sealing liquid device channel is smaller than the lateral distance on the side with the smaller processing gap; at the same time, the inlet sealing liquid device channel wraps the cathode processing part and ensures that it does not interfere with the non-processing part of the cathode during the processing; step 3, during processing, the cathode moves along the Y axis, and the workpiece blank moves along the X axis and rotates along the C axis at the same time; during processing, due to the initial tilted installation of the workpiece blank, the rotation angle of the workpiece blank during processing is reduced, and the processing stability is improved; step 4, the flow field will change drastically at the moment the leaf ring channel is opened, the electrolyte will flow out from the opening, the electrolyte flow rate in the unprocessed area will drop rapidly, the electrolysis product cannot be removed in time, and a short circuit will occur; since the high-pressure channel is connected to the high-pressure liquid inlet pipe, an electrolyte with a pressure greater than the processing area pressure is introduced, so that the electrolyte continues to flow out along the original path, avoiding the occurrence of the above-mentioned flow field mutation and improving the processing stability.

[0011] The advantages of the present invention are: by tilting the workpiece and designing an inlet flow field stabilizing device, the machining accuracy and the stability of the machining process are improved.

[0012] A tilted initial workpiece installation method is proposed to improve machining accuracy and stability. The cathode end face and the workpiece blank end face initially form an angle α, which reduces the workpiece rotation angle during machining, improves the stability of the flow field during machining, and achieves high consistency in the machining channel margin.

[0013] A flow field stabilization device for the liquid inlet was designed to achieve non-parallel machining between the cathode and the workpiece end face, improving initial machining stability. Initially, the cathode machining portion is located within the inlet sealing device channel. The lateral distance from the cathode side on the side with the larger machining gap to the side of the sealing device channel is shorter than the lateral distance on the side with the smaller machining gap.

[0014] An outlet flow field stabilization device is designed to achieve stable machining during channel processing and improve stability in the later stages of machining. Electrolyte at a pressure greater than the machining area is passed through a high-pressure pipeline, allowing the electrolyte to continue flowing along its original path and promptly remove electrolysis products. During machining, electrolyte is continuously passed through the outlet sealing device. Before the leaf ring channel is opened, the electrolyte in the outlet sealing device cannot flow back. A return line is designed at the liquid inlet of the device, equipped with a relief valve to ensure that the electrolyte can flow back before the leaf ring channel is opened. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the overall closed blade ring processing device;

[0016] Figure 2 Schematic diagram of the inlet liquid sealing device;

[0017] Figure 3 Schematic diagram of the outlet liquid sealing device;

[0018] The reference numbers in the figure are: 1-tooling, 2-workpiece blank, 3-cathode, 4-liquid inlet pipe, 5-inlet liquid sealing device, 6-outlet liquid sealing device. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0020] The present invention provides a closed component channel electrolytic machining method and flow field design, and the specific machining steps are as follows:

[0021] 1) Connect the fixture, liquid inlet pipe and machine tool, connect the cathode to the liquid inlet pipe, and align them. Install the blank on the fixture, align the tool, and connect the outlet sealing device. Figure 1 ;

[0022] 2) The workpiece is initially tilted, that is, the cathode end surface and the blank form an angle α in the initial processing position, and the inlet sealing device is installed on the upper surface of the blank.

[0023] 3) The positive and negative poles of the power supply are connected to the workpiece and the cathode respectively, the electrolyte system circulates the liquid, the power is turned on, the machine tool processing program is started, and processing begins.

[0024] 4) After processing is completed, remove the rough-machined blade ring.

[0025] The above description is only a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any equivalent structural changes made using the contents of the description and drawings of the present invention should be included in the patent protection scope of the invention.

Claims

1. An integral closed blade ring channel electrochemical machining device, characterized by: It comprises a tool (1), a workpiece blank (2), a cathode (3), a liquid inlet pipe (4), an inlet liquid sealing device (5), and an outlet liquid sealing device (6); The workpiece blank (2) is mounted on the upper surface of the tooling (1); The inlet sealing device (5) is in close contact with the upper surface of the workpiece blank (2), and the inlet sealing device (5) is provided with a channel, the cross-sectional profile of the channel corresponding to the shape of the cathode; The above-mentioned outlet sealing device (6) includes a high-pressure channel and an overflow channel; the inlet of the high-pressure channel is connected to the high-pressure liquid inlet pipe, and the high-pressure liquid inlet pipe passes through the electrolyte with a pressure greater than the processing area pressure, and the outlet of the high-pressure channel is sealed and docked with the lower surface of the workpiece blank (2), and its position is located at the end of the closed leaf ring channel to be processed; the overflow channel is connected to the water tank; The inlet liquid sealing device (5) and the outlet liquid sealing device (6) are made of insulating material; The tooling (1) and the liquid inlet pipe (4) are connected to the X-axis and Y-axis of the machine tool respectively; the cathode (3) is connected to the liquid inlet pipe (4); There is an optimal initial angle α between the end face of the workpiece blank (2) and the end face of the cathode (3), at which the blade basin and blade back margins on both sides of the channel projected along the X-axis by the cathode end face are uniform.

2. A machining method using the electrochemical machining device for the integral closed blade ring channel according to claim 1, characterized in that The following processes are included: Step 1: Determine the installation angle between the end face of the workpiece blank and the machine tool coordinate axis X according to the following principle: according to the degree of distortion of the closed blade ring channel to be machined, there is an optimal initial angle α between the end face of the workpiece blank (2) and the end face of the cathode (3), at which the blade basin and blade back margins on both sides of the channel projected along the X axis are uniform; Step 2, determine the distances from both sides of the cathode to the side of the inlet sealing device channel at the beginning of processing by the following principle: since there is an angle between the end face of the workpiece blank (2) and the end face of the cathode (3) in step 1, the processing gaps between the cathode end face and the workpiece blank end face are inconsistent in size, which will cause the electrolyte ejected from the center of the cathode end face to flow out from the side with the larger processing gap, and the side with the smaller processing gap will lack liquid; to eliminate the influence, at the beginning of processing, the processing part of the cathode (3) is located in the inlet sealing device channel, and the lateral distance from the cathode side on the side with the larger processing gap to the side of the sealing device channel is smaller than the lateral distance on the side with the smaller processing gap; at the same time, the inlet sealing device channel wraps the cathode processing part and ensures that it does not interfere with the non-processing part of the cathode during processing; Step 3: During processing, the cathode (3) moves along the Y axis, and the workpiece blank (2) moves along the X axis and rotates along the C axis; during the processing, since the workpiece blank (2) is initially installed at an angle, the rotation angle of the workpiece blank (2) during the processing is reduced, thereby improving the processing stability; Step 4: The flow field will change dramatically the moment the blade ring channel is opened. The electrolyte will flow out from the opening, and the electrolyte flow rate in the unprocessed area will drop rapidly. The electrolysis products cannot be removed in time, and a short circuit will occur. Since the high-pressure channel is connected to the high-pressure liquid inlet pipe, an electrolyte with a pressure greater than that of the processing area is introduced, causing the electrolyte to continue to flow out along the original path, avoiding the occurrence of the above-mentioned flow field mutation and improving the processing stability.

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