CN109909570B - Sleeve material electrolytic machining clamp and method for diffuser with insoluble blade tail edge - Google Patents

Abstract

The invention discloses a sleeve electrolytic machining fixture of a blade trailing edge insoluble diffuser and a method thereof, belonging to the field of electrolytic machining. The device of the present invention is divided into left and right parts, the middle of the left and right clamp bodies is the cathode and the insulating block, a controllable liquid outlet gap is formed between the two side clamp bodies and the outer contour of the cathode, and the flow mode of the electrolyte is a liquid outlet corner type , the electrolyte flows in from the upper end of the blade and flows out from the liquid outlet gap, and forms a closed flow field through the gap between the insulating sleeve, the cathode and the clamp. The insulating block is attached to the non-machined surface of the cathode, and the three-side machining of the leading edge, the blade basin and the blade back of the blade is realized. The concentric arc surfaces of the front and trailing edge support blocks are used to clamp the annular workpiece. During the machining process, the machined blade protective sleeve is always sleeved on the machined adjacent blades, effectively avoiding stray corrosion of the machined blade. The invention solves the problems that the pressure of the clamp is too large and the electrolyte is easy to leak during the electrolytic processing of the diffuser sleeve, and is beneficial to improve the stability of the flow field and improve the processing quality.

Description

Electrolytic machining jig for non-dissolving diffuser at blade trailing edge and method therefor

technical field

The invention discloses a sleeve electrolytic machining fixture for a blade trailing edge insoluble diffuser and a method thereof, belonging to the field of electrolytic machining, and in particular to the field of electrolytic machining of aero-engine diffuser sleeves.

Background technique

Electrochemical machining technology is a method based on the principle of electrochemical anodic dissolution to erode the metal material of the workpiece to achieve the purpose of processing. Cutting materials and parts with complex blade profiles show great advantages and are widely used in aviation, aerospace and other fields.

Electrochemical processing electrolyte flow modes mainly include forward flow, reverse flow and lateral flow. In the field of electrolytic machining, the sleeve electrolytic machining is suitable for machining the parts of the blade with equal section, so it has its unique advantages in the electrolytic machining of the diffuser, and its processing efficiency is high and the fixture design is simple. Although NEM has many advantages, because the technology and process development are not perfect, there are still many areas that need to be improved and improved. For example, the problem of flow field stability is a problem that has not been completely solved in NEM, and has a great impact on the processing quality.

In the patent "An integral cavity screw feed electrolytic machining fixture" (application number 201710135172.3, applicant Anhui University of Science and Technology, inventor Sun Lunye Zhang Xingguang Zhou Qinghong Wang Long Zhang Zheng Huang Shaofu), a lateral flow of electrolyte is proposed. The electrolytic machining fixture, through the gap between the fixture and the workpiece and the corresponding sealing device, keeps the electrolyte flow field inside the fixture always stable during processing, but the processing method of the invention does not control the separation of the processed profile and the electrolyte , stray corrosion still exists on the processed profile during the processing.

In the article "Flow Field Design and Experiment of Electrolytic Machining of Circumferential Blades of Integral Components" (author Peng Suhao, Xu Zhengyang, Guzhou, Zhu Dong, Liu Jia, Journal of Nanjing University of Aeronautics and Astronautics, No. 5, 2014), an electrode with a built-in insulating cavity is used. For the axial vane of the nested electrolytic machining diffuser, the electrolyte enters the machining gap from both sides of the blade back of the vane of the insulating cavity, and the flow mode of the electrolyte is positive flushing. This method effectively reduces stray corrosion. However, since there is still electrolyte entering the machined surface from the gap between the insulating cavity and the machined area, the machined area is still subject to stray corrosion.

In the patent "Nesting Electrolytic Processing Device with Insoluble Blade Trailing Edge and Its Processing Method" (application number 201710880612.8, applicant Nanjing University of Aeronautics and Astronautics, inventor Zhu Dong, Xu Juewu, Xu Zhengyang, and Zhu Di), a sealed type electrolytic nesting is proposed. Processing the fixture, the processing method of the invention can realize the electrolytic machining of the three-sided machining edge, and can reduce the leakage of electrolyte during processing, but because the fixture is a closed structure, the pressure on the fixture and the workpiece during processing gradually increases, to a certain extent. It will affect the feed of the workpiece, and even cause the workpiece to crawl in severe cases.

Although the existing sealed-type electrolytic machining fixture can realize the machining of the diffuser parts whose trailing edge and the outer circle of the hub are co-cylindrical, the device is complicated, the installation is difficult, the short-circuit phenomenon often occurs in actual processing, and the flow field is uniform. Poor performance is not conducive to improving processing stability and processing accuracy; and the protection of the processed area cannot effectively reduce the stray corrosion suffered by the processing area. Therefore, it is urgent to find a nested electrolytic machining fixture with simple structure, convenient installation and stable electrolyte flow field in the processing area, so as to realize high-efficiency electrolytic machining of diffuser parts that do not dissolve the trailing edge of the blade.

SUMMARY OF THE INVENTION

The purpose of the present invention is to aim at the deficiencies of the prior art, and to provide an electrolytic machining fixture for the insoluble diffuser at the trailing edge of the blade and a method thereof, so as to effectively process the expansion of the co-cylindrical surface of the trailing edge of the blade and the outer circle of the hub. Press parts.

A sleeve electrolytic machining fixture for an insoluble diffuser at the trailing edge of a blade, characterized in that:

The electrolytic machining fixture includes a mounting plate, a leading edge insulating block, a trailing edge insulating block, and two left and right clamping bodies. The left and right clamping bodies have similar structures, and are both composed of a supporting steel plate, a cover plate, a leading edge supporting block, and a tail. The cover plate is fixed on the surface of the supporting steel plate; the leading edge support block and the trailing edge support block are fixed on the surface of the cover plate; the surfaces corresponding to the leading edge support block and the trailing edge support block are two concentric arcs The supporting steel plate, the cover plate, the leading edge support block and the trailing edge support block are all provided with a segment channel, and the contour of the segment channel is concentric with the front and trailing edge support blocks. The arc surface is a concentric arc; the clip body is installed on the mounting plate through the above-mentioned segment channel by screws; the right side of the cover plate of the left clip body and the left side of the right clip body are provided with two pictographic grooves , the groove contour is the same as the outer contour of the processed blade protective sleeve; the leading edge insulating block and the trailing edge insulating block are installed on the mounting plate, located in the middle of the left and right clamp bodies.

The described method for the nesting process of a nesting electrolytic machining fixture for the insoluble diffuser at the trailing edge of the blade is characterized in that: the annular base part of the workpiece is clamped on the leading edge support block and the trailing edge support of the left and right two clamp bodies The parts to be processed are located in the middle of the left and right clamping bodies; the cathode is installed on the cathode base, and the to-be-processed part of the workpiece is facing the cathode; the left and right clamping bodies They are respectively fixed on the left and right sides of the cathode; there are gaps for liquid discharge between the two sides of the cathode and the left and right clamps respectively; the two processed blade protective sleeves on the left and right clamps are sleeved on the adjacent On the machined blade, and installed in the pictographic groove of the cover plate through clearance fit; the extension of the trailing edge insulating block is set in the gap between the outer circular surface of the workpiece and the non-machined edge at the cathode trailing edge, so as to protect the expansion The trailing edge part of the compressor blade cannot form an electric field to avoid corrosion; the electrolyte flow mode during the electrolytic process of the casing is a forward flushing type. The gap between the insulating sleeve and the inner wall of the cathode flows through the processing area from the tip to the root of the blade, and the liquid is discharged through the gap between the outer wall of the cathode and the left and right clamps.

The sleeve electrolytic machining fixture for the non-dissolving diffuser at the trailing edge of the blade is characterized in that: the leading edge insulating block and the trailing edge insulating block have a guide slope; the guide slope is located on the leading edge insulating block or the trailing edge insulating block. The inner side of the contact surface of the block and the cathode prevents the cavitation phenomenon caused by the excessive flow rate when the electrolyte flow direction is abruptly changed by 90 degrees, so as to ensure sufficient liquid supply to the processing area of the blade trailing edge.

The advantages of the present invention are:

1. A simple structure and convenient installation are proposed based on the positive-flushing flow field nesting electrolytic machining fixture. The device is a block-type clamp, which replaces the existing integral clamp, which greatly reduces the material and processing cost of the clamp; The structure of the fixture is further simplified; the left and right fixtures are installed independently, and the tightness between the fixture and the workpiece and the size of the liquid outlet gap can be adjusted by adjusting the screws installed in the fan-shaped channel. The installation is convenient and fast, and the time for disassembling and assembling the fixture during continuous processing is reduced. , improve processing efficiency;

2. The fixture adopts a block structure. Compared with the existing closed fixture, on the basis of maintaining a stable flow field in the processing area, the rest of the electrolyte can be quickly returned to the circulation system, avoiding the need for closed fixtures. The inner cavity accumulates, and the electrolyte pressure gradually increases during processing. The block-type clamp is beneficial to reduce the pressure on the clamp and the workpiece, reduce the deformation of the clamp, and avoid the phenomenon of crawling;

3. Improve the uniformity of electrolyte flow in the processing area. Both the front and trailing edge insulating blocks are provided with a slope, which can guide the flow of electrolyte during processing to avoid the inability to accurately supply liquid at the root of the insulating block due to the drastic change in the flow direction of the electrolyte, and prevent the phenomenon of lack of liquid. At the same time, the device can control the accessibility of the electrolyte flow by adjusting the size of the liquid outlet gap between the inner wall of the two clamps and the outer contour of the cathode, so as to ensure that there is sufficient electrolyte at the trailing edge of the blade. The liquid outlet corner flow field can effectively control the flow rate of the electrolyte and improve the uniformity of the flow field.

Description of drawings

Figure 1 is a fixture assembly diagram;

Fig. 2 is a fixture structure diagram;

Fig. 3 is the schematic diagram of electrolyte flow mode;

Fig. 4 is the structural representation of the connection between the fixture and the workpiece;

Figure 5 is a sectional view of the interior of the fixture;

Fig. 6 is the electrolytic machining method of the nesting material without dissolving the trailing edge of the blade;

Among them: 1-installation plate, 2-liquid inlet, 3-cathode base, 4-insulation sleeve, 5-cathode, 6-workpiece, 7-leading edge insulating block, 8-trailing edge insulating block, 9-supporting steel plate, 10- Cover plate, 11- Leading edge support block, 12- Trailing edge support block, 13- Processed blade protective sleeve, 14- Machining tooling, 15- Workpiece outer circular surface, 16- Cathode trailing edge non-machined edge.

Detailed ways

The present invention will be further described below in conjunction with specific embodiments.

Implementing the present invention - "a nesting electrolytic machining fixture for a diffuser with special structure", the device mainly includes a leading edge insulating block, a trailing edge insulating block, a supporting steel plate, a cover plate, a leading edge supporting block, and a trailing edge supporting block , has been processed blade protective cover.

The supporting steel plate is made of stainless steel; the leading edge insulating block, the trailing edge insulating block, the cover plate, the leading edge supporting block, the trailing edge supporting block and the processed blade protective cover are all made of epoxy resin; the supporting steel plate, the cover plate, The outer contour of the leading edge support block, the trailing edge support block and the processed blade protective sleeve can be designed according to the shape of the parts to be processed, and the width of the fan-shaped channel on the upper and lower sides of the fixture can be adjusted according to the processing conditions.

The process of adopting the electrolytic machining workpiece of the fixture of the present invention mainly comprises the following steps:

Step 1: Install the cathode body assembly (cathode, insulating sleeve, leading edge insulating block, trailing edge insulating block) on the cathode base, and connect the cathode to the negative electrode of the power supply;

Step 2: Install the workpiece and connect it to the positive pole of the power supply;

Step 3: Set the tool, determine the initial machining position, and calculate the initial machining gap;

Step 4: Install the fixture to connect the electrolyte inlet and outlet with the electrolyte circulation system;

Step 5: Start the heating system, and when the temperature of the electrolyte is heated to 30°C, start the constant temperature system;

Step 6: Start the electrolyte circulation system, and pass the electrolyte through the liquid inlet.

Step 7: Turn on the DC power supply and energize the cathode and anode.

Step 8: Start the operation program of the CNC machine tool, and the anode workpiece is fed along the axis of the workpiece. Under the action of the electrolytic corrosion of the cathode, the material of the anode workpiece is gradually removed. The three sides of the back of the blade, and the two sides of the insulating block are respectively fitted with the outer circular surface of the anode workpiece and the non-machined edge of the cathode, which protects the outer circular surface of the workpiece from electrolytic corrosion. With the progress of electrolytic machining, the shape of the desired blade is gradually set.

Step 9: After the processing of a single blade is completed, the power is turned off, the electrolyte circulation system is closed, the workpiece is returned to the initial position, the fixture is removed, the workpiece blank is indexed, and the processing of the next blade is ready to start.

Claims (3)

1. The utility model provides a cover material electrolytic machining anchor clamps of insoluble diffuser of blade trailing edge which characterized in that:

the electrolytic machining clamp comprises a mounting disc (14), a front edge insulating block (7), a tail edge insulating block (8) and a left clamp body and a right clamp body;

the left clamp body and the right clamp body are similar in structure and are respectively composed of a supporting steel plate (9), a cover plate (10), a front edge supporting block (11) and a tail edge supporting block (12); wherein the cover plate (10) is fixed on the surface of the supporting steel plate (9); the front edge supporting block (11) and the tail edge supporting block (12) are fixed on the surface of the cover plate (10); the corresponding surfaces of the front edge supporting block (11) and the tail edge supporting block (12) are two concentric arc surfaces which are used for mutually matching and clamping an annular workpiece; the supporting steel plate (9), the cover plate (10), the front edge supporting block (11) and the tail edge supporting block (12) are all provided with sector channels, and the outlines of the sector channels and the concentric arc surfaces of the front edge supporting block and the tail edge supporting block are concentric arcs; the clamp body is arranged on the mounting plate (14) through the sector channel by using a screw;

the right side of the cover plate (10) of the left fixture body and the left side of the cover plate (10) of the right fixture body are both provided with two pictographic grooves, and the outline of each groove is the same as the outline of the machined blade protective sleeve (13);

the front edge insulating block (7) and the tail edge insulating block (8) are arranged on the mounting disc (14) and are positioned between the left clamp body and the right clamp body.

2. The trepanning electrochemical machining clamp for the diffuser with the insoluble blade trailing edge as claimed in claim 1, wherein:

the leading edge insulating block (7) and the trailing edge insulating block (8) are both provided with a flow guide inclined plane; the diversion inclined plane is positioned on the inner side of the binding surface of the front edge insulating block (7) or the tail edge insulating block (8) and the cathode (5).

3. The trepanning processing method of the trepanning electrochemical machining fixture for the diffuser insoluble in the trailing edge of the blade of claim 1 is characterized by comprising the following steps:

the annular base body part of the workpiece (6) is clamped in two concentric circular arc surfaces formed between the front edge supporting block (11) and the tail edge supporting block (12) of the left fixture body and the right fixture body; the part to be processed is positioned between the left clamp body and the right clamp body;

the cathode (5) is arranged on the cathode base (3), and the part to be processed of the workpiece (6) is opposite to the cathode (5); the left and right clamp bodies are respectively fixed on the left and right sides of the cathode; gaps for liquid outlet are respectively arranged between the two sides of the cathode and the left and right clamps;

two processed blade protective sleeves (13) on the left and right clamp bodies are sleeved on adjacent processed blades and are arranged in the pictographic grooves of the cover plate (10) in a clearance fit manner;

the extending part of the tail edge insulating block (8) is arranged in a gap between an outer circular surface (15) of the workpiece and a non-processing edge (16) at the tail edge of the cathode;

in the set material electrolytic machining process, electrolyte flows in a mode that the electrolyte is fed from the liquid inlet (2), flows into a gap between the insulating sleeve (4) and the cathode base (3) through the liquid inlet, flows through the machining area from the blade tip to the blade root direction through a gap between the insulating sleeve (4) and the inner wall of the cathode, and flows out through a gap between the outer wall of the cathode and the left and right clamps.

Images