阅读说明：本技术 一种压气机工作叶片电火花+磨粒流组合加工方法 (Electric spark and abrasive flow combined machining method for working blade of gas compressor ) 是由 孙玉利 范武林 杨范轩 赵建社 于 2021-09-10 设计创作，主要内容包括：一种压气机工作叶片电火花+磨粒流组合加工方法,其特征是它包括以下步骤：1)将加工好榫头的多个叶片和加工好榫槽的定位轮盘装配成一个完整叶盘；2)在电火花成形加工机床上利用成组电极依次对所有叶片的叶身进行电火花粗加工；3)利用成形电极依次对所有叶片的叶身进行电火花精加工；4)利用成形电极依次对所有叶片的进/排气边进行电火花精加工；5)采用磨粒流光整工艺对叶盘的所有叶间流道进行并行抛光；6)将叶盘从磨粒流机床上拆卸,对叶片拆卸、清洗和烘干,进行后续检测。本发明能实现复杂结构工作叶片的精密成形加工和多个叶片在同一抛光设备上的并行抛光,提高了压气机工作叶片加工的良品率和加工效率,同时降低加工成本。(An electric spark and abrasive flow combined machining method for working blades of a gas compressor is characterized by comprising the following steps of: 1) assembling a plurality of blades with processed tenons and a positioning wheel disc with processed mortises into a complete blade disc; 2) using a group of electrodes to perform electric spark rough machining on blade bodies of all blades in sequence on an electric spark forming machining machine tool; 3) sequentially carrying out electric spark finish machining on blade bodies of all the blades by using a forming electrode; 4) carrying out electric spark finish machining on the air inlet/outlet edges of all the blades by utilizing a forming electrode in sequence; 5) polishing all inter-leaf flow channels of the leaf disc in parallel by adopting an abrasive particle flow finishing process; 6) and (4) disassembling the blade disc from the abrasive flow machine tool, disassembling, cleaning and drying the blade, and carrying out subsequent detection. The invention can realize the precise forming processing of the working blade with a complex structure and the parallel polishing of a plurality of blades on the same polishing device, improve the yield and the processing efficiency of the working blade of the gas compressor, and simultaneously reduce the processing cost.)

1. A combined machining method of an electric spark and abrasive flow for working blades of a gas compressor is characterized in that a plurality of blades with tenons and a positioning wheel disc with mortises are assembled into a complete blade disc, then, all inter-blade runners and air inlet/outlet edges of the assembled blade disc are sequentially formed and machined by an electric spark forming machine tool, and finally all inter-blade runners of the blade disc are polished on the abrasive flow machining machine tool at the same time, so that the precise finishing machining of the blade disc of the split type blade gas compressor is realized.

2. The process according to claim 1, characterized in that it comprises the following steps:

s1, assembling the plurality of blades with the processed tenons and the positioning wheel disc with the processed mortises into a complete blade disc;

s2, adopting grouped electrodes to perform electric spark rough machining on the blade bodies of all the blades on an electric spark forming machine tool in sequence;

s3, performing electric spark finish machining on the blade bodies of all the blades by using the forming electrodes in sequence;

s4, performing electric spark finish machining on the air inlet/outlet edges of all the blades by using the forming electrodes in sequence;

s5, polishing all inter-leaf flow channels of the leaf disc in parallel by adopting a abrasive particle flow finishing process;

and S6, disassembling the blade disc from the abrasive flow machine tool, disassembling, cleaning and drying each blade of the blade disc, and carrying out subsequent detection.

3. The method of claim 2, wherein the blade of S1 is forged or cast into a blank, and is machined to form the tip and the tenon, and the assembled disk has a through inter-blade channel; the positioning wheel disc is an auxiliary fixture for providing installation positioning and tool setting reference for the blade to be processed; the positioning wheel disc is a disc or a hollow disc and is made of metal materials, and the end face of one side of the positioning wheel disc is provided with a feeler block; mortises with the same number as the blades to be processed are uniformly distributed on the outer circular surface of the disc, and the mortises are profiled with the tenons of the blades to be processed; the assembling is realized by installing tenons of all blades to be processed into mortises of the positioning wheel disc, the blades and the positioning wheel disc realize angular positioning and radial positioning through clearance fit of the tenons and the mortises, and axial positioning is realized through fitting of tenon side planes and corresponding end faces of the positioning wheel disc.

4. The process of claim 2, wherein said grouped electrodes of S2 are composed of a plurality of shaped electrodes distributed in a circular array, each electrode being of the same material, shape, size and mounting manner; all the electrodes are arranged on the same base and simultaneously participate in the rough machining of the blade bodies of the blades; in the rough machining process, vibration assistance is applied to the electrodes in the feeding direction of the grouped electrodes so as to improve the chip removal performance and ensure the stability of the rough machining process; the rough machining sequence of different blades is determined according to the same clockwise direction, namely, when rough machining of a group of blade bodies is completed, the blade disc rotates for a certain angle around the central axis clockwise or anticlockwise, position matching of an adjacent group of blades to be machined and a group of electrodes is realized, and then machining is continued until rough machining of all the blade bodies is completed.

5. The machining method according to claim 2, wherein the blade body described in S3 is divided into machining areas according to machining accessibility, and different machining areas are machined using different electrode working surfaces; the finish machining sequence of the different blades is determined according to an approximate symmetrical distribution principle, namely after the blade body of the blade A is machined, the position of an electrode is unchanged, the blade disc is rotated by a certain angle around the central axis clockwise or anticlockwise, the position matching of the blade B and the finish machining electrode is realized, the angular span of the blade B and the blade A is the largest, and then the machining is continued until the finish machining of all the blade bodies of the blades is completed, so that the deformation of a workpiece after the finish machining is reduced; the roughness of the surface line of the leaf body after finish machining is controlled to be Ra3.0 mu m-Ra1.0 mu m, the thickness of a recast layer on the machined surface is 0.002 mm-0.01 mm, and the finish machining should reserve 0.01 mm-0.05 mm of single-side process allowance for subsequent abrasive particle flow finishing.

6. The machining method according to claim 2, wherein the air intake side and the air discharge side in S4 are machined using shaped electrodes having different structures, respectively, and a working surface of the shaped electrode is formed to follow a target shape of a surface to be machined corresponding to the air intake/discharge side while being offset by an average discharge gap.

7. The processing method according to claim 2, characterized in that the single-side process allowance of the flow channel between the leaves of the leaf disc after polishing by the abrasive particle flow process in S5 is 0.01 mm-0.05 mm, the line roughness of the whole flow channel between the leaves after finishing processing is controlled to be Ra0.8 mu m-Ra0.4 mu m, and a recast layer on the processed surface is thoroughly removed; the abrasive flow polishing needs a guide ring to avoid the dimensional accuracy out-of-tolerance caused by over-polishing of the blade air inlet/outlet edges in the abrasive flow processing; the guide rings comprise an air inlet side guide ring and an air outlet side guide ring, and are made of carbon steel or stainless steel, each guide ring consists of a hollow disc and a plurality of uniformly distributed spokes with rectangular cross sections on the outer circular surface of the hollow disc, and the rectangular cross section side lines of the spokes are correspondingly parallel to the longitudinal cross section side line of the hollow disc; the number of the spokes of the guide ring is the same as that of the blades to be processed on the blade disc, and the outer diameter of the hollow cylinder of the gas inlet (exhaust) edge guide ring is 0-1.0 mm smaller than the outer diameter of the circle of the upper end face and the lower end face of the positioning wheel disc;

the air inlet and exhaust edge guide ring and the positioning wheel disc are coaxially arranged in the assembly process, and the lower upper end surface of the air inlet and exhaust edge guide ring is respectively attached to the upper end surface and the lower end surface of the positioning wheel disc; spokes on the air inlet and outlet edge guide ring and the air inlet and outlet edges of the blades are arranged in a one-to-one correspondence mode, and the guide ring and the positioning wheel disc realize angular positioning and radial positioning through a plurality of axial positioning pins; the shape of the central axis of each spoke on the air inlet and exhaust edge guide ring in the length direction is respectively the same as the shape of the central line of the air inlet and exhaust edge of the corresponding blade, the length of the spoke of the air inlet and exhaust edge guide ring is 1.0-3.0 mm larger than that of the air inlet and exhaust edge of the corresponding blade, and the tail end of the spoke extends out of the blade tip by 0.5-2.0 mm; the width of the rectangular section of the air inlet and exhaust side guide ring spoke is 2.0-5.0 mm; after the guide ring and the blade disc are assembled, the central axis of the spoke on the air inlet and exhaust edge guide ring is parallel to the central line of the air inlet and exhaust edge of the corresponding blade, the horizontal distance between the central axis and the central line of the air inlet and exhaust edge is 0-2.5 mm, and the vertical distance between the bottom surface of the spoke on the air inlet and exhaust edge guide ring and the central line of the air inlet and exhaust edge is 2.0-5.0 mm.

8. The machining method according to claim 2, wherein the cleaning in S6 includes sequentially performing high-pressure gas blowing, cleaning with a cleaning agent, ultrasonic cleaning, water jet cleaning, and absolute ethyl alcohol immersion cleaning.

9. A method of machining as claimed in claim 5, wherein the working surface of the electrode is contoured to the target shape of the surface to be machined and offset by an average discharge gap.

10. The machining method as claimed in claim 6, wherein the finishing sequence of the air inlet and outlet edges of different blades is determined according to the same clockwise direction, namely, when machining of one air inlet and outlet edge is completed, the blade disc is rotated around the central axis by an angle in the clockwise direction or the counterclockwise direction, the position matching of the adjacent air inlet and outlet edge and the electrode is realized, and then the machining is continued until finishing of all the air inlet and outlet edges is completed.

Technical Field

The invention relates to a technology for machining blades of an aero-engine compressor, in particular to a method for machining working blades of the compressor, and specifically relates to a method for machining the working blades of the compressor by combining electric sparks and abrasive flow.

Background

The working blade of the compressor of the aero-engine is generally assembled in a corresponding mortise on a wheel disc by adopting a tenon. At present, the working blade of the air compressor of the aircraft engine mainly adopts numerical control milling to finish the forming processing of the blade body of a single blade, and then adopts abrasive belt grinding to finish the polishing of the single blade and the forming processing of an air inlet/exhaust edge, and the processing method has the defects that: 1) the forming processing of the blade body depends on a numerical control milling cutter, and the cutting speed must be sacrificed in order to reduce the abrasion of the cutter, so the milling efficiency is low; 2) the surface quality of the blade body depends on the abrasive belt grinding technology for polishing, and because the processing accessibility of the abrasive belt is limited, the parallel polishing of a plurality of blades cannot be realized on the same processing equipment, so that the processing efficiency of the blades is reduced; 3) the forming and processing precision of the free-form surface blade edge depends on the abrasive belt grinding technology, and the abrasive belt does not have a profiling form, so that the yield of blade edge processing is reduced.

Disclosure of Invention

The invention aims to solve the processing problems that the size precision of the blade edge of a single compressor working blade is difficult to ensure in numerical control milling and abrasive belt grinding and the efficiency is low when the single blade is ground and polished by the abrasive belt, and provides an electric spark and abrasive flow combined processing method for the compressor working blade, so that the processing quality of the blade is ensured, the processing efficiency is improved, and the processing cost is reduced.

The technical scheme of the invention is as follows:

a combined machining method of an electric spark and abrasive flow for working blades of a gas compressor is characterized in that a plurality of blades with tenons and a positioning wheel disc with mortises are assembled into a complete blade disc, then, all inter-blade runners and air inlet/outlet edges of the assembled blade disc are sequentially formed and machined by an electric spark forming machine tool, and finally all inter-blade runners of the blade disc are polished on the abrasive flow machining machine tool at the same time, so that the precise finishing machining of the blade disc of the split type blade gas compressor is realized.

The method comprises the following specific steps:

s1, assembling the plurality of blades with the processed tenons and the positioning wheel disc with the processed mortises into a complete blade disc;

s2, adopting grouped electrodes to perform electric spark rough machining on the blade bodies of all the blades on an electric spark forming machine tool in sequence;

s3, performing electric spark finish machining on the blade bodies of all the blades by using the forming electrodes in sequence;

s4, performing electric spark finish machining on the air inlet/outlet edges of all the blades by using the forming electrodes in sequence;

s5, polishing all inter-leaf flow channels of the leaf disc in parallel by adopting a abrasive particle flow finishing process;

and S6, disassembling the blade disc from the abrasive flow machine tool, disassembling, cleaning and drying each blade of the blade disc, and carrying out subsequent detection.

Further, the blade described in step S1 is forged or cast into a blank, and the blade tip and the tenon are formed by machining, and the assembled blade disc has a through inter-blade flow channel.

Further, the positioning wheel disc described in step S1 is an auxiliary fixture for providing installation positioning and tool setting reference for the blade to be processed. The positioning wheel disc is a disc or a hollow disc and is made of metal materials, and the end face of one side of the positioning wheel disc is provided with a feeler block. The outer circular surface of the disc is uniformly distributed with mortises the same number with the blades to be processed, and the mortises are profiled with the tenons of the blades to be processed.

Further, the assembling in step S1 is implemented by installing tenons of all the blades to be machined into the mortises of the positioning disk, the blades and the positioning disk implement angular positioning and radial positioning through clearance fit of the tenon mortises, and implement axial positioning through fitting of the tenon side planes and the corresponding end faces of the positioning disk.

Further, the grouped electrodes described in step S2 are composed of a plurality of shaped electrodes distributed in a circular array, and the material, shape, size and installation manner of each electrode are the same. All the electrodes are arranged on the same base and participate in the rough machining of the blade bodies of the blades at the same time.

Further, in the rough machining process described in step S2, vibration assistance is applied to the electrodes in the feeding direction of the grouped electrodes to improve the chip removal performance and ensure the stability of the rough machining process.

Further, the rough machining sequence of the different blades in step S2 is determined according to the same clockwise direction, that is, when rough machining of one blade group is completed, the blade disc is rotated by a certain angle around the central axis clockwise (or counterclockwise), so that the position matching between the adjacent blade group to be machined and the electrode group is realized, and then machining is continued until rough machining of all the blade groups is completed.

Further, the blade body described in step S3 is divided into a plurality of machining areas according to the machining accessibility, and different machining areas are machined using different electrode working surfaces that are contoured and offset by an average discharge gap from the target shape corresponding to the surface to be machined.

Further, the finishing sequence of the different blades in step S3 is determined according to an (approximate) symmetric distribution principle, that is, after the blade body of the blade a is finished, the position of the electrode is unchanged, the blade disc is rotated by a certain angle around the central axis clockwise (or counterclockwise), the position pairing of the blade B (the angular span between the blade B and the blade a is the largest) and the position of the finishing electrode is realized, and then the machining is continued until finishing of all the blade bodies of the blades is finished, so as to reduce the deformation of the workpiece after finishing.

Further, the roughness of the surface line of the finished blade body is controlled to be Ra3.0 mu m-Ra1.0 mu m in the step S3, the thickness of a recast layer on the machined surface is 0.002 mm-0.01 mm, and the finish machining should reserve 0.01 mm-0.05 mm of single-side process allowance for the subsequent abrasive grain finishing.

Further, the air inlet side and the air outlet side are processed in step S4 by using forming electrodes with different structures, respectively, and the working surface of the forming electrode is conformed to the target shape of the surface to be processed on the corresponding air inlet/outlet side and is offset by an average discharge gap. The fine machining sequence of the air inlet (outlet) edges of different blades is determined according to the same clockwise direction, namely, when one air inlet (outlet) edge is machined, the blade disc is rotated by a certain angle around the central axis clockwise (or anticlockwise) to realize the position matching of the adjacent air inlet (outlet) edge and the electrode, and then the machining is continued until the fine machining of all the air inlet (outlet) edges is completed.

Further, the allowance of the single-side process of the flow channel between the leaves of the leaf disc after polishing is 0.01 mm-0.05 mm in the abrasive particle flow process in the step S5, the line roughness of the whole flow channel between the leaves after finishing is controlled to be Ra0.8 mu m-Ra0.4 mu m, and a recast layer on the processed surface is thoroughly removed.

Further, the abrasive flow polishing described in step S5 requires a guide ring to avoid the dimensional accuracy of the blade air inlet/outlet edge from being out of tolerance due to over-polishing during the abrasive flow processing. The guide ring comprises an air inlet side guide ring and an air exhaust side guide ring, and the details are as follows:

the flow guide rings are made of carbon steel or stainless steel, each flow guide ring is composed of a hollow disc and a plurality of uniformly distributed spokes with rectangular cross sections on the outer circular surface of the hollow disc, and the rectangular cross section side lines of the spokes are correspondingly parallel to the longitudinal cross section side line of the hollow disc.

The number of the spokes of the guide ring is the same as that of the blades to be processed on the blade disc, and the outer diameter of the hollow cylinder of the guide ring at the air inlet (exhaust) edge is 0-1.0 mm smaller than the outer diameter of the circle of the upper (lower) end face of the positioning wheel disc. The air inlet (exhaust) edge guide ring and the positioning wheel disc are coaxially arranged in the assembly, and the lower (upper) end surface of the air inlet (exhaust) edge guide ring is respectively attached to the upper (lower) end surface of the positioning wheel disc. Spokes on the air inlet (exhaust) edge guide ring and blades are arranged in one-to-one correspondence with the air inlet (exhaust) edges, the guide ring and the positioning wheel disc realize angular positioning and radial positioning through a plurality of axial positioning pins, and axial positioning is realized through the joint of the tenon side plane and the corresponding end face of the positioning wheel disc.

The width of the rectangular section of each air inlet (exhaust) edge guide ring spoke is 2.0-5.0 mm, the shape of the central axis of each spoke in the length direction is respectively the same as the shape of the central line of the corresponding air inlet (exhaust) edge of the blade, the length of each air inlet (exhaust) edge guide ring spoke is 1.0-3.0 mm larger than that of the corresponding air inlet (exhaust) edge of the blade, and the tail end of each spoke extends out of the blade tip by 0.5-2.0 mm.

After the guide ring and the blade disc are assembled, the central axis of the spoke on the air inlet (exhaust) edge guide ring is parallel to the central line of the air inlet (exhaust) edge of the corresponding blade, the horizontal distance between the central axis and the central line is 0-2.5 mm, and the vertical distance between the bottom surface of the spoke on the air inlet (exhaust) edge guide ring and the central line of the air inlet (exhaust) edge is 2.0-5.0 mm.

Further, the cleaning in step S6 includes sequentially performing high-pressure gas blowing, ultrasonic cleaning with a cleaning agent, water jet cleaning, and absolute ethyl alcohol soaking.

The invention has the beneficial effects that:

1) the forming processing of the blade body and the air inlet/outlet edge is ensured by adopting an electric spark processing technology, the tool loss is small, the processing precision is high, the processing stability is good, and the product yield is high.

2) The surface quality of the blade body and the air inlet/outlet edge is ensured by adopting an abrasive flow processing technology, the processing accessibility is good, the processing stability is good, and the processing precision of the free-form surface is high.

3) Compared with the abrasive belt grinding technology of single-blade processing, the abrasive flow processing technology can realize simultaneous polishing of a plurality of blades on one device, so that the processing efficiency is high.

Drawings

Fig. 1 is a schematic structural diagram of an aircraft engine compressor working blade to which the invention is applied.

FIG. 2 is a schematic view of a locating disk for use in assembly with compressor rotor blades in accordance with the present invention.

FIG. 3 is a schematic view of an assembled blisk of compressor working blades and a retention disk for use with the present invention.

Fig. 4 is a schematic view of the rough electrode spark machining and machining process of the present invention.

FIG. 5 is a schematic view of a blade spark erosion finishing electrode and process for use with the present invention.

FIG. 6 is a schematic view of a leading edge finishing electrode and process for use with the present invention.

Fig. 7 is an assembly schematic view of a special tool clamp for abrasive flow machining applied by the invention.

FIG. 8 is a surface topography and profile of a blade after spark finishing in accordance with an embodiment of the present invention.

FIG. 9 is a surface and profile of a blade after abrasive flow finishing in accordance with an embodiment of the present invention.

In the figure: 1-blade tip, 2-exhaust edge, 3-air inlet edge, 4-tenon, 5-mortise, 6-positioning wheel disc, 7-electric spark machine tool spindle, 8-group electrode, 9-blade body finish machining electrode, 10-electrode working surface, 11-air inlet edge finish machining electrode, 12-air inlet edge guide ring, 13-exhaust edge guide ring and 14-air inlet edge guide ring spoke.

Detailed Description

The present invention will now be described in further detail with reference to specific examples, which are intended to be illustrative, but not limiting, of the invention.

As shown in fig. 1-9.

A combined machining method of electric spark and abrasive flow for working blades of a compressor takes a certain aero-engine compressor as an example, and a blade disc of the aero-engine compressor is formed by assembling 20 blades and a wheel disc. The material of the working blade of the gas compressor with the dovetail-shaped circular arc tooth tenon is TC11, the structure is shown in figure 1, the surface accuracy of the processed blade is required to be +/-0.04, the fillet radius of the air inlet edge 3 and the air outlet edge 2 is 0.2 mu m, the surface line roughness of the blade is required to be Ra0.8 mu m, and the tenon 4 is processed. The processing scheme is as follows:

and step S1, assembling all 20 blades with the tenons processed and the positioning wheel disc 6 with the mortises 5 processed by numerical control milling into a complete blade disc. Fig. 2 shows the positioning disk used, milled using 304 stainless steel, with 20 mortises, each mortise 5 being a clearance fit after assembly with the tenon 4 of the blade, fig. 3 shows the assembled blisk.

In step S2, the grouped electrodes 8 are used to perform rough electric discharge machining on the blade bodies of all the blades in sequence on an electric discharge machining machine. As shown in fig. 4, which is a schematic diagram of rough machining of grouped electrodes by electric discharge and a machining process, the grouped electrodes are composed of 10 rough machining electrodes, the rough machining electrodes are uniformly distributed on the end face of the mounting plate, all the electrodes participate in rough machining of the blade body at the same time, and low-frequency vibration is applied to the electrodes by a machine tool during machining. 20 blades need two sets of processing to be completed, after the first set of blades are processed, the blade disc is rotated by 180 degrees clockwise around the central shaft, the second set of blades are processed continuously, and the rough machining of all the blades can be completed through the two sets of processing.

And step S3, sequentially carrying out electric spark finish machining on the blade bodies of all the blades by using the formed electrodes. As shown in FIG. 5, the electric spark finish machining electrode for the blade body and the machining process are schematically illustrated, the blade body is divided into two areas, namely a blade basin area and a blade back area, different finish machining electrodes 9 and the same electric gauge are adopted, the peak current is 17A, and the pulse width is 12.8 mu s. The processing sequence of the leaf pots (or leaf backs) is as follows (the numbers represent the leaf pots (or leaf backs) with successively numbered blades in the counter-clockwise direction): 1. 11, 20, 10, 19, 9, 18, 8, 17, 7, 16, 6, 15, 5, 14, 4, 13, 3, 12, 2. After finishing the blade body, the surface appearance and the profile appearance of the blade are shown in fig. 8, and it can be seen from the figure that the discharge pits are fully distributed on the processing surface, an obvious recast layer can be seen on the profile, and the surface line roughness Ra1.573 μm and the recast layer thickness about 3.61 μm are obtained by measurement. The margin of the single-side process reserved for abrasive particle flow finishing after the fine processing of the blade body is about 0.04 mm.

In step S4, the discharge/inlet edges of all the blades are subjected to spark finish machining in sequence using the formed electrodes. As shown in fig. 6, which is a schematic view of the inlet edge finishing electrode and the machining process, the exhaust edge finishing electrode has the same structure as the inlet edge electrode 11.

And step S5, performing parallel polishing on all the inter-leaf flow channels of the leaf disc by adopting an abrasive flow finishing process. The abrasive particle flow finishing processing adopts 36-mesh silicon carbide abrasive, the working pressure is 150bar, a bidirectional circulation processing mode is adopted, the abrasive consumption of a single circulation is 4L, and the total processing time is 72 min.

Fig. 7 is a schematic view of an abrasive flow machining tool holder. The guide rings comprise an air inlet side guide ring 12 and an air outlet side guide ring 13 which are made of 304 stainless steel and have the same structure and size. The width of the rectangular section of the air inlet (exhaust) side guide ring spoke 14 is 2.0mm, and the length of the spoke is 1.5mm larger than that of the air inlet (exhaust) side of the corresponding blade. After the guide ring and the blade disc are assembled, the tail ends of the spokes extend out of the blade tips by 1.0mm, the horizontal distance between the central axis of each spoke and the central line of the air inlet (exhaust) edge of the corresponding blade is 0mm, and the vertical distance between the bottom surface of each spoke on the guide ring of the air inlet (exhaust) edge and the central line of the air inlet (exhaust) edge is 2.0 mm.

And step S6, detaching the blade disc from the abrasive flow machine tool, detaching, cleaning and drying each blade of the blade disc, and carrying out subsequent detection. Fig. 9 shows the surface topography and profile of the blade after the abrasive flow finishing process. As can be seen from the figure, the electric spark pits on the surface of the blade after the finishing process disappeared, the surface showed regular grinding lines, the line roughness Ra was about 0.308 μm, and no recast layer structure was seen in the cross-sectional view, so that the recast layer was completely removed. The surface shape precision of the blade is measured by a three-coordinate measuring instrument, the precision is +/-0.03, and the requirement of a drawing is met. The fillet of the air inlet/outlet edge of the blade is measured by a fillet gauge, and the dimensional accuracy meets the requirements of drawings.

It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.

The present invention is not concerned with parts which are the same as or can be implemented using prior art techniques.