A multi-station fixture and processing method for machining through mounting holes of hollow blades

Abstract

A multi-station fixture and processing method for machining through holes of hollow blades, belonging to the technical field of machining of turbine guide blades of aero-engines, including a bottom plate. On both sides of the upper surface of the bottom plate, there are columns for installing bridge-type pressing supports. The top of the columns is installed with bridge-type pressing supports through stepped screws. On the upper surface of the bottom plate, an upper flange positioning block and a lower flange positioning block are installed through screws. A tool setting block is installed on the bottom plate near the upper flange positioning block. A radial pressing block assembly is installed on the top of the lower flange positioning block, and pressing assemblies are installed on the tops of both side walls of the lower flange positioning block. By studying the internal cavity plugging material and the profiling plugging scheme, the present invention solves the influence of secondary foreign objects generated by the conventional plugging scheme and eliminates the possibility of metal chips entering the internal cavity. By studying the fixture design scheme to avoid tool interference and spindle interference of the equipment, the interference problem of machining multiple high-precision holes in one clamping is solved, and the machining efficiency and machining precision of the parts are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of machining of turbine guide vanes for aeroengines, and particularly relates to a multi-station fixture and a machining method for machining through mounting holes of hollow vanes. Background Art

[0002] Turbine guide vanes are key aerodynamic components of aeroengines. In recent years, in order to improve the overall performance of the engine, reduce airflow losses, and improve structural strength, various multi-piece integral casting structures have emerged in the family of turbine guide vanes. Such vanes not only have complex casting processes, but also extremely high machining technical difficulties for related parts. Among them, the vane structure is a multi-piece hollow integral casting, and there are multiple mounting holes penetrating the hollow cavity on the upper and lower flange plates. As Figure 1 shown, and the positional accuracy requirements of the mounting holes are relatively high. At the same time, during the machining process, it is necessary to protect the inner cavity to prevent metal substances from entering the inner cavity. The traditional drilling method with wax pouring protection cannot be used for machining, which restricts the research and development progress of new engines. Summary of the Invention

[0003] The purpose of the present invention is to provide a multi-station fixture and a machining method for machining through mounting holes of hollow vanes, which successfully complete the inner cavity protection and machining of the through mounting holes of the integral multi-piece guide vanes of a certain aircraft, filling a technical gap in the domestic machining field of hollow turbine vanes.

[0004] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0005] A multi-station fixture for machining through mounting holes of hollow vanes, including a bottom plate. On both sides of the upper surface of the bottom plate, there are columns for installing bridge-type pressing supports. The top of the columns is installed with bridge-type pressing supports through stepped screws. On the upper surface of the bottom plate, an upper flange plate positioning block and a lower flange plate positioning block are installed through screws. A tool setting block is installed on the bottom plate close to the upper flange plate positioning block. A radial pressing block assembly is installed on the top of the lower flange plate positioning block, and pressing assemblies are installed on the top of both side walls of the lower flange plate positioning block.

[0006] A threaded hole is opened in the middle of the bridge-type pressing support. A jacking screw is screwed in the threaded hole. An axial pressing block is screwed at the bottom of the jacking screw. And a cylindrical pin is installed between the axial pressing block and the jacking screw to limit the rotational freedom of the axial pressing block.

[0007] The pressing assembly includes support plates installed on both end side walls of the lower flange plate positioning block. Adjusting screws are symmetrically installed on the support plates. A circumferential pressing block is installed at the end of the adjusting screw.

[0008] The radial pressing block assembly includes a radial pressing block, which is installed in the large-diameter hole of the counterbore at the top of the lower edge plate positioning block. A hexagonal socket head cap screw passes through the central hole of the radial pressing block and is screwed into the small-diameter threaded hole of the counterbore. A compression spring sleeved on the hexagonal socket head cap screw is installed between the radial pressing block and the large-diameter hole of the counterbore.

[0009] A multi-station fixture for machining the through mounting holes of hollow blades and a machining method for machining the through mounting holes of hollow blades are adopted, including the following steps:

[0010] Step 1, use a stainless steel rod to press the lower edge plate plugging block into the lower edge plate hole.

[0011] Step 2, use a profiling pressing rod to press the upper edge plate plugging block into the profiling hole, and use a file to compact the edge. The pressing depth should be flush with the profiling hole.

[0012] Step 3, after the upper edge plate plugging block and the lower edge plate plugging block are installed, let the part stand for 20 - 30 minutes.

[0013] Step 4, install the blade on the multi-station fixture, install the blade according to the reference plane specified in the technical document, lay the circumferential pressing block of the blade body flat against the blade body of the part, and then slowly tighten the pressing bolt to ensure the stability of the part clamping.

[0014] Step 5, adopt a multi-coordinate system machining method to machine the mounting hole system, start the machining program for trial machining, and adjust the position of each coordinate system according to the trial machining situation to ensure the positional accuracy of the mounting hole system of the part.

[0015] Step 6, clean the burrs generated on the surface of the part after machining.

[0016] Step 7, use compressed air to clean the metal chips remaining on the surface of the part. During the cleaning process, adjust the pressure of the compressed air to avoid blowing out the memory cotton from the inner cavity of the part due to excessive pressure.

[0017] Step 8, use a crochet hook to take out the upper edge plate plugging block and the lower edge plate plugging block, and promptly clean the oil stain on the surfaces of the upper edge plate plugging block and the lower edge plate plugging block, and store them after natural drying.

[0018] The lower edge plate plugging block and the upper edge plate plugging block described in Step 1 are made of memory cotton material, and the upper edge plate plugging block and the lower edge plate plugging block are made into a profiling structure to facilitate the installation of the plugging block, that is, the lower edge plate plugging block is made into a cylindrical plugging block, and the upper edge plate plugging block is made into a cavity-shaped plugging block.

[0019] The beneficial technical effects of the present invention are:

[0020] 1) By studying the inner cavity plugging material and the profiling plugging scheme, the present invention solves the influence of secondary foreign matters generated by the conventional plugging scheme and eliminates the possibility of metal chips entering the inner cavity.

[0021] 2) By studying the fixture design scheme to avoid tool interference and spindle interference of the equipment, the present invention solves the interference problem of machining multiple high-precision holes in one clamping, and improves the machining efficiency and machining accuracy of parts.

[0022] 3) By studying the multi-coordinate system machining scheme, the present invention solves the problem of small deviations in the position accuracy of holes in the same coordinate system, and further improves the efficiency and quality stability of hole system machining.

[0023] 4) According to this technical scheme, the inner cavity foreign matter protection and high-precision hole multi-position machining of the through holes of the aero-engine multi-piece integral cast hollow blades are carried out. The position accuracy of the hole system reaches 0.06, and the qualified rate is increased from 60% to more than 95%. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Schematic structural diagram of the hollow blade of the present invention;

[0025] Figure 2 Schematic structural diagram of the lower edge plate plugging block of the present invention;

[0026] Figure 3 Schematic structural diagram of the upper edge plate plugging block of the present invention;

[0027] Figure 4 Front view sectional view of the multi-station fixture for machining the through mounting holes of the hollow blade of the present invention;

[0028] Figure 5 Side view sectional view of the multi-station fixture for machining the through mounting holes of the hollow blade of the present invention;

[0029] 1 - Base plate, 2 - Upper edge plate positioning block, 3 - Lower edge plate positioning block, 5 - Axial pressing block, 6 - Bridge-type pressing support, 8 - Pillar, 9 - Tool setting block, 10 - Step screw, 12 - Tightening screw, 15 - Compression spring, 16 - Hexagon socket head cap screw, 21 - Radial pressing block, 22 - Support plate, 23 - Circumferential pressing block, 24 - Upper edge plate plugging block, 25 - Lower edge plate plugging block. DETAILED DESCRIPTION OF THE INVENTION

[0030] The present invention will be further described in detail below with reference to the drawings and embodiments.

[0031] As Figure 4 and Figure 5As shown in the figure, a multi-station fixture for machining the through mounting holes of a hollow blade includes a bottom plate 1. On both sides of the upper surface of the bottom plate 1, there are columns 8 for mounting a bridge-type pressing support 6. The top of the column 8 is mounted with a bridge-type pressing support 6 through a stepped screw 10. The upper surface of the bottom plate 1 is mounted with an upper flange positioning block 2 and a lower flange positioning block 3 by screws. A tool setting block 9 is mounted on the bottom plate 1 near the upper flange positioning block 2. A radial pressing block assembly is mounted on the top of the lower flange positioning block 3, and pressing assemblies are mounted on the top of both side walls of the lower flange positioning block 3.

[0032] A threaded hole is provided in the middle of the bridge-type pressing support 6. A top screw 12 is screwed in the threaded hole. An axial pressing block 5 is screwed at the bottom of the top screw 12, and a cylindrical pin is installed between the axial pressing block 5 and the top screw 12 to limit the rotational freedom of the axial pressing block 5.

[0033] The pressing assembly includes support plates 22 mounted on both end side walls of the lower flange positioning block 3. Adjusting screws are symmetrically mounted on the support plates 22, and a circumferential pressing block 23 is mounted at the end of the adjusting screw.

[0034] The radial pressing block assembly includes a radial pressing block 21. The radial pressing block 21 is mounted in the large-diameter hole of the counterbore on the top of the lower flange positioning block 3. A hexagonal socket head cap screw passes through the central hole of the radial pressing block 21 and is then screwed into the small-diameter threaded hole of the counterbore. A compression spring 15 sleeved on the inner hexagonal socket head cap screw 16 is installed between the radial pressing block 21 and the large-diameter hole of the counterbore.

[0035] The machined parts of the hollow blade are all on the flange side. To avoid tool interference during machining, the pressing part should reasonably avoid the flange position. Since the overall size of the blade is small, choosing to press at the traditional position cannot meet the machining requirements. Therefore, when designing the pressing, the blade body part that can bear the pressing force is selected as the pressing position to ensure the clamping stability of the blade. To prevent the blade body from being pressed, a metal material with a lower hardness should be selected for the contact part.

[0036] Since the assembly holes of the blade are in symmetric positions, the fixture needs to rotate symmetrically along the Y axis during the machining process, and at the same time, it needs to rotate 30° and 90° in the X-axis direction. Therefore, it is necessary to study that the part does not interfere with the machine tool spindle after rotation, and the fixture body needs to be adjusted in the height direction to meet the machining height.

[0037] A processing method for machining the through mounting holes of a hollow blade using a multi-station fixture for machining the through mounting holes of a hollow blade includes the following steps:

[0038] Step 1, as Figure 2As shown in the figure, press the lower edge plate plugging block 25 made of memory foam material into a small cylinder with a diameter within 5 mm, and use a stainless steel rod with a diameter of 5 mm to press the lower edge plate plugging block 25 into the lower edge plate hole. The pressing depth is 3 mm from the hole edge;

[0039] Step 2, as Figure 3 shown in the figure, press the upper edge plate plugging block 24 made of memory foam material into a small block with a thickness within 3 mm, use a profiling pressing rod to press the upper edge plate plugging block 24 into the shaped hole, and use a file to compact it at the edge. The pressing depth is flush with the shaped hole; After the plugging block made of memory foam material enters the inner cavity of the blade, using the slow resilience of the memory foam, before plugging the inner cavity, compress the memory foam, and after putting it into the cavity, after a period of time, the memory foam rebounds to its original state, completely plugging the entire inner cavity wall, effectively preventing metal chips from entering the inner cavity;

[0040] Step 3, after the upper edge plate plugging block 24 and the lower edge plate plugging block 25 are installed, let the part stand for 30 minutes;

[0041] Step 4, install the blade on the multi-station fixture, install the blade according to the reference plane specified in the technical document. The upper and lower edge plate planes of the blade are respectively fitted with the upper edge plate positioning block 2 and the lower edge plate positioning block 3 of the fixture, the outer arc is fitted with the arc on the upper edge plate positioning block 2, and the left side of the boss on the blade is fitted with the groove on the upper edge plate positioning block 2. Tighten the radial pressing block 21, the axial pressing block 5, and the circumferential pressing block 23 in sequence to ensure the stability of the part clamping;

[0042] Step 5, start the machining program for trial machining, and adjust the position of the entire coordinate system according to the trial machining situation to ensure the positional accuracy of the part hole system;

[0043] Specifically: in terms of ensuring the quality of single installation hole machining and the overall machining efficiency, machining is carried out through a multi-coordinate system machining method, that is, each installation hole corresponds to a coordinate system, ensuring that the machining positions of each installation hole system meet the process technical requirements under different machining conditions, so as to achieve the effect of improving machining efficiency and machining quality;

[0044] In the environment of multi-coordinate system machining, each high-precision installation hole system corresponds to a different machining coordinate system, and the machining accuracy is adjusted according to the detection results. During the adjustment process, the problem of positional accuracy detection error of different holes on the same coordinate system is avoided; Due to the relatively compact structure of the part, it is necessary to use high-precision measuring equipment to measure the coordinate system uniformly to improve machining and detection efficiency;

[0045] Step 6, clean the burrs generated on the part surface after machining;

[0046] Step 7, use compressed air to clean the metal chips remaining on the surface of the parts. During the cleaning process, adjust the pressure of the compressed air to avoid blowing out the memory cotton from the inner cavity of the parts due to excessive pressure;

[0047] Step 8, use a crochet hook to take out the upper edge plate plug 24 and the lower edge plate plug 25, and promptly clean the oil stains on the surface of the memory cotton, and store it after natural drying.

[0048] Due to the structural characteristics of the parts, the inner cavity of the blade belongs to a horn-shaped structure with multiple small columns inside. Once foreign objects enter, it is very difficult to take them out. Therefore, it is necessary to study an inner cavity protection material that is convenient to enter the cavity, has no pollution to the blade itself, and is easy to take out. At the same time, it is necessary to fully consider that it cannot fall off during the fluid scouring in the processing process, so as to achieve the effect of fully protecting the inner cavity. Therefore, the lower edge plate plug 25 and the upper edge plate plug 24 are made of memory cotton material. After installing the lower edge plate plug 25 and the upper edge plate plug 24 into the inner cavity of the blade, using the slow resilience of the memory cotton, before blocking the inner cavity, compress the memory cotton and put it into the cavity. After a period of time, the memory cotton rebounds to its original state, completely blocking the entire inner cavity wall, effectively preventing metal chips from entering the inner cavity.

[0049] According to the inner cavity structure, the upper edge plate plug 24 and the lower edge plate plug 25 are made into a profiling structure, which can facilitate the installation of the plug and improve the plugging efficiency of the blade. According to the part structure, the lower edge plate plug 25 is made into a cylindrical plug, and the upper edge plate plug 24 is made into a cavity body.

Claims

1. A multi-station fixture for machining the through mounting holes of a hollow blade, and a machining method for machining the through mounting holes of the hollow blade. The multi-station fixture includes a bottom plate. On both sides of the upper surface of the bottom plate, there are columns for installing a bridge-type pressing support. The top of the column is installed with a bridge-type pressing support through a stepped screw. The upper edge plate positioning block and the lower edge plate positioning block are installed on the upper surface of the bottom plate through screws. A tool setting block is installed on the bottom plate near the upper edge plate positioning block. A radial pressing block assembly is installed on the top of the lower edge plate positioning block. Pressing components are installed on the tops of both side walls of the lower edge plate positioning block. It is characterized in that It includes the following steps: Step 1, press the lower edge plate plugging block into the lower edge plate hole using a stainless steel rod. Step 2, press the upper edge plate plugging block into the shaped hole using a profiling pressing rod, and use a file to compact it at the edge. The pressing depth should be flush with the shaped hole. The lower edge plate plugging block and the upper edge plate plugging block described in Step 1 and Step 2 are made of memory cotton material, and the upper edge plate plugging block and the lower edge plate plugging block are made into a profiling structure to facilitate the installation of the plugging block. That is, the lower edge plate plugging block is made into a cylindrical plugging block, and the upper edge plate plugging block is made into a cavity-shaped plugging block. Step 3, after the upper edge plate plugging block and the lower edge plate plugging block are installed, let the part stand still for 20 - 30 minutes. Step 4, install the blade on the multi-station fixture, lay the circumferential pressing block of the blade body flat against the blade body of the part, and then slowly tighten the pressing bolt to ensure the stability of the part clamping. Step 5, adopt a multi-coordinate system machining method to machine the mounting hole system, start the machining program for trial machining, and adjust the coordinate system position according to the trial machining situation to ensure the positional accuracy of the mounting hole system of the part. Step 6, clean the burrs generated on the surface of the part after machining. Step 7, use compressed air to clean the metal chips remaining on the surface of the part. During the cleaning process, adjust the pressure of the compressed air to avoid the upper edge plate plugging block / lower edge plate plugging block being blown out of the inner cavity of the part due to excessive pressure. Step 8, use a crochet needle to take out the upper edge plate plugging block and the lower edge plate plugging block, and promptly clean the oil stains on the surfaces of the upper edge plate plugging block and the lower edge plate plugging block, and store them after natural drying.

2. The processing method for machining the through mounting holes of the hollow blade using the multi-station fixture according to claim 1, characterized in that: A threaded hole is opened in the middle of the bridge-type pressing support. A jacking screw is screwed into the threaded hole. An axial pressing block is screwed to the bottom of the jacking screw. And a cylindrical pin is installed between the axial pressing block and the jacking screw to limit the rotational freedom of the axial pressing block.

3. A multi-station fixture for machining the through mounting holes of a hollow blade, and a machining method for machining the through mounting holes of the hollow blade, characterized in that: The pressing component includes support plates installed on both end side walls of the lower edge plate positioning block. Adjusting screws are symmetrically installed on the support plates. A circumferential pressing block is installed at the end of the adjusting screw.

4. A machining method for machining the through mounting holes of the hollow blade using the multi-station fixture according to claim 1, characterized in that: The radial pressing block assembly includes a radial pressing block. The radial pressing block is installed in the large-diameter hole of the counterbore on the top of the lower edge plate positioning block. A hexagonal socket head cap screw passes through the central hole of the radial pressing block and is screwed into the small-diameter threaded hole of the counterbore. A compression spring sleeved on the hexagonal socket head cap screw is installed between the radial pressing block and the large-diameter hole of the counterbore.

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