A device and method for machining the inlet and exhaust edges of a precision-forged blade

Abstract

The application discloses a kind of precision forging vane inlet and exhaust edge processing device and method, processing device is mainly composed of adapter plate, bottom plate, compression plate, leaf basin compression block, back support block, elastic support block and compression support block.It is processed to the inlet and exhaust edge of precision forging vane using fixed blade body state milling, self-adaptive grinding, vibration polishing mode.The application avoids the difficulty in processing caused by the position degree of precision forging vane blade body, torsion and other factors, solves the problems of low precision forging vane polishing pass rate and poor consistency caused by manual blind polishing, shortens the processing cycle of parts.The application also solves the problem that precision forging vane inlet and exhaust edge is not easy to clamp during processing, and solves the problem that precision forging vane inlet and exhaust edge is easily deformed by clamp clamping force and tool cutting force during processing through structure design and reasonable arrangement of compression position.

Description

Technical Field

[0001] The present invention relates to a device and method for machining the inlet and exhaust edges of precision forging blades of aero-engines, belonging to the technical field of machining precision forging blades in the production and manufacturing of aero-engines. Background Art

[0002] Compared with ordinary die-forged blades, precision forging blades of aero-engines have the characteristics of high profile dimension accuracy, high material utilization rate, etc. At the same time, they have good metal flow lines and metallographic structures, which can effectively improve the performance and service life of the blades and reduce production costs.

[0003] As Figure 1 and Figure 2 shown, the profile of the blade body of the precision forging blade of the aero-engine is directly formed by precision forging. However, the inlet and exhaust edges are in the direction of the forging flash and the discharge of excess material, and the design dimensions cannot be directly achieved, and there is still a margin of 2 mm. During the machining process, it is necessary to machine the inlet and exhaust edges of the blade body. Since the blade body has reached the designed required dimensions, there are certain differences in the position and torsion of different blades, and it is impossible to directly use a fixed numerical control program for machining.

[0004] At present, the steps of manually polishing the inlet and exhaust edges of the blade are as follows: first, blindly polish once, then measure the blade with a coordinate measuring machine. According to the measurement results, use a marker pen to mark the out-of-tolerance positions on the blade and mark the out-of-tolerance amount, and then manually polish again. After polishing, measure with a coordinate measuring machine again until it is qualified. The time for one round of measurement, marking, and polishing is approximately 10 to 15 minutes per piece. Generally, 4 to 6 rounds of repeated measurement and polishing are required to machine a qualified blade. The average time for polishing the inlet and exhaust edges of each blade is about 1 hour, which is greatly affected by the skill level of the polishing workers. Due to the large spatial distortion and very thin relative thickness (the minimum tip equivalent radius is less than 0.1 mm) of the inlet and exhaust edges of the blade, the direct manual grinding method is prone to problems such as large shape errors, poor consistency, and high scrap rates. In addition, the shape accuracy of the inlet and exhaust edges of the blade is more important than the dimensional accuracy. Manual grinding and polishing are prone to shape accuracy errors, resulting in product rejection. Summary of the Invention

[0005] The present invention aims to provide a device and method for machining the inlet and exhaust edges of precision forging blades, obtain the precise shape and dimensional accuracy of the inlet and exhaust edges on the precision forging blades, ensure the machining consistency and qualification rate of the precision forging blades, improve the machining efficiency, and solve the deformation problem in the machining process.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A device for machining the inlet and exhaust edges of precision forging blades, comprising:

[0008] A blade basin clamping block is pressed against the blade basin profile of a precision forged blade. The surface of the blade basin clamping block includes a clamping surface, the contour of which is consistent with the theoretical blade basin profile of the precision forged blade.

[0009] A blade back support block is used to support the blade back profile of a precision forged blade. The surface of the blade back support block includes a support surface, the outline of which is consistent with the theoretical blade back profile of the precision forged blade.

[0010] A clamping plate is connected to the blade basin clamping block and applies a force to the blade basin clamping block so that the clamping surface of the blade basin clamping block is in close contact with the blade basin profile of the precision forged blade.

[0011] The two elastic support blocks are respectively set on the left and right sides of the blade back support block. The upper end of the elastic support block contacts one side of the blade back of the precision forged blade, and the contact point is located on the left and right sides of the support surface of the blade back support block. The height of the elastic support block is adjustable and has a height locking function.

[0012] The two clamping support blocks are located on the left and right sides of the blade basin clamping block, respectively, and the upper end of the clamping support block is connected to the clamping plate.

[0013] As one solution, the precision forging blade inlet and outlet edge processing device also includes an adapter plate and a base plate. The adapter plate is connected to the machine tool's rotary shaft. The adapter plate includes a disc-shaped base. A support beam extends from the center of the base along the axis of the machine tool's rotary shaft. The base plate is mounted on the support beam. The upper end of the base plate has a mounting plane parallel to the machine tool's rotary shaft. The lower ends of the blade back support block, elastic support block, and clamping support block are fixed on the mounting plane.

[0014] As one embodiment, the elastic support block includes a support with a blind hole at the upper end of the support. A support block is slidably connected inside the blind hole, and the upper end of the support block forms the upper end of the elastic support block. A spring is provided between the lower end of the support block and the bottom of the blind hole. A threaded hole is provided on the side of the support, and a locking screw is provided inside the threaded hole, with the end of the locking screw pointing towards the support block.

[0015] A method for machining the inlet and outlet edges of precision forged blades, employing the aforementioned precision forged blade inlet and outlet edge machining device, and comprising the following steps:

[0016] S1. Clamp and position the precision forged blade. Place a shim on the upper end of the blade back support block, then place the precision forged blade on the shim. Press the precision forged blade from one side of the blade basin until the blade back of the precision forged blade compresses the elastic support block a certain distance. Then lock the height of the elastic support block. Remove the shim. Drive the blade basin pressing block towards the blade basin of the precision forged blade through the pressing plate until the blade basin of the precision forged blade is pressed. Lock the position of the pressing plate.

[0017] S2, milling the inlet and outlet edges of the precision forged blades, leaving machining allowance for subsequent grinding;

[0018] S3, Grinding the inlet and outlet edges of the precision forged blade. An adaptive machining method is used to compare the actual model and the theoretical model to obtain a new benchmark and plan a new grinding trajectory. The grinding of the inlet and outlet edges of the precision forged blade is completed according to the new grinding trajectory.

[0019] S4, Vibration finishing: The precision forged blades after S3 grinding are vibrated and finished using a vibration finishing machine, which turns the small pointed tips of the inlet and outlet edges of the precision forged blades into rounded tips.

[0020] Furthermore, in S1, the thickness of the shim is such that the precision-forged blade located between the two elastic support blocks only undergoes elastic deformation when pressed.

[0021] Furthermore, in S2, a CNC milling process is used, and the air intake edge is milled first, followed by the air exhaust edge.

[0022] Furthermore, S3 specifically includes the following steps:

[0023] S31, Measure the actual allowance of the inlet and outlet edges of the precision forged blade to obtain the spatial orientation and actual shape of the precision forged blade;

[0024] S32, reference registration, uses the ICP algorithm to spatially register the precision forged blade with the measurement data in S31, obtains the optimal spatial coordinate system of the precision forged blade and adjusts the spatial attitude of the blade;

[0025] S33, Model Reconstruction: Under the optimal coordinate system obtained in S32, based on the theoretical digital model of the precision forged blade and the measurement data in S31, the adaptive machining model of the inlet and outlet sides of the precision forged blade is reconstructed, and the parameter mapping relationship between the theoretical model and the reconstructed model of the precision forged blade is established.

[0026] S34, adaptive grinding process, adaptively adjusts the grinding trajectory according to the parameter mapping relationship in S33, and adaptively grinds the inlet and outlet edges of precision forged blades.

[0027] Alternatively, in S31, an optical scanning detection method is used to measure the actual allowance of the precision forged blade. The measurement locations include the allowance at the inlet and outlet edges of the precision forged blade, as well as the allowance within a certain distance from the leading and trailing edges of the precision forged blade.

[0028] Alternatively, in S34, a flexible fiber grinding wheel is used for grinding, with a wheel diameter of Φ300mm, a grinding depth of 3mm to 5mm, and a grinding deflection angle of ±20°.

[0029] As an option:

[0030] In step S1, the gasket is a copper sheet with a thickness of 0.03 mm.

[0031] In S2, the reserved machining allowance is 0.3mm to 0.4mm, the milling tool is D6R3, the milling spindle speed is 2500r / min, and the feed rate is 500mm / min.

[0032] Compared with the prior art, the present invention has the following characteristics:

[0033] (1) This invention provides a new processing method for the intake and exhaust edges of precision forged blades. Instead of using traditional manual blind polishing, it adopts a method of "fixed blade state milling + adaptive grinding + vibration finishing". This avoids the processing difficulties caused by factors such as the position and torsion of the precision forged blade, and solves the problems of low polishing pass rate and poor consistency of precision forged blades caused by manual blind polishing, thus shortening the processing cycle of parts.

[0034] (2) This invention designs a special machining device for milling the inlet and outlet edges of precision forged blades, which solves the problem that the inlet and outlet edges of precision forged blades are not easy to clamp during the machining process. The special machining device solves the problem that the inlet and outlet edges of precision forged blades are easily deformed by the clamping force of the fixture and the cutting force of the tool during the machining process through the structural design that fits the curved surface of the part and the reasonable arrangement of the clamping position. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the component structure of the precision-forged blade in this invention;

[0036] Figure 2 This is a schematic diagram of the blade profile of the precision-forged blade in this invention;

[0037] Figure 3 This is a perspective view of the precision forging blade inlet and outlet edge processing device designed in this invention;

[0038] Figure 4 This is a flowchart of the adaptive grinding process for the intake and exhaust edges of the precision forged blades in this invention;

[0039] Figure 5 This is a schematic diagram of the adaptive grinding process of the intake and exhaust edges of the precision forged blade in this invention;

[0040] In the diagram, 1-adapter plate, 2-base plate, 3-pressure plate, 4-blade basin pressure block, 5-blade back support block, 6-elastic support block, and 7-pressure support block. Detailed Implementation

[0041] The present invention will be further described below with reference to specific embodiments, but it should not be construed as limiting the scope of the subject matter of the present invention to the following embodiments. All modifications, substitutions and alterations made based on ordinary technical knowledge and common practices in the art without departing from the above-described technical concept of the present invention are included within the scope of the present invention.

[0042] Figure 3 The invention demonstrates a precision forging blade inlet and outlet edge processing device, which mainly consists of a transfer plate 1, a base plate 2, a clamping plate 3, a blade basin clamping block 4, a blade back support block 5, an elastic support block 6, and a clamping support block 7.

[0043] The machining approach for the inlet and outlet edges of precision-forged blades in this invention is as follows:

[0044] (1) Fabrication of blade basin clamping block 4: Design the structure of blade basin clamping block 4 according to the theoretical profile of the blade basin of the precision forged blade, and fabricate blade basin clamping block 4 with the same theoretical profile of the blade basin as the precision forged blade.

[0045] (2) Fabrication of blade back support block 5: Design the structure of blade back support block 5 according to the theoretical profile of the blade back of the precision forged blade, and fabricate blade back support block 5 with the same theoretical profile of the blade back of the precision forged blade.

[0046] (3) Blank (forged blade blank) clamping and positioning: Place a 0.03mm thick copper sheet on the blade back support block 5. After the blade back direction of the forged blade is aligned with the blade back support block 5, lock the elastic support block 6. Then remove the copper sheet and press the blade basin clamping block 4 to ensure that the blade body of the forged blades with different positions and torsions are in the same state after clamping.

[0047] (4) Milling the air intake and exhaust edges: Use a computer and UG programming software to generate a fixed CNC machining program to machine the air intake and exhaust edges, leaving a allowance of 0.3mm to 0.4mm, which is reserved for subsequent grinding;

[0048] (5) Grinding the air intake and exhaust edges: The optical scanning measuring machine is used to detect and calculate the air intake and exhaust edge allowance to obtain the actual allowance; the adaptive machining method is used to compare the actual model and the theoretical model to obtain a new benchmark and plan the grinding trajectory (secondary correction), and the automated grinding process is completed according to the new grinding trajectory.

[0049] (6) Blade vibration finishing: The blades after grinding are vibrated and finished using a vibration finishing machine. The vibration finishing time is 30 min to 50 min.

[0050] Specifically, the machining method for the intake and exhaust edges of precision forged blades includes the following steps:

[0051] Milling the inlet and outlet edges of precision forged blades:

[0052] Step S1: Make blade basin clamping block 4: Machine blade basin clamping block 4 according to the theoretical profile of the precision forged blade blade basin to ensure that the blade basin is in a surface-fitting state with the blade when clamping, and the blade basin is clamped with uniform force.

[0053] Step S2: Fabricate blade back support block 5: Machin the blade back support block 5 according to the theoretical profile of the blade back of the precision forged blade to ensure that the blade back support is in a surface-to-surface contact state with the blade and that the blade back support is subjected to uniform force.

[0054] Step S3: Blank (Precision Forged Blade Blank) Clamping and Positioning: Before machining the precision forged blade, the machining device needs to be fixed to the machine tool's rotary shaft via the adapter plate 1 and the base plate 2. Before clamping the precision forged blade, place a copper sheet with a thickness of about 0.03mm on the blade back support block 5, then place the precision forged blade on the copper sheet. After pressing the blade with your hand or other tools, lock the height position of the elastic support blocks 6 on both sides, and then remove the copper sheet. Use the blade basin clamping block 4 to press the blade basin of the precision forged blade, and lock the clamping plate 3 (the clamping plate 3 and the clamping plate support block 7 are threadedly connected, and the height position of the clamping plate 3 on the clamping support block 7 is locked with a nut). At this time, since there is a 0.03mm gap between the precision forged blade body and the blade back support block 5, the precision forged blade fits against the blade back support block 5 through elastic deformation when clamping, which can ensure that blades with differences in position, torsion, etc. are in the same state after the machining device is clamped.

[0055] Step S4: Milling the intake and exhaust edges of the precision forged blade: Use a computer and UG programming software to generate a fixed CNC milling program (the fixed CNC milling program here is relative to the subsequent adaptive grinding) to machine the intake and exhaust edges. The machining process is divided into two stages: the first stage is milling the intake edge, and the second stage is milling the exhaust edge. When cutting, select the D6R3 tool, the spindle speed is 2500r / min, the feed rate F is set to 500mm / min, and leave a allowance of 0.3mm~0.4mm for the intake and exhaust edges, which is reserved for subsequent grinding.

[0056] The above-mentioned method of milling the inlet and outlet edges of the fixed precision forged blade can largely solve the problem of machining consistency caused by differences in blade position, torsion, and other factors. However, during the machining process, it may be affected by factors such as blade deformation and clamping errors, resulting in slight machining errors. Therefore, adaptive grinding is subsequently used for secondary correction to ensure high-precision, high-consistency, and high-efficiency machining of the inlet and outlet edges of the precision forged blade. The adaptive grinding process is as follows: Figure 4 As shown, the processing steps include the following:

[0057] Adaptive grinding process for precision forged blade inlet and outlet edges:

[0058] Step S5: Measurement of blade inlet and outlet margins: The actual margin of the precision forged blade is detected and calculated using methods such as optical scanning detection (including the margin of the inlet and outlet margins and the length of the blade body 1mm from the front and trailing edges) to obtain the spatial attitude and actual shape of the blade.

[0059] Step S6: Reference Registration: The ICP (Iterative Closest Point) registration algorithm is used to spatially register the blade and measurement data to obtain the optimal spatial coordinate system of the blade and adjust the spatial attitude of the blade; for details, please refer to "Zhai Fugang, Zhao Zhi, Cai Zhenhui, et al. Blank Registration Method Based on Blade Section Feature Parameters [J]. Electrical Discharge Machining & Die & Mold, 2023, (S1): 13-19+54." or any existing technology on ICP algorithm registration;

[0060] Step S7: Model Reconstruction: Under the optimal coordinate system determined in S6, based on the blade theoretical digital model and measurement data, reconstruct the blade inlet and outlet edge adaptive machining model, and establish the parameter mapping relationship between the blade theoretical model and the reconstructed model; for the specific process, refer to "Feng Yazhou, Ren Junxue, Liang Yongshou, et al. Multi-objective constraint geometric reconstruction optimization algorithm for precision forging blades [J]. Acta Aeronautica Sinica, 2018, 39(07):228-238." or any existing technology on blade machining model reconstruction or blade adaptive machining;

[0061] Step S8: Adaptive Grinding: The grinding trajectory is adaptively adjusted according to the parameter mapping relationship to adaptively process the blade inlet and outlet edges (with a tolerance of ±0.035mm in length 1mm from the leading and trailing edges). The grinding wheel used is a flexible fiber grinding wheel with a diameter of Φ300mm. The blade grinding depth is 3mm to 5mm, the grinding deflection angle is ±20°, and the pitch angle is generally determined according to the edge plate condition. A schematic diagram of adaptive grinding is shown below. Figure 5 As shown.

[0062] Step S9: Blade Vibration Finishing: The precision forged blades after grinding are vibrated and finished using a vibration finishing machine to change the small pointed ends of the inlet and outlet edges of the precision forged blades into rounded ends. The vibration finishing processing time is 30 min to 50 min.

[0063] Contents not described in detail in this specification are prior art known to those skilled in the art. Although illustrative specific embodiments of the invention have been described above to facilitate understanding by those skilled in the art, it should be understood that the invention is not limited to the scope of the specific embodiments. Various modifications are readily apparent to those skilled in the art as long as they fall within the spirit and scope of the invention as defined and determined by the appended claims, and all inventions utilizing the concept of this invention are protected.

Claims

1. A method for machining the intake and exhaust edges of precision-forged blades, characterized in that: A precision forging blade inlet and outlet edge machining device is adopted, and the machining device includes: A blade basin clamping block (4) is pressed against the blade basin profile of a precision forged blade. The surface of the blade basin clamping block (4) includes a clamping surface, and the outline of the clamping surface is consistent with the theoretical profile of the blade basin of the precision forged blade. The blade back support block (5) is used to support the blade back profile of the precision forged blade. The surface of the blade back support block (5) includes a support surface, and the outline of the support surface is consistent with the theoretical blade back profile of the precision forged blade. The clamping plate (3) is connected to the blade basin clamping block (4) and applies a force to the blade basin clamping block (4) so ​​that the clamping surface of the blade basin clamping block (4) is in close contact with the blade basin profile of the precision forged blade; Elastic support block (6), the two elastic support blocks (6) are respectively set on the left and right sides of the blade back support block (5). The upper end of the elastic support block (6) contacts one side of the blade back of the precision forged blade, and the contact point is located on the left and right sides of the support surface of the blade back support block (5). The height of the elastic support block (6) is adjustable and has a height locking function. The two clamping support blocks (7) are located on the left and right sides of the blade basin clamping block (4), and the upper end of the clamping support block (7) is connected to the clamping plate (3). The processing method includes the following steps: S1, clamp and position the precision forged blade, place a pad on the upper end of the blade back support block (5), then place the precision forged blade on the pad, press the precision forged blade from the blade basin side until the blade back of the precision forged blade compresses the elastic support block (6) a certain distance, lock the height of the elastic support block (6), remove the pad, drive the blade basin pressing block (4) towards the blade basin of the precision forged blade through the pressing plate (3) until the blade basin of the precision forged blade is pressed, and lock the position of the pressing plate (3). S2, milling the inlet and outlet edges of the precision forged blades, leaving machining allowance for subsequent grinding; S3, Grinding the inlet and outlet edges of the precision forged blade. An adaptive machining method is used to compare the actual model and the theoretical model to obtain a new benchmark and plan a new grinding trajectory. The grinding of the inlet and outlet edges of the precision forged blade is completed according to the new grinding trajectory. S4, Vibratory finishing: The precision forged blades after S3 grinding are vibratory finished using a vibratory finishing machine, which turns the small pointed tips of the inlet and outlet edges of the precision forged blades into rounded tips. S3 specifically includes the following steps: S31, Measure the actual allowance of the inlet and outlet edges of the precision forged blade to obtain the spatial orientation and actual shape of the precision forged blade; S32, reference registration, uses the ICP algorithm to spatially register the precision forged blade with the measurement data in S31, obtains the optimal spatial coordinate system of the precision forged blade and adjusts the spatial attitude of the blade; S33, Model Reconstruction: Under the optimal coordinate system obtained in S32, based on the theoretical digital model of the precision forged blade and the measurement data in S31, the adaptive machining model of the inlet and outlet sides of the precision forged blade is reconstructed, and the parameter mapping relationship between the theoretical model and the reconstructed model of the precision forged blade is established. S34, adaptive grinding process, adaptively adjusts the grinding trajectory according to the parameter mapping relationship in S33, and adaptively grinds the inlet and outlet edges of precision forged blades.

2. The method for machining the intake and exhaust edges of precision forged blades according to claim 1, characterized in that: The processing device also includes a transition plate (1) and a base plate (2). The transition plate (1) is connected to the machine tool's rotary shaft. The transition plate (1) includes a disc-shaped base. A support beam extends from the center of the base along the axis of the machine tool's rotary shaft. The base plate (2) is mounted on the support beam. The upper end of the base plate (2) has an mounting plane parallel to the machine tool's rotary shaft. The lower ends of the blade back support block (5), the elastic support block (6), and the clamping support block (7) are fixed on the mounting plane.

3. The method for machining the intake and exhaust edges of precision forged blades according to claim 1, characterized in that: The elastic support block (6) includes a support, with a blind hole at the upper end of the support. A support block is slidably connected in the blind hole. The upper end of the support block forms the upper end of the elastic support block (6). A spring is provided between the lower end of the support block and the bottom of the blind hole. A threaded hole is provided on the side of the support, with a locking screw inside the threaded hole. The end of the locking screw points towards the support block.

4. The method for machining the intake and exhaust edges of precision forged blades according to claim 1, characterized in that: In S1, the thickness of the gasket is such that the precision-forged blade located between the two elastic support blocks (6) only undergoes elastic deformation when pressed.

5. The method for machining the intake and exhaust edges of precision forged blades according to claim 1, characterized in that: In S2, a CNC milling program is used, and the air intake edge is milled first, followed by the air exhaust edge.

6. The method for machining the intake and exhaust edges of a precision-forged blade according to claim 1, characterized in that: In step S31, an optical scanning detection method is used to measure the actual allowance of the precision forged blade. The measurement locations include the allowance at the inlet and outlet edges of the precision forged blade, as well as the allowance within a certain distance from the leading and trailing edges of the precision forged blade.

7. The method for machining the intake and exhaust edges of precision forged blades according to claim 1, characterized in that: In S34, a flexible fiber grinding wheel is used for grinding. The grinding wheel diameter is Φ300mm, the grinding depth is 3mm~5mm, and the grinding deflection angle is ±20°.

8. The method for machining the intake and exhaust edges of a precision forged blade according to claim 1, characterized in that: In step S1, the gasket is a copper sheet with a thickness of 0.03 mm. In S2, the reserved machining allowance is 0.3mm to 0.4mm, the milling tool is D6R3, the milling spindle speed is 2500r / min, and the feed rate is 500mm / min.

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