Turning machining method for assembling groove of lower mounting plate of double-mounting-plate blade
By using CNC turning and continuous cutting with grooving inserts, the problem of coaxiality accuracy of the upper and lower mounting plates of large-size double mounting plate blades was solved, achieving a high-efficiency and stable machining process, and improving the manufacturing quality and development cycle of aero-engine fan components.
Patent Information
- Application Number
- CN202511599572.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-04
- Publication Date
- 2026-01-16
AI Technical Summary
Traditional CNC milling processes suffer from insufficient rigidity, machining deformation, and difficulty in controlling coaxiality accuracy when machining the lower mounting plate assembly slot of large-size double mounting plate blades. This is especially true for difficult-to-machine materials such as titanium alloys, where the pass rate is extremely low.
The CNC turning method is adopted, and continuous cutting is performed using grooving inserts. By setting reasonable positioning references and machining coordinate systems, combined with a vertical CNC lathe and precise turning program, the cutting force and deformation are controlled to ensure the coaxiality accuracy of the upper and lower mounting plates. Online measurement and tool compensation technology are used to achieve finishing.
The coaxiality accuracy of the upper and lower mounting plates was controlled within 0.05mm, which improved the processing qualification rate to 100%, reduced the scrap rate, improved processing efficiency and economic benefits, and ensured the long-term dimensional stability of the parts.
Smart Images
Figure CN121339501A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of manufacturing technology of aero-engine and gas turbine fan components, specifically relating to a turning method for the mounting groove of the lower mounting plate of a double mounting plate blade. Background Technology
[0002] The dual-mount plate blades of the Shijiazhuang aero-engine fan unit have upper mounting plate bosses and lower mounting plate assembly slots at both ends for precision assembly with the casing and inner ring, respectively. The quality of this assembly directly affects the aerodynamic performance and operational safety of the engine. Therefore, extremely high precision requirements are placed on the coaxiality between the upper and lower mounting plates, which typically needs to be controlled between Ø0.03mm and Ø0.05mm.
[0003] For double-mounted-plate blades with a relatively short overall length (e.g., less than 150 mm), traditional CNC milling methods can generally meet the coaxiality requirements due to their good overall structural rigidity. However, as the blade size increases (overall length greater than 150 mm), especially when using difficult-to-machine materials such as titanium alloys, the blades exhibit significant characteristics of large size, thin walls, and weak rigidity. On such parts, traditional CNC milling reveals inherent technical limitations: Insufficient rigidity and machining deformation: Milling is an intermittent cutting process, which generates significant cutting forces and vibrations. For blades with long cantilever and weak rigidity, these intermittent cutting forces can easily cause workpiece chatter and tool deflection, leading to elastic deformation during machining and causing deviations between the actual and theoretical positions of the machined assembly slots.
[0004] Stress release leads to loss of precision: The cutting heat and cutting force generated during milling introduce significant residual stress into the workpiece surface. After machining, these internal stresses gradually redistribute and release over time, causing workpiece deformation. This results in the coaxiality of the already machined upper and lower mounting plates exceeding tolerances after a period of time, a phenomenon known as "aging deformation."
[0005] Extremely low pass rate: The combined effect of the above-mentioned "processing deformation" and "stress release deformation" makes the coaxiality of the upper and lower mounting plates extremely low, or even zero, when the lower mounting plate assembly slot is machined by CNC milling for large-size double mounting plate blades. This has become a major technical bottleneck in the product development process.
[0006] Therefore, in the field of aero-engine manufacturing, how to break through the limitations of traditional milling processes and develop a new machining method that can effectively control machining stress and deformation and stably ensure the high coaxiality accuracy of the upper and lower mounting plates of large-size double mounting plate blades has become a key technical problem that urgently needs to be solved. Summary of the Invention
[0007] To address the problems in the prior art, the present invention provides a turning method for the mounting groove of the lower mounting plate of a double mounting plate blade.
[0008] The technical solution of this invention is: This invention discloses a turning method for the mounting groove of the lower mounting plate of a double mounting plate blade, comprising the following steps: a) Determine the positioning reference and blade clamping method for machining the lower mounting plate assembly slot: Install the blades on the machining fixture. Use the outer arc surface B of the upper mounting plate boss as the radial reference, and the air intake edge plane A1 of the upper mounting plate and the air intake edge plane A2 of the lower mounting plate as the axial positioning reference. Place them around the entire circle. If there are gaps between the blades, fill the gaps with a feeler gauge to ensure that the blades are installed on the fixture in a free state without gaps. After the blades are installed, first press the axial pressing surface, but ensure that the machined lower mounting plate assembly slot is exposed, and then press the radial pressing surface. b) Determine the coordinate system for machining the lower mounting plate assembly slot: with the arc surface B of the upper mounting plate boss as the origin in the X direction and the exhaust edge C of the machined lower mounting plate assembly slot as the origin in the Z direction, establish the machining coordinate system; c) Determine the tool holder and tool specifications for the lower mounting plate assembly slot: Select the turning tool holder and insert according to the size of the lower mounting plate assembly slot. Select the standard 25*25 specification tool holder according to the equipment type; select the slot insert type, and the insert width should be less than the width of the assembly slot by 0.2mm; select the bottom R angle of the insert according to the bottom R size of the assembly slot. d) Select a vertical CNC lathe for machining; the machine stroke must be greater than the total height and diameter of the workpiece and tooling. e) Design a turning program to perform roughing and finishing. Roughing allows for a 0.2mm allowance for finishing. Finish to the designed dimensions, and control the coaxiality of the upper mounting plate boss and the lower mounting plate groove to within 0.05mm using the program; f) Online measurement: Use the machine tool's built-in probe to detect the machining dimensions, or use general measuring tools to measure. Calculate whether the dimensions are qualified based on the measurement results. If the machining is not in place, modify the tool compensation value for the finishing tool and run the finishing program again until it is qualified.
[0009] Furthermore, in the above-mentioned turning method for the mounting plate assembly groove of the lower mounting plate of the double mounting plate blade, the cutting tool is a grooving cutting tool, the cutting tool width is less than the width of the assembly groove by at least 0.2 mm, and the radius (R) angle is selected according to the bottom R of the assembly groove. When the bottom R angle is less than 1 mm, the cutting tool R with the same size as the bottom R is directly selected. When the bottom R angle is greater than 1 mm, the cutting tool R is selected as R0.4 or R0.8, and the bottom R dimension is ensured by using a circular arc program.
[0010] Furthermore, in the above-mentioned turning method for the mounting plate assembly groove of the lower mounting plate blade, the outer arc surface B of the mounting plate boss is taken as X0, the exhaust edge C of the machined lower mounting plate assembly groove is taken as Z0, and the tool path is controlled by G code to ensure that the coaxiality accuracy is ≤0.05mm.
[0011] Advantages and beneficial effects of the present invention: 1. This invention fundamentally solves the problem of excessive coaxiality tolerance, achieving a quality breakthrough: By replacing traditional CNC milling with CNC turning, intermittent cutting is transformed into continuous cutting, greatly reducing cutting force and vibration. This method overcomes the defects of poor rigidity and easy deformation during long blade milling from a technological principle perspective, enabling the coaxiality accuracy of the upper mounting plate boss and the lower mounting plate assembly groove to be stably controlled within ≤0.05mm. This increases the first-pass yield of this critical dimension from 0% in the original milling process to 100%, solving the core bottleneck that has long restricted the development of large-size double-mounting-plate blades.
[0012] 2. Significantly Improved Machining Efficiency and Economic Benefits: The turning process is stable, eliminating the need for repeated clamping and adjustment due to rework and correction, thus simplifying the process flow. Practice shows that the method of this invention improves the overall machining efficiency of the blade mounting plate by approximately 30%. Simultaneously, the significantly reduced scrap rate and significantly improved pass rate directly save production costs, resulting in considerable economic benefits.
[0013] 3. Effectively suppresses residual stress and ensures long-term dimensional stability: The cutting heat and cutting force generated by turning are more uniform and controllable, and the residual stress introduced into the workpiece is significantly lower than that of milling. This prevents the machined parts from "aging deformation" caused by the release of internal stress, ensuring the long-term stability and reliability of the mounting plate coaxiality accuracy of the blade before assembly and throughout its entire life cycle.
[0014] 4. By fundamentally solving the problem of processing qualification rate, this invention has powerfully promoted the transformation of large-size double mounting plate blades from "unmanufacturable" to "high-efficiency and high-quality manufacturing", greatly shortened the product development cycle, and provided a solid process guarantee for the rapid development and reliable assembly of aero engines and gas turbines. Attached Figure Description
[0015] Figure 1 Schematic diagram of double mounting plate blades and end references Figure 1 ; Figure 2 Schematic diagram of double mounting plate blades and end references Figure 2 ; Figure 3 This is a schematic diagram showing the dimensions of the lower mounting plate of the double mounting plate blade; Figure 4A schematic diagram of the tool setting point when machining the exhaust edge assembly groove of the lower mounting plate; Figure 5 A schematic diagram of machining the exhaust edge assembly groove of the mounting plate by turning. Detailed Implementation
[0016] The accompanying drawings and embodiments described herein provide a further detailed description of specific implementations of the present invention. The following embodiments are for illustrative purposes only and should not be used to limit the scope of the present invention.
[0017] Example In this embodiment, the dimensions of the lower mounting plate of the double mounting plate blade are as follows: Figure 3 As shown.
[0018] A turning method for the mounting groove of the lower mounting plate of a double mounting plate blade is disclosed. To ensure the coaxiality of the mounting groove and the boss of the upper mounting plate, the machining process routes of the upper and lower mounting plates are rationally arranged. The positioning, clamping method, and machining allowance allocation for the lower mounting plate mounting groove are carefully considered during turning, thereby controlling deformation during the machining process of the lower mounting plate mounting groove and the boss of the upper mounting plate. Specifically, the method includes the following steps: a) Determine the positioning datum for machining the mounting plate assembly slot and the blade clamping method: such as Figure 1 and Figure 2 As shown, the blades are installed on the turning fixture. The outer arc surface B of the upper mounting plate boss is used as the radial reference, and the air intake side plane A1 of the upper mounting plate and the air intake side plane A2 of the lower mounting plate are used as the axial positioning reference. The blades are arranged in a full circle. If there is a gap between the blades, the gap is filled with a feeler gauge to ensure that the blades are installed on the fixture in a free state without gaps. After the blades are installed, the axial pressing surface is pressed first, but the assembly groove of the lower mounting plate must be exposed. Then the radial pressing surface is pressed.
[0019] b) Determine the coordinate system for machining the lower mounting plate assembly slot: with the arc surface B of the upper mounting plate boss as the origin in the X direction and the exhaust edge C of the machined lower mounting plate assembly slot as the origin in the Z direction, establish the machining coordinate system.
[0020] c) Determine the tool holder and cutting tool specifications for the lower mounting plate assembly slot: Select the turning tool holder and inserts based on the dimensions of the lower mounting plate assembly slot. In this embodiment, a certain CNC lathe can only install 25*25 specification tool holders, therefore the lathe tool holder is determined to be a 25*25 specification tool holder;
[0021] When machining the assembly groove, select a grooving insert. The radius (R) of the insert is determined by the radius (R) of the part being machined. When the radius is less than 1mm, generally select an insert with the same radius as the desired radius. When the radius is greater than 1mm, commonly used R0.4 / 0.8 inserts are generally selected, and the radius is ensured by using a circular arc program. In addition to the radius (R), the grooving insert also has a width, which is determined by the width of the groove being machined. The tool width should be 0.2mm less than the width of the assembly groove.
[0022] In this embodiment, a groove with a width of 3.2mm and a bottom radius of 0.7mm is machined. A groove insert with a width of 2.7mm and a bottom radius of 0.7mm is selected.
[0023] d) Select a vertical CNC lathe for machining; the machine stroke must be greater than the total height and diameter of the workpiece and tooling. In this embodiment, the outer diameter of the tooling used for the double mounting plate blade with an outer diameter of 900mm is 1000mm. After the blade is installed on the tooling, the height is 200mm. After the tooling pressure plate presses the blade, the height is 245mm. Therefore, a CNC vertical lathe with an X stroke greater than 1000mm and a Z stroke greater than 300 is selected.
[0024] e) Design the turning program to perform roughing and finishing. Roughing leaves a 0.2mm allowance, finishing is performed to the design dimensions, and the coaxiality of the upper mounting plate boss and the lower mounting plate groove is controlled within 0.05mm by the program.
[0025] In this embodiment, the exhaust edge groove 3.2 of the mounting plate is used as an example. The machining diagram of the exhaust edge assembly groove of the mounting plate is shown below. Figure 4 As shown, the turning procedure and analysis are as follows: Program number: O0001 Program version: A Blade tip to blade, point of contact as Figure 3 As shown; Tool setting position: X0 is the arc (Ø892) on surface B of the fixture; Z0 is the dimension C2, marked on surface 3.2. Part Number: 12345 Machine tool: CNC vertical turning center DST1600 Machining dimensions: 3.2 (+0.03 / -0.03), 4.5 (+0.1 / -0.1), Ø662 (+0.03 / -0.03), coaxiality Ø0.03, R0.8 (0 / -0.2) T0200 (Select Tool) T0202 (Select knife compensation) G57G00 (Coordinate system G57) X-400F300 (Tool moved to X-400 position) Z100F300 (Tool moves to Z100 position) M03S10 (Machine tool spindle forward rotation) G01Z6F100 (Tool moved to Z:6) X-230F100 (Tool moved to X: 892-662=230) Z-4.5F0.5 (Tool moves to Z: -4.5) X-231F0.5 (Tool moves to X: 230 + [3.2 - 2.7] * 2 = 231) Z6F100 (Tool raised to Z:6) X-400F300 (Move to a safe location) Z100F300 M30M05 f) Online measurement: Use the machine tool's built-in probe to detect the machining dimensions, or use general measuring tools to measure. Calculate whether the dimensions are qualified based on the measurement results. If the machining is not in place, modify the tool compensation value for the finishing tool and run the finishing program again until it is qualified.
Claims
1. A turning method of a double mounting plate blade lower mounting plate assembly groove, characterized by, It comprises the following steps: a) Determine the positioning reference of the lower mounting plate assembly groove turning machining and the blade clamping method: install the blades on the turning clamp, take the outer circular arc surface B face of the upper mounting plate boss as the radial reference, take the air inlet edge plane A1 of the upper mounting plate and the air inlet edge plane A2 of the lower mounting plate as the axial positioning reference, place a whole circle, if there is a gap between the blades, fill the gap with a plug gauge to ensure that the blades are installed in a free state on the clamp without gaps; after the blades are installed, first press the axial pressing surface, but ensure that the lower mounting plate assembly groove is exposed for machining, and then press the radial pressing surface; b) Determine the coordinate system of the lower mounting plate assembly groove turning machining: take the outer circular arc surface B face of the upper mounting plate boss as the X direction origin, and take the exhaust edge C face of the machined lower mounting plate assembly groove as the Z direction origin to establish the machining coordinate system; c) Determine the cutter bar and tool specifications of the lower mounting plate assembly groove: select a turning cutter bar and a blade according to the size of the lower mounting plate assembly groove, and select a conventional 25*25 specification for the cutter bar according to the equipment type; The blade type is selected as a groove blade, the blade width should be less than the assembly groove width min0.2mm; the R angle size of the blade bottom is selected according to the R size of the assembly groove bottom; d) Select a vertical numerical control lathe for machining, and the equipment stroke needs to be greater than the total height and diameter of the workpiece and the tooling; e) Design a turning program for rough machining and finish machining, reserve 0.2mm allowance for finish machining from rough machining, finish machining to the designed size, and control the coaxiality of the upper mounting plate boss and the lower mounting plate groove within 0.05mm through the program; f) Online measurement: use the machine tool's own probe to detect the machining size, or use general measuring tools to measure, calculate whether the size is qualified according to the measurement result, if not machined in place, modify the finish machining tool offset value, run the finish machining program again until qualified.
2. The method of claim 1, wherein, In the tool selection, the blade is a groove blade, the blade width is less than the assembly groove width min0.2mm, and the R angle is selected according to the assembly groove bottom R; when the groove bottom R angle is less than 1mm, the blade R is directly selected to be consistent with the size of the groove bottom R; when the groove bottom R angle is greater than 1mm, the blade R is selected as R0.4 or R0.8 blade, and the groove bottom R size is ensured through the circular arc program.
3. The method of claim 1, wherein, In the turning program, take the outer circular arc surface B face of the mounting plate boss as X0, and take the exhaust edge C face of the machined lower mounting plate assembly groove as Z0, and control the tool path through G code to ensure that the coaxiality accuracy is ≤0.05mm.