Double-mounting-plate blade weight control method

Abstract

The invention belongs to the technical field of aero-engines and gas turbines, and particularly relates to a double-mounting-plate blade weight control method. Comprising the steps of determining a blade body profile and upper and lower mounting plates as main weight reduction areas; a weight reduction strategy is formulated, and the weight is actively controlled by shifting the theoretical machining model towards the negative difference direction of the tolerance zone; acquiring detection data of the key area in the machining process; and a weight measurement program is compiled, the leaf quality is calculated and predicted in real time through the established mathematical model, and the leaf quality is compared with the theoretical weight to judge qualification. According to the method, the weight control gate can be moved forwards, the machining efficiency and the process reliability are remarkably improved while the 100% weight qualification rate is guaranteed, and the method is suitable for manufacturing the double-mounting-plate type blades with the strict requirement for the weight.

Description

Technical Field

[0001] This invention belongs to the field of aero-engine and gas turbine technology, and specifically relates to a method for controlling the weight of blades with dual mounting plates. Background Technology

[0002] The thrust-to-weight ratio is one of the most critical performance indicators of an aero-engine. To improve the thrust-to-weight ratio, reducing the weight of each component as much as possible while ensuring structural strength has become a core research topic in the field of engine design and manufacturing. As one of the largest and most massive components in the engine, and with a milder operating environment compared to high-temperature components such as the high-pressure compressor and turbine, the fan unit has become a primary target for engine weight reduction design.

[0003] Currently, weight reduction in fan blades primarily relies on the use of advanced lightweight materials, such as titanium alloys and titanium-based composites. However, given a fixed material, the final weight of the blade is mainly determined by its structural volume and manufacturing tolerances. Weight control presents unique challenges for double-mounted-plate blades with complex aerodynamic shapes.

[0004] In existing technologies, weight control for blades with similar structures typically relies on the following two methods, but both have significant drawbacks: Idealized machining based on theoretical models: This involves machining strictly according to the theoretical 3D model in the design drawings. However, in actual manufacturing, any machining process inherently involves dimensional variations. If the weight of the final product is required not to exceed the weight of the theoretical model, it means that all dimensional tolerances, especially the blade profile and mounting plate thickness tolerances, must be extremely tight (e.g., tightened to half the original tolerance zone). This approach severely sacrifices manufacturability, significantly increases machining difficulty and manufacturing costs, resulting in low yield and difficulty in meeting the needs of mass production.

[0005] Final inspection and rework: This involves a final weighing of the blade after all processing steps are completed. If the weight exceeds the tolerance, an attempt is made to reduce the weight by manually polishing the blade surface. This method carries significant risks. Lag: Weight problems are only discovered after all processing is complete, at which point it is too late to correct them, and the entire product may be scrapped.

[0006] High risk: If the amount of polishing is too small, the weight reduction will not be effective; if the amount of polishing is too large or the position is improper, it is very easy to cause the blade profile to exceed the tolerance, which will damage the aerodynamic performance and also lead to the product being unqualified.

[0007] High technical difficulty: In the final state, the blades lack a reliable secondary clamping reference, making the process of local polishing extremely difficult, the operation difficult, and the effect hard to control.

[0008] In summary, existing technologies lack an effective method for predicting, monitoring, and proactively controlling the weight of dual-mount plate blades during manufacturing. The industry urgently needs a method that can ensure the final blade weight meets specifications within existing design tolerances by optimizing manufacturing strategies and process inspections. This is crucial to resolving the core contradiction between the manufacturing difficulties caused by strict tolerances and the quality risks associated with subsequent rework. Summary of the Invention

[0009] To address the problems in the prior art, the present invention provides a method for controlling the weight of blades with dual mounting plates.

[0010] The technical solution of this invention is: This invention discloses a method for controlling the weight of blades with dual mounting plates, comprising the following steps: (1) Determine the main factors affecting the weight of the double mounting plate blade, including the dimensional tolerances of the blade profile and the arc surfaces of the upper and lower mounting plates; (2) Formulate weight reduction strategy: For the blade profile, 1 / 3 of the tolerance zone is used as the theoretical machining model; for the upper and lower mounting plate arc surfaces, 1 / 4 of the thickness tolerance zone is used as the theoretical machining model. (3) Determine the weight measurement data: For the blade profile, select the actual deviation value of each cross-section detection point as the weight measurement data; for the upper and lower mounting plates, select the thickness values ​​of multiple cross-sections evenly distributed along the length direction as the weight measurement data. (4) Formulate a weight calculation method: Based on the weight measurement data, calculate the actual weight of the blade and the actual weight of the upper and lower mounting plates using the formula, and compare them with the theoretical weight of the design. (5) Develop a weight calculation program to automate the weight calculation method, including: The blade is divided into three parts: the upper mounting plate, the lower mounting plate, and the blade profile. Obtain the deviation values ​​of each point and substitute them into the volume calculation formula to calculate the actual volume; Calculate the blade mass based on the material density and actual volume; Compare the blade quality with the theoretical quality and output a pass or fail result; Based on the weight calculation results, the processing procedure was adjusted to ensure that the final weight of the blades met the design requirements.

[0011] Furthermore, in the above-mentioned double mounting plate blade weight control method, when the tolerance zone of the blade profile is -0.15mm to +0.15mm, -0.05mm is used as the theoretical machining model in step (2).

[0012] Furthermore, in the above-mentioned double mounting plate blade weight control method, in step (2), when the thickness tolerance of the upper and lower mounting plates is 0.6mm, 0.15mm is used as the theoretical processing model.

[0013] Furthermore, in the above-mentioned double mounting plate blade weight control method, in step (4), the formula for calculating the actual weight value of the blade body is: actual weight value of the blade body = average value of the deviation values ​​of each cross section point of the blade body × density of titanium alloy material × surface area of ​​the blade body.

[0014] Furthermore, in the above-mentioned double mounting plate blade weight control method, in step (4), the evaluation of the actual weight value of the upper and lower mounting plates is based on the comparison of the average thickness value of 10 points with the thickness value of the design theoretical model.

[0015] Furthermore, in the above-mentioned double mounting plate blade weight control method, in step (4) and step (5), the volume calculation formula is as follows: , Where Δi is the positional deviation value, T u and T l V represents the upper and lower limits of the tolerance. u and V l V represents the maximum and minimum solid volumes. 理 Let n be the theoretical volume and n be the number of measurement points.

[0016] Furthermore, in the above-mentioned double-mounted-plate blade weight control method, in step (4) and step (5), the blade mass calculation formula is as follows: , in, For material density, These are the actual volumes of the upper mounting plate, the blade profile, and the under-plane mounting plate, respectively. like If the blade quality is qualified, Then the quality of the blades is substandard.

[0017] Advantages and beneficial effects of the present invention: 1. This invention, by formulating a weight control strategy and developing a weight calculation program, enables real-time prediction and monitoring of blade weight during processing, overcoming the lag of traditional methods that can only determine weight at the final stage. This allows processing personnel to grasp weight trends before the final process is completed, thereby proactively adjusting process parameters and fundamentally avoiding the risk of scrapping the entire part due to final weight deviations.

[0018] 2. This invention does not require controlling weight through extremely tight dimensional tolerances. Instead, it cleverly achieves weight reduction within the given maximum tolerance zone by optimizing the theoretical machining model (e.g., selecting 1 / 3 or 1 / 4 of the tolerance zone). This significantly reduces machining difficulty, improves tool life and machining stability, and substantially increases the yield rate. Simultaneously, it avoids complex post-processing manual finishing, improving machining efficiency by approximately 15%.

[0019] 3. Specific implementation examples of the present invention show that, for titanium alloy double mounting plate blades with a design requirement of 0.345Kg, the method of the present invention successfully solved the problem of weight deviation, achieving the excellent goal of 100% final weight qualification rate, while bringing about a substantial improvement in processing efficiency, and has extremely high engineering application value and economic benefits. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the double mounting plate blade and the mounting plates at both ends. Detailed Implementation

[0021] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. This embodiment uses a titanium alloy fan blade with double mounting plates of a certain type of aero-engine as an example. The blade is approximately 200mm long and has a theoretical design weight of 0.345Kg. A schematic diagram of the double mounting plate blade and the mounting plates at both ends is shown below. Figure 1 As shown.

[0022] Example This embodiment provides a method for controlling the weight of blades with dual mounting plates, and its specific implementation steps are as follows: Step 1: Identify the main factors and areas affecting weight. According to the weight calculation formula (part mass = part area × part height × material density), given a fixed material, the key factor affecting part weight is the blade area and its tolerance. For a double-mounted-plate blade, the areas with the largest surface area and most sensitive to weight are the blade profile and the curved surfaces of the upper and lower mounting plates. Therefore, these two areas are identified as the main targets for weight reduction control.

[0023] Step 2: Develop weight reduction strategies for key areas The core of this step is to select an optimal "theoretical processing model" within the given tolerance range to control weight from the source.

[0024] Blade profile machining strategy: The design drawings specify that the blade profile tolerance zone is -0.15mm to +0.15mm. For the blade profile, the closer the profile is to the lower tolerance, the lighter the weight. However, due to machining deviations, machining the theoretical profile too close to the lower tolerance poses a risk of exceeding the tolerance. Therefore, one-third of the tolerance zone (i.e., -0.05mm) is selected as the new theoretical machining model.

[0025] Top and bottom mounting plate processing strategies: The design drawings specify a thickness tolerance of ±0.3mm for the mounting plate, meaning a total tolerance zone of 0.6mm. For the arcs of the upper and lower mounting plates, the closer the thickness value is to the lower tolerance value, the lighter the weight. However, due to machining deviations, machining the theoretical surface too close to the lower tolerance poses a risk of exceeding the tolerance. Therefore, a point at 1 / 4 of the thickness tolerance zone (i.e., 0.15mm) is selected as the new theoretical machining model.

[0026] Step 3: Determine the weight measurement data and implement process inspection, using digital inspection methods such as contact coordinate measuring machines and optical measuring machines.

[0027] Blade profile measurement data: Multiple cross-sections of the blade profile were inspected, and the actual deviation of the maximum thickness (MAX THICK) of each cross-section was selected as the weight measurement data, as shown in Table 1: Table 1. Blade profile inspection data Inspection items Upper duty Lower the tolerance Section 1 Section 2 Section 3 Section 4 Section 5 Section 6 Section 7 Section 8 CV CONT'R MIN 0.080 -0.120 0.011 0.006 0.005 0.001 -0.004 0.028 0.028 -0.021 CV CONT'R MAX 0.080 -0.120 0.033 0.029 0.028 0.023 0.022 0.006 0.006 0.004 CC CONT'R MIN 0.080 -0.120 0.002 0.004 0.001 -0.006 -0.004 -0.029 -0.029 -0.018 CC CONT'R MAX 0.080 -0.120 0.025 0.024 0.026 0.021 0.020 0.008 0.008 0.011 CHORD WID 0.200 -0.200 0.025 0.033 0.021 0.015 0.008 0.004 0.004 0.01 MAX THICK 0.160 -0.240 0.058 0.053 0.054 0.044 0.042 0.014 0.014 0.015 Measurement data for upper and lower mounting plates: Five measurement sections were evenly selected along the length of the upper and lower mounting plates. Thickness was measured at one point on both the basin side and the back side of each section, resulting in a total of 10 thickness measurements. See Table 2 for details. Table 2 Measurement values ​​of upper and lower mounting plates

[0028] Step 4: Develop a volume calculation method: Based on the weight measurement data, calculate the actual volume of the blade and the actual volume of the upper and lower mounting plates using formulas; Step 5: Develop a weight calculation program to automate the weight calculation method. Based on the above data, a weight calculation program was developed, and its core logic and calculation formula are as follows: The blade is divided into three parts: the upper mounting plate, the lower mounting plate, and the blade profile. Obtain the deviation values ​​of each point and substitute them into the volume calculation formula to calculate the actual volume; , Where Δi is the positional deviation value, T u and T l V represents the upper and lower limits of the tolerance. u and Vl V represents the maximum and minimum solid volumes. 理 Let n be the theoretical volume and n be the number of measurement points.

[0029] Substitute the above measurement data:

[0030] Calculate the blade mass based on the material density and actual volume; The formula for calculating blade mass is:

[0031] in, For material density, These are the actual volumes of the upper mounting plate, the blade profile, and the under-plane mounting plate, respectively. Compare the blade quality with the theoretical quality and output a pass or fail result; like If the blade quality is qualified, the blade can be transferred to the next process. like If the blade quality is substandard, the operator can follow the program prompts to perform small-scale, precise compensation processing on the out-of-tolerance area, provided there is still processing margin, thereby avoiding final scrapping.

[0032] This embodiment If the blades are of acceptable quality, they can be transferred to the next process.

[0033] This embodiment effectively controls the processing of the titanium alloy double-mounted plate blade by applying this method. In mass production, it avoids batch rework or scrapping caused by final weight discrepancies, achieving the excellent goal of 100% final product weight meeting design requirements, while improving overall processing efficiency by approximately 15%.

Claims

1. A method for controlling the weight of blades with dual mounting plates, characterized in that, Includes the following steps: (1) Determine the main factors affecting the weight of the double mounting plate blade, including the dimensional tolerances of the blade profile and the arc surfaces of the upper and lower mounting plates; (2) Formulate weight reduction strategy: For the blade profile, 1 / 3 of the tolerance zone is used as the theoretical machining model; for the upper and lower mounting plate arc surfaces, 1 / 4 of the thickness tolerance zone is used as the theoretical machining model. (3) Determine the weight measurement data: For the blade profile, select the actual deviation value of each cross-section detection point as the weight measurement data; for the upper and lower mounting plates, select the thickness values ​​of multiple cross-sections evenly distributed along the length direction as the weight measurement data. (4) Formulate a weight calculation method: Based on the weight measurement data, calculate the actual weight of the blade and the actual weight of the upper and lower mounting plates using the formula, and compare them with the theoretical weight of the design. (5) Develop a weight calculation program to automate the weight calculation method, including: The blade is divided into three parts: the upper mounting plate, the lower mounting plate, and the blade profile. Obtain the deviation values ​​of each point and substitute them into the volume calculation formula to calculate the actual volume; Calculate the blade mass based on the material density and actual volume; Compare the blade quality with the theoretical quality and output a pass or fail result; Based on the weight calculation results, the processing procedure was adjusted to ensure that the final weight of the blades met the design requirements.

2. The method for controlling the weight of blades with dual mounting plates according to claim 1, characterized in that, In step (2), when the tolerance zone of the blade profile is -0.15mm to +0.15mm, -0.05mm is used as the theoretical machining model.

3. The method for controlling the weight of blades with dual mounting plates according to claim 1, characterized in that, In step (2), when the thickness tolerance of the upper and lower mounting plates is 0.6mm, 0.15mm is used as the theoretical processing model.

4. The method for controlling the weight of blades with dual mounting plates according to claim 1, characterized in that, In step (4), the formula for calculating the actual weight of the blade is: actual weight of the blade = average value of the deviation values ​​of each cross section point of the blade × density of titanium alloy material × surface area of ​​the blade.

5. The method for controlling the weight of blades with dual mounting plates according to claim 1, characterized in that, In step (4), the actual weight value of the upper and lower mounting plates is evaluated based on the comparison between the average thickness value of 10 points and the thickness value of the design theoretical model.

6. The method for controlling the weight of blades with dual mounting plates according to claim 1, characterized in that, In step (4) and step (5), the volume calculation formula is as follows: ， Where Δi is the positional deviation value, and T u and T l V represents the upper and lower limits of the tolerance. u and V l V represents the maximum and minimum solid volumes. 理 Let n be the theoretical volume and n be the number of measurement points.

7. The method for controlling the weight of blades with dual mounting plates according to claim 1, characterized in that, In step (4) and step (5), the formula for calculating the blade mass is as follows: , in, For material density, These are the actual volumes of the upper mounting plate, the blade profile, and the under-plane mounting plate, respectively; if... If the blade quality is qualified, Then the quality of the blades is substandard.

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