A method for calculating the chord length removal of blade surface vibration finishing

Abstract

The present invention discloses a method for calculating the amount of chord length removed by vibration finishing of blade profiles. The specific steps of the method for calculating the amount of chord length removed by vibration finishing of blade profiles are as follows: Step 1, take n blades of the same model, where n is specifically 5 to 100, and use a three-coordinate measuring machine to measure the leading edge, trailing edge, and chord length of the blades according to the cross section. The measurement results are not fitted. By analyzing the three-coordinate data of blades of known materials before and after vibration finishing, the detection item with the largest change in the remainder is found, and the corresponding relationship between the data and the leading edge and trailing edge R is used to obtain a relatively accurate calculation formula, which plays a reasonable and accurate role in determining the finishing time when compiling the vibration finishing process. Through the standardization research on TC4 blade vibration finishing, the processing method can be extended to the standardization research and production of other series of titanium alloy and high-temperature alloy blades.

Description

Technical Field

[0001] The invention relates to the field of structural design and application technology for manufacturing aircraft engine blades, and in particular provides a method for calculating the amount of chord length removed from vibration finishing of blade profiles. Background Art

[0002] The manufacturing technology of aircraft engine blades is one of the most complex technologies in the turbine machinery manufacturing industry, and it is also a manufacturing technology that involves a wide range of professional fields in the machinery manufacturing industry. Therefore, the level of blade manufacturing technology reflects the level of engine manufacturing technology to a certain extent.

[0003] Vibration finishing is a process that uses a certain movement mode of abrasive and parts to make the abrasive randomly squeeze, scratch and micro-cut the surface of the parts with a certain force, thereby improving the surface finish of the blade. As a widely used surface optimization method, vibration finishing can be used to remove rust, oil, carbon deposits, eliminate thermal stress oxide layers, improve surface finish, and improve the uneven stress problem of shot peening surface.

[0004] Since vibration finishing can improve the surface finish of workpieces, it is inevitable to remove a small amount of excess, especially for thin-walled blades with inlet and outlet edges R of only 0.1-0.2mm. During the vibration finishing process, the removal of the inlet and outlet edges and chord length will be large, while the tolerance band is very small. When determining the vibration finishing time, it is necessary to improve the surface finish while ensuring that the inlet and outlet edges and chord length dimensions do not exceed the tolerance, which is a vibration finishing process technology problem that needs to be solved urgently.

[0005] People are eager to obtain a method for calculating the chord length removal of blade surface vibration finishing with excellent technical effect. Summary of the invention

[0006] The purpose of the present invention is to provide a method for calculating the chord length removal amount of blade surface vibration finishing with excellent technical effect. The linear regression equation of the least square method is used to perform statistics and calculations on a large number of blade samples to obtain a linear regression equation. The equation can reflect the overall margin change trend of the blade, and at the same time, the vibration finishing time of blades with similar sizes can be calculated through known test results, which can improve the reliability of process parameters, provide a theoretical basis for handling on-site quality problems, improve the overall pass rate of the vibration finishing process of parts, and shorten the delivery cycle.

[0007] The specific steps of the method for calculating the chord length removal amount of the blade profile vibration finishing are as follows:

[0008] Step 1: Take n blades of the same model, where n is 5 to 100. Use a three-coordinate measuring machine to measure the leading edge, trailing edge, and chord length of the blade according to the cross section. The blade section is perpendicular to the Z axis of the absolute coordinate system of the blade and is distributed at a certain distance from the origin of the coordinate system. It is the basis for the design unit to construct the blade shape. During product inspection, the blade is measured in three coordinates according to the cross section. The qualified blade shape is determined by the measurement results of each cross section. If the measurement results are not fitted, the measured values ​​of the chord length of each cross section are defined as x1, x2, x3, x4...x i ; The measured value of the front edge of each section is R 1前缘 , R 2前缘 , R 3前缘 , R 4前缘 ……R i前缘 The measured value of the trailing edge of the cross section is R 1后缘 , R 2后缘 , R 3后缘 , R 4后缘 ……R i后缘 , the number of i is equal to n;

[0009] Step 2, the blade in step 1 is subjected to vibration finishing processing for 30 to 60 minutes using a vibration finishing machine; the vibration frequency of the vibration finishing equipment is set to 30 to 40 Hz, and the equilateral triangle or oblique triangle ceramic abrasives with a side length of 5 / 10 / 15 mm are mixed in a ratio of 1:1:1, that is, the mixing ratio of three abrasives of different sizes is 1:1:1, and a grinding liquid suitable for the blade material is selected, and the grinding liquid and deionized water are mixed in a ratio of 1:100 to 150; the deionized water solvent added with the grinding liquid is injected according to 5% to 15% of the total volume of the abrasive, and the vibration frequency, abrasive ratio, grinding liquid ratio and injection amount remain unchanged, and 30 to 60 minutes are selected as the unit vibration time of vibration finishing processing;

[0010] Step 3: For the blades after vibration finishing, the leading edge, trailing edge and chord length of the blades are measured by a three-dimensional coordinate measuring machine according to the cross section. The measurement results are not fitted. The chord length measurement value is defined as the function y1, y2, y3, y4...y i ;The number of i is equal to n;

[0011] Step 4: The measured values ​​of the chord length and the function in step 1 and step 3 are used to form n discrete points on a two-dimensional plane. Figure 1 Middle dot.

[0012] Step 5: Use the least squares method to calculate the discrete points formed in step 4 and obtain the linear regression equation. The linear regression equation is shown in the attached figure. Figure 2 The dashed straight line in .

[0013]

[0014] The average of the measured values ​​of the chord length of each section before vibration finishing Substituting into the linear equation, the obtained y value is the dimension of the blade after vibration finishing calculated;

[0015] , is the amount of chord length removed from the blade section by vibration finishing per unit vibration time; where x is the value of the chord length before vibration finishing, y is the value of the chord length after vibration finishing, and x i is the chord length value measured in the first three coordinates of vibration finishing, y i It is the chord length value of these samples measured in three coordinates after vibration polishing; the unit vibration time is the time selected from 30 to 60 minutes, and the unit time cannot be changed after selection.

[0016] Step 6: Measure the R of each section in step 1. 前缘 , measured R 后缘 It forms a corresponding relationship with the chord length removal amount; when calculating the removal amount per unit finishing time for blades of the same material, let k = R 前缘 +R 尾缘 , the following rules are used for calculation:

[0017] When minimum R 前缘 +Minimum R 尾缘 ≤k≤maxR 前缘 +Maximum R 尾缘 When R 前缘 +R 尾缘 Select the group closest to k from the measured values ​​of 前缘 +R 后缘 The chord length reduction is k = R 前缘 +R 后缘 The amount of chord length removed;

[0018] When k ≥ maximum R 前缘 +Maximum R 尾缘 When the chord length is removed = (minimum R 前缘 +Measured R 后缘 ) / k*minimum chord length removal;

[0019] When k≤minimumR 前缘 +Minimum R 尾缘 When the chord length is removed = (minimum R 前缘 +Measured R 后缘 )*Maximum chord length removal.

[0020] Preferably, the deionized water solvent added with the grinding liquid is injected into the grinding liquid and a portion of the solvent can be added to the vibration finishing equipment every 15 to 20 minutes.

[0021] Preferably, the deionized water solvent added with the grinding liquid is injected into the grinding liquid and can be continuously added into the vibration finishing device by a water pump.

[0022] The calculation method of the chord length removal amount of the blade profile vibration finishing is to analyze the three-coordinate data of the blade of known material before and after vibration finishing, find out the detection item with the largest change in the remainder, and obtain a relatively accurate calculation formula based on the corresponding relationship between the data and the leading edge and trailing edge R, which plays a reasonable and accurate role in compiling the vibration finishing process to determine the finishing time. Through the standardization research of TC4 blade vibration finishing, this processing method can be extended to the standardization research and production of other series of titanium alloy and high-temperature alloy blades. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments:

[0024] Figure 1 Form n discrete point schematic diagrams on a two-dimensional plane for the measured values ​​of the chord length and the function function in step one and step three;

[0025] Figure 2 This is a schematic diagram after calculation of the discrete points formed in step 4;

[0026] Figure 3 A schematic diagram of n discrete points formed on a two-dimensional plane for the measured values ​​of the chord length and the function in step 1 and step 3 in Example 2;

[0027] Figure 4 This is a schematic diagram of the calculation of the discrete points formed in step 4 of Example 2;

[0028] Figure 5 A schematic diagram of n discrete points formed on a two-dimensional plane for the measured values ​​of the chord length and the function in step 1 and step 3 in Example 3;

[0029] Figure 6 This is a schematic diagram of the calculation of the discrete points formed in step 4 of Example 3; DETAILED DESCRIPTION Example 1

[0030] Step 1: Take n blades of the same model, where n is 5 to 100. Use a three-coordinate measuring machine to measure the leading edge, trailing edge, and chord length of the blade according to the cross section. The blade section is perpendicular to the Z axis of the absolute coordinate system of the blade and is distributed at a certain distance from the origin of the coordinate system. It is the basis for the design unit to construct the blade. During product inspection, the blade is measured in three coordinates according to the cross section, and the blade is judged to be qualified by the measurement results of each cross section. The measurement results are not fitted, and the measured values ​​of the chord length of each cross section are defined as x1, x2, x3, x4...x i ; The measured value of the front edge of each section is R 1前缘 , R 2前缘 , R 3前缘 , R 4前缘 ……Ri前缘 The measured value of the trailing edge of the cross section is R 1后缘 , R 2后缘 , R 3后缘 , R 4后缘 ……R i后缘 , the number of i is equal to n;

[0031] Step 2, the blades in step 1 are subjected to vibration finishing processing for 30 to 60 minutes using a vibration finishing machine; the vibration frequency of the vibration finishing equipment is set to 30 to 40 Hz, and the equilateral triangle or oblique triangle ceramic abrasives with a side length of 5 / 10 / 15 mm are mixed in a ratio of 1:1:1, and a grinding liquid suitable for the blade material is selected, and the grinding liquid and deionized water are mixed in a ratio of 1:100 to 150; the deionized water solvent with the grinding liquid added is injected according to 5% to 15% of the total volume of the abrasive, and the vibration frequency, abrasive ratio, grinding liquid ratio and injection amount remain unchanged, and 30 to 60 minutes are selected as the unit vibration time of the vibration finishing processing;

[0032] Step 3: For the blades after vibration finishing, the leading edge, trailing edge and chord length of the blades are measured by a three-dimensional coordinate measuring machine according to the cross section. The measurement results are not fitted. The chord length measurement value is defined as the function y1, y2, y3, y4...y i ; The number of i is equal to n;

[0033] Step 4: The measured values ​​of the chord length and the function in step 1 and step 3 are used to form n discrete points on a two-dimensional plane. Figure 1 Middle dot.

[0034] Step 5: Use the least squares method to calculate the discrete points formed in step 4 and obtain the linear regression equation. The linear regression equation is shown in the attached figure. Figure 2 The straight line in .

[0035]

[0036] The average of the measured values ​​of the chord length of each section before vibration finishing Substituting into the linear equation, the obtained y value is the dimension of the blade after vibration finishing calculated;

[0037] , is the amount of chord length removed from the blade section by vibration finishing per unit vibration time; where x is the value of the chord length before vibration finishing, y is the value of the chord length after vibration finishing, and x i is the chord length value measured in the first three coordinates of vibration finishing, y i It is the chord length value of these samples measured in three coordinates after vibration polishing; the unit vibration time is the time selected from 30 to 60 minutes, and the unit time cannot be changed after selection.

[0038] Step 6: Measure the R of each section in step 1.前缘 , measured R 后缘 It forms a corresponding relationship with the chord length removal amount; when calculating the removal amount per unit finishing time for blades of the same material, let k = R 前缘 +R 尾缘 , the following rules are used for calculation:

[0039] When minimum R 前缘 +Minimum R 尾缘 ≤k≤maxR 前缘 +Maximum R 尾缘 When R 前缘 +R 尾缘 Select the group closest to k from the measured values ​​of 前缘 +R 后缘 The chord length reduction is k = R 前缘 +R 后缘 The amount of chord length removed;

[0040] When k ≥ maximum R 前缘 +Maximum R 尾缘 When the chord length is removed = (minimum R 前缘 +Measured R 后缘 ) / k*minimum chord length removal;

[0041] When k≤minimumR 前缘 +Minimum R 尾缘 When the chord length is removed = (minimum R 前缘 +Measured R 后缘 )*Maximum chord length removal.

[0042] Preferably, the deionized water solvent added with the grinding liquid is injected into the grinding liquid and a portion of the solvent can be added to the vibration finishing equipment every 15 to 20 minutes.

[0043] Preferably, the deionized water solvent added with the grinding liquid is injected into the grinding liquid and can be continuously added into the vibration finishing device by a water pump. Example 2

[0044] A certain grade titanium alloy arc tooth tenon rotor blade, 50 pieces of the blade were selected, and the chord lengths of 7 sections were measured using three-coordinate measurement before the finishing process. The three-coordinate setting was not suitable. Record and set the chord lengths before finishing as x1, x2, x3, x4...x 50 The blades were vibrated and polished for 1 hour. The three-coordinate measurement was performed on each section of the blades after polishing. The three-coordinate evaluation setting was not suitable. The chord lengths after polishing were recorded and set as y1, y2, y3, y4...y 50 ; (x1, y1), (x2, y2), (x3, y3), (x4, y4)…(x 50 ,y 50 ) forms 50 discrete points in the two-dimensional plane.

[0045] The linear regression equation is calculated using the least squares method, and the linear regression equation is obtained as follows Figure 4 Middle straight line. Example 3

[0046] A titanium alloy single mounting plate blade, 50 pieces of the blade were selected, and the chord length of each section was measured using three-coordinate measurement before the finishing process. The three-coordinate setting was not suitable. Record and set the chord length value before finishing as x1, x2, x3, x4...x 50 The blades were vibrated and polished for 1 hour. The three-coordinate measurement was performed on each section of the blades after polishing. The three-coordinate evaluation setting was not suitable. The chord lengths after polishing were recorded and set as y1, y2, y3, y4...y 50 ; (x1, y1), (x2, y2), (x3, y3), (x4, y4)…(x 50 ,y 50 ) forms 50 discrete points in the two-dimensional plane.

[0047] The linear regression equation is calculated using the least squares method, and the linear regression equation is obtained as follows Figure 6 Middle straight line.

Claims

1. A method for calculating the amount of chord length removed from blade profile vibration finishing, characterized in that: The specific steps of the method for calculating the chord length removal amount of the blade profile vibration finishing are as follows: Step 1: Take n blades of the same model, where n is 5 to 100. Use a three-dimensional coordinate measuring machine to measure the leading edge, trailing edge, and chord length of the blade according to the cross section. The measurement results are not fitted. The measured values ​​of the chord length of each cross section are defined as x1, x2, x3, x4...x i ; The measured value of the front edge of each section is R 1前缘 , R 2前缘 , R 3前缘 , R 4前缘 ……R i前缘 The measured value of the trailing edge of the cross section is R 1后缘 , R 2后缘 , R 3后缘 , R 4后缘 ……R i后缘 , the number of i is equal to n; Step 2: The blades in step 1 are subjected to vibration finishing for 30 to 60 minutes using a vibration finishing machine; the vibration frequency of the vibration finishing equipment is set to 30 to 40 Hz; regular triangular or oblique triangular ceramic abrasives with a side length of 5 / 10 / 15 mm are mixed in a ratio of 1:1:1, the grinding liquid and deionized water are mixed in a ratio of 1:100 to 150, and the deionized water solvent with the grinding liquid is injected in a ratio of 5% to 15% of the total volume of the abrasive, and 30 to 60 minutes is selected as the unit vibration time of the vibration finishing process; Step 3: For the blades after vibration finishing, the leading edge, trailing edge and chord length of the blades are measured by a three-dimensional coordinate measuring machine according to the cross section. The measurement results are not fitted. The chord length measurement value is defined as the function y1, y2, y3, y4...y i , the number of i is equal to n; Step 4, forming n discrete points on a two-dimensional plane using the measured values ​​of the chord length and the function in Step 1 and Step 3; Step 5: Use the least squares method to calculate the discrete points formed in step 4 and obtain a linear regression equation; ； ； ； The average of the measured values ​​of the chord length of each section before vibration finishing Substituting into the linear equation, the y value obtained is the dimension of the blade after vibration finishing calculated; , is the amount of chord length of the blade section removed by vibration finishing per unit vibration time; Step 6: Measure the R of each section in step 1. 前缘 , measured R 后缘 It forms a corresponding relationship with the chord length removal amount; when calculating the removal amount per unit finishing time for blades of the same material, let k = R 前缘 +R 尾缘 , the following rules are used for calculation: When minimum R 前缘 +Minimum R 尾缘 ≤k≤maxR 前缘 +Maximum R 尾缘 When R 前缘 +R 尾缘 Select the group closest to k from the measured values ​​of 前缘 +R 后缘 The chord length reduction is k = R 前缘 +R 后缘 The amount of chord length removed; When k ≥ maximum R 前缘 +Maximum R 尾缘 When the chord length is removed = (minimum R 前缘 +Measured R 后缘 ) / k*minimum chord length removal; When k≤minimumR 前缘 +Minimum R 尾缘 When the chord length is removed = (minimum R 前缘 +Measured R 后缘 )*Maximum chord length removal.

2. The method for calculating the chord length removal amount of blade profile vibration finishing according to claim 1, characterized in that: Inject deionized water solvent added with grinding liquid into the grinding liquid. A portion of it can be added to the vibration finishing equipment every 15 to 20 minutes.

3. The method for calculating the chord length removal amount of blade profile vibration finishing according to claim 1, characterized in that: Deionized water solvent added with the grinding liquid is injected into the grinding liquid and can be continuously added to the vibration finishing equipment by a water pump.

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