Automatic evaluation method and system for non-closed blade profile of precision forged blade

Abstract

The application provides a precision-forged blade non-closed blade profile automatic evaluation method and system, comprising the following steps: extracting theoretical closed blade profile data with a normal vector on a three-dimensional model to obtain measured data of the blade profile; constructing a precision-forged blade non-closed blade profile automatic evaluation network, comprising a blade profile segmentation module, a K-point detection module, a blade profile thickness detection module, a blade profile contour detection module and a blade profile out-of-tolerance detection module; inputting measured data of a blade profile of a precision-forged blade to be evaluated and the theoretical closed blade profile data into the precision-forged blade non-closed blade profile automatic evaluation network to obtain a K-point detection report, a blade profile contour detection report, a blade profile thickness detection report and a blade profile out-of-tolerance detection report. The method constructs a precision-forged blade non-closed blade profile automatic evaluation network, converts the precision-forged blade non-closed blade profile evaluation mode from manual operation to automatic evaluation, and eliminates the result difference caused by personnel operation in blade profile evaluation.

Description

Technical Field

[0001] This invention belongs to the technical field of precision forged blade airfoil size evaluation, specifically to an automatic evaluation method and system for non-enclosed airfoil airfoil of precision forged blades. Background Technology

[0002] Precision-forged blades are non-closed airfoils, and coordinate measuring machine (CMM) inspection requires judging deviations in features such as airfoil profile, thickness, offset, torsion, and dispersion, excluding the leading and trailing edges. The requirements and evaluation standards for precision-forged blade inspection differ across processes such as final forging, correction, thickness grouping, chemical milling, polishing, and final inspection. Furthermore, segmented tolerances exist during inspection; that is, the blade base and blade back at the same cross-section are divided into multiple evaluation areas, each with different tolerances. For example… Figure 1 As shown, taking the leaf spring as an example, the leading and trailing edges are not measured. Within 1mm from the leading and trailing edges to the very edge of the measured data, only the trend is assessed. The measurement sections are divided into three ranges: 1mm to 3mm from the intake edge, 3mm from the intake edge to 3mm from the exhaust edge, and 3mm to 1mm from the exhaust edge. These three ranges have different evaluation tolerance zones, increasing the difficulty of the evaluation.

[0003] Due to the complexity of evaluating the non-closed airfoil profile of precision-forged blades, this airfoil profile has always been evaluated manually. Manual evaluation allows for flexible control of annotation positions, but it is inefficient. The main steps are: output of measured airfoil profile data, output of theoretical closed airfoil profile data, best fit, comparison and annotation of deviations between theoretical and actual data, and judgment of the forging condition (e.g., ...). Figure 2 (As shown). The entire process is manual and time-consuming. The best fit between the theoretical closed leaf shape data and the actual data, as well as the labeling of deviations, are performed visually. The evaluation results are greatly affected by the skill level of the personnel. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides an automatic evaluation method and system for non-enclosed blade profiles of precision forged blades. It constructs an automatic evaluation network for non-enclosed blade profiles of precision forged blades, realizing the transformation of the evaluation method from manual operation to automatic evaluation. The evaluation results are not affected by the skill level of the operator, eliminating the difference in results caused by human operation in blade profile evaluation, and making the detection and evaluation results more accurate and stable.

[0005] To achieve the above objectives, the present invention provides the following technical solution: an automatic evaluation method for non-enclosed blade profiles of precision-forged blades, the specific steps of which are as follows:

[0006] S1 extracts theoretical closed airfoil data with normal vectors from the 3D model and obtains the measured airfoil data.

[0007] S2 constructs an automatic evaluation network for the non-closed airfoil of precision-forged blades, including:

[0008] The blade profile segmentation module is used to obtain the blade profile inspection tolerance of the non-closed blade profile of the precision forged blade based on theoretical closed blade profile data and measured data, and to segment the precision forged blade according to the blade profile inspection tolerance, and to assign corresponding tolerances to the evaluation interval of each segment.

[0009] The K-point detection module is used to calculate the thickness deviation, bending, torsion, and dispersion of K-points in each segment interval;

[0010] The blade thickness detection module is used to obtain the thickness deviation of each segment evaluation interval by fitting theoretical closed blade data and measured data;

[0011] The leaf profile detection module is used to obtain the profile deviation of each segment evaluation interval by fitting theoretical closed leaf profile data and measured data;

[0012] The leaf shape deviation detection module is used to mark the point deviations of the leaf base and leaf back with a fixed number of points, and to calculate the profile deviation of any thickness deviation position within each segment evaluation interval.

[0013] S3 inputs the measured data and theoretical closed airfoil data of the precision forged blade profile to be evaluated into the automatic evaluation network of the non-closed airfoil profile of the precision forged blade, and obtains the K-point detection report, airfoil profile detection report, airfoil thickness detection report and airfoil deviation detection report.

[0014] Furthermore, the theoretical closed airfoil data is set with leading and trailing edge boundary points, K-point files, and section numbers to generate theoretical airfoil data in a fixed format. The fixed format theoretical airfoil file includes the number of test sections, the Z-value of each section, the section number, the leading and trailing edge boundary point number of each section, and the number of points of each section.

[0015] Furthermore, in S2, the blade profile segmentation module is used to acquire the blade profile inspection tolerance data of the non-closed blade profile of the precision forged blade. The non-closed blade profile of the precision forged blade is divided into three cases according to the tolerance segmentation: segmented tolerance, non-segmented tolerance, and a combination of segmented and non-segmented tolerance. If it is a non-segmented tolerance, a uniform tolerance is assigned to the evaluation interval of the precision forged blade. If it is a combination of segmented and non-segmented tolerance or a segmented tolerance, the segmented tolerance position is determined according to the leading and trailing edge boundary point number. The precision forged blade is segmented according to the segmented tolerance position, and a corresponding tolerance is assigned to the evaluation interval of each segment.

[0016] Furthermore, in S2, the K-point detection module calculates the measured deviation between the theoretical coordinates of point K and the measured data based on the theoretical blade profile data specified in the process specification. It then uses the measured deviations of the corresponding K-points at each cross-section (blade head and blade back) to obtain the thickness deviation at point K. Finally, it calculates the bending and torsional deviations based on the formulas for point K, bending, and torsion. Specifically, the calculation of the thickness deviation at point K is as follows:

[0017] TNK N=Loc NK NP +Loc NK NB

[0018] Among them, TNK N For N-section K N Point thickness deviation, Loc NK NP For the K-section blade basin K N Point normal deviation, Loc NK NB For the N-section blade back K N Point normal deviation;

[0019] The bending deviation is the normal deviation of point K in the middle of the leaf basin in the other detection sections besides the leaf root and leaf tip detection sections;

[0020] The torsional deviation refers to the torsion of all test sections except the leaf root test section, and the calculation formula is as follows:

[0021]

[0022] Among them, K1 y -K3 y To detect the distance in the Y direction between points K at both ends of the cross-section blade basin, K1 x -K3 x To detect the distance in the X direction between points K at both ends of the blade basin in the cross section;

[0023] The dispersion is the difference between the maximum and minimum deviations at point K of the detection section, and the calculation formula is:

[0024] K dis =TK max -TK min

[0025] Note: K dis TK represents the dispersion at point K of the leaf shape. max TK represents the maximum thickness deviation at point K. min This represents the minimum thickness deviation at point K.

[0026] Furthermore, in S2, the blade thickness detection module is used to best fit the measured data with the theoretical closed blade data through Y-direction translation and z-direction twisting, and then evaluate the thickness deviation of each evaluation interval relative to the theoretical closed blade data.

[0027] Furthermore, in S2, the best fit is performed using the least squares method. The principle of the best fit is that the sum of the squares of the deviations of the selected fitting benchmark measured data from the theoretical closed blade profile data is minimized. The fitting benchmark is determined according to the inspection requirements in the precision forging blade process.

[0028] Furthermore, in S2, the non-closed blade profile evaluation of the precision-forged blade in the blade profile detection module is an elastic profile evaluation: when the measured trend of the leading and trailing edge region of the blade profile is an opening trend relative to the theoretical value, the measured deviation of the leading and trailing edge of the blade profile is ignored when calculating the blade profile deviation; when the measured trend of the leading and trailing edge region of the blade profile is a contraction trend relative to the theoretical value, the measured deviation of the leading and trailing edge of the blade profile is calculated together with the profiles of other regions of the blade profile when calculating the blade profile deviation.

[0029] Furthermore, in S2, during the evaluation of the blade profile, the measured data are best fitted to the blade profile of each test section using the least squares method by translating in the Y direction and twisting in the Z direction with the theoretical closed blade profile data, and the blade profile deviation is judged; the fitting benchmark is determined according to the inspection requirements in the precision forging blade process; the principle of best fitting is to minimize the sum of squares of the deviations of the measured data of the selected fitting benchmark relative to the theoretical closed blade profile data.

[0030] Furthermore, in S2, the fixed number of points in the blade shape deviation detection module is selected based on the width of the blade shape, and the location of the thickness deviation is displayed on the blade shape deviation detection report through the thickness tolerance. The upper deviation is displayed in red, the lower deviation is displayed in blue, and the maximum and minimum point deviations of each blade shape segment are marked.

[0031] This invention also provides an automatic evaluation system for non-enclosed blade profiles of precision-forged blades, comprising:

[0032] The data acquisition module is used to extract theoretical closed airfoil data with normal vectors from the 3D model and obtain the measured data of the airfoil.

[0033] The evaluation network construction module is used to construct an automatic evaluation network for the non-closed airfoil of precision-forged blades. This automatic evaluation network includes: an airfoil segmentation module, used to obtain the airfoil detection tolerance of the non-closed airfoil of the precision-forged blade based on theoretical closed airfoil data and measured data, and to segment the precision-forged blade according to the airfoil detection tolerance, assigning corresponding tolerances to each segment evaluation interval; a K-point detection module, used to calculate the K-point thickness deviation, bending, torsion, and dispersion of each segment evaluation interval; an airfoil thickness detection module, used to obtain the thickness deviation of each segment evaluation interval by fitting theoretical closed airfoil data and measured data; an airfoil profile detection module, used to obtain the profile deviation of each segment evaluation interval by fitting theoretical closed airfoil data and measured data; and an airfoil deviation detection module, used to mark the point deviations of the blade base and blade back with a fixed number of points, and to calculate the profile deviation at any thickness deviation location within each segment evaluation interval.

[0034] The evaluation result acquisition module is used to input the measured data and theoretical closed air profile data of the precision forged blade to be evaluated into the automatic evaluation network of the non-closed air profile of the precision forged blade, and obtain the K-point detection report, air profile profile detection report, air profile thickness detection report and air profile deviation detection report.

[0035] Compared with the prior art, the present invention has at least the following beneficial effects:

[0036] This invention provides an automatic evaluation method for non-enclosed blade profiles in precision forging. By constructing an automatic evaluation network for non-enclosed blade profiles in precision forging, the evaluation method is transformed from manual operation to automatic evaluation. The evaluation results are not affected by the operator's skill level, eliminating the differences in results caused by human operation in blade profile evaluation, making the detection and evaluation results more accurate and stable. In addition, combined with the detection requirements in the process, a K-point detection report, a blade profile detection report, a blade profile thickness detection report, and a blade profile deviation detection report can be obtained. The detection and evaluation results are reflected in the form of graphical and tabular reports. The tabular report can directly determine whether the part is qualified, and the graphical report can reflect the blade profile dimensional change status. This satisfies both the quality control requirements in the process and the judgment of the final inspection qualification status, making the evaluation results clear and concise. The evaluation method of this invention is more accurate, efficient, and stable than the original evaluation method.

[0037] Furthermore, in the blade profile segmentation mold of the present invention, each part number obtains the blade profile detection tolerance of the non-closed blade profile of the precision forged blade based on theoretical closed blade profile data and measured data, and segments the precision forged blade according to the blade profile detection tolerance, and assigns corresponding tolerances to the evaluation intervals of each segment. The blade profile is classified and evaluated according to different tolerance segmentation situations. When the same part number is evaluated repeatedly, the corresponding type is directly selected for classification and evaluation, resulting in high efficiency of blade profile evaluation.

[0038] Furthermore, the present invention includes a blade profile segmentation module, a K-point detection module, a blade profile thickness detection module, a blade profile contour detection module, and a blade profile deviation detection module. By integrating the detection requirements for non-closed blade profile, K-point, thickness, contour, and deviation of precision-forged blades into one, the evaluation process is templated and standardized, further eliminating the result errors caused by factors such as personnel during the process.

[0039] Furthermore, the automatic evaluation network for non-closed blade profiles of the precision forged blades of this invention can output K-point detection reports, blade profile profile detection reports, blade profile thickness detection reports, and blade profile deviation detection reports. The detection reports are presented in a graphical and tabular format. The tabular reports can directly determine whether the parts are qualified, while the graphical reports can reflect the changes in blade dimensions. This satisfies both the quality control requirements during the process and the judgment of the final inspection qualification status, making the evaluation results clear and concise, and making the evaluation reports more diverse and visual.

[0040] The evaluation method of the present invention can be used as a computer program running on a processor, which can be used in a computer device. In use, multiple testing devices can be controlled by one person. During operation, it is only necessary to clamp the parts and start the computer program to realize the automatic evaluation of the blade profile of precision forged blades. Attached Figure Description

[0041] Figure 1 Schematic diagram of the segmented tolerances of a certain blade;

[0042] Figure 2 Manual evaluation steps for precision-forged blade profiles;

[0043] Figure 3 Schematic diagram of K-point detection report;

[0044] Figure 4 Schematic diagram of blade thickness inspection report;

[0045] Figure 5 Schematic diagram of leaf profile inspection report;

[0046] Figure 6 Schematic diagram of leaf shape out-of-tolerance inspection report. Detailed Implementation

[0047] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0048] This invention provides an automatic evaluation method for parameters such as profile, thickness, bending, and torsion of non-closed blade profiles in precision forging. The specific steps are as follows:

[0049] 1. Extract theoretical blade profile data and process the data to obtain the theoretical blade profile file. Specifically:

[0050] 1.1 According to the drawing inspection requirements, extract the theoretical closed airfoil data with normal vectors from the 3D model. The theoretical closed airfoil data includes the coordinate positions of the points extracted from each inspection section and the surface normal vector, i.e., (x, y, z, i, j, k). Reason for extracting the closed theoretical airfoil data: When evaluating the non-closed airfoil of precision-forged blades, a certain distance from the leading and trailing edges needs to be used as a dividing point to divide the airfoil into multiple segments, thereby realizing multi-segment tolerance evaluation.

[0051] 1.2 Set the leading and trailing edge boundary points, K-point files, and section numbers for the theoretical closed airfoil data to generate a fixed-format theoretical airfoil file; the fixed-format theoretical airfoil file includes the number of test sections, the Z-value of each section, the section number, the leading and trailing edge boundary point numbers of each section, and the number of points in each section;

[0052] 1.3 Obtain measured data of the blade profile and standardize the measured data. The measured data should include the x, y, and z coordinates of the measured points of each test section of the blade profile.

[0053] 2. Establish an automatic evaluation network for the non-closed airfoil profile of precision forged blades. In the automatic evaluation network for the non-closed airfoil profile of precision forged blades, the measured data and theoretical closed airfoil profile data obtained in step 1 are represented in the form of spline curves. Under the original state coordinate system, the characteristic deviations such as thickness, bending, torsion, and dispersion at point K are compared. After the measured data are best fitted with the theoretical closed airfoil profile data through translation in the Y direction and torsion in the Z direction, the contour and thickness deviations of each segment evaluation interval are evaluated relative to the theoretical closed airfoil profile data, and the K-point detection report, airfoil profile detection report, airfoil thickness detection report, and airfoil out-of-tolerance detection report are obtained.

[0054] Specifically, the automatic evaluation network for non-closed blade profiles of precision-forged blades includes a blade profile segmentation module, a K-point detection module, a blade profile thickness detection module, a blade profile contour detection module, and a blade profile deviation detection module.

[0055] In the blade profile segmentation module, based on the blade profile inspection requirements and characteristics for each part number of the precision-forged blade, and according to the Z-value of the cross-section in the theoretical blade profile file with a fixed format, the actual data is calculated by corresponding with the theoretical closed blade profile data. The segmentation tolerance position is determined based on the leading and trailing edge boundary point numbers, thus ensuring the correct setting of the segmentation tolerance. The inspection of non-closed blade profiles of precision-forged blades is divided into three cases according to the tolerance segmentation: segmented tolerance, non-segmented tolerance, and a combination of segmented and non-segmented tolerances. Two automatic blade profile evaluation templates are compiled based on the tolerance segmentation: an evaluation template for blades with non-segmented tolerance zones and an evaluation template for combined segmented and non-segmented tolerance zones. These two evaluation templates determine the evaluation methods corresponding to different tolerance segmentation cases. The calculation methods are the same for different tolerance segmentation cases in the K-point evaluation module, but different in the blade profile evaluation module, blade profile thickness evaluation module, and blade profile out-of-tolerance evaluation module. The comprehensive evaluation template can evaluate blade profiles with segmented tolerances and blade profiles with combined segmented and non-segmented tolerances.

[0056] In the K-point detection module, the theoretical blade profile data extracted in step 1 is compared with the measured data. Based on the theoretical coordinates of the K-point with the normal vector of the theoretical blade profile data for the detection section as specified in the process specification, the corresponding measured deviation is calculated. The K-point thickness deviation is obtained by calculating the measured deviations of the corresponding K-points for each section's blade head and blade back. Furthermore, bending and torsion deviations are calculated using the K-point bending and torsion calculation formulas. This detection module can achieve blade profile size control during the process, specifically including the calculation of K-point thickness deviation, bending, torsion, and dispersion. The specific calculation formulas are as follows:

[0057] 1) K-point thickness deviation: The overall deviation of the blade tip and blade back at fixed points in the inspection section. The calculation formula is:

[0058] TNK N =Loc NK NP +Loc NK NB

[0059] Note: TNK N For N-section K N Point thickness deviation, Loc NK NP For the K-section blade basin K N Point normal deviation, Loc NK NB For the N-section blade back K N Point normal deviation.

[0060] 2) The bending is the normal deviation of point K in the middle of the leaf basin in the detection sections other than the leaf root and leaf tip detection sections.

[0061] 3) For precision-forged blades, the torsion of all test sections except the blade root test section needs to be tested. The calculation formula is:

[0062]

[0063] Note: K1 y -K3 y To detect the distance in the Y direction between points K at both ends of the cross-section blade basin, K1 x -K3 x To detect the distance in the X direction between points K at both ends of the cross-section blade basin.

[0064] 4) Dispersion: The difference between the maximum and minimum deviations at point K. The calculation formula is:

[0065] K dis =TK max -TK min

[0066] Note: K dis TK represents the dispersion at point K of the leaf shape. max TK represents the maximum thickness deviation at point K. min This represents the minimum thickness deviation at point K.

[0067] In the blade thickness detection module, the maximum and minimum thickness deviations of each segment of the entire blade detection section are calculated. Thickness tolerance judgment is added, and the out-of-tolerance situation is displayed in color and a conclusion of whether it is qualified or not is given, making the results clear at a glance.

[0068] In the blade profile detection module, the non-closed blade profile of precision forged blades is detected separately, that is, the blade profile thickness evaluation and the blade profile evaluation are evaluated separately. When evaluating the blade profile, the blade profile of each detection section is best fitted to determine the blade profile deviation, which facilitates the control of blade profile size in the process.

[0069] The evaluation of the non-closed airfoil profile of precision-forged blades is an elastic profile evaluation, which means first determining the opening trend of the airfoil edge, and then determining the calculation range of the profile deviation. When the measured trend of the leading and trailing edge regions of the airfoil is an opening trend relative to the theoretical value, the measured deviation of the leading and trailing edges of the airfoil is not included in the calculation of the airfoil profile deviation; when the measured trend of the leading and trailing edge regions of the airfoil is a contraction trend relative to the theoretical value, the measured deviation of the leading and trailing edges of the airfoil must be calculated together with the profile deviations of other regions of the airfoil. Figure 1 For example, when the leaf edge tends to open, the calculation range of the profile deviation is the area excluding the leading and trailing edges; when the leaf edge tends to contract, the calculation range of the profile deviation is the middle section of the leaf and the leaf edge.

[0070] The blade profile elastic profile evaluation is only used for blade profile evaluation, and not for blade thickness evaluation or blade deviation evaluation reports.

[0071] In the leaf shape deviation detection module, the point deviations of the leaf base and leaf back are marked with a fixed number of points, and the contour deviation of any thickness deviation position in the cross section can be calculated.

[0072] The selection of fixed points is based on the width of the blade shape, and the location of thickness deviation is displayed through the thickness tolerance zone. The upper deviation is displayed in red and the lower deviation is displayed in blue. The maximum and minimum point deviations of each blade shape are also marked to help determine the profile.

[0073] Preferably, when evaluating the blade shape, the least squares method is used for best fitting. The principle of best fitting is to minimize the sum of squares of the deviations of the selected fitting benchmark measured data from the theoretical closed blade shape data.

[0074] The mathematical principle of least squares is: given a set of data (x... i y i (i = 1, 2, ..., n), let its empirical equation be F(x), and the equation contains some undetermined coefficients a. n . (x i y i Substitute into the equation and find the difference y i -F(x) i To account for the overall error, we can take the sum of squares. The reason for squaring is that the positive and negative errors can cancel each other out when added together. Therefore, the error is denoted as:

[0075] e = Σ(y i -F(x) i )) 2

[0076] The principle of best fit: When the precision forged blade profile is best fitted, no translation or rotation is performed in the X direction, only translation is performed in the Y direction, and rotation is performed in the Z direction.

[0077] Selection of fitting reference: Select a suitable fitting reference according to the inspection requirements in the process (in processes such as final forging, correction, and polishing, the blade base is the fitting reference when the fit is optimal; in the final inspection process for blade shape evaluation, the blade base and blade back are the fitting references).

[0078] 3. In use, input the theoretical closed airfoil data and measured data of the precision-forged blade to be evaluated into the automatic evaluation network for the non-closed airfoil of the precision-forged blade. This generates four types of reports: K-point detection report, airfoil profile detection report, airfoil thickness detection report, and airfoil deviation detection report. These four reports include all the evaluation content required for airfoil evaluation in the process. In different processes, according to the testing requirements, the four reports can be combined in any way to obtain an evaluation report that meets the testing needs of that process.

[0079] This invention provides an automatic evaluation system for non-enclosed blade profiles of precision-forged blades, comprising:

[0080] The data acquisition module is used to extract theoretical closed airfoil data with normal vectors from the 3D model and obtain the measured data of the airfoil.

[0081] The evaluation network construction module is used to construct an automatic evaluation network for the non-closed airfoil of precision-forged blades. This automatic evaluation network includes: an airfoil segmentation module, used to obtain the airfoil detection tolerance of the non-closed airfoil of the precision-forged blade based on theoretical closed airfoil data and measured data, and to segment the precision-forged blade according to the airfoil detection tolerance, assigning corresponding tolerances to each segment interval; a K-point detection module, used to calculate the K-point thickness deviation, bending, torsion, and dispersion of each segment interval; an airfoil thickness detection module, used to obtain the thickness deviation of each segment interval by fitting theoretical closed airfoil data and measured data; an airfoil profile detection module, used to obtain the profile deviation of each segment interval by fitting theoretical closed airfoil data and measured data; and an airfoil deviation detection module, used to mark the point deviations of the blade base and blade back with a fixed number of points, and to calculate the profile deviation at any thickness deviation location within each segment interval.

[0082] The evaluation result acquisition module is used to input the measured data and theoretical closed air profile data of the precision forged blade to be evaluated into the automatic evaluation network of the non-closed air profile of the precision forged blade, and obtain the K-point detection report, air profile profile detection report, air profile thickness detection report and air profile deviation detection report.

[0083] Example 1

[0084] This invention provides an automatic evaluation method for the non-enclosed airfoil profile of precision-forged blades, as detailed below:

[0085] Step 1: Design principles of the automatic evaluation program template.

[0086] 1) Customized Automatic Evaluation Templates: Based on the inspection requirements and characteristics of non-enclosed blade profiles for precision-forged blades, non-enclosed blade profiles are categorized into three types: segmented tolerance, non-segmented tolerance, and a combination of segmented and non-segmented tolerances. Two evaluation templates are developed based on the tolerance segmentation: an evaluation template for blades with non-segmented tolerance zones and an evaluation template for combined segmented and non-segmented tolerance zones. The comprehensive evaluation template can evaluate blade profiles with segmented tolerances and blade profiles with combined segmented and non-segmented tolerances.

[0087] When the airfoil inspection tolerance is a non-segmented tolerance, select the non-segmented tolerance evaluation template. After importing parameters such as theoretical closed airfoil data, actual data, leading and trailing edge boundaries, airfoil thickness tolerance zone, airfoil profile tolerance zone, bending, and torsion tolerance zones, generate evaluation modules for each section of the airfoil. In each section evaluation module, set the fitting benchmark according to the inspection requirements in the process, and set the evaluation report output method as needed. Set the output parameter to 1 when a report is required, otherwise set it to 0. In the non-segmented tolerance evaluation template, the airfoil thickness and airfoil profile tolerance zones are single tolerance zones, meaning the tolerance is consistent within the evaluation interval. This evaluation template can only be used to evaluate precision-forged non-closed airfoils where the tolerance requirements for each section of the airfoil are all non-segmented tolerances.

[0088] When the airfoil inspection tolerance is divided into two cases: segmented tolerance and a combination of segmented and non-segmented tolerance, a comprehensive evaluation template is selected. This template allows for the differentiation of the non-segmented evaluation section from the entire airfoil inspection section by setting the non-segmented evaluation section number, thereby setting tolerances within that section for evaluation. For segmented tolerance airfoils, the best-fit method and datum selection method are consistent with those for non-segmented tolerance airfoils. When calculating airfoil profile deviation and thickness deviation, according to the inspection requirements in the process specification, the airfoil's blade base and blade back areas are divided into multiple evaluation intervals, each with a different tolerance zone. This evaluation template can divide the airfoil into multiple evaluation areas by setting multiple airfoil evaluation boundary points, thereby setting different tolerance zones for each area. Airfoils can be evaluated according to tolerance requirements at different locations.

[0089] 2) Determination of the automatic evaluation method for calculating blade dimensions

[0090] According to the requirements for the inspection of precision forged blade profiles, most blade profile evaluations involve segmented tolerances. The principle for achieving segmented tolerances is as follows: extract closed theoretical blade profile data from a 3D model, set leading and trailing edge boundaries, divide the blade profile into multiple segments based on the leading and trailing edge boundaries, and set the tolerances for each segment to achieve segmented tolerance blade profile evaluation.

[0091] Elasticity evaluation: When evaluating the blade profile, adding the judgment of the elastic region can correctly judge the deviation of the blade profile based on the trend of the measured data at the edge.

[0092] Taking leaf pots as an example, the calculation formula is:

[0093] ①When CC EDGES<0, CC EDGES<CC MIN

[0094] CC ALL CONT = CC MAX - CC EDGES

[0095] ②When CC EDGES<0, CC EDGES>CC MIN

[0096] CC ALL CONT = CC MAX - CC MIN

[0097] ③When CC EDGES>0,

[0098] CC ALL CONT = CC MAX - CC MIN

[0099] Note: CC EDGES represents the minimum measured deviation between the outermost edge of the leaf basin and the leading edge. CC ALLCONT represents the overall profile deviation of the leaf basin. CC MAX represents the maximum deviation of the middle section of the leaf basin. CC MIN represents the minimum deviation of the middle section of the leaf basin.

[0100] 3) Design principles for automatic evaluation report content:

[0101] When evaluating the non-enclosed airfoil profile of precision-forged blades, according to the requirements of different processes in the forging process, each process requires a K-point inspection report, an airfoil thickness inspection report, an airfoil profile inspection report, and an airfoil deviation inspection report. To achieve automated evaluation, the algorithm for the reports and the format of each inspection report need to be designed. The specific algorithm and format design are as follows:

[0102] ① The K-point inspection report includes: K-point thickness deviation, bending, torsion, and dispersion. This report is mainly used for blade dimension control during the process and does not evaluate each parameter under optimal fit conditions.

[0103] K-point thickness deviation: The overall deviation of the blade base and blade back at fixed points in the detection section. The calculation formula is:

[0104] TNK N =Loc NK NP +Loc NK NB

[0105] Note: TNK N For N-section K N Point thickness deviation, Loc NK NP For the K-section blade basin K N Point normal deviation, Loc NK NB For the N-section blade back K N Point normal deviation.

[0106] The bending is the normal deviation of point K in the middle of the leaf basin in the detection sections other than the leaf root and leaf tip detection sections.

[0107] For precision-forged blades, the torsion of all test sections except the blade root section needs to be tested. The calculation method differs from the general blade evaluation calculation method. The formula is as follows:

[0108]

[0109] Note: K1 y -K3 y To detect the distance in the Y direction between points K at both ends of the cross-section blade basin, K1 x -K3 x To detect the distance in the X direction between points K at both ends of the cross-section blade basin.

[0110] Dispersion: The difference between the maximum and minimum deviations at point K. The calculation formula is:

[0111] K dis =TK max -TK min

[0112] Note: K dis TK represents the dispersion at point K of the leaf shape. max TK represents the maximum thickness deviation at point K. min This represents the minimum thickness deviation at point K.

[0113] ② Blade thickness inspection report design: Calculate the maximum and minimum thickness deviation of each segment of the entire blade inspection section, add thickness tolerance judgment, display the out-of-tolerance situation in the form of color, and give the conclusion of whether it is qualified or not, so that the results are clear at a glance.

[0114] ③ Blade Profile Inspection Report Design: The non-closed blade profile of precision-forged blades is inspected as a separate item. That is, under the premise of acceptable thickness, the blade profile at each inspection section is optimized for best fit, thereby judging the blade profile deviation. The evaluation of the non-closed blade profile of precision-forged blades is an elastic evaluation, that is, first judging the opening trend of the blade edge, and then determining the calculation range of the profile deviation. Figure 1 For example, when the leaf edge tends to open, the calculation range of the profile deviation is the area excluding the leading and trailing edges; when the leaf edge tends to contract, the calculation range of the profile deviation is the middle section of the leaf and the leaf edge.

[0115] ④ Blade Shape Out-of-Tolerance Inspection Report Design: A fixed number of points are used to mark the deviations of the blade base and blade back. The fixed number of points is selected based on the blade width. The location of thickness deviations is displayed using a thickness tolerance zone; upper deviations are shown in red, and lower deviations in blue. The maximum and minimum point deviations for each blade section are also marked to facilitate profile assessment. This report clearly reflects the blade thickness and profile out-of-tolerance status. During process control, this report can be used to adjust the mold condition, blade polishing range, and optimize blade dimensions.

[0116] Step 2: Construct an automatic evaluation network for the non-closed blade profile of precision-forged blades.

[0117] 1) Extract theoretical airfoil data: Extract closed theoretical airfoil data with normal vectors from the 3D model according to the drawing inspection requirements.

[0118] 2) Generate theoretical files: Use specialized software to process the extracted theoretical airfoil data, set the leading and trailing edge boundary points, K-point files, and section numbers, and generate theoretical airfoil files in a fixed format.

[0119] 3) Standardization of measured data: Standardize the measured data of the blade shape to obtain measured data of the blade shape in a fixed format.

[0120] 4) Construct an automatic evaluation network for the non-closed airfoil of precision-forged blades: Set the evaluation parameter tolerances for each theoretical airfoil data and measured data, select the benchmark, and select the test report to obtain the automatic evaluation network for the non-closed airfoil of precision-forged blades;

[0121] 5) Input the measured data and theoretical closed airfoil data of the precision-forged blade profile to be evaluated into the automatic evaluation network for the non-closed airfoil profile of the precision-forged blade to obtain the K-point detection report, airfoil profile detection report, airfoil thickness detection report, and airfoil deviation detection report, such as... Figures 3-6 As shown.

[0122] When measuring the same part repeatedly, the measured data can be input into the automatic evaluation network for non-closed blade profiles of precision forged blades to generate an inspection report. The whole process takes only about 45 seconds.

Claims

1. An automatic evaluation method for non-closed blade profiles of precision-forged blades, characterized in that, The specific steps are as follows: S1 extracts theoretical closed airfoil data with normal vectors from the 3D model and obtains the measured airfoil data. S2 constructs an automatic evaluation network for the non-closed airfoil of precision-forged blades, including: The blade profile segmentation module is used to obtain the blade profile inspection tolerance of the non-closed blade profile of the precision forged blade based on theoretical closed blade profile data and measured data, and to segment the precision forged blade according to the blade profile inspection tolerance, and to assign corresponding tolerances to the evaluation interval of each segment. The K-point detection module is used to calculate the thickness deviation, bending, torsion, and dispersion of K-points in each segment interval; The blade thickness detection module is used to obtain the thickness deviation of each segment evaluation interval by fitting theoretical closed blade data and measured data; The leaf profile detection module is used to obtain the profile deviation of each segment evaluation interval by fitting theoretical closed leaf profile data and measured data; The leaf shape deviation detection module is used to mark the point deviations of the leaf base and leaf back with a fixed number of points, and to calculate the profile deviation of any thickness deviation position within each segment evaluation interval. S3 inputs the measured data and theoretical closed airfoil data of the precision forged blade profile to be evaluated into the automatic evaluation network of the non-closed airfoil profile of the precision forged blade, and obtains the K-point detection report, airfoil profile detection report, airfoil thickness detection report and airfoil deviation detection report.

2. The automatic evaluation method for non-enclosed blade profiles of precision-forged blades according to claim 1, characterized in that, Set the leading and trailing edge boundary points, K-point files, and section numbers for the theoretical closed airfoil data to generate theoretical airfoil data in a fixed format. The fixed format theoretical airfoil file includes the number of test sections, the Z-value of each section, the section number, the leading and trailing edge boundary point numbers of each section, and the number of points in each section.

3. The automatic evaluation method for non-enclosed blade profiles of precision-forged blades according to claim 2, characterized in that, In S2, the blade profile segmentation module is used to acquire the blade profile inspection tolerance data of the non-closed blade profile of the precision forged blade. The non-closed blade profile of the precision forged blade is divided into three cases according to the tolerance segmentation: segmented tolerance, non-segmented tolerance, and a combination of segmented tolerance and non-segmented tolerance. If it is a non-segmented tolerance, a uniform tolerance is assigned to the evaluation interval of the precision forged blade. If it is a combination of segmented tolerance and non-segmented tolerance or a segmented tolerance, the segmented tolerance position is determined according to the leading and trailing edge boundary point number. The precision forged blade is segmented according to the segmented tolerance position, and a corresponding tolerance is assigned to the evaluation interval of each segment.

4. The automatic evaluation method for non-enclosed blade profiles of precision-forged blades according to claim 1, characterized in that, In S2, the K-point detection module calculates the measured deviation between the theoretical coordinates of point K and the actual measured data based on the theoretical blade profile data specified in the process specification. It then uses the measured deviations of the corresponding K-points at each blade tip and blade back section to obtain the thickness deviation at point K. Finally, it calculates the bending and torsional deviations based on the formulas for point K, bending, and torsion. Specifically, the calculation of the thickness deviation at point K is as follows: TNK N =Loc NK NP +Loc NK NB Among them, TNK N For N-section K N Point thickness deviation, Loc NK NP For the K-section blade basin K N Point normal deviation, Loc NK NB For the N-section blade back K N Point normal deviation; The bending deviation is the normal deviation of point K in the middle of the leaf basin in the other detection sections besides the leaf root and leaf tip detection sections; The torsional deviation refers to the torsion of all test sections except the leaf root test section, and the calculation formula is as follows: Among them, K1 y -K3 y To detect the distance in the Y direction between points K at both ends of the cross-section blade basin, K1 x -K3 x To detect the distance in the X direction between points K at both ends of the cross-section blade basin; The dispersion is the difference between the maximum and minimum deviations at point K of the detection section, and the calculation formula is: K dis =TK max -TK min Note: K dis TK represents the dispersion at point K of the leaf shape. max TK represents the maximum thickness deviation at point K. min This represents the minimum thickness deviation at point K.

5. The automatic evaluation method for non-enclosed blade profiles of precision-forged blades according to claim 1, characterized in that, In S2, the blade thickness detection module is used to best fit the measured data with the theoretical closed blade data through Y-direction translation and z-direction torsion, and then evaluate the thickness deviation of each evaluation interval relative to the theoretical closed blade data.

6. The automatic evaluation method for non-enclosed blade profiles of precision-forged blades according to claim 5, characterized in that, In S2, the best fit is performed using the least squares method. The principle of the best fit is that the sum of the squares of the deviations of the selected fitting benchmark measured data from the theoretical closed blade profile data is minimized. The fitting benchmark is determined according to the inspection requirements in the precision forging blade process.

7. The automatic evaluation method for non-enclosed blade profiles of precision-forged blades according to claim 1, characterized in that, In S2, the non-closed airfoil profile evaluation of precision-forged blades in the airfoil profile detection module is an elastic profile evaluation: when the measured trend of the airfoil's leading and trailing edge regions is an opening trend relative to the theoretical value, the measured deviation of the airfoil's leading and trailing edge regions is ignored when calculating the airfoil profile deviation; when the measured trend of the airfoil's leading and trailing edge regions is a contraction trend relative to the theoretical value, the measured deviation of the airfoil's leading and trailing edge regions is calculated together with the profiles of other areas of the airfoil when calculating the airfoil profile deviation.

8. The automatic evaluation method for non-enclosed blade profiles of precision-forged blades according to claim 7, characterized in that, In S2, during the evaluation of the blade profile, the measured data are best fitted to the blade profile of each test section using the least squares method by translating in the Y direction and twisting in the Z direction with the theoretical closed blade profile data, and the blade profile deviation is judged. The fitting benchmark is determined according to the test requirements in the precision forging blade process. The principle of best fitting is to minimize the sum of squares of the deviations of the measured data of the selected fitting benchmark relative to the theoretical closed blade profile data.

9. The automatic evaluation method for non-enclosed blade profiles of precision-forged blades according to claim 1, characterized in that, In S2, the fixed number of fixed points in the blade shape deviation detection module is selected based on the width of the blade shape. The thickness deviation is displayed on the blade shape deviation detection report through the thickness tolerance. The upper deviation is displayed in red and the lower deviation is displayed in blue. The maximum and minimum point deviations of each blade shape segment are also marked.

10. An automatic evaluation system for non-enclosed blade profiles of precision-forged blades, characterized in that, include: The data acquisition module is used to extract theoretical closed airfoil data with normal vectors from the 3D model and obtain the measured data of the airfoil. The evaluation network construction module is used to construct an automatic evaluation network for the non-closed airfoil of precision-forged blades. This automatic evaluation network includes: an airfoil segmentation module, used to obtain the airfoil detection tolerance of the non-closed airfoil of the precision-forged blade based on theoretical closed airfoil data and measured data, and to segment the precision-forged blade according to the airfoil detection tolerance, assigning corresponding tolerances to each segment evaluation interval; a K-point detection module, used to calculate the K-point thickness deviation, bending, torsion, and dispersion of each segment evaluation interval; an airfoil thickness detection module, used to obtain the thickness deviation of each segment evaluation interval by fitting theoretical closed airfoil data and measured data; an airfoil profile detection module, used to obtain the profile deviation of each segment evaluation interval by fitting theoretical closed airfoil data and measured data; and an airfoil deviation detection module, used to mark the point deviations of the blade base and blade back with a fixed number of points, and to calculate the profile deviation at any thickness deviation location within each segment evaluation interval. The evaluation result acquisition module is used to input the measured data and theoretical closed air profile data of the precision forged blade to be evaluated into the automatic evaluation network of the non-closed air profile of the precision forged blade, and obtain the K-point detection report, air profile profile detection report, air profile thickness detection report and air profile deviation detection report.

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