Nondestructive testing method for minimum curvature radius of micropore abrasive flow machining chamfer
By using image acquisition equipment and mathematical model calculations, non-destructive testing of micro-hole chamfers was achieved, solving the problems of high cost and low accuracy of traditional testing methods and improving testing efficiency and accuracy.
Patent Information
- Application Number
- CN202511413965.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-29
- Publication Date
- 2026-01-09
AI Technical Summary
Existing technologies for micro-hole chamfering detection are costly and their accuracy is affected by human sample preparation errors. Traditional detection methods are difficult to accurately characterize the non-standard arc-shaped orifice inlet morphology formed by abrasive flow processing, resulting in limited guidance for subsequent workpiece fluid dynamics analysis and material fatigue behavior analysis based on the detection results.
The micropore feature parameters are obtained using image acquisition equipment, the minimum radius of curvature of the chamfer is calculated using a mathematical model, and high-resolution images of the micropore opening edge are obtained using a microscope or a fully automated optical imaging measuring instrument. A fitting curve equation is established by combining multiple linear regression or polynomial regression to achieve non-destructive testing.
It reduces the cost of micro-hole chamfering measurement, avoids measurement errors caused by human error in sample preparation, improves detection efficiency, ensures workpiece integrity, and meets the rapid detection needs of industrial production.
Smart Images
Figure CN121297722A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of precision machining technology and relates to a non-destructive testing method for the minimum radius of curvature of chamfers produced by microporous abrasive flow machining. Background Technology
[0002] Micro-channels have significant applications in aerospace precision components, characterized by complex geometries and stringent surface quality requirements (Ra < 0.8 μm, no subsurface damage). Abrasive flow polishing (AFL) has become the preferred post-processing technique due to its unique advantages, particularly suitable for the efficient and precise machining of micro-holes with high aspect ratios (L / D > 8). This technique uses high pressure to force abrasive particles into the micro-hole, utilizing the micro-cutting action of the abrasive to achieve surface polishing, deburring, and shape correction. During AFL machining, the chamfer morphology at the hole inlet not only reduces stress concentration and improves the fatigue performance of the part, but also significantly influences the hydrodynamic behavior of the micro-channel.
[0003] However, existing technologies for detecting chamfers in micro- and nano-scale micropores have many limitations. Traditional detection methods typically require cutting the polished micropores along their central axis for destructive testing. This method is not only costly, but its accuracy is also significantly affected by human error in sample preparation. Furthermore, the inlet shape of the orifice formed by abrasive flow machining is not a standard circular arc, making it difficult for traditional detection methods to accurately characterize its true morphology. Consequently, the detection results have limited guiding significance for subsequent workpiece hydrodynamic analysis and material fatigue behavior analysis. Summary of the Invention
[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a non-destructive testing method for the minimum radius of curvature of chamfers produced by microporous abrasive flow machining, so as to solve the problems of high cost, complicated procedures, and the influence of human sample preparation error on the testing accuracy of microporous chamfers.
[0005] To achieve the above objectives, the present invention employs the following technical solution: A non-destructive testing method for the minimum radius of curvature of a chamfer produced by microporous abrasive flow machining includes the following steps: S1, place the micro-hole in an image acquisition device and acquire the micro-hole feature parameters. The micro-hole feature parameters include the major axis length L at the micro-hole opening, the minor axis length D at L / 4, the longest minor axis length B, and the distance W between the intersection of the longest minor axis and the major axis and the center of the major axis. The major axis is the longest line segment connecting any two points on the edge curve of the micro-hole opening. The minor axis at L / 4 is the line segment connecting two points on the edge curve of the micro-hole opening that is perpendicular to the major axis. The distance between the minor axis at L / 4 and the intersection point is L / 4. The intersection point is the point where the major axis intersects the edge curve. The longest minor axis is the line segment perpendicular to the major axis and is the longest line segment connecting any two points on the edge curve of the micro-hole opening. The edge curve of the micro-hole opening is a closed arc curve. S2, several micropore parameters are input into the mathematical model to obtain the minimum radius of curvature of the chamfer; the mathematical model includes several fitting curve equations, in which the minimum radius of curvature of the chamfer is linearly related to a micropore parameter; several minimum radii of curvature of the chamfer are obtained by fitting curve equations, and the final minimum radius of curvature of the chamfer is obtained based on several minimum radii of curvature of the chamfer.
[0006] A further improvement of the present invention is that: Preferably, in S1, there are two intersection points between the major axis and the edge curve, and correspondingly two minor axes at L / 4. The shortest line segment among them is selected as the minor axis at L / 4.
[0007] Preferably, in S1, the image acquisition device is a microscope or a fully automated optical image measuring instrument.
[0008] Preferably, in S2, the number of fitted curve equations in the mathematical model is equal to the number of micropore feature parameters; if two micropore feature parameters are equal, then the number of fitted curve equations is reduced by one.
[0009] Preferably, the final minimum radius of curvature of the chamfer is obtained by averaging several minimum radius of curvature of the chamfer.
[0010] Preferably, the R-squared of the fitted curve of the mathematical model is... 2 Greater than 0.9.
[0011] Preferably, the fitted curve equation is obtained by calculation using several calibrated micropores, and the micropore characteristic parameters of the calibrated micropores and the measured minimum radius of curvature of the chamfer are all known quantities.
[0012] Preferably, the process of obtaining the fitted curve equation is based on the calibrated micropore characteristic parameters and the measured minimum radius of curvature of the chamfer, and obtains the fitted curve equation through multiple linear regression or polynomial regression.
[0013] Preferably, the measured minimum radius of curvature of the chamfer is obtained by planing the air film hole along the axis and measuring the equivalent circle radius at the chamfer.
[0014] Preferably, the sample has the same slope, the same pore diameter, and the same abrasive flow processing parameters as the calibrated micropore and the micropore with the predicted minimum radius of curvature of the chamfer.
[0015] Compared with the prior art, the present invention has the following beneficial effects: This invention discloses a non-destructive testing method for the minimum radius of curvature of chamfers produced by abrasive flow machining of micro-holes. This method acquires micro-hole feature parameters using an image acquisition device and calculates the radius of curvature based on a mathematical model. Combined with a high-precision fitting equation, non-destructive testing is achieved. The method divides the contour curve of the micro-hole opening into four key measurement parameters; simply measuring these parameters allows the data to be fed into the mathematical model, thus determining the minimum radius of curvature of the micro-hole chamfer. This measurement method significantly reduces the cost of micro-hole chamfering and avoids measurement errors caused by human error in sample preparation, greatly reducing the number of steps required for micro-hole chamfering. It effectively solves the problems of high cost and low efficiency in traditional destructive testing, offering advantages such as reduced testing costs, improved testing efficiency, and guaranteed workpiece integrity. Attached Figure Description
[0016] Figure 1 This is a flowchart of the non-destructive testing method for the minimum radius of curvature of a chamfer processed by microporous abrasive flow according to the present invention; Figure 2 A diagram showing the sampling locations for micropore orifice parameters; Figure 3 This is a flowchart of a specific embodiment of the present invention; Figure 4 Image of the micropore opening in abrasive flow machining of Example 1; Figure 5 Image of the micropore opening in abrasive flow machining, Example 2; Figure 6 Image of the micropore opening in abrasive flow machining, Example 3; Figure 7 The image shows the micropore opening of the abrasive flow machining process in Example 4. Detailed Implementation
[0017] The present invention will now be described in further detail with reference to the accompanying drawings: To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used in the specification and claims are explained and defined in general below. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.
[0018] In this article, unless otherwise specified, “contains,” “includes,” “containing,” “has,” or similar terms cover the meanings of “composed of” and “mainly composed of,” for example, “A contains a” covers the meanings of “A contains a and others” and “A contains only a.”
[0019] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.
[0020] The following examples use instruments and equipment conventional in the art. Experimental methods in the following examples, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. All raw materials used in the following examples are conventional commercially available products with specifications conventional in the art. In this specification and the following examples, unless otherwise specified, "%" refers to weight percentage, "parts" refers to parts by weight, and "ratio" refers to weight proportion.
[0021] In abrasive flow machining, a viscoelastic fluid medium containing abrasive particles flows over the workpiece surface under pressure. The abrasive particles continuously and minutely cut, compress, and rub against the protruding parts and sharp edges of the workpiece surface, thereby achieving uniform material removal. This process characteristic makes it excellent for edge treatment, effectively transforming sharp edges into smooth transition surfaces, i.e., forming chamfers.
[0022] The chamfer profile formed after abrasive flow machining typically presents as a smooth, continuous non-circular curve. The shape of this profile is a comprehensive result of the combined effects of various process parameters (such as fluid pressure, abrasive properties, and machining cycle number). To quantitatively characterize the geometric features of this chamfer profile and assess its ability to reduce stress concentration effects, the concept of an "equivalent circle" is often introduced for approximate description. The radius of this "equivalent circle" effectively describes the smoothness of the circular curve. The radius of the equivalent circle is the circle that is tangent to the actual chamfer profile curve formed after machining at its apex and has the best fit. This radius value is a key geometric parameter for evaluating chamfer quality and performance. Analysis revealed that the key geometric features of the micro-orifice edge curve—the lengths of the major and minor axes and their relative positions—are linearly related to the radius of curvature of the film gas vent chamfer. Film gas vents with the same slope and diameter have similar inlet profiles. Traditional methods for film gas vent chamfering involve destructive testing. However, when batch testing film gas vents, non-destructive testing can be used to obtain the minimum radius of curvature of other micro-channel chamfers. Based on this, see [link to relevant documentation]. Figure 1 and Figure 2 The first aspect of this invention discloses a non-destructive testing method for the minimum radius of curvature of a chamfer processed by microporous abrasive flow, comprising the following steps: S1, place the micropore in an image acquisition device and acquire micropore feature parameters. The micropore feature parameters include the major axis length L at the micropore opening, the minor axis length D at L / 4, the longest minor axis length B, and the distance W between the intersection of the longest minor axis and the major axis and the center of the major axis. The major axis is the longest line segment connecting any two points on the edge curve of the micropore opening. The minor axis at L / 4 is the line segment connecting two points on the edge curve of the micropore opening perpendicular to the major axis. The distance between the minor axis at L / 4 and the intersection point is L / 4. The intersection point is the intersection of the major axis and the edge curve. The longest minor axis is the line segment perpendicular to the major axis and the longest line segment connecting any two points on the edge curve of the micropore opening. The edge curve of the micropore opening is a closed arc curve. S2, several micropore parameters are input into the mathematical model to obtain the radius of curvature; the mathematical model includes several fitting curve equations, in which the minimum radius of curvature of the chamfer is linearly related to a micropore parameter; several minimum radius of curvature of the chamfer are obtained by fitting curve equations, and the final minimum radius of curvature of the chamfer is obtained based on several minimum radius of curvature of the chamfer.
[0023] In this invention, the major axis is defined as the longest line segment between two points on the orifice edge curve, used to determine the main extension direction of the micropore, and its endpoint serves as the reference point for subsequent minor axis measurements. The minor axis at L / 4 refers to the longest line segment perpendicular to the major axis, located one-quarter of the distance from the endpoint of the major axis, reflecting the contraction characteristics of the orifice edge in a local region. The longest minor axis is the maximum span perpendicular to the major axis, characterizing the maximum lateral dimension of the orifice. Distance W refers to the distance from the intersection of the longest minor axis and the major axis to the center of the major axis, used to describe the chamfer asymmetry. The mathematical model contains multiple independent fitting equations, each corresponding to a linear mapping relationship between a characteristic parameter and the radius of curvature. Parallel computation of multiple equations can eliminate errors caused by single parameter anomalies.
[0024] Specifically, after acquiring the closed arc-shaped edge curve, the image acquisition device extracts the coordinates of the major axis and its endpoints through geometric analysis. A perpendicular line is drawn at a point one-quarter the length from the endpoint of the major axis towards the center, and the edge curve is scanned along this perpendicular line to obtain the length of the minor axis at L / 4. The scanning or measurement direction is rotated to be perpendicular to the major axis, and the longest minor axis and its intersection point are determined by traversing the edge curve. These parameters are input into a pre-established mathematical model, and each fitted equation outputs a predicted chamfer radius of curvature. Finally, a comprehensive result is obtained through arithmetic or weighted averaging. This process does not require damaging the workpiece structure; three-dimensional curvature calculation can be completed using only two-dimensional image data. This method utilizes only simple microscopic equipment (such as an optical microscope) to measure four parameters of the micropore opening contour, establishing a mathematical model of geometric parameters and radius of curvature, avoiding sample cutting operations in traditional inspection, and achieving truly non-destructive measurement.
[0025] The specific mathematical model formula is as follows: (1) By using the minimum radius of curvature of the chamfer at three measured points, a curve can be fitted to determine the values of a1-a4 and b1-b4, where a1-a4 are all positive numbers. Based on the model formula, the minimum radius of curvature of the chamfer formed by polishing under the same working conditions for any duration can be fitted using the micropore orifice morphology. The average of the calculated Y1-Y4 values can then be used to predict the minimum radius of curvature of the chamfer.
[0026] It should be understood that in S1, before measurement, the workpiece sample after abrasive flow polishing is cleaned and dried to ensure that no impurities adhere to the micropore inlet. During the imaging process, the focus and light source are adjusted to obtain a clear, high-contrast orthographic projection image of the micropore inlet for subsequent measurement and calculation.
[0027] In some embodiments of the present invention, there are two intersection points between the major axis and the edge curve, corresponding to two minor axes at L / 4. The shortest line segment is selected as the minor axis at L / 4. When the edge curve of the micropore opening has an asymmetrical shape, the lengths of the minor axes at L / 4 positions on both sides of the major axis may be inconsistent. By simultaneously measuring the two minor axes at L / 4 and selecting the smaller value, it is taken as one of the core micropore characteristic parameters.
[0028] In some embodiments of the present invention, the image acquisition device can be a microscope or a fully automated optical image measuring instrument, or other microscopic devices for parameter measurement. A microscope is a precision instrument that magnifies tiny objects using an optical lens system; specifically, it can be a digital microscope or a laser confocal microscope, which acquires high-resolution images of the micro-hole opening edge through optical imaging principles. A fully automated optical image measuring instrument is a device that achieves non-contact dimensional measurement based on computer vision technology; specifically, it can be an image measuring instrument equipped with a high-precision CCD sensor and an autofocus system, which extracts the micro-hole geometric parameters through automatic scanning and image processing algorithms. Using a microscope or a fully automated optical image measuring instrument allows for direct non-contact measurement of intact micro-holes, avoiding human error in sample preparation, while preserving the true contour features formed by abrasive flow polishing at the hole entrance. In this invention, both devices have sub-micron level resolution optical systems. Through the above technical solutions, the present invention achieves non-destructive testing of the chamfer radius of curvature of micro-holes, solving the problem of workpiece scrap caused by cutting inspection. Simultaneously, high-precision optical equipment ensures the accuracy of feature parameter extraction, providing reliable input data for subsequent mathematical models. When using a fully automated optical image measuring instrument, the detection efficiency can be increased to more than ten times that of traditional methods, meeting the rapid detection needs of large batches of micro-hole workpieces in industrial production.
[0029] In some embodiments of the present invention, the number of fitted curve equations and the number of micropore feature parameters in the mathematical model are further defined as equal; if two micropore feature parameters are equal, the corresponding fitted curve equation is reduced by one. It should be understood that for any asymmetric shape, the four micropore feature parameters are all different. Generally, the morphology of micropores is mostly pear-shaped, elliptical, and circular. For elliptical micropores, the W value is 0, which has no computational significance; for circular micropores, not only is W 0, but L and B also have equal values. Micropores with the same orifice diameter and slope have similar morphologies to micropores processed with the same process parameters. Therefore, when there are cases where parameter values are equal, the corresponding two equations are merged into one, thereby eliminating the influence of duplicate parameters on the model accuracy. This method of dynamically adjusting the number of equations ensures that the model covers the independent influence of all feature parameters and avoids the waste of computational resources caused by parameter duplication.
[0030] In some embodiments of the present invention, in step S2, the final chamfer minimum radius of curvature is obtained by averaging several chamfer minimum radii of curvature. For micropores, all four micropore characteristic parameters are linearly related to the radius of curvature; therefore, a chamfer radius of curvature can be obtained through each characteristic parameter. Furthermore, through multi-dimensional parameter cross-validation, result deviations caused by measurement errors of a single characteristic parameter can be avoided.
[0031] In some embodiments of the present invention, the R-squared of the fitted curve by the mathematical model is... 2 Greater than 0.9. R 2 Rfit refers to the goodness-of-fit index, used to measure the degree of agreement between the predicted values of a mathematical model and the actual measured values. Specifically, it is calculated by dividing the sum of squares of regression by the sum of squares of total deviations. This index reflects the mathematical model's ability to interpret actual data; the closer the value is to 1, the higher the model's prediction accuracy. In the micro-hole chamfering detection scenario, Rfit... 2 A setting greater than 0.9 effectively ensures that the deviation between the mathematical model's prediction of the minimum radius of curvature of the chamfer and the actual physical shape is within the acceptable range for engineering applications. Specifically, when establishing the mathematical relationship between the micropore characteristic parameters and the minimum radius of curvature of the chamfer, the R-value of the fitted curve is limited. 2 A value of 0.9 or higher ensures that the linear relationship between each feature parameter and the chamfer radius of curvature is statistically significant. For example, when constructing the fitting equation for the major axis length L and the chamfer radius of curvature, if the calculated R... 2 A value of 0.92 indicates that the equation can explain 92% of the variation in chamfer radius of curvature, with the remaining 8% of the error originating from measurement noise or minor influencing factors. This mathematical model with high goodness of fit effectively eliminates the calculation bias caused by the non-ideal arc shape of the micropore edge curve, making the final average radius of curvature of the chamfer calculated by multiple equations closer to the true value.
[0032] In some embodiments of the present invention, for samples with the same processing parameters, aperture, and slope, the micropores basically have the same shape characteristics. Therefore, it is only necessary to perform destructive experiments on a few of these micropores to obtain calibrated and positioned holes, solve for the corresponding coefficients, and obtain the mathematical model for the batch. Here, the calibrated micropores refer to a sample set whose micropore characteristic parameters and the measured minimum radius of curvature of the chamfer are known. Specifically, micropores randomly selected from the same batch of processed samples can be used as calibration samples, and their true radius of curvature data of the chamfer can be obtained through destructive testing.
[0033] In the actual calculation process, for each micropore, the following formula (2) can be obtained. Since the minimum radius of curvature of the chamfer of each micropore is a constant, Y is equal. Taking W as an example, assuming that a destructive test is performed on M micropores, the relationship between M Y and W can be obtained. Plot the Y and W of the M micropores in the same batch on the graph. Combine with methods suitable for linear relationships such as multiple linear regression or polynomial regression, the linear relationship between Y and W in this batch can be obtained. The same method can be used to obtain the linear relationship between Y and D, Y and L, and Y and B.
[0034] (2) It should be understood that in the above process, the more micropores there are (M), the higher the fitting accuracy. Therefore, M≥2, that is, at least two points should determine a straight line relationship.
[0035] The measured minimum radius of curvature of the chamfer refers to the radius of the smallest equivalent circle of the chamfer region's arc profile, obtained directly by physically cutting the microporous sample. Specifically, this can be achieved using metallographic sectioning combined with optical microscopy. This method involves cutting the sample along the microporous axis to expose the chamfer section, and then measuring the geometric parameters of the minimum radius of curvature after magnified imaging. Destructive testing methods refer to measurement techniques that require destroying the integrity of the sample. In the mathematical modeling stage, real data is obtained by sacrificing a portion of the sample, providing a calibration benchmark for the subsequent non-destructive testing model.
[0036] Through the above technical solution, the present invention can establish a high-precision prediction model by utilizing the correlation of data of calibrated micropores within the same sample without damaging the integrity of the sample. This solves the problem that traditional destructive testing methods require the destruction of multiple samples, resulting in excessive costs. The equipment required for measuring the micropore inlet is simple, the amount of measurement data is small, and prediction deviations caused by inconsistent process conditions when testing across samples are avoided. The prediction accuracy of this model is above 80%.
[0037] Example 1 A high-precision non-destructive testing method for chamfer morphology in microporous abrasive flow machining, see [link to relevant documentation]. Figure 3 It includes the following steps: S1. Polishing a 45° inclined hole, photographing the hole morphology at different polishing times, such as... Figure 4 Figures (a) to (f) are shown in the table.
[0038] The process parameters for abrasive flow polishing are shown in Table 1.
[0039] Table 1. Abrasive flow polishing process parameters for Example 1
[0040] S2. The morphological and dimensional parameters of the micropore inlet were measured and statistically analyzed according to the scale, as shown in Table 2.
[0041] Table 2. Micropore inlet morphology and dimensional parameters and measured chamfer radius of curvature of Example 1
[0042] S3. Input the data in Table 2 above into the following formula to determine the values of parameters a1-a4 and b1-b4.
[0043]
[0044] S4. Substituting a1-a4 and b1-b4 into the mathematical model, we obtain the following mathematical model.
[0045]
[0046] S5. The chamfer profile is scanned using a laser confocal microscope. The simulation results are compared with the scanning results. See Table 3 for the parameters of the micro-hole to be predicted, the corresponding measured and predicted minimum radius of curvature of the chamfer. In this embodiment, Figure (a) shows the morphology of the micro-hole entrance before processing. The corresponding micro-hole was not chamfered, so no corresponding data was measured. The minimum radius of curvature of each predicted chamfer is the average of the values of Y1 and Y4.
[0047] Table 3. Minimum radius of curvature of the chamfer predicted by the model.
[0048] The chamfer profile was scanned using a laser confocal microscope. The simulation results were compared with the scanned results to determine the accuracy of the model's prediction. The model's prediction accuracy was found to be above 80% for the minimum radius of curvature of the 45° tilted air film aperture chamfer.
[0049] Example 2 A high-precision non-destructive testing method for chamfer morphology in microporous abrasive flow machining includes the following steps: S1. Polishing right-angle holes: The morphology of the hole openings at different polishing times was photographed, such as... Figure 5 As shown in Figures (a)-(f) of the document.
[0050] The process parameters for abrasive flow polishing are shown in Table 4 below.
[0051] Table 4. Abrasive flow polishing process parameters for Example 2
[0052] S2. The morphological and dimensional parameters of the micropore inlet were measured and statistically analyzed according to the scale, as shown in Table 5.
[0053] Table 5. Micropore inlet morphology and dimensional parameters and measured chamfer radius of curvature of Example 2
[0054] S3. Input the data in Table 5 above into the following formula to determine the values of parameters a1-a4 and b1-b4.
[0055]
[0056] S4. Substituting a1-a4 and b1-b4 into the model, we obtain the following mathematical model.
[0057]
[0058] S5, such as Figure 5 In (a)-(f), the chamfer profile morphology was scanned using a laser confocal microscope. The simulation results and the scanning results were compared. See Table 6 for the micropore parameters to be predicted, the corresponding measured and predicted minimum curvature radius of the chamfer, where the minimum curvature radius of each predicted chamfer is the average of the Y1 and Y4 values.
[0059] Table 6. Minimum radius of curvature of the chamfer predicted by the model.
[0060] The model's prediction accuracy was assessed. The minimum radius of curvature for the right-angle micropore chamfer was verified, and the model's prediction accuracy exceeded 80%.
[0061] Example 3 A high-precision non-destructive testing method for chamfer morphology in microporous abrasive flow machining includes the following steps: S1. Polishing a 30° inclined hole, photographing the hole morphology at different polishing times, such as... Figure 6 As shown in Figures (a)-(f) of the document.
[0062] The process parameters for abrasive flow polishing are shown in Table 7.
[0063] Table 7 Abrasive flow polishing process parameters for Example 3
[0064] S2. The morphological and dimensional parameters of the micropore inlet are measured and statistically analyzed according to the scale, as shown in Table 8.
[0065] Table 8. Micropore inlet morphology and dimensional parameters and measured chamfer radius of curvature in Example 3
[0066] S3. Input the data in Table 8 above into the following formula to determine the values of parameters a1-a4 and b1-b4.
[0067]
[0068] S4. Substituting a1-a4 and b1-b4 into the model, we obtain the following mathematical model.
[0069]
[0070] S5, such as Figure 6 Figures (a)-(f) show the chamfer profile morphology scanned using a laser confocal microscope. The simulation results are compared with the scan results. Table 9 shows the micropore parameters to be predicted, the corresponding measured and predicted minimum curvature radii of the chamfer, where the minimum curvature radius of each predicted chamfer is the average of the Y1 and Y4 values.
[0071] Table 9. Minimum radius of curvature predicted by the model.
[0072] The parameters were substituted into the mathematical model to calculate the chamfer radius of curvature. The chamfer profile was scanned using a laser confocal microscope, and the simulation results were compared with the scan results to determine the model's prediction accuracy. The model's prediction accuracy was found to be over 80% for the minimum radius of curvature of a microporous chamfer with a 30° tilt angle.
[0073] Example 4 A high-precision non-destructive testing method for chamfer morphology in microporous abrasive flow machining includes the following steps: S1. Polishing the inclined hole with a tilt angle of 60°, and taking pictures of the hole morphology at different polishing times, as shown in Figures (a)-(f) in 7.
[0074] The parameters for abrasive flow polishing process are as follows: Table 10 Abrasive flow polishing process parameters for Example 4
[0075] S2. The morphological and dimensional parameters of the micropore inlet are measured and statistically analyzed according to the scale, as shown in Table 11 below.
[0076] Table 11. Micropore inlet morphology and dimensional parameters and measured chamfer radius of curvature of Example 4
[0077] S3. Input the data from Table 11 above into the following formula to determine the values of parameters a1-a4 and b1-b4.
[0078]
[0079] S4. Substitute the above a1-a4 and b1-b4 into the model, calculate the values of Y1-Y4 and find the average.
[0080]
[0081] S5. As shown in Figures (a)-(f) in 7, the chamfer profile is scanned using a laser confocal microscope. The simulation results are compared with the scanning results. See Table 12 for the micropore parameters to be predicted, the corresponding measured and predicted minimum curvature radii of the chamfer, where the minimum curvature radius of each predicted chamfer is the average of the values of Y1 and Y4.
[0082] Table 12 Minimum radius of curvature predicted by the model
[0083] The parameters were substituted into the mathematical model to calculate the chamfer radius of curvature. The chamfer profile was scanned using a laser confocal microscope, and the simulation results were compared with the scan results to determine the model's prediction accuracy. The model's prediction accuracy for the minimum radius of curvature of a microporous chamfer with a 60° tilt angle was verified to be above 80%.
[0084] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A non-destructive testing method for the minimum radius of curvature of a chamfer produced by microporous abrasive flow machining, characterized in that, Includes the following steps: S1, place the micro-hole in the image acquisition device and acquire the micro-hole feature parameters, which include the major axis length L at the micro-hole opening, the minor axis length D at L / 4, the longest minor axis length B, and the distance W between the intersection of the longest minor axis and the major axis and the center of the major axis; the major axis is the longest line segment connecting any two points on the edge curve of the micro-hole opening; The minor axis at L / 4 is a line segment connecting two points on the edge curve of the micropore opening that is perpendicular to the major axis. The distance between the minor axis at L / 4 and the intersection point is L / 4. The intersection point is the point where the major axis intersects the edge curve. The longest minor axis is a line segment perpendicular to the major axis that is the longest line segment connecting any two points on the edge curve of the micropore opening. The edge curve of the micropore opening is a closed arc curve; S2, several micropore parameters are input into the mathematical model to obtain the minimum radius of curvature of the chamfer; the mathematical model includes several fitting curve equations, in which the minimum radius of curvature of the chamfer is linearly related to a micropore parameter; several minimum radii of curvature of the chamfer are obtained by fitting curve equations, and the final minimum radius of curvature of the chamfer is obtained based on several minimum radii of curvature of the chamfer.
2. The non-destructive testing method for the minimum radius of curvature of a chamfer processed by microporous abrasive flow according to claim 1, characterized in that, In S1, there are two intersection points between the major axis and the edge curve, and correspondingly two minor axes at L / 4. The shortest line segment among them is selected as the minor axis at L / 4.
3. The non-destructive testing method for the minimum radius of curvature of a chamfer processed by microporous abrasive flow according to claim 1, characterized in that, In S1, the image acquisition device is a microscope or a fully automated optical image measuring instrument.
4. The non-destructive testing method for the minimum radius of curvature of a chamfer processed by microporous abrasive flow according to claim 1, characterized in that, In S2, the number of fitted curve equations in the mathematical model is equal to the number of micropore feature parameters; if two micropore feature parameters are equal, the number of fitted curve equations is reduced by one.
5. The non-destructive testing method for the minimum radius of curvature of a microporous chamfer according to claim 1, characterized in that, In S2, the final minimum radius of curvature of the chamfer is obtained by averaging several minimum radius of curvature of the chamfer.
6. The non-destructive testing method for the minimum radius of curvature of a chamfer processed by microporous abrasive flow according to claim 1, characterized in that, The R-value of the fitted curve of the mathematical model 2 Greater than 0.
9.
7. A non-destructive testing method for the minimum radius of curvature of a chamfer processed by microporous abrasive flow according to any one of claims 1-6, characterized in that, The fitted curve equation is obtained by calculation using several calibrated micropores. The micropore characteristic parameters of the calibrated micropores and the measured minimum radius of curvature of the chamfer are all known quantities.
8. The non-destructive testing method for the minimum radius of curvature of a chamfer processed by microporous abrasive flow according to claim 7, characterized in that, The process of obtaining the fitted curve equation is based on the calibrated micropore characteristic parameters and the measured minimum radius of curvature of the chamfer, and obtains the fitted curve equation through multiple linear regression or polynomial regression.
9. The non-destructive testing method for the minimum radius of curvature of a chamfer processed by microporous abrasive flow according to claim 7, characterized in that, The measured minimum radius of curvature of the chamfer is obtained by planing the air film hole along the axis and measuring the equivalent circle radius at the chamfer.
10. The non-destructive testing method for the minimum radius of curvature of a chamfer processed by microporous abrasive flow according to claim 7, characterized in that, The samples are those with the same slope, diameter, and abrasive flow processing parameters as the micropores with the calibrated micropores and the micropores with the minimum radius of curvature to be predicted for the chamfer.