Optimization Method for Deformable SPR Riveting Dies

Abstract

The present invention discloses an optimization method for deformable SPR riveting dies, which relates to the technical field of riveting dies. The method includes: obtaining the appearance and geometric shape data of the key areas related to riveting of the riveting die in real time through 3D scanning, comparing the appearance and geometric shape data of the riveting die with the design model, and using finite element analysis to diagnose the deformation mode of the riveting die to analyze whether the riveting die needs to be corrected; when the riveting die is corrected, calibrating the riveting die and adjusting the inner cavity depth through an automatic adjustment mechanism, and re-detecting the corrected riveting die to ensure the effectiveness of the correction; comprehensively evaluating the state of the riveting die by combining the initial accuracy of the riveting die and the parting surface adjustment value; comprehensively determining the number of steps for detecting the corrected riveting die by finite element analysis according to the state of the riveting die and the change value of the inner cavity depth amplitude; by optimizing the number of steps for detecting the corrected riveting die by finite element analysis, it is beneficial to improve the detection efficiency of the corrected riveting die.

Description

Technical Field

[0001] The present invention relates to the technical field of riveting dies, and more specifically, to an optimization method for deformable SPR riveting dies. Background Art

[0002] In the existing SPR technology, as a key tool, the accuracy and stability of the riveting die are crucial for the riveting quality. During the use of traditional riveting dies, deviations in shape and size often occur due to factors such as material deformation, processing errors, and wear, which in turn affect the accuracy and quality of riveting. Especially in the riveting process with high-precision requirements, such deviations may lead to problems such as inaccurate pressing force, inaccurate positioning, and uneven pressure distribution, thus affecting the performance and reliability of the final product. To solve the above problems, the commonly used method at present is to regularly detect and correct the riveting die.

[0003] However, after the correction, it is necessary to detect the riveting die again to ensure the effectiveness of the correction. The steps for re-inspecting the corrected riveting die in the traditional method are relatively cumbersome, and the efficiency of detection cannot be ensured. Summary of the Invention

[0004] In order to overcome the above-mentioned defects of the prior art, an embodiment of the present invention provides an optimization method for deformable SPR riveting dies to solve the problems raised in the above background art.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] An optimization method for deformable SPR riveting dies includes the following steps: S1. Real-time obtain the appearance and geometric shape data of the riveting die and the area where riveting is performed through 3D scanning, compare the appearance and geometric shape data of the riveting die with the design model, and use finite element analysis to diagnose the deformation mode of the riveting die to analyze whether to correct the riveting die;

[0007] S2. When the riveting die is corrected, calibrate the riveting die and adjust the inner cavity depth through an automatic adjustment mechanism, and re-detect the corrected riveting die to ensure the effectiveness of the correction;

[0008] S3. Obtain the initial fit clearance deviation and temperature deviation of the riveting die, analyze the initial accuracy of the riveting die according to the fit clearance deviation and temperature deviation, obtain the parting surface adjustment value of the corrected riveting die according to the change in the inner cavity depth of the riveting die, and comprehensively evaluate the state of the riveting die in combination with the initial accuracy of the riveting die and the parting surface adjustment value;

[0009] S4. Collect the change value of the inner cavity depth amplitude of the historical corrected riveting die, and comprehensively evaluate the number of steps for finite element analysis to detect the corrected riveting die according to the state of the riveting die and the change value of the inner cavity depth amplitude.

[0010] In a preferred embodiment, 3D scanning is performed on the appearance and geometry of the riveting die and the area where riveting is carried out to obtain the three-dimensional point cloud data of the riveting die, and the three-dimensional point cloud data of the riveting die is processed. First, noise reduction processing is performed on the three-dimensional point cloud data. Second, registration processing is performed on the three-dimensional point cloud data. Then, optimization of the point cloud density is performed on the three-dimensional point cloud data. Finally, the three-dimensional point cloud data is converted into a 3D model. The data of the design model is obtained through the historical model database, and a deviation map is generated by comparing the processed three-dimensional point cloud data of the riveting die with the design model using 3D comparison software. The data in the deviation map includes shape error data and geometric deviation data. According to the geometry and material properties of the design model, a finite element analysis model of the riveting die is established in 3D software, and the system inputs the data in the deviation map into the finite element analysis model to evaluate the riveting die.

[0011] Specifically, through 3D scanning and finite element analysis, the deformation mode of the riveting die can be accurately diagnosed, thereby guiding the correction process and reducing the blindness and trial-and-error cost of correction.

[0012] In a preferred embodiment, by obtaining the actual gap between the various parts of the riveting die, and obtaining the mating gap between the various components of the design model through the historical model database, the actual gap between the various parts of the riveting die is compared with the mating gap between the various components of the design model to calculate the initial mating gap deviation of the riveting die. The specific calculation formula for the initial mating gap deviation of the riveting die is: ΔG = , where ΔG is the initial mating gap deviation of the riveting die, is the actual gap between the various parts of the riveting die, is the mating gap between the various components of the design model; the actual temperature of the riveting die is obtained through a temperature measuring instrument, the standard temperature of the design model is obtained through the historical model database, and the temperature deviation of the riveting die is calculated based on the actual temperature and the standard temperature. The specific calculation formula is: ΔT = ; where ΔT is the temperature deviation, is the actual temperature of the riveting die, is the standard temperature of the design model; the initial accuracy of the riveting die is analyzed based on the mating gap deviation ΔG and the temperature deviation ΔT, and the final initial accuracy of the riveting die is obtained through normalization and weighted calculation. Among them, the formula for normalizing the mating gap deviation ΔG and the temperature deviation ΔT is: ; is the normalized mating gap deviation, is the allowable tolerance of the mating gap; ; is the normalized temperature deviation, is the temperature allowable tolerance; the initial accuracy of the riveting die is calculated through a weighted formula by combining the mating clearance deviation and the temperature deviation after normalization. The specific formula is: U = + ; where U is the initial accuracy of the riveting die, is the weight coefficient of the normalized mating clearance deviation, is the weight coefficient of the normalized temperature deviation.

[0013] Specifically, by denoising, registering, and optimizing the point cloud density of the three-dimensional point cloud data, the accuracy and integrity of the data can be improved, providing a reliable basis for subsequent analysis and correction.

[0014] In a preferred embodiment, the actual inner cavity depth of the riveting die is obtained through a 3D scanning instrument, and the standard inner cavity depth of the design model is obtained from the historical model database. The change in the inner cavity depth of the riveting die is obtained based on the actual inner cavity depth and the standard inner cavity depth. The specific calculation formula is: ΔD = ; where ΔD is the change in the inner cavity depth of the riveting die, is the actual inner cavity depth of the riveting die, is the standard inner cavity depth of the design model; the parting surface adjustment value of the riveting die after correction is calculated based on the change in the inner cavity depth of the riveting die. The specific calculation formula is ΔZ = ΔD × θ; where ΔZ is the parting surface adjustment value, ΔD is the change in the inner cavity depth of the riveting die, is the parting surface angle; the state of the riveting die is comprehensively evaluated through a weighted formula by combining the initial accuracy of the riveting die and the parting surface adjustment value. The specific formula is: Q = U × + ΔZ × ; where Q is the state of the riveting die, is the weight of the initial accuracy of the riveting die, is the weight of the parting surface adjustment value.

[0015] Specifically, comprehensively evaluating the state of the riveting die by combining the initial accuracy of the riveting die and the parting surface adjustment value can comprehensively reflect the performance and state of the riveting die, guiding the correction process of the riveting die to make it more targeted and effective.

[0016] In a preferred embodiment, the change value of the inner cavity depth amplitude of the historical corrected riveting die is collected, and the number of steps for finite element analysis to detect the corrected riveting die is comprehensively evaluated based on the state of the riveting die and the change value of the inner cavity depth amplitude; according to the data of the historical corrected riveting die, the change in the inner cavity depth of the historical corrected riveting die is averaged as the change value of the inner cavity depth amplitude of the historical corrected riveting die; the number of steps for finite element analysis to detect the corrected riveting die is evaluated through fuzzy inference.

[0017] Technical effects and advantages of the deformable SPR riveting die optimization method of the present invention: By comprehensively evaluating the number of steps for finite element analysis to detect the corrected riveting die based on the state of the riveting die and the change value of the inner cavity depth amplitude, it is beneficial to optimize the number of steps for finite element analysis to detect the corrected riveting die and improve the detection efficiency.

[0018] Through 3D scanning and finite element analysis, the present invention can accurately diagnose the deformation mode of the riveting die, thereby guiding the correction process and reducing the blindness and trial-and-error cost of correction. Description of the Drawings

[0019] Figure 1 It is a schematic structural diagram of the deformable SPR riveting die optimization method of the present invention. Detailed Embodiments

[0020] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0021] In the present invention, SPR is the abbreviation of Self-Piercing Riveting, which is a non-rivet cold connection technology mainly used for connecting lightweight materials (such as aluminum alloys and composite materials). The riveting die needs to bear high dynamic loads in the SPR process, and its deformation directly affects the riveting quality and the die life.

[0022] Embodiment

[0023] The present invention discloses a deformable SPR riveting die optimization method, referring to Figure 1 , including the following steps:

[0024] S1. Obtain the appearance and geometric shape data of the area where the riveting die and the riveting are located in real time through 3D scanning, compare the appearance and geometric shape data of the riveting die with the design model, and use finite element analysis to diagnose the deformation mode of the riveting die to analyze whether to correct the riveting die;

[0025] S2. When the riveting die is corrected, calibrate the riveting die and adjust the inner cavity depth through an automatic adjustment mechanism, and re-detect the corrected riveting die to ensure the correction is effective;

[0026] S3. Obtain the initial fitting clearance deviation and temperature deviation of the riveting die, analyze the initial accuracy of the riveting die according to the fitting clearance deviation and temperature deviation, obtain the parting surface adjustment value of the corrected riveting die according to the change of the inner cavity depth of the riveting die, and comprehensively evaluate the state of the riveting die in combination with the initial accuracy of the riveting die and the parting surface adjustment value;

[0027] S4. Collect the variation value of the inner cavity depth amplitude of the historical corrected riveting die, and comprehensively evaluate the number of steps for detecting the corrected riveting die by finite element analysis according to the die state and the variation value of the inner cavity depth amplitude.

[0028] In this embodiment, S1 includes the following processes:

[0029] Use a 3D scanning instrument to perform 3D scanning on the appearance and geometric shape of the area where the riveting die and the riveting are located, obtain the three-dimensional point cloud data of the riveting die, and process the three-dimensional point cloud data of the riveting die. First, perform denoising processing on the three-dimensional point cloud data, secondly, perform registration processing on the three-dimensional point cloud data, then perform optimized point cloud density processing on the three-dimensional point cloud data, and finally convert the three-dimensional point cloud data into a 3D model.

[0030] Obtain the data of the design model through the historical model database, and use 3D comparison software to compare the processed three-dimensional point cloud data of the riveting die with the design model to generate a deviation map. The data in the deviation map includes shape error data and geometric deviation data.

[0031] It should be explained that the 3D scanning instrument is a device specifically used to obtain data on the appearance and geometric shape of an object, and the historical model database is a database that stores and manages past design models, manufacturing processes, and actual measurement results. The data of the design model in the historical model database is established by design professionals in related fields based on historical data, which will not be elaborated here.

[0032] According to the geometric shape and material properties of the design model, establish a finite element analysis model of the riveting die in 3D software. The system inputs the data in the deviation map into the finite element analysis model to evaluate the riveting die. The specific steps for the finite element analysis model to evaluate the riveting die are as follows: Step 1: Perform stress, heat, and deformation analysis on the riveting die to verify whether the riveting effect of the riveting die meets the expectations; Step 2: Conduct a comprehensive structural analysis on the riveting die to evaluate the overall performance of the riveting die; Step 3: Perform thermo-mechanical coupling analysis on the riveting die to consider the influence of temperature changes on the die strength and deformation; Step 4: Perform simulation evaluations on the long-term behaviors such as fatigue life, wear, and crack propagation of the riveting die to evaluate the service life; Step 5: Perform parameter sensitivity analysis on the riveting die to find out the key factors that may affect the performance; Step 6: According to the analysis results of the steps, evaluate whether the deformation mode of the riveting die can be used normally in the current design. When the deformation mode of the riveting die is lower than the predetermined threshold, the finite element analysis diagnoses that the riveting die needs to be corrected.

[0033] It should be noted that establishing a finite element analysis model of the riveting die in 3D software is a conventional existing technology and will not be elaborated again. For example, the specific steps for establishing the finite element analysis model can be as follows:

[0034] Model foundation construction:

[0035] Geometric model import: Convert the riveting die point cloud data generated by 3D scanning into a solid model (such as STL format) and import it into the finite element analysis software.

[0036] Material property definition: According to the actual material of the riveting die (such as tool steel, cemented carbide, etc.), input basic parameters such as elastic modulus, Poisson's ratio, density, and coefficient of thermal expansion.

[0037] Mesh generation:

[0038] Dense meshes are used in key areas (such as the inner cavity of the riveting die and the parting surface) to ensure the accuracy of stress and deformation analysis;

[0039] Coarser meshes are used in non-critical areas to reduce the computational workload.

[0040] Boundary condition setting:

[0041] Fix the installation surface of the riveting die (constrain displacement and rotational degrees of freedom);

[0042] Apply dynamic loads (pressure, impact force) during the riveting process.

[0043] Thermo-mechanical coupling modeling:

[0044] Heat source definition: According to the riveting process parameters (such as friction coefficient, riveting speed), calculate the frictional heat generation on the contact surface of the riveting die.

[0045] Temperature field analysis: Simulate the temperature distribution of the riveting die during the riveting process and its change over time.

[0046] Thermal stress calculation: Import the temperature field results into the structural analysis module to calculate the additional stress caused by thermal expansion.

[0047] In this embodiment, S2 includes the following processes:

[0048] When the riveting die is corrected, it is calibrated and the inner cavity depth is adjusted through an automatic adjustment mechanism. After the corrected riveting die is re-inspected to ensure the correction is effective;

[0049] During the manufacturing process of the riveting die, deviations or distortions may occur due to material deformation, machining errors, wear, etc. Especially in the riveting process that requires high precision, the accuracy of the shape and size of the riveting die directly affects the quality and precision of riveting. In order to ensure correct pressing force, accurate positioning, and uniform pressure distribution during the riveting process, finite element analysis is used to diagnose the deformation mode of the riveting die to analyze whether the riveting die needs to be corrected. The correction of the riveting die is to restore it to the designed shape and size to ensure its accuracy in subsequent production.

[0050] Specifically, the riveting die evaluation method and judgment criteria are as follows:

[0051] Stress analysis:

[0052] Purpose: To identify the stress concentration areas of the riveting die and prevent material failure.

[0053] Result verification: If the maximum stress is lower than the safety threshold (e.g., 80%) of the material yield strength, it meets the expectation; if it exceeds the threshold, it needs to be corrected.

[0054] Deformation analysis:

[0055] Purpose: To detect the geometric deviations (such as inner cavity depth, parting surface offset) in the key areas of the riveting die.

[0056] Result verification: If the deformation amount is within the design tolerance range, it meets the expectation; if it exceeds the tolerance, it needs to be corrected.

[0057] Thermal analysis:

[0058] Purpose: To evaluate the influence of temperature on the performance of the riveting die (such as thermal softening, thermal fatigue).

[0059] Result verification: If the highest temperature is lower than the thermal stability limit of the material and the temperature gradient is reasonable, it meets the expectation; otherwise, the cooling design needs to be optimized.

[0060] Correction trigger condition: When any one of the stress, deformation, or temperature analysis exceeds the allowable range, it is determined that the riveting die needs to be corrected.

[0061] Example:

[0062] The stress concentration area is close to the material yield limit → The structure needs to be optimized (such as increasing the fillet);

[0063] The inner cavity depth exceeds the tolerance → Adjust the inner cavity size;

[0064] The temperature is too high → Increase the cooling channels or reduce the riveting speed.

[0065] When the riveting die needs to be corrected, the automatic adjustment mechanism uses automated equipment and control systems to precisely adjust the riveting die. Specifically, the actuator corrects the riveting die according to the data in the deviation diagram, adjusting the size, shape, and inner cavity depth of the riveting die; it should be noted that the actuator is a device that can automatically perform physical actions according to input signals or control system instructions.

[0066] The corrected riveting die needs to be re-tested to ensure that the adjustments made are effective and ensure that the riveting die can operate normally in actual work, meeting the riveting accuracy and mechanical requirements.

[0067] In this embodiment, S3 includes the following processes:

[0068] Obtain the initial fitting clearance deviation and temperature deviation of the riveting die, analyze the initial accuracy of the riveting die based on the fitting clearance deviation and temperature deviation, obtain the parting surface adjustment value of the corrected riveting die according to the change in the depth of the inner cavity of the riveting die, and comprehensively evaluate the state of the riveting die by combining the initial accuracy of the riveting die and the parting surface adjustment value;

[0069] Obtain the actual clearance between various parts of the riveting die through a high-precision tool such as a laser rangefinder, obtain the fitting clearance between components of the design model according to the data in the historical model database, compare and calculate the actual clearance between various parts of the riveting die with the fitting clearance between components of the design model to obtain the initial fitting clearance deviation of the riveting die. The specific calculation formula for the initial fitting clearance deviation of the riveting die is: ΔG = , where ΔG is the initial fitting clearance deviation of the riveting die, is the actual clearance between various parts of the riveting die, is the fitting clearance between components of the design model; for example: when the actual clearance between various parts of the riveting die is 0.045 mm and the fitting clearance between components of the design model is 0.05 mm, ΔG = = = 0.005 mm, that is, the initial fitting clearance deviation of the riveting die is 0.005 mm.

[0070] Obtain the actual temperature of the riveting die through a temperature measuring instrument, obtain the standard temperature of the design model according to the historical model database, and calculate the temperature deviation of the riveting die based on the actual temperature and the standard temperature. The specific calculation formula is: ΔT = ; where ΔT is the temperature deviation, is the actual temperature of the riveting die, is the standard temperature of the design model; assume that the standard temperature of the design model = 25 °C and the actual temperature of the riveting die = 30 °C, then ΔT = = 5 °C, and the temperature deviation of the riveting die is 5 °C; analyze the initial accuracy of the riveting die based on the fitting clearance deviation ΔG and the temperature deviation ΔT, and obtain the final initial accuracy of the riveting die through normalization and weighted calculation. Among them, the formula for normalizing the fitting clearance deviation ΔG and the temperature deviation ΔT is: ; is the normalized fitting clearance deviation, is the allowable tolerance of the fitting clearance; ; is the normalized temperature deviation, is the allowable tolerance of the temperature; combine the normalized fitting clearance deviation and the temperature deviation to calculate the initial accuracy of the riveting die through a weighted formula. The specific formula is: U = + ; where U is the initial accuracy of the riveting die, is the weight coefficient of the mating clearance deviation after normalization, is the weight coefficient of the temperature deviation after normalization; assume that the mating clearance deviation ΔG = 0.005 mm, the temperature deviation ΔT = 5 °C, the allowable tolerance of the mating clearance = 0.01 mm, the allowable tolerance of the temperature = 2 °C, the weight coefficient of the mating clearance deviation after normalization = 0.6, the weight coefficient of the temperature deviation after normalization = 0.4; = = 0.5; = 2.5; U = + = 0.6×0.5 + 0.4×2.5 = 1.3. Then, the initial accuracy of the riveting die is 1.3 at this time; a smaller value of the initial accuracy of the riveting die means a higher accuracy of the riveting die, and a larger value of the initial accuracy of the riveting die indicates a larger error and a lower accuracy of the riveting die.

[0071] Obtain the actual inner cavity depth of the riveting die through a 3D scanning instrument, obtain the standard inner cavity depth of the design model through the historical model database, and obtain the change in the inner cavity depth of the riveting die based on the actual inner cavity depth and the standard inner cavity depth. The specific calculation formula is: ΔD = ; where, ΔD is the change in the inner cavity depth of the riveting die, is the actual inner cavity depth of the riveting die, is the standard inner cavity depth of the design model; calculate the parting surface adjustment value of the riveting die after correction based on the change in the inner cavity depth of the riveting die. The specific calculation formula is ΔZ = ΔD×θ; where, ΔZ is the parting surface adjustment value, ΔD is the change in the inner cavity depth of the riveting die, is the parting surface angle.

[0072] Comprehensively evaluate the state of the riveting die by combining the initial accuracy of the riveting die and the parting surface adjustment value through a weighted formula. The specific formula is: Q = U× + ΔZ× ; where, Q is the state of the riveting die, is the weight of the initial accuracy of the riveting die, is the weight of the parting surface adjustment value; assume that ΔD = 0.5 mm, θ = 2 °, the actual inner cavity depth is 10.05 mm, the standard inner cavity depth is 10 mm, = 0.7, = 0.3, then ΔD = = 10.05 mm−10 mm = 0.05 mm, ΔZ = ΔD×θ = 0.05 mm×2 ° = 0.1 mm, Q = U× + ΔZ× = 0.7×1.3 + 0.3×0.1 = 0.91 + 0.03 = 0.94; The smaller the value of the riveting die state, the more ideal the riveting die state is. A larger value of the riveting die state indicates a poorer riveting die state.

[0073] In this embodiment, S4 includes the following processes:

[0074] Collect the change value of the inner cavity depth amplitude of the historical corrected riveting die, and comprehensively evaluate the number of steps for finite element analysis to detect the corrected riveting die according to the riveting die state and the change value of the inner cavity depth amplitude.

[0075] According to the data of the historical corrected riveting die, average the change in the inner cavity depth of the historical corrected riveting die as the change value of the inner cavity depth amplitude of the historical corrected riveting die.

[0076] The specific working process of evaluating the number of steps for finite element analysis to detect the corrected riveting die is as follows:

[0077] Step 1, Define the riveting die state and the change value of the inner cavity depth amplitude as input variables, and divide them into different fuzzy sets respectively.

[0078] For example, "Low", "Medium", "High" for the riveting die state, and "Small", "Medium", "Large" for the change value of the inner cavity depth amplitude;

[0079] Step 2, Define the number of steps for finite element analysis to detect the corrected riveting die as the output variable, and divide it into a fuzzy set. For example, "Few" and "Many" for the number of steps for finite element analysis to detect the corrected riveting die.

[0080] Step 3, Formulate a set of fuzzy rules to describe the influence of different input variables on the output variable. The definition of the rules can be based on professional knowledge or obtained through data analysis and experiments. For example:

[0081] Mark the riveting die state as X, the change value of the inner cavity depth amplitude as V, and the number of steps for finite element analysis to detect the corrected riveting die as J, then it can be defined as

[0082] Rule 1: IF (X is High) AND (V is Large) THEN (J is Many)

[0083] Rule 2: IF (X is Low) AND (V is Small) THEN (J is Few) ...

[0084] Step 4: Perform fuzzy inference according to the fuzzy rules to determine the division scheme of the number of steps for the finite element analysis to detect the corrected riveting die.

[0085] It should be noted that the division of the fuzzy set can be adjusted according to the actual situation. For example, although three fuzzy sets are taken as an example in this embodiment, in fact, the riveting die state, the change value of the inner cavity depth amplitude, and the number of steps for the finite element analysis to detect the corrected riveting die can be divided into more than three sets to facilitate better division of the number of steps for the finite element analysis to detect the corrected riveting die.

[0086] Furthermore, for the judgment of high, medium, and low of the riveting die state and the change value of the inner cavity depth amplitude, thresholds can be set according to the actual situation for judgment. For example, when the riveting die state does not exceed 1.5, it is calibrated as "Low", and when the change value of the inner cavity depth amplitude is not higher than 0.2, it is calibrated as "Small", etc., which will not be elaborated here.

[0087] Among them, when the output variable is "Few", the number of steps for the finite element analysis to detect the corrected riveting die is a large number, and when the output variable is "Many", the number of steps for the finite element analysis to detect the corrected riveting die is a small number.

[0088] In summary, comprehensively evaluating the number of steps for the finite element analysis to detect the corrected riveting die according to the riveting die state and the change value of the inner cavity depth amplitude is beneficial to optimizing the number of steps for the finite element analysis to detect the corrected riveting die and improving the detection efficiency.

[0089] The above formulas are all dimensionless and take their numerical calculations. The formula is obtained by collecting a large amount of data for software simulation to get a formula closest to the real situation. The preset parameters in the formula are set by those skilled in the art according to the actual situation.

[0090] The above embodiments can be implemented in whole or in part by software, hardware, firmware, or any other combination. When implemented using software, the above embodiments can be implemented in whole or in part in the form of a computer program product.

[0091] Those of ordinary skill in the art can realize that the modules and algorithm steps of each example described in combination with the embodiments disclosed herein can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are executed in a hardware or software manner depends on the specific application and the inventive constraints of the technical solution. Those skilled in the art can use different methods for each specific application to implement the described functions, but such implementation should not be considered to exceed the scope of this application.

[0092] In addition, in each embodiment of the present application, each functional module may be integrated into one processing module, may exist separately as individual physical modules, or two or more modules may be integrated into one module.

[0093] As described above, only the specific embodiments of the present application are provided, but the protection scope of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed in the present application can easily think of changes or substitutions, which should all be covered by the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

[0094] Finally: The above are only the preferred embodiments of the present invention and are not used to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims

1. A deformable SPR riveting die optimization method, characterized in that; The steps include: S1. Obtain the appearance and geometric shape data of the riveting die and the riveted area in real time through 3D scanning, compare the appearance and geometric shape data of the riveting die with the design model, and use finite element analysis to diagnose the deformation mode of the riveting die to analyze whether the riveting die should be corrected; S2. When the riveting die is corrected, the riveting die is calibrated and the inner cavity depth is adjusted through the automatic adjustment mechanism, and the corrected riveting die is re-tested to ensure that the correction is effective; S3, obtaining the initial fit clearance deviation and temperature deviation of the riveting mold, analyzing the initial accuracy of the riveting mold according to the fit clearance deviation and the temperature deviation, obtaining the parting surface adjustment value of the corrected riveting mold according to the change of the inner cavity depth of the riveting mold, and comprehensively evaluating the riveting mold state in combination with the initial accuracy of the riveting mold and the parting surface adjustment value; S4, collecting the inner cavity depth amplitude change values ​​of the historically corrected riveting dies, and comprehensively evaluating the number of steps of the finite element analysis to detect the corrected riveting dies according to the riveting die state and the inner cavity depth amplitude change values; By obtaining the actual gap between the parts of the riveting die, the matching gap between the parts of the design model is obtained according to the historical model database, and the actual gap between the parts of the riveting die is compared with the matching gap between the parts of the design model to calculate the initial matching gap deviation of the riveting die. The specific calculation formula for the initial matching gap deviation of the riveting die is: ΔG = , where ΔG is the initial fit clearance deviation of the riveting die, is the actual gap between the parts of the riveting die, To design the clearance between the components of the model, the actual temperature of the riveting die is obtained through a temperature measuring instrument, the standard temperature of the design model is obtained according to the historical model database, and the temperature deviation of the riveting die is calculated based on the actual temperature and the standard temperature. The specific calculation formula is: ΔT = ; where ΔT is the temperature deviation, is the actual temperature of the riveting die, is the standard temperature of the design model; The initial accuracy of the riveting die is analyzed according to the fit clearance deviation ΔG and the temperature deviation ΔT, and the final initial accuracy of the riveting die is obtained by normalization and weighted calculation. The formula for normalizing the fit clearance deviation ΔG and the temperature deviation ΔT is: ; is the normalized fit clearance deviation, Allowable tolerance for fit clearance; ; is the normalized temperature deviation, is the temperature tolerance; the initial accuracy of the riveting die is calculated by combining the normalized fit clearance deviation and temperature deviation through a weighted formula. The specific formula is: U= + ; Among them, U is the initial accuracy of the riveting die, is the weight coefficient of the normalized fit clearance deviation, is the weight coefficient of normalized temperature deviation; The actual inner cavity depth of the rivet mold is obtained through a 3D scanning instrument, and the standard inner cavity depth of the design model is obtained through the historical model database. The change of the inner cavity depth of the rivet mold is obtained according to the actual inner cavity depth and the standard inner cavity depth. The specific calculation formula is: ΔD = ; Among them, ΔD is the change in the depth of the riveting mold cavity, is the actual inner cavity depth of the riveting die, is the standard inner cavity depth of the design model; the parting surface adjustment value of the corrected rivet mold is calculated according to the change of the inner cavity depth of the rivet mold. The specific calculation formula is ΔZ=ΔD×θ; where ΔZ is the parting surface adjustment value, ΔD is the change of the inner cavity depth of the rivet mold, is the parting surface angle; The weighted formula is used to comprehensively evaluate the riveting die status by combining the initial accuracy of the riveting die and the adjustment value of the parting surface. The specific formula is: Q=U× +ΔZ× ; Among them, Q is the riveting die state, is the weight of the initial accuracy of the riveting die, is the weight of the parting surface adjustment value.

2. The deformable SPR riveting die optimization method according to claim 1, characterized in that: By performing 3D scanning on the appearance and geometric shape of the riveting die and the riveted area, the 3D point cloud data of the riveting die is obtained, and the 3D point cloud data of the riveting die is processed. First, the 3D point cloud data is denoised, then the 3D point cloud data is registered, and then the 3D point cloud data is optimized. Finally, the 3D point cloud data is converted into a 3D model; The data of the design model is obtained through the historical model database, and the 3D point cloud data of the processed riveting die is compared with the design model using 3D comparison software to generate a deviation map. The data in the deviation map includes shape error data and geometric deviation data; According to the geometric shape and material properties of the design model, a finite element analysis model of the rivet die is established in the 3D software. The system inputs the data in the deviation diagram into the finite element analysis model to evaluate the rivet die.

3. The deformable SPR riveting die optimization method according to claim 1, characterized in that: Collect the inner cavity depth amplitude change values ​​of the historical revised riveting mold, and comprehensively evaluate the number of steps of the finite element analysis to detect the revised riveting mold according to the riveting mold state and the inner cavity depth amplitude change value; according to the data of the historical revised riveting mold, average the inner cavity depth changes of the historical revised riveting mold as the inner cavity depth amplitude change value of the historical revised riveting mold; The number of steps of finite element analysis for testing the modified riveting die was evaluated by fuzzy reasoning.

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