A method and system for detecting dimensional accuracy of mold forming parts

Abstract

The present invention discloses a dimensional accuracy detection method and system for mold forming parts, which relates to the field of dimensional detection technology, including: collecting the three-dimensional point coordinates of the mold and the part respectively through a surveying and mapping tool and summarizing and outputting them as a three-dimensional model; converting the three-dimensional model into a finite element model through finite element analysis; simulating the deformation process of the mold and the part to obtain the deformation law of the mold and the deformation law of the part; using a single deviation anti-compensation correction method to restore the three-dimensional model to a restored model; using an implicit surface reconstruction algorithm to reconstruct the restored model into a surface model; based on the horizontal coordinate, vertical coordinate and vertical coordinate of each point in the surface model, calculate and output the dimensional accuracy of the mold forming part. By setting a model construction module and an accuracy calculation module to find out the elastic deformation law of the mold and the elastic rebound law of the part, and then carrying out anti-compensation correction on the mold according to them, the accuracy of the mold forming parts can be effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of dimension detection, and in particular to a dimension accuracy detection method and system for mold forming parts. Background Art

[0002] After entering the 21st century, China's industry has developed rapidly, and higher requirements have been put forward for cold forging technology. With the development of cold forging technology, a large number of complex parts have been formed by cold forging. Although there is a great demand for parts, due to the complex shape, it is extremely difficult to form by cold forging. Most of them are solved by introducing production lines or imports. At present, the main contents of cold precision forging technology research are concentrated on deformation law, production process, mold design, improving product quality and precision control.

[0003] Domestic and foreign scholars have done a lot of research on the deformation law of cold precision forging, but due to the complex shape of parts, the cold forging forming mechanism is affected by many factors, and the deformation law needs further study. The research on production process and mold design is relatively mature, and many new processes and methods have been promoted to production practice. The quality of cold forged products is better than that of machined products. The main reason is that processing strengthening occurs during plastic deformation, the metal fibers are not destroyed, and the grains are refined. The research on precision control mainly improves the accuracy of parts by modifying the mold cavity. Summary of the invention

[0004] In order to solve the above technical problems, a method and system for detecting the dimensional accuracy of molded parts are provided. This technical solution solves the problems raised in the above background technology.

[0005] In order to achieve the above purpose, the technical solution adopted by the present invention is:

[0006] A method for detecting the dimensional accuracy of a molded part, comprising:

[0007] The three-dimensional point coordinates of the mold and parts are collected by surveying and mapping tools and summarized and output as a three-dimensional model of the mold and a three-dimensional model of the parts;

[0008] Through finite element analysis, the mold 3D model and the part 3D model are converted into a mold finite element model and a part finite element model respectively;

[0009] Based on the mold finite element model and the part finite element model, the deformation process of the mold and the part are simulated respectively to obtain the deformation law of the mold and the deformation law of the part;

[0010] Using the single deviation anti-compensation correction method, based on the mold deformation law and the part deformation law, the mold 3D model and the part 3D model are restored to the mold restoration model and the part restoration model;

[0011] The mold restoration model and the part restoration model are reconstructed into a mold surface model and a part surface model by using an implicit surface reconstruction algorithm;

[0012] Based on the horizontal coordinate, vertical coordinate and vertical coordinate of each point in the mold surface model and the part surface model, the dimensional accuracy of the molded part is calculated and output;

[0013] Determine whether the dimensional accuracy of the molded part is greater than a preset threshold. If so, output that the size of the molded part is qualified; if not, output that the size of the molded part is unqualified.

[0014] Preferably, the converting the mold three-dimensional model and the part three-dimensional model into the mold finite element model and the part finite element model respectively through finite element analysis specifically includes:

[0015] Define the geometric area of ​​the finite element model based on the mold 3D model and the part 3D model;

[0016] Enter the material properties of the mold and parts;

[0017] Connectivity of input finite element models;

[0018] Enter the boundary conditions of the finite element model;

[0019] Obtain the loads on each contact surface between the mold and the part during the mold forming process;

[0020] The summary output is the mold finite element model and the part finite element model.

[0021] Preferably, the simulating the deformation process of the mold and the part based on the mold finite element model and the part finite element model to obtain the mold deformation law and the part deformation law specifically includes:

[0022] Take at least two mold curves and part curves from one end to the other at the same interval on the mold and part, respectively, with at least two points evenly distributed on each curve, and the first point is at the vertex of the mold curve or part curve;

[0023] By tracking the changes in displacement information of these nodes before and after molding, the deformation law of the entire mold and parts can be analyzed;

[0024] During the molding process, the mold cavity is sunken by the reaction force. After the mold is removed from the part, the cavity wall will expand to the initial position, that is, to the center of the mold cavity.

[0025] During the forming process, the parts are subjected to plastic deformation due to the force, which leaves residual stress inside and on the surface of the blank. After forming, the residual stress is released and elastic rebound occurs.

[0026] The deformation of the mold and parts is the largest at the vertex, gradually decreases from the vertex to the middle, and reaches the minimum deformation at the widest point of the curve.

[0027] Preferably, the method of using the single deviation anti-compensation correction method to restore the mold three-dimensional model and the part three-dimensional model into the mold restoration model and the part restoration model based on the mold deformation law and the part deformation law specifically includes:

[0028] Based on the deformation law of mold and part, the deformation amount of mold and part at each point in the forming process is obtained;

[0029] The compensation is determined to be a single deviation, which is equal to the deformation of the mold and the part at each point during the molding process, but in the opposite direction;

[0030] According to the reverse compensation design scheme, the mold or the part is modified respectively to obtain the mold restoration model and the part restoration model.

[0031] Preferably, the step of reconstructing the mold restoration model and the part restoration model into a mold surface model and a part surface model by using an implicit surface reconstruction algorithm specifically includes:

[0032] Define the radial basis function as a Gaussian function;

[0033] Select at least one point in the restored model as the center point, and calculate the distance from each point in the restored model to the center point;

[0034] constructing an interpolation matrix using radial basis functions and the distance;

[0035] Construct a system of linear equations by setting the linear combination of radial basis functions equal to the known point coordinates;

[0036] Solving the linear equations to obtain the coefficients of the radial basis functions corresponding to each center point;

[0037] Define the implicit function as a linear combination of radial basis functions;

[0038] Decomposing the restored model into at least one cube;

[0039] Traverse the cubes in the restored model, and determine the zero isosurface of each cube according to the sign and size of the implicit function at each vertex of the cube;

[0040] Summarize and output the zero isosurfaces of all cubes as a surface model;

[0041] The Gaussian function is: ,

[0042] In the formula, , , are real constants, Enter the value for the Gaussian function, Output value for Gaussian function;

[0043] The implicit function is: ,

[0044] In the formula, is the coordinate of the i-th point in the restored model, is the coordinate of the jth center point, To restore the distance between the i-th point and the j-th center point in the model, is the coefficient of the radial basis function corresponding to the jth center point, is the number of points in the restored model, is the number of center points, is an implicit function.

[0045] Preferably, the calculating and outputting the dimensional accuracy of the molded part based on the horizontal coordinate, vertical coordinate and vertical coordinate of each point in the mold surface model and the part surface model specifically includes:

[0046] Obtain the horizontal coordinate, vertical coordinate and vertical coordinate of each point in the mold surface model and the part surface model;

[0047] Calculate the vertical coordinate difference of points with the same horizontal coordinate and vertical coordinate in the mold surface model and the part surface model;

[0048] The dimensional accuracy of the molded parts is calculated using the dimensional accuracy formula;

[0049] The dimensional accuracy formula is: ,

[0050] In the formula, For the dimensional accuracy of the molded parts, , They are the vertical coordinates of the points with the same horizontal and vertical coordinates in the mold surface model and the part surface model respectively.

[0051] Furthermore, a dimensional accuracy detection system for mold forming parts is proposed, which is used to implement the dimensional accuracy detection method for mold forming parts as described above, including:

[0052] A model building module, wherein the model building module is used to collect the three-dimensional point coordinates of the mold and the part respectively through a surveying and mapping tool and summarize and output them as a mold three-dimensional model and a part three-dimensional model, convert the mold three-dimensional model and the part three-dimensional model into a mold finite element model and a part finite element model respectively through finite element analysis, simulate the deformation process of the mold and the part respectively based on the mold finite element model and the part finite element model, obtain the mold deformation law and the part deformation law, use a single deviation anti-compensation correction method, based on the mold deformation law and the part deformation law, restore the mold three-dimensional model and the part three-dimensional model into a mold restoration model and a part restoration model, and use an implicit surface reconstruction algorithm to reconstruct the mold restoration model and the part restoration model into a mold surface model and a part surface model;

[0053] The precision calculation module is used to calculate and output the dimensional precision of the molded part based on the horizontal coordinate, vertical coordinate and vertical coordinate of each point in the mold surface model and the part surface model, and to determine whether the dimensional precision of the molded part is greater than a preset threshold.

[0054] Optionally, the model building module specifically includes:

[0055] A three-dimensional model building unit, which is used to collect three-dimensional point coordinates of the mold and the part respectively through a surveying and mapping tool and summarize and output them as a mold three-dimensional model and a part three-dimensional model;

[0056] A finite element model building unit, wherein the finite element model building unit is used to convert the mold three-dimensional model and the part three-dimensional model into a mold finite element model and a part finite element model respectively through finite element analysis;

[0057] A deformation law analysis unit, which is used to simulate the deformation process of the mold and the part respectively based on the mold finite element model and the part finite element model to obtain the mold deformation law and the part deformation law;

[0058] A restoration model building unit, wherein the restoration model building unit is used to restore the mold three-dimensional model and the part three-dimensional model into a mold restoration model and a part restoration model based on the mold deformation law and the part deformation law by using a single deviation anti-compensation correction method;

[0059] The surface model construction unit is used to reconstruct the mold restoration model and the part restoration model into a mold surface model and a part surface model by using an implicit surface reconstruction algorithm.

[0060] Optionally, the accuracy calculation module specifically includes:

[0061] An accuracy calculation unit, the accuracy calculation unit is used to calculate and output the dimensional accuracy of the molded part based on the horizontal coordinate, vertical coordinate and vertical coordinate of each point in the mold surface model and the part surface model;

[0062] The precision judgment unit is used to judge whether the dimensional precision of the molded part is greater than a preset threshold.

[0063] Compared with the prior art, the present invention has the following beneficial effects:

[0064] By setting up the model building module and the accuracy calculation module to find out the elastic deformation law of the mold and the elastic rebound law of the parts, and then carrying out anti-compensation correction on the mold based on them, the accuracy of the molded parts can be effectively improved. It also has important guiding significance for the production of parts. It not only ensures the dimensional accuracy of the parts, but also performs contact analysis on the modified parts, so that the parts obtained after the mold cavity is corrected fully meet the use requirements without causing excessive transmission errors. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] Figure 1 It is a flow chart of the dimensional accuracy detection method of the mold forming parts of the present invention;

[0066] Figure 2 A flow chart of the finite element model construction method of the present invention;

[0067] Figure 3 It is a flow chart of the deformation law analysis method of the present invention;

[0068] Figure 4 A flow chart of the reduction model construction method of the present invention;

[0069] Figure 5 A flow chart of the surface model construction method of the present invention;

[0070] Figure 6 It is a flow chart of the dimensional accuracy calculation method of the present invention. DETAILED DESCRIPTION

[0071] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are only examples, and those skilled in the art may think of other obvious variations.

[0072] Reference Figure 1 As shown, a method for detecting the dimensional accuracy of molded parts includes:

[0073] The three-dimensional point coordinates of the mold and parts are collected by surveying and mapping tools and summarized and output as a three-dimensional model of the mold and a three-dimensional model of the parts;

[0074] Through finite element analysis, the mold 3D model and the part 3D model are converted into a mold finite element model and a part finite element model respectively;

[0075] Based on the mold finite element model and the part finite element model, the deformation process of the mold and the part are simulated respectively to obtain the deformation law of the mold and the deformation law of the part;

[0076] Using the single deviation anti-compensation correction method, based on the mold deformation law and the part deformation law, the mold 3D model and the part 3D model are restored to the mold restoration model and the part restoration model;

[0077] The mold restoration model and the part restoration model are reconstructed into a mold surface model and a part surface model by using an implicit surface reconstruction algorithm;

[0078] Based on the horizontal coordinate, vertical coordinate and vertical coordinate of each point in the mold surface model and the part surface model, the dimensional accuracy of the molded part is calculated and output;

[0079] Determine whether the dimensional accuracy of the molded part is greater than a preset threshold. If so, output that the size of the molded part is qualified; if not, output that the size of the molded part is unqualified.

[0080] Reference Figure 2 As shown, through finite element analysis, the mold 3D model and the part 3D model are converted into the mold finite element model and the part finite element model respectively, specifically including:

[0081] Define the geometric area of ​​the finite element model based on the mold 3D model and the part 3D model;

[0082] Enter the material properties of the mold and parts;

[0083] Connectivity of input finite element models;

[0084] Enter the boundary conditions of the finite element model;

[0085] Obtain the loads on each contact surface between the mold and the part during the mold forming process;

[0086] The summary output is the mold finite element model and the part finite element model.

[0087] The finite element analysis method was originally called the matrix approximation method and was applied to the structural strength calculation of aircraft. Due to its convenience, practicality and effectiveness, it aroused great interest among scientists engaged in mechanics research. After just a few decades of hard work, with the rapid development and popularization of computer technology, the finite element method has quickly expanded from structural engineering strength analysis calculations to almost all fields of science and technology, becoming a colorful, widely used, practical and efficient numerical analysis method.

[0088] Reference Figure 3 As shown in the figure, based on the mold finite element model and the part finite element model, the deformation process of the mold and the part are simulated respectively, and the deformation laws of the mold and the part are obtained, which specifically include:

[0089] Take at least two mold curves and part curves from one end to the other at the same interval on the mold and part, respectively, with at least two points evenly distributed on each curve, and the first point is at the vertex of the mold curve or part curve;

[0090] By tracking the changes in displacement information of these nodes before and after molding, the deformation law of the entire mold and parts can be analyzed;

[0091] During the molding process, the mold cavity is sunken by the reaction force. After the mold is removed from the part, the cavity wall will expand to the initial position, that is, to the center of the mold cavity.

[0092] During the forming process, the parts are subjected to plastic deformation due to the force, which leaves residual stress inside and on the surface of the blank. After forming, the residual stress is released and elastic rebound occurs.

[0093] The deformation of the mold and parts is the largest at the vertex, gradually decreases from the vertex to the middle, and reaches the minimum deformation at the widest point of the curve.

[0094] Since both the parts and the mold are subjected to very large forces during the forming process, elastic deformation and elastic rebound will occur after the force on the mold is removed and the parts are ejected from the mold. These two elastic deformations are enough to have a great impact on the accuracy of the parts.

[0095] Reference Figure 4 As shown, using the single deviation anti-compensation correction method, based on the mold deformation law and the part deformation law, the mold 3D model and the part 3D model are restored to the mold restoration model and the part restoration model, which specifically includes:

[0096] Based on the deformation law of mold and part, the deformation amount of mold and part at each point in the forming process is obtained;

[0097] The compensation is determined to be a single deviation, which is equal to the deformation of the mold and the part at each point during the molding process, but in the opposite direction;

[0098] According to the reverse compensation design scheme, the mold or the part is modified respectively to obtain the mold restoration model and the part restoration model.

[0099] The single deviation back compensation correction method is a method used in the fields of manufacturing and engineering, especially in the mold design and manufacturing process, to correct the deviation caused by manufacturing errors, material characteristics or improper design. The core idea of ​​this method is to correct the shape of the mold or part by reversely applying a single multiple of the deviation in order to achieve the expected accuracy and performance.

[0100] Reference Figure 5 As shown, the mold restoration model and the part restoration model are reconstructed into a mold surface model and a part surface model using an implicit surface reconstruction algorithm, specifically including:

[0101] Define the radial basis function as a Gaussian function;

[0102] Select at least one point in the restored model as the center point, and calculate the distance from each point in the restored model to the center point;

[0103] constructing an interpolation matrix using radial basis functions and the distance;

[0104] Construct a system of linear equations by setting the linear combination of radial basis functions equal to the known point coordinates;

[0105] Solving the linear equations to obtain the coefficients of the radial basis functions corresponding to each center point;

[0106] Define the implicit function as a linear combination of radial basis functions;

[0107] Decomposing the restored model into at least one cube;

[0108] Traverse the cubes in the restored model, and determine the zero isosurface of each cube according to the sign and size of the implicit function at each vertex of the cube;

[0109] Summarize and output the zero isosurfaces of all cubes as a surface model;

[0110] The Gaussian function is: ,

[0111] In the formula, , , are real constants, Enter the value for the Gaussian function, Output value for Gaussian function;

[0112] The implicit function is: ,

[0113] In the formula, is the coordinate of the i-th point in the restored model, is the coordinate of the jth center point, To restore the distance between the i-th point and the j-th center point in the model, is the coefficient of the radial basis function corresponding to the jth center point, is the number of points in the restored model, is the number of center points, is an implicit function.

[0114] Implicit surface reconstruction is an important three-dimensional surface reconstruction technology. It represents the surface by defining an implicit function. The function takes negative values ​​inside the surface, positive values ​​outside the surface, and zero value on the surface. The core of implicit surface reconstruction is to construct an implicit function that can accurately describe the shape of the surface. This function is usually a continuous and differentiable scalar function, and its zero isosurface is the desired surface.

[0115] Reference Figure 6 As shown, based on the horizontal coordinate, vertical coordinate and vertical coordinate of each point in the mold surface model and the part surface model, the dimensional accuracy of the molded part is calculated and output specifically including:

[0116] Obtain the horizontal coordinate, vertical coordinate and vertical coordinate of each point in the mold surface model and the part surface model;

[0117] Calculate the vertical coordinate difference of points with the same horizontal coordinate and vertical coordinate in the mold surface model and the part surface model;

[0118] The dimensional accuracy of the molded parts is calculated using the dimensional accuracy formula;

[0119] The dimensional accuracy formula is: ,

[0120] In the formula, For the dimensional accuracy of the molded parts, , They are the vertical coordinates of the points with the same horizontal and vertical coordinates in the mold surface model and the part surface model respectively.

[0121] Based on the horizontal, vertical and vertical coordinates of each point in the mold surface model and the part surface model, the dimensional accuracy of the molded part is calculated and output, which can effectively obtain the difference between the two surface models and the proportion of the difference in the overall model.

[0122] Further, based on the same inventive concept as the above-mentioned method for detecting the dimensional accuracy of mold forming parts, the present solution also proposes a system for detecting the dimensional accuracy of mold forming parts, comprising:

[0123] A model building module, wherein the model building module is used to collect the three-dimensional point coordinates of the mold and the part respectively through a surveying and mapping tool and summarize and output them as a mold three-dimensional model and a part three-dimensional model, convert the mold three-dimensional model and the part three-dimensional model into a mold finite element model and a part finite element model respectively through finite element analysis, simulate the deformation process of the mold and the part respectively based on the mold finite element model and the part finite element model, obtain the mold deformation law and the part deformation law, use a single deviation anti-compensation correction method, based on the mold deformation law and the part deformation law, restore the mold three-dimensional model and the part three-dimensional model into a mold restoration model and a part restoration model, and use an implicit surface reconstruction algorithm to reconstruct the mold restoration model and the part restoration model into a mold surface model and a part surface model;

[0124] The precision calculation module is used to calculate and output the dimensional precision of the molded part based on the horizontal coordinate, vertical coordinate and vertical coordinate of each point in the mold surface model and the part surface model, and to determine whether the dimensional precision of the molded part is greater than a preset threshold.

[0125] The model building modules include:

[0126] A three-dimensional model building unit, which is used to collect three-dimensional point coordinates of the mold and the part respectively through a surveying and mapping tool and summarize and output them as a mold three-dimensional model and a part three-dimensional model;

[0127] A finite element model building unit, wherein the finite element model building unit is used to convert the mold three-dimensional model and the part three-dimensional model into a mold finite element model and a part finite element model respectively through finite element analysis;

[0128] A deformation law analysis unit, which is used to simulate the deformation process of the mold and the part respectively based on the mold finite element model and the part finite element model to obtain the mold deformation law and the part deformation law;

[0129] A restoration model building unit, wherein the restoration model building unit is used to restore the mold three-dimensional model and the part three-dimensional model into a mold restoration model and a part restoration model based on the mold deformation law and the part deformation law by using a single deviation anti-compensation correction method;

[0130] The surface model construction unit is used to reconstruct the mold restoration model and the part restoration model into a mold surface model and a part surface model by using an implicit surface reconstruction algorithm.

[0131] The precision calculation module specifically includes:

[0132] An accuracy calculation unit, the accuracy calculation unit is used to calculate and output the dimensional accuracy of the molded part based on the horizontal coordinate, vertical coordinate and vertical coordinate of each point in the mold surface model and the part surface model;

[0133] The precision judgment unit is used to judge whether the dimensional precision of the molded part is greater than a preset threshold.

[0134] Furthermore, the present solution also proposes a computer-readable storage medium on which a computer-readable program is stored. When the computer-readable program is called, the above-mentioned dimensional accuracy detection method for mold forming parts is executed.

[0135] It is understandable that the storage medium may be a magnetic medium, such as a floppy disk, a hard disk, or a magnetic tape; an optical medium, such as a DVD; or a semiconductor medium, such as a solid state drive (SSD).

[0136] To sum up, the advantages of the present invention are: by setting a model building module and an accuracy calculation module to find out the elastic deformation law of the mold and the elastic rebound law of the parts, and then carrying out anti-compensation correction on the mold based on them, the accuracy of the molded parts can be effectively improved, and it also has important guiding significance for the production of parts. It not only ensures the dimensional accuracy of the parts, but also performs contact analysis on the modified parts, so that the parts obtained after the mold cavity is corrected fully meet the use requirements without generating excessive transmission errors.

[0137] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions only describe the principles of the present invention. The present invention may be subject to various changes and improvements without departing from the spirit and scope of the present invention. These changes and improvements fall within the scope of the present invention. The scope of protection claimed by the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for detecting the dimensional accuracy of molded parts, characterized in that: include: The three-dimensional point coordinates of the mold and parts are collected by surveying and mapping tools and summarized and output as a three-dimensional model of the mold and a three-dimensional model of the parts; Through finite element analysis, the mold 3D model and the part 3D model are converted into a mold finite element model and a part finite element model respectively; Based on the mold finite element model and the part finite element model, the deformation process of the mold and the part are simulated respectively to obtain the deformation law of the mold and the deformation law of the part; Using the single deviation anti-compensation correction method, based on the mold deformation law and the part deformation law, the mold 3D model and the part 3D model are restored to the mold restoration model and the part restoration model; The mold restoration model and the part restoration model are reconstructed into a mold surface model and a part surface model by using an implicit surface reconstruction algorithm; Based on the horizontal coordinate, vertical coordinate and vertical coordinate of each point in the mold surface model and the part surface model, the dimensional accuracy of the molded part is calculated and output; Determine whether the dimensional accuracy of the molded part is greater than a preset threshold, if so, output that the size of the molded part is qualified, if not, output that the size of the molded part is unqualified; The deformation processes of the mold and the part are simulated based on the mold finite element model and the part finite element model, and the deformation laws of the mold and the part are obtained, which specifically include: Take at least two mold curves and part curves from one end to the other at the same interval on the mold and part, respectively, with at least two points evenly distributed on each curve, and the first point is at the vertex of the mold curve or part curve; By tracking the changes in displacement information of these nodes before and after molding, the deformation law of the entire mold and parts can be analyzed; During the molding process, the mold cavity is sunken by the reaction force. After the mold is removed from the part, the cavity wall will expand to the initial position, that is, to the center of the mold cavity. During the forming process, the parts are subjected to plastic deformation due to the force, which leaves residual stress inside and on the surface of the blank. After forming, the residual stress is released and elastic rebound occurs. The deformation of the mold and parts is the largest at the vertex, gradually decreases from the vertex to the middle, and reaches the minimum deformation at the widest point of the curve; The method of using the single deviation anti-compensation correction method to restore the mold 3D model and the part 3D model to the mold restoration model and the part restoration model based on the mold deformation law and the part deformation law specifically includes: Based on the deformation law of mold and part, the deformation amount of mold and part at each point in the forming process is obtained; The compensation is determined to be a single deviation, which is equal to the deformation of the mold and the part at each point during the molding process, but in the opposite direction; According to the reverse compensation design scheme, the mold or the part is modified respectively to obtain a mold restoration model and a part restoration model; The method of reconstructing the mold restoration model and the part restoration model into a mold surface model and a part surface model by using an implicit surface reconstruction algorithm specifically includes: Define the radial basis function as a Gaussian function; Select at least one point in the restored model as the center point, and calculate the distance from each point in the restored model to the center point; constructing an interpolation matrix using radial basis functions and the distance; Construct a system of linear equations by setting the linear combination of radial basis functions equal to the known point coordinates; Solving the linear equations to obtain the coefficients of the radial basis functions corresponding to each center point; Define the implicit function as a linear combination of radial basis functions; Decomposing the restored model into at least one cube; Traverse the cubes in the restored model, and determine the zero isosurface of each cube according to the sign and size of the implicit function at each vertex of the cube; Summarize and output the zero isosurfaces of all cubes as a surface model; The Gaussian function is: , In the formula, , , are real constants, Enter the value for the Gaussian function, Output value for Gaussian function; The implicit function is: , In the formula, is the coordinate of the i-th point in the restored model, is the coordinate of the jth center point, To restore the distance between the i-th point and the j-th center point in the model, is the coefficient of the radial basis function corresponding to the jth center point, is the number of points in the restored model, is the number of center points, is an implicit function.

2. A method for detecting dimensional accuracy of molded parts according to claim 1, characterized in that: The method of converting the mold three-dimensional model and the part three-dimensional model into a mold finite element model and a part finite element model respectively through finite element analysis specifically includes: Define the geometric area of ​​the finite element model based on the mold 3D model and the part 3D model; Enter the material properties of the mold and parts; Connectivity of input finite element models; Enter the boundary conditions of the finite element model; Obtain the loads on each contact surface between the mold and the part during the mold forming process; The summary output is the mold finite element model and the part finite element model.

3. A method for detecting dimensional accuracy of molded parts according to claim 2, characterized in that: The calculating and outputting the dimensional accuracy of the molded part based on the horizontal coordinate, the vertical coordinate and the vertical coordinate of each point in the mold surface model and the part surface model specifically includes: Obtain the horizontal coordinate, vertical coordinate and vertical coordinate of each point in the mold surface model and the part surface model; Calculate the vertical coordinate difference of points with the same horizontal coordinate and vertical coordinate in the mold surface model and the part surface model; The dimensional accuracy of the molded parts is calculated using the dimensional accuracy formula; The dimensional accuracy formula is: , In the formula, For the dimensional accuracy of the molded parts, , They are the vertical coordinates of the points with the same horizontal and vertical coordinates in the mold surface model and the part surface model respectively.

4. A dimensional accuracy detection system for mold forming parts, used to implement the dimensional accuracy detection method for mold forming parts according to any one of claims 1 to 3, characterized in that: include: A model building module, wherein the model building module is used to collect three-dimensional point coordinates of the mold and the part respectively through a surveying and mapping tool and summarize and output them as a mold three-dimensional model and a part three-dimensional model, convert the mold three-dimensional model and the part three-dimensional model into a mold finite element model and a part finite element model respectively through finite element analysis, simulate the deformation process of the mold and the part respectively based on the mold finite element model and the part finite element model, obtain the mold deformation law and the part deformation law, use a single deviation anti-compensation correction method, based on the mold deformation law and the part deformation law, restore the mold three-dimensional model and the part three-dimensional model into a mold restoration model and a part restoration model, and use an implicit surface reconstruction algorithm to reconstruct the mold restoration model and the part restoration model into a mold surface model and a part surface model; The precision calculation module is used to calculate and output the dimensional precision of the molded part based on the horizontal coordinate, vertical coordinate and vertical coordinate of each point in the mold surface model and the part surface model, and to determine whether the dimensional precision of the molded part is greater than a preset threshold.

5. A dimensional accuracy detection system for mold forming parts according to claim 4, characterized in that: The model building module specifically includes: A three-dimensional model building unit, which is used to collect three-dimensional point coordinates of the mold and the part respectively through a surveying and mapping tool and summarize and output them as a mold three-dimensional model and a part three-dimensional model; A finite element model building unit, wherein the finite element model building unit is used to convert the mold three-dimensional model and the part three-dimensional model into a mold finite element model and a part finite element model respectively through finite element analysis; A deformation law analysis unit, which is used to simulate the deformation process of the mold and the part respectively based on the mold finite element model and the part finite element model to obtain the mold deformation law and the part deformation law; A restoration model building unit, wherein the restoration model building unit is used to restore the mold three-dimensional model and the part three-dimensional model into a mold restoration model and a part restoration model based on the mold deformation law and the part deformation law by using a single deviation anti-compensation correction method; The surface model construction unit is used to reconstruct the mold restoration model and the part restoration model into a mold surface model and a part surface model by using an implicit surface reconstruction algorithm.

6. A dimensional accuracy detection system for mold forming parts according to claim 5, characterized in that: The accuracy calculation module specifically includes: An accuracy calculation unit, the accuracy calculation unit is used to calculate and output the dimensional accuracy of the molded part based on the horizontal coordinate, vertical coordinate and vertical coordinate of each point in the mold surface model and the part surface model; The precision judgment unit is used to judge whether the dimensional precision of the molded part is greater than a preset threshold.

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