Automatic modeling reconstruction method for edge corners of blank holder molded surface of stamping die

Abstract

The invention provides an automatic modeling reconstruction method for a side corner of a blank holder profile of a stamping die, and relates to the technical field of die design. Any point is selected from outer boundary curves on two sides of an end point of the side corner as a demarcation point, and the demarcation point is connected to form a demarcation line; two working planes are generated according to curved surface normal lines of the corner end points and the two demarcation points; selecting a first working plane, and modifying the feature points between the corner endpoints and the first demarcation point to obtain a reconstructed B-spline boundary curve; projecting the feature points and the reconstruction curve to a second working plane along a boundary to obtain projection feature points and a projection boundary curve; the projection vector line is used as the section line, the curved surface boundary at the boundary is used as the external boundary in combination with the reconstruction curve and the projection boundary curve, the corner modeling curved surface is reconstructed, the problems that the blank holder molded surface design is low in efficiency, high in error rate and difficult to cope with complex molded surface design are solved, the design efficiency is improved, the design error is reduced, and the design cost is reduced. And the optimization of the complex molded surface can be quickly and accurately completed.

Description

Technical Field

[0001] The invention relates to the technical field of mold design, and in particular to an automatic modeling reconstruction method for the corners of a blank holder ring profile of a stamping mold. Background Art

[0002] In the field of stamping die manufacturing, the blank holder is a key component of the stamping die, and its design is crucial to prevent the material from wrinkling during the drawing process. The design of the blank holder profile affects the fluidity of the material, which directly affects the quality and precision of the stamped parts. Traditional blank holder profile design usually relies on experience and manual CAD operations to adjust the profile shape, especially in the corner areas of the profile, which usually requires precise modeling to ensure uniform distribution of the material and prevent excessive deformation. In the existing design process, corner modeling usually requires complex CAD commands and multiple manual interventions to achieve the required accuracy. In addition, for complex profiles such as double-barrel "S" profiles, traditional methods are not only time-consuming but also often difficult to achieve the expected design requirements at one time, which greatly increases the number of design iterations and production preparation time.

[0003] In summary, the existing stamping die blank holder profile design is highly dependent on manual operation, resulting in low efficiency, high error rate, and difficulty in meeting technical problems such as complex profile design requirements. Summary of the invention

[0004] The present application provides an automated modeling reconstruction method for the corners of the blank holder ring profile of a stamping die, which is used to solve the technical problems that the existing stamping die blank holder ring profile design is highly dependent on manual operation, resulting in low efficiency, high error rate, and difficulty in meeting complex profile design requirements.

[0005] The present application provides an automated modeling and reconstruction method for the corners of a blank holder of a stamping die, the method comprising:

[0006] Extract the corner endpoints of the outer boundary curve of the pressure ring surface, and select any point on the extension direction of the outer boundary curve on both sides of the corner endpoint as the dividing point to obtain the first dividing point and the second dividing point; connect the first dividing point and the second dividing point to generate a dividing line, and cut off the corner surface outside the dividing line; generate a first working plane with the surface normal of the corner endpoint and the first dividing point, and generate a second working plane with the surface normal of the corner endpoint and the second dividing point; select the first working plane, add or delete feature points between the corner endpoint and the first dividing point, and obtain a reconstructed B-spline boundary curve; project the feature points and the reconstructed B-spline boundary curve onto the second working plane along the dividing line direction to obtain the projected feature points and the projected boundary curve; use the projection vector line between the feature point and the projected feature point as the section line, combine the reconstructed B-spline boundary curve and the projected boundary curve, take the surface boundary at the dividing line as the external boundary, and reconstruct the corner modeling surface.

[0007] One or more technical solutions provided in this application have at least the following technical effects or advantages:

[0008] The present application provides an automated modeling and reconstruction method for the corners of a blank holder ring profile of a stamping die. The method comprises the following steps: extracting the corner endpoints of the outer boundary curve of the blank holder ring profile, selecting any point on the extension direction of the outer boundary curve on both sides of the corner endpoint as a dividing point, and obtaining a first dividing point and a second dividing point; connecting the first dividing point and the second dividing point to generate a dividing line, and cutting off the corner surface outside the dividing line; generating a first working plane using the surface normals of the corner endpoint and the first dividing point, and generating a second working plane using the surface normals of the corner endpoint and the second dividing point; selecting the first working plane, adding or deleting feature points between the corner endpoint and the first dividing point, and obtaining a reconstructed B-spline boundary curve; and adding or deleting feature points between the feature points and the reconstructed B-spline boundary curve along the dividing line. The method is to project the shape of the corners of the mold onto the second working plane in the direction of the projected feature point and the projected boundary curve; the projection vector line between the feature point and the projected feature point is used as the section line, and the reconstructed B-spline boundary curve and the projected boundary curve are combined, and the surface boundary at the dividing line is used as the external boundary to reconstruct the corner modeling surface, thereby solving the technical problems that the existing stamping die pressure ring surface design is highly dependent on manual operation, resulting in low efficiency, high error rate, and difficulty in meeting the requirements of complex surface design. Through the technology of automatically reconstructing and deforming B-spline boundary curves, automatically generating section lines, and creating complex surfaces at one time, the technical effect of improving design efficiency, reducing design errors, and quickly and accurately completing the optimization of complex surfaces is achieved, thereby improving the design quality and production efficiency of the mold. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1A schematic flow chart of a method for automated modeling reconstruction of the corners of the blank holder ring profile of a stamping die is provided for this application. DETAILED DESCRIPTION

[0010] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0011] Examples, such as Figure 1 As shown, the present application provides an automatic modeling reconstruction method for the corners of the blank holder of a stamping die, the method comprising:

[0012] Step S100: extracting the corner endpoints of the outer boundary curve of the blank holder profile, and selecting any point on both sides of the corner endpoint in the extension direction of the outer boundary curve as a dividing point to obtain a first dividing point and a second dividing point.

[0013] The stamping die used for deep drawing mainly consists of three parts: the punch, the die and the blank holder. Among them, the blank holder is a clamping device set to prevent the stamping product from wrinkling during the deep drawing process, which is used to suppress the inflow of materials. The quality of the blank holder directly affects the quality of the stamping part, the utilization rate of the sheet material and the mold production and debugging cycle. Reasonable blank holder shape can not only improve the cracking and wrinkling during the deep drawing process, but also help to improve the material utilization rate and control the product rebound. Therefore, the blank holder profile design has become a key link in the process profile design of the stamping die.

[0014] In order to meet the requirements of refined design of process profiles, for complex blank holder profiles, designers usually need to make multiple rounds of repeated surface adjustments to the blank holder profiles based on design experience or simulation analysis results, especially the profile shaping of the corner areas of the blank holder profiles, which will directly affect the drawing height and sheet utilization of the stamping parts, and is the focus of blank holder profile adjustment and optimization. The corner shaping of the blank holder profiles usually adopts an extensible profile shape, such as a single-cylinder or double-cylinder "S" shape, otherwise the sheet metal will accumulate and wrinkle when the blank holder is closed, affecting the surface quality of the stamping parts.

[0015] The existing reconstruction of the shape of the edge corners of the blank holder ring profile is usually completed through professional CAD design software. However, since CAD software lacks the customized special commands required for process profile design, the design work will rely heavily on the designer's industry experience and require a large amount of manual modeling operations, which is time-consuming and laborious. Moreover, the customized special commands used for the shape of the edge corners of the blank holder ring profile in existing stamping professional software (such as Autoform, Dynaform, etc.) also use the "surface chamfering" method designed by CAD. One command operation can only create a single-cylinder shape, and it is impossible to complete the creation of a double-cylinder "S" shape at one time, and it is not convenient for the later adjustment and optimization of the double-cylinder "S" profile. It can be seen that the current stamping industry software has not yet provided a modeling method for quickly reconstructing the shape of the edge corners of the blank holder ring profile, especially for creating a double-cylinder "S" profile at one time. Therefore, this application proposes an automated shape reconstruction method for the edge corners of the blank holder ring profile of a stamping die to solve the limitations of the above-mentioned design operations.

[0016] Specifically, the corner endpoints of the outer boundary curve of the blank holder profile are first extracted. This process is to determine the specific starting position of the curve in the corner part. The corner endpoints are the key positions where the curve changes, and are usually the key parts that need to be dealt with in surface design. Once the corner endpoints are determined, then on the outer boundary curves on both sides of the corner endpoints, any point is selected along the extension direction of the curve. These two points are defined as the first dividing point and the second dividing point, respectively. Here, the selection of the dividing point is based on the need to ensure that the surface reconstruction area can be effectively controlled, and it also provides a basis for subsequent surface excision and reconstruction. The setting of the dividing point is not only related to the accuracy of the final surface, but also directly affects the use effect and production efficiency of the mold.

[0017] For example, if the corner of the original blank holder profile is an acute angle or has a complex geometric shape, the technical difficulty of the mold manufacturing process can be effectively simplified by accurately setting the dividing points while ensuring the quality of the molded parts. The selection of these dividing points usually needs to be based on detailed design data and simulation analysis results to ensure that the design and production processes can be optimized to the maximum extent without sacrificing product performance.

[0018] Through the above steps, not only the key operating area of ​​the blank holder profile is accurately defined, but also the surface design process is simplified through a systematic approach, thereby improving the surface modeling quality and production reliability.

[0019] Step S200: connecting the first dividing point and the second dividing point to generate a dividing line, and cutting off the corner surface outside the dividing line.

[0020] Furthermore, the corner curved surface outside the dividing line refers to the blank holder profile including the corner end point portion after being divided by the dividing line.

[0021] Optionally, the first dividing point and the second dividing point are connected by a straight line to form a dividing line, which is used to delimit the corner area, and divides the corner surface of the blank holder profile into two parts, namely, the area where no operation is performed and the corner surface outside the dividing line where the surface operation needs to be performed. The generation of this dividing line is performed in the extension direction of the outer boundary curve around the corner endpoint to ensure that the dividing line can accurately cover all areas that need to be processed.

[0022] Furthermore, the dividing line is not only the basic reference line for surface reconstruction, but also determines the range of the corner surface removal in subsequent operations. In actual operation, the accurate setting of the dividing line can effectively separate the area that needs to be reconstructed and ensure that its shape meets the design requirements. In the present invention, the corner surfaces outside the dividing line refer to those areas of the blank holder profile that still include the corner endpoints after being divided by the dividing line. These corner surfaces will be selectively removed under the action of the dividing line to remove unnecessary or redundant surface parts, thereby making room for the reconstruction and optimization of new surfaces. For example, in a design, if there is excess material or a surface that does not meet the design requirements in the corner area, precise shape adjustment can be achieved by connecting the dividing points and removing the corner surfaces outside the dividing line. This step not only ensures that the shape of the corner area meets the subsequent design requirements, but also improves the manufacturing accuracy of the mold, and ultimately achieves higher quality stamping parts.

[0023] Through the above steps, the corner areas of the blank holder profile can be efficiently processed, providing a solid foundation for the reconstruction of complex surfaces while optimizing the design and manufacturing process.

[0024] Step S300: Generate a first working plane using the surface normals of the corner endpoints and the first demarcation point, and generate a second working plane using the surface normals of the corner endpoints and the second demarcation point.

[0025] Furthermore, the first dividing point is in a first working plane, the second dividing point is in a second working plane, the first working plane and the second working plane have an intersection line, and the corner endpoint is on the intersection line of the two planes.

[0026] Exemplarily, after removing the original corner surface, a first working plane is generated based on the surface normals of the corner endpoints and the first demarcation point, and a second working plane is generated based on the surface normals of the corner endpoints and the second demarcation point. Specifically, a working plane refers to a plane defined in three-dimensional space for simplifying and controlling surface design, which provides an accurate reference surface through its relationship with the surface normals. In the present invention, the generation of a working plane is to perform operations on curves and feature points within a specific design area. During operation, the first working plane is defined by the surface normals of the corner endpoints and the first demarcation point, and this plane coincides with the surface normals of the corner endpoints, and its position is determined by the relative positions of the corner endpoints and the first demarcation point. Similarly, the second working plane is defined by the surface normals of the corner endpoints and the second demarcation point, ensuring that it is consistent with the surface normals of the corner endpoints and the second demarcation point.

[0027] Furthermore, the first demarcation point should be located in the first working plane, and the second demarcation point should be located in the second working plane. This configuration ensures that the settings of the two working planes can accurately cover the demarcation area, and an accurate geometric reference is provided through the intersection of the two working planes. Specifically, the intersection of the first working plane and the second working plane is the line formed by the intersection of the two planes, and all points on this line can be used as the basis for further operations. Under this setting, the corner endpoints are exactly located on the intersection of the first working plane and the second working plane. This setting ensures that the curve operations performed on these planes have good geometric alignment. For example, this configuration allows designers to accurately adjust and optimize the shape of the curve when dealing with corner areas, so that the final surface design can be more accurate and meet the design requirements.

[0028] Through the above steps, a systematic design framework is provided, which makes the surface design and adjustment process more efficient and accurate, especially in the processing of complex geometric shapes, ensuring the accuracy of design and high quality of manufacturing.

[0029] Step S400: Select the first working plane, add or delete feature points between the corner endpoint and the first dividing point, and obtain a reconstructed B-spline boundary curve.

[0030] Furthermore, before reconstructing the B-spline boundary curve, the working plane selected is any one of the first working plane and the second working plane.

[0031] Furthermore, the number of feature points added or deleted is multiple.

[0032] Specifically, the first working plane is selected, and feature points between the corner endpoints and the first dividing point are added or deleted on the plane to obtain a reconstructed B-spline boundary curve. The feature points refer to key points on the curve for controlling the shape of the curve. By adding or deleting these feature points, the designer can accurately adjust the shape of the curve to meet the design requirements.

[0033] Before performing the operation of adding or deleting feature points, the selected operation work plane can be either the first work plane or the second work plane. Selecting a suitable work plane helps to optimize the setting position of the feature points, thereby better controlling the shape and structure of the curve. For example, if the geometric features of the corner area are more obvious on the first work plane, the first work plane is preferred for operation; in some cases, the second work plane may be more suitable for the adjustment of feature points.

[0034] Furthermore, the feature points added or deleted are not just single points, but multiple points. These feature points are set to enable the reconstructed B-spline boundary curve to better approximate and meet the actual design requirements. By adjusting multiple feature points, a smooth B-spline boundary curve that meets the design requirements can be formed between the corner endpoint and the first dividing point. The addition and deletion operations of these feature points enable the curve to flexibly adjust its shape, ensuring the continuity and smoothness of the surface. For example, when designing a complex mold corner, by accurately adding several feature points on the first working plane, the B-spline curve can maintain an ideal curvature and shape when passing through the corner area, which not only improves the design accuracy, but also ensures the quality of the final mold.

[0035] Through the above steps, the boundary curves of the corner surfaces can be accurately reconstructed, thus providing a more reliable foundation for subsequent surface optimization and mold manufacturing.

[0036] Furthermore, the reconstructed B-spline boundary curve is based on the unit tangent vectors of the two end points of the curve. The coordinates of the given feature points are used as parameters to construct the geometrically universal cubic B-spline curve parametric equation:

[0037]

[0038] Where P(u) is a point on the curve defined by parameter u, and d i is the i-th control vertex, N i,3 (u) is the ith B-spline basis function of degree 3, n is the number of given feature points, is the tangent direction vector of the curve at the starting point, It refers to the tangent direction vector of the curve at the end point.

[0039] Exemplarily, a new B-spline boundary curve P(u) is constructed by adjusting the positions of the corner endpoints and a series of feature points. These feature points are obtained by the B-spline basis function N i,3 The curve is defined by the weighted sum of (u), where each control point d i The B-spline boundary curve P(u) is a smooth curve constructed using basis functions and control points, which is suitable for the precise description and control of complex shapes. i The points that determine the shape of the B-spline curve. By adjusting the positions of these points, the shape and characteristics of the curve can be changed; basis function N i,3 (u) determines the contribution and influence range of each control point to the curve.

[0040] In the process of reconstructing the B-spline boundary curve, the unit tangent vectors of the two end points of the curve are first determined and These tangent vectors have a decisive influence on the shape of the curve at the beginning and end. The tangent vectors are set based on the geometric characteristics of the curve at the corner end points to ensure that the curve smoothly transitions to or starts from the corner area. Then, the formula u∈[0,1] calculates the B-spline curve. In this process, each control point d i The positions of the control points are precisely adjusted to meet the design accuracy requirements. The position adjustment of these control points is based on detailed design evaluation and simulation analysis to ensure that the final surface not only meets the technical specifications, but also achieves the expected function and aesthetics. For example, when designing a blank holder for a car door panel, by accurately setting the control points of the B-spline curve, a smooth transition and precise docking of the door panel edge can be ensured. and The setting ensures a seamless connection from the body to the edge of the door panel, avoiding sharp edges or unnecessary bumps, thereby optimizing overall safety and aesthetics.

[0041] Through the above description, not only an efficient method is provided to reconstruct the corner area of ​​the blank holder profile, but also a systematic design process is used to ensure the high accuracy and repeatability of the curve, which adapts to the dual requirements of precision and efficiency in modern manufacturing.

[0042] Further, obtaining the reconstructed B-spline boundary curve, before, includes:

[0043] The positions of the corner endpoints are adjusted to obtain updated first working plane and second working plane.

[0044] The positions of multiple feature points in the updated first working plane are adjusted to obtain a reconstructed B-spline boundary curve.

[0045] Specifically, the process of reconstructing the B-spline boundary curve begins with the precise adjustment of the position of the corner endpoints. The corner endpoints are crucial starting points in curve design, and the accuracy of their positions directly affects the accuracy and functional realization of the entire curve. By adjusting the positions of the corner endpoints, it is possible to ensure that the curve better adapts to the design requirements, thereby improving the quality and performance of the final product. By precisely adjusting the positions of the corner endpoints, the first and second working planes are updated. The purpose of updating the working plane is to provide a reference plane that better meets the current design requirements, so that more detailed curve and feature point adjustments can be made on this basis. This step is crucial because all subsequent design adjustments will depend on the accuracy of these preliminary settings. Subsequently, in the updated first working plane, the positions of multiple feature points are adjusted. The adjustment of these feature points is to form a B-spline boundary curve that meets the new design requirements. By precisely controlling the positions of these feature points, it is possible to ensure that the new B-spline curve not only meets the specifications geometrically, but also meets the specific application requirements functionally.

[0046] This systematic design approach ensures that design goals can be achieved quickly and accurately in complex design environments, thereby significantly improving production efficiency and product quality.

[0047] Step S500: Projecting the feature points and the reconstructed B-spline boundary curve onto the second working plane along the direction of the dividing line to obtain projected feature points and a projected boundary curve.

[0048] Furthermore, the adjusted feature points and the reconstructed B-spline boundary curve are projected onto the second working plane along the previously defined dividing line direction. This operation is not only to synchronize the design information on the two working planes, but also to ensure the consistency and symmetry of the overall design. The projected feature points are image points of the original feature points on another working plane, generated by mathematical projection operations; the projected boundary curve is the corresponding curve of the original B-spline boundary curve on another working plane, reflecting the geometric properties of the original curve on the new plane.

[0049] Specifically, first, determine the direction of projection, that is, along the dividing line between the first working plane and the second working plane. The selection of this projection direction is based on the need to ensure the geometric symmetry and functional consistency of the design. Subsequently, the feature points and B-spline boundary curves on the first working plane are projected onto the second working plane in this direction using the projection tool of the computer-aided design (CAD) software. After completing the projection of the feature points and the B-spline boundary curves, the obtained projected feature points and projected boundary curves will be reconstructed on the second working plane, which not only ensures the symmetry and consistency of the design, but also helps engineers to review and adjust possible errors and inconsistencies in the design. In this way, the advantages of CAD technology can be effectively utilized, human errors can be reduced, and the efficiency and quality of design and manufacturing can be improved.

[0050] Through the above steps, high-precision and high-quality design output can be achieved in complex engineering applications, meeting the high standards of modern industrial manufacturing.

[0051] Step S600: using the projection vector line between the feature point and the projected feature point as the section line, combining the reconstructed B-spline boundary curve and the projected boundary curve, taking the surface boundary at the dividing line as the external boundary, and reconstructing the corner modeling surface.

[0052] Then, the projection vector line between the feature point and the projected feature point is used as the section line, and the reconstructed B-spline boundary curve and the projected boundary curve are further combined, and finally the surface boundary at the dividing line is set as the external boundary for reconstructing the corner modeling surface. This step is intended to generate smooth and accurate corner surfaces to meet design requirements. Among them, the projection vector line is a vector formed by the feature point and its corresponding projected feature point, which represents the geometric relationship between the two points and is used to generate the section line; the section line refers to the line generated along the projection vector line, which is used to divide and define the shape of the surface; the external boundary is formed by the surface boundary at the dividing line, which serves as the boundary condition for surface reconstruction to ensure that the reconstructed surface is consistent with other parts of the overall design.

[0053] In actual operation, the projected vector lines between the feature points and the projected feature points are first used to generate section lines. This method can realize the transformation of geometric relationships on different working planes and ensure the coordination of the shape of the surface between the two planes. The generated section lines will serve as an important reference in the surface reconstruction process to help accurately define the geometric features of the surface. Next, the reconstructed B-spline boundary curves and the projected boundary curves are combined to gradually reconstruct the new surface through the interaction of these geometric elements. The B-spline boundary curves ensure the smooth transition and detail control of the surface, while the projected boundary curves ensure the geometric consistency between different working planes. Through the integration of these curves, it can be ensured that the reconstructed surface has the smoothness and accuracy required for the design. Finally, the new external boundary conditions are set by the surface boundary at the dividing line to ensure that the reconstructed corner modeling surface is smooth and seamless when connected with other surfaces. This operation step will adjust the shape of the surface boundary so that it can naturally transition to the adjacent geometric parts, avoiding the possible unevenness or discontinuity at the surface connection.

[0054] This systematic surface reconstruction method not only improves the accuracy and flexibility of surface design, but also simplifies the modeling process of complex corner areas, significantly improving design efficiency and manufacturing quality.

[0055] Furthermore, the method further comprises:

[0056] Key feature points are selected on the boundary curve of the reconstructed corner modeling surface to obtain multiple key feature points.

[0057] The cross-section lines corresponding to the key feature points are obtained to segment the reconstructed corner modeling surfaces, and multiple surface profiles after the corner modeling of the blank holder ring profile is reconstructed are obtained.

[0058] Specifically, the key feature points are selected on the boundary curve of the reconstructed corner modeling surface to obtain multiple key feature points. These key feature points are important control points in the design, which determine the shape and transition relationship of the surface in the local area. By accurately selecting these points, the smoothness and geometric accuracy of the surface can be further ensured. The key feature points are points that have an important control role on the boundary curve or surface. The position and number of these points directly affect the shape and geometric characteristics of the surface; and surface segmentation refers to the division of a larger complex surface into multiple smaller surfaces that are easier to handle through section lines, so as to make more precise adjustments and optimizations.

[0059] Specifically, multiple key feature points are selected on the boundary curve of the reconstructed corner modeling surface. The selection of these feature points is usually based on design requirements and geometric characteristics. For example, feature points are selected in areas where the curvature changes significantly or in parts where the design requires fine control. By selecting these key points, the change of the surface shape can be effectively controlled to ensure that the transition of the corner area in all directions can meet the design requirements. Next, the section lines corresponding to each key feature point are obtained. These section lines are generated along the specified direction by the key feature points and are usually used to segment complex corner surfaces. The generation of section lines ensures that the surface can be accurately controlled and adjusted in multiple directions. With the assistance of these section lines, the reconstructed corner modeling surface can be effectively segmented into multiple surface segments, so that complex geometric forms can be handled more flexibly. Finally, the reconstructed corner modeling surface is segmented by obtaining the section lines corresponding to the key feature points to form multiple surface profiles. These segmented surface segments can be more accurately adjusted locally to ensure the smooth transition and geometric consistency of the overall surface. At the same time, through independent control of multiple surface segments, each detail in mold manufacturing can be optimized, errors can be reduced, and production efficiency and finished product quality can be improved.

[0060] Through this refined design and segmentation method, not only the design flexibility and accuracy of complex corner areas are greatly improved, but also the mold adjustment and manufacturing process in the production process can be significantly optimized to meet the dual requirements of high precision and high efficiency in the modern manufacturing industry.

[0061] Through the technical solutions of the above-mentioned embodiments, the present application provides an automated modeling reconstruction method for the corners of the blank holder ring profile of a stamping die, which solves the technical problems that the existing design of the blank holder ring profile of the stamping die is highly dependent on manual operation, resulting in low efficiency, high error rate, and difficulty in meeting the requirements of complex profile design. Through the technology of automated reconstruction and deformation of B-spline boundary curves, automatic generation of section lines, and one-time creation of complex profiles, the technical effect of improving design efficiency, reducing design errors, and quickly and accurately completing the optimization of complex profiles is achieved, thereby improving the design quality and production efficiency of the mold.

[0062] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0063] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application.

Claims

1. An automated modeling and reconstruction method for the corners of a blank holder of a stamping die, characterized in that: The method comprises: Step S100: extracting the corner endpoints of the outer boundary curve of the blank holder profile, and taking any point on both sides of the corner endpoint in the extension direction of the outer boundary curve as a dividing point to obtain a first dividing point and a second dividing point; Step S200: Connect the first dividing point and the second dividing point to generate a dividing line, and cut off the corner surface outside the dividing line; Step S300: generating a first working plane by using the surface normals of the corner endpoints and the first demarcation point, and generating a second working plane by using the surface normals of the corner endpoints and the second demarcation point; Step S400: Selecting the first working plane, adding or deleting feature points between the corner endpoint and the first dividing point, and obtaining a reconstructed B-spline boundary curve; Step S500: projecting the feature points and the reconstructed B-spline boundary curve onto the second working plane along the direction of the dividing line to obtain projected feature points and a projected boundary curve; Step S600: using the projection vector line between the feature point and the projected feature point as the section line, combining the reconstructed B-spline boundary curve and the projected boundary curve, taking the surface boundary at the dividing line as the external boundary, and reconstructing the corner modeling surface.

2. The method for automatically reconstructing the corners of the blank holder of a stamping die according to claim 1, characterized in that: The corner curved surface outside the dividing line refers to the pressure ring profile including the corner end point portion after being divided by the dividing line.

3. The method for automatically reconstructing the corners of the blank holder of a stamping die according to claim 1, characterized in that: The first dividing point is in the first working plane, the second dividing point is in the second working plane, the first working plane and the second working plane have an intersection line, and the corner endpoint is on the intersection line of the two planes.

4. The method for automatically reconstructing the corners of the blank holder of a stamping die according to claim 1, characterized in that: Before reconstructing the B-spline boundary curve, the working plane selected is any one of the first working plane and the second working plane.

5. The method for automatically reconstructing the corners of the blank holder of a stamping die according to claim 1, characterized in that: The reconstructed B-spline boundary curve is based on the unit tangent vectors of the two end points of the curve. The coordinates of the given feature points are used as parameters to construct the geometrically universal cubic B-spline curve parametric equation: Where Pu is a point on the curve defined by parameter u, d i is the i-th control vertex, N i,3 (u) is the ith B-spline basis function of degree 3, n is the number of given feature points, is the tangent direction vector of the curve at the starting point, It refers to the tangent direction vector of the curve at the end point.

6. The method for automatically reconstructing the corners of the blank holder of a stamping die according to claim 1, characterized in that: The added or deleted feature points are multiple.

7. The method for automatically reconstructing the corners of the blank holder of a stamping die according to claim 6, characterized in that: Obtain the reconstructed B-spline boundary curve, previously, including: Adjusting the positions of the corner endpoints to obtain updated first working plane and second working plane; The positions of multiple feature points in the updated first working plane are adjusted to obtain a reconstructed B-spline boundary curve.

8. The method for automatically reconstructing the corners of the blank holder of a stamping die according to claim 1, characterized in that: The method further comprises: Select key feature points on the boundary curve of the reconstructed corner modeling surface to obtain multiple key feature points; The cross-section lines corresponding to the key feature points are obtained to segment the reconstructed corner modeling surfaces, and multiple surface profiles after the corner modeling of the blank holder ring profile is reconstructed are obtained.

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