Car body stamping parts forming method based on combined stamping

Abstract

The present invention relates to the field of stamping forming control technology, and in particular to a vehicle body stamping part forming method based on combined stamping. The present invention obtains the target contour of the part to be stamped and the position of the ejector pin set on the stamping die in advance, and determines the surface sub-contour corresponding to the rigid support risk point in the target contour, determines the forming characterization vector of the surface sub-contour that conforms to the spatial position correlation relationship, determines the forming joint quantization area according to the comparison analysis result of the forming characterization vector, determines the forming collaborative characterization amount by comparing the vector comparison result based on the sub-area within the forming joint quantization area after the pre-stamping is completed, and finally adjusts the ejection duration of the pre-ejection ejector pin according to the forming collaborative characterization amount. The present invention realizes the joint analysis of the rigid forming of the stamping edge and scientifically optimizes the ejection action of the ejector pin, thereby realizing precise control and coordinated optimization of the stamping process.

Description

Technical Field

[0001] The present invention relates to the technical field of stamping forming control, and in particular to a vehicle body stamping part forming method based on combined stamping. Background Art

[0002] In the field of automobile manufacturing, the forming quality of body stamping parts is directly related to the safety, durability and appearance quality of the entire vehicle. With the development trend of lightweight and high-strength automobiles, traditional body stamping part forming methods face many challenges. During the stamping process, problems such as part deformation and springback caused by insufficient rigid support are prone to occur. Parts are damaged due to improper ejection timing and force during demolding. It is difficult to accurately control the degree of plastic deformation in the forming area, affecting the dimensional accuracy and surface quality of the parts. These problems not only reduce production efficiency, but also increase production costs. Therefore, a more scientific, efficient and precise body stamping part forming method is urgently needed to meet the increasingly stringent production needs.

[0003] For example, Chinese patent publication number: CN112338092A, which discloses a method for eliminating distortion in the overlap area of ​​the front bumper of a fender stamping, includes the application of a forming compensation process and the development of a debugging process. This method uses precision measuring equipment to confirm the amount of distortion and springback of the front bumper of the fender stamping; by supplementing the shaping process with fillet compensation, the principle of stable shaping of fillet plastic deformation is utilized to effectively correct the distortion and springback of the front bumper of the fender stamping; the standardizing of the contour grinding direction ensures the stability of the distortion and springback of the front bumper of the corrected fender stamping; and the rational use of multi-dimensional mounting point compensation means to achieve a comprehensive debugging method for eliminating the distortion and springback of the front bumper of the fender stamping.

[0004] The following problems also exist in the prior art:

[0005] The existing technology does not take into account the possible lack of coordination in the forming processes of different areas, resulting in local stress concentration. The existing technology cannot jointly analyze the forming process of the stamping edge and cannot scientifically optimize the ejection action of the ejector pin, which affects the production efficiency and product quality stability of the body stamping parts. Summary of the Invention

[0006] To this end, the present invention provides a vehicle body stamping part forming method based on combined stamping to overcome the problems in the prior art that the forming process of the stamping edge cannot be jointly analyzed and the ejection action of the ejector pin cannot be scientifically optimized.

[0007] To achieve the above-mentioned object, the present invention provides a method for forming a vehicle body stamping part based on combined stamping, comprising:

[0008] Obtain in advance the target contour of the part to be stamped and the position of the ejector pins set on the stamping die;

[0009] Comparing the target contour with the current contour of the part to be stamped to mark a number of stamping contact feature points on the part to be stamped, and screening rigid support risk points based on the distribution positions of the stamping contact feature points on the part to be stamped;

[0010] Determining the surface sub-contour corresponding to the rigid support risk point in the target contour, determining the forming characterization vector of the surface sub-contour that meets the spatial position association relationship, and determining the forming joint quantization area on the part to be stamped based on the comparison and analysis results of the forming characterization vector;

[0011] Pre-stamping the part to be stamped with a preset stamping stroke, and determining a forming collaborative characterization value based on a vector comparison result of a sub-region within the forming joint quantization region where the pre-stamping is completed, so as to determine whether to perform demolding and pre-ejection on the forming joint quantization region;

[0012] In response to the determination result of the pre-ejection of the molded joint quantization area, the pre-ejection ejector pin is determined based on the position relationship between the position of the ejector pin and the formed joint quantization area, and the ejection duration of the pre-ejection ejector pin for pre-ejecting the stamped part is adjusted.

[0013] Furthermore, the process of marking a plurality of stamping contact feature points on the surface of the workpiece to be stamped includes:

[0014] Obtaining coordinates of contour surface points of the target contour and the current contour of the part to be stamped in the same spatial coordinate system;

[0015] Determining the coordinate difference between the target contour and the contour surface point on the current contour of the part to be stamped along the stamping direction;

[0016] On the part to be stamped, the contour surface points whose coordinate difference exceeds a preset coordinate difference threshold are marked as stamping contact feature points.

[0017] Furthermore, the process of screening rigid support risk points includes:

[0018] Determining an edge area on the part to be stamped;

[0019] Screening the stamping contact feature points distributed in the edge area as rigid support risk points;

[0020] The edge area is determined based on the current contour of the part to be punched.

[0021] Furthermore, the process of determining the surface sub-contour corresponding to the rigid support risk point in the target contour includes:

[0022] Determining the corresponding point of the rigid support risk point in the target contour along the stamping direction;

[0023] The corresponding point is used as a central reference of the triangular area, and the triangular area is determined as the surface sub-contour.

[0024] Furthermore, the process of determining a plurality of surface sub-contours that conform to the spatial position correlation relationship includes:

[0025] Get the separation distance between any two surface sub-contours;

[0026] The plurality of surface sub-contours whose interval distances do not exceed a preset interval distance reference value are determined as surface sub-contours that conform to the spatial position association relationship.

[0027] Furthermore, the process of determining the forming joint quantization region according to the comparison analysis results of the forming characterization vectors includes:

[0028] Determine the contour plane of the surface sub-contour according to the coordinates of the triangle vertices on the surface sub-contour;

[0029] Determining the normal vector of the contour plane as a shaping characterization vector of the surface sub-contour;

[0030] Obtain the vector angle between any two forming representation vectors;

[0031] An area consisting of several surface sub-contours whose vector included angle does not exceed a preset included angle reference value is determined as the formed joint quantization area.

[0032] Furthermore, the process of determining the molding co-characterization quantity includes:

[0033] Dividing the forming joint quantization area where pre-punching is completed into a plurality of sub-areas;

[0034] Calculate the vector angle between the normal vectors of any two sub-regions and the standard deviation of the vector angle between the normal vectors;

[0035] The vector angle standard deviation is determined as the forming collaborative characterization quantity of the forming joint quantization area.

[0036] Furthermore, the process of determining whether to perform demoulding and pre-ejection on the molding combined quantization area includes:

[0037] Comparing the forming collaborative characterization value with a preset forming collaborative characterization value threshold;

[0038] If the molding collaborative characterization value exceeds the molding collaborative characterization value threshold, it is determined that the molding joint quantization area is to be demolded and pre-ejected.

[0039] Furthermore, the process of determining the pre-ejection ejector pin includes:

[0040] Obtaining the distance between the position of each ejector pin and the forming joint quantization area;

[0041] The ejector pin having the minimum distance from the forming joint quantization area is determined as the pre-ejector ejector pin.

[0042] Furthermore, the process of adjusting the duration of the pre-ejection ejection pin for pre-ejecting the stamped part includes:

[0043] Determining the ejection duration of the pre-ejection spring pin according to the molding collaborative characterization quantity;

[0044] The ejection duration is positively correlated with the molding coordination characteristic.

[0045] Compared with the prior art, the beneficial effect of the present invention lies in that the present invention obtains the target contour of the part to be stamped and the position of the ejector pin set on the stamping die in advance, marks a number of stamping contact feature points on the part to be stamped and screens the rigid support risk points, determines the surface sub-contour corresponding to the rigid support risk point in the target contour, determines the forming characterization vector of the surface sub-contour that conforms to the spatial position association relationship, determines the forming joint quantization area on the part to be stamped according to the comparison and analysis results of the forming characterization vector, determines the forming collaborative characterization quantity based on the vector comparison results of the sub-area in the said forming joint quantization area after the pre-stamping is completed, so as to determine whether to perform demolding and pre-ejection on the forming joint quantization area, and finally adjusts the ejection duration of the pre-ejection ejector pin for pre-ejection of the stamped part. The present invention realizes the joint analysis of the forming process of the stamping edge and scientifically optimizes the ejection action of the ejector pin, thereby realizing precise control and collaborative optimization of the stamping process.

[0046] Furthermore, the present invention places the target contour and the current contour in the same spatial coordinate system, calculates the coordinate difference of the corresponding surface points along the stamping direction, and essentially quantifies the expected deformation of the material at each point during the stamping process. These stamping contact feature points are marked, and in fact a mapping relationship between the material deformation and the mold action position is established, revealing the intrinsic connection between the material flow law and the forming defects.

[0047] Furthermore, the present invention determines the edge area based on the current contour and screens the stamping contact feature points therein. When the stamping contact feature points are concentrated there, it indicates that the area needs to withstand large local stress under the action of the mold, and its own rigidity is not enough to resist deformation, which can easily cause problems such as cracking, wrinkling or excessive rebound. This screening mechanism combines geometric feature analysis with deformation quantification to accurately locate potential rigidity weak areas, providing a direct basis for subsequent optimization of ejector pin layout and ejection strategy.

[0048] Furthermore, the present invention obtains the spacing distance between any two surface sub-contours and compares it with a preset reference value. When the spacing distance between the two surface sub-contours is small, it indicates that they are adjacent to each other in physical space, and collaborative deformation may occur due to the continuity of the material during the stamping process. The present invention realizes a joint analysis of the forming process of the stamping edge and predicts possible stress concentration areas in advance.

[0049] Furthermore, the present invention determines the contour plane by the coordinates of the triangle vertices on the surface sub-contour, and uses its normal vector as the forming characterization vector, converting complex three-dimensional geometric shapes into quantifiable and comparable vector information. Each forming characterization vector represents the material deformation trend of the corresponding area. Obtaining the angle between any two forming characterization vectors can accurately measure the relative orientation differences of different surface sub-contours in space, reflecting the degree of plastic deformation synergy within the region. When the vector angle does not exceed the preset reference value, it means that these surface sub-contours have similar spatial extension degrees, and the plastic deformation trends of the materials during the stamping process are similar, and they can achieve effective connection and cooperative deformation with each other. Through quantitative analysis of the forming characterization vectors, regions with similar extension and deformation characteristics are clearly defined.

[0050] Furthermore, the present invention determines the duration of ejection based on the forming coordination characterization quantity, and the two are positively correlated. This is because the forming coordination characterization quantity reflects the consistency of deformation and the degree of stress concentration within the forming joint quantification area. The larger the value, the greater the deformation difference within the area and the more unbalanced the stress. At this time, a longer ejection time is required to gradually balance the stress and eliminate the deformation difference. This ejector pin selection and ejection duration control strategy based on quantitative analysis realizes the refined management of the demolding process and effectively improves the demolding quality and production stability of the body stamping parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 This is a step diagram of a vehicle body stamping part forming method based on combined stamping according to an embodiment of the present invention;

[0052] Figure 2 A diagram showing the steps for marking several punching contact feature points according to an embodiment of the present invention;

[0053] Figure 3A diagram showing the steps for determining a forming joint quantization region according to an embodiment of the present invention;

[0054] Figure 4 This is a logic flow chart for determining whether to perform demoulding and pre-ejection on the molding joint quantization area according to an embodiment of the present invention. DETAILED DESCRIPTION

[0055] In order to make the objects and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are merely used to explain the present invention and are not intended to limit the present invention.

[0056] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0057] It should be noted that, in the description of the present invention, terms such as "upper", "lower", "inside" and "outside" indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings. This is only for the convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the present invention.

[0058] See also Figure 1 As shown in FIG, it is a step diagram of a vehicle body stamping part forming method based on combined stamping according to an embodiment of the present invention. The vehicle body stamping part forming method based on combined stamping according to the present invention comprises:

[0059] Step S100, pre-acquiring the target contour of the part to be stamped and the position of the ejector pins provided on the stamping die;

[0060] In the implementation of the present invention, the target contour of the part to be stamped can be obtained by scanning the stamped part using a laser scanning unit, and the target contour of the part to be stamped can be constructed based on the acquired point cloud data. This is a prior art and will not be described in detail here.

[0061] Those skilled in the art can understand that the ejector pin is a key component in the stamping die used to assist in the demolding of stamping parts. It is usually composed of a pin body, a spring, a guide sleeve and other parts. It is widely used in the demolding process of stamping forming and will not be described in detail here.

[0062] Step S200, comparing the target contour with the current contour of the part to be stamped to mark a number of stamping contact feature points on the part to be stamped, and screening rigid support risk points based on the distribution positions of the stamping contact feature points on the part to be stamped;

[0063] Step S300: determining a surface sub-contour corresponding to a rigid support risk point in the target contour, determining a forming characterization vector of the surface sub-contour that conforms to a spatial position association relationship, and determining a forming joint quantization area on the part to be stamped based on a comparison and analysis result of the forming characterization vector;

[0064] Step S400, pre-stamping the part to be stamped with a preset stamping stroke, and determining a forming collaborative characterization value based on a vector comparison result of a sub-region within the forming joint quantization region where the pre-stamping is completed, so as to determine whether to perform demolding and pre-ejection on the forming joint quantization region;

[0065] Step S500, in response to the determination result of the pre-ejection of the molded joint quantization area, the pre-ejection ejector pin is determined based on the position relationship between the position of the ejector pin and the position of the molded joint quantization area, and the ejection duration of the pre-ejection ejector pin for pre-ejecting the stamped part is adjusted.

[0066] In the implementation of the present invention, for the hydraulically driven ejector pin, the speed at which the hydraulic oil enters the ejector pin driving cylinder can be controlled by adjusting the opening size and flow rate of the hydraulic valve, thereby controlling the ejection and reset time of the ejector pin, and thus achieving control over the ejection duration. The ejection duration is the time it takes for the ejector pin to complete ejection and reset.

[0067] Specifically, see Figure 2 As shown, it is a step diagram of marking a plurality of stamping contact feature points according to an embodiment of the present invention. The process of marking a plurality of stamping contact feature points on the surface of the workpiece to be stamped includes:

[0068] Step S211, obtaining the coordinates of the contour surface points of the target contour and the current contour of the part to be stamped in the same spatial coordinate system;

[0069] Step S212, determining the coordinate difference between the target contour and the contour surface point on the current contour of the part to be stamped along the stamping direction;

[0070] Step S213 , marking the contour surface points on the workpiece to be stamped whose coordinate difference exceeds a preset coordinate difference threshold as stamping contact feature points.

[0071] In the implementation of the present invention, a spatial coordinate system is constructed with the Z-axis along the stamping direction and any point on the surface of the part to be stamped as the origin, wherein the stamping direction is the direction in which the movable mold of the stamping mold is closed toward the fixed mold. The value of the preset coordinate difference threshold can be obtained based on pre-calculation, and the average coordinate difference between the target contour and the contour surface points on the current contour of the part to be stamped is pre-calculated. The coordinate difference threshold = the average coordinate difference value × the coordinate difference threshold value factor. The value range of the coordinate difference threshold value factor is [1.1, 1.2]. For example, the value of the coordinate difference threshold value factor is 1.15 to ensure that the material at the marked stamping contact feature point undergoes greater extension or compression.

[0072] Specifically, the present invention obtains the surface point coordinates of the target contour and the current contour in the same coordinate system, calculates the coordinate difference along the stamping direction, and marks the points exceeding the threshold as stamping contact feature points, thereby quantitatively evaluating the degree of material extension of the target shape compared to the part to be stamped. During the car body stamping process, the plastic deformation and flow characteristics of the material determine the molding quality of the final part. By placing the target contour and the current contour in the same spatial coordinate system, the coordinate difference of the corresponding surface points is calculated along the stamping direction. In essence, the expected deformation of the material at each point in the stamping process is quantified. When the coordinate difference of a certain point exceeds the preset threshold, it indicates that the material at this position needs to undergo a large extension or compression to achieve the target shape. These points usually correspond to the initial contact points between the mold and the material, stress concentration areas or complex curved surface transition areas. Marking these stamping contact feature points actually establishes a mapping relationship between the material deformation and the mold action position.

[0073] Specifically, the process of screening rigid support risk points includes:

[0074] Determining an edge area on the part to be stamped;

[0075] Screening the stamping contact feature points distributed in the edge area as rigid support risk points;

[0076] The edge area is determined based on the current contour of the part to be punched.

[0077] Exemplarily, the edge line of the current contour of the part to be stamped in the stamping direction dimension is determined in advance, the point cloud data or geometric model of the contour is obtained using 3D modeling software or scanning equipment, the edge line of the current contour is identified and extracted through an edge detection algorithm, the edge line of the current contour is proportionally reduced, and the proportional reduction of the edge line is achieved by setting a scaling factor, and the closed area constructed by the reduced edge line and the edge line of the current contour is determined as the edge area, wherein the scaling factor can take a value of 0.85.

[0078] It is understandable that in the stamping process of the car body, the edge area of ​​the part to be stamped is prone to forming defects due to insufficient rigid support due to its special geometric characteristics and stress state. By determining the edge area based on the current contour and screening the stamping contact feature points therein, when the stamping contact feature points are concentrated here, it indicates that the area needs to withstand large local stress under the action of the mold, and its own rigidity is not enough to resist deformation, which can easily cause cracking, wrinkling or excessive rebound. This screening mechanism combines geometric feature analysis with deformation quantification to accurately locate potential weak rigidity areas, providing a direct basis for subsequent optimization of ejector pin layout and ejection strategy.

[0079] Specifically, the process of determining the surface sub-contour corresponding to the rigid support risk point in the target contour includes:

[0080] Determining the corresponding point of the rigid support risk point in the target contour along the stamping direction;

[0081] The corresponding point is used as a central reference of the triangular area, and the triangular area is determined as the surface sub-contour.

[0082] Exemplarily, the triangular size of the surface sub-contour can be set by a person skilled in the art. The size of the triangular surface sub-contour needs to ensure that the surface sub-contour can characterize the material deformation characteristics of the local area. Preferably, in the implementation of the present invention, the surface sub-contour can be determined as an equilateral triangle with a side length of 10 cm.

[0083] It can be understood that by mapping the risk points on the part to be stamped to the corresponding points on the target contour along the stamping direction, and constructing a triangular area with the point as the center as the surface sub-contour, the complex three-dimensional surface can be converted into a planar unit with a clear mathematical expression, and the unique plane is determined according to the coordinates of the three vertices of the triangle, which facilitates the determination of the normal vector of the unique plane.

[0084] Specifically, the process of determining a plurality of surface sub-contours that conform to the spatial position correlation relationship includes:

[0085] Get the separation distance between any two surface sub-contours;

[0086] The plurality of surface sub-contours whose interval distances do not exceed a preset interval distance reference value are determined as surface sub-contours that conform to the spatial position association relationship.

[0087] In the implementation of the present invention, the spacing distance between two surface sub-contours can be the spacing distance between the center references of the two surface sub-contours. The preset spacing distance reference value is determined according to the size of the part to be stamped. Here, a method for taking the spacing distance reference value is provided. The spacing distance reference value = the maximum length of the part to be stamped × the spacing distance reference value factor. The spacing distance reference value factor has a value range of [0.15, 0.2]. The preferred value of the spacing distance reference value factor is 0.18 to ensure that the surface sub-contours screened out that meet the spatial position correlation relationship produce cooperative deformation through the continuity of the material during the stamping process.

[0088] It is understandable that during the body stamping process, the spatial correlation between adjacent surface sub-contours significantly influences material flow and stress distribution. By obtaining the separation distance between any two surface sub-contours and comparing it with a preset reference value, a smaller separation distance indicates that they are physically adjacent to each other. During the stamping process, synergistic deformation may occur due to material continuity, forming a localized stress transfer path. However, if the separation distance exceeds a threshold, the material deformation between the two is highly independent, making effective synergy difficult to achieve. This screening mechanism quantifies the degree of spatial coupling between sub-contours, correlating discrete geometric units into physically meaningful forming regions.

[0089] Specifically, see Figure 3 As shown in FIG. , which is a step diagram for determining a forming joint quantization region according to an embodiment of the present invention, the process of determining a forming joint quantization region according to the comparison and analysis results of the forming characterization vectors includes:

[0090] Step S311, determining the contour plane of the surface sub-contour according to the coordinates of the triangle vertices on the surface sub-contour;

[0091] Step S312, determining the normal vector of the contour plane as the shaping characterization vector of the surface sub-contour;

[0092] Step S313, obtaining the vector angle between any two forming characterization vectors;

[0093] Step S314 : determining a region consisting of several surface sub-contours whose vector angles do not exceed a preset angle reference value as the formed joint quantization region.

[0094] In the implementation of the present invention, determining the contour plane and the normal vector of the contour plane based on three known coordinate points is an existing technology and will not be repeated here. The angle between the two vectors can also be calculated by three-dimensional simulation software; the preset angle reference value can be in the range of [12°, 15°]. Preferably, the angle reference value can be 13° to ensure that the surface sub-contours within the forming joint quantization area have similar spatial extension degrees.

[0095] It is understandable that during the forming process of vehicle body stamping parts, the direction and degree of plastic deformation of materials in different areas will directly affect the overall forming quality. By determining the contour plane with the coordinates of the triangle vertices on the surface sub-contour and using its normal vector as the forming characterization vector, the complex three-dimensional geometric shape is converted into quantifiable and comparable vector information. Each forming characterization vector represents the material deformation trend of the corresponding area. Obtaining the angle between any two forming characterization vectors can accurately measure the relative orientation differences of different surface sub-contours in space, reflecting the degree of plastic deformation synergy within the region. When the vector angle does not exceed the preset reference value, it means that these surface sub-contours have similar spatial extension, and the plastic deformation trends of the materials during the stamping process are similar. They can achieve effective connection and cooperative deformation with each other. Through quantitative analysis of the forming characterization vectors, regions with similar extension and deformation characteristics are clearly defined.

[0096] Specifically, the process of determining the molding co-characterization quantity includes:

[0097] Dividing the forming joint quantization area where pre-punching is completed into a plurality of sub-areas;

[0098] Calculate the vector angle between the normal vectors of any two sub-regions and the standard deviation of the vector angle between the normal vectors;

[0099] The vector angle standard deviation is determined as the forming collaborative characterization quantity of the forming joint quantization area.

[0100] In the implementation of the present invention, the pre-stamped forming joint quantization area can be divided into several equilateral triangle sub-areas to facilitate determination of the normal vector of the area. The side length of the equilateral triangle sub-area can be 0.5 times the side length of the surface sub-contour.

[0101] It can be understood that by dividing the pre-stamping forming joint quantification area into several sub-areas, using the sub-area normal vector to characterize the local deformation direction, calculating the angle between the normal vectors of any two sub-areas and the standard deviation of the angle, the degree of discreteness of the deformation direction in the area is quantified using statistical methods. The normal vector angle reflects the difference in deformation direction between sub-areas, while the standard deviation of the angle measures the consistency of the deformation direction in the entire forming joint quantification area. The smaller the standard deviation, the more consistent the deformation directions of the sub-areas and the better the forming synergy; conversely, the larger the standard deviation, the more chaotic the deformation directions in the area, which can easily lead to problems such as stress concentration and uneven material flow. Using the standard deviation as a characterization of forming synergy can transform complex deformation synergy characteristics into a single quantitative indicator.

[0102] Specifically, see Figure 4As shown, it is a logic flow chart for determining whether to perform demolding and pre-ejection on the forming joint quantization area according to an embodiment of the present invention. The process of determining whether to perform demolding and pre-ejection on the forming joint quantization area includes:

[0103] Comparing the forming collaborative characterization value with a preset forming collaborative characterization value threshold;

[0104] If the molding collaborative characterization value exceeds the molding collaborative characterization value threshold, determining to perform demoulding pre-ejection on the molding joint quantization area;

[0105] If the molding collaborative characterization value does not exceed the molding collaborative characterization value threshold, it is determined that the molding joint quantization area is not to be demolded and pre-ejected.

[0106] In practice, the demolding pre-ejection is carried out by the ejector pin and maintains the ejection state. If the ejector pin is hydraulically driven, the hydraulic control system will adjust the hydraulic valve to allow the hydraulic oil to flow into the driving cylinder of the ejector pin to push the ejector pin out. This process effectively releases the internal stress of the stamping part by precisely controlling the duration of the ejection pin.

[0107] In the implementation of the present invention, the value of the preset molding collaborative characterization threshold can be set by those skilled in the art according to the accuracy of detection and identification. In order to ensure that there are obvious differences in the coordination of the deformation of each part in the molding joint quantization area that requires demolding and pre-ejection, the value range of the molding collaborative characterization threshold is [3°, 5°]. Preferably, the value of the molding collaborative characterization threshold is set to 4°.

[0108] It is understandable that the forming collaborative characterization quantity reflects the consistency and coordination of the deformation of each part in the forming joint quantification area. When the value exceeds the preset threshold, it means that the deformation difference in the area is too large, and there is local stress concentration or uneven material flow. If the stamping part is directly demolded at this time, it is very easy to have defects such as warping and cracking due to internal stress imbalance. The forming collaborative characterization quantity is compared with the threshold. According to the relationship between stress and deformation in material mechanics, the quantitative indicators are used to judge whether the internal stress state of the stamping part is suitable for demolding. When the threshold is exceeded, it is determined to perform pre-ejection of the demolding. The ejector pin is used to apply a certain ejection force to the stamping part in advance, which can gradually release the internal stress, balance the force of each part, reduce the risk of forming defects caused by stress mutation, and ensure the integrity and quality stability of the stamping part during the demolding process, thereby achieving refined control of the forming process of the body stamping part.

[0109] Specifically, the process of determining the pre-ejection ejector pin includes:

[0110] Obtaining the distance between the position of each ejector pin and the forming joint quantization area;

[0111] The ejector pin having the minimum distance from the forming joint quantization area is determined as the pre-ejector ejector pin.

[0112] In the implementation of the present invention, the distance between the position of the ejector pin and the forming joint quantization area can be the projection distance between the position of the ejector pin and any point on the edge of the forming joint quantization area on the surface perpendicular to the stamping direction. The calculation of the projection distance is an existing technology and will not be repeated here.

[0113] Specifically, the process of adjusting the ejection duration of the pre-ejection pin for pre-ejecting the stamped part includes:

[0114] Determining the ejection duration of the pre-ejection spring pin according to the molding collaborative characterization quantity;

[0115] The ejection duration is positively correlated with the molding coordination characteristic.

[0116] In the implementation of the present invention, the ejection duration of the ejector pin = (molding synergy characterization quantity / molding synergy characterization quantity threshold) × the initial value of the ejection duration. That is, the larger the molding synergy characterization quantity, the larger the dimensionless ratio of the molding synergy characterization quantity to the molding synergy characterization quantity threshold, and the larger the final ejection duration of the ejector pin relative to the initial value of the ejection duration. The initial value of the ejection duration is a value set by those skilled in the art for the ejection duration of the ejector pin based on the minimum molding synergy characterization quantity. A preferred value of the initial value of the ejection duration is 0.8s.

[0117] It is understandable that in the demolding process of body stamping parts, the rational selection of ejector pins and the precise control of ejection duration are extremely critical. According to the principle of proximity, the ejection force can be quickly and effectively transmitted to the stress concentration or complex deformation area, so as to release the internal stress of the stamping part more efficiently. The ejection duration is determined according to the forming coordination characterization quantity, and the two are positively correlated. This is because the forming coordination characterization quantity reflects the consistency of deformation and the degree of stress concentration within the forming joint quantitative area. The larger the value, the greater the deformation difference and the more unbalanced the stress in the area. At this time, a longer ejection effect is required to gradually balance the stress and eliminate the deformation difference. This quantitative analysis-based ejector pin selection and ejection duration control strategy realizes the refined management of the demolding process and effectively improves the demolding quality and production stability of body stamping parts.

[0118] An embodiment of the present invention also provides a computer-readable storage medium, which stores computer program code. When the computer program code is run on a computer, the computer executes the above-mentioned related method steps to implement the body stamping parts forming method based on combined stamping provided in the above embodiment.

[0119] Thus far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art may make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will fall within the scope of protection of the present invention.

[0120] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that the present invention is susceptible to various modifications and variations. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A method for forming vehicle body stamping parts based on combined stamping, characterized in that: include: Obtain in advance the target contour of the part to be stamped and the position of the ejector pins set on the stamping die; Comparing the target contour with the current contour of the part to be stamped to mark a number of stamping contact feature points on the part to be stamped, and screening rigid support risk points based on the distribution positions of the stamping contact feature points on the part to be stamped; Determining the surface sub-contour corresponding to the rigid support risk point in the target contour, determining the forming characterization vector of the surface sub-contour that meets the spatial position association relationship, and determining the forming joint quantization area on the part to be stamped based on the comparison and analysis results of the forming characterization vector; Pre-stamping the part to be stamped with a preset stamping stroke, and determining a forming collaborative characterization value based on a vector comparison result of a sub-region within the forming joint quantization region where the pre-stamping is completed, so as to determine whether to perform demolding and pre-ejection on the forming joint quantization region; In response to the determination result of the pre-ejection of the molded joint quantization area, the pre-ejection ejector pin is determined based on the position relationship between the position of the ejector pin and the formed joint quantization area, and the ejection duration of the pre-ejection ejector pin for pre-ejecting the stamped part is adjusted.

2. The method for forming vehicle body stamping parts based on combined stamping according to claim 1, characterized in that: The process of marking a plurality of stamping contact feature points on the surface of the workpiece to be stamped includes: Obtaining coordinates of contour surface points of the target contour and the current contour of the part to be stamped in the same spatial coordinate system; Determining the coordinate difference between the target contour and the contour surface point on the current contour of the part to be stamped along the stamping direction; On the part to be stamped, the contour surface points whose coordinate difference exceeds a preset coordinate difference threshold are marked as stamping contact feature points.

3. The method for forming vehicle body stamping parts based on combined stamping according to claim 2, characterized in that: The process of screening rigid support risk points includes: Determining an edge area on the part to be stamped; Screening the stamping contact feature points distributed in the edge area as rigid support risk points; The edge area is determined based on the current contour of the part to be punched.

4. The method for forming vehicle body stamping parts based on combined stamping according to claim 3, characterized in that: The process of determining the surface sub-contour corresponding to the rigid support risk point in the target contour includes: Determining the corresponding point of the rigid support risk point in the target contour along the stamping direction; The corresponding point is used as a central reference of the triangular area, and the triangular area is determined as the surface sub-contour.

5. The method for forming vehicle body stamping parts based on combined stamping according to claim 4, characterized in that: The process of determining a plurality of surface sub-contours that conform to the spatial position correlation relationship includes: Get the separation distance between any two surface sub-contours; The plurality of surface sub-contours whose interval distances do not exceed a preset interval distance reference value are determined as surface sub-contours that conform to the spatial position association relationship.

6. The method for forming vehicle body stamping parts based on combined stamping according to claim 5, characterized in that: The process of determining the forming joint quantization area based on the comparison analysis results of the forming characterization vectors includes: Determine the contour plane of the surface sub-contour according to the coordinates of the triangle vertices on the surface sub-contour; Determining the normal vector of the contour plane as a shaping characterization vector of the surface sub-contour; Obtain the vector angle between any two forming representation vectors; An area consisting of several surface sub-contours whose vector included angle does not exceed a preset included angle reference value is determined as the formed joint quantization area.

7. The method for forming vehicle body stamping parts based on combined stamping according to claim 6, characterized in that: The process of determining the molding co-characterization quantity includes: Dividing the forming joint quantization area where pre-punching is completed into a plurality of sub-areas; Calculate the vector angle between the normal vectors of any two sub-regions and the standard deviation of the vector angle between the normal vectors; The vector angle standard deviation is determined as the forming collaborative characterization quantity of the forming joint quantization area.

8. The method for forming vehicle body stamping parts based on combined stamping according to claim 7, characterized in that: The process of determining whether to perform demolding and pre-ejection on the molding joint quantization area includes: Comparing the forming collaborative characterization value with a preset forming collaborative characterization value threshold; If the molding collaborative characterization value exceeds the molding collaborative characterization value threshold, it is determined that the molding joint quantization area is to be demolded and pre-ejected.

9. The method for forming vehicle body stamping parts based on combined stamping according to claim 8, characterized in that: The process for determining the pre-ejector pins includes: Obtaining the distance between the position of each ejector pin and the forming joint quantization area; The ejector pin having the minimum distance from the forming joint quantization area is determined as the pre-ejector ejector pin.

10. The method for forming vehicle body stamping parts based on combined stamping according to claim 9, characterized in that: The process of adjusting the ejection duration of the pre-ejection pin for pre-ejecting the stamped part includes: Determining the ejection duration of the pre-ejection spring pin according to the molding collaborative characterization quantity; The ejection duration is positively correlated with the molding coordination characteristic.

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