A method for inspecting the pressed edges of sheet metal products

Abstract

This invention provides a method for inspecting the pressed edges of sheet metal products. Based on the entry and exit function interfaces provided by 3D design software, as well as user-developed functions, the method involves the following steps: opening the sheet metal digital model in the 3D design software, starting the sheet metal pressed edge inspection, data acquisition, determining whether the pressed edges meet processing requirements based on materials and processing methods, determining whether the pressed edges meet processing requirements based on sheet metal pressed edge data, automatically analyzing the sheet metal pressed edges in the 3D design software, and calculating the pressed edge length. This eliminates the need for manual model analysis, saves labor costs, solves the problem of sheet metal pressed edge inspection, avoids processing problems that may be encountered during part production, and can further encourage design engineers to design products that meet processing requirements, thereby improving the design quality of engineers.

Description

Technical Field

[0001] This invention relates to the field of computer calculation and calibration, and in particular to a method for inspecting the pressed edges of sheet metal products. Background Technology

[0002] In the process of sheet metal product design and manufacturing, according to the sheet metal product design specifications, the pressed edge of sheet metal products refers to the process of bending the sheet metal workpiece into an acute angle of 30-35°, and then using a flattening mold to flatten and press the workpiece, so that it looks like a double-layer shape. Pressing the edge is a very common operation, also known as reverse folding and flattening or sheet metal folding.

[0003] When engineers design parts or modify products according to product requirements, they may not allow enough for the crimped edge length, or the material may not be suitable for crimping. This can lead to insufficient strength at the sheet metal edge, resulting in a rough edge with burrs after circumferential finishing, requiring grinding. This compromises the quality of the machined dimensions and parts. Currently, the length of the crimped edge is determined manually, as are the judgments regarding part materials and lengths. Engineers may not proactively check whether the crimped edge length conforms to design specifications, potentially leading to design errors. This can result in sheet metal products with unprocessable crimped edges, sharp or uneven edges, and production anomalies due to product designers' unfamiliarity with sheet metal design specifications. Furthermore, if designers are not familiar with sheet metal product design specifications, this can cause production abnormalities, requiring design rework and consuming significant production time, thus impacting product production schedules. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by proposing a method for inspecting the pressed edges of sheet metal products.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A method for inspecting pressed edges of sheet metal products, based on 3D design software, the 3D design software including an entry function interface and an exit function interface, and also including a sheet metal pressed edge inspection function;

[0007] The 3D design software is an application used to create and edit 3D models, including SolidWorks, Creo, and WIT 3D;

[0008] The entry function interface and the exit function interface are development interfaces provided by the 3D design software, used to interface with functions developed and written by the user.

[0009] The sheet metal dead edge check function is a user-defined, unique function used to perform sheet metal dead edge checks.

[0010] Specifically, the following steps are included:

[0011] S1: Open the sheet metal digital model in the 3D design software;

[0012] The sheet metal digital model is a digital model of the product designed by the engineer. The sheet metal digital model includes a solid model and a sheet metal model. The sheet metal model has the characteristic that the thickness of the same part is consistent.

[0013] S2: Begin performing sheet metal edge pressing inspection:

[0014] The sheet metal dead edge inspection function is linked to the sheet metal dead edge inspection function through the 3D design software's entry and exit functions.

[0015] Sheet metal pressed edges refer to the edges of sheet metal in the form of folded edges; sheet metal pressed edges inspection refers to checking whether the design of the current sheet metal model conforms to the pressed edges design standard.

[0016] The process of performing sheet metal edge pressing inspection includes: obtaining the material of the model and the surface treatment method of the model; traversing the faces of the sheet metal model and the edges of the sheet metal faces, obtaining the edge data, finding the pressing edges through the algorithm, calculating the minimum length of the pressing edges, and determining whether the minimum length of the pressing edges meets the requirements.

[0017] S3: Data Acquisition: Includes acquiring sheet metal material and processing data, basic data of sheet metal edges, and data of sheet metal pressed edges.

[0018] The sheet metal pressed edge data includes the sheet metal pressed edge length, gap, and corner radius; the sheet metal edge basic data includes sheet metal thickness, endpoints of straight edges, center point of arc edges, start point, end point, and arc radius.

[0019] S4: Determine whether the pressed edge meets the processing requirements based on the material and processing method:

[0020] The sheet metal materials and processing data are judged. If the sheet metal materials and processing data meet the requirements, proceed to the next step; otherwise, the pressed edge design cannot be performed.

[0021] S5: Determine whether the pressed edge meets the processing requirements based on the sheet metal pressed edge data:

[0022] The sheet metal edge pressing data is checked using the sheet metal edge pressing check function: Let the minimum length of the edge pressing be L and the sheet metal thickness be t. The edge pressing must satisfy the formula L≥5*t. Edge pressing can be designed if it meets the calculation result of the sheet metal edge pressing check function. If it does not meet the calculation result of the sheet metal edge pressing check function, edge pressing cannot be designed.

[0023] Furthermore, in S4, the material and processing method are used to determine whether the pressed edge meets the processing requirements. If the sheet metal material and processing data inspection result is cold-galvanized sheet or the surface treatment method is electroplating, the pressed edge design cannot be performed.

[0024] Furthermore, step S3, obtaining the sheet metal pressed dead edge data, includes the following sub-steps:

[0025] S31: Traverse all solid faces of the sheet metal model using the API provided by the 3D design software to obtain the unique identifier ID of the solid face and get the thickness t of the sheet metal;

[0026] The API stands for Application Programming Interface, which is a convention for connecting different components of a software system.

[0027] The unique identifier ID of the solid surface refers to the ID number corresponding to each solid surface, and the unique identifier ID of the solid surface is unique in the current sheet metal model;

[0028] S32: Use the API provided by the 3D design software to cycle through all solid surfaces of the sheet metal model and obtain the type of solid surface, which includes planar and cylindrical surfaces;

[0029] Collect the cylindrical surfaces and obtain their surface properties through the API provided by the 3D design software. The surface properties include sheet metal surfaces and sheet metal side surfaces.

[0030] S33: Obtain all solid edges through the API provided by the 3D design software, obtain the unique identifier ID of the solid edge, and obtain the type of the solid edge. The types of solid edges include straight edges and curved edges.

[0031] The unique identifier ID of the entity edge refers to the ID number corresponding to each entity edge, and the unique identifier ID of the entity edge is unique in the current sheet metal model;

[0032] Edge attributes can be obtained through the API provided by the 3D design software. Edge attributes include straight edges, which provide the coordinates of the two endpoints; and arc edges, which provide the coordinates of the arc's center point, starting point, ending point, and midpoint.

[0033] S34: Using the API provided by the 3D design software, cycle through cylindrical surfaces, and filter and determine sheet metal surfaces based on surface type:

[0034] Traverse the cylindrical surface to obtain two straight edges and two circular arc edges. Let the center coordinates of one arc be P(XP,YP,ZP), the starting point of the arc be E1(X1,Y1,Z1), the ending point be E2(X2,Y2,Z2), and the midpoint of the arc be M(XP,YP,Z2). M Y M Z M Connect E1 and P to obtain line segment E1P, and connect E2 and P to obtain line segment E2P. According to the vector formula:

[0035] , ,

[0036] Let the angle between the vectors be θ. The formula for calculating the angle between vectors is the cosine vector angle formula.

[0037] ,

[0038] Solution:

[0039] ,

[0040] Once the included angle θ is obtained, similarly, the included angle from the other end point of the cylindrical surface to the center of the circle is calculated. When the included angle of both arcs is 180 degrees, the selected edge is determined to be a pressed edge.

[0041] S35: Connect the midpoint of the arc to the center of the circle to obtain line segment MP. Use the API provided by the 3D design software to obtain the adjacent faces of the sheet metal surface. Loop through the adjacent faces, traversing their edges. Use the API provided by the 3D design software to obtain the endpoints of the edges, collecting the endpoints into a set. Loop through the point set. According to the formula for projecting a point onto a line, let the endpoint of the adjacent face's edge be point A, and let the perpendicular point from point A to line segment MP be C(Xc, Yc, Zc). First, calculate the vector:

[0042] ,

[0043] ,

[0044] ,

[0045] Based on the perpendicular relationship of vectors; Formula 1 is obtained as follows:

[0046] Point C lies on line segment MP. According to the collinearity of vectors... and Collinearity yields Formula 2

[0047] ,

[0048] Formula 3 is derived from Formula 2.

[0049] ,

[0050] Substituting Formula 3 into Formula 1, we can calculate k and obtain Formula 4:

[0051] ,

[0052] Finally, substituting k into formula 3, we obtain the perpendicular point C. Using the distance formula, we determine the distance d from the center point P to the perpendicular point C:

[0053] ,

[0054] Similarly, the distances from all endpoints on adjacent surfaces to the center of the circle can be obtained. The maximum distance of an adjacent surface is found by looping through the surface. Let the maximum distance be dmax1. According to the above method, another adjacent surface of the cylinder is found. At the same time, the projection of the points on the adjacent surface onto the PM line segment is calculated. Then the distance from the projection point to the center of the circle is calculated. The maximum distance is found by looping through the surface. Let the maximum distance be dmax2.

[0055] Furthermore, in step S5, if the maximum distances dmax1 and dmax2 simultaneously satisfy dmax1≥5*t and dmax2≥5*t, where t is the thickness of the sheet metal, then the pressed edge meets the sheet metal design specifications.

[0056] Compared with existing technologies, the advantages of this invention are: it simplifies the engineer's operation, automatically analyzes the sheet metal pressed edges and calculates the pressed edge length on 3D design software, eliminating the need for manual model analysis; a single drawing can be reviewed in seconds to determine if the pressed edges meet the requirements. This solves the problem of sheet metal pressed edge inspection, avoids potential processing issues during parts production, allows design engineers to design products that meet processing requirements, and improves the quality of the engineer's designs. Attached Figure Description

[0057] Figure 1 This is a schematic diagram of the overall process of Embodiment 1 of the present invention;

[0058] Figure 2 This is a schematic diagram of the sheet metal side and sheet metal surface of Embodiment 1 of the present invention;

[0059] Figure 3 This is a schematic diagram of the dead edge determination in Embodiment 1 of the present invention;

[0060] Figure 4 This is a schematic diagram of the pressed edge points of the sheet metal surface in Embodiment 1 of the present invention. Detailed Implementation

[0061] To provide a better understanding of the purpose, structure, features, and functions of the present invention, detailed descriptions are provided below with reference to specific embodiments.

[0062] Example 1: As Figure 1 As shown:

[0063] A method for inspecting pressed edges of sheet metal products, based on 3D design software, which includes an entry function interface and an exit function interface, as well as a sheet metal pressed edge inspection function.

[0064] 3D design software is an application used to create and edit 3D models. Generally, any 3D design software with both input and output function interfaces is applicable, such as SolidWorks, Creo, and WIT 3D.

[0065] The entry function interface and the exit function interface are development interfaces provided by 3D design software, used to interface with functions developed and written by users.

[0066] The sheet metal dead edge check function is a user-defined function used to perform sheet metal dead edge checks.

[0067] By using custom functions, which are integrated into 3D design software via entry and exit function interfaces, the operation for engineers is simplified. The software automatically analyzes the dead edges of sheet metal and calculates their length, eliminating the need for manual model analysis and saving labor costs.

[0068] Specifically, the following steps are included:

[0069] S1: Open the sheet metal digital model in the 3D design software;

[0070] A sheet metal digital model is a digital model of a product designed by engineers. A sheet metal digital model includes a solid model and a sheet metal model. Sheet metal models have the characteristic that the thickness of the same part is consistent.

[0071] The digital model here is a designer's design model, which is based on design concepts and may not necessarily meet production requirements.

[0072] S2: Begin performing sheet metal edge pressing inspection:

[0073] The sheet metal dead edge inspection function is linked to the sheet metal dead edge inspection function through the 3D design software's entry and exit functions.

[0074] Sheet metal pressed edges refer to the edges of sheet metal in the form of folded edges; sheet metal pressed edges inspection refers to checking whether the design of the current sheet metal model conforms to the pressed edges design standard.

[0075] The process of performing sheet metal edge pressing inspection includes: obtaining the material of the model and the surface treatment method of the model; traversing the faces of the sheet metal model and the edges of the sheet metal faces to obtain the edge data; using an algorithm to find the pressing edges; calculating the minimum length of the pressing edges; and determining whether the minimum length of the pressing edges meets the requirements.

[0076] S3: Data Acquisition: Includes acquiring sheet metal material and processing data, basic data of sheet metal edges, and data of sheet metal pressed edges.

[0077] Sheet metal edge data, including edge length, gap, and fillet size; basic edge data, including sheet metal thickness, endpoints of straight edges, center point of curved edges, start point, end point, and radius of curvature.

[0078] Furthermore, step S3, obtaining the sheet metal pressed dead edge data, includes the following sub-steps:

[0079] S31: Traverse all solid faces of the sheet metal model using the API provided by the 3D design software to obtain the unique identifier ID of the solid face and get the thickness t of the sheet metal;

[0080] API stands for Application Programming Interface, which is a set of conventions for the connection between different components of a software system.

[0081] The unique identifier ID of a solid surface refers to the ID number corresponding to each solid surface. The unique identifier ID of a solid surface is unique in the current sheet metal model.

[0082] S32: Use the API provided by the 3D design software to cycle through all solid surfaces of the sheet metal model and obtain the type of solid surface, which includes planar and cylindrical surfaces;

[0083] The collected cylindrical surfaces are used to obtain surface attributes, including sheet metal surfaces and sheet metal side surfaces, through the API provided by the 3D design software. Figure 2 The diagram shows the side and surface of the sheet metal.

[0084] S33: Obtain all solid edges through the API provided by the 3D design software, obtain the unique identifier ID of the solid edge, and obtain the type of the solid edge. The types of solid edges include straight edges and curved edges.

[0085] The unique identifier ID of a solid edge refers to the ID number corresponding to each solid edge. The unique identifier ID of a solid edge is unique in the current sheet metal model.

[0086] Edge attributes can be obtained through the API provided by the 3D design software. Edge attributes include straight edges, which yield the coordinates of the two endpoints; and arc edges, which yield the coordinates of the arc's center point, starting point, ending point, and midpoint.

[0087] S34: Using the API provided by the 3D design software, cycle through cylindrical surfaces, and filter and determine sheet metal surfaces based on surface type:

[0088] Traverse the cylindrical surface to obtain two straight edges and two circular arc edges. Let the center coordinates of one arc be P(XP,YP,ZP), the starting point of the arc be E1(X1,Y1,Z1), the ending point be E2(X2,Y2,Z2), and the midpoint of the arc be M(XP,YP,Z2). M Y M Z M Connect E1 and P to obtain line segment E1P, and connect E2 and P to obtain line segment E2P. According to the vector formula:

[0089] , ,

[0090] Let the angle between the vectors be θ. The formula for calculating the angle between vectors is the cosine vector angle formula.

[0091] ,

[0092] Solution:

[0093] ,

[0094] Once the included angle θ is obtained, similarly, calculate the angle between the endpoint of the other arc on the cylindrical surface and the center. When the included angle of both arcs is 180 degrees, the selected edge is determined to be a pressed edge. Figure 3 As shown.

[0095] By using the API provided by the 3D design software to traverse the faces and edges of the sheet metal product, each face has a unique identifier ID, and each edge has a unique identifier ID. Then, the coordinates of the points are obtained. This operation method divides the sheet metal product into different areas and judges each edge of the solid based on the ID number, so as to make accurate judgments.

[0096] First, determine whether the included angle between two arcs is 180 degrees, and then determine whether the edge is a pressed edge. If it is determined to be a pressed edge, further determine whether the design of the pressed edge meets the processing requirements.

[0097] S35: Connect the midpoint of the arc to the center of the circle to obtain line segment MP. Use the API provided by the 3D design software to obtain adjacent faces of the sheet metal surface. Loop through the adjacent faces, traversing their edges. Use the API provided by the 3D design software to obtain the endpoints of the edges, collecting the endpoints into a set. Loop through the point set. According to the formula for projecting a point onto a line, let the endpoint of the adjacent face's edge be point A. Figure 4 As shown, let C(Xc, Yc, Zc) be the foot of the perpendicular from point A to line segment MP. First, calculate the vector:

[0098] ,

[0099] ,

[0100] ,

[0101] Based on the perpendicular relationship of vectors; Formula 1 is obtained as follows:

[0102]

[0103] Point C lies on line segment MP. According to the collinearity of vectors... and Collinearity yields Formula 2

[0104] ,

[0105] Formula 3 is derived from Formula 2.

[0106] ,

[0107] Substituting Formula 3 into Formula 1, we can calculate k and obtain Formula 4:

[0108] ,

[0109] Finally, substituting k into formula 3, we obtain the perpendicular point C. Using the distance formula, we determine the distance d from the center point P to the perpendicular point C:

[0110] ,

[0111] Similarly, the distances from all endpoints on adjacent surfaces to the center of the circle can be obtained. The maximum distance of an adjacent surface is found by looping through the surface. Let the maximum distance be dmax1. According to the above method, another adjacent surface of the cylinder is found. At the same time, the projection of the points on the adjacent surface onto the PM line segment is calculated. Then the distance from the projection point to the center of the circle is calculated. The maximum distance is found by looping through the surface. Let the maximum distance be dmax2.

[0112] The distance from the projection point to the center of the circle is found in two loops. The maximum distance is found in the loop, which is the maximum distance between the two sides of a dead edge. Here, the maximum dmax1 and dmax2 are found respectively. This can be used to exclude the fact that the standardization of the designer's design model itself does not meet the requirements of the processing standard. If only one side meets the dead edge standard, the dead edge still does not meet the processing requirements of the dead edge as a whole.

[0113] S4: Determine whether the pressed edge meets the processing requirements based on the material and processing method:

[0114] The sheet metal materials and processing data are judged. If the sheet metal materials and processing data meet the requirements, proceed to the next step; otherwise, the pressed edge design cannot be performed.

[0115] Furthermore, in S4, the suitability of the pressed edge is determined by the material and processing method. If the sheet metal material and processing data inspection result is cold-galvanized sheet or the surface treatment method is electroplating, the pressed edge design cannot be carried out. The suitability of pressed edge construction is determined from the source to avoid invalid judgments on the pressed edge data in the future.

[0116] First, determine whether the sheet metal material and processing data meet the processing requirements for pressed edges: Cold galvanized sheet is electro-galvanized, and other surface treatments are electroplated parts. After pressing the edges, acid liquid will be trapped inside: After pressing the edges, there will be gaps in the middle. Before painting, the surface will be cleaned with liquid or phosphated. The liquid cannot come out in the gaps, causing the liquid to be wrapped inside when painting or powder coating. Over time, it will rust. If flow occurs, flow marks will appear under the powder coating, resulting in poor appearance.

[0117] Determine whether the pressed-off edge meets the processing requirements by examining the materials and processing methods.

[0118] S5: Determine whether the pressed edge meets the processing requirements based on the sheet metal pressed edge data:

[0119] The sheet metal edge pressing data is checked using the sheet metal edge pressing check function: Let the minimum length of the edge pressing be L and the sheet metal thickness be t. The edge pressing must satisfy the formula L≥5*t. Edge pressing can be designed if it meets the calculation result of the sheet metal edge pressing check function, and cannot be designed if it does not meet the calculation result of the sheet metal edge pressing check function.

[0120] Furthermore, in step S5, if the maximum distances dmax1 and dmax2 simultaneously satisfy dmax1≥5*t and dmax2≥5*t, where t is the thickness of the sheet metal, then the pressed edge meets the sheet metal design specifications.

[0121] This operating method solves the problem of inspecting the pressed edges of sheet metal, avoids processing problems that may be encountered during parts production, and can further encourage design engineers to design products that meet processing requirements, thereby improving the quality of engineers' designs.

[0122] The present invention has been described in the above-described embodiments; however, these embodiments are merely examples for implementing the present invention. It must be noted that the disclosed embodiments do not limit the scope of the present invention. Conversely, any modifications and refinements made without departing from the spirit and scope of the present invention are within the scope of patent protection of the present invention.

Claims

1. A method for inspecting the pressed edges of sheet metal products, characterized in that: Based on 3D design software, the 3D design software includes an entry function interface and an exit function interface, and also includes a sheet metal dead edge check function; The 3D design software is an application used to create and edit 3D models, including SolidWorks, Creo, and WIT 3D; The entry function interface and the exit function interface are development interfaces provided by the 3D design software, used to interface with functions developed and written by the user. The sheet metal dead edge check function is a user-defined, unique function used to perform sheet metal dead edge checks. Specifically, the following steps are included: S1: Open the sheet metal digital model in the 3D design software; The sheet metal digital model is a digital model of the product designed by the engineer. The sheet metal digital model includes a solid model and a sheet metal model. The sheet metal model has the characteristic that the thickness of the same part is consistent. S2: Begin performing sheet metal edge pressing inspection: The sheet metal dead edge inspection function is linked to the sheet metal dead edge inspection function through the 3D design software's entry and exit functions. Sheet metal pressed edges refer to the edges of sheet metal in the form of folded edges; sheet metal pressed edges inspection refers to checking whether the design of the current sheet metal model conforms to the pressed edges design standard. The process of performing sheet metal edge pressing inspection includes: obtaining the material of the model and the surface treatment method of the model; traversing the faces of the sheet metal model and the edges of the sheet metal faces, obtaining the edge data, finding the pressing edges through the algorithm, calculating the minimum length of the pressing edges, and determining whether the minimum length of the pressing edges meets the requirements. S3: Data Acquisition: Includes acquiring sheet metal material and processing data, basic data of sheet metal edges, and data of sheet metal pressed edges. The sheet metal pressed edge data includes the sheet metal pressed edge length, gap, and corner radius; the sheet metal edge basic data includes sheet metal thickness, endpoints of straight edges, center point of arc edges, start point, end point, and arc radius. S4: Determine whether the pressed edge meets the processing requirements based on the material and processing method: The sheet metal materials and processing data are judged. If the sheet metal materials and processing data meet the requirements, proceed to the next step; otherwise, the pressed edge design cannot be performed. S5: Determine whether the pressed edge meets the processing requirements based on the sheet metal pressed edge data: The sheet metal edge pressing data is checked using the sheet metal edge pressing check function: Let the minimum length of the edge pressing be L and the sheet metal thickness be t. The edge pressing must satisfy the formula L≥5*t. Edge pressing can be designed if it meets the calculation result of the sheet metal edge pressing check function. If it does not meet the calculation result of the sheet metal edge pressing check function, edge pressing cannot be designed.

2. The method for inspecting the pressed edges of sheet metal products as described in claim 1, characterized in that: In S4, the material and processing method are used to determine whether the pressed edge meets the processing requirements. If the sheet metal material and processing data inspection result is cold-dip galvanized sheet or the surface treatment method is electroplating, the pressed edge design cannot be performed.

3. The method for inspecting the pressed edges of sheet metal products as described in claim 1, characterized in that: Step S3, obtaining sheet metal pressed-off edge data includes the following sub-steps: S31: Traverse all solid faces of the sheet metal model using the API provided by the 3D design software to obtain the unique identifier ID of the solid face and get the thickness t of the sheet metal; The API stands for Application Programming Interface, which is a convention for connecting different components of a software system. The unique identifier ID of the solid surface refers to the ID number corresponding to each solid surface, and the unique identifier ID of the solid surface is unique in the current sheet metal model; S32: Use the API provided by the 3D design software to cycle through all solid surfaces of the sheet metal model and obtain the type of solid surface, which includes planar and cylindrical surfaces; Collect the cylindrical surfaces and obtain their surface properties through the API provided by the 3D design software. The surface properties include sheet metal surfaces and sheet metal side surfaces. S33: Obtain all solid edges through the API provided by the 3D design software, obtain the unique identifier ID of the solid edge, and obtain the type of the solid edge. The types of solid edges include straight edges and curved edges. The unique identifier ID of the entity edge refers to the ID number corresponding to each entity edge, and the unique identifier ID of the entity edge is unique in the current sheet metal model; Edge attributes can be obtained through the API provided by the 3D design software. Edge attributes include straight edges, which yield the coordinates of the two endpoints; and arc edges, which yield the coordinates of the arc's center point, starting point, ending point, and midpoint. S34: Using the API provided by the 3D design software, cycle through cylindrical surfaces, and filter and determine sheet metal surfaces based on surface type: Traverse the cylindrical surface to obtain two straight edges and two circular arc edges. Let the center coordinates of one arc be P(XP,YP,ZP), the starting point of the arc be E1(X1,Y1,Z1), the ending point be E2(X2,Y2,Z2), and the midpoint of the arc be M(XP,YP,Z2). M Y M Z M Connect E1 and P to obtain line segment E1P, and connect E2 and P to obtain line segment E2P. According to the vector formula: ， ， Let the angle between the vectors be θ. The formula for calculating the angle between vectors is the cosine vector angle formula. ， Solution: ， Once the included angle θ is obtained, similarly, the included angle from the other end point of the cylindrical surface to the center is calculated. When the included angle of both arcs is 180 degrees, the selected edge is determined to be a pressed edge. S35: Connect the midpoint of the arc to the center of the circle to obtain line segment MP. Use the API provided by the 3D design software to obtain the adjacent faces of the sheet metal surface. Loop through the adjacent faces, traversing their edges. Use the API provided by the 3D design software to obtain the endpoints of the edges, collecting the endpoints into a set. Loop through the point set. According to the formula for projecting a point onto a line, let the endpoint of the adjacent face's edge be point A, and let the perpendicular point from point A to line segment MP be C(Xc, Yc, Zc). First, calculate the vector: ， ， ， Based on the perpendicular relationship of vectors; Formula 1 is obtained as follows: ， Point C lies on line segment MP. According to the collinearity of vectors... and Collinearity yields Formula 2 ， Formula 3 is derived from Formula 2. ， Substituting Formula 3 into Formula 1, we can calculate k and obtain Formula 4: ， Finally, substituting k into formula 3, we obtain the perpendicular point C. Using the distance formula, we determine the distance d from the center point P to the perpendicular point C: ， Similarly, the distances from all endpoints on adjacent surfaces to the center of the circle can be obtained. The maximum distance of an adjacent surface is found by looping through the surface. Let the maximum distance be dmax1. According to the above method, another adjacent surface of the cylinder is found. At the same time, the projection of the points on the adjacent surface onto the PM line segment is calculated. Then the distance from the projection point to the center of the circle is calculated. The maximum distance is found by looping through the surface. Let the maximum distance be dmax2.

4. The method for inspecting pressed edges of sheet metal products as described in claim 3, characterized in that: In step S5, if the maximum distances dmax1 and dmax2 simultaneously satisfy dmax1≥5*t and dmax2≥5*t, where t is the thickness of the sheet metal, then the pressed edge meets the sheet metal design specifications.

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