A method for processing and inspecting a u-shaped sheet metal product

Abstract

The application provides a method for processing and checking a U-shaped sheet metal product, comprising the following steps: S1: opening a sheet metal digital model; S2: checking whether the sheet metal model is a U-shaped sheet metal; S3: obtaining sheet metal U-shaped bending data; the sheet metal U-shaped bending data comprises a U-shaped width, a U-shaped height 1 and a U-shaped height 2; S4: judging whether the U-shaped bending meets the requirements. The method simplifies the operation of engineers, automatically analyzes the bending surface and identifies the U-shaped bending process on the three-dimensional design software, does not need manual analysis of the model, and can obtain whether the U-shaped sheet metal bending processing meets the requirements within a few seconds. The method solves the U-shaped bending process checking work, avoids the interference phenomenon that may be encountered during part production, enables engineers who do not understand the bending process to also design products meeting the processing requirements, and improves the design quality of engineers.

Description

Technical Field

[0001] This invention relates to the field of computer science, and more particularly to a method for inspecting the processing of U-shaped sheet metal products. Background Technology

[0002] Sheet metal processing is an indispensable part of machining, especially in industries such as aerospace, home appliances, automobiles, and elevators, where sheet metal parts are widely used. Bending, as the only single-unit forming process in sheet metal processing, is one of the most important. Bending of sheet metal products refers to the processing of changing the direction of the sheet metal or workpiece. When bending U-shaped sheet metal products using a bending machine, two or more bending operations are required. Often, interference occurs when the bending tool and cutting tool collide, making bending impossible or causing deformation. Due to the influence of machine tools and molds, the width and height of the U-shaped bend cannot be too small.

[0003] In the traditional model, sheet metal production involves manually measuring the dimensions of the U-shaped sheet metal, judging based on experience, or manually consulting bending machine data to verify whether interference between the parts and the cutting tools occurs during processing. This process requires a significant amount of time and effort. If product designers are unfamiliar with the bending process, the designed width and height of the U-shaped bent parts may not meet the maximum processing dimensions of the bending machine, leading to production abnormalities, design revisions, and wasting considerable production time, thus affecting the product production schedule. 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 processing of U-shaped sheet metal products.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a method for processing and inspecting U-shaped sheet metal products, based on a U-shaped sheet metal bending inspection system. The U-shaped sheet metal bending inspection system is associated with the 3D software through the input and output functions of the 3D software. The U-shaped sheet metal bending inspection system includes a custom U-shaped sheet metal bending inspection function. Through the custom U-shaped sheet metal bending inspection function, the functions of the U-shaped sheet metal bending inspection system are executed, including traversing the surfaces of the sheet metal model, filtering the sheet metal bending surfaces, obtaining the bending height, obtaining the bending length, obtaining the bending angle, and obtaining the surface ID of the bending surface.

[0006] Specifically, the following steps are included:

[0007] S1: Open the sheet metal digital model;

[0008] Use 3D design software to open the sheet metal digital model; the sheet metal digital model includes a solid model and a sheet metal model.

[0009] The sheet metal model has multiple solid faces, each solid face has a solid face ID, and the edges of the solid faces have edge IDs;

[0010] S2: Check if the sheet metal model is a U-shaped sheet metal;

[0011] S21: Obtain information data from the sheet metal model;

[0012] The information data includes the solid surface information of the sheet metal model and the sheet metal thickness t;

[0013] The entity surface information includes the entity surface ID and the entity surface type, and the entity surface type includes plane and cylindrical surface.

[0014] S22: Loop through all planes and obtain parallel edges;

[0015] S23: Identify and record the plane ID;

[0016] S24: Obtain the bending angle;

[0017] S25: Determine whether the sheet metal model is a U-shaped bent part;

[0018] S3: Obtain sheet metal U-shaped bending data;

[0019] The sheet metal U-shaped bending data includes U-shaped width, U-shaped height 1, and U-shaped height 2;

[0020] S4: Determine whether the U-shaped bend meets the requirements.

[0021] Preferably, step S22 specifically involves collecting all planes, iterating through all collected planes, obtaining all straight edges of the planes through the API provided by the 3D design software, wherein the straight edges include the edge points at both ends; iterating through all straight edges to find parallel straight edges;

[0022] Let plane A be the looping plane. Obtain the straight edges of plane A, and let the endpoints of the obtained straight edges be A1 and B1, respectively. Loop through all the straight edges of plane A, and let the endpoints of the looping straight edges be A2 and B2. Connect points A1 and B1 to obtain line segment AB, and calculate the vector. sum vector Based on the vector cross product, determine whether the calculated distances from A2 to AB and B2 to AB are the same to determine if they are parallel edges; if they are parallel edges, record the solid face ID of the plane and the edge ID of this set of parallel edges.

[0023] Preferably, in step S23, a set of cylindrical surfaces adjacent to the straight edge A1B1 of parallel edges are obtained cyclically according to the edge ID. The cylindrical surfaces adjacent to the parallel edges are obtained through the API provided by the 3D design software. Let the cylindrical surface be B1. Traverse the straight edges of B1 and obtain the plane adjacent to the straight edge of the cylindrical surface through the API. Let the adjacent plane be C1 and record the surface ID of C1. At the same time, the plane C2 adjacent to the straight edge of the cylindrical surface adjacent to the straight edge A2B2 is obtained in the same way. Record the surface ID of C2 and record the plane containing this set of parallel edges as A1 and record the surface ID of A1.

[0024] Preferably, step S24 specifically involves obtaining the vectors of planes A1, C1, and C2 to obtain... , , Let vector A be A(x,y,z), vector C1 be C1(x,y,z), and vector C2 be C2(x,y,z). According to the formula for the angle between vectors, calculate the angle between surface A1 and surface C1, and the angle between surface A1 and surface C2. Determine if the calculated angle is 90°. If it is not 90°, stop executing and return to the engineer for modification.

[0025] Preferably, step S25 specifically involves: obtaining the point sets of surfaces A1, C1, and C2 respectively; connecting the origin O and point A(x,y,z) to obtain line segment OA; assuming a point on surface A1 is A0; calculating the perpendicular from A0 to line segment OA, and setting the foot of the perpendicular as A1; and calculating the perpendicular from A0 to line segment OA using the perpendicular calculation formula. Similarly, assuming a point on surface C1 is C4; calculating the perpendicular from C4 to line segment OA, and calculating the foot of the perpendicular C5; and assuming a point on surface C2 is C6; calculating the perpendicular from C6 to OA, and calculating the foot of the perpendicular C7; connecting points A1 and C5 to obtain line segment A1C5; connecting points A1 and C7 to obtain line segment A1C7; and calculating the vector... and Calculate the angle between two vectors using the vector angle formula. and When the included angle is 0°, the sheet metal model is determined to be a U-shaped bent part; otherwise, the sheet metal model is not a U-shaped bent part.

[0026] Preferably, the width of the U-shape is W1, the height 1 of the U-shape is H1, and the height 2 of the U-shape is H2; step S3 specifically includes:

[0027] S31: Calculate the width W1 of the U-shape;

[0028] Project one point from the set of points on surface C1 onto the vector of surface C1 to obtain point C10. Project one point from the set of points on surface C2 onto the vector of surface C1 to obtain point C20. Let point C10 be (x1, y1, z1) and point C20 be (x2, y2, z2). According to the distance formula, the distance d between surface C1 and surface C2 is obtained. The width of the U-shape W1 = d - 2 * t.

[0029] S32: Calculate the heights H1 and H2 of the U-shape;

[0030] Project all points of the C1 surface point set onto vector A of the A1 surface to obtain the C1 projection point set. Project one point A0 from the A1 surface point set onto vector A of the A1 surface, and set it as point A1. Iterate through the C1 projection point set, and set one point in the C1 projection point set as the loop point. Let the loop point be (x1, y1, z1) and point A1 be (x2, y2, z2). According to the distance formula, obtain the distance set from the C1 projection point set to point A1. Iterate through the distance sets and find the maximum distance dMax1 and the minimum distance dMin1. Then H1 = dMax1 - dMin1.

[0031] S33: Get the minimum height of the U-shape;

[0032] Let H be the minimum height of the U-shape. Calculate H1 and H2 based on S32, compare the sizes of H1 and H2, and take the smaller value of the two as the minimum height H of the U-shape.

[0033] Preferably, step S4 specifically includes:

[0034] S41: Construct a database of bending machine processing requirements;

[0035] The bending machine processing requirements database includes a processing dimension table, which is constructed based on the minimum requirements for the bending machine to process U-shaped dimensions. The processing dimension table includes the sheet metal thickness t and the minimum value of H.

[0036] S42: Determine whether the U-shaped bend meets the requirements;

[0037] Based on the obtained sheet metal thickness t, match the minimum value of H in the processing dimension table, obtain the minimum value of H, compare the minimum height H of the U-shape with the minimum value of H, if the minimum height H of the U-shape is less than or equal to the minimum value of H, then the U-shape bend meets the requirements, otherwise the U-shape bend does not meet the requirements.

[0038] Preferably, if the straight edge A1B1 or A2B2 cannot obtain an adjacent cylindrical surface, the calculation is stopped and the next set of parallel edges is cycled until both A1B1 and A2B2 of the set of parallel edges can obtain an adjacent cylindrical surface. Then, the calculation continues to obtain the plane C1 surface and C2 surface adjacent to the straight edge of the cylindrical surface.

[0039] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The present invention simplifies the operation of engineers. It automatically analyzes the bending surface and identifies the U-shaped bending process on the three-dimensional design software. There is no need for manual analysis of the model. A drawing can be used to determine whether the U-shaped sheet metal bending process meets the requirements in a few seconds. It solves the problem of U-shaped bending process inspection, avoids interference that may be encountered during part production, and allows engineers who do not understand the bending process to design products that meet the processing requirements, thereby improving the design quality of engineers. (2) The present application first determines whether the bending angle of the sheet metal model is 90°. If not, it returns to the design engineer for modification and does not continue to the next step. This makes it easier for the design engineer to find out whether the bending angle of the model is abnormal, ensures high accuracy of the sheet metal model, reduces errors, improves the design quality of the sheet metal model, and reduces the error rate of modeling. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of the sheet metal model for a method of processing and inspecting U-shaped sheet metal products according to the present invention.

[0041] Figure 2 This is a schematic diagram of step S25 of the method for processing and inspecting U-shaped sheet metal products according to the present invention;

[0042] Figure 3 This is a front view of the sheet metal model of the U-shaped sheet metal product processing and inspection method of the present invention;

[0043] Figure 4 This is a schematic diagram of a bending machine for U-shaped bending, which is part of the method for processing and inspecting U-shaped sheet metal products according to the present invention.

[0044] Figure 5 This invention provides a processing dimension table for a method of processing and inspecting U-shaped sheet metal products. Detailed Implementation

[0045] To provide a further understanding of the purpose, structure, features, and functions of the present invention, detailed descriptions are provided below with reference to specific embodiments.

[0046] A method for inspecting the processing of U-shaped sheet metal products is disclosed, based on a U-shaped sheet metal bending inspection system. A 3D design software is associated with the U-shaped sheet metal bending inspection system through an entry function and an exit function. The entry and exit functions are development interfaces provided by the 3D design software, and the U-shaped sheet metal bending inspection system is loaded through these functions. The U-shaped sheet metal bending inspection system includes a custom U-shaped sheet metal bending inspection function, which is the only function used to execute the system. Through this custom function, the system's functions are executed, including traversing the surfaces of the sheet metal model, filtering bending surfaces, obtaining bending height, bending length, bending angle, and obtaining the surface ID of the bending surface.

[0047] After the product design engineer completes the product design, which includes a U-shaped sheet metal part, the engineer analyzes the sheet metal data based on the digital model. Using 3D design software, the engineer opens the digital sheet metal model and executes a U-shaped bending inspection command. The U-shaped sheet metal bending inspection system program uses the API provided by the 3D design software to traverse all sheet metal surfaces, filters the bending surfaces based on their type, calculates the U-shaped bending part using an algorithm, identifies the dimensions of the U-shape using the API provided by the 3D design software, obtains the processing shape of the U-shaped sheet metal, and matches the U-shaped sheet metal dimensions with the processing dimensions of the bending machine to determine if the processing requirements are met. Through simple operation, U-shaped bending inspection is achieved.

[0048] Specifically, the following steps are included:

[0049] S1: Open the sheet metal digital model;

[0050] Using 3D design software, open the sheet metal digital model. The sheet metal digital model includes a solid model and a sheet metal model. The sheet metal model is characterized by a consistent thickness for the same part. The sheet metal model has multiple solid faces, each with a solid face ID, which is a unique identifier for the solid face. The edges of the solid faces have edge IDs.

[0051] S2: Check if the sheet metal model is a U-shaped sheet metal;

[0052] U-shaped sheet metal is a type of workpiece that is bent on both sides, and the shape after bending resembles the letter U.

[0053] Specifically, the following steps are included:

[0054] S21: Obtain information data from the sheet metal model;

[0055] By using the API provided by the 3D design software, all solid faces of the sheet metal model can be traversed to obtain the information data of the sheet metal model.

[0056] The information data includes the solid surface information of the sheet metal model and the sheet metal thickness t;

[0057] The entity surface information includes the entity surface ID and the entity surface type, which includes plane, cylindrical surface, etc.

[0058] S22: Loop through all planes and obtain parallel edges;

[0059] Collect all planes, loop through all collected planes, and obtain all straight edges of the planes using the API provided by the 3D design software. The straight edges include the edge points at both ends of the straight edges. Loop through all straight edges and find the parallel straight edges.

[0060] Specifically: Let the looping plane be plane A, obtain the straight edges of plane A, and let the two ends of the obtained straight edges be A1 and B1 respectively; the looping plane is any plane among all the collected planes; loop through all the straight edges of plane A, and compare whether there is a pair of parallel edges; let the looping straight edge points be A2 and B2; the looping straight edge points are the two ends of any straight edge among all the straight edges of plane A.

[0061] Connect points A1 and B1 to obtain line segment AB. Calculate the vector based on A1-B1. A1-A2 yields the vector ; to vector and The cross product, according to the geometric meaning of the vector cross product, It is actually the area of ​​the parallelogram, according to the parallelogram formula.

[0062]

[0063]

[0064] Calculate the distance d1 from A2 to AB and the distance d2 from B2 to AB respectively; when the distances d1 and d2 are the same, they are determined to be parallel edges, and the solid face ID of the plane and the edge ID of this set of parallel edges are recorded respectively.

[0065] S23: Identify and record the plane ID;

[0066] Based on the edge ID, iteratively obtain a set of cylindrical surfaces adjacent to the straight edge A1B1 of a parallel edge. Using the API provided by the 3D design software, obtain the cylindrical surfaces adjacent to the parallel edges. Let this cylindrical surface be surface B1. Traverse the straight edges of surface B1 and obtain the plane adjacent to the straight edge of the cylindrical surface using the API. Let this adjacent plane be surface C1 and record its surface ID. Similarly, obtain the cylindrical surfaces adjacent to the straight edge A2B2 of the parallel edge. Let this cylindrical surface be surface B2. Traverse the straight edges of surface B2 and obtain the plane adjacent to the straight edge of the cylindrical surface using the API. Let this adjacent plane be surface C2 and record its surface ID. Let the plane containing this set of parallel edges be surface A1 and record its surface ID.

[0067] If neither straight edge A1B1 nor A2B2 can find an adjacent cylindrical surface, the calculation stops, and the next set of parallel edges is retrieved. This process continues until both A1B1 and A2B2 of a set of parallel edges can find adjacent cylindrical surfaces. Then, the calculation continues to retrieve the planes C1 and C2 adjacent to the straight edges of the cylindrical surfaces. By checking for the presence or absence of adjacent cylindrical surfaces, it is determined whether this set of parallel edges is the required parallel edge, improving the speed of plane recognition, reducing the number of system calculations, avoiding redundant calculations, and increasing computational speed.

[0068] S24: Obtain the bending angle;

[0069] The vectors of surfaces A1, C1, and C2 are obtained respectively using the API provided by the 3D design software. , , According to the formula for the angle between vectors:

[0070] Calculate the angle between vector A and vector C1, that is... ;

[0071] Let vector A be A(x,y,z), vector C1 be C1(x,y,z), and vector C2 be C2(x,y,z). Substituting these into the formula, we get...

[0072]

[0073] Calculate cosθ to obtain the angle between planes A1 and C1. Determine if the angle is 90°. If cosθ equals 0, the angle is 90°; otherwise, it is not 90°.

[0074] Similarly, calculate the angle between surfaces A1 and C2, and determine if the angle is 90°. If it is not 90°, return the model to the design engineer for modification and do not continue execution. This allows the design engineer to identify any abnormalities in the model's bending angle, ensuring high accuracy of the sheet metal model, reducing errors, improving the design quality of the sheet metal model, and reducing the modeling error rate.

[0075] S25: Determine whether the sheet metal model is a U-shaped bent part;

[0076] Using the API provided by the 3D design software, obtain the points of surfaces A1, C1, and C2 respectively, resulting in the point sets of surfaces A1, C1, and C2. Let the origin be point O, and connect point O to the vector point A to obtain line segment OA; the vector point A is then represented as A(x,y,z).

[0077] Let A0 be a point on plane A1. Calculate the perpendicular from A0 to the projection onto OA, and let A1 be the foot of the perpendicular. Using the perpendicular calculation formula, calculate the foot of the perpendicular from A0 to line segment OA, A1(x,y,z). Calculate the vector:

[0078]

[0079]

[0080]

[0081] Based on the perpendicular relationship of vectors; The following formula is obtained:

[0082] (Formula 1);

[0083] Point A1 lies on line segment OA. According to the collinearity of vectors... and Collinearity results in:

[0084] (Formula 2)

[0085] From Formula 2, we get:

[0086] (Formula 3)

[0087] Substituting Formula 3 into Formula 1, we can calculate k:

[0088] (Formula 4)

[0089] Finally, substituting k into formula 3, we obtain the perpendicular point A1.

[0090] Similarly, let C4 be one of the points on plane C1. Calculate the perpendicular point C5(x,y,z) from C4 on plane C1 to OA.

[0091] Similarly, let C6 be one of the points on plane C2. Calculate the perpendicular point C7(x,y,z) from point C6 on plane C2 to its projection onto OA.

[0092] Connect points A1 and C5 to obtain line segment A1C5, and calculate the vector. ;

[0093]

[0094] Connect points A1 and C7 to obtain line segment A1C7. Calculate the vector. ;

[0095]

[0096] Calculate the angle between two vectors using the vector angle formula. and When the included angle is 0°, the sheet metal model is determined to be a U-shaped bent part. and When the included angle is 180°, the sheet metal model is determined to be a Z-shaped bending part.

[0097] S3: Obtain sheet metal U-shaped bending data;

[0098] The sheet metal U-shaped bending data includes U-shaped width, U-shaped height 1, and U-shaped height 2; let the U-shaped width be W1, U-shaped height 1 be H1, and U-shaped height 2 be H2.

[0099] S31: Calculate the width W1 of the U-shape;

[0100] Projecting one point from the set of points on surface C1 onto the vector of surface C1, we get point C10. Similarly, projecting one point from the set of points on surface C2 onto the vector of surface C1, we get point C20. Let point C10 be (x1, y1, z1) and point C20 be (x2, y2, z2). According to the distance formula...

[0101] The distance d between surfaces C1 and C2 is obtained, and the width of the U-shape W1 is calculated as d - 2 * t.

[0102] S32: Calculate the heights H1 and H2 of the U-shape;

[0103] Project all points from the C1 surface point set onto vector A on the A1 surface to obtain the C1 projection point set. Project one point A0 from the A1 surface point set onto vector A on the A1 surface, and set it as point A1. Repeat this process for the C1 projection point set, with one point in the C1 projection point set being the loop point. Let the loop point be (x1, y1, z1) and point A1 be (x2, y2, z2). According to the distance formula... Obtain the set of distances from the projection point set of C1 to point A1, and iteratively compare the distance sets to find the maximum distance d. Max1 and minimum distance d Min1 Then H1=d Max1 -d Min1 ;

[0104] Similarly, project all points from the C2 surface point set onto vector A on the A1 surface to obtain the C2 projection point set. Project one point A0 from the A1 surface point set onto the vector A on the A1 surface, and set it as point A1. Iterate through the C2 projection point set, setting the iteration point as (x1, y1, z1) and point A1 as (x2, y2, z2). According to the distance formula, obtain the distance set from the C2 projection point set to point A1. Iterate through and compare the distance sets to find the maximum distance d. Max2 and minimum distance d Min2 Then H2=d Max2 -d Min2 .

[0105] S33: Get the minimum height of the U-shape;

[0106] Let H be the minimum height of the U-shape, where H is the minimum value of H1 and H2.

[0107] Based on the calculated H1 and H2 from S32, compare the sizes of H1 and H2, and obtain the smaller value as the minimum height H of the U-shape.

[0108] S4: Determine whether the U-shaped bend meets the requirements;

[0109] S41: Construct a database of bending machine processing requirements;

[0110] The bending machine processing requirements database includes a processing dimension table, which is constructed based on the minimum requirements for the bending machine to process U-shaped dimensions. The processing dimension table includes the sheet metal thickness t and the minimum value of H.

[0111] S42: Determine whether the U-shaped bend meets the requirements;

[0112] Based on the obtained sheet metal thickness t, match the minimum value of H in the processing dimension table, obtain the minimum value of H, compare the minimum height H of the U-shape with the minimum value of H, if the minimum height H of the U-shape is less than or equal to the minimum value of H, then the U-shape bend meets the requirements, otherwise the U-shape bend does not meet the requirements.

[0113] 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 of processing inspection of a U-shaped sheet metal product, characterized by: The U-shaped sheet metal bending inspection system is associated with the three-dimensional software through an entry function and an exit function of the three-dimensional software; the U-shaped sheet metal bending inspection system comprises a self-defined U-shaped sheet metal bending inspection function, through which the function of the U-shaped sheet metal bending inspection system is executed, including traversing the faces of the sheet metal model, filtering the sheet metal bending faces, obtaining the bending height, obtaining the bending length, obtaining the bending angle, and obtaining the face ID of the bending face; Specifically comprising the following steps: S1: opening a sheet metal digital model; A three-dimensional design software is used to open a sheet metal digital model; the sheet metal digital model comprises an entity model and a sheet metal model; The sheet metal model has a plurality of entity faces, each of which has an entity face ID, and the edges of the entity face have edge IDs; S2: checking whether the sheet metal model is a U-shaped sheet metal; S21: obtaining information data of the sheet metal model; The information data comprises entity face information of the sheet metal model and a sheet metal thickness t; The entity face information comprises an entity face ID and a type of the entity face, and the type of the entity face comprises a plane and a cylindrical face; S22: obtaining parallel edges by circulating all planes; S23: identifying and recording the face ID of the plane; S24: obtaining a bending angle; S25: judging whether the sheet metal model is a U-shaped bending piece; S3: obtaining U-shaped sheet metal bending data; The U-shaped sheet metal bending data comprises a U-shaped width, a U-shaped height 1, and a U-shaped height 2; Let the U-shaped width be W1, the U-shaped height 1 be H1, and the U-shaped height 2 be H2; S31: calculating the U-shaped width W1; Project one of the points in the C1 face point set onto the vector of the C1 face to obtain a C10 point, and project one of the points in the C2 face point set onto the vector of the C1 face to obtain a C20 point; let the C10 point be (x1, y1, z1) and the C20 point be (x2, y2, z2); obtain the distance d between the C1 face and the C2 face according to the distance formula, and the U-shaped width W1 is d-2*t; S32: calculating the U-shaped heights H1 and H2; Project all points in C1 face point set to vector A of A1 face, get C1 projection point set, project one point A0 in A1 face point set to vector A of A1 face, set as A1 point, loop to calculate C1 projection point set, one point in C1 projection point set is loop point, set loop point as (x1, y1, z1), A1 point as (x2, y2, z2), according to distance formula, get distance set of C1 projection point set to A1 point, loop to compare distance set, find maximum distance d Max1 and minimum distance d Min1 , then H1=d Max1 -d Min1 ; Project all points of C2 face point set to vector A of A1 face, get C2 projection point set, project one point A0 of A1 face point set to vector of A1 face, set as A1 point, loop to calculate C2 projection point set, set loop point as (x1, y1, z1), A1 point as (x2, y2, z2), according to distance formula, get distance set of C2 projection point set to A1 point, loop to compare distance set, find maximum distance d Max2 and minimum distance d Min2 , then H2 = d Max2 -d Min2 ; S33: obtaining a U-shaped minimum height; Let the U-shaped minimum height be H; compare H1 and H2 according to the calculated H1 and H2 in S32, and obtain the smaller value of the two as the U-shaped minimum height H; S4: judging whether the U-shaped bending meets the requirements; S41: constructing a bending machine processing requirement database; The bending machine processing requirement database comprises a processing size table, which is constructed according to the minimum requirement of the U-shaped size that can be processed by the bending machine; the processing size table comprises a sheet metal thickness t and an H minimum value; S42: judging whether the U-shaped bending meets the requirements; Match the H minimum value in the processing size table with the obtained sheet metal thickness t to obtain the H minimum value; compare the U-shaped minimum height H with the H minimum value; if the U-shaped minimum height H≤H minimum value, the U-shaped bending meets the requirements; otherwise, the U-shaped bending does not meet the requirements.

2. The method of U-shaped sheet metal product processing inspection according to claim 1, characterized in that: Step S22 specifically comprises collecting all planes, circulating all the collected planes, obtaining all straight edges of the planes through an API provided by the three-dimensional design software, the straight edges comprising straight edge points at both ends; and finding parallel straight edges by circulating all the straight edges. Let the circulation plane be A plane, get the straight side of A plane, let the straight side edge points of the two ends of the obtained straight side be A1 and B1; circulate all the straight sides of A plane, let the circulation straight side edge points be A2 and B2; connect A1 and B1 points to obtain a line segment AB, calculate vectors and , ; according to vector cross product, according to whether the distance from A2 to AB and the distance from B2 to AB are the same, judge whether it is a parallel side; if it is a parallel side, record the entity plane ID of the plane and the edge ID of the parallel side.

3. The method of U-shaped sheet metal product processing inspection according to claim 2, characterized in that: Step S23 obtains a set of straight edges A1B1 adjacent to the cylindrical surface according to the edge ID, obtains the cylindrical surface adjacent to the parallel edges through the API provided by the three-dimensional design software, assumes that the cylindrical surface is B1 surface, traverses the straight edges of B1 surface, obtains the plane C1 surface adjacent to the straight edges of the cylindrical surface through the API, records the surface ID of C1 surface, at the same time, obtains the plane C2 surface adjacent to the straight edges of the straight edges A2B2 adjacent to the cylindrical surface in the same way, records the surface ID of C2 surface, records the plane A1 surface where the set of parallel edges is located, and records the surface ID of A1 surface.

4. The method of U-shaped sheet metal product processing inspection according to claim 3, characterized in that: Step S24 is specifically to obtain vectors of A1 plane, C1 plane and C2 plane, and get , , wherein vector A is A(x, y, z), vector C1 is C1(x, y, z), and vector C2 is C2(x, y, z); according to the vector angle formula, the angle between A1 plane and C1 plane and the angle between A1 plane and C2 plane are calculated, and it is judged whether the calculated angle is 90°. If not, it is not continued to be executed downward, and the engineer is returned to modify.

5. The method of U-shaped sheet metal product processing inspection according to claim 4, characterized in that: The step S25 specifically comprises: acquiring the point set of the A1 plane, the point set of the C1 plane, and the point set of the C2 plane respectively, connecting the coordinate origin O point and the point A (x, y, z) to obtain a line segment OA, assuming that one of the points of the A1 plane is A0 point, calculating the foot point A1 of the A0 point to the line segment OA, and calculating the foot point A1 of the A0 point to the line segment OA through the foot point calculation formula; in the same way, assuming that one of the points of the C1 plane is C4 point, calculating the foot point C5 of the C4 point to the line segment OA, calculating the foot point C5 of the C4 point to the line segment OA, assuming that one of the points of the C2 plane is C6 point, calculating the foot point C7 of the C6 point to the line segment OA, and calculating the foot point C7 of the C6 point to the line segment OA; connecting the A1 and C5 points to obtain a line segment A1C5, connecting the A1 and C7 points to obtain a line segment A1C7, and calculating vectors and According to the vector angle formula, when the angle between the vectors and is 0°, it is judged that the sheet metal model is a U-shaped bending piece, otherwise, the sheet metal model is not a U-shaped bending piece.

6. The method of U-shaped sheet metal product processing inspection according to claim 3, characterized in that: If the straight edges A1B1 or A2B2 cannot obtain the adjacent cylindrical surface, the calculation is not performed, the next set of parallel edges is cycled, until the A1B1 and A2B2 of the set of parallel edges can obtain the adjacent cylindrical surface, then the calculation of obtaining the planes C1 surface and C2 surface adjacent to the straight edges of the cylindrical surface is continued.

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