Preparation method and use method of three-dimensional sample plate for bending sheet metal parts

Abstract

The invention discloses a preparation method and a use method of a three-dimensional template of a bent sheet metal part in the technical field of process assembly design and manufacturing. The preparation method comprises the following steps: S1, obtaining all appearance characteristic data of a to-be-measured surface of the bent sheet metal part to form a preparation data set; and S2, establishing a process model surface of the three-dimensional template through three-dimensional software based on the preparation data set. And S3, based on the process model surface, establishing a three-dimensional template process mathematical model by taking a preset value W as a thickness value through three-dimensional software. And S4, importing data of the three-dimensional template process mathematical model into additive manufacturing slicing software, and carrying out two-dimensional slicing treatment to obtain three-dimensional template parameters. And S5, the additive manufacturing equipment conducts 3D printing based on the three-dimensional sample plate parameters, and three-dimensional sample plate preparation is completed. According to the preparation method of the three-dimensional sample plate, time and cost for drawing a large amount of drawings are reduced, and on the basis, preparation of the three-dimensional sample is rapidly completed with low cost by utilizing the characteristics of 3D processing customized products.

Description

Technical Field

[0001] This invention relates to the field of process assembly design and manufacturing technology, and in particular to a method for preparing and using a three-dimensional template for bent sheet metal parts. Background Technology

[0002] In the aerospace parts manufacturing industry, sheet metal parts constitute the vast majority, with bent sheet metal parts being a crucial component. Their production quality and efficiency are key factors affecting the overall aircraft production. High-precision templates are needed to inspect the dimensional accuracy of sheet metal parts, such as their shape, hole positions, and angles, thereby ensuring the quality of the sheet metal parts. The shape and hole positions of the inspection template provide feedback on the surface shape of the sheet metal part. Traditional inspection templates are flat, which can meet the needs of general sheet metal parts for planar use and inspection. Positioning is mainly achieved through hole positions and the edge shape of the sheet metal part, with template alignment and deviation judgment performed visually.

[0003] For sheet metal parts with multiple bends or requiring positioning, traditional flat inspection templates are difficult to use for effective dimensional positioning and inspection, limiting their application in the inspection process. Currently, the processing and use of 3D templates is largely unexplored. This is because creating 3D templates using traditional flat fabrication methods is difficult. Firstly, a corresponding 3D template drawing is required for each sheet metal part, matching the number of sheet metal parts produced, incurring drafting costs. Secondly, due to the bending process, 3D templates cannot be processed using the same methods as flat templates. Using current sheet metal part processing methods would exceed the cost of bending sheet metal. Because of the diverse types but relatively small quantities required, 3D templates are custom-made, making their production extremely costly. Summary of the Invention

[0004] To overcome the above-mentioned shortcomings of the prior art, the technical problem to be solved by the present invention is: how to reduce the cost of manufacturing three-dimensional prototypes.

[0005] The technical solution adopted by this invention to solve its technical problem is: A method for preparing a three-dimensional template for bent sheet metal parts includes the following steps: S1: Obtain all the shape feature data of the surface to be tested of the bent sheet metal part to form a preparation dataset.

[0006] S2, based on the preparation dataset, uses 3D software to create a process model surface for a three-dimensional template.

[0007] S3, based on the process model surface, a three-dimensional template process digital model is established using three-dimensional software with a preset thickness value W.

[0008] S4. Import the data of the 3D template process model into the additive manufacturing slicing software, perform 2D slicing processing, and obtain the 3D template parameters.

[0009] S5, the additive manufacturing equipment performs 3D printing based on the parameters of a 3D template to complete the preparation of the 3D template.

[0010] Furthermore, the material selected for 3D printing in step S5 above is AlSi10Mg.

[0011] Furthermore, the software used to create the three-dimensional template process model surface in step S2 above is CATIA software.

[0012] Furthermore, the preset value W in step S3 is 5mm.

[0013] The method for using a 3D template for bent sheet metal parts includes the following steps: N1, a three-dimensional template manufactured using any one of the above-mentioned three-dimensional template preparation methods for bent sheet metal parts, wherein one side is selected from each of the two sets of side edges of the surface to be measured of the bent sheet metal part as a first positioning edge, and the side edge corresponding to the two first positioning edges on the process model surface of the three-dimensional template is selected as a second positioning edge.

[0014] N2, the test surface of the bent sheet metal part is fitted with the process model surface of the corresponding three-dimensional template, so that the first positioning edge and the corresponding second positioning edge are aligned.

[0015] N3. Determine whether the shape feature data of the bent sheet metal part and the 3D template are consistent. If they are consistent, proceed to the next step. If there are inconsistencies in the shape feature data, the bent sheet metal part is unqualified.

[0016] N4. Measure the fit between the process model surface of the 3D template and the test surface of the bent sheet metal part at all bending points. Determine whether the measured fit is within the detection range. If all fits are within the range, the bent sheet metal part is qualified. If any fit is outside the range, the bent sheet metal part is unqualified.

[0017] Furthermore, in step N4 above, the tool used to determine the fit between the test surface of the bent sheet metal part and the process model surface of the fitted three-dimensional template is a feeler gauge.

[0018] Furthermore, the range of the detection values ​​in step N4 above is consistent with the tolerance value of the bending radius at the corresponding bend of the bent sheet metal part.

[0019] The beneficial effects of this invention are: This method for preparing a three-dimensional template involves acquiring all the shape feature data of the surface to be measured on a bent sheet metal part to form a preparation dataset, establishing the process model surface of the three-dimensional template, and then establishing a process digital model of the three-dimensional template. Subsequently, a three-dimensional template is produced by 3D printing, which only limits the shape feature data of the process model surface. This ensures the accuracy of subsequent measurements of the three-dimensional template while reducing the time and cost of drawing a large number of drawings. At the same time, by utilizing the customized production characteristics of 3D processing, the processing cost of the three-dimensional template is reduced. Attached Figure Description

[0020] Figure 1 This is one of the schematic diagrams of the structure of the bent sheet metal part in the three-dimensional template preparation method of the bent sheet metal part of the present invention; Figure 2 This is the second schematic diagram of the structure of the bent sheet metal part in the three-dimensional template preparation method of the bent sheet metal part of the present invention; Figure 3 yes Figure 1 Front view of the middle bend surface A; Figure 4 yes Figure 1 Front view of the middle bend surface C; Figure 5 yes Figure 1 Side view; Figure 6 yes Figure 1 Schematic diagram of the structure of the process model surface; Figure 7 This is one of the schematic diagrams of the three-dimensional sample detection corresponding to the three-dimensional sample of the bent sheet metal parts in the three-dimensional sample usage method of the present invention; Figure 8 This is the third schematic diagram of the structure of the bent sheet metal part in the three-dimensional template preparation method of the bent sheet metal part of the present invention; Figure 9 This is the fourth schematic diagram of the structure of the bent sheet metal part in the three-dimensional template preparation method of the bent sheet metal part of the present invention; Figure 10 This is the fifth schematic diagram of the structure of the bent sheet metal part in the three-dimensional template preparation method of the bent sheet metal part of the present invention; Figure 11 This is the sixth schematic diagram of the structure of the bent sheet metal part in the three-dimensional template preparation method of the bent sheet metal part of the present invention; Figure 12 yes Figure 8 Schematic diagram of the structure of the process model surface; Figure 13 This is the second schematic diagram of the three-dimensional sample detection of the corresponding bent sheet metal part in the three-dimensional sample usage method of the present invention. Figure 14This is one of the operation screenshots of CATIA software in the method for preparing a three-dimensional template of bent sheet metal parts according to the present invention; Figure 15 This is the second screenshot of CATIA software operation in the method for preparing a three-dimensional template of bent sheet metal parts according to the present invention. Figure 16 This is the third schematic diagram of the three-dimensional sample detection of the corresponding bent sheet metal part in the three-dimensional sample usage method of the present invention.

[0021] The markings in the figure are as follows: 1-the surface to be tested of the bent sheet metal part, 2-the process model surface, 3-the first positioning edge, 4-the second positioning edge, 5-the bent surface A, 6-the non-bent surface B, 7-the bent surface C, 8-the bent sheet metal part, 9-the three-dimensional template, 10-the non-bent surface K, 11-the bent surface L. Detailed Implementation

[0022] The invention will be further described below with reference to the accompanying drawings.

[0023] Example 1 like Figures 1-7 As shown, the method for preparing a three-dimensional template 9 for a bent sheet metal part 8 includes the following steps: S1, acquiring all the shape feature data of the surface to be measured of the bent sheet metal part 8 to form a preparation dataset. The preparation dataset includes all the shape feature data of the surface to be measured, such as the outline, aperture, bend length, bend height, bending radius, and bending length. Personnel can collect the shape feature data of the bent sheet metal part 8 using a digital model of the bent sheet metal part 8. The specific steps for acquiring all the shape feature data of the surface to be measured of the bent sheet metal part 8 to form the preparation dataset are as follows: Step 1: Divide the bent sheet metal part 8 to be measured into one non-bending surface and V bending surfaces; where V is the number of bends in the bent sheet metal part 8. Step 2: Extract the corresponding shape feature data based on the non-bending surface; Step 3: Determine whether it is a single-sided bend or a double-sided bend based on the non-bending surface. If it is a single-sided bend, extract the shape feature data of the bend surface sequentially from the direction closer to the non-bending surface to the direction farther away from the non-bending surface. If it is a double-sided bend, first select one of the two sides and extract the shape feature data of the bend surface sequentially from the direction closer to the non-bending surface to the direction farther away from the non-bending surface. After the shape feature data of the bend surface on that side has been extracted, extract the shape feature data of the bend surface sequentially from the other side from the direction closer to the non-bending surface to the direction farther away from the non-bending surface.

[0024] S2. Based on the preparation dataset, establish the process model surface 2 of the 3D template 9; this step can be performed using SOLIDWORKS software. The process model surface 2 is a 3D curved surface diagram. S3. Based on the process model surface 2, use 3D software to establish the process digital model of the 3D template 9 with a preset thickness value W; this step can be performed using SOLIDWORKS software, and the extrusion finger can be used to complete the establishment of the process digital model of the 3D template 9. S4. Import the data of the process digital model of the 3D template 9 into the additive manufacturing slicing software, perform 2D slicing processing, and obtain the parameters of the 3D template 9; set the process digital model of the 3D template 9 to "STL" format (because the additive manufacturing slicing software supports importing common formats such as STL and OBJ, it is necessary to convert the data of the process digital model of the 3D template 9 into a format that the additive manufacturing slicing software can support to ensure printability). After the process digital model of the 3D template 9 is imported into the additive manufacturing slicing software, the additive manufacturing slicing software performs slicing processing on the 3D template 9 process digital model to obtain the parameters of the 3D template 9. S5, the additive manufacturing equipment performs 3D printing based on the parameters of the stereo template 9, and completes the preparation of the stereo template 9.

[0025] like Figure 1 The image shows a bent sheet metal part with bends on both sides. The corresponding three-dimensional template 9 is prepared using the following steps: S1, acquiring all the shape feature data of the tested surface of the bent sheet metal part 8 to form a preparation dataset. Personnel collect the shape feature data of the bent sheet metal part 8 using a digital model of the part. The specific steps are as follows: Step 1: The tested surface of the bent sheet metal part 8 includes a sequentially connected bent surface A5, a non-bent surface B6, and a bent surface C7, including one non-bent surface and two bent surfaces. Step 2: Using the non-bent surface B6 as a reference, extract its corresponding shape feature data. The direction during the extraction process is... Figure 2 The indicated orientation is the reference. For example... Figure 2 As shown, the shape feature data of the non-bent surface B6 includes a rectangular outline containing a rectangular hole. The long side of the rectangular outline is valued as B1, and the short side as B2. The long side of the rectangular hole is valued as B3, and the short side as B4. The distance between the long side below the rectangular hole and the short side below the rectangular outline is valued as B5. The distance between the short side on the left side of the rectangular hole and the long side on the left side of the rectangular outline is valued as B6. The shape feature data of the non-bent surface B6 has been extracted. Step 3: Judgment based on the non-bent surface B6 Figure 1 The sheet metal bending part in the image is a double-sided bend. Therefore, first select one of the two sides, i.e., select the bending surface A5, to extract the shape feature data of the bending surface. The direction during the extraction process is based on... Figure 2 The indicated orientation is the reference. For example... Figure 5The external features of the bent surface A5 shown include the bending angle A6, the radius of the bending angle A7, and the bending height A11 (an important parameter in machining and sheet metal design, referring to the vertical distance from the bending start point (or the start point of the inner bend fillet) to the free end (or outer edge) of the bend after the material is bent). It also includes a rectangular outline with a long side value of A8 (A8 is equal to B2), a short side value of A1, and two right angles on the side of the rectangular outline furthest from the non-bent surface B6 with a fillet radius of A9. The bend surface A5 contains two holes, F1 and F2, both with a diameter of A10. The distance between the center of hole F1 and the left short side of the rectangular outline of bend surface A5 is A2. The distance between the centers of holes F1 and F2 is A3. The distances between the centers of holes F1 and F2 and the upper long side of the rectangular outline of bend surface A5 are equal, both A5. The distance between the center of hole F2 and the right short side of the rectangular outline of bend surface A5 is A4. The shape feature data of bend surface A5 is now extracted. Next, shape feature data is extracted from the other bend surface C7. The direction of the extraction process is based on... Figure 2 The indicated orientation is the reference. For example... Figure 5 As shown, the external features of the bent surface C7 include the bending angle C7, the radius of the bending angle C8, and the bending height C12. It also includes a rectangular outline with rounded corners on the two outer sides, where the radius of the rounded corners is C10, the long side of the rectangular outline is C8 (C8 is equal to B2 in the non-bent surface B6), and the wide side of the rectangular outline is C1. The bent surface C7 contains four holes, H1, H2, H3, and H4, each with a diameter of C11. The distance between the center of hole H1 and the left short side of the rectangular outline of the bent surface C7 is C2; the distance between the center of hole H1 and the center of hole H2 is C3; the distance between the center of hole H2 and the center of hole H3 is C4; the distance between the center of hole H3 and the center of hole H4 is C5; the distance between the center of hole H4 and the right short side of the rectangular outline of the bent surface C7 is C6; and the distance between the center of each of the four holes and the lower long side of the rectangular outline of the bent surface C7 is equal at C12. The shape feature data of the bent surface C7 has been extracted, and the dataset preparation is complete.

[0026] S2, based on the above-mentioned preparation dataset, use SOLIDWORKS software to create the process model surface 2 of the three-dimensional template 9. The final process model surface 2 is as follows: Figure 6 As shown, surface 2 of the process model is a three-dimensional curved surface diagram. S3, based on Figure 6The process model surface 2 shown is used to create a 3D template 9 process model using SOLIDWORKS software with a preset thickness value W. The creation of the 3D template 9 process model can be completed using the stretching command. S4: The data of the 3D template 9 process model is imported into the additive manufacturing slicing software for 2D slicing processing to obtain the parameters of the 3D template 9. The 3D template 9 process model is set to "STL" format. After the 3D template 9 process model is imported into the additive manufacturing slicing software, the software slices the 3D template 9 process model to obtain the parameters of the 3D template 9. S5: The additive manufacturing equipment performs 3D printing based on the parameters of the 3D template 9 to complete the preparation of the 3D template 9. The corresponding 3D template 9 is as follows: Figure 7 As shown.

[0027] Example 2 like Figure 8-13 As shown, the difference between this embodiment and Embodiment 1 is that the sheet metal bending part is as follows: Figure 8 The single-sided bent sheet metal part 8 shown, and the corresponding three-dimensional template 9 preparation method includes the following steps: S1, acquiring all the shape feature data of the surface to be tested of the bent sheet metal part 8 to form a preparation dataset. Personnel collect the shape feature data of the bent sheet metal part 8 through the digital model of the bent sheet metal part 8. Step 1: The surface to be tested of the bent sheet metal part 8 includes a sequentially bent surface L11 and a non-bent surface K10, including one non-bent surface and one bent surface. Step 2: Using the non-bent surface K10 as a reference, first extract its corresponding shape feature data. The direction during the extraction process is based on... Figure 9 The indicated orientation is the reference. The shape feature data of the non-bent surface K10 includes a rectangular outline, where the long side of the rectangular outline has a value of K1 and the short side has a value of K2. The two right angles of the rectangular outline of the non-bent surface K10 on the side away from the bent surface L11 are rounded corners with a radius of K3. The shape feature data of the non-bent surface K10 has been extracted. Step 3: Judgment based on the non-bent surface K10 Figure 8 If the sheet metal bending part is a single-sided bend, then the shape feature data of the bending surface L11 is extracted starting from the bending side. The direction during the extraction process is based on... Figure 10 The indicated orientation is the reference. For example... Figure 11As shown, the external features of the bent surface L11 include a bending angle L10, a bending radius L12, a bending height L6, and a rectangular outline. The longer side of the rectangular outline of the bent surface L11 is L1, the shorter side is L2, and the two right angles on the side of the rectangular outline of the bent surface L11 away from the non-bent surface K10 are rounded with a radius of L11. The bent surface L11 contains three holes O1, O2, O3, and O4, each with a diameter of L4. The center of hole O1 is located at the bend. The distance between the short sides on the left side of the rectangular outline of the bent surface L11 is L3; the distance between the center of hole O1 and the center of hole O2 is L5; the distance between the center of hole O2 and the center of hole O3 is L6; the distance between the center of hole O3 and the short side on the right side of the rectangular outline of the bent surface L11 is L7; and the distance between the center of each of the three holes and the upper long side of the rectangular outline of the bent surface L11 is equal to L8. The extraction of the shape feature data of the bent surface L11 is complete, and the dataset preparation is complete.

[0028] S2, based on the above-mentioned preparation dataset, use SOLIDWORKS software to create the process model surface 2 of the three-dimensional template 9. The final process model surface 2 is as follows: Figure 12 As shown, surface 2 of the process model is a three-dimensional curved surface diagram. S3, based on Figure 12 The process model surface 2 shown is used to create a 3D template 9 process model using SOLIDWORKS software with a preset thickness value W. The creation of the 3D template 9 process model can be completed using the stretching command. S4: The data of the 3D template 9 process model is imported into the additive manufacturing slicing software for 2D slicing processing to obtain the parameters of the 3D template 9. The 3D template 9 process model is set to "STL" format. After the 3D template 9 process model is imported into the additive manufacturing slicing software, the software slices the 3D template 9 process model to obtain the parameters of the 3D template 9. S5: The additive manufacturing equipment performs 3D printing based on the parameters of the 3D template 9 to complete the preparation of the 3D template 9. The corresponding 3D template 9 is as follows: Figure 13 As shown.

[0029] Example 3 like Figures 14-15 As shown, the difference between this embodiment and Embodiment 1 is that the material selected for 3D printing in step S5 is AlSi10Mg. AlSi10Mg is an aluminum-silicon-magnesium cast aluminum alloy with approximately 10% silicon and 0.2%-0.6% magnesium as its core components, possessing lightweight, high strength, good casting performance, and corrosion resistance. The preferred composition of AlSi10Mg is shown in Table 1. Based on the room temperature tensile test values ​​in Table 2, the hardness test values ​​in Table 3, and the product density and compactness test values ​​in Table 4, it can be seen that the three-dimensional template 9 made using AlSi10Mg with the above composition meets the current requirements for three-dimensional template 9.

[0030] Table 1 Chemical composition of alloy powder (wt / %) Table 2 Measured values ​​of room temperature tensile strength Table 3 Measured Hardness Values Table 4 Measured values ​​of product density and compactness Preferably, in the method for preparing the three-dimensional template 9 of the bent sheet metal part 8, the software used to establish the process model surface 2 of the three-dimensional template 9 in step S2 of Example 1 or Example 2 can be CATIA software. In step S3, the three-dimensional software used to establish the process digital model of the three-dimensional template 9 based on the process model surface 2 with a preset thickness value W is CATIA software. Figure 14 As shown, in CATIA software, through multiple extractions, process model surface 2 is selected. Then, as... Figure 15 As shown, by thickening the curved surface and selecting the thickening direction and thickness, the 3D template 9 process digital model can be established. Figure 14 The thickness W is 3.5mm, and the preferred preset value W is 5mm. This design ensures that the three-dimensional template 9 will not break frequently due to excessive thinness.

[0031] Example 4 like Figure 7 , Figure 13 and Figure 16 As shown, the method for using a 3D template for bending sheet metal parts includes the following steps: N1, the three-dimensional template 9 manufactured using the three-dimensional template 9 preparation method of any one of Examples 1-3 of the above, selects one side from each of the two sets of side edges of the surface to be tested of the bent sheet metal part 8 as the first positioning edge 3, and selects the side edge on the process model surface 2 of the three-dimensional template 9 corresponding to the two first positioning edges 3 as the second positioning edge 4.

[0032] N2, the test surface of the bent sheet metal part 8 is fitted with the process model surface 2 of the corresponding three-dimensional template 9, so that the first positioning edge 3 and the corresponding second positioning edge 4 are aligned.

[0033] N3. Determine whether the shape feature data of the bent sheet metal part 8 and the three-dimensional template 9 are consistent. Personnel can visually compare whether the outer contours of the bent sheet metal part 8 and the three-dimensional template 9 are aligned, and at the same time observe whether the holes on the three-dimensional template 9 are aligned with the holes on the bent sheet metal part 8. If all the shape feature data are consistent, proceed to the next step. If there are inconsistent shape feature data, such as the outline of the bent sheet metal part 8 not being aligned with the outline of the three-dimensional template 9, or the holes on the bent sheet metal part 8 not being aligned with the corresponding holes, if there is one inconsistent shape feature data that can be detected by the naked eye, it means that the bent sheet metal part 8 is unqualified.

[0034] N4. Measure the fit at all bending points between the process model surface 2 of the 3D template 9 and the test surface of the bent sheet metal part 8. Determine if the measured fit is within the detection range. If all fits are within the range, the bent sheet metal part 8 is qualified; if any fit is outside the range, the bent sheet metal part 8 is unqualified. This step mainly measures whether the bending radius of the bending points between the mutually fitted 3D template 9 and the bent sheet metal part 8, which are not visible to the naked eye, meets the standard. Preferably, the tool used in step N4 to determine the fit between the test surface of the bent sheet metal part 8 and the process model surface 2 of the fitted 3D template 9 is a feeler gauge. This tool can quickly check the fit between the test surface of the bent sheet metal part and the process model surface 2 of the fitted 3D template 9, improving detection efficiency. The detection range in step N4 is consistent with the tolerance value of the bending radius at the corresponding bending point of the bent sheet metal part 8.

[0035] Currently, the inspection of bent sheet metal parts 8 mainly relies on flat inspection templates, calipers, and R-gauges for measurement. This process is cumbersome and prone to errors. Furthermore, as the number of bent sheet metal parts 8 increases, the number of flat templates required also increases, making storage inconvenient. This embodiment utilizes a three-dimensional template to quickly inspect the quality of bent sheet metal parts 8, improving inspection efficiency.

[0036] In summary, this application proposes a method for preparing and using a three-dimensional template 9 for bent sheet metal parts 8. By preparing a dataset, a process model surface 2 of the three-dimensional template 9 is established, followed by the creation of a process digital model of the three-dimensional template 9. Subsequently, the three-dimensional template 9 is fabricated using 3D printing. Compared to traditional manufacturing methods, this significantly reduces the time and cost of drawing blueprints. Furthermore, leveraging the characteristics of 3D processing for customized products, the preparation of the three-dimensional sample is completed quickly and at low cost. Simultaneously, using the three-dimensional template 9 for inspecting bent sheet metal parts 8, compared to traditional measurement methods, only requires one application and alignment, along with a feeler gauge, to measure the external dimensions of the bend. This is faster, more convenient, and allows for accurate and effective inspection of whether the bent sheet metal parts 8 meet the qualification standards, significantly reducing manpower and material resources.

Claims

1. A method for preparing a three-dimensional template for bent sheet metal parts, characterized in that, Includes the following steps: S1, acquire all the shape feature data of the test surface of the bent sheet metal part (8) to form a preparation dataset; S2, Based on the preparation dataset, the process model surface (2) of the three-dimensional template (9) is established using three-dimensional software; S3, Based on the process model surface (2), a three-dimensional template (9) process digital model is established using three-dimensional software with a preset value W as the thickness value; S4. Import the data of the process model of the three-dimensional template (9) into the additive manufacturing slicing software, perform two-dimensional slicing processing, and obtain the parameters of the three-dimensional template (9); S5, the additive manufacturing equipment performs 3D printing based on the parameters of the three-dimensional template (9) to complete the preparation of the three-dimensional template (9).

2. The method for preparing a three-dimensional template for bent sheet metal parts as described in claim 1, characterized in that: The material selected for 3D printing in step S5 is AlSi10Mg.

3. The method for preparing a three-dimensional template for bent sheet metal parts as described in claim 1, characterized in that: The software used to create the process model surface (2) of the three-dimensional template (9) in step S2 is CATIA software.

4. The method for preparing a three-dimensional template for bent sheet metal parts as described in claim 1, characterized in that: The preset value W in step S3 is 5mm.

5. The method of using three-dimensional templates for bent sheet metal parts, characterized by: Includes the following steps: N1, a three-dimensional template (9) for a bent sheet metal part (8) is manufactured using the three-dimensional template (9) preparation method as described in any one of claims 1-4. One side is selected from each of the two sets of side sides of the surface to be tested of the bent sheet metal part (8) as the first positioning edge (3), and the side side corresponding to the two first positioning edges (3) on the process model surface (2) of the three-dimensional template (9) is selected as the second positioning edge (4). N2, the test surface of the bent sheet metal part (8) is fitted with the process model surface (2) of the corresponding three-dimensional template (9) so that the first positioning edge (3) and the corresponding second positioning edge (4) are aligned; N3, determine whether the shape feature data of the bent sheet metal part (8) and the three-dimensional template (9) are consistent. If they are consistent, proceed to the next step. If the shape feature data are inconsistent, the bent sheet metal part (8) is unqualified. N4. Measure the fit between the process model surface (2) of the three-dimensional template (9) and the test surface of the bent sheet metal part (8) at all bending locations. Determine whether the measured fit is within the detection range. If all fits are within the range, the bent sheet metal part (8) is qualified. If any fit is outside the range, the bent sheet metal part (8) is unqualified.

6. The method of using a three-dimensional template for bent sheet metal parts as described in claim 5, characterized in that: In step N4, the tool used to determine the fit between the test surface of the bent sheet metal part (8) and the process model surface (2) of the fitted three-dimensional template (9) is a feeler gauge.

7. The method of using a three-dimensional template for bent sheet metal parts as described in claim 6, characterized in that: The range of detection values ​​in step N4 is consistent with the tolerance value of the bending radius at the corresponding bending point of the bent sheet metal part (8).

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