Method for forming a z-section arcuate frame
By using a single-pass roll forming method, the problems of insufficient forming accuracy and low efficiency of Z-shaped frame were solved, achieving efficient and stable aluminum alloy Z-shaped frame forming and simplifying the springback compensation process.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHANGHAI AIRCRAFT MFG
- Filing Date
- 2026-04-10
- Publication Date
- 2026-06-09
AI Technical Summary
The forming process of Z-shaped fuselage frames has problems such as insufficient forming accuracy, low efficiency, long cycle and high cost. In particular, in the forming of aluminum alloy Z-shaped frames, cracks and wrinkles are prone to occur on the convex and concave bends, and the two-pass forming makes springback compensation difficult.
A one-step forming method is adopted, which uses at least three sets of rolls for roll-folding composite forming, including flat rolls, Z-shaped rolls and transition rolls. The mold is optimized through simulation and three-dimensional scanning, and the material deformation is gradually controlled to reduce springback and improve forming accuracy and efficiency.
It enables one-pass forming of Z-shaped cross-section arc frames, significantly shortening the manufacturing cycle, improving forming efficiency, reducing the risk of cracking and wrinkling, simplifying the springback compensation process, and improving forming quality.
Smart Images
Figure CN122164784A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of aircraft sheet metal manufacturing technology, and in particular to a method for forming a Z-shaped cross-section arc frame. Background Technology
[0002] The Z-shaped fuselage frame is a supporting component on the fuselage, a common main force-transmitting and load-bearing structure in aircraft fuselages. The fuselage frame and corner pieces are connected to the fuselage skin via metal fasteners, maintaining the shape of the fuselage panels and bearing external loads. It is characterized by its unique structure, large quantity, and high forming precision requirements. The Z-shaped fuselage frame features double flanges and an overall arc shape. Due to the complex structure of the Z-shaped fuselage frame, aluminum alloy Z-shaped frames are generally formed in two passes using a rubber bladder at room temperature. Typically, the convex bend is fitted to the skin, with theoretical shape precision requirements; generally, the concave bend is formed first, followed by the convex bend. During the forming process, as the rubber pressure increases, the suspended portion of the blank is bent along the forming die, forming the bend and gradually fitting together.
[0003] Aluminum alloy curved frames are often formed using rubber bladders. The concave bend is under biaxial tensile stress, causing the material to elongate and thin. When forming curved edges with a small bending radius, cracks may easily occur on the outer side of the R-zone. Conversely, the convex bend has a large radius of curvature and is under compressive stress, which may cause the material to shrink and wrinkle. Cracks may also occur in the R-zone because it mainly bears biaxial tensile and plane strain stress. Furthermore, due to the special characteristics of the Z-shaped cross-section, unlike the forming of simple L-shaped cross-section parts, the Z-shaped curved frame requires pressing the concave bend first and then the convex bend, requiring two-step forming. This results in insufficient forming accuracy of the Z-shaped curved frame part during the second flanging process, failing to meet the right angle requirements of the flanging area, increasing the difficulty of subsequent springback compensation, and causing problems such as long forming cycle, low efficiency, and increased labor costs.
[0004] Therefore, there is an urgent need to design a Z-shaped cross-section arc frame forming method to solve the above problems. Summary of the Invention
[0005] One objective of this invention is to provide a method for forming a Z-shaped cross-section arc frame, which produces a part that is formed in one pass, greatly shortening the overall manufacturing cycle and improving the forming efficiency of the part.
[0006] To achieve this objective, the present invention adopts the following technical solution: The method for forming a Z-shaped cross-section arc frame includes: S10: Obtain the initial blank by unfolding the arc-shaped frame; S20: The theoretical trajectory is formed based on the radius of curvature R of the arc-shaped frame described above; S30: At least three sets of rolls are arranged on the above theoretical trajectory. The first set of rolls is a flat roll, the last set of rolls is a Z-shaped roll that matches the cross-sectional shape of the arc frame, and at least one set of rolls in the middle is a transition roll. S40: Prepare molds based on digital models and conduct experiments to obtain initial parts for the field; S50: If there are no problems with the forming of the initial part on site, proceed to S60; if there are problems with the forming of the initial part on site, optimize the forming scheme of the mold until the forming is problem-free. S60: Use a 3D contour scanner to scan the formed part and compare it with the above-mentioned arc frame, and formulate a springback plan based on the comparison results; S70: Modify the above mold according to the above springback scheme, and repeat S60 until the springback value of the obtained part is within the tolerance range compared with the above arc frame.
[0007] As an optional solution, the side of the roll that contacts the initial billet is constructed as a Z-shaped side. The angle of the Z-shaped side bending inward is defined as the bending angle of the corresponding roll. The at least three sets of rolls that contact the initial billet in sequence are defined as the first roll, the second roll, up to the Nth roll. The bending angle of the Mth roll is A, and the bending angle of the (M+1)th roll is B. AB≤20°, 1≤M≤N-1.
[0008] As an alternative, the bending angle of the (N-1)th roll is C, and the bending angle of the Nth roll is D, where CD ≤ 10°.
[0009] As an optional solution, it also includes S51, which is between S50 and S60. S51: Analyze the initial part. If the initial part has defects, increase the number of the transition rollers and / or reduce the spacing between two adjacent sets of the rollers at the corresponding positions during the forming process.
[0010] As an alternative, the aforementioned defects include at least one of cracking or wrinkling caused by stress concentration.
[0011] As an optional solution, the following may also be included between S30 and S40: S31: Based on the above-mentioned initial billet, the above-mentioned theoretical trajectory and at least three sets of the above-mentioned rolls, a simulation is performed. The above-mentioned initial billet is rolled and formed into an initial product by at least three sets of the above-mentioned rolls in sequence and then springs back. S32: The initial product and the arc frame are compared differentially. Based on the differential comparison results, the initial product is first compensated for early springback, and then simulation is performed until the arc frame is obtained. In the above S40, the mold is prepared based on the digital model after the previous springback compensation.
[0012] As an optional solution, the aforementioned initial rebound compensation is divided into: If the initial product has a different radius of curvature than the arc frame, the theoretical trajectory is adjusted in the simulation to obtain a compensation trajectory, and then the simulation is repeated using the compensation trajectory. If the initial product exhibits localized edge rebound, adjust the angle of the rollers at the corresponding locations.
[0013] As an optional solution, in the above S50, the means of detecting molding problems include visual inspection, touch, and fluorescence penetration detection.
[0014] As an optional solution, optimizing the forming scheme of the above-mentioned mold includes at least one of the following: adjusting the position of the above-mentioned rolls, adjusting the forming surface of the above-mentioned rolls, and increasing the number of sets of the above-mentioned rolls.
[0015] As an alternative, at least three sets of the aforementioned rolls rotate, with the first roll drawing the initial billet into the next roll.
[0016] The beneficial effects of this invention are: The initial blank is formed by the above-mentioned Z-shaped cross-section arc frame forming method. For on-site manufacturing, it only takes one forming process, which saves process time compared to the traditional two-stage forming of rubber bladders. This effectively shortens the manufacturing time of each part and greatly improves the forming efficiency of the parts. For sheet metal forming, the aforementioned forming method employs a roller-folding composite forming process. This transforms the harsh plane strain-bi-tensile stress state of the traditional curved edge rubber bladder process into a bending-torsional composite stress state with a higher forming limit. This is more conducive to reducing the possibility of cracks during bending with small R-values. Understandably, the initial blank passes through a series of rollers, with each pair of rollers applying only a small portion of deformation, gradually bending it into the final shape. This progressive approach avoids the instantaneous application of enormous stress at a single location, as in existing technologies such as double-flanging, resulting in smoother and more uniform material deformation. This significantly reduces the risk of cracking due to localized stress exceeding the material's limits, especially at rounded corners, where the gradual forming by the rollers greatly reduces the risk of cracking. At convex bends, existing flanging schemes involve multi-material flanging, which leads to significant wrinkling, particularly at smaller R-values. However, the gradual forming method using rollers ensures a continuous process, with the material moving steadily under the precise guidance of the rollers. The roller design allows for precise control of material flow and extension in the width direction, effectively preventing compressive instability, i.e., wrinkling, caused by localized material accumulation. Similarly, at the concave bend, the existing flanging solution is to flanging with less material. When the flanging height of the concave bend is high, the risk of cracking is greater. However, by using the roll forming method, the material of the convex bend and the concave bend is evenly distributed by the roll, and the cracking situation will be significantly improved. For springback in manufactured parts, roll forming is a continuous and progressive forming process. As the billet passes through a series of rolls, it is gradually bent to the target shape. This continuous plastic deformation allows for a more uniform distribution and release of stress and strain within the material. The stress state across the entire deformation zone is relatively stable and consistent. Furthermore, roll forming can apply tangential tension while bending, causing the entire material cross-section to tend towards a tensile state. After springback unloading, the springback tendencies of the inner and outer layers cancel each other out, significantly reducing springback. Subsequent springback compensation schemes only need to consider the impact of a single forming operation. In contrast, the existing two-flanging scheme involves complex residual stresses within the material after the first flanging, resulting in springback immediately after the first flanging. The second flanging springback occurs on top of the first springback, increasing the instability of springback. For aluminum alloys, the conformity of the material to the second flanging die after the first flanging springback must also be considered, introducing more variable factors. Developing a springback solution requires step-by-step verification, analyzing which step results in the largest springback and determining which die to use for compensation. Therefore, for springback compensation, the gradual forming of the rolls can reduce the amount of springback and simplify the springback compensation approach. It is also easier to obtain standard parts in terms of process, saving a lot of time in both the initial process specification and the later on-site debugging. Attached Figure Description
[0017] Figure 1 This is a schematic diagram of the structure of the Z-shaped cross-section arc frame provided in an embodiment of the present invention; Figure 2 This is a flowchart of the Z-shaped cross-section arc frame forming method provided in the embodiments of the present invention; Figure 3 This is a schematic diagram of the forming of each roller and the arc-shaped frame provided in an embodiment of the present invention; Figure 4 These are schematic diagrams of the forming of each roll and the arc frame, as well as longitudinal cross-sectional views of each roll, provided in the embodiments of the present invention. Figure 5 is a longitudinal section view of the Z-shaped roller provided in an embodiment of the present invention and a schematic diagram of the bending angle of the Z-shaped roller.
[0018] In the picture: 10. Curved frame; 11. Concave bend; 12. Convex bend; 21. First roll; 22. Second roll; 23. Third roll; 24. Fourth roll; 25. Fifth roll; 26. Sixth roll. Detailed Implementation
[0019] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.
[0020] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.
[0021] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.
[0022] In the description of this embodiment, the terms "upper," "lower," "left," and "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.
[0023] like Figure 1 As shown, the original blank of the arc-shaped frame 10 is arc-shaped. A concave bend 11 is formed by flanging the inner side of the arc, and a convex bend 12 is formed by flanging the outer side of the arc. The concave bend 11 and the convex bend 12 are generally concentrically arranged. This embodiment provides a method for forming a Z-shaped cross-section arc-shaped frame. The arc-shaped frame 10 obtained by this forming method can be formed in one step, which greatly shortens the overall manufacturing cycle of the part and improves the forming efficiency of the part. On the other hand, the bending-torsional combined stress state has a higher forming limit, better forming effect, and more stable springback control, reducing the difficulty of subsequent springback compensation.
[0024] Specifically, such as Figure 1As shown, the method for forming the Z-shaped cross-section arc frame includes: S10: Obtain the initial blank by unfolding the arc frame 10; S20: The theoretical trajectory is formed based on the radius of curvature R of the arc frame 10; S30: At least three sets of rolls are arranged on the theoretical trajectory. The first set of rolls is a flat roll, the last set of rolls is a Z-shaped roll adapted to the cross-sectional shape of the arc frame 10, and at least one set of rolls in the middle is a transition roll. S40: Prepare molds based on digital models and conduct experiments to obtain initial parts for the field; S50: If there are no problems with the initial part forming on site, proceed to S60; if there are problems with the initial part forming on site, optimize the forming scheme of the mold until the forming is problem-free. S60: Use a 3D contour scanner to scan the formed part and compare it with the arc frame 10, and formulate a springback plan based on the comparison results; S70: Modify the mold according to the springback scheme, repeat S60, until the springback value of the obtained part is within the tolerance range compared with the arc frame 10.
[0025] Exemplary illustration, such as Figure 3 As shown, there are six sets of rollers. The first roller 21 is the first to contact the blank. The roller is a smooth cylindrical shape. The second roller 22, the third roller 23, the fourth roller 24 and the fifth roller 25 are transition rollers. The longitudinal cross-sectional shape of the outer periphery of the transition rollers gradually approaches the Z-shape of the cross-section of the arc frame 10. The sixth roller 26 is the last to contact the blank. The longitudinal cross-section of the outer periphery of the roller is consistent with the cross-sectional shape of the arc frame 10. The initial sheet is rolled and formed by the first roller 21 to the sixth roller 26 in sequence to obtain the initial product.
[0026] In other embodiments, the number of transition rollers can be adjusted according to the radius of curvature R of the Z-shaped arc frame 10 part and the forming accuracy requirements. The smaller the R value, the steeper the arc, and more transition rollers need to be selected to ensure that the trajectory gradually becomes uniform; the larger the R value, the gentler the arc, and the fewer the number of transition section rollers.
[0027] The initial blank is formed by the above-mentioned Z-shaped cross-section arc frame forming method. For on-site manufacturing, it only takes one forming process, which saves process time compared to the traditional two-stage forming of rubber bladders, effectively shortens the manufacturing time of each part, and greatly improves the forming efficiency of the parts.
[0028] For sheet metal forming, the aforementioned forming method employs a roller-folding composite forming process. This transforms the harsh plane strain-bi-tensile stress state of the traditional curved edge rubber bladder process into a bending-torsional composite stress state with a higher forming limit. This is more conducive to reducing the possibility of cracks during bending with small R-values. Understandably, the initial blank passes through a series of rollers, with each pair of rollers applying only a small portion of deformation, gradually bending it into the final shape. This progressive approach avoids the instantaneous application of enormous stress at a single location, as in existing technologies such as double-flanging, resulting in smoother and more uniform material deformation. This significantly reduces the risk of cracking due to localized stress exceeding the material's limits, especially at rounded corners, where the gradual forming by the rollers greatly reduces the risk of cracking. At the convex bend 12 position, existing flanging schemes involve multi-material flanging, which leads to particularly noticeable wrinkling when the R-value is smaller. However, the gradual forming method using rollers ensures a continuous process, with the material moving steadily under the precise guidance of the rollers. The roller design precisely controls the flow and extension of the material in the width direction, effectively avoiding compressive instability, i.e., wrinkling, caused by localized material accumulation. Similarly, at the concave bend 11 position, the existing flanging solution is a small material flanging. When the flanging height of the concave bend 11 is high, the risk of cracking is greater. However, by using the roll forming method, the material of the convex bend 12 and the concave bend 11 is evenly distributed by the roll, and the cracking situation will be significantly improved.
[0029] For springback in manufactured parts, roll forming is a continuous and progressive forming process. As the billet passes through a series of rolls, it is gradually bent to the target shape. This continuous plastic deformation allows for a more uniform distribution and release of stress and strain within the material. The stress state across the entire deformation zone is relatively stable and consistent. Furthermore, roll forming can apply tangential tension while bending, causing the entire material cross-section to tend towards a tensile state. After springback unloading, the springback tendencies of the inner and outer layers cancel each other out, significantly reducing springback. Subsequent springback compensation schemes only need to consider the impact of a single forming operation. In contrast, the existing two-flanging scheme involves complex residual stresses within the material after the first flanging, resulting in springback immediately after the first flanging. The second flanging springback occurs on top of the first springback, increasing the instability of springback. For aluminum alloys, the conformity of the material to the second flanging die after the first flanging springback must also be considered, introducing more variable factors. Developing a springback solution requires step-by-step verification, analyzing which step results in the largest springback and determining which die to use for compensation. Therefore, for springback compensation, the gradual forming of the rolls can reduce the amount of springback and simplify the springback compensation approach. It is also easier to obtain standard parts in terms of process, saving a lot of time in both the initial process specification and the later on-site debugging.
[0030] like Figure 5As shown, the side of the roll that contacts the initial billet is constructed as a Z-shaped side. The angle at which the Z-shaped side bends inward is defined as the bending angle of the corresponding roll, that is... Figure 5 In the definition of α, at least three sets of rolls that sequentially contact the initial billet are the first roll 21, the second roll 22, up to the Nth roll. The bending angle of the Mth roll is denoted as A, and the bending angle of the (M+1)th roll is denoted as B, where AB ≤ 20° and 1 ≤ M ≤ N-1. The smaller the change in bending angle between two adjacent rolls, the smaller the change in forming, the more uniform the deformation, the lower the possibility of cracking and wrinkling, and the corresponding reduction in springback.
[0031] Optionally, the bending angle of the (N-1)th roll is C, and the bending angle of the Nth roll is D, where CD ≤ 10°. Taking six sets of rolls as an example (that is, in this embodiment, N = 6), as follows... Figure 4 As shown, the bending angle of the first roll 21 is 180°, the bending angle of the second roll 22 is 170°, the bending angle of the third roll 23 is 150°, the bending angle of the fourth roll 24 is 130°, the bending angle of the fifth roll 25 is 110°, and the bending angle of the sixth roll 26 is 90°. The bending angle of the last two rolls changes by 10°, which is smaller than the others. Since it is closer to the end of the forming process, the change in bending angle is appropriately reduced to make the final forming step more stable.
[0032] Optionally, the following may also be included between S30 and S40: S31: Simulation is performed based on the initial billet, theoretical trajectory and at least three sets of rolls. The initial billet is rolled into shape by at least three sets of rolls in sequence and then springs back to obtain the initial product. S32: The initial product is compared with the arc frame 10 by differential comparison. Based on the differential comparison results, the initial product is first compensated for the initial rebound, and then simulation is performed until the arc frame 10 is obtained. In S40, the mold is prepared based on the digital model after springback compensation. In other words, before entering the on-site stage, the forming process is simulated and springback is generated in the simulation software through finite element analysis, and then springback compensation is performed in the software, which can greatly reduce the workload of on-site springback compensation.
[0033] Optionally, the forming method further includes S51, which is between S50 and S60. S51: Analyze the initial part. If the initial part has defects, increase the number of transition rolls and / or reduce the spacing between two sets of adjacent rolls at the corresponding position during the forming process. Increasing the number of transition rolls makes the stress change more balanced overall, while reducing the spacing between the two sets of rolls at the corresponding position is a targeted smoothing optimization for the defect.
[0034] Optionally, the initial rebound compensation is divided into: If the initial product has a different radius of curvature than the arc frame 10, the theoretical trajectory is adjusted in the simulation to obtain the compensation trajectory, and then the simulation is repeated with the compensation trajectory. If the initial product exhibits localized springback at the flange, adjust the roll angle at the corresponding location (this angle is also the bending angle mentioned above). It should be noted that different springback scenarios can be considered holistically, or two methods may be applied simultaneously in the same simulation. Process engineers can adjust parameters based on experience and compare the simulation results to previous ones to see if the springback performance has improved (improvement could mean a smaller springback value, less product distortion, or a curvature closer to the curvature of the arc frame 10). Then, based on this simulation version, further optimization or a new springback plan can be developed.
[0035] Understandably, the Z-shaped cross-section arc frame forming method belongs to the early manufacturing process stage, and on-site manufacturing is still required.
[0036] It is understandable that while the on-site and simulated working conditions are ideally consistent, the actual situation does not perfectly match the simulation. For example, factors such as the coefficient of friction and sheet metal parameters can cause discrepancies between the on-site springback results and the simulation results, necessitating springback compensation. Generally, forming problems are less frequent if the initial simulation adjustments are adequate. If forming problems do occur, the rectification plan can refer to the optimization methods used in the early stages of the process, such as adjusting the position of the rolls, adjusting the forming surface of the rolls, and increasing the number of roll sets.
[0037] For the springback rectification plan, the previous springback optimization plan can also be referenced. At this time, if it is necessary to change the R value, the roller can be set on the mold base and the direction can be adjusted.
[0038] Optionally, in S50, the methods for detecting forming problems include visual inspection, manual inspection, and fluorescent penetrant testing. Among them, fluorescent penetrant testing can detect hidden defects in the part, preventing the part from leaving the factory with defects that lead to non-conformity.
[0039] In this embodiment, at least three sets of rollers rotate, with the first roller pulling the initial billet into the next roller. When applied to a die, this method ensures the billet is pulled forward by the rollers, and a guide is placed between two rollers to prevent the billet from deviating. In the initial simulation, the roller mill can be fixed, the billet remains stationary, and the first roller 21 to the Nth roller sequentially roll the billet. Of course, the simulation can also be performed in the same way as in the actual situation, and this is not limited here.
[0040] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art will be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.
Claims
1. A method for forming a Z-shaped cross-section arc frame, characterized in that, include: S10: Obtain the initial blank by unfolding the arc frame (10); S20: The theoretical trajectory is formed based on the radius of curvature R of the arc frame (10); S30: At least three sets of rolls are arranged on the theoretical trajectory. The first set of rolls is a flat roll, the last set of rolls is a Z-shaped roll adapted to the cross-sectional shape of the arc frame (10), and at least one set of rolls in the middle is a transition roll. S40: Prepare molds based on digital models and conduct experiments to obtain initial parts for the field; S50: If there are no problems with the initial part forming on site, proceed to S60; If there are problems with the initial part forming on site, optimize the forming scheme of the mold until the forming is problem-free; S60: Use a three-dimensional contour scanner to scan the formed part and compare it with the arc frame (10), and formulate a springback plan based on the comparison results; S70: Modify the mold according to the springback scheme, and repeat S60 until the springback value of the obtained part is within the tolerance range compared with the arc frame (10).
2. The Z-shaped cross-section arc frame forming method according to claim 1, characterized in that, The side of the roll that contacts the initial billet is constructed as a Z-shaped side. The angle at which the Z-shaped side bends inward is defined as the bending angle of the corresponding roll. The at least three sets of rolls that sequentially contact the initial billet are defined as the first roll (21), the second roll (22), up to the Nth roll. The bending angle of the Mth roll is A, and the bending angle of the (M+1)th roll is B. AB≤20°, 1≤M≤N-1.
3. The Z-shaped cross-section arc frame forming method according to claim 2, characterized in that, The bending angle of the (N-1)th roll is C, and the bending angle of the Nth roll is D, where CD ≤ 10°.
4. The Z-shaped cross-section arc frame forming method according to claim 3, characterized in that, It also includes S51, which is between S50 and S60. S51: Analyze the initial part, and if the initial part has defects, increase the number of the transition rolls and / or reduce the spacing between two adjacent sets of the rolls at corresponding positions during the forming process.
5. The Z-shaped cross-section arc frame forming method according to claim 4, characterized in that, The defect includes at least one of cracking or wrinkling caused by stress concentration.
6. The method for forming a Z-shaped cross-section arc frame according to any one of claims 1-5, characterized in that, Between S30 and S40, there is also: S31: Based on the initial billet, the theoretical trajectory, and at least three sets of the rolling mills, a simulation is performed. The initial billet is rolled and formed into an initial product by at least three sets of the rolling mills in sequence and then springs back. S32: The initial product is compared with the arc frame (10) by difference. Based on the difference comparison result, the initial product is first compensated for early rebound, and then simulation is performed until the arc frame (10) is obtained. In step S40, a mold is prepared based on the digital model after the springback compensation.
7. The Z-shaped cross-section arc frame forming method according to claim 6, characterized in that, The initial rebound compensation is divided into: If the initial product has a different radius of curvature than the arc frame (10), the theoretical trajectory is adjusted in the simulation to obtain a compensation trajectory, and then the simulation is repeated using the compensation trajectory. If the initial product exhibits localized edge rebound, the angle of the roller at the corresponding location shall be corrected.
8. The method for forming a Z-shaped cross-section arc frame according to any one of claims 1-5, characterized in that, In S50, the means of detecting molding problems include visual inspection, touch, and fluorescence penetration detection.
9. The method for forming a Z-shaped cross-section arc frame according to any one of claims 1-5, characterized in that, Optimizing the forming scheme of the mold includes at least one of the following: adjusting the position of the rolls, adjusting the forming surface of the rolls, and increasing the number of sets of rolls.
10. The method for forming a Z-shaped cross-section arc frame according to any one of claims 1-5, characterized in that, At least three sets of the rolls rotate, with the first roll pulling the initial billet into the next roll.