A follow-up material supporting process for bending forming of aluminum curtain wall plate

Abstract

This invention relates to a follow-up material support process for bending and forming aluminum curtain wall panels, belonging to the field of metal sheet processing technology. By dividing the material support area into a first near-bending zone, a second intermediate support zone, and a third free-end follow-up zone, and adopting differentiated material support methods such as avoidance guidance, same-speed surface support, and rolling traction, and combining the intermediate zone and the free-end zone with the same follow-up base to achieve self-driven synchronous follow-up of the sheet material, this invention effectively solves the problems of relative slippage, geometric interference, excessive local pressure, and unstable support caused by sheet material displacement and flipping in the prior art. It significantly reduces surface defects such as scratches, indentations, and fogging marks on the visible surface of the aluminum curtain wall panel. At the same time, the consistency of bending angle and springback stability are improved through smooth load transfer and continuous surface support, thereby achieving reliable processing under deep bending and high-flanging conditions while ensuring high appearance quality.

Description

Technical Field

[0001] This invention belongs to the field of metal sheet processing technology, specifically relating to a follow-up material support process for bending and forming aluminum curtain wall panels. Background Technology

[0002] In the field of aluminum curtain wall panel processing, in order to meet the requirements of installation connection and structural reinforcement, aluminum curtain wall panels need to be bent along a predetermined bending line on a bending machine to form flanges and folds. Aluminum curtain wall panels with PVDF fluorocarbon spraying or anodizing surface treatment maintain a protective film covering the visible surface during production and complete the bending process. The existing process is to configure a material support frame, material support arm, and roller table in front of the bending machine to support the free end of the panel, and to add felt pads, rubber pads, and plastic sheets to the material contact area to reduce hard contact. Bending positioning is achieved through back gauge and lateral limit.

[0003] However, in actual production, during the bending process of PVDF fluorocarbon coated and anodized aluminum curtain wall panels, the downward pressure of the upper die causes the sheet to rotate around the bending line. The free end of the sheet deflects downwards under gravity. As the bending stroke progresses, the change in the contact state between the sheet and the die causes displacement along the feed direction and subsequent tilting. The fixed support frame and the fixed roller table cannot synchronously follow this displacement, resulting in continuous sliding friction between the back of the sheet and the support frame. The protective film wrinkles and attached particles create hard-point dragging during this friction, resulting in bright lines, fine scratches, and fogging marks on the high-gloss surface. Roller-type support frames bear loads through line and point contact, leading to concentrated load distribution. This leads to increased local contact pressure, causing indentations on the coating surface. The cushion material undergoes compressive deformation under pressure, resulting in changes in support height and fluctuations in the torque on the sheet at the die. This, in turn, causes poor consistency in bending angles and fluctuations in springback. In deep bending and high flanging conditions, the material support structure near the bending line is located near the flanging sweep path, and geometric interference causes collisions and defects on the visible surface. Reducing the support near the bending area to avoid interference exacerbates the downward deflection of the free end, increasing the risk of accidental collision between the sheet and the machine tool metal parts. These contradictions make it difficult for the existing single material support method to simultaneously meet the comprehensive requirements of low slippage, low pressure, avoidance, and support stability. Summary of the Invention

[0004] To address the aforementioned problems in the prior art, this invention provides a follow-up material support process for bending aluminum curtain wall panels, which solves the problems of scratches, indentations, and bending angle fluctuations caused by relative slippage and interference of the fixed material support due to panel displacement and flipping during aluminum curtain wall panel bending.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] A follow-up material support process for bending and forming aluminum curtain wall panels includes the following steps:

[0007] S1: Preparation before bending: Keep the visible surface of the aluminum curtain wall panel covered with protective film, deburr the bending edges, and clean the back of the panel and the area in contact with the support to remove dust and metal shavings.

[0008] S2: Using the bending line as a reference, the support range of the material is continuously divided into areas along the direction pointing to the free end of the sheet. The area near the bending line is defined as the first near bending zone. The area in the middle of the sheet after the first near bending zone is defined as the second intermediate support zone. The area at the free end of the sheet is defined as the third free end follow-up zone. The guide material is avoided in the first near bending zone, low-pressure contact is maintained and a flanging sweep gap is reserved. The same speed surface support material is set in the second intermediate support zone. Soft support belts are used to provide surface support for the back of the sheet in the support section and to achieve the same direction of movement as the sheet. Rolling traction material is set in the third free end follow-up zone. Rollers with elastic layer are used to support the free end and lateral limit is set.

[0009] S3: Place the sheet metal on the support of the first near-bending area, the second intermediate support area, and the third free end follower area, align the bending line with the mold, and complete the material stop positioning and lateral limit. Adjust the height of the first near-bending area, the second intermediate support area, and the third free end follower area so that the second intermediate support area bears the main load, the third free end follower area suppresses downward deflection, and the first near-bending area maintains guidance and maintains clearance.

[0010] S4: Execute the bending stroke. The sheet material is displaced along the feed direction, pushing the follower base to move, so that the second intermediate support area and the third free end follower area move synchronously. During the bending process, the first near-bending area continuously maintains the clearance, while the second intermediate support area maintains continuous support to complete the smooth transfer of load.

[0011] S5: After bending and forming, remove the sheet material, check the visible defects in the material contact area and bending area, and verify the bending angle and dimensions.

[0012] As a further embodiment of the present invention, in step S2, the material support of the second intermediate support area and the third free end follower area are arranged on the same follower base.

[0013] As a further aspect of the present invention, in step S2, segmented material support units are arranged in front of the bending machine along the feed direction, and a clearance space is preset for each segmented material support unit before bending.

[0014] As a further aspect of the present invention, in step S1, the bending sequence and the maximum flange height of each bend are determined according to the bending type of the aluminum curtain wall panel, and the bending line position is marked.

[0015] As a further aspect of the present invention, during steps S1 to S5, the visible surface of the aluminum curtain wall panel is continuously kept covered by a protective film until the bending inspection is completed.

[0016] As a further aspect of the present invention, in step S4, when the flanging sweep trajectory approaches the first near-bending zone, the support of the first near-bending zone on the sheet material is released and an avoidance gap is formed, and the second intermediate support zone continues to provide continuous support for the sheet material.

[0017] As a further embodiment of the present invention, in step S4, the soft support belt of the second intermediate support area is driven to run in the same direction as the back of the board in the support section.

[0018] As a further aspect of the present invention, in step S4, a roller with an elastic layer is used to support the free end of the sheet metal in the third free end follower zone in a rolling contact manner, and lateral limiting is applied to the free end to suppress lateral movement.

[0019] As a further aspect of the present invention, in step S4, as the bending stroke progresses, the load supporting the sheet material is smoothly transferred from the third free end follower zone to the second intermediate support zone, and the second intermediate support zone maintains continuous surface support to keep the sheet material's posture stable.

[0020] As a further embodiment of the present invention, in step S2, the material support surface that contacts the back of the sheet is set as a non-metallic rolling contact surface or a support surface covered with an elastic layer.

[0021] The beneficial effects of this invention are as follows: By dividing the material support area into a first near-bending area, a second intermediate support area, and a third free-end follow-up area, and adopting differentiated material support methods such as avoidance guidance, same-speed surface support, and rolling traction respectively, and combining the intermediate area and the free-end area to be set on the same follow-up base to achieve self-driven synchronous follow-up of the plate, this invention effectively solves the problems of relative slippage, geometric interference, excessive local pressure, and unstable support caused by plate displacement and flipping in the prior art. It significantly reduces surface defects such as scratches, indentations, and fogging marks on the visible surface of aluminum curtain wall panels. At the same time, the consistency of bending angle and springback stability are improved through smooth load transfer and continuous surface support, thereby achieving reliable processing under deep bending and high-flanging conditions while ensuring high appearance quality. Attached Figure Description

[0022] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to the accompanying drawings.

[0023] Figure 1 This is a flow chart of the follow-up material support process for bending and forming aluminum curtain wall panels according to the present invention.

[0024] Figure 2 This is a process flow diagram of step S2 of the present invention;

[0025] Figure 3 This is a process flow diagram of step S3 of the present invention;

[0026] Figure 4 This is a process flow diagram for step S4 of the present invention. Detailed Implementation

[0027] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided.

[0028] Please see Figures 1-4 As shown, this embodiment provides a follow-up material support process for bending and forming aluminum curtain wall panels, including the following steps:

[0029] S1: Preparation before bending: Keep the visible surface of the aluminum curtain wall panel covered with protective film, deburr the bending edges, and clean the back of the panel and the area in contact with the support to remove dust and metal shavings.

[0030] S2: Using the bending line as a reference, the support range of the material is continuously divided into areas along the direction pointing to the free end of the sheet. The area near the bending line is defined as the first near bending zone. The area in the middle of the sheet after the first near bending zone is defined as the second intermediate support zone. The area at the free end of the sheet is defined as the third free end follow-up zone. The guide material is avoided in the first near bending zone, low-pressure contact is maintained and a flanging sweep gap is reserved. The same speed surface support material is set in the second intermediate support zone. Soft support belts are used to provide surface support for the back of the sheet in the support section and to achieve the same direction of movement as the sheet. Rolling traction material is set in the third free end follow-up zone. Rollers with elastic layer are used to support the free end and lateral limit is set.

[0031] In addition, in step S2, the material support of the second intermediate support area and the third free end follower area are arranged on the same follower base. The follower base is installed on the ground through a low-friction linear guide rail. A one-way overrunning clutch or damping buffer is provided between the base and the frame. When the material feeding force is greater than the set threshold (e.g., 50N), the base unlocks and follows. When the material moves in the reverse direction during the bending return stroke, the base is locked by a reset spring to prevent the material from being dragged in the reverse direction.

[0032] S3: Place the sheet metal on the support of the first near-bending area, the second intermediate support area, and the third free end follower area, align the bending line with the mold, and complete the material stop positioning and lateral limit. Adjust the height of the first near-bending area, the second intermediate support area, and the third free end follower area so that the second intermediate support area bears the main load, the third free end follower area suppresses downward deflection, and the first near-bending area maintains guidance and maintains clearance.

[0033] S4: Follow-up bending and avoidance: During the bending stroke, the sheet metal is displaced along the feed direction, pushing the follow-up base to move, so that the second intermediate support area and the third free end follow-up area move synchronously; the support belt runs in the same direction as the sheet metal in the support section to reduce relative slippage; during the bending process, the first near-bending area maintains an avoidance gap to prevent the flange from interfering with or rubbing against the support material, while the second intermediate support area maintains continuous support to complete the smooth transfer of load;

[0034] In step S4, the first near-bending zone is equipped with an elastic lifting or swing arm type avoidance mechanism. When the flanging sweep trajectory approaches the first near-bending zone, the mechanism actively releases the support of the sheet material and forms an avoidance gap, while the second intermediate support zone continues to provide continuous support for the sheet material. After bending is completed, the avoidance mechanism automatically resets to the initial guide position. The avoidance mechanism here includes an elastic lifting block or a swing arm type roller bracket. In the initial stage of bending, the avoidance mechanism maintains low-pressure guide contact with the back of the sheet material under the action of the elastic element. When bending proceeds to the point where the flanging sweep trajectory approaches the area, the flanging presses down on the elastic lifting block or pushes the swing arm to deflect, so that the area automatically forms an avoidance gap. After bending is completed, the avoidance mechanism automatically returns to the initial guide position under the action of the elastic reset element.

[0035] In addition, in step S4, as the bending stroke progresses, the sheet metal support load is smoothly transferred from the third free end follower zone to the second intermediate support zone. The mechanical mechanism is that the second intermediate support zone provides stable reaction force through the surface support of the soft support belt, and its support arm remains basically unchanged during the bending process, thereby avoiding sudden torque changes. The soft support belt of the second intermediate support zone is driven by a servo motor and is linked with the feed speed of the bending machine through a speed sensor to achieve the same speed as the back of the sheet metal, which significantly reduces relative slippage and unstable drag force.

[0036] S5: After bending and forming, remove the sheet material, check the visible defects in the material contact area and bending area, and verify the bending angle and dimensions.

[0037] Furthermore, to verify the technical effects of the present invention, PVDF fluorocarbon coated aluminum curtain wall panels of the same specifications, for example, 2000mm×1000mm×2mm in size and 80mm in flange height, were used for bending comparison experiments. The present invention's process and the existing technology (fixed support frame and felt pad) were used for processing, with 50 pieces processed in each case. The comparison results showed that the bending angle qualification rate (within ±0.5°) of the present invention's process reached 98%, significantly higher than the 84% of the existing technology; the surface defect rate of visible surface scratches and indentations of the present invention's process was only 2%, far lower than the 18% of the existing technology; at the same time, the average processing time per piece of the present invention's process was shortened by approximately 17% compared to the existing technology. The above experimental data indicate that the present invention, through comprehensive technical means such as zoned differentiated support, same-speed surface support, and self-driven synchronous follow-up, has achieved significantly better results than the existing technology in improving bending accuracy, reducing surface defect rate, and increasing processing efficiency.

[0038] To address the issues of scratches, indentations, and bending angle fluctuations caused by relative slippage and interference of the fixed support material due to panel displacement and flipping during aluminum curtain wall panel bending in existing technologies, this embodiment decomposes the complex motion of the panel during bending—displacement along the feed direction, flipping and lifting around the bending line, and downward deflection due to gravity at the free end—into controllable support targets. Firstly, in step S1, by retaining the visible protective film, deburring, and cleaning the back contact area, the probability of hard particles and burrs forming bright lines and fine scratches during contact friction is reduced from the source. Then, in step S2, the support range from the bending line to the free end is continuously divided into a first near-bending zone, a second intermediate support zone, and a third free-end follow-up zone. The first near-bending zone only provides low-pressure guidance and reserves a flanging sweep gap; its purpose is not to bear load but to prevent loss of control near the bending line. Interference is avoided to prevent geometric rubbing caused by the traditional near-bending material support being near the edge sweeping path; the second intermediate support zone uses a soft support belt for surface support and runs in the same direction as the sheet, using surface contact and the same speed to solve two key defects at the same time: first, changing the load from point or line contact of the roller to surface support to significantly reduce local contact pressure, thereby suppressing coating indentation; second, making the support section move in the same direction as the sheet, so that the continuous sliding friction between the back of the sheet and the support material changes to near-zero relative slippage, thereby reducing bright lines or fogging marks caused by protective film wrinkles and dragging of attached particles; the third free end follow-up zone uses elastic layer rollers to support the free end and set lateral limits, reducing follow-up resistance by rolling, while using an elastic layer to buffer contact pressure and reduce hard contact marks, and lateral limits to suppress edge rubbing caused by lateral movement of the free end;

[0039] Furthermore, in step S3, the second intermediate support area bears the main load through height calibration, the third follower area suppresses deflection, and the first near-bending area only guides and maintains clearance, placing the main load-bearing area in the least likely to interfere and the area with the best low slippage. In step S4, the displacement of the sheet material along the feed direction during bending pushes the follower base to move, so that the second intermediate support area and the third free end follower area follow the sheet material. This eliminates the root cause of the fixed support material not keeping up with the displacement from a kinematic perspective, and maintains the clearance of the first near-bending area throughout the bending process. The second intermediate support area continuously supports and completes the smooth transfer of load, thereby avoiding poor bending angle consistency and springback fluctuations caused by sudden changes in support height or torque, and systematically solving scratches, indentations, and angle fluctuations.

[0040] It should be noted that the reason for dividing the area into three zones—the first near-bending zone, the second intermediate support zone, and the third free-end follow-up zone—and processing them in this manner in steps S2-S4 is because, in bending scenarios of aluminum curtain wall panels, especially PVDF fluorocarbon coated or anodized high-appearance components, a single support method cannot simultaneously meet the requirements of low slippage, low pressure, and stable support. The area near the bending line, i.e., the first near-bending zone, is subject to edge sweeping during bending. The biggest concern here is geometric interference and rubbing. Therefore, the design goal is to guide without obstructing movement. Low-pressure light contact is allowed to suppress proximal sagging or attitude deviation, while a flanging sweep gap must be reserved, and this gap must be maintained continuously during bending to ensure no collision. The second intermediate support zone is far from the flanging sweep, and the space allows for more stable load-bearing. Therefore, it is most suitable for undertaking the triple objectives of main load, low pressure, and low slippage. Soft support surface is used to reduce pressure, and relative slippage is minimized for sheet metal movement in the same direction. Furthermore, because it bears the main load, it can stabilize the torque on the sheet metal at the die, directly serving the consistency of bending angle; while the third free end follower zone deflects under the action of gravity. The bending radius is the largest and displacement is the most significant. Insufficient support will exacerbate the downward deflection and increase the risk of the plate surface accidentally hitting the machine tool's metal parts. However, using a high-friction fixed surface support at the free end will amplify drag friction. Therefore, the design goal here is to achieve low-resistance follow-up, suppress downward deflection, and prevent lateral movement. Using rollers with an elastic layer can transform the friction mechanism into rolling when following the displacement. The elastic layer reduces pressure and hardening, and lateral limiting solves the risk of edge rubbing caused by lateral deviation at the free end. Furthermore, step S2 divides the support range continuously instead of using discrete point support to avoid local suspension during the bending process. The impact of sudden load drop; the height calibration in step S3 is to artificially set a stable load distribution before the bending begins, so that the bending moment is not led by the compression deformation of the support; step S4 allows the sheet material displacement to drive the follower base to move, which changes the follower control from complex external control to more reliable sheet material self-driven follower, and through the continuous avoidance of the first near bending zone and the continuous support of the second intermediate support zone, the coordination of continuous support throughout the bending process to local avoidance and then to smooth load transfer is achieved. This is the systematic starting point for solving the problem of sag when not supported and easy interference or dragging when supported.

[0041] Since both the second intermediate support area and the third free-end follower area need to move along the feed direction with the sheet metal, if they are installed and follower separately, in scenarios involving long plates, large sizes, and deep bends, the same sheet metal will be constrained by two asynchronous support points. The third follower area may be pushed away by the sheet metal first, while the second intermediate support area lags behind, causing relative slippage of the back of the sheet metal in the second support area. Conversely, if the second support area moves first and the third area lags behind, the free end will experience additional drag or posture twisting at the roller. This asynchrony will lead to three types of consequences: first, the relative slippage returns, increasing the risk of abrasion; second, the distribution of support reaction force changes abruptly, the load transfer is no longer smooth, and the bending moment fluctuation leads to poor angle consistency; third, the sheet metal undergoes slight twisting, making lateral restraint more difficult. Easily scratched, resulting in edge scratches or positioning errors. To avoid this problem, in one embodiment, in step S2, the material support of the second intermediate support area and the third free end follower area are arranged on the same follower base, and the follower base is movable along the feed direction. Essentially, the two support units that need to follow are turned into a whole follower support system, eliminating the relative displacement degree of freedom between the two, so that the second and third sections will necessarily move synchronously when the sheet is pushed to follow, thereby cutting off the root cause of relative slippage, torsion and sudden load change. The reason why the same base must be used is that, since the above is to achieve sheet self-driven follow, the most reliable way to achieve this is to shorten the motion chain on which the follow depends to one unit, avoiding the following difference caused by multiple actuators and multiple friction pairs.

[0042] Following the above embodiments, under the near-bending avoidance approach, different products will exhibit different maximum flange heights, different bending angles, and different bending sequences. Especially in deep bending or high flange conditions, the flange sweeping space increases significantly. Furthermore, the sheet metal does not only rotate around the bending line during the bending process but also shifts along the feed direction. If there is only a fixed or single-segment support structure, even if there is no interference at a certain moment, it may still enter the sweeping path and cause collisions as the bending angle continues to increase. On the other hand, if the near-end support is lowered as a whole to avoid interference, it will exacerbate the downward deflection of the free end and bring the risk of accidental collisions. Therefore, in one embodiment, in step S2, a segmented support unit is arranged in front of the bending machine along the feed direction, and a support unit is provided before bending. Each material support unit has a pre-set clearance space to prevent interference with the already formed flange when the bending angle increases. Here, a segmented structure is used to separate the area that may interfere from the area that must bear the load. When a certain segment needs to avoid interference, it can be achieved by reserving the structural position or space to avoid collision, without sacrificing the support of the free end of the subsequent segment. This maintains the goal of continuous support and zero interference throughout the entire stroke. The reason for using pre-setting before bending is that interference is not a random event, but a deterministic result determined by the flange geometry and movement trajectory. Pre-setting the clearance space is equivalent to eliminating the risk of interference in advance, avoiding sudden load changes and surface collisions caused by temporary removal or movement during bending, and ensuring that the process is repeatable and can be mass-produced.

[0043] Because operators must clearly define the bending sequence, the maximum flange height of each bend, and the accurate position of the bending line before bending, in the production of curtain wall panels with multiple bends, if the bending sequence is not properly selected, such as bending a high flange first and then performing another bend, the formed flange will prematurely enter the sweeping space of the material support / mold, resulting in a significant increase in the probability of interference. If there is an error in the bending line calibration, the division of the first near-bending area, the second intermediate support area, and the third free end follow-up area will be misaligned as a whole: the near-bending area may encroach on the main support area or vice versa, causing avoidance failure or insufficient support, and then returning to the scratches and angle fluctuations mentioned in the background art. To avoid this problem, in one embodiment, in step S1, the bending sequence and the position of each bend are determined according to the bending type of the aluminum curtain wall panel. The maximum flange height of the bend is determined, and the position of the bend line is marked. In step S1, the bending sequence is determined according to the bending type, the maximum flange height is marked, and the position of the bend line is marked. This is equivalent to changing the partitioning and avoidance of the first near-bending area, the second intermediate support area, and the third free end follower area from experience-based adjustment to preset based on working condition parameters. This ensures that the support of the first near-bending area, the second intermediate support area, and the third free end follower area is not an isolated structure, but a motion matching system established around the position of the bend line, the flange movement trajectory, and the product process sequence. Only by first determining the sequence and the maximum flange height can we reasonably decide in S2 which section needs to be avoided, how much to avoid, and where the main support should fall, thereby ensuring that the follower and load transfer in subsequent S3-S4 are stable and controllable.

[0044] Even though the relative slippage and contact pressure have been significantly reduced in the preceding text through the use of surface support at the same speed, elastic rollers, and low-pressure guides, there are still low-probability but high-impact surface risks in the mass production of high-gloss PVDF or anodized surface parts. For example, residual dust on the back, wrinkles at the edge of the protective film, and micro-contamination on the surface of the elastic layer supporting the material may all form minor scratches or haze marks in a certain batch. Once the protective film on the visible surface is removed or damaged during bending, any minor contact abnormality will directly affect the coating body, leading to irreversible appearance defects. To address this, in one embodiment, during steps S1 to S5, the aluminum curtain wall panel is continuously kept in a state of flux. The visible surface is covered by a protective film until the bending inspection is completed. During steps S1 to S5, the visible surface is continuously covered by the protective film until the inspection is completed. The solution is to isolate the visible surface from potential hard spots or friction risks. Even if local abnormal contact occurs, the protective film will be damaged first rather than the coating itself. The reason for continuing to cover it until the inspection is that surface defects are not limited to the moment of bending and pressing, but may also occur in the stages of material loading and positioning, follow-up displacement, unloading and handling. Using the protective film as a protective layer throughout the entire process can form a superimposed protection with the reduction of slippage or pressure, and meet the engineering requirements of the consistency of the appearance of the curtain wall panel.

[0045] Furthermore, while maintaining a clearance in the first near-bending zone is proposed, under extreme conditions such as large bending angles, high flange heights, large plate thicknesses, and springback causing trajectory deviations, the distance between the flange sweep trajectory and the material support structure will dynamically change with the stroke. Simply relying on a fixed pre-reserved clearance may result in a boundary state: initially there is a gap, but as the flange lifts and the plate displacement overlaps, the sweep trajectory gradually approaches, and eventually, slight rubbing may still occur. On the other hand, if the clearance is reserved too large from the beginning, it will cause insufficient support in the near-bending zone during the initial bending stage, leading to unstable plate posture near the mold and indirectly affecting angle consistency. Therefore, in one embodiment, in step S4... When the flanging sweep trajectory approaches the first near-bending zone, the support of the first near-bending zone on the sheet material is released, and an avoidance gap is formed. The second intermediate support zone continues to provide continuous support to the sheet material, switching the first near-bending zone from an early guiding or anti-sagging state to a later completely avoidance state. This achieves avoidance control that changes with the stroke, while ensuring that the sheet material does not lose support. This balances initial stability and zero interference in the later stages. The reason for this design is that the risk of flanging sweep is a dynamic risk that increases with the bending angle. Only by designing the near-bending zone as an avoidance mode that can be released from support can we ensure that there is no interference or collision in the later stages of deep bending without sacrificing initial guidance.

[0046] In actual production, there is an engineering problem: the unidirectional movement of the support belt can be either passively driven by the friction of the sheet metal or actively driven. When the sheet metal is heavy or the friction coefficient on the back side is unstable (e.g., due to dust, differences in friction of the protective film, or aging of the support belt surface), passive driving may result in slippage or speed deviation, making stable unidirectional movement impossible. As a result, relative slippage still exists, the risk of scratches increases, and the support belt generates an unstable drag force on the sheet metal, which may be superimposed on the bending moment, causing angle fluctuations. In one embodiment, in step S4, the soft support belt in the second intermediate support area is driven to move in the support section against the back of the sheet metal. The same-direction operation reduces the relative slippage between the back of the panel and the support, making the same-direction movement controllable instead of just possible. The speed and direction of the support can stably match the displacement trend of the panel, significantly reducing relative slippage and unstable dragging, thereby further reducing the risk of scratches and angle fluctuations. The driving mechanism needs to be emphasized here because the displacement and speed of the curtain wall panel bending are affected by factors such as the contact state of the mold, panel thickness, and coating friction. It is difficult to maintain the same speed in mass production by relying solely on passive friction transmission. Only active driving can engineer and lock this key variable, ensuring that the core effect can be reproduced under different batches and different panel lengths.

[0047] It is worth mentioning that in the third free end follower zone, the goal is to suppress downward deflection and follow the movement. However, the force and motion of the free end are the most complex: it is both the position where the cantilever end is most prone to downward deflection and the position where lateral movement and posture swaying are most likely to occur during bending. If ordinary metal rollers are used to support the free end, the point or line contact pressure is high, which can easily leave marks on the coating. If no lateral limit is provided, the free end may drift laterally during feeding and flipping, causing the plate edge to rub against the material support, lateral limit, or machine tool components, and even causing a slight offset of the bending line relative to the die position, which ultimately reflects a decrease in the consistency of angle or dimensions. In one embodiment, in step S4, a roller covered with an elastic layer is used to support the free end of the sheet metal in the third free end follower zone in a rolling contact manner, and lateral restraint is applied to the free end to suppress lateral movement. Here, it is explicitly stated that a roller covered with an elastic layer is used to support the free end in a rolling contact manner and to apply lateral restraint to the free end. The elastic layer reduces local contact pressure and hard imprint risk by increasing the effective contact area and providing a smooth buffer; the rolling contact reduces follower resistance and reduces shear friction that drags the sheet metal; the lateral restraint brings the lateral degree of freedom of the free end to a controllable range, preventing lateral movement from causing edge rubbing and positioning drift.

[0048] Furthermore, the above text emphasizes that the second intermediate support area maintains continuous support and completes the smooth transfer of load during the bending process. However, in actual production, how the load is transferred directly determines the angle stability and surface risk: as the upper die presses down, the sheet metal flips and lifts around the bending line, and the contact normal force between the free end follower area and the sheet metal gradually changes, even from a large support to a light touch or detachment; if the second support area does not bear the main load in advance or the support is discontinuous during this process, there will be a sudden loss of load in the free end area, leading to an instantaneous change in the sheet metal posture, and then an instantaneous collision between the sheet metal surface and the support or machine tool. At the same time, the sudden change in torque at the die causes fluctuations in the bending angle and springback. This instantaneous change is especially obvious under the conditions of long plates, thin plates, and high flanges. In this regard, in one embodiment, in step S4, as the bending stroke progresses... This design allows the load on the sheet metal to be smoothly transferred from the third free-end follower zone to the second intermediate support zone, with the second intermediate support zone maintaining continuous surface support to ensure the stability of the sheet metal's posture. This design is essentially an engineering of the load path based on the previous design. The main task of the third free-end follower zone gradually fades from anti-bending and traction follower, while the second intermediate support zone always acts as the main load-bearing platform, taking over and stabilizing the reaction force distribution to avoid torque fluctuations and posture jumps. This design is because the consistency of the bending angle essentially depends on the stability of the torque near the bending line, and the torque is affected by the reaction force and lever arm of the far-end support. Only by making the load transfer a smooth and predictable process can the torque change during the bending process be controlled and continuous, thereby achieving a stable angle and a lower probability of surface defects in mass production.

[0049] In the processing of highly sensitive surface parts such as coatings or oxide films, the contact pair material and contact morphology are still the underlying factors that determine indentation or scratches. Even if the relative slippage is very small, indentation may still occur when the load is concentrated if the contact surface is too hard, the contact area is too small, or the supporting surface is a hard metal edge. Even if the contact pressure is reduced, if the supporting surface is metal and there are embedded microparticles, it is easier to form hard spot drag. In this regard, in one embodiment, in step S2, the material support surface that contacts the back of the sheet is set as a non-metallic rolling contact surface or a support surface with an elastic layer to reduce the contact pressure and reduce the risk of hard contact scratches. Non-metallic rolling contact reduces friction and scratching tendency, and the elastic layer reduces the pressure peak by deforming and distributing the load, while being less likely to form hard spots for microparticles.

[0050] Working principle and usage process of this invention:

[0051] The complex motion of the sheet metal during bending is decomposed into controllable support targets. The material support area is divided into a first near-bending zone, a second intermediate support zone, and a third free-end follower zone along the feed direction. Differentiated designs are adopted for each zone, including avoidance guide material support, same-speed surface support material support, and rolling traction material support. The near-bending zone maintains an avoidance gap to avoid flanging interference. The intermediate zone reduces slippage and indentation through the surface contact and same-direction movement of the soft support belt. The free-end zone is supported by rollers with elastic layer and suppresses downward deflection. At the same time, the intermediate zone and the free-end zone are arranged on the same follower base to achieve self-driven synchronous follower of the sheet metal, thereby systematically solving the problems of scratches, indentations, and bending angle fluctuations caused by fixed material support.

[0052] In the specific process, preparations are first made before bending, keeping the visible surface covered with a protective film and cleaning the back side; then, three zones are delineated based on the bending line and corresponding material support structures are set up. After positioning the sheet metal, the height of each zone is adjusted so that the middle zone bears the main load; during bending, the sheet metal pushes the follower base along the feed direction, so that the middle zone and the free end zone move synchronously. The near bending zone maintains a continuous clearance and the load is smoothly transferred by the continuous support of the middle zone; after forming, the sheet metal is removed and surface defects and bending accuracy are checked. The visible surface is covered with a protective film throughout the process until the inspection is completed.

[0053] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A follow-up material support process for bending and forming aluminum curtain wall panels, characterized in that, Includes the following steps: S1: Preparation before bending: Keep the visible surface of the aluminum curtain wall panel covered with protective film, deburr the bending edges, and clean the back of the panel and the area in contact with the support to remove dust and metal shavings. S2: Using the bending line as a reference, continuously divide the material support area along the direction pointing to the free end of the sheet metal into regions. Define the area near the bending line as the first near-bending zone, the area in the middle of the sheet metal after the first near-bending zone as the second intermediate support zone, and the area at the free end of the sheet metal as the third free end follow-up zone. In the first near-bending zone, avoid guiding the material support, maintain low-pressure contact, and reserve a flanging sweeping gap. A surface support material is set up in the second intermediate support area with the same speed. A soft support belt is used to support the back of the board in the support section and to move in the same direction as the board. A rolling traction material is set up in the third free end follow-up area. Rollers with elastic layer are used to support the free end and are set with lateral limit. S3: Place the sheet metal on the support of the first near-bending area, the second intermediate support area, and the third free end follower area, align the bending line with the mold, and complete the material stop positioning and lateral limit. Adjust the height of the first near-bending area, the second intermediate support area, and the third free end follower area so that the second intermediate support area bears the main load, the third free end follower area suppresses downward deflection, and the first near-bending area maintains guidance and maintains clearance. S4: Execute the bending stroke. The sheet material is displaced along the feed direction, pushing the follower base to move, so that the second intermediate support area and the third free end follower area move synchronously. During the bending process, the first near-bending area continuously maintains the clearance, while the second intermediate support area maintains continuous support to complete the smooth transfer of load. S5: After bending and forming, remove the sheet material, check the visible defects in the material contact area and bending area, and verify the bending angle and dimensions. In step S2, segmented material support units are arranged in front of the bending machine along the feed direction, and a clearance space is preset for each segmented material support unit before bending; In step S4, when the flanging sweep trajectory approaches the first near-bending area, the support of the first near-bending area on the sheet material is released and a clearance gap is formed, and the second intermediate support area continues to provide continuous support to the sheet material. In step S4, as the bending stroke progresses, the load supporting the sheet material is smoothly transferred from the third free end follower zone to the second intermediate support zone, and the second intermediate support zone maintains continuous surface support to keep the sheet material's posture stable.

2. The following material support process for bending and forming aluminum curtain wall panels according to claim 1, characterized in that, In step S2, the material support of the second intermediate support area and the third free end follower area are arranged on the same follower base.

3. The following material support process for bending and forming aluminum curtain wall panels according to claim 1, characterized in that, In step S1, the bending sequence and the maximum flange height of each bend are determined according to the bending type of the aluminum curtain wall panel, and the bending line position is marked.

4. The following material support process for bending and forming aluminum curtain wall panels according to claim 1, characterized in that, During steps S1 to S5, the visible surface of the aluminum curtain wall panel is kept covered by the protective film until the bending inspection is completed.

5. The following material support process for bending and forming aluminum curtain wall panels according to claim 1, characterized in that, In step S4, the soft support belt of the second intermediate support area is driven to run in the same direction as the back of the board in the support section.

6. The following material support process for bending and forming aluminum curtain wall panels according to claim 1, characterized in that, In step S4, a roller with an elastic layer is used to support the free end of the sheet metal in the third free end follower zone in a rolling contact manner, and the free end is laterally limited to suppress lateral movement.

7. The following material support process for bending and forming aluminum curtain wall panels according to claim 1, characterized in that, In step S2, the material support surface that contacts the back of the sheet is set as a non-metallic rolling contact surface or a support surface with an elastic layer.

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