Method and apparatus for forming plate flange based on convex magnet collector

Abstract

This invention relates to a method for forming sheet metal flanging based on a convex magnet collector. The method involves determining the parameters of a drive coil according to the sheet metal forming specifications, selecting the appropriate wire material and diameter, and winding the drive coil using a winding machine. The material and dimensional parameters of the convex magnet collector are then determined. The convex magnet collector is fabricated. After annealing pretreatment of the sheet metal to be formed, the center of the sheet metal is fixed using a mold. The convex magnet collector is arranged in the opposite direction to the flanging area of ​​the sheet metal to be formed, with the protrusion of the convex magnet aligned with the center of the flanging area. The drive coil is arranged at the bottom of the convex magnet collector and connected to a pulse power supply via a switch. Power is supplied to the drive coil, and the discharge time of the pulse power supply is controlled to perform flanging of the sheet metal to be formed. This invention improves the magnetic field distribution in the flanging area of ​​the sheet metal by using a convex magnet collector, thereby improving the flatness and uniformity of the formed flanging area and solving the problem of sheet metal buckling caused by uneven electromagnetic force distribution due to end effects.

Description

Technical Field

[0001] This invention belongs to the field of metal forming and manufacturing, and specifically relates to a method and apparatus for forming plate flanges based on a convex magnet. Background Technology

[0002] In aerospace, automotive, and other industries, flanging is a crucial process in the fabrication of lightweight alloys, directly impacting the forming accuracy of parts and the quality of subsequent assembly and welding. Lightweight alloys exhibit low formability at room temperature and are prone to springback and tearing, leading to bottlenecks in traditional flanging processes. Therefore, improving the flanging process to enhance the sheet metal forming performance of lightweight alloys has become a key research focus.

[0003] Traditional sheet metal flanging processes often encounter problems such as wrinkling and cracking in practical applications, especially for high-strength alloy sheets. During the flanging process, localized buckling and wrinkling often occur in stress concentration areas, leading to a decrease in part quality. To address this issue, Li Jianwei et al., in their paper "Research on Wrinkling Problems in Aluminum Alloy Sheet Flanging Process" published in *Forging Technology*, proposed a method to reduce wrinkling by optimizing process parameters. Through reasonable adjustments to the flanging height and blank holder force, they significantly reduced wrinkling during flanging and improved the flatness of the flanging process. However, this method is mainly applicable to aluminum alloy sheets with simple geometries; its improvement effect is limited for more complex and varied parts. [1] In their paper "Optimization Research on Plate Flanging Process Based on Dynamic Forming" published in *Mechanical Engineering Materials*, Wang Wei et al. addressed the cracking problem of high-strength alloy plates by introducing a dynamic loading method to enhance the plasticity of the material during the flanging process. This significantly reduced the probability of cracks during forming and improved the surface quality and precision of the formed parts. While this method further solves the problem of localized cracking during plate flanging through a dynamic deep drawing technique, its complex process and equipment requirements increase production costs, making it difficult to apply in large-scale industrial production. [2] .

[0004] In summary, current research on improvements to sheet metal flanging processes has addressed wrinkling and cracking issues encountered in actual forming to some extent. However, traditional processes still face significant limitations when dealing with workpieces with complex geometries and diverse materials. Furthermore, while technologies such as dynamic forming have improved the forming quality of sheet metal, the increased complexity of equipment and processes in real-world industrial environments restricts the widespread application of these technologies.

[0005] References:

[0006] [1]. Li Jianwei et al. Study on wrinkling problem in the flanging process of aluminum alloy plate [J]. Forging Technology, 2020, 55(6): 48-52.

[0007] [2]. Wang Wei et al. Research on optimization of plate flanging process based on dynamic forming [J]. Mechanical Engineering Materials, 2019, 47(3): 73-78. Summary of the Invention

[0008] The technical problem of this invention is that in the traditional plate flanging process, due to structural position, high-speed deformation and other reasons, the plate buckles due to uneven distribution of electromagnetic force during the flanging process, resulting in uneven plate flanging.

[0009] The purpose of this invention is to address the above-mentioned problems by providing a plate flanging forming method based on a convex magnet collector. A convex magnet collector is added between the driving coil and the flanging plate. The protrusion of the convex magnet collector is close to the middle of the plate flanging area. The convex magnet collector improves the magnetic field distribution in the plate flanging area and enhances the flatness of the plate flanging area after forming.

[0010] To achieve the above objectives, the technical solution provided by this invention is as follows:

[0011] The plate flanging forming method based on convex magnet collector includes the following steps:

[0012] Step 1: Determine the parameters of the drive coil according to the forming specifications of the sheet metal, select the corresponding wire and wire diameter, and wind the drive coil using a winding machine;

[0013] Step 2: Based on the parameters of the drive coil and the plate forming specifications obtained in Step 1, determine the material and dimensional parameters of the convex magnet collector;

[0014] Step 3: Based on the parameters obtained in Step 2, fabricate a convex magnet collector;

[0015] Step 4: After annealing pretreatment of the sheet to be formed, use a mold to fix the middle of the sheet to be formed;

[0016] Step 5: Arrange a convex magnet in the opposite direction of the flanged area of ​​the sheet to be formed, with the protrusion of the convex magnet aligned with the center of the flanged area of ​​the sheet to be formed.

[0017] Step 6: Arrange a drive coil at the bottom of the convex magnet collector, and connect the drive coil to the pulse power supply via a switch;

[0018] Step 7: Control the switch to supply power to the drive coil and control the discharge time of the pulse power supply to flip the edge of the workpiece to be formed;

[0019] Step 8: Determine whether the flanging effect of the sheet meets the flanging specifications. If it does, the process ends. Otherwise, proceed to step 7 to flanging the sheet again until the sheet meets the specifications.

[0020] Preferably, in step 1, a plate flanging simulation model including a drive coil and a plate is constructed using finite element software. A pulse current is applied to the drive coil in the plate flanging simulation model to simulate the flanging effect of the plate. The flanging effect of the plate is compared with the plate flanging forming effect. The parameters of the drive coil are adjusted to simulate the plate flanging until the plate forming specifications are reached, and the parameters of the drive coil are obtained.

[0021] Preferably, in step 2, a convex magnet is added to the plate flanging simulation model, and the plate flanging simulation model is used again to simulate the plate flanging. The width and height of the convex magnet are repeatedly adjusted so that the flatness and uniformity of the plate flanging area after the plate flanging is formed are the best, and the optimal dimensional parameters of the convex magnet are obtained.

[0022] Taking a circular plate with a radius of 50mm as an example, in the preferred embodiment, the height of the convex magnet is 0.8-1.2mm and the width is 5-7mm.

[0023] Preferably, the distance between the convex magnet and the plate to be formed is 0.2-0.4 mm.

[0024] Preferably, the distance between the convex magnet collector and the drive coil is 0.4-0.8 mm.

[0025] Preferably, in step 6, the pulse power supply is a capacitor power supply with a capacitance of 320μF and a voltage of 4.5kV.

[0026] The plate flanging device of the above-mentioned plate flanging forming method based on convex magnet collector includes a convex magnet collector, a drive coil, a pulse power supply and a pressing die; the drive coil is connected to the pulse power supply via a switch; the pressing die is used to fix the non-flanging area of ​​the plate to be formed.

[0027] Compared with the prior art, the beneficial effects of the present invention include:

[0028] 1) This invention adds a convex magnet collector between the drive coil and the flanged plate. The convex shape of the magnet collector reduces the distance between the collector and the center of the flanged area, thereby enhancing the electromagnetic field in the center of the flanged area. This effectively improves the magnetic field distribution in the flanged area, making the electromagnetic force more uniform. This effectively avoids flange buckling caused by uneven electromagnetic force due to end effects during the flanged process. Through this optimization, the flanged forming area is flatter, and the surface and dimensional accuracy of the formed plate are improved, which is beneficial for improving the quality of subsequent assembly and welding processes.

[0029] 2) This invention can adapt to the flanging requirements of different forming specifications of plates by adjusting the size and geometric parameters of the magnet collector without changing the drive coil, avoiding the trouble of frequent coil replacements and greatly improving the flexibility and production efficiency of plate flanging. At the same time, this flexibility makes the system more widely applicable, especially suitable for production lines with varying plate sizes.

[0030] 3) The convex magnet collector of the present invention not only has a relatively simple manufacturing process and lower cost, but also reduces the requirements of the drive coil in the plate flanging process to a certain extent, thereby reducing the overall manufacturing cost of the plate flanging device. In addition, the convex magnet collector can improve the eddy current distribution of the drive coil, reduce the electromagnetic force of the drive coil, withstand some of the electromagnetic force impact, significantly extend the service life of the drive coil, reduce equipment maintenance and replacement costs, make the electromagnetic flanging process more economical, and better suited for large-scale production.

[0031] 4) Due to the flexibility of configuring the convex magnet, this invention can meet the processing requirements of various plates, reduce downtime and equipment adjustment time caused by plate changes, and significantly shorten the flanging cycle. At the same time, by improving the uniformity of electromagnetic force distribution, the plate flanging process can be completed in one go, reducing rework and correction operations, further improving overall production efficiency, and facilitating the rapid production of large-volume, high-precision plate flanging. Attached Figure Description

[0032] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0033] Figure 1 This is a schematic diagram of the plate flanging forming method based on a convex magnet collector according to an embodiment of the present invention.

[0034] Figure 2 This is a schematic diagram of a plate flanging forming device based on a convex magnet collector according to an embodiment of the present invention.

[0035] Figure 3 This is a schematic diagram of a plate flange forming circuit based on a convex magnet collector according to an embodiment of the present invention.

[0036] Figure 4 This is a schematic diagram of a convex magnet collector device according to an embodiment of the present invention.

[0037] Figure 5 This is a schematic diagram of the simulation results of electromagnetic flanging of conventional plates according to an embodiment of the present invention.

[0038] Figure 6 This is a schematic diagram of the simulation results of plate flange based on convex magnet collector according to an embodiment of the present invention.

[0039] Explanation of reference numerals in the attached drawings: 1. Drive coil; 2. Convex magnet collector; 201. Protrusion; 3. Plate; 301. Flanged area; 4. Mold. Detailed Implementation

[0040] In this embodiment, by introducing a convex magnet between the drive coil and the forming plate, the electromagnetic force in the middle of the plate's flanged area is strengthened, the electromagnetic force at the end of the flanged area is reduced, the buckling phenomenon during the flanged process is improved, and the plate is finally flanged to the ideal angle.

[0041] like Figure 1 As shown, the plate flanging forming method based on a convex magnet collector includes the following steps:

[0042] Step 1: Determine the parameters of the drive coil according to the forming specifications of the sheet metal, select the corresponding wire and wire diameter, and wind the drive coil using a winding machine;

[0043] A simulation model of plate flanging, including a drive coil and a plate, was constructed using the finite element software COMSOL Multiphysics. A pulse current was applied to the drive coil in the plate flanging simulation model to simulate the flanging effect of the plate. The simulation was compared with the plate flanging forming effect. The parameters of the drive coil were adjusted to simulate plate flanging until the plate forming specifications were achieved, and the parameters of the drive coil were obtained.

[0044] Step 2: Based on the parameters of the drive coil and the plate forming specifications obtained in Step 1, determine the material and dimensional parameters of the convex magnet collector;

[0045] A convex magnet collector is added to the plate flanging simulation model, and the plate flanging simulation is performed again using the same model. A pulse current is applied to the drive coil to generate electromagnetic force in the plate. The final forming effect is analyzed, the model parameters are adjusted, and the uniformity of the final forming effect is compared to obtain the optimal geometric dimensions of the convex magnet collector and the distance between the convex magnet collector, the drive coil, and the plate.

[0046] Step 3: Based on the parameters obtained in Step 2, fabricate a convex magnet collector;

[0047] Step 4: After annealing pretreatment of the sheet to be formed, use a mold to fix the middle of the sheet to be formed;

[0048] Step 5: Arrange a convex magnet in the opposite direction of the flanged area of ​​the sheet to be formed, with the protrusion of the convex magnet aligned with the center of the flanged area of ​​the sheet to be formed.

[0049] Step 6: Arrange a drive coil at the bottom of the convex magnet collector, and connect the drive coil to the pulse power supply via a switch;

[0050] Step 7: Control the switch to supply power to the drive coil and control the discharge time of the pulse power supply to flip the edge of the workpiece to be formed;

[0051] Step 8: Determine whether the flanging effect of the sheet meets the flanging specifications. If it does, the process ends. Otherwise, proceed to step 7 to flanging the sheet again until the sheet meets the specifications.

[0052] During the plate flangeing process, the electromagnetic force F acting on the plate satisfies the following formula:

[0053]

[0054] In the formula, The induced eddy current density in the sheet metal. Let F be the magnetic flux density around the plate. The direction of the electromagnetic force F follows Lenz's law.

[0055] like Figure 2 As shown, the sheet metal flanging device of this embodiment includes a drive coil 1, a convex magnet collector 2, a sheet metal to be flanged 3, a mold 4, and a pulse power supply. The drive coil 1 provides an electromagnetic field and generates induced eddy currents in the sheet metal to be flanged; the convex magnet collector 2 improves the electromagnetic field distribution in the flanging area 301 of the sheet metal; the protrusion 201 strengthens the magnetic field strength in the center of the flanging area of ​​the sheet metal, such as... Figure 4 As shown; the plate to be flanged 3 is selected according to the actual situation; the mold 4 is used to control the range of the flanging area 301 of the plate, and the material can be selected according to the actual situation.

[0056] like Figure 3 As shown, the drive coil 1 is connected to a pulse power supply via an air switch. In this embodiment, the pulse power supply is a capacitor with a capacitance of 320μF and a voltage of 4.5kV. The capacitor's discharge circuit consists of a diode, a freewheeling resistor, a line inductance, and a line resistance. First, an external charging system charges the capacitor. After the capacitor is fully charged, the switch is turned off. The electrical energy stored in the capacitor is then transferred to the drive coil through the discharge circuit.

[0057] In traditional electromagnetic flanging processes, the buckling phenomenon in sheet metal differs from that in tubing. Because the portion of the sheet metal closer to the mold experiences stronger constraints, the flanged end tends to warp. To mitigate this, this invention employs a convex magnet to enhance the electromagnetic force in the center of the flanging area, thereby improving the electromagnetic force distribution within the flanging zone. The metal sheet is made of AA5083-O aluminum alloy, and the drive coil has 2×5 turns, with each turn having a cross-sectional area of ​​2mm×4mm. The outer diameter of the sheet metal to be formed is 100mm, and the inner diameter of the drive coil is 64mm. After introducing the convex magnet, the inner diameters of the sheet metal and the drive coil remain unchanged. The inner diameter of the convex magnet is 60mm, and its outer diameter is 90mm. The axes of the sheet metal to be flanged, the drive coil, and the convex magnet are collinear.

[0058] The capacitor is charged by an external charging system. After the capacitor is charged, the air switch is closed to load the energy stored in the capacitor onto the drive coil. In a short time, the drive coil will generate a strong pulsed magnetic field and induce eddy currents in the board. The convex magnet in the middle can reduce the distance between the magnet and the middle of the flanged area of ​​the board, and increase the magnetic flux density in the middle of the flanged area. By adjusting the magnetic flux density distribution in the flanged area of ​​the board, the electromagnetic force on the flanged area of ​​the board can be improved, effectively solving the buckling phenomenon of the flanged area of ​​the board.

[0059] This embodiment uses COMSOL Multiphysics software for simulation. The simulation results of the traditional plate flange method are as follows: Figure 5 As shown, the simulation results of the plate flange-flanging method based on the convex magnet collector of the present invention are as follows: Figure 6 As shown, Figure 5 and Figure 6 The size and direction of the arrow represent the magnitude and direction of the electromagnetic force. Figure 5 and Figure 6 It is evident that the buckling phenomenon during the plate flanging process of the present invention is significantly improved, the electromagnetic force is more evenly distributed during the plate flanging process, and the plate flanging area obtained by the present invention is flatter.

Claims

1. A method for forming the flange of a plate based on a convex magnet collector, characterized in that, The convex magnet is a ring shape with a slit. The top of the convex magnet has a protrusion. The cross-section of the convex magnet is convex. The protrusion of the convex magnet is close to the middle of the flanged area of ​​the plate to be formed. Under the action of the electromagnetic field of the driving coil, the convex magnet improves the magnetic field distribution of the flanged area of ​​the plate, improves the flatness of the flanged area after forming, and achieves uniform flanged plate. The plate flanging forming method includes the following steps: Step 1: Determine the parameters of the drive coil according to the forming specifications of the sheet metal, select the corresponding wire and wire diameter, and wind the drive coil using a winding machine; Step 2: Based on the parameters of the drive coil and the plate forming specifications obtained in Step 1, determine the material and dimensional parameters of the convex magnet collector; Step 3: Based on the parameters obtained in Step 2, fabricate a convex magnet collector; Step 4: After annealing pretreatment of the sheet to be formed, use a mold to fix the middle of the sheet to be formed; Step 5: Arrange a convex magnet in the opposite direction of the flanged area of ​​the sheet to be formed, with the protrusion of the convex magnet aligned with the center of the flanged area of ​​the sheet to be formed. Step 6: Arrange a drive coil at the bottom of the convex magnet collector, and connect the drive coil to the pulse power supply via a switch; Step 7: Control the switch to supply power to the drive coil and control the discharge time of the pulse power supply to flip the edge of the workpiece to be formed; Step 8: Determine whether the flanging effect of the sheet meets the flanging specifications. If it does, the process ends. Otherwise, proceed to step 7 to flanging the sheet again until the sheet meets the specifications.

2. The plate flanging forming method according to claim 1, characterized in that, In step 1, a plate flanging simulation model containing a drive coil and a plate is constructed using finite element software. A pulse current is applied to the drive coil in the plate flanging simulation model to simulate the flanging effect of the plate. The flanging effect of the plate is compared with the plate flanging forming effect. The parameters of the drive coil are adjusted to simulate the plate flanging until the plate forming specifications are reached, and the parameters of the drive coil are obtained.

3. The plate flanging forming method according to claim 2, characterized in that, In step 2, a convex magnet is added to the plate flanging simulation model, and the plate flanging simulation is performed again using the plate flanging simulation model. The width and height of the convex magnet are repeatedly adjusted to make the flatness and uniformity of the plate flanging area after the plate flanging is formed, so as to obtain the optimal dimensional parameters of the convex magnet.

4. The plate flanging forming method according to claim 1, characterized in that, The height of the protrusion of the convex magnet is 0.8-1.2mm.

5. The plate flanging forming method according to claim 1, characterized in that, The width of the protrusion of the convex magnet is 5-7mm.

6. The plate flanging forming method according to claim 1, characterized in that, The distance between the convex magnet and the plate to be formed is 0.2-0.4mm.

7. The plate flanging forming method according to claim 1, characterized in that, The distance between the convex magnet collector and the drive coil is 0.4-0.8mm.

8. The plate flanging forming method according to claim 1, characterized in that, In step 6, the pulse power supply is a capacitor power supply with a capacitance of 320 kJ / m³. The voltage of the capacitor power supply is 4.5kV.

9. The sheet metal flanging apparatus of the sheet metal flanging forming method according to any one of claims 1-8, characterized in that, The plate flanging device includes a convex magnet collector, a drive coil, a pulse power supply, and a pressing die; the drive coil is connected to the pulse power supply via a switch; the pressing die is used to fix the non-flanging area of ​​the plate to be formed.

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