Electromagnetic pulse forming device and method for local characteristics of skin part

Abstract

The invention discloses a skin part local characteristic electromagnetic pulse forming device and method, and relates to the technical field of metal plate part plastic forming manufacturing, the skin part local characteristic electromagnetic pulse forming device comprises an upper pressing beam, a mechanical arm, an electromagnetic coil and a multi-point stretch-forming die, and the multi-point stretch-forming die is installed on a fixed bottom plate; the two ends of the skin plate are tightly attached to the top face of the multi-point stretch-forming die after being clamped and tensioned through a jaw of a skin stretch-forming machine; the shape of the top surface of the multi-point stretch-forming die is adjustable; one end of the mechanical arm is fixed to the upper pressing beam, an electromagnetic coil is installed at the other end of the mechanical arm and used for conducting electromagnetic forming on the skin plate, and the position of the upper pressing beam can be adjusted. A multi-point stretch-forming die and electromagnetic forming are combined, and meanwhile, the high-efficiency characteristic of the multi-point forming technology and the high-precision characteristic of the electromagnetic incremental forming technology are utilized, so that high-efficiency and high-precision digital forming of the complex three-dimensional curved-surface-shaped part can be realized.

Description

Technical Field

[0001] This invention relates to the field of plastic forming manufacturing technology for sheet metal parts, and in particular to an electromagnetic pulse forming apparatus and forming method for local features of skin parts. Background Technology

[0002] Aircraft skin is primarily used on the fuselage and wings. Its outer surface directly contacts airflow and has aerodynamic and strength requirements, making it a crucial component in shaping the aircraft's aerodynamic shape. Its manufacturing demands not only accuracy in shape and mechanical performance indicators but also stringent requirements for surface quality. Therefore, it requires accurate shape, smooth streamlines, and a surface free of scratches, abrasions, coarse grains, and other defects. Currently, large aircraft skins are trending towards larger dimensions, thinner curved surfaces, variable thickness, and integral structures. Especially due to the increasingly complex aerodynamic layouts of aircraft, numerous aircraft skin parts with large macroscopic dimensions and small local features are being designed. Traditional skin stretching and forming methods cannot achieve one-time forming; instead, segmented stamping is used, followed by manual hammering and welding, severely impacting the fatigue performance of the components and the aircraft's air intake efficiency. Therefore, the domestic aerospace manufacturing industry urgently needs to develop and apply new and practical forming processes for aerospace components.

[0003] Electromagnetic forming, a typical representative of special energy field forming technology, operates on the principle of generating a strong magnetic field by passing a pulsed current through a drive coil. This induces eddy currents in the metal workpiece, forming a Lorentz force that drives the material to undergo high-speed plastic deformation. This technology features non-contact forming, simple equipment and tooling, and clean, efficient operation. It significantly improves material ductility, reduces springback and wrinkling, and lowers equipment costs. Its advantage lies in the fact that the electromagnetic force can be controlled sequentially to achieve repulsive or attractive loading, and can be flexibly adjusted in time and space, making it particularly suitable for forming complex components from lightweight alloys such as aluminum, magnesium, and titanium, as well as high-strength steel.

[0004] However, the current manufacturing process for large-sized skins with small features suffers from excessive manual intervention, making it impossible to form them in one go. A new forming method needs to be designed to solve this problem. Summary of the Invention

[0005] The purpose of this invention is to provide an electromagnetic pulse forming device and forming method for local features of skin parts, so as to solve the problems existing in the prior art. It adopts a combination of multi-point stretching mold and electromagnetic forming, and at the same time utilizes the high efficiency of multi-point forming technology and the high precision of electromagnetic progressive forming technology to realize high-efficiency and high-precision digital forming of complex three-dimensional curved surface parts.

[0006] To achieve the above objectives, the present invention provides the following solution: The present invention provides an electromagnetic pulse forming device for local features of skin parts, including an upper pressure beam, a robotic arm, an electromagnetic coil, and a multi-point stretching mold. The multi-point stretching mold is mounted on a fixed base plate. Both ends of the skin sheet are clamped and stretched by the jaws of a stretching machine and then pressed tightly against the top surface of the multi-point stretching mold. The shape of the top surface of the multi-point stretching mold is adjustable. One end of the robotic arm is fixed to the upper pressure beam, and the other end of the robotic arm is equipped with the electromagnetic coil. The electromagnetic coil is used for electromagnetic forming of the skin sheet. The position of the upper pressure beam is adjustable.

[0007] In one embodiment, the multi-point forming die is composed of multiple regularly arranged basic bodies distributed in a matrix, and the shape of the multi-point forming die is adjusted by a computer control system.

[0008] In one embodiment, the basic body includes a plurality of basic body punches, each basic body punch including a punch body, a ball head and a hydraulic cylinder adjusting rod, the hydraulic cylinder adjusting rod being mounted on the fixed base plate, the top telescopic end of the hydraulic cylinder adjusting rod being sequentially connected to the ball head and the punch body, and the skin sheet being tightly attached to the punch body.

[0009] In one embodiment, the computer control system controls the hydraulic cylinder adjusting rod to adjust the height of each of the basic punches according to the basic punch height data calculated by the software, so as to construct the multi-point drawing die of the required shape.

[0010] In one embodiment, the skin sheet is placed on the multi-point stretching mold, and an elastic pad is placed between the skin sheet and the multi-point stretching mold.

[0011] In one embodiment, guide rails are provided on both sides of the fixed base plate, and the upper pressure beam can move along the guide rails to the upper part of the processing area of ​​the skin sheet material under the drive of the driving device.

[0012] In one embodiment, the upper pressure beam is connected to the hydraulic cylinder, the hydraulic cylinder is connected to the hydraulic cylinder seat, and the hydraulic cylinder seat is equipped with a driving device for driving the hydraulic cylinder seat to move along the direction of the guide rail.

[0013] In one embodiment, the electromagnetic coil is connected to a pulsed current system.

[0014] In one embodiment, the number of robotic arms is greater than or equal to two, and each robotic arm is equipped with an electromagnetic coil at its bottom end. The electromagnetic coil at the bottom end of each robotic arm is used to perform local feature forming on different positions of the skin sheet.

[0015] The present invention also provides an electromagnetic pulse forming method for local features of skin parts, applied to the aforementioned electromagnetic pulse forming apparatus for local features of skin parts, comprising the following steps:

[0016] Step 1: Multi-point forming die adjustment: The computer control system adjusts the height of each basic punch according to the basic punch height data calculated by the software to construct the multi-point forming die of the required shape.

[0017] Step 2, fixing the skin panel: Place the skin panel on the adjusted multi-point stretching mold, and place an elastic pad between the skin panel and the multi-point stretching mold. The jaws of the stretching machine clamp the skin panel and stretch it according to the adjusted multi-point stretching mold, so that the skin panel is tightly attached to the multi-point stretching mold.

[0018] Step 3, Skin sheet stretching and forming: According to the geometry of the skin part, the skin sheet is stretched and loaded through the jaws of the stretching machine, then bent using the working surface of the multi-point stretching die, and then stretched again;

[0019] Step 4, Upper pressure beam descends: Driven by the hydraulic cylinder seat with the drive device, the upper pressure beam moves along the guide rail to above the processing area of ​​the skin sheet. The upper pressure beam moves downward under the action of the hydraulic cylinder and cooperates with the action of the robotic arm to move the electromagnetic coil installed on the robotic arm to the local feature to be formed area of ​​the skin sheet.

[0020] Step 5, Local Electromagnetic Forming with Electromagnetic Coil: When the electromagnetic coil moves to the local feature area to be formed of the skin part, a pulse current is passed through to drive the electromagnetic coil to generate a strong magnetic field, inducing eddy currents in the skin sheet and forming Lorentz force, driving the material at the local feature of the skin sheet to achieve high-speed plastic deformation.

[0021] The present invention achieves the following beneficial technical effects compared to the prior art:

[0022] This invention discloses an electromagnetic pulse forming apparatus and method for local features of skinned parts. The apparatus includes an upper pressure beam, a robotic arm, an electromagnetic coil, and a multi-point stretching mold. The multi-point stretching mold is mounted on a fixed base plate. Both ends of the skinned sheet are clamped and stretched by the jaws of a stretching machine and then pressed tightly against the top surface of the multi-point stretching mold. The shape of the top surface of the multi-point stretching mold is adjustable. One end of the robotic arm is fixed to the upper pressure beam, and the other end of the robotic arm is equipped with an electromagnetic coil. The electromagnetic coil is used for electromagnetic forming of the skinned sheet. The position of the upper pressure beam is adjustable. In this invention, a combination of multi-point stretching mold and electromagnetic forming is used. By utilizing the high efficiency of multi-point forming technology and the high precision of electromagnetic progressive forming technology, high-efficiency and high-precision digital forming of complex three-dimensional curved surface parts can be achieved. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 A schematic diagram of the overall structure of the electromagnetic pulse forming device for local features of skin parts;

[0025] Figure 2 This is a structural diagram of the basic punch.

[0026] Figure 3 This is a schematic diagram of the multi-point stretch forming die adjustment process;

[0027] Figure 4 This is a rendering of the forming effect of a local feature of a skin part;

[0028] Figure 5 This is a forming drawing of a skin part with local features;

[0029] Among them, 1. Upper pressure beam; 2. Hydraulic cylinder; 3. Hydraulic cylinder seat; 4. Guide rail; 5. Robotic arm; 6. Electromagnetic coil; 7. Mold jaw of the forming machine; 8. Elastic pad; 9. Skin sheet material; 10. Multi-point forming die; 10-1. Basic punch; 10-2. Ball head; 10-3. Punch body; 10-4. Hydraulic cylinder adjusting rod. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] The purpose of this invention is to provide an electromagnetic pulse forming device and forming method for local features of skin parts, so as to solve the problems existing in the prior art. It adopts a combination of multi-point stretching mold and electromagnetic forming, and at the same time utilizes the high efficiency of multi-point forming technology and the high precision of electromagnetic progressive forming technology to realize high-efficiency and high-precision digital forming of complex three-dimensional curved surface parts.

[0032] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0033] like Figures 1-5As shown, the present invention provides an electromagnetic pulse forming device for local features of skin parts, including an upper pressure beam 1, a robotic arm 5, an electromagnetic coil 6, and a multi-point stretching mold 10. The multi-point stretching mold 10 is mounted on a fixed base plate. The two ends of the skin sheet 9 are clamped and pulled by the jaws 7 of the stretching machine and then pressed tightly against the top surface of the multi-point stretching mold 10. The shape of the top surface of the multi-point stretching mold 10 is adjustable. One end of the robotic arm 5 is fixed to the upper pressure beam 1, and the other end of the robotic arm 5 is equipped with an electromagnetic coil 6. The electromagnetic coil 6 is used for electromagnetic forming of the skin sheet 9. The position of the upper pressure beam 1 is adjustable.

[0034] In one embodiment, the multi-point forming die 10 includes multiple regularly arranged basic bodies. These basic bodies are distributed in a matrix to form the multi-point forming die 10. The shape of the multi-point forming die 10 is adjusted by software and a computer control system. Specifically, each basic body includes multiple basic punches 10-1. Each basic punch 10-1 includes a punch body 10-3, a ball head 10-2, and a hydraulic cylinder adjusting rod 10-4. The hydraulic cylinder adjusting rod 10-4 is mounted on a fixed base plate. The top telescopic end of the hydraulic cylinder adjusting rod 10-4 is sequentially connected to the ball head 10-2 and the punch body 10-3. The skin sheet 9 is tightly attached to the punch body 10-3. The computer control system controls the hydraulic cylinder adjusting rod 10-4 to adjust the height of each basic punch 10-1 according to the height data of the basic punches 10-1 calculated by the software, so as to construct the multi-point forming die 10 of the required shape.

[0035] In one embodiment, the skin sheet 9 is placed on the adjusted multi-point stretching mold 10, and an elastic pad 8 is placed between the skin sheet 9 and the multi-point stretching mold 10.

[0036] In one embodiment, guide rails 4 are provided on both sides of the fixed base plate. The upper pressure beam 1 can move along the guide rails 4 to the upper area above the processing area of ​​the skin sheet 9 under the drive of the drive device. The upper pressure beam 1 is connected to the upper pressure beam 1 cylinder 2, and the upper pressure beam 1 cylinder 2 is connected to the cylinder seat 3. The cylinder seat 3 is equipped with a drive device, which is used to drive the cylinder seat 3 to move along the X-axis direction on the guide rail 4.

[0037] In one embodiment, the electromagnetic coil 6 is connected to a pulsed current system.

[0038] In one embodiment, the number of robotic arms 5 is greater than or equal to two, and each robotic arm 5 is equipped with an electromagnetic coil 6 at its bottom end. The electromagnetic coil 6 at the bottom end of each robotic arm 5 is used to perform local feature forming on different positions of the skin sheet 9.

[0039] This invention addresses the problem that excessive manual intervention and the inability to form large-sized, small-feature skin parts in a single process during manufacturing. It proposes an electromagnetic pulse forming method and apparatus for localized features of skin parts. This method fully utilizes the high efficiency of converting electromagnetic forming magnetic field energy into mechanical energy and the flexibility of multi-point stretching molds (10) in replacing solid molds. During the stretching process of the skin part, an electromagnetic field is applied to localized features of the skin part. By inducing eddy currents and generating Lorentz forces in the metal workpiece, the material is driven to achieve high-speed plastic deformation of the localized features of the skin part, thereby forming the skin part with localized features.

[0040] 1. This invention employs a combination of multi-point forming die 10 and electromagnetic forming, utilizing the high efficiency of multi-point forming technology and the high precision of electromagnetic progressive forming technology to achieve high-efficiency and high-precision digital forming of complex three-dimensional curved surface parts. In traditional production processes, due to part springback, local features on the skin require repeated manual striking for correction, and the die also needs springback compensation and repair. In this invention, the height of individual basic punches 10-1 in the multi-point forming die 10 can be digitally controlled, and the local features of the forming die can be adjusted in real time according to the springback deformation of the part to achieve springback compensation. Simultaneously, combined with the repeated striking of electromagnetic forming, progressive and precise forming of local features of the skin part is achieved. Furthermore, the elastic pad 8 on the multi-point forming die 10 and the electromagnetic force applied to the local features of the skin part generate high-frequency vibrations, transforming the elastic deformation state inside the skin sheet 9 into a plastic deformation state, thereby eliminating springback. This invention can save the cost and time spent on complex processes such as mold debugging and mold repair during the manufacturing of skin sheet 9, significantly shortening the development cycle of new products. It can also avoid a lot of manual intervention through the gradual coordination of electromagnetic forming process and multi-point stretching mold 10.

[0041] 2. This invention employs a novel progressive forming method combining skin stretching and electromagnetic forming, which integrates traditional sheet metal stretching with electromagnetic pulse progressive forming technology to achieve precise manufacturing of large, thin-walled curved parts. By combining the two, the skin sheet 9 is first initially formed using a stretching process, and then precise local forming and correction are performed using electromagnetic pulse forming technology. Further processing of the stretched skin sheet 9 is achieved by progressively discharging a small coil along a set trajectory, making the sheet more closely conform to the mold surface and improving forming accuracy. This reduces manual intervention in the traditional sheet metal stretching process.

[0042] 3. In this technical solution, the electromagnetic coil 6 is integrated on the upper pressure beam 1 by the robotic arm 5. It can move in a wide range in the X and Z directions with the upper pressure beam 1. At the same time, the robotic arm 5 can also adjust its position in the processing area of ​​the skin sheet 9, realizing the spatiotemporal matching of the electromagnetic coil 6 with multiple degrees of freedom during the stretching process of the skin sheet 9.

[0043] An electromagnetic pulse forming method for local features of a skinned part includes the following steps:

[0044] Step 1: Shaping of the Multi-Point Forming Die 10: The multi-point forming die 10 is composed of a regularly arranged matrix of basic shapes. The surface adjustment of the multi-point forming die 10 is completed through software and a computer control system. The basic shapes include multiple basic punches 10-1. The basic punches 10-1 are the most critical components of the multi-point forming die 10. Depending on the application, a multi-point forming die may have thousands or even tens of thousands of basic punches 10-1. See... Figure 2 The basic punch 10-1 typically consists of three parts: punch body 10-3, ball head 10-2, and adjusting rod. The height of the basic punch 10-1 is adjusted via the adjusting rod's shaping mechanism to construct the mold surface. During the shaping process of the punch body 10-3, the basic punches 10-1 guide each other. Mounted on a fixed base plate, the basic punches 10-1 press against each other during the sheet metal forming process, causing the multi-point forming mold 10 to form a single unit. The computer control system can control the adjusting mechanism to adjust the height of each basic punch 10-1 based on the height data calculated by the software, constructing the multi-point forming mold 10 of the required shape. The shaping process is as follows... Figure 3 As shown.

[0045] Step 2, Fixing the Skin Panel 9: See Figure 4 Place the skin sheet 9 on the adjusted multi-point stretching mold 10, and place an elastic pad 8 between the skin sheet 9 and the multi-point stretching mold 10. The stretching machine jaws 7 clamp the skin sheet 9 and stretch it according to the adjusted multi-point stretching mold 10, so that the skin sheet 9 is tightly attached to the multi-point stretching mold 10.

[0046] Step 3: Stretching and forming of skin sheet 9: See Figure 4 Based on the geometry of the skin sheet 9, it is stretched and loaded through the jaws 7 of the stretching machine. The process involves pre-stretching the skin sheet blank, then bending the skin sheet 9 using the working surface of the multi-point stretching die 10, and then stretching it again. During the forming process, the stress in all cross-sections of the skin sheet 9 continuously increases, and the forming is completed without unloading.

[0047] Step 4: Upper pressure beam 1 descends: Upper pressure beam 1 is connected to hydraulic cylinder 2, and hydraulic cylinder 2 is connected to hydraulic cylinder seat 3. Hydraulic cylinder seat 3 has a drive device that can move along the X-axis of guide rail 4. Upper pressure beam 1 moves along the X-axis to above the skin part processing area via hydraulic cylinder seat 3 with drive device. Under the action of hydraulic cylinder 2, upper pressure beam 1 moves downward along the Z-axis and cooperates with the action of robotic arm 5 to move electromagnetic coil 6 mounted on robotic arm 5 to the local feature to be formed area of ​​skin sheet 9.

[0048] Step 5: Local Electromagnetic Forming of Electromagnetic Coil 6: When the electromagnetic coil 6 moves to the local feature to be formed area of ​​the skin sheet 9, a pulsed current is passed through it to drive the electromagnetic coil 6 to generate a strong magnetic field. This induces eddy currents in the skin sheet 9 and forms a Lorentz force, driving the local feature at the skin sheet 9 as shown in the image. Figure 5 As shown, the material undergoes high-speed plastic deformation at localized features. Electromagnetic pulse forming (EMF) offers advantages such as non-contact forming, cleanliness, and high efficiency. Furthermore, the electromagnetic force can be applied in a repulsive or attractive manner through timing control, and can be flexibly adjusted in time and space. A schematic diagram of the locally formed part is shown below. Figure 5 .

[0049] Example 1

[0050] The skin sheet 9 to be formed is made of 2B06 aluminum alloy, with dimensions of 750mm × 125mm × 1mm (length × width × thickness). Additionally, the elastic pad 8 is made of black rubber, with dimensions of 560mm × 280mm × 10mm (length × width × thickness), a Poisson's ratio of 0.49, and an elastic modulus of 8MPa. The electromagnetic coil 6 is mounted on the robotic arm 5 on the upper pressure beam 1 and can move along the length of the skin sheet 9. The discharge voltage is 7000V. The discharge energy (E) of the EMF device is related to the discharge voltage (U) and capacitance (C). U = 7kV, C = 640μF, therefore E = 15.68kJ. The local features of the part are well formed, and the dimensional accuracy meets the requirements.

[0051] It should be noted that, for those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention, and no reference numerals in the claims should be construed as limiting the scope of the claims.

[0052] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. An electromagnetic pulse forming device for local features of a skin part, characterized in that: The system includes an upper pressure beam, a robotic arm, an electromagnetic coil, and a multi-point forming mold. The multi-point forming mold is mounted on a fixed base plate. Both ends of the skin sheet are clamped and pulled by the jaws of a forming machine and then pressed tightly against the top surface of the multi-point forming mold. The shape of the top surface of the multi-point forming mold is adjustable. One end of the robotic arm is fixed to the upper pressure beam, and the other end of the robotic arm is equipped with the electromagnetic coil. The electromagnetic coil is used for electromagnetic forming of the skin sheet. The position of the upper pressure beam is adjustable.

2. The electromagnetic pulse forming device for local features of skin parts according to claim 1, characterized in that: The multi-point forming die is composed of multiple regularly arranged basic bodies distributed in a matrix, and the shape of the multi-point forming die is adjusted by a computer control system.

3. The electromagnetic pulse forming device for local features of skin parts according to claim 2, characterized in that: The basic body includes multiple basic body punches. Each basic body punch includes a punch body, a ball head, and a hydraulic cylinder adjusting rod. The hydraulic cylinder adjusting rod is mounted on the fixed base plate. The top telescopic end of the hydraulic cylinder adjusting rod is sequentially connected to the ball head and the punch body. The skin sheet is tightly attached to the punch body.

4. The electromagnetic pulse forming apparatus for local features of skin parts according to claim 3, characterized in that: The computer control system controls the hydraulic cylinder adjusting rod to adjust the height of each of the basic punches according to the basic punch height data calculated by the software, so as to construct the multi-point drawing die of the required shape. The software is installed in the computer control system.

5. The electromagnetic pulse forming apparatus for local features of skin parts according to claim 1, characterized in that: The skin panel is placed on the multi-point stretching mold, and an elastic pad is placed between the skin panel and the multi-point stretching mold.

6. The electromagnetic pulse forming apparatus for local features of skin parts according to claim 1, characterized in that: Guide rails are provided on both sides of the fixed base plate, and the upper pressure beam can move along the guide rails to the upper part of the processing area of ​​the skin sheet material under the drive of the driving device.

7. The electromagnetic pulse forming apparatus for local features of skin parts according to claim 6, characterized in that: The upper pressure beam is connected to the hydraulic cylinder, the hydraulic cylinder is connected to the hydraulic cylinder seat, and the hydraulic cylinder seat is equipped with a driving device. The driving device is used to drive the hydraulic cylinder seat to move along the direction of the guide rail so that the upper pressure beam moves above the processing area of ​​the skin sheet.

8. The electromagnetic pulse forming apparatus for local features of skin parts according to claim 1, characterized in that: The electromagnetic coil is connected to the pulse current system.

9. The electromagnetic pulse forming apparatus for local features of skin parts according to claim 1, characterized in that: The number of robotic arms is greater than or equal to two, and each robotic arm is equipped with an electromagnetic coil at its bottom end. The electromagnetic coil at the bottom end of each robotic arm is used to perform local feature shaping on different positions of the skin sheet.

10. A method for forming local features of a skin part using electromagnetic pulse forming, applied to the electromagnetic pulse forming apparatus for forming local features of a skin part according to any one of claims 1-9, characterized in that, Includes the following steps: Step 1: Multi-point forming die adjustment: The computer control system adjusts the height of each basic punch according to the basic punch height data calculated by the software to construct the multi-point forming die of the required shape. Step 2, fixing the skin panel: Place the skin panel on the adjusted multi-point stretching mold, and place an elastic pad between the skin panel and the multi-point stretching mold. The jaws of the stretching machine clamp the skin panel and stretch it according to the adjusted multi-point stretching mold, so that the skin panel is tightly attached to the multi-point stretching mold. Step 3, Skin sheet stretching and forming: According to the geometry of the skin part, the skin sheet is stretched and loaded through the jaws of the stretching machine, then bent using the working surface of the multi-point stretching die, and then stretched again; Step 4, Upper pressure beam descends: Driven by the hydraulic cylinder seat with the drive device, the upper pressure beam moves along the guide rail to above the processing area of ​​the skin sheet. The upper pressure beam moves downward under the action of the hydraulic cylinder and cooperates with the action of the robotic arm to move the electromagnetic coil installed on the robotic arm to the local feature to be formed area of ​​the skin sheet. Step 5, Local Electromagnetic Forming with Electromagnetic Coil: When the electromagnetic coil moves to the local feature area to be formed of the skin part, a pulse current is passed through to drive the electromagnetic coil to generate a strong magnetic field, inducing eddy currents in the skin sheet and forming Lorentz force, driving the material at the local feature of the skin sheet to achieve high-speed plastic deformation.

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