1、 General introduction of electromagnetic assisted forming system Electromagnetic forming belongs to high-energy (high-speed) forming technology. Firstly, the electric energy should be stored in the high-voltage capacitor. When the high-voltage switch is closed, the capacitor can discharge the coil quickly (US level) and generate a changing pulse magnetic field around it. When the pulse magnetic field passes through the workpiece, the induced current (eddy current) will be generated in the metal workpiece, and the charged metal workpiece will be in a rapidly changing magnetic field When the magnetic pressure reaches the yield strength of the material, the metal workpiece will have plastic deformation to achieve the purpose of forming metal parts. Electromagnetic forming technology has the characteristics of easy and accurate control of processing energy, fast forming speed, high precision of forming workpiece, small elasticity of parts after forming, improvement of plastic deformation ability of materials, simple mold and strong universality of equipment, easy to adopt composite process and realize automatic production, green and environmental protection in the whole forming process, which has been widely used in aviation, aerospace, weapon industry Automobile manufacturing, light chemical industry, instruments and electronics and many other fields. Electromagnetic forming can be widely used in plate forming, sheet punching, punching, electromagnetic bulging and reducing of pipe, flanging and connection, stamping and forming, multi process composite forming, assembly of assembly parts, powder compaction, electromagnetic riveting, electromagnetic welding and storage of radioactive materials, etc. it is the preferred forming method for some special parts. For example, precision sizing of large components, burr free punching of diaphragm, processing of complex shape pipe fittings, forming of missile clamp, sizing of instrument cabin, forming of aircraft turbine engine room, assembling of torque shaft and connecting rod; connection of automobile air-conditioning reservoir, heat exchanger, universal joint frame, cam, gear, etc. with drive shaft or universal shaft pipe; assembly of electronic components such as fuse, insulator, etc In the nuclear industry, fuel rod forming, nuclear waste container sealing, electromagnetic riveting have been widely used in Boeing 737, 747, 767, and electromagnetic powder pressing has opened up a broad application prospect for electromagnetic forming technology in the functional ceramics industry, sensitive components and sensors industry. 1.1 electromagnetic forming principle The important characteristic of electromagnetic forming is that the energy release time is short, which is only microseconds, while the deformation time is very short for millisecond electromagnetic pulse load, while the deformation of sheet metal in this period of time is not large, but under the action of magnetic field force, the metal obtains a great acceleration and a great kinetic energy, and after the load disappears, the absorbed kinetic energy is converted into plastic deformation energy, and the inertial force is In the forming process, the movement speed of the workpiece during deformation can reach hundreds of meters per second, forming from the conical part with high deformation; the die forming is commonly used for stamping, local rib pressing, concave pressing and curved part forming, etc. the flat plate blanking can be realized by using flat coil and indirect processing, and the burr free blanking can be realized when the process parameters are reasonable. 1.2 characteristics of electromagnetic forming technology (1) Electromagnetic forming has no mechanical contact. It uses magnetic field as the medium and does not need the surface contact of workpiece and tool. Therefore, there is no mechanical scratch on the surface of workpiece and the surface quality of workpiece is good. (2) The workpiece has uniform deformation and stress, small residual stress, high fatigue strength and long service life. After processing, it does not affect the mechanical, physical and chemical properties of the parts, nor does it need heat treatment. (3) High forming accuracy. The electric energy of electromagnetic forming can be precisely controlled, the energy produced by the working coil and the change of the force exerted on the workpiece can be controlled within 0.5% of the total amount, and the machining repeatability is also high. (4) It is very convenient to achieve high-speed forming, which can work hundreds of times per minute, and has similar production efficiency with ordinary stamping. (5) Electromagnetic forming (EMF) is a green processing method, which will not produce waste residue, waste liquid and other pollutants in the process of EMF, which is conducive to environmental protection. (6) Materials with poor conductivity are difficult to process. Good electrical conductivity is a necessary condition for electromagnetic forming materials, which is also one of the main factors limiting the application of electromagnetic forming.