Electromagnetic incremental forming (EMIF): A novel aluminum alloy sheet and tube forming technology

Large parts cannot be shaped by conventional electromagnetic forming method due to the limitation of the strength of working coil and the capacity of capacitor bank. In this paper, based on the principle of single point incremental forming, a new method named electromagnetic incremental forming (EMIF) has been proposed. The method makes use of a small coil and small discharge energy to cause workpiece local deformation in a high speed. Finally, all local deformations accumulate into large parts. For the electromagnetic incremental sheet forming, the effect factors of processing parameters namely discharge voltage, vent hole, discharging times in a fixed position and the number of discharge region, on final sheet shape are investigated by using AA3003 aluminum alloy parts. In addition, two different simulation strategies are proposed to predict electromagnetic incremental sheet and tube forming process. For method 1: the technology like “birth-death element” is used to indirectly describe the movement of the coil and the morphing technology is used to make the air change with the workpiece deformation. For method 2: the coil can directly move to a special position and the remesh technology is used to consider the effect of the workpiece deformation and the movement of coil on magnetic analysis. It is found that method 1 cannot be used for electromagnetic incremental sheet forming process if overlap region exists in two adjacent discharge regions. However, method 1 can successfully predict electromagnetic incremental tube forming. And method 2 can be used for electromagnetic incremental sheet or tube forming. Both of the experimental and simulation results demonstrate that this new technology is feasible to produce large part.