Production and use of adaptive pulsed Lorentz force for multi-step electromagnetic sheet metal forming: method, experimental validation, and application

This paper proposed a novel electromagnetic actuator to produce an adaptive pulsed Lorentz force and use it to shape sheet metal workpieces. Such an adaptive pulsed Lorentz force can adapt its spatial distribution with respect to the sheet profile, which may stimulate a wide group of process variant. Herein, we shall introduce this adaptive pulsed Lorentz force to realize an energy-efficient and flexible multi-step electromagnetic forming process. And we shall validate the feasibility and advantages of the proposal by a combination of simulation and experimentation. Our simulation and experimental results suggested that the proposed multi-step process may resolve two critical issues (that is, the limited forming capability and the limited deformation control) for electromagnetic forming process. For the forming capability issue, our proposed process can successfully realize a forming mission which cannot be realized by conventional electromagnetic forming process for the relatively high mechanical strength of the workpiece; in addition, the proposed process has been successfully applied for shaping a sheet metal with 1000 mm length-scale, and compared with a previous work on a similar manufacturing case, the energy capacity required for the proposed process is only 25% of that for the former. For the deformation control issues, the proposed process can substantially reduce or even eliminate the forming defects of the wrinkling and rebounding by using a multi-step calibration process, thus substantially improving the forming quality. In summary, the proposed electromagnetic actuator and process are expected to break through several existing technical bottlenecks, and thus facilitate the advances for electromagnetic forming.