Electromagnetic attractive forming of aluminum alloy sheets utilizing a low-frequency half-wave current

Abstract

ABSTRACT The generation and optimization of attractive force between the coil and the workpiece is of significance for expanding the application of electromagnetic forming. In this work, a method using a low-frequency half-wave current is proposed to improve the attractive force, and to achieve a high-performance attractive forming. To verify the effectiveness of this method, an RLC circuit with a thyristor switch is introduced to generate the half-wave current, and the deformation behavior of an AA1060-H24 sheet is analyzed. According to both numerical and experimental investigations, it is demonstrated that the aluminum alloy sheet can be efficiently attracted toward the coil surface with a maximum deformation of more than 6 mm after a single discharge. On this basis, a series of simulations and experiments are carried out to clarify the effects of the discharge energy and current frequency on the attractive forming process. It is found that under the same forming depth, the required discharge energy and coil temperature rise for a smaller capacitance (1280 μF) can be decreased by almost 35% and 50%, respectively, compared to that for a larger capacitance (2880 μF). The obtained results are of certain value to promote the development of electromagnetic attractive forming.