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.

Negative magnetophoresis-based magnetic levitation (MagLev) is a label-free and simple method to levitate and manipulate nonmagnetic materials, which is a recent research topic of interest in density-based analysis. However, the existing MagLev mainly uses two permanent magnets with a longitudinal symmetry structure, facing difficulties in achieving both a large measurement range and high measurement sensitivity simultaneously. To solve this, a novel asymmetrical cylindrical MagLev configuration is proposed involving two cylindrical magnets with different thicknesses. On this basis, the characteristics of magnetic force at different magnet spacings are investigated, and the levitation behavior of the samples with different densities is explored. According to the numerical and experimental results, it is interestingly found that two different continuous functional regions with inward radial magnetic forces can be formed for density measurement by adjusting the magnet spacing. The functional measurement regions at small magnet spacing and large magnet spacing serve a large measurement range and a high measurement sensitivity, respectively. Importantly, the measurement range and sensitivity in the new MagLev are both better than conventional MagLev. These findings are of significance to understanding the MagLev process and to promote its practicality.