Study of bifurcations produced by non-contact magnetic cutting in aluminum plate

Non-contact magnetic cutting (NCMC) is a process by which repetitively applied pulsed magnetic fields are used to extend and direct very fine cuts in metals. A companion paper, presented at this conference, explains the technique in more detail. Under the right conditions, the NCMC process can produce fine, precise cuts, but different conditions produce bifurcations in the cuts, which are not desirable. This paper examines a series of experiments and finite element simulations to determine the conditions that produce bifurcations when using the NCMC process to cut aluminum plate. We discuss the relative importance of two systematic factors and one random factor leading to the formation or suppression of bifurcations. The Lorentz force acts in the direction of the cut and tends to suppress the formation of bifurcations, whereas the principal stress are directed at 45 degrees to the cut and favor the formation of bifurcations. The shape in which molten aluminum resolidifies between pulses is a random factor that can lead to the formation of bifurcations.