Cutting through electromagnetic forming

Established cutting technologies generally require cutting gaps in the range of 0.5% (in fine blanking) to 10% of the thickness of the material to be cut. Especially when processing ultra-thin sheets or foils, the manufacture and assembly of tools with highly precise cutting gaps pose a significant challenge. This challenge can be completely circumvented by applying cutting through electromagnetic forming. The reason is that this is not a shear cutting process, as the material is not divided by two cutting edges moving past each other. Instead, the workpiece, subjected to electromagnetic forces, is formed around a cutting edge until it fractures in a controlled manner. Depending on the arrangement of the inductor (which generates the electromagnetic forces), the workpiece, and the single cutting edge required for the process, the technology can be used for punching holes or for trimming. Regardless of the process variants, there is no cutting gap in electromagnetic forming, and the requirements for the accuracy of the inductor's relative position to the cutting edge are very low, regardless of the thickness of the material to be cut. Unlike the shear stresses and deformations in shear cutting, cutting through EMF is characterized by bending stresses and deformations, similar to the fracture separation known from connecting rod manufacturing. However, the application spectrum is more focused on thin sheets or even foils made of aluminum or non-ferrous metals. In addition to the simple tool design, a significant reduction in the adhesion and burring frequently occurring in shear cutting of these materials is advantageous. Very thin foils can potentially even be cut in stacks without loss of quality to increase process productivity.

Due to the different cutting characteristics, the cut edges produced by EMF cutting also differ from those produced by shear cutting. Notably, the absence of burrs allows for safe handling of the cut parts without further finishing. In EMF cutting of thin sheets, this is accompanied by a significant draw-in on the side of the component facing the inductor, which transitions directly into the fracture surface.