Sheet metal forming by stamping and deep drawing is widely used in automotive, aerospace, and appliance manufacturing industries. In the vehicle industry, there is a constantly increasing need for reduction of structural weight in order to increase fuel efficiency. This is being accomplished by the use of materials such as high strength steel, and aluminum and magnesium alloys, which have a high strength to weight ratio [1]. However, these materials also tend to have lower formability. Impulse based processes, such as electrohydraulic [2] and electromagnetic [3] forming have been demonstrated to stretch many materials beyond their conventional forming limits. However, such increase in formability is not ubiquitous and one cannot rely on increased formability alone to form parts using a single step impulse based process. Another way is to control the strain distri- bution in the stamped part. Ideally, nowhere in the part should be excessive compressive strains causing wrinkling or excessive tensile strains that can cause tearing. Techniques like active draw bead control [4], active blank holder force control [5], lubrication [6] and blank optimization are used to control metal flow and distribute strains more uniformly in a stamped part. Here, a different approach, electromagnetically assisted sheet metal forming (EMAS), has been discussed.

Before delving into the process idea of EMAS, it is useful to describe electromagnetic forming (EMF), which is a well known process [7]. During EMF, the forming forces are generated from magnetic repulsion between a stationary primary coil and the workpiece. A high voltage discharge from a capacitor bank causes the flow of a transient current

through the primary coil which is placed proximally to the workpiece. The induced eddy currents in the workpiece are directionally opposite to the one in the primary coil. There- fore, a repulsive Lorentz force is created between the two current carrying conductors. By changing the initial charging voltage, the driving magnetic pressure pressure, which is typically a few hundred megapascals and lasts over a time period around 10 µs, can be controlled [8]. In EMAS, EMF augments a conventional stamping process This process was initially conceived and developed by Daehn and co-workers [9].