Influence of punch velocity during high-speed blanking of 22MnB5 steel with electromagnetic drive

High blanking velocities offer many production advantages in terms of cutting edge quality and energy efficiency. Currently, hydraulic drives are used to accelerate the blanking punch in high-speed blanking (HSB) processes. This results in punch velocities in the range of 3 to 10 m/s. The main objective of the study is to extend the process limits in terms of punch velocity and to analyze the corresponding influence on the blanking zone properties. The approach is to evaluate an alternative drive concept, using electromagnetic (EM) forces, to accelerate the punch. The experimental setup consisting of an EM drive and a blanking tool was designed, implemented and used for an experimental parameter study. The resulting blanked surfaces of 22MnB5 steel were characterized by metallographic investigations focusing on adiabatic shear band (ASB) formation. The research methodology includes detailed numerical simulations of the blanking process using LS-DYNA, coupled with an experimental study to determine the shearing mechanisms for a maximum ASB distribution over the cut surface of the blanked parts. The results show the high potential of EM HSB to produce parts with a 100% ASB distribution in the cutting surface and thus further functional surfaces with unique properties.