Electrohydraulic full-forward extrusion of small parts through high aspect ratio forming channels

Abstract

Electrohydraulic incremental bulk forming was introduced as a novel micro part forming technology. Forming of parts from different materials and different initial diameter values was investigated in single-stage full-forward extrusion in recent work. In this paper, multi-stage extrusion in high aspect ratio forming channels is presented. Thereby, the aspect ratio of forming channel is high, when the channel length is much higher than the channel diameter and formed part length. Analytical and experimental investigations are carried out to correlate the supplied and required energy for extrusion. Experiments were made using an optical access made of sapphire as part of the extrusion channel to measure the position during forming increments. The influence of channel depth and curvature as well as of fluctuations in the transmitting media on the energy transmission to the formed EN AW-6061 aluminum alloy parts were found to be low.