Electrohydraulic incremental bulk metal forming

Abstract

Electrohydraulic forming is a working media based high speed technique that is usually applied for sheet metal processing. In this process a shock wave acts as a flexible punch that transmits the punching force in a very short period of time. This force is usually used to accelerate the workpiece towards the passive tool. In Contrast to sheet forming, the electrohydraulic method is still not adapted to bulk forming. Although, the exchange of a mechanical rigid punch by a shockwave with a flexible shape enables special advantages especially if parts with millimeter dimensions or smaller are to be processed. But in case of deep and small cavities with a high aspect ratio are to be filled, the forming energy is not transferable within one shock wave. To overcome these obstacles the incremental electrohydraulic forming is introduced. As an example, the electrohydraulic extrusion of cylindrical samples (aluminum Al99.5) with an initial diameter of 1.5 mm was performed with a series of consecutive shock waves.

Keywords

• Micro forming
• Extrusion
• Aluminium