Piezo driven prestressing of die-system for microforming of metal components

In micro forming, the increased surface to volume ratio makes ejection of an extruded component to an often complicated process. The aim of this work has been to demonstrate the possibility to reduce the force required to eject the component, by controlled pre-stressing of the die, before, during and after the forming process. The level of required prestress has been evaluated by FE analysis of the interaction between the forming process and the elastic deflection of the tool-system. A test rig has been designed containing four piezo actuators mounted symmetrically around the circumference of the die cavity. Mechanical amplification has been used to increase the pressure created by the piezo actuator to reach the level required for prestressing of a bulk forming tool.