Applying torque based control to Friction Stir Extrusion

Abstract

A series of Friction Stir Extrusion welds with varying groove geometries were performed to determine the effect on processing forces. A clear correlation with groove geometry was observed for z-force, torque, and y-force. The data was used to design a torque-based plunge depth controller. All the welds from the prior series of welds were repeated with the controller applied. When comparing the controlled welds to the uncontrolled welds, the use of the controller eliminated surface defects at larger groove cross-sectional areas, and the controlled welds maintained 10 % of the reference torque. The controller demonstrated good transient performance for both a step and continuous linear increasing groove widths.