Custom Low-Cost Force Measurement Methods In Friction Stir Welding

Abstract

Friction Stir Welding (FSW) is a solid-state joining technique that is rapidly expanding to a wide range of industries. In this thesis, custom low-cost force measurement methods developed specifically for use with FSW are presented. Force data can provide insight into weld quality, resulting mechanical properties, and even tool wear. Implementation of force control increases the applicability of FSW, and some research suggests that weld characteristics can be manipulated using force control.

A method of measuring axial force is presented that exploits the in-process deflection of a robotic link for measurement purposes. Additionally, a custom low-cost force transducer designed specifically to withstand the thermal and mechanical loads of FSW and capable of measuring all forces of interest in FSW is developed, with a focus on torque measurement implementation as the first stage of development. The process for designing and implementing these two systems is outlined in great detail from concept to completion. The cost for each system is also analyzed and is shown to be lower than any commercially available load cell that could be utilized in FSW.