FSW Process Enhancements

This presentation will describe ongoing development work at TWI focusing on the enhancement of the FSW process to improve joint performance, increase process flexibility and assure weld quality.

Recent work in three main areas will be highlighted:

1. Low Heat Input FSW

The development of Stationary Shoulder Friction Stir Welding (SSFSW) for a range of applications will be discussed. SSFSW results in a significant reduction in the extent and severity of the thermal profile experienced by the top surface of the weld, which is often a key area with respect to joint performance. SSFSW can be used to enhance surface quality/performance, ensure weld stability, improve tool lifetimes/economics, and allow greater process flexibility.

2. Low Force FSW

The novel technique of Floating Bobbin Tool FSW will be presented, and its benefits and applications will be discussed. Floating Bobbin Tool FSW produces high quality joints with a uniform thermal profile, and guaranteed full penetration. The process develops significantly reduced forces compared to conventional FSW, allowing flexible application on relatively simple low-cost machine tools.

3. On Line Quality Assurance for FSW

The development of TWI’s new ARTEMIS unit will be presented. This system is essentially a heavily instrumented tool spindle attachment, which can be fitted onto any standard FSW machine. The unit has been developed to allow in-process observation of FSW mechanisms and tool behaviour, and provides a new level of process information at the point of the tool. The ARTEMIS unit can be used for FSW procedure development and tool optimisation work, as well as for on-line detection of flaws and process events.

In summary this presentation will provide an overview of recent development work at TWI, focusing on the enhancement of the FSW process. Selected examples will be shown throughout to highlight the benefits of these novel technologies/approaches.