Robots can be used to manipulate the rotating friction stir welding tool in three dimensions, leading to a machine that can weld in three dimensions. The robotic drive system that manipulates the welding head needs to be sufficiently robust to react the welding force being applied to the friction stir welding tool.
The need to react the downforce means that complex tooling is required for complicated 3-D joints. The advent of new tool designs, which have a low downforce requirement, would make the prospects of using robots much more attractive, as this will reduce the complexity of the support tooling, and the robustness of the robot.
For further information see Joining Technologies.