TWI

A methodology to facilitate cost-effective friction stir welding (FSW) of large and complex 3D structures is presented based on a parallel kinematic machine concept called Pentapod, and welding trial results for spherical structures and dissimilar material joints are reported. The capabilities of various parallel kinematic machines are summarised and the design of the 5-axis Pentapod PG2000 system is described. Process control methods with respect to force, torque and position control are outlined. Trials were undertaken using standard FSW tools with a concave shoulder and a cone shaped pin with scroll, and results were obtained for a cylindrical test sample, a convex and concave curved test sample with a closed radial butt joint, large thin-walled structures with flat or curved form, and dissimilar butt or overlap joints between relevant copper alloys and AW 1050A aluminium.

9th International Symposium, 15-17 May 2012, Session 9A: Process II, Paper 04