Abstract: A process is provided for controlling a friction stir welding process using one of two methods where standard depth/force control is inadequate. Both methods use sensors that are combined and compared to generate forge force, cross-seam force, and traverse forces. Cross-seam force is force perpendicular to the direction of travel and traverse force is aligned with the direction of travel. Forge force is the force applied in the depth direction. The first method uses only cross-seam force and the second method uses cross-seam force combined with traverse force as an input into a control loop that sets the tool depth command. The first method also uses spindle power to control the speed of the spindle. Both methods use forge force only as a safety limit. The control loop maintains forge depth better than forge force, temperature, or spindle power.

Abstract: An apparatus and method for a continuous supply of feedstock for a friction stir additive manufacturing method has a rod supply system that transports feedstock segments to a shuttle. The rod supply system has actuators that are coupled to allow movement of the delivery point of the feedstock. The shuttle indexes the feedstock to be on axis with the spindle and rotates it to match the speed and orientation of the spindle before it makes contact with other feedstock currently being deposited. An upper thrust mechanism moves the feedstock from the shuttle to a one-way collet and applies deposition pressure through the collet while the collet raises. Once raised, the collet then applies deposition pressure to the feedstock and the upper thrust mechanism retracts so the shuttle can index again and present additional feedstock. The process can repeat to continuously supply feedstock until the workpiece is complete.