Patent ID: 8261959

Claim:
A friction stirred welding system of the type including a backing, said system comprising: a spindle; a rotating tool adapted to be accepted by the spindle, said spindle in use rotating the tool in contact with a workpiece to heat and weld the workpiece in solid state without causing the workpiece to melt; an electrically controlled actuator structured to determine the axial position of said tool in six degrees of freedom; a sensor that measures the downforce the rotating tool applies to said workpiece; a control system coupled to said sensor, said control system being structured to control said electrically controlled actuator to correct axial tool position at least in part in response to said measured downforce to thereby maintain the load between tolerance limits, said control system being further structured to avoid oscillations of the load applied to the workpiece by applying proportional integral derivative control to maintain the load constant or substantially constant during welding, said control system including a closed-loop control arrangement that controls rate of rotation of the tool; a laser sensor that is adapted to be accepted by the spindle and interchangeable with said rotating tool, said laser sensor in use mapping the axial distance between the spindle and the backing; an alarm coupled to the laser sensor, said alarm indicating if the axial distance between the tool and the backing is less than a predetermined threshold distance determined based at least in part on measured variations; and a data logger that logs welding parameters during welding.