Patent ID: 8393520

Claim:
An ultrasonic stir welding system, comprising: a stationary base; a welding head assembly to include a plate spaced apart from said base and a rod with an end of said rod spaced apart from said base, said rod passing through said plate wherein said rod is rotatable about a longitudinal axis thereof; a rotational drive source coupled to said rod for rotating said rod about said longitudinal axis thereof during a welding operation; an ultrasonic energy source coupled to said rod; a controller coupled to said source for controlling said source such that a series of on-off ultrasonic pulses is generated and applied to said rod during said welding operation and such that said on-off ultrasonic pulses propagate parallel to said longitudinal axis of said rod, said controller controlling at least a pulse rate associated with said on-off ultrasonic pulses; and at least one additional ultrasonic energy source coupled to at least one of said base and said plate, said at least one additional ultrasonic energy source generating additional on-off ultrasonic pulses for application to at least one of said base and said plate wherein said additional on-off ultrasonic pulses propagate perpendicular to said longitudinal axis of said rod.