Abstract: An ultrasonic welding apparatus joins metal pieces, such as wires, which are placed in a weldment zone where the metal pieces are subjected to pressure through a compressive height anvil and an adjustable width anvil, and intimate contact is made with a sonotrode of an ultrasonic stack. A first electric motor actuates movement of the height anvil to develop a compressive force for ultrasonic welding of the metal pieces. A second electric motor can position the width anvil before and during welding. A sensor, such as a load cell, measures the compressive force developed. The sensor directly can measure the load on the height anvil independent of the ultrasonic stack. A software algorithm can compensate for deflection of the load cell sensor and lost motion in the first electric motor actuating movement.

Abstract: An ultrasonic welding apparatus joins metal pieces, such as wires, which are placed in a weldment zone where the metal pieces are subjected to pressure through a compressive height anvil and an adjustable width anvil, and intimate contact is made with a sonotrode of an ultrasonic stack. A first electric motor actuates movement of the height anvil to develop a compressive force for ultrasonic welding of the metal pieces. A second electric motor can position the width anvil before and during welding. A sensor, such as a load cell, measures the compressive force developed. The sensor directly can measure the load on the height anvil independent of the ultrasonic stack. A software algorithm can compensate for deflection of the load cell sensor and lost motion in the first electric motor actuating movement.