Herrmann Ultraschalltechnik has introduced a piezo-electric cutting unit. A gap sensor continuously measures the gap size between weld horn and cutting edge and a high-resolution piezo-electric actuator corrects the target value deviations. This way, the gap size remains reliably constant. In addition, the entire acoustic stack is supported in a flexure free from clearance. Extremely precise adjustments can be achieved. A manual adjusting range of +/- 1.0 mm is possible. The control time is below one millisecond. To perform individual steps, the control of the new piezo-electric cutting unit is integrated into the generator. If several cutting units are to be operated simultaneously, this is possible with a higher controller. Telephone: 49-7248-79-0; Fax: 49-7248-7939.