Authors:	M. Gutensohn, G. Wagner, D. Eifler. R. Sust, D. Stroh
Title:	Reduction of Adherence of Aluminium on Ultrasonic Welding Tools
Abstract:	The ultrasonic metal welding process is well established in the automotive industry to join copper wires in wiring harness. The welding method is also very well suited to weld aluminium components with a high reproducible strength. But the extremely good ultrasonic weldability of aluminium often leads to an adherence on the sonotrode coupling face. In systematic investigations at the Institute of Materials Science and Engineering at the University of Kaiserslautern the reasons for the adherence were investigated and methods to reduce this effect were identified for the first time. Preliminary tests were carried out with sheet metal samples to understand basically the reasons for the adherence effect. By systematic variation of the ultrasonic welding parameters and the tool coatings it was possible to join aluminium wires with large cross sectional areas of up to 25 mm2 with a strength of about 700 N nearly without adherence of aluminium on the welding tool.