Bonding - More than materials | Herrmann Ultraschall

Visual representation of the frequency range with voltage curves. ULRICH VOGLER STUDIED MECHANICAL ENGINEERING IN KARLSRUHE – LIKE THOMAS HERRMANN. HE BEGAN HIS JOUR- NEY AT HERRMANN ULTRASCHALL IN 1991. THE HEAD DEVELOPER SIMPLY LOVES LAKE CONSTANCE, HAVING RELOCATED THERE, AND IS AN ENTHU- SIASTIC MARATHON RUNNER. THREE MILESTONES AND IRREPLACEABLE HELPERS IN SONOTRODE DEVELOPMENT: 1. The determination of the optimal sonotrode geometry using special calculation systems and the finite element method (FEM). The result is graphical displays of the frequency range, the amplitude values, and the voltage curves. 2. The visualization of the actual amplitudes (sonotrode travel) using a laser Doppler vibrometer (LDV). This enables adjustment of the tool simulation to reflect the reality. 3. A deeper understanding of the ma- terial properties of special titanium, aluminum, and steel alloys from which sonotrodes are manufac- tured. Here, too, the special laser technology was helpful and it was possible to recognize material pa- rameters better and to theoretically calculate the vibrating behavior even more accurately and to implement it better in practice. The geometry of the components to be welded can also bring ultrasonic welding to the limits of what is feasible. “If a component has many height dif- ferences and shapes, this also brings us to the limit. But we don’t let a little thing like that stop us; we try to make it possible,” says Ulrich Vogler. The supreme discipline: complex, multipart sonotrodes consisting of a composite sonotrode and screw-in pin sonotrode. In order to bypass the limitation posed by the size of the applications or the width of the weld joints up to a certain level, Herrmann uses the specially de- veloped, robust dual and triple systems. In the dual system, two stacks lie closely beside each other, while in the triple system three do. “That is the future,” emphasizes head developer Vogler. If the weld joint is too wide to be welded with a single sonotrode, this is where the system perfected by Herrmann comes in. “COMPLEX, MULTIPART SONOTRODES MAKE THE IMPOSSIBLE POSSIBLE.” 46