Abstract: A device to determine a state of an ultrasound welding process, which can be carried out using an ultrasound tool, includes a sensor element and an evaluation unit. The sensor element is configured to detect an electrical control signal from an ultrasound tool. The evaluation unit is configured to determine a signal property of the control signal and to determine the status of the ultrasound welding process based on a reference signal profile and on the determined signal property. An assembly with an ultrasound welding system and a method are also included.

Abstract: The present invention relates to a method for determining at least one physical characteristic value of an electromechanical oscillatory system, which comprises a piezoelectric element and at least one additional element coupled, with respect to oscillation, to the piezoelectric element, the piezoelectric element having an electrode and a counter electrode.

Abstract: The present invention concerns an ultrasonic vibration unit having a converter (1) for converting an electric ac voltage into a mechanical ultrasonic vibration and a sonotrode which is vibrationally coupled to the converter (1), wherein the sonotrode and the converter (1) are matched to each other in such a way that the ultrasonic vibration unit can vibrate with a natural frequency f, in which a standing longitudinal wave having at least one vibration node and at least two vibration antinodes is formed within the ultrasonic vibration unit.

Abstract: A device to determine a state of an ultrasound welding process, which can be carried out using an ultrasound tool, includes a sensor element and an evaluation unit. The sensor element is configured to detect an electrical control signal from an ultrasound tool. The evaluation unit is configured to determine a signal property of the control signal and to determine the status of the ultrasound welding process based on a reference signal profile and on the determined signal property. An assembly with an ultrasound welding system and a method are also included.

Abstract: The present invention concerns an ultrasonic vibration device having a sonotrode and a converter, wherein the converter has a piezoelectric actuator for converting an electrical alternating voltage into a mechanical vibration, wherein there is provided a first piezoelectric sensor element which outputs a first measurement signal which varies in dependence on the vibration amplitude of the mechanical vibration. To provide an ultrasonic vibration device which allows measurement of at least one intensive state variable like for example the temperature or the ageing state of the piezoelectric actuator it is proposed according to the invention that there is provided a second piezoelectric sensor element which outputs a second measurement signal which varies in dependence on the vibration amplitude of the mechanical vibration, wherein the second piezoelectric sensor element differs in a physical property from the first piezoelectric sensor element.

Abstract: The present invention concerns an ultrasonic vibration unit having a converter (1) for converting an electric ac voltage into a mechanical ultrasonic vibration and a sonotrode which is vibrationally coupled to the converter (1), wherein the sonotrode and the converter (1) are matched to each other in such a way that the ultrasonic vibration unit can vibrate with a natural frequency f, in which a standing longitudinal wave having at least one vibration node and at least two vibration antinodes is formed within the ultrasonic vibration unit.