Abstract: The invention relates to a method for adjusting the operating frequency of a vibratory welding system producing orbital motion comprising a workpiece socket head which is mounted to resilient means. The head is driven by electromagnetic means to produce orbital vibrations to be constricted to a vibratory plane for welding workpieces, in particular made of plastic material, wherein the frequency is varied within a predetermined range of frequencies to detect the geometrical configuration of the vibration, followed by selecting the frequency exhibiting the best possible vibratory configuration and defining the operating frequency to which the system will be adjusted.

Abstract: The invention relates to a method for a unique control of the frequency and utput power of a digital generator, in particular for an ultrasonic welding process. Based on a digital processing, the method according to the present invention compensates not only for variations of the resonant frequency in a broad range, but further provides to control a shifting of the resonant point during the welding process in response to temperature or pressure variations. Power variations caused by variations of the line supply voltage or by the pressure are detected and levelled out by the software. The software monitors the overall operation of in-line machinery, matches its parameters and monitors the complete cycle. The software further ensures an optimum efficiency and effectively protects the end stage against stress caused by high-reactive currents.