| 摘要 |
The invention relates to a method for sealing, connecting, separating, perforating, and/or embossing materials such as in particular plastics, films, non-woven fabrics, woven fabrics/textiles, and/or paper by means of an ultrasonic system. The ultrasonic system comprises at least one resonant unit having a sonotrode and a converter, an ultrasound generator that excites the converter, and an anvil opposite the sonotrode. In order to perform a plurality of at least substantially directly consecutive ultrasonic processing cycles, the impedance of the resonant unit is scanned over a predefinable frequency range by means of the ultrasound generator before the first ultrasonic processing cycle. The present resonance frequency of the resonant unit is determined based on the values obtained by the scanning. The present resonance frequency determined is used as a working frequency for the first ultrasonic processing cycle. The working frequency for the subsequent ultrasonic processing cycles is determined without further impedance scanning on the basis of the working frequency used for the immediately preceding ultrasonic processing cycle in that said working frequency is appropriately adapted by considering the influence of the increasing heating of the sonotrode on the resonance frequency. Alternatively or additionally, the power applied to the converter by the ultrasound generator can also be controlled in an open-loop and/or closed-loop manner between two directly consecutive ultrasonic processing cycles in such a way that the oscillation amplitude of the resonant unit is lowered to a value below the plastification limit of the material to be processed but already assumes a value in the range of said plastification limit at least directly before the subsequent ultrasonic processing cycle. |
