Temperature Development of Cardboard in Contact with High-frequency Vibrating Metal Surfaces

Albrecht Löwe, Marek Hauptmann, André Hofmann, Jens-Peter Majschak

Abstract


The heating of cardboard was studied when it is in contact with ultrasonic sonotrodes, whose vibrations were orientated parallel and perpendicular to the material surface. The parameters that were varied included the contact pressure on the sonotrode, vibration amplitude, and moisture content of the material. It was shown that there was a major decrease in the contact pressure shortly after the beginning of the experiment when the gap between the sonotrode and anvil was kept constant and thus a decrease in the temperature gradient of the material occurred. With parallel vibration, the material heated up from the sonotrode side, whereas heating started from the center of the material in the case of vertical vibration. This suggested that in cases of vertical vibration, heat is mostly generated by internal dissipation, and in cases of parallel vibration, heat is generated by friction losses on the surface. Furthermore, the results revealed the influence of the parameters on the initial temperature gradient, the maximum temperature, and the moisture content of the material.

Keywords


Paperboard; Ultrasonic vibrations; Heating

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