{HEAD ~ The material web} is guided through a gap between the sonotrode and the counter tool and acted upon by {TAIL ~ the sonotrode} 
acted upon by
{ HEAD ~ The material web } is guided through a gap between the sonotrode and the counter tool and acted upon by { TAIL ~ the sonotrode }
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL