Electric arc welder performs a given weld process with {HEAD ~ selected current waveform} performed between {TAIL ~ electrode} and workpiece  
performed between
Electric arc welder performs a given weld process with { HEAD ~ selected current waveform } performed between { TAIL ~ electrode } and workpiece
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH