Air is conveyed onto the engraving work surface to cool the workpiece and reduce {HEAD ~ the possibility} of {TAIL ~ fire} 
of
Air is conveyed onto the engraving work surface to cool the workpiece and reduce { HEAD ~ the possibility } of { TAIL ~ fire }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL