As {TAIL ~ the substrate} moves over {HEAD ~ the table surface}, it contacts the first and second grinding apparatuses 
As { TAIL ~ the substrate } moves over { HEAD ~ the table surface } , it contacts the first and second grinding apparatuses
OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH