Subsequently, the grinding wheel sequentially grinds the remaining object portions while {HEAD ~ the first wheel head} is returning to {TAIL ~ its home position} 
is returning to
Subsequently , the grinding wheel sequentially grinds the remaining object portions while { HEAD ~ the first wheel head } is returning to { TAIL ~ its home position }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL