A first drive unit moves the tool along {HEAD ~ at least two axes} to shape {TAIL ~ the workpiece} similar to a desired surface 
to shape
A first drive unit moves the tool along { HEAD ~ at least two axes } to shape { TAIL ~ the workpiece } similar to a desired surface
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH