forming {TAIL ~ a cavity} in {HEAD ~ the root portion} of at least one single crystal superalloy blade 
forming { TAIL ~ a cavity } in { HEAD ~ the root portion } of at least one single crystal superalloy blade
OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH