My creator pro just developed a hitch, when it is starting up, bed appears to move properly once a print would be ready to start it goes to the home position for the X/Y position but then when it moves to the opposite end bed to get ready to drool prior to starting the head will be traveling across the bed (Nozzles not touching the bed) the head will appear to hang up, violent movement as if it is stuck and try to move kind of a grinding noise then continue on to opposite corner. But then my calibrations are off. and the model will not print properly, as it builds a raft it will get to a point "Grind" and continue building the raft in another location. Any ideas?