Recently we’ve had a print failure where the print head dropped down in the middle of a print, crashed into the part and broke both the hot ends on the volcano extruders.
Here are a few steps we took to diagnose the problem.
Inspect the part to see if it the corners are warped. If the part lifts off the bed, it gets caught in the hot end and may cause the hot end to shear off.
Open the g-code file in the software and check to make sure there are no errors in it. If you know the exact layer at which the print failed, search for it (In Notepad) in the g-code and make sure the Z height is increasing as it moves on to the next layer.
Z motor issues
Using the controls on the board, move the Z axis to make sure it follows the “Move” commands correctly.
Remove the cover and inspect the couplings to make sure there are intact. Also, make sure the set screws on the couplings are tightened.