Fault phenomenon: A CNC machine tool equipped with FANUC 0MC, model XH754, when the turntable falls after indexing, the movement is obvious and the sound is loud.

Analysis and processing process: The turntable is obviously misaligned when it falls after indexing, indicating that the indexing position of the turntable is quite different from the rat wheel positioning position; if the position is also misaligned when returning to zero, the 4th axis grid offset can be adjusted Use the amount (parameter 0511) to solve the problem: If there is a gap in the turntable transmission, you can adjust the 4th axis gap compensation (parameter 0538); if there is an error in the mechanical pitch, adjust the 4th axis pitch compensation accordingly. In this case, it was found that the turntable also moved incorrectly after returning to zero. The problem was solved after adjusting the value of 0511.