When used to drill ceramic,diamond tools tend to convulse if rotation reaches a certain speed leading to blade failure and tool damage.To fix this problem,three kinds of cutting tools,namely φ24,φ60 and φ90 mm,are experimented to obtain the rotation speed before broken.Resultsshow that the optimum rotation speed increases as the radius of tools increases.It is concluded that for φ24 mm tool,the rotation speed is among 1500 to 1650 r/min,and 1650-1720 r/min and 1700-1800 r/min for φ60 and 90 mm tools separately.Furthermore,properly increasing the infeed speed would enhance the efficiency in condition of reasonable rotation speed.