As one of the main research fields of intelligent machining technology

monitoring and diagnosis of the cutting tool condition is of great significance to improve manufacturing efficiency and workpiece precision. Herein

the research status of intelligent monitoring of the tool condition is reviewed. The principle and method of the key technologies in intelligent monitoring system including sensor selection

feature extraction and pattern recognition are analyzed in depth. Further

the application status

existing problems and future direction of tool condition monitoring are discussed in details. The progress presented in this paper will be expected to improve the reliability and adaptability of the intelligent condition monitoring system and promote its application in the intelligent manufacturing system.