In order to study the stability of the unseparated ultrasonic composited milling system

the kinetic characteristics of ultrasonic composited milling are discussed

and the stability model of unseparated ultrasonic milling is established. The semidiscrete method is used to study the stability of ultrasonic composite milling. The numerical analysis was carried out by using MATLAB

and the stability lobe diagram of ultrasonic milling was obtained. Research shows that the stability of ordinary milling system can be promoted by the unseparated ultrasonic milling system and the maximum cutting depth is increased by about 13.8%.The experiment of ultrasonic composited milling was carried out by using titanium alloy material. The correctness of the theoretical model and the stability lobe diagram was verified by the experiment.At the same time

the feasibility of using semi discrete method to analyze the stability of ultrasonic composited milling system is verified.