Abstract: In-Process Monitoring of wear and breakage states of cutting tools is one of the most important problems to be solved in the unmanned machining process. This paper has first made a detailed analysis about the signal characteristics of milling forces and vibration in both time domain and frequency domain and extracted correspondingly the characteristic parameters from these signals which are very sensitive to variations of milling tool wear and breakage states. Based on this, a multiparameter monitoring strategy which consists of milling force based "Time Section Ratio" monitoring strategy and milling vibration based "Hardware Comparison" monitoring strategy was presented, which has been implemented in a microcomputer APPLE-n centered comprehensive monitoring system and can solve such problems as real time, effectiveness and reliability in the monitoring of wear and breakage states of milling tools.

Key words: in-process monitoring, tool wear, tool breakage, milling force, milling vibration