An integrated wireless vibration sensing tool holder for milling tool condition monitoring

Tool condition monitoring is especially important in the modern machining process. As one of the basic parameters in the cutting process, cutting vibration is often adopted for the related research. Usually, to measure the vibration, the sensors are mounted on the material workpiece or the machine spindle, which limits the industrial application and brings the low accuracy for the significant physical distance between the sensors and the cutting process. In this article, an integrated wireless vibration sensing tool holder has been developed for tool condition monitoring in the milling process. A standard computer numerical control tool holder is simply modified to integrate sensor for vibration detecting, and related signal conditioning and wireless acquisition circuits are designed. The cutting test proves reliability and stability of the wireless vibration measuring system and shows the clear advantages compared with traditional wired sensors. Eventually, the continuous hidden Markov model (CHMM) has been adopted to diagnose tool wear condition based on vibration signals measured by the developed device. The results indicate that the proposed approach is efficient in tool wear monitoring.