Real-time drill wear estimation based on spindle motor power

In-process detection of drill wear is one of the most important technologies for unmanned machining systems. This study examines and proposes the method of on-line drill wear estimation based on spindle motor power consumption during the drilling process. Integration of the drilling process model with the spindle drive system model is the key feature of the proposed method. The drilling process model describes the relationship between drill wear and drilling torque, whereas the spindle drive system model describes the relationship between drilling torque applied to motor and spindle motor power. Evaluation tests have shown that the proposed method is a good real-time estimator for drill wear.