Early chatter detection in gear grinding process using servo feed motor current.

Monitoring and early detection of chatter are the key techniques to avoid the harmful effects caused by chatter in manufacturing process. The key for early chatter detection is to capture the feature signatures. A convenient and reliable technique is presented in this study to detect chatter in gear grinding process based on servo feed motor current and wavelet packet transform. Wavelet packet transform was used to monitor the energy change in the frequency domain and to identify the feature frequency band with respect to chatter, the result of which was confirmed by the impact hammer test. Standard deviation and energy ratio of the feature frequency band signal were chosen as the indexes of chatter monitoring. Combining these two chatter features, the state of the grinding process could be classified and chatter could be detected reliably in industrial application with proper thresholds. Acceleration signals of the machine tool were used as a reference to compare with the results from current signals. In every stage of the grinding process, the feature frequency band signals of current and vibration signal have shown very coincident variation trend. Both theoretical analysis and experimental results manifested the feasibility and efficiency of the proposed method. [ABSTRACT FROM AUTHOR]