Transformations in machining - Part 2. Evaluation of machining quality and detection of chatter in turning by using s-transformation

摘要

S-transformation is proposed to evaluate the quality of completed turning operations. The calculated time-frequency-amplitude plot of an accelerometer or cutting force signal indicates the vibration level at different frequencies and helps the operator to identify the problems. Time-frequency-damping index plots were obtained by using the s-transformation. Variance of damping index in a narrow band around the natural frequency of the workpiece was found as a very descriptive feature of chatter for inspection after machining of a long slender bar. Use of fuzzy logic controllers was proposed for automatic detection of chatter. Integration of the data collection, computation, and dissemination processes by using the local area network is proposed to store the vibration history of machining for critical parts and reporting the results to the operators with wireless devices.