IJPEM-GT

Chatter Detection and Identification in High-Efficient Robotic Milling CFRP Composites Using Acoustic Emission Technique

Maojun Li/Hunan University

Keywords : Stability Robotic milling Acoustic emission Stability lobe diagram
Industrial robots are preferred to be applied for machining lightweight, thin-walled and large aerospace composite components due to less energy consumption and flood coolant pollution, easier setup and portability compared to heavy machining centers. However, chatter is the main concern as robots present considerably lower stiffness than machine tools. This paper reported the first demonstration of applying acoustic emission (AE) technique to analyze chatter using short-time Fourier transform, fast Fourier transform and wavelet packet decomposition methods during high-speed robotic milling of CFRP composites for aerospace applications. The stability lobe diagram and surface topography were further investigated to verify chatter phenomenon. It was interesting to find that the energy distribution of decomposition components of acoustic emission signals and the maximum amplitude of AE data gradually concentrated from the tooth passing frequency to the rotation frequency of milling cutter when increasing spindle speed. The significant changes in maximum amplitude in frequency domain after 2500 low-pass filtered and surface topography clearly characterized the incidence of chatter. The stable operating zone indicated in the stability lobe diagram was validated by experimental results.