Acoustic emission monitoring during turning of metal matrix composite and tool wear

Abstract

Acoustic emission testing has been used to monitor machining processes and associated tool wear during machining of silicon carbide dispersed aluminum alloy metal matrix composite with 20% (by weight) silicon carbide. Acoustic emission signals generated during turning operation were acquired for different cutting speeds and temperatures of cutting using a carbide tool. Increasing cutting speed increases acoustic emission and increasing temperature of cutting decreases acoustic emission generation during turning. When increasing the cutting speed from 110 to 600 revolutions per minute at ambient temperatures, the peak amplitude of hits increased from 64 to 85 dB. However, the turning process at all elevated temperatures generated hits of a relatively lower peak amplitude, up to 68 dB. Acoustic emission has also been used to monitor tool wear during turning operation of the composite material. The results indicated that acoustic emission during machining beyond a specific cutting distance increases abruptly and this is attributed to the wear on the tool due to increasing the time of cutting. For the first time, a correlation between the slope (b-parameter) of the amplitude distribution plot of the acoustic emission signals and the flank wear of the cutting tool has been observed and this could be used to monitor the progress in tool wear.