TOOL CONDITION MONITORING BY ACOUSTIC ANALYSIS THROUGH A SOLID PATH

A sensing method using an acoustic signal obtained in a relative low f requency range through a solid path for the monitoring of tool wear ha s been investigated. Such acoustic signals could be in the form of str ess waves that are released during a machining process, which can be p icked up by a regular ferroelectric microphone. Data analysis was cond ucted in both time and frequency domains. A clear pattern in such sign als corresponding to the tool wear conditions has been identified. Sev eral components in spectra were found in the pattern for indicating su dden changes of tool wear or breakage occurring at major cutting edges . It was also observed that the RMS and variance values of the signals could indicate the specific wear condition of the tool. Therefore, th is kind of acoustic signal carries sensitive information about the pro gress of tool wear and can be implemented on line for monitoring tool wear.