Assessment of Tool Wear in Milling Using Acoustic Emission Detected by a Fiber-Optic Interferometer

Acoustic emission (AE) has previously been shown to be a useful technique in monitoring the state of wear of cutting tools. The piezo-electric transducers conventionally used for AE detection are contacting devices with a limited bandwidth. This paper describes the use of a robust fiber optic interferometer for the in-process measurement of AE during the face milling of annealed En24 steel to provide tool wear information via analysis of the rms AE signal. The interferometer displayed an improved diagnostic capability over a conventional piezoelectric sensor due to its advantages of being non-contacting, broadband with a flat frequency response to displacement, and providing absolute calibration.