Acoustic emission monitoring of tool wear during the face milling of steels and aluminium alloys using a fibre optic sensor. Part 1: Energy analysis

Abstract

An investigation of the relationship between tool wear and the energy of acoustic emission (AE) produced during various face milling finishing operations is presented. A model detailing how the AE energy, quantified by the r.m.s. value, varies depending on the material and the detailed tool geometry formed by flank and crater wear is described. Validation of the model was achieved in a series of practical machining tests covering a range of materials and tool types which resulted in various different wear forms. In all these wear tests a non-contact fibre optic interferometer was employed for AE detection directly from the workpiece. This sensor makes absolute, calibrated measurements of AE, unlike conventional contacting piezoelectric AE transducers, which may suffer uncertainties due to their frequency response and variations in transmission path. The fibre optic instrument is thus advantageous for studying variations of AE energy with tool wear.