“…The influences of factors such as variation in cutting variables, workpiece composition and tool wear combined with the complex nature of the cutting operation, make the monitoring of milling operation very complex. A lot of research work has been conducted theoretically and experimentally to investigate the effects of these factors on the TCM features and decision making process [1,[10][11][12], but the nature of these influences and their effect on the applied sensors signals has, to a large extent, remained unaccounted for by typical monitoring strategies, as there is no means to measure or detect changes of these factors in FMS [11]. The reliability of TCM system is considerably degraded by the facts that the influences of the cutting parameters and variation of workpiece hardness on TCM features are more significant than that of cutting tool wear.…”