“…Although the indirect methods, particularly those based on acoustic emission [6,5,25,23], are quite promising, more research is needed before they can be widely implemented. The cutting-forcebased methods have, on the other hand, more solid theoretical background, and therefore they are more attractive for modeling the metal-cutting processes [3,19,20,7,22,27,17]. It is interesting to note that a combined approach, incorporating an 'intelligent sensor', becomes a new paradigm in metal-cutting-process control [26,31].…”