  The present work deals with determining the necessary parameters considering
a three dimensional model to simulate in a realistic way the turning process on
machine tool. This paper is dedicated to the study of the self-excited
vibrations incidence on various major mechanics characteristics of the system
workpiece / tool / material. The efforts (forces and moments) measurement using
a six components dynamometer confirms the tool tip moments existence. The
fundamental frequency of 190 Hz proves to be common to the tool tip point
displacements, the action application point or at the torque exerted to the
tool tip point. The confrontation of the results concerning displacements and
efforts shows that the applications points of these elements evolve according
to similar ellipses located in quasi identical planes. The large and the small
axes of these ellipses are increasing with the feed rate motion values
accordingly to the mechanical power injected into the system. Conversely, the
respective axes ratios of these ellipses are decreasing functions of the feed
rate while the ratio of these ratios remains constant when the feed rate value
is increasing. In addition, some chip characteristics are given, like the
thickness variations, the width or the hardening phenomenon.
