ANALYSIS OF TOOL WEAR EFFECT ON CHATTER STABILITY IN TURNING

This study establishes an analytical basis for the prediction of chatt er stability in the turning process in the presence of wear flat on th e tool flank. The components contributing to the forcing function in t he machine vibration dynamics are analyzed in the context of cutting f orce, contact force and Coriolis force. In this way, the effects of th e displaced workpiece volume at the wear flat as well as the workpiece rotation in conjunction with its radial compliance can be incorporate d in describing the motion of the vibration system. Laplace domain ana lysis provides the analytical solution for the limits of stability in terms of the machine characteristics, structural stiffness, cutting st iffness, specific contact force, cutting conditions and cutter geometr y. Stability plots are presented to relate stiffness ratio to cutting velocity in the determination of chatter stability. Machining experime nts at various cutting conditions were conducted to identify the chara cteristic parameters involved in the vibration system and to verify th e analytical stability limits. The extent of tool wear effect and Cori olis effect on the stability of machining is discussed.