Dedução do incremento das forças de corte dinâmico ortogonal e sua aplicação para previsão da carta de estabilidade, num modelo simplificado de máquina operatriz

Abstract

Presents the theoretical deduction of increment in the thrust and main cutting forces during dynamic orthogonal cutting process for continuous chip, taking iinto account that these forces are functions of two variables, namely the chip thickness and the shear angle. The dynsmic variation of the shear angle is introduced in this deduction. The equations for the prediction of the atability chart are deduced from the increment of forces. A simplified model of machine tool desig:ned with one degree of fredom in the direction of the main cutting velocity and constructed the atability chart and the unconditional stability curve of the model. This curve was compared with the unconditional stability curve, obtained from the exiating equations and with the experimental curve, obtained with the model of machine tool. Making use of the tool holder response, with a degree of fredom in the direction of the thrust force, from reference 13, the two theoretical curves of inconditional atability were again com pared, for the tool holder. Finally, the damping equationfor the prediction as instability was deduced, considering the parameters wich did not appear in the damping equation, deduced by S.A. Tobias16.