EFFECT OF ORIENTATION OF PRINCIPAL AXISES OF STIFFNESS OF AN ELASTIC-SYSTEM OF THE TOOLHOLDER ON A STABILITY OF TURNING PROCESS

Abstract

Purpose. Research of dynamic quality coefficients of the cantilevered toolholders and definition of directions of heightening of the conditions of chatter stability at turning.

Design/methodology/approach. In a paper it is shown, that essential effect on a level of relative oscillations of the cutter and a workpiece at turning is related with an angle of rotation of principal axises of a stiffness of an elastic-system of the toolholder and selection of the proportions of stiffness of elements of system. Proposed the  theory, which defines conditions of raise of a chatter stability of machining by the nonrigid toolholders and consider a rule of orientation of the principal axises of stiffness of a toolholder in an elastic subsystem of cutter-saddle concerning to a cutting force direction.

Findings. As a result of mathematical simulation the complex mathematical model of the closed dynamic system of a lathe is developed. This model allows to evaluate influence of parameters of the nonrigid toolholders on accuracy of the form of machined surface.

Originality/value. It is shown, that the cutter-saddle elastic-system have the most chatter stability at machining if the angle of rotation of principal axises of a stiffness  of this system is equated to half of angle of a cutting force  direction. On the basis of the results of theoretical and experimental researches the recommendations for designing and a effective using of nonrigid toolholders at turning  are given