Calculations for diagnostics of influence of grinding wheel and electric motor unbalance on grinding wheel wear at cylindrical grinding

Abstract

Different aspects of grinding, its stability and arising of self excited vibrations are investigated by many authors. Part of them researched the phenomenon in practice at grinding, the other theoretically and proposed the explanation of grinding stability from different points of view. In our paper successive development of self excited vibrations resulted by initial unbalance of grinding wheel and rotor of electrical motor of a wheel spindle drive is examined. The grinding wheel is dressed in an open loop elastic system of a machine tool while and run-out of its surface according to axis of center pins of grinder is cut off. The grinding is performed in a closed loop elastic system which stiffness differs from an open loop system and it results in some run out of the wheel surface at grinding according to the workpiece. This run out is summing with run out resulted by unbalance of an electrical motor of a wheel drive. Complex periodical oscillations with run out frequencies are excited resulting propagation of the waveness on the workpiece and on the wheel. All it at summing result the impacts in the system which leads to self excited vibrations with natural frequency of some more weak element in a system. Calculation equations are proposed for evaluation of the oscillations and diagnostics of grinding wheel wear.