A grinding force model considering the arc-track feeding unit device in ELID grinding of the non-standard ultra-precision bearings

Abstract

Bearings play an important role in the national defense industry. The demands for the ultra-precision non-standard bearings are increasing year by year. Correspondingly, the requirements for the surface roughness of bearing raceways are getting higher and higher. The surface roughness Ra value of the bearing groove raceway has been significantly improved by the ELID (Electrolytic In-Process Dressing) grinding assisted by the arc-track feeding unit. In this research, a grinding force model for the ELID groove grinding assisted by the arc-track feeding unit is established. The modelling of the swing speeds, swing angles and duty ratios of the arc-track feeding unit are carried out as the basis for the predicting of the tangential and the normal forces. For the first time, the equivalent elastic modules are used to characterize the variation of the ELID oxide layer in the new model. Validated by the linear-groove ELID grinding with varying swing speeds, swing angles and duty ratios of the arc-track feeding unit, the predicting results of the force capture well the fluctuation of different force components due to the changing of the variables. The new grinding force model involving the arc-track feeding device is able to give accurate predictions to the tangential and normal forces. The maximum error between the predicting tangential forces and the experimental tangential force is 5 %; the maximum error between the predicting normal forces and the experimental normal forces is 6.2 %. It provides an insight into the material removal mechanism and the grinding force characteristics in the ELID grinding assisted by the arc-track feeding unit for further improving the forming accuracy of this new method.