Theoretical and Experimental Investigation on Microcosmic Surface Generation in Precision Grinding with Discrete Method

Abstract

Surface topography of the workpiece created in precision grinding is influenced by not only key process parameters, but also the distribution characteristics of active abrasive grits on the surface of the grinding wheel, including the number of active grits in the contact zone, the morphology of grits, and the cutting depth of a single grit in a normal direction. Under the conditions of small cutting depth (less than 5 µm) with small eccentrical rotation of the abrasive wheel (less than 3 µm), the influences of the original workpiece surface topography characteristics and the dynamic cutting depth of abrasive grits are often neglected in the study of microcosmic surface generation. In this paper, a discrete method (DM) is used to develop a theoretical kinematics model for the prediction of machined workpiece surface topography. Compared with the characteristics value of surface topography (scratch grooves) between experimental measurement and simulation output, the verification results from the improved prediction model of surface topography present well in comprehensively considering the influences of original surface characteristics, eccentrically rotational behavior of the abrasive wheel and the overlapped situation of scratch grooves on complex process conditions with a prediction error of about 10 %. In comparison with two commonly used empirical formulas in many other research studies, the prediction accuracy of the DM model for machined surface topography improves by 20 %. When calculating material removal volume, the prediction accuracy of incremental volume model of material removal increases approximately by 9 % to 19 % in comparison with the prediction results that take the whole cross-section area of an active grit as a key variable.