The Microcontact Analysis of Contact Length between Wheel and Workpiece in Precise Grinding

Abstract

This paper analyzes theoretically the contact length derived from elastic-plastic mechanics and microcontact theory with the aim of improving the traditional method of predicting roughness factor though experiments. The accuracy of the analysis is verified through experiments. It transpires from the theoretical model that the contact length between a grinding wheel and a workpiece increases with decreasing curvature radius of peak, increasing hardness of the workpiece as well as increasing depth of cut. It is also revealed that the contact length is directly proportional to the square of 0.32 of the hardness, approximately, whilst the square root of surface roughness and the density of peak of the grinding wheel show less influence on the contact length. The analysis method has reduced the variation between predicted and experimental values than that of the old methods. These results will be beneficial in analysing and designing the product quality of grinding.

Discrete-element modelling of the grinding contact length combining the wheel-body structure and the surface-topography models

“…However, experimental measurements show that l c is 1.5-3 times larger than l g [2]. The problem of estimation of l c has been tackled from empirical [12,13] and semi-analytical approaches based on Hertz mechanics [14][15][16][17][18] in macro-and micro-scale assuming elastic contact. Lindsay [19] develops a spring model that disregards the depth of cut.…”

“…Some characteristics are shared on these models: the topography [14,17,18], the depth of cut [12,[14][15][16][17][18], the normal force [14][15][16][17][18][19] and the elasticity of the grinding wheel and workpiece [14][15][16][17][18][19]. Only [18] assumes elastoplastic contact, and none considers the effect of the strain-rate, temperature nor cutting. Factors not taken into account are packed into empirical coefficients in all models.…”

A modified model for estimating the contact length in surface grinding

“…Stępień 26 presented an advanced probabilistic model of the grinding process by considering the random arrangement of the grain vertices at the wheel active surface. Horng et al 27 also developed a contact length model by taking into consideration the plastic deformation and the surface roughness. In a recent work, Pombo et al 12 estimated the contact length using thermocouple measurement and numerical simulations.…”