Particularities of Plane Surface Lapping

Abstract

Modelling of the lapping process proves a complex undertaking because of the different forms of the abrasive particles in the working area, the wide dispersion of their dimensions, the modifications of their shape and dimensions during processing. The paper proposes the spherical model of the abrasive grain, based on the known fact that a good quality of the processed surfaces requires compact grains, with a dimensional ratio as close as possible to 1:1:1. Based on the adopted model the distribution of tensions at the grain-workpiece contact is determined, as well as the penetration depths of the abrasive grains into the workpiece and the transfer object, respectively. For this certain initial conditions are necessary, like Hertzian contact between the abrasive grain and the processed surface and the neglecting of strain hardening. Taking into consideration the known fact that only the large abrasive grains participate in the actual cutting process while the rest remain suspended in the gap between workpiece and tool, as well as their dimensional distribution and concentration in the lapping slurry, the volume of abrasive material required for processing was determined by statistical methods.