The dynamics of changes in the shape of the surface during abrasive finishing of the precision planes

This article describes the process of a flat abrasive lapping. Considered signs characterizing finishing operation lapping flat surfaces. The processes occurring during lapping, such as mechanical phenomena (microcutting, plastic deformation) and chemical phenomena (formation of oxide films and adsorbed layers). Provides an overview of the most common schemes surfaces forming in the process of lapping. The schemes are considered impulse model, geometric model and energy model of surfaces forming. Based on the energy model and hypotheses Preston found rational law changes downforce during processing, which allows to stabilize the contact pressure and increase productivity. An exponential dependence of the contour area for lapping various planes of the original form macrorelief. An experimental verification of the assumptions and hypotheses Preston at abrasive lapping of samples bronze brand O5С5S5 on flat circles CBN 40/28 50 M2-01 on machine “Raster 220”. It is found that when the efforts change exponentially (similar to the law change the contour of the contact area with the abrasive lapping), process productivity increases of 2.5-3 times. Demonstrated that the change of the standard deviation σ of the roughness parameter Ra of the treated surface during lapping at a constant pressing force, at the beginning of processing (at time t = 1 min), almost two times higher than the standard deviation of the roughness at the same time at a variable force pressing.