MATERIAL PERSPECTIVE AND CUTTING EDGE RADIUS EFFECT ON ULTRA-PRECISION MACHINING PROCESS

Abstract

In ultra-precision machining, the undeformed chip thickness can be few microns and even approach the nanoscale. At this range, material-related issues are gaining importance due to the microstructural effect on the tool-work interaction phenomena. Thus, based on the material hardness, an innovative technique has been established for the rapid characterization of machined surface. Moreover, the cutting mechanics shifts due to the ‘edge radius effect’ when the undeformed chip thickness (a) drops below the size of tool edge radius (r). A flow stress (σ) model has been developed by correlating the material grain size (d) and chip thickness (tc). Additionally, a novel behavioural chip formation model has been developed for incomplete, perforated and complete chip formations. Finally, ‘burnishing-like’ finishing regime has been identified by appraising the factors of machined surface integrity, compressive flow stress and improvement of nanometric surface finishing for different materials of Al alloy, Mg alloy and Cu alloy.