Spot nanofinishing using ball nose magnetorheological solid rotating core tool

Abstract

The spot nanofinishing of surface plays an important role for improving the surface quality of miniature mechanical, electronics, and optics components. The nano-level finishing of these miniature components is highly demanded in today’s industry to fulfill the operational and functional requirement. The principal innovation of the present work is generating uniform magnetic field at the end of a magnetizable rotating core tool for providing a uniform surface roughness on a spot finishing of precision components. To fulfill this requirement, a ball nose magnetorheological nanofinishing process based on solid rotating core tool is developed. The existing ball end magnetorheological finishing (BEMRF) process uses a rotating core with central hole for flow of polishing fluid at the tool end surface. Due to central hole inside the rotating core, a non-uniform magnetic flux density has been experienced at the tool end surface which may result in non-uniform surface roughness in spot finishing, i.e., on a fixed location without any X-Y-axis linear feed rates. The magnetostatic finite element analysis clearly revealed the uniform magnetic flux density at the end surface of the solid rotating core tool than existing BEMRF tool core having central hole. The experimentation has been carried out for spot finishing on ferromagnetic workpiece surface in order to study the variation in surface roughness values. The present ball nose magnetorheological finishing process with solid rotating core tool produced uniform average surface roughness values as 20 nm from 290 nm after 90 min of spot finishing on the ferromagnetic workpiece surface. The experimental results confirmed the effectiveness of generating uniform magnetic field at the end of a magnetizable rotating core tool for a spot uniform nanofinishing of precision components.