Magnetorheological nano-finishing of diamagnetic material using permanent magnets tool

Nano-finishing of a material surface is one of the most required properties in industry. There is high need of nano-finishing of diamagnetic materials such as copper and its alloys in electronic industries and electrode of electric discharge machining. Some industries like laser, aerospace, dentistry and metal optics etc. widely use highly finished copper mirrors. As copper is soft and chemically reactive material, its surface finishing at nano level is a difficult tasked. To fulfill this need, a new magnetorheological technique for precise surface finishing of diamagnetic materials has been conceptualized. Two cylindrical permanent magnets along with magnetorheological polishing fluid have been used to finish the diamagnetic copper alloy workpiece. The cylindrical permanent magnets tool with magnetorheological polishing fluid at its tip surface is rotated over the copper alloy workpiece surface and performs finishing by the stiffened magnetorheological polishing fluid. The permanent magnets finishing tool along with magnetorheological polishing fluid at its tip surface and diamagnetic copper workpiece have been modeled as well as simulated in Maxwell Ansoft V13 (student version) software. Distribution of magnetic flux density in the working gap is obtained and analyzed. Experiments are performed on the copper alloy workpiece and least Ra value of 28.8 nm is achieved in finishing time of 7.5 min from its initial value of 273.6 nm. Surface characteristics of both polished and unpolished workpiece are analyzed with the scanning electron microscopy (SEM) and atomic force microscopy (AFM). The results obtained from finite element analysis and experimentation assures that the new design of magnetorheological finishing tool using permanent magnets is capable to nano-finish of diamagnetic materials such as copper alloy etc.