Improved approach to magnetorheological finishing of blind-hole cavities

Abstract

Nanofinishing of blind-hole cavities is important to produce high quality products without any surface irregularities. The commonly used methods such as grinding or honing are not efficient because of the uncontrolled forces and direct contact of the solid abrasive tool with the workpiece. Magnetorheological (MR) polishing process using smart fluid has proved its effectiveness in achieving the nano-finished surface. The existing tool design uses two different operations for nano-scale finishing of a blind-hole cavity, resulting into a higher production cost. In this present work, a novel tool that can vary its dimensions during finishing operation was developed for enhancing the surface finishing of blind-hole cavities. Distribution of magnetic fields within the entire tool and blind-hole cavity surface was found appropriate and also revealed that the tool surface has maximum magnetic field for stiffening the MR polishing fluid over its surface. After 90 minutes of finishing, it was concluded that the roughness (Ra) change on the blind-hole cavity were reduced by 75.12% (on inner vertical) and 74.21% (on inner bottom).