ABRASIVE-BASED NANO-FINISHING TECHNIQUES: AN OVERVIEW

The surface finishing techniques can be divided into two categories: traditional and advanced. To overcome some of the problems of traditional finishing techniques, hybridized processes have been evolved by the researchers. Some of the advanced finishing processes that have been reviewed are abrasive flow machining (AFM), magnetorheological finishing (MRF), magnetorheological abrasive flow finishing (MRAFF), magnetic abrasive finishing (MAF), chemo mechanical polishing (CMP), etc. Most of these processes have been developed in the recent past and they can be employed to produce optical, mechanical, and electronic components with micrometer or sub-micrometer form accuracy and surface roughness within nanometer range with hardly any surface defects. However for large size flat components, MAF seems to be the most suitable finishing process. In MAF, DC power supply is given to the electromagnet hence intermixing of ferromagnetic abrasive particles during the process does not take place and the worn out cutting edges keep interacting with the workpiece surface. As a result, the finishing rate is quite low. The use of pulsed DC power supply to the electromagnet results in pulsating flexible magnetic abrasive brush (P-FMAB), which substantially enhances the finishing rate. The on-line measurement of the forces has helped in understanding the mechanism of material removal during Static-FMAB (S-FMAB) and Pulsating-FMAB. The magnitude of normal magnetic force (originating indentations) in P-FMAB has been found to be dynamic in nature and substantially high in magnitude as compared to S-FMAB.