Chapter Eight - Advanced finishing processes

Abstract

Traditional super finishing processes such as lapping, polishing and honing are commonly used for industry, but there are some limitations such as sub-surface damage, residual stress and difficult to finish complex and free form surfaces. But for achieving damage free, nano-level or angstrom level surface finish on difficult to finish materials such as ceramics, glass, silicon wafer, diamond wafer, sapphire wafer etc., and also for finishing complex and free form surfaces with high accuracy, the advanced super finishing processes are very much needed. Various advanced finishing processes, namely Abrasive Flow Finishing (AFF), Chemical Mechanical Polishing (CMP), Elastic Emission Machining (EEM), Magnetic Abrasive Finishing (MAF), Magnetorheological Finishing (MRF) and Plasma Assisted Polishing (PAP) process have been discussed in details. Advanced finishing processes with respect to their working principles, setup details, process parametric effects, advantages and their applications have been discussed. During abrasive flow finishing (AFF) and chemical mechanical polishing (CMP), there is no external control of forces during finishing operation, but nano level surface finish can be generated by control of finishing process parameters. During magnetic abrasive finishing (MAF) and magnetorheological finishing (MRF), there is proper control of forces by externally applied magnetic field and therefore the nano-level finishing of internal and external flat as well as curved surface takes place comparatively at faster rate. For generating atomically flat and damage free surface on optics and semiconductors materials, elastic emission machining (EEM) and plasma assisted polishing (PAP) processes are effectively utilized. Basic working principle, setup details, influence of process parameters, advantages, disadvantages and challenges as well as applications of all those advanced finishing processes have been highlighted. It also emphasizes the recent advancements of those finishing processes.