Advanced (Non-traditional) Machining Processes

Abstract

While making a part from raw material, one may require bulk removal of material, forming cavities/holes and finally finishing as per the parts requirements. Many advanced finishing processes have been employed to make circular and/or non-circular cavities and holes in difficult-to-machine materials. Some of the processes employed for hole making are electro-discharge machining, laser beam machining, electron beam machining, shaped tube electro-chemical machining and electro-chemical spark machining. With the demand for stringent technological and functional requirements of the parts from the micro- to nanometre range, ultra-precision finishing processes have evolved to meet the needs of the manufacturing scientists and engineers. The traditional finishing processes of this category have various limitations, for example, complex shapes, miniature sizes, and three-dimensional (3D) parts cannot be processed/finished economically and rapidly by traditional machining/finishing processes. This led to the development of advanced finishing techniques, namely abrasive flow machining, magnetic abrasive finishing, magnetic float polishing, magneto-rheological abrasive finishing and ion beam machining. In all these processes, except ion beam machining, abrasion of the workpiece takes place in a controlled fashion such that the depth of penetration in the workpiece is a small fraction of a micrometre so that the final finish approaches the nano range. The working principles and the applications of some of these processes are discussed in this chapter.