Powder mixed-EDM for potential biomedical applications: A critical review

Powder mixed-electro discharge machining (PM-EDM) is a new emerging trend in research on electro-thermal process that can simultaneously shape and deposit a coating on the surface of the workpiece. PM-EDM is a hybridized form of EDM in which metallic powders are amalgamated in dielectric liquid to enhance both the machined surface condition and machining performance. Migration of materials on the cutting surface occurs by melting and chemical reactions during the operation from both the electrodes and metallic powders. 316L stainless steel, Ti-based alloys, Co-Mo-Cr-based alloys, magnesium and magnesium-based alloys are commonly utilized in manufacturing biomedical devices. These biomaterials, however, release toxic particles due to corrosion, wear, tear, and tiredness of the joint replacements through repeated loads and relative movements. Surfaces of bio-implants made from these biomaterials are therefore protected using bioactive and biocompatible coating. Several methods of deposition are used for coating purposes which have both advantage and drawback. This study proposes that the PM-EDM coating enhances the biomaterials' mechanical characteristics, surface morphology, and topography. Through reflecting critical and analytical concerns, this review focuses extensively on the current progress of the PM-EDM process. Moreover, following various research initiatives, this paper outlines the critical challenges and future research scopes.