Surface modifications of biomaterials play a vital role in matching the complexities of the biological system and improving the performance of bioimplants. Suitably customised surface modifications can substantially enhance the relation of material towards biocompatibility, bondability and host cells associations. In addition, materials surface engineering accelerates the progression and configuration of next-generation biomaterials and restorative gadgets. This review article dedicates to the surface modification techniques of several essential metallic biomaterials, viz. stainless steel, magnesium, titanium and chromium–cobalt. It presents the unique novel futuristic method of surface modification via electrical discharge machining (EDM) process which still awaits to prove its potential in the biomedical domain. Previously established research work on this nonconventional machining process elucidates that an adequate surface integrity can be achieved by control of crucial EDM process parameters such as pulse on, pulse off, current, polarity, dielectric medium and tool electrodes. Therefore, there is ample scope for the EDM process in examining the issues related to the synthesis and precise shaping of the bioimplants.

The present article focused on the surface characterization of electric discharge machined duplex stainless steel (DSS-2205) alloy with three variants of electrode material (Graphite, Copper-Tungsten and Tungsten electrodes). Experimentation was executed as per Taguchi L18 orthogonal array to inspect the influence of electric discharge machining (EDM) parameters on the material removal rate and surface roughness. The results revealed that the discharge current (contribution: 45.10%), dielectric medium (contribution: 18.24%) majorly affects the material removal rate, whereas electrode material (contribution: 38.72%), pulse-on-time (contribution: 26.11%) were the significant parameters affecting the surface roughness. The machined surface at high spark energy in EDM oil portrayed porosity, oxides formation, and intermetallic compounds. Moreover, a pin-on-disc wear analysis was executed and the machined surface exhibits 70% superior wear resistance compared to the un-machined sample. The surface thus produced also exhibited improved surface wettability responses. The outcomes depict that EDMed DSS alloy can be considered in the different biomedical and industrial applications.

Electrical discharge machining (EDM) is a highly precise technology that not only facilitates the machining of components into desired shapes but also enables the alteration of the physical and chemical properties of workpieces. The complexity of the process is due to a number of regulating factors such as the material of the workpiece and tools, dielectric medium, and other process parameters. Based on the material type, electrode shape, and process configuration, various shapes and degrees of accuracy can be generated. The study of erosion is based on research into processing techniques, which are the primary tools for using EDM. Empirical knowledge with subsequent optimization of technological parameters is one of the ways to obtain the required surface quality of the workpiece with defect minimization, as well as mathematical and numerical modeling of the EDM process. This article critically examines all key aspects of EDM, reflecting both the early foundations of electrical erosion and the current state of the industry, noting the current trends towards the transition of EDM to the 5.0 industry zone in terms of safety and minimizing the impact of the process on the environment.

With increasing popularity of Electrical Discharge Machining (EDM) method upon part manufacturing precision with tailorable surface properties; the assessment of EDM process was therefore carried out concerning the surface alteration of medical grade Co-Cr alloy biomaterials. The samples surface were EDMed at different spark energy levels by varying current and On-time to investigate the surface characteristics, and it's biological responses. MTT assay and cytocompatibility test were conducted to examine the in-vitro biocompatibility confirming the higher competent cell viability and proficient RBC lysis for the surface treated with spark energy ranging from 960J–1500J. Here the experimental results revealed that application of low-current (5 A) and high On-time (200 µs) favors the synthesis of high-quality biocompatible substrates. Thus, surface modification of Co-Cr implants using EDM can be considered as a promising method for improving surface properties essential for biomedical applications.