Micro-electrode fabrication processes for micro-EDM drilling and milling: a state-of-the-art review

These days, miniaturized products have a lot of applications in biotechnology, information technology, environmental and medical industries, electric devices, miniaturized machines, and so on. Micro-electrical discharge machining (micro-EDM) is one the most efficient technologies among the nonconventional machining technologies for producing micro-components. Micro-EDM is able to machine tough die materials which cannot be machined by micro-milling. The micro-EDM method has the capability to machine electrical conductive materials with various hardness, strength, and temperature-resistant and complex shapes with accurate dimensions and fine surface roughness. Moreover, it is widely used to produce micro-scale components and structures such as micro-mold, micro-die, micro-probes, micro-tools, fuel nozzles, photo-masks, thin sheet materials, and complex 3D shapes with high accuracy. This paper presents a state-of-the-art review of micro-EDM process as well as the various kinds of micro-electrode and workpiece materials and dielectrics that have been used by previous researchers. In addition, this paper extensively describes and compares various micro-electrode and micro-tool fabrication processes in order to produce precise micro-products. This work is very helpful for the micro-EDM manufacturers and users to select suitable material, dielectric and fabrication processes in researches, and industry applications.