Abstract Bulk metallic glass (BMG) is a new class of material discovered in recent years with prospective applications in space, nuclear reactor engineering, biomedical, and electronics industries. Metallic glasses are difficult to be machined using conventional machining processes due to the extreme hardness and non-crystalline/amorphous structure of metallic glass. Therefore, this study aims to investigate the machinability of metallic glass using a non-contact based process, called micro electro-discharge machining (micro-EDM). The crater sizes and overcut of the micro-holes on metallic glass were evaluated at different settings of machining parameters. In order to minimize the position error and improve machining accuracy, the electrodes were machined in-situ using block micro-EDM process. In this study, the capacitance was found to be the main parameter influencing the machining performance among all the possible factors. It was found that the crater sizes mostly depended on the values of capacitances, with minor influence of voltage. When compared against the discharge energy, the crater size followed an excellent trend. It was found that micro-EDM was able to generate crater sizes as small as 2.2 µm. However, the recast layer around the edges of micro-holes increased significantly with the increase of capacitances and voltages. In addition, a minor effect of electrode size on the surface finish and overcut were found. The finite element method (FEM) modeling of the craters formed during the micro-EDM of metallic glass showed various phases in a single crater including molten layer followed by a crystalline layer. The developed model was able to successfully predict the crater sizes, as the experimental crater sizes matched closely with those predicted by the FEM simulation.
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