Tungsten cemented carbide (WC-Co) is a widely applied material in micro-hole drilling, such as in suction nozzles, injection nozzles, and wire drawing dies, owing to its high wear resistance and hardness. Since the development of wire-electro-discharge grinding (WEDG) technology, the micro-electrical discharge machining (micro-EDM) has been excellent in the process of fabricating micro-holes in WC-Co material. Even though high-quality micro-holes can be drilled by micro-EDM, it is still limited in large-scale production, due to the electrode tool wear caused during the process. In addition, the high cost of precision micro-EDM is also a limitation for WC-Co micro-hole drilling. This study aimed to develop a low-cost desktop micro-EDM system for fabricating micro-holes in tungsten cemented carbide materials. Taking advantage of commercial micro tools in a desktop micro-EDM system, it is possible to reach half the amount of large-scale production of micro-holes. Meanwhile, it is difficult to drill the deep and high aspect ratio micro-holes using conventional micro-EDM, therefore, a cut-side micro-tool shaped for micro-EDM system drilling was exploited in this study. The results show that micro-holes with a diameter of 0.07 mm and thickness of 1.0 mm could be drilled completely by cut-side micro-tools. The roundness of the holes were approximately 0.001 mm and the aspect ratio was close to 15.

This article describes a new hybrid machining process with combination twin-wire electrodischarge grinding (twin-WEDG) and two electrodischarge circuits to produce microelectrode tools rapidly. The results show that transistor and RC electrodischarge circuits could be jointly integrated into micro-EDM to shape microelectrode tools. Compared to conventional single WEDG technology, the twin-WEDG system utilizing both rough and finished machining combined into only one process can reduce machining time by two-thirds and achieve high efficiency when producing microtools. This high-speed microtool fabrication process can be applied not only to micro-electrode machining, but also to micropunching tool and microprobing tips machining.

Due to their hardness and low tool wear, tungsten carbides are widely used in industrial applications, such as spray nozzles, wire drawing dies and spinning nozzles. However, there is no conventional machining process that is capable of fabricating micro-holes, slots and complicated shapes in tungsten carbide. In this study, a low-cost desktop micro electro-chemical machining (ECM) was developed to investigate the characteristics of tungsten carbide micro-hole drilling. The performance parameters of the machining conditions by desktop micro-ECM, such as the machining time, material removal rate, relative tool wear rate, surface quality and dimensional accuracy, were also investigated in this study. The experimental results demonstrate that the low-cost desktop micro-ECM could fabricate micro-holes in the tungsten cemented carbide (WC-Co) workpiece.