This paper describes a new hybrid micro-machining method, which combines wire electro discharge grinding technology with one pulse electro discharge, to fabricate micro-spherical probes and micro-spherical cavities. The results show that a burnished micro-spherical probe with about 40 µm diameter could be formed instantaneously with the hybrid machining process, which is not available in the conventional micro-machining method. The deviation in diameter and roundness tolerances of micro-spherical probes is about 1 µm and 3 µm, respectively. Compared with conventional electro discharge machining, the surface roughness of the spherical probe is much smaller than a discharge crater. It will be possible to achieve more accurate three-dimensional measurements with the micro-spherical probe attached to the coordinate measuring machine in the future.

This study describes the use of micro electro-discharge machining (m-EDM) scanning technology to fabricate micro three-dimensional cavities and microtools fabrication on polycrystalline diamonds (PCD). The experimental results show that short-pulse discharge from an resistor-capacitor (RC) circuit is more effective and precise than a transistor (Tr) pulse generator while machining PCDs by m-EDM. The surface roughness of PCD using the m-EDM scanning process could be as small as Ra 0.2 mm, even when the diamond grain size is considerably larger. Moreover, small PCD tools for cutting brittle materials could be easily fabricated by the same m-EDM process. Thanks to their hardness and excellent thermal conductivity, PCDs could be utilized in the near future, not only for micro molds, but also for tools to cut brittle material.

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This paper describes an on-machine measurement function of a micro electro-discharge machine (μ-EDM) to evaluate the quality of micro ball-ended stylus tips fabricated by a combination of wire-electro-discharge grinding (WEDG) and one-pulse-electro-discharge (OPED) technology. A low-voltage contacting trigger function without any capacitor between a stationary wire and the spindle of a μ-EDM was used to measure the outer profile and evaluate the forming quality. The measurement results show that the deviation of the largest radius between the micro ball-ended tip and stem is approximately 3 μm. Moreover, OPED/WEDG is also easily able to produce high-quality micro spherical stylus tips with a standard deviation as small as 0.7 μm through use of sharp-needle-shaped electrode tools. With further improvements in electro-discharge position, OPED and WEDG technology are promising and excellent approaches for manufacturing micro coordinate measurement machine (CMM) spherical stylus tips.

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This paper describes a new machining process which combines twin-electro-wire together with two electro discharge circuits to rapidly fabricate micro electrode tools. The results show that transistor electro discharge and RC electro discharge circuits coexist to fabricate micro tools with rough and finish machining both on the same machine. Compared to conventional wire electro discharge grinding (WEDG) technology, a twin-wire EDM system that combines rough and finish machining into one process allows the efficient fabrication of micro tools. This high-speed micro tool fabrication process can be applied not only to micro electrode machining but also to micro punching tool and micro probing tips machining.

In this paper the assembly of a novel micro-scale coordinate measuring machine (CMM) probe is considered. A working micro-scale CMM probe is assembled from a MEMS device and a stylus produced by micro-electro-discharge machining. The production technique of the micro-scale parts is discussed and two methods for assembly are presented.

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.