The quantitative relationship between the discharge power and the machining shape of a workpiece in wire electrical discharge machining (wire EDM) is discussed. The machining gap length is significantly related to the input current under various flushing conditions. We propose a new scheme for predicting the machining shape by monitoring the discharge currents at several positions on the workpiece. This scheme is expected to contribute to the development of a machining shape monitor using in-process wire EDM and to the improvement in straightness accuracy by adjusting subsequent processing conditions for the predicted machining shape.

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While micro electrical discharge machining is gaining greater importance in industry and research circles, there remain persistent difficulties with the handling of the microtool. In this study, we propose the "peeling tool" method to overcome tool handling difficulties. This new method is based on separately coating a micro pin or micro wire electrode with a low melting temperature (LMT) alloy before machining in order to form a thick shank for easy holding. The coated pin electrode is then held in a conventional collet chuck. As machining progresses, the LMT alloy coat is easily melted and the micro pin or the micro wire is peeled effectively for microhole drilling. We discuss the production of peeling tools and their application to microhole machining.

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