| 摘要 |
PURPOSE:To aim at enhancing the accuracy of dimensions of an electrode, by forming a cushioning layer on the outer surface of an electric discharge machining electrode, and further by forming a hard insulating film thereover so that useless electric discharge during drilling and grooving is prevented to eliminate the consumption of the electrode. CONSTITUTION:A Cu electrode is generally used as an electric discharge machining electrode 1, and is coated by evaporation with, for example, Mo, Cr or the like in an EB electrodepositing process to form a cushioning layer 2. The speed of evaporation is in a range of 0.5 to 5 A/sec and the film thickness of the layer is in a range of 1,000 to 3,000 A. A hard insulating film 3 is a hard silicon carbide film which is formed by electric discharge of mixture of both DC and CR. The surface of the thus obtained film has a Vickers hardness of 1,500 to 5,000, and the consumption of the electrode is less. Further, it is possible to enhance the machining accuracy of a machined product.
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