Electroerosion Resistance Performance of the Electroformed Cu-Graphite Composites

Abstract

Cu—graphite composites, which combine with two kinds of commonly used electro-discharge machining (EDM) electrode materials, were prepared using the co-electroforming technique in an acid sulfate bath. To obtain an optimum combination of copper and graphite in the composites with an excellent electroerosion resistance performance, the effect of electrodeposition conditions, such as graphite bath content, current density, stirring rate, and electrolyte temperature, on the tool-electrode wear were investigated using micro-EDM experiments, and the functional relation of the tool-electrode wear ratio (t) and volume content percent of embedded graphite particles (s) in the composites was further developed. In comparison with the electroformed pure copper, the co-electroformed Cu-20.6vol% graphite EDM macro-scale electrode showed considerably better electroerosion resistance performance, mainly resulting from its optimal volume fraction ratio combination of copper with an excellent heat-transfer character, and graphite with an extremely high melting point, while the UV-LIGA electroformed Cu-20.6vol% graphite micro-feature EDM electrode exhibited much worse electroerosion resistance behavior, primarily owing to its rougher surfaces, lower strength, looser texture, and various deposition drawbacks.