| Summary: | 博士 === 國立中央大學 === 機械工程研究所 === 87 === The increasing demand for new lightweight materials with greater strength and toughness has led to the development of a new generation of composite materials in the recent decade, even though these same properties create major challenges for machining. Although possessing a greater hardness and reinforcement strength, composite materials cause serious tool wear when traditional machining is used. Nontraditional machining techniques such as laser machining, electrical discharge machining process, conclusively becomes a proper tool. However, the EDM wire-cut process is barely applicable for the MMC workpiece due to excessive breakage of the electrode wire. Furthermore, it is too expensive to use laser machining which is unsuitable in complex shape of workpiece. Experimental results concludes that rotary EDM with either a disk-like electrode, or a tube electrode as well as a electrode with ball burnishing, is a feasible technique to slit or drill for MMC, respectively. In addition, this improved machining method of the MMC materials is considered to be among the most essential methods in manufacturing industries.
The material removal rate, electrode wear rate, and surface roughness are connected with several factors and levels which are related to EDM conditions. In this experiment shows six factors, including electrical discharge factors, i. e. polarity, peak current, pulse duration, and non-load voltage, and non-electrical discharge factors, i. e. rotational speed of electrode, and flushing pressure of dielectric. The Taguchi method is efficiently to determine the optimum conditions for obtaining a higher material removal rate, a lower electrode wear rate, and a finer surface roughness, respectively.
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