Powder mixed electric discharge machining is one of the important recent trends in electric discharge machining process which successfully addresses some of the issues associated with the normal die-sinking EDM process. Since the performance of powder mixed EDM is based on work and tool material combination besides other process parameters, various research works have been reported by experimenting with different materials. This work aims to study the influence of different tool materials on powder mixed EDM of a nickel-based superalloy, Nimonic 75, along with using three different powders (zinc, Co and Mo). Nimonic 75 material is being widely used in aerospace and high-temperature applications. Besides the powders type and tool material (Cu, brass and W), the other process parameters are concentration of powder (Cp), peak current (Ip) and pulse on time (Ton). The performance measures considered in this study are material removal rate (MRR), tool wear rate (TWR) and surface roughness (SR). The experiments were conducted based on Taguchi’s orthogonal array (L₂₇ 3¹³). Using ANOVA, it was identified that peak current and tool material had much greater influence over MRR, TWR and SR. Zinc powder yielded highest MRR, and molybdenum powder produced good finish of the components. It was also observed that copper yielded highest MRR, tungsten experienced low TWR, and brass tool electrode produced very smooth surface finish.

粉末混合放电加工是放电加工过程中最近的重要趋势之一，成功地解决了与常规冲模EDM工艺相关的一些问题。由于粉末混合电火花加工的性能是基于工作和工具材料的组合以及其他工艺参数，因此，通过对不同材料的试验，已经进行了各种研究工作。这项工作旨在研究不同工具材料对镍基高温合金Nimonic 75的粉末混合EDM的影响，以及使用三种不同的粉末（锌，钴和钼）的影响。Nimonic 75材料被广泛用于航空航天和高温应用。除了粉末类型和工具材料（铜，黄铜和钨）之外，其他工艺参数还包括粉末浓度（Cp），峰值电流（Ip）和脉冲导通时间（Ton）。本研究中考虑的性能指标是材料去除率（MRR），工具磨损率（TWR）和表面粗糙度（SR）。实验是基于田口的正交阵列（L₂₇ 3 ¹³）。使用方差分析，可以确定峰值电流和工具材料对MRR，TWR和SR的影响更大。锌粉产生最高的MRR，钼粉产生良好的成分光洁度。还可以观察到，铜的MRR最高，钨的TWR低，黄铜的工具电极的表面光洁度非常高。