Machining Performance Optimization in End ED Milling and Mechanical Grinding Compound Process

Silicon carbide (SiC) ceramic has been widely used in modern industry for its excellent physical and mechanical properties. However, SiC ceramic is difficult to machine owing to its high hardness and brittleness. This article presents a novel compound process that integrates end electric discharge (ED) milling and mechanical grinding to machine SiC ceramic. The process is able to effectively machine a large surface area on SiC ceramic with a good surface quality. The effect of tool polarity on the machining characteristics such as the material removal rate (MRR), tool wear ratio (TWR), and surface roughness (SR) has been explored. The effects of pulse on-time, pulse off-time, discharge current and open voltage on MRR, TWR, and SR have been investigated with Taguchi experimental design. The experimental data are statistically evaluated by analysis of variance and stepwise regression. The significant machining parameters, the optimal combination levels of machining parameters, and the mathematical models associated with the machining characteristics are obtained. The confirmation experiment results confirm the validity of the used Taguchi method for enhancing the machining performance and optimizing the machining parameters.