A Grooved Hollow Abrasive Electrode for High-Efficiency Grinding-Aided Electrochemical Discharge Machining of SiCp/Al Metal Matrix Composites

High-reinforcement-fraction SiCp/Al metal matrix composites (MMCs) are difficult to machine efficiently because large, electrically nonconductive reinforcement particles can accumulate in the inter-electrode gap and destabilize discharge and debris evacuation. This study proposes a grooved hollow abrasive electrode for grinding-aided electrochemical discharge machining (G-ECDM). Straight axial grooves are introduced on a hollow abrasive electrode to create enlarged debris-removal pathways without increasing the diamond-grit protrusion beyond the critical discharge gap. Multiphysics simulations and machining observations show that the enlarged pathways redirect electrolyte flow outward, reduce debris residence and local accumulation, and promote the evacuation of large debris particles. Under identical comparison conditions, the proposed electrode achieved a material removal rate (MRR) of 2.14 g/min, compared with 1.41 g/min for the hollow abrasive electrode and 0.07 g/min for the hollow round electrode; the corresponding tool-wear ratio (TWR) was 0.13, compared with 0.28 and 1.01, respectively. Single-factor experiments further show that peak current, pulse width, spindle speed, and flushing pressure affect the trade-off between MRR and tool wear. The results demonstrate that deliberately engineering the debris-evacuation path is an effective means of improving discharge stability and machining performance in G-ECDM of high-reinforcement-fraction SiCp/Al composites.