Study on self-sharpening mechanism of porous diamond abrasive grain based on discrete element simulation

Porous diamond abrasive grains, a newly developed type of abrasive grain for ultra-precision machining, show considerable potential for future applications due to their unique pore structure. However, the mechanisms underlying their self-sharpening behavior remain unclear. In addition, few studies have addressed the effects of pore geometry and grinding parameters on self-sharpening performance. To address this gap, this study proposes a discrete element method (DEM)-based model to simulate the abrasive wear process of porous diamond grains under various pore and grinding conditions. The model captures the dynamic evolution of wear and reveals its effect on self-sharpening behavior. The simulation results elucidate the mechanisms of grain wear, crack propagation, and self-sharpening. The findings show that the presence of pores helps reduce grinding-induced damage. Under a fixed pore size of 5 μm, increasing pore density enhances self-sharpening performance. However, inappropriate grinding parameters—whether insufficient or excessive—can hinder self-sharpening, leading to extensive damage and chipping. To achieve stable self-sharpening, the undeformed chip thickness should be maintained at 1 μm, and prolonged high-speed grinding (wheel speed exceeding 70 m/s) should be avoided.