Viability and performance assessment of bipolar linear self-servo mechanism-based Maglev electrical discharge machining by processing Al-6062 alloy

Abstract

The enhancement of process efficiency and eradication of basic setbacks of the electrical discharge machining (EDM) process has paved the way for its technological advancement. The discharge irregularities observed during conventional EDM operation due to servo-feedback delay have been addressed by implementing a novel bipolar linear self-servo strategy in Maglev EDM. The paper evaluates the viability of the novel Maglev EDM and analyses its performance in machining aluminum (Al) 6062 alloy. The Maglev EDM uses a systematic combination of magnetic repulsive forces to attain tool positioning in the Z-direction, which serves as the servo gap control mechanism. Experiments were carried out on Al-6062 alloy by utilizing brass tools and surrounding air as dielectric. The voltage–current waveforms exhibited stable and uniform discharges devoid of the short-circuiting and arcing phenomenon. Material removal rate, specific energy, and centerline average surface roughness of 6.717 µg/s, 2.397 J/µg, and 3.735 to 4.507 µm were attained at a discharge power of 16.1 J/s, proving the operational viability of the Maglev EDM. The experimental results were further compared with data available in the previously reported literature. Resolidified layers, globules, lumps of debris, melted debris, micro-pores, micro-voids, micro-cracks, and craters were detected from field emission scanning electron microscopy analysis of the processed work surface. The existence of tool material in the processed surface by energy-dispersive X-ray spectroscopy analysis certified the material migration and surface alloying.