Optimization of wire electrical discharge machining parameters for cutting electrically conductive boron carbide

Abstract

In this work, Pure boron carbide (B4C) was consolidated using spark plasma sintering (SPS) at 2050°C with a dwell of 10min under 50MPa uniaxial pressure in Argon atmosphere. The sintered specimen was >99% dense and offered characteristic Vickers hardness and fracture toughness of 31.4GPa and 4.21MPa-m0.5, respectively, at 4.9N indentation load. The specimen showed satisfactory wire electrical discharge machining (WEDM) performance because of its good electrical conductivity. The design of experiment (DOE) was arranged by L32 orthogonal array (OA) between the machining input parameters namely pulse on-time, pulse off-time, pulse peak current, dielectric fluid pressure and servo feed rate and the output responses like machining speed and surface roughness (Ra). Regression models were employed to establish the numerical correlation between the machining parameters and output responses. Experimental observations were utilized to formulate the first-order regression models to predict responses of WEDM. The optimized input parameters were 27 μs pulse on time, 48 μs pulse off time, 180A pulse peak current, 7kg/cm2 water pressure and 2200mm/min servo feed rate for the WEDM performance to produce an optimum machining speed and Ra.