Experimental Investigation and Mathematical Modeling for Material Removal and Tool Wear in Making of Rectangular Channels by Electric Discharge Machining (EDM) on Aluminum–Boron Carbide Composite Sintered Preform

Abstract

Boron carbide (B4C) particulate Aluminum (Al) metal matrix composites (MMCs) are highly demanded due to their specific strength in aerospace, defense, and nuclear sectors. The controllable porosity which causes the good toughness and the forming limit values can be obtained for these MMCs synthesized by powder metallurgy route. But the porosity level had great influence on the machinability of these MMCs by electric discharge machining (EDM). In the present work, cold compaction followed by sintering of Al and B4C powders was used to fabricate the MMC specimen. The density and hardness were estimated by Archimedes principle and Vickers microhardness test, respectively. The feasibility of EDM of the fabricated MMC at high porosity level (12%) was evaluated through pilot experimental runs. The full factorial experimental design with three parameters of three levels each (total runs 33 = 27) is used for experimentation. The influence of electrical process conditions such as discharge current (I), pulse-on duration (T-On), and pulse-off duration (T-Off) on material removal rate (MRR) and tool wear rate (TWR) was studied. A mathematical model was formulated to represent the process. Analysis of variance (ANOVA) was performed to identify the significant parameters affecting the material removal rate (MRR) and tool wear rate (TWR). Results revealed that the developed model was adequate to represent the process with R-square values of 94.9%, and 83.82% for MRR and TWR, respectively. Results also showed that the discharge current had a significant effect on the MRR and TWR.