Machining of Ti6Al4V under Cu particle mixed dielectric medium using aluminium composite tool for production of electric motors components

The research investigates the impact of process parameters on the Material Removal Rate (MRR), Tool Wear Rate (TWR),and surface roughness (Ra) of a Titanium alloy under Copper (Cu) mixed Electric Discharge Machining (PMEDM) using anAluminium – 10%graphite (A2) composite tool material. Under optimal conditions of Pon=60 μs, Poff=8 μs, and current=7A,machining with an A2 composite tool achieved an MRR of 0.1 mm³/min, a TWR of 0.0016 mm³/min, and an Ra of 0.847μm. The introduction of 5 g/l of Cu powder into the dielectric fluid minimized TWR to 0.00122 mm³/min, indicating thatthe powder effectively absorbed and dissipated heat, reducing tool wear. At 10 g/l, TWR peaked due to the bridging effect,where particles created a barrier between the tool and workpiece, increasing tool wear. Beyond 10 g/l, TWR decreased due todebris densification, where the particles compacted together, reducing their ability to absorb heat and protect the tool. Surfaceroughness with a minimum Ra of 2.69 μm achieved at 5 g/l, but worsening as the concentration increased, reaching a meanRa of 6.29 μm at 25 g/l. Ra also increased with higher Pon values, peaking at 5.81 μm at 75 μs Pon, indicating that longerpulse-on times allowed more heat to accumulate, leading to greater surface irregularities. Higher currents led to increasedRa, indicating surface quality reduction due to the intense heat generated, which could cause melting and re-deposition ofmaterial on the surface. SEM analysis revealed distinct surface characteristics based on the concentration of Cu powder inthe dielectric fluid. At higher concentrations (25 g/l), the surface exhibited deep pits, craters, and globules, indicating excessiveheat generation and inadequate flushing of machined debris. Lower concentrations (10 g/l) showed reduced pit and cracksizes, with some carbon content deposition from the dielectric fluid. Further reduction to 5 g/l significantly improved surfacequality, with minimal cracks and redeposited material. KCI Citation Count: 0