Experimental Investigation of Silicon Powder Mixed EDM Using Graphene and CNT Nano Particle Coated Electrodes

Abstract

Nano-coating on electrodes is a new technique to enhance the machinability of difficult-to-machine alloys during Electrical Discharge Machining (EDM). The current investigation seeks to propose a comparative study of nano-particle coated and conventional electrodes during EDM process with an extended objective to machine in WEDM process. The current work seeks to propose a new experimental technique to improve the machinability of difficult-to-machine materials during EDM process by making use of nano-coated electrode considering silicon powder mixed deionised water and hence extend its application in WEDM process. The present study is focused to improve the machining performance of EDM using graphene (rGO) and carbon nano tubes (CNT) nano-coated brass electrodes. A 6–8 μm coating thickness is used for the comparative analysis. The present study considers Inconel 825 as the workpiece material. The experiments were conducted under identical operating conditions as WEDM process by using deionised water as dielectric to extend the study further for nano-coating of brass wires. Silicon powder with a concentration of 4gl was mixed into the dielectric to enhance the quality of the machining process. Grey relational analysis (GRA) and technique for order preference by similarity to ideal solution method (TOPSIS) facilitates determining the optimum input parameters. Voltage = 100 V, Peak current = 9A and Pulse on time = 100 μs was found to be the optimum condition from both GRA and TOPSIS. From the present analysis, an improvement of 16.9% (MRR), 25.59% (EWR) and 14.29% (Sa) was found in case of rGO. Whereas, CNT showed a better improvement of 30.6% (MRR), 29.50% (EWR) and 16.68% (Sa) compared to rGO.