THERMO-PHYSICAL MODELING OF POWDER MIXED NEAR DRY ELECTRICAL DISCHARGE MACHINING PROCESS

Abstract

Electric discharge machining (EDM) is a widely used non-traditional machining process used in the manufacturing of complex shaped dies, molds, parts used in automobile, aerospace, surgical and other industrial components. The process uses thermal energy of the spark to machine electrically conductive material regardless of their hardness and brittleness. This unique feature of EDM has a distinct advantage in the manufacture of complex shaped die and molds made up of hard materials which are difficult to machine by conventional machining processes. Near dry electric discharge machining (ND-EDM) is advanced method of EDM which is eco- friendly and also more efficient in terms of material removal rate than traditional EDM. In this research an approach has been made to perform a hybrid electrical discharge machining operation on EN-31 steel which utilizes metallic powder as an additive along with dielectric such as air in ND-EDM. This hybrid method of machining is known as Powder mixed near dry EDM (PMND-EDM). This study involves modelling for output process parameter i.e. MRR. The experiments were performed and comparative study has been done between the results obtained by modelling and experiments. The peculiarity of this work is the provision of break down timing in the calculation of heat flux. Moreover, the inclusion of critical concentration ratio into the expression of break-down time provides direct relationship of powder concentration level in the multiphase dielectric mixture with the break down time. It was concluded that the modelling has been done successfully and results obtained do comply with the methodology of the research.