Investigation and analysis of EDM process – a new approach with Al2O3 nano powder mixed in sunflower oil

Abstract

This study analyses the EDM process of AISI D2 steel with copper tungsten electrode along with Al2O3 powder mixed in sunflower oil as a dielectric fluid in place of EDM oil. AISI D2 steel is predominantly used in the manufacture of precision components of dies, press tools, automobiles, aircraft and space equipment. For that reason, it has been selected as work piece material. Based on the high conductivity nature of electrical and thermal characteristics of copper tungsten, it is used as an electrode in the process. Due to the easy availability and affordability, Al2O3 particles of 60 nano meter size is taken as catalyst for mixing with the sunflower oil and used as an alternate dielectric fluid in place of EDM oil. In order to reduce the harmful effects on the environment produced by the gases due to EDM oil, a vegetable oil namely, sunflower oil is used in its place. Flash point, fire point is higher than 300°C in sunflower oil when compared to conventional EDM oil. It is also eco-friendly and biodegradable. Input parameters of pulse interval, pulse duration, discharge voltage and peak current are compared with various output parameters of the process, namely, electrode wear rate, surface roughness and material removal rate. Experiments are conducted using Taguchi L9 experimental design and the effect of process input values over the output process response are analyzed using ANOVA method. The analysis leads to the conclusion that powder mixed EDM process (PMEDM), in which Al2O3nano particles mixed with sunflower oil yields a minimum surface roughness due to the better heat absorption. More removal of material along with a lesser tool wear is also noticed. Nano particles of Al2O3 improved the surface finish due to the abrasive action of the lowest discharge gap between particles.