Improvement of surface quality of INCONEL 718 in EDM machining using MRSN and utility method

Abstract

Electro-Discharge Machining is a popular nonconventional machining process used to make dies of different shapes in any conducting materials irrespective of the hardness and strength of the workpiece materials. INCONEL 718 is a harder material used for making dies and other applications in automobile, aerospace and nuclear sectors. For long life of a die, it should have high wear resistant properties with crack free surface. In the present work, INCONEL 718 workpiece material is machined by EDM using a copper tool by varying input current, pulse on time, pulse off time and flushing pressure according to Taguchi’s orthogonal array to economically carry out experimental work. Four output parameters such as: surface roughness, crackwidth, surface crack density and hardness are optimized simultaneously using two most popular multi-response optimization techniques such as: Multi-response signal to noise ratio (MRSN) and Utility method. A better optimization technique is reported based on the value of signal to noise ratio. ANOVA technique is also used to report the most effective input parameter. Finally, a confirmation test is carried out and the utility method is proved to be the better optimization technique to have minimum loss to the society. This technique can also be extended for other process optimization and helpful for industry personnel to select appropriate process parameters for making a die of long life.