Parametric optimization of wire-EDM machining of nimonic 80a using response surface methodology

Abstract

Wire electrical discharge machining (WEDM) can machine hard materials with ease. Nimonic 80A is hard and high temperature resistant material which is widely used in the power plant boiler tubes, gas turbines, exhaust valves. This work involves in developing a models for correlating the dependency of various WEDM process parameters of Nimonic 80A like gap voltage, duty factor and feed rate on response factors like rate of material removal (MRR), wire wear ratio and surface roughness (SR). This experiment was carried out on the basis of Response Surface Methodology (RSM) and Grey Relational Analysis (GRA). Using the design of experiments, 20 experiments were conducted. The duty factor of 0.8771, gap voltage 17V and wire feed rate of 17m/min was found to be the optimized process parameter while machining Nimonic 80A.

Experimental study on wire electric discharge machining of nimonic 90 using coated electrode

“…Nimonic has properties i.e., resistance to oxidation and corrosion at elevated temperatures which makes it more suitable in manufacturing turbine parts (blades), exhaust nozzles of jet engines, valves of auto industries, bolts, supports, and cores of nuclear plants [5]. Nimonic work hardening ability causes wear out the tool, its low thermal diffusion causes more heat generation at the tip of the tool, continuous chips are resisted and chips get stuck on the cutting edges, this makes Nimonic challenging to machine on conventional machines [6]. Among Unconventional machines Wire-EDM is used for about 33%, EDM is used for 30%, 15% by Electrochemical Machining, and a very small percentage of machining is done using other unconventional machines for machining of Nickel superalloys [7].…”