Multi-objective parametric optimization of powder mixed electro-discharge machining using response surface methodology and non-dominated sorting genetic algorithm

Abstract

Powder mixed electro-discharge machining (EDM) is being widely used in modern metal working industry for producing complex cavities in dies and moulds which are otherwise difficult to create by conventional machining route. It has been experimentally demonstrated that the presence of suspended particle in dielectric fluid significantly increases the surface finish and machining efficiency of EDM process. Concentration of powder (silicon) in the dielectric fluid, pulse on time, duty cycle, and peak current are taken as independent variables on which the machining performance was analysed in terms of material removal rate (MRR) and surface roughness (SR). Experiments have been conducted on an EZNC fuzzy logic Die Sinking EDM machine manufactured by Electronica Machine Tools Ltd. India. A copper electrode having diameter of 25 mm is used to cut EN 31 steel for one hour in each trial. Response surface methodology (RSM) is adopted to study the effect of independent variables on responses and develop predictive models. It is desired to obtain optimal parameter setting that aims at decreasing surface roughness along with larger material removal rate. Since the responses are conflicting in nature, it is difficult to obtain a single combination of cutting parameters satisfying both the objectives in any one solution. Therefore, it is essential to explore the optimization landscape to generate the set of dominant solutions. Non-sorted genetic algorithm (NSGA) has been adopted to optimize the responses such that a set of mutually dominant solutions are found over a wide range of machining parameters.

Multi-Objective Parameter Optimization for Cross-Sectional Deformation of Double-Ridged Rectangular Tube in Rotary Draw Bending by Using Response Surface Methodology and NSGA-II

“…Before selecting a decision-maker method, the optimal solution set of multi-objective optimization should be non-dimensionalized. The Euclidian method [16] is utilized to conduct the non-dimensionalization procedure according to Equation (12),…”

A review on machining of metal matrix composites using nanoparticle mixed dielectric in electro-discharge machining

“…Subsequently the work material melts and vaporizes. Figure 1 shows the schematic of EDM where the work-piece is submerged in the dielectric medium with the help of a fixture and the tool is held by the tool holder, being operated by a servo controlled mechanism [4]. The voltmeter, ammeter, and pressure gauge show the readings of potential difference, current flow, and pressure, respectively.…”

“…Sometimes the obtained poor surface finish and machining efficiency restricts the application. To superimpose this problem, the EDM with powder mixed dielectric was used [4]. The spark gap had to be increased by adding up powders in the dielectric fluid so as to reduce the insulating strength, thereby making the process more stable than before and improving the material removal rate (MRR) and surface finish (SF) [5][6][7][8].…”

A study of electrode wear ratio on EDM of Ti-6AL-4V with copper-tungsten electrode

“…EDM is widely being used in innovative manufacturing industry purposely used to transfer material from the work piece by controlling erosion through § a series of electric sparks occurring between the electrode and the work piece immersed in dielectric fluid [5,6]. Generally, EDM produces complex shapes and permits high precision machining of any strong, difficult-tomachine, breakable or thin materials [7].…”