Optimization of Process Parameters Using Soft Computing Techniques: A Case With Wire Electrical Discharge Machining

Optimization of Process Parameters Using Soft Computing Techniques: A Case With Wire Electrical Discharge Machining

Supriyo Roy (Birla Institute of Technology, India), Kaushik Kumar (Birla Institute of Technology, India) and J. Paulo Davim (University of Aveiro, Portugal)
DOI: 10.4018/978-1-5225-2128-0.ch006

Abstract

Machining of hard metals and alloys using Conventional machining involves increased demand of time, energy and cost. It causes tool wear resulting in loss of quality of the product. Non-conventional machining, on the other hand produces product with minimum time and at desired level of accuracy. In the present study, EN19 steel was machined using CNC Wire Electrical discharge machining with pre-defined process parameters. Material Removal Rate and Surface roughness were considered as responses for this study. The present optimization problem is single and as well as multi-response. Considering the complexities of this present problem, experimental data were generated and the results were analyzed by using Taguchi, Grey Relational Analysis and Weighted Principal Component Analysis under soft computing approach. Responses variances with the variation of process parameters were thoroughly studied and analyzed; also ‘best optimal values' were identified. The result shows an improvement in responses from mean to optimal values of process parameters.
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Introduction

Requests for deciding items have turned out to be progressively perplexing as clients expect improved execution over an assortment of differing and changing framework working conditions. Reconfigurable frameworks are having the limit and usefulness keeping in mind the end goal to meet complex destinations and capacity viably in changing working conditions with competent to convey esteem in element economic situations. They are intended to keep up an abnormal state of execution by changing their design to meet the numerous capacity necessities or a change in working conditions inside worthy reconfiguration time and cost.

Wire Electrical discharge machining (WEDM) is a non-traditional, thermo-electric procedure which disintegrates material from the work piece by a progression of discrete sparkles between a work and instrument terminal submerged in a fluid dielectric medium. Schematic representation is represented underneath in Figure 1.

Figure 1.

Schematic representation of Wire EDM process

978-1-5225-2128-0.ch006.f01

These electrical discharges melt and vaporize minute amounts of the work material, which are then ejected and flushed away by the dielectric (Tosun et al. 2004, Tosun and Cogun 2003). A wire of diameter ranging from 0.05 to 0.25 mm is used as the tool electrode (Kozak et al. 1994). The wire is persistently supplied from the supply spool through the work-piece, which is clasped on the table by the wire footing rollers. A crevice of 0.025 to 0.05 mm is kept up always between the wire and work-piece (Spedding and Wang 1997a). The wires once utilized can't be reused because of the variety in dimensional exactness (Scott et al. 1991). Recently, WEDM is being used to perform machining operation on a wide variety of miniature and micro-parts made of metals, alloys, sintered materials, cemented carbides, ceramics and silicon (Muttamara et al. 2003, Mohri et al. 2002, Weng and Her 2002, Yeo and Yap 2001 etc.). Here, investigation of optimum combination of machining process parameters for large value of MRR and minimum value of surface roughness were carried out by using soft computing techniques like Taguchi Analysis, Grey Analysis and Weighted Principal Component Analysis. Sensitivity analysis is proposed to show the efficacy of one method over other methods.

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Literature Review

Wire electrical release machining (WEDM) is the second most prominent non-customary machining process, after EDM, broadly utilized for producing part of the aviation, vehicles and therapeutic commercial enterprises and in addition in essentially all territories of conductive material machining. In this procedure, material is disintegrated from the work-piece by a progression of release sparkle between the work-piece and wire cathode isolated by a dainty film of dielectric liquid which is consistently introduced to the machining zone to flush away the dissolved particles. As a fundamental prerequisite, the machining operation ought to create the product with least time and at wanted level of surface texture. Machining time is subject to the material removal rate (communicated in mass per unit time and also volume per unit time) of the procedure. For mechanical practice, MRR ought to be greatest from financial perspective. Then again, surface texture or roughness assumes a vital part for the tribological operation of any segment. It has substantial effect on the mechanical properties like fatigue behavior, corrosion resistance, creep life and so forth. It additionally influences other useful characteristics of machine parts like friction, wear, light reflection, heat transmission, lubrication, electrical conductivity and so on.

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