International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395-0056
Volume: 11 Issue: 04 | Apr 2024
p-ISSN: 2395-0072
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Performance Study of Electrochemical Micromachining of Al7075/Al2o3 Composite A.Hussain Lal1*, S.Sakthi1, G.Surendar1, A.Muthusamy1 1Department of Mechanical Engineering, Arifa Institute of Technology, Esanoor,
611103, Tamilnadu, India. --------------------------------------------------------------------------***--------------------------------------------------------------------------
ABSTRACT-Micromachining domain requires machining techniques that would fulfill the severe demands like machining
quality, higher machining rate, dimensional accuracy, economy and so on. Among the many available non-conventional machining methods electrochemical machining is under continuous research to adopt it on commercial scale to fulfill the industry-specific applications. Al7075, a heat treatable alloy is widely employed for structural components in automotive and aero-space industries. Composites are made out of Al7075 alloy to enhance its properties by reinforcing with appropriate ceramic compounds. This study examines the applicability of electrochemical micromachining (EMM) to Al2O3 added Al7075 composite. The process input factors investigated are voltage, duty cycle and electrolyte concentration and the performance analyzed through responses such as machining rate (MR) and radial overcut (ROC). Taguchi’s L9 design is used for experimental investigation to find the effect of process parameters and also carry out single-response as well as TOPSIS optimization. Electrolyte concentration was found to be the dominant parameter on the process. The TOPSIS method yielded the parametric combination of 12V, duty cycle of 70% and NaNO3 concentration of 40 g/lit to achieve higher MR and lower ROC. Keywords: Electrochemical micromachining; Al7075/ Al2O3 composite; machining rate; radial overcut; Taguchi; TOPSIS
1. INTRODUCTION As an energy saving measure and to make the structures light-weight, structural components in many industries are now made with lighter materials like aluminium alloys instead of using heavier materials. Al7075 alloys particularly find application in automobile, aero and mobile industries to exploit their superior mechanical properties [1]. Still these lightweight materials like Al7075 are found deficient to certain extent like in hardness and tensile strength which can be enhanced by reinforcing hard ceramic particles into the such as Al2O3 and others into the matrix of the alloy in an uniform manner [2]. The capability of electrochemical micromachining process is tested through experimentation for different materials like pure metals, alloys and composites, different electrolytes and also applying various input conditions and approaches. Nimonic 75 alloy used in aero industry has been machined under EMM successfully using acidified electrolyte and un-acidified electrolyte (NaNO3+NaCl). The un-acidified electrolyte provided better performance and the parameters have been optimized using Topsis technique [3].Micro-circular impressions have been generated on stainless steel work-piece using EMM and it has reported that lesser pulse-on time, higher frequency level and usage of mixed electrolyte (sodium nitrate & sodium chloride) yielded good results [4]. The inner walls of cooling channel has also been machined for turbulation purpose through EMM by using electrically conducting gelatinous electrolyte at selected regions in the work-piece [5].Three different electrode materials, namely copper, bronze and tungsten-carbide have been used as tool electrodes to machine nickel-aluminiumbronze alloy to compare their performance. Copper removed maximum amount of material, tungsten-carbide provided good surface quality and less overcut while bronize exhibited moderate performance between these two materials [6]. In the process of EMM study, temperature effect on outcomes has also been studied by applying ultraviolet rays to the electrolyte solution to raise temperature to three different levels. The study has also employed three different optimization methods like GRA (Grey Relational Analysis), VIKOR (VlseKriterijumska Optimizacija I Kompromisno Resenjeto) and TOPSIS (The optimization techniques such as similarity to ideal solution) to compare the results [7]. Attempts have also been made to generate square holes through EMM process on SS-321 specimen using H2SO4 solution [8]. Even magnetic fields have also been used to localize the machining and avoid machining spreading to other adjacent areas [9]. Aluminium7075 composite reinforced with alumina and borosilicate glass powder has been machined under EMM to produce micro-holes on it using NaNO3 and NaCl electrolytes individually. Sodium chloride solution performed lesser due to its aggressive nature. The optimized input combination reported is 10 Volts of voltage , 1.2 Ampere of current and 12 micro-seconds pulse-on time [10]. To reduce the defects in the process of EMM, laser energy assisted hybrid machining has been applied and the process quality
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