IJE TRANSACTIONS C: Aspects Vol. 27, No. 3 (March 2014) 417-424   

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M. Azadi Moghaddam and F. Kolahan
( Received: March 24, 2013 – Accepted: September 14, 2013 )

Abstract    Nowadays, Electrical Discharge Machining (EDM) has become one of the most extensively used non-traditional material removal process. Its unique feature of using thermal energy to machine hard to machine electrically conductive materials is its distinctive advantage in the manufacturing of moulds, dies and aerospace components. Howevere, EDM is a costly process and hence proper selection of its process parameters is essential to reduce production cost and improve product quality. In this study the effect of input EDM parameters on 2312 hot worked steel, widely used in mold manufacturing, is modeled and optimized. The proposed approach is based on statistical analysis on the experimental data. The input parameters are peak current (I), pulse on time (Ton), pulse off time (Toff), duty factor (h) and voltage (V). Surface roughness is the most important performance characteristic in EDM. The experimental data are gathered using Taguchi L36 design matrix. In order to establish the relations between input and output parameters, various regression functions have been fitted on the experimental data. In the last section of this research, genetic algorithm has been employed for optimization of process parameters. Using the proposed optimization procedure, proper levels of input parameters for any desirable output can be identified. A verification test is also performed to verify the accuracy of optimization procedure in determining the optimal levels of machining parameters. The results indicate that the proposed modeling technique and genetic algorithm are quite efficient in modeling and optimization of EDM process parameters.


Keywords    Taguchi technique, Signal to noise analysis (S/N), Electrical discharge machining (EDM), Optimization, genetic algorithm (GA), Analysis of variance (ANOVA).


چکیده    امروزه ماشين‌كاري تخليه الكتريكي به يكي از پركاربردترين فرآيندهاي پيشرفته ماشين‌كاري تبديل شده است. در اين فرآيند به دليل استفاده از انرژي گرمايي براي براده‌برداري، سختي ماده‌، عامل باز دارنده نبوده و مي‌توان مواد سختي كه براي ساخت قالب‌هاي تزريق پلاستيك و قطعات مربوط به صنعت هوا و فضا به کار می­روند را به آساني ماشين‌كاري كرد. از آنجا كه اين فرآيند هزينه‌بر مي‌باشد لذا انتخاب صحيح پارامترهاي ماشين‌كاري در قيمت تمام شده‌ و كيفيت قطعات توليدي مؤثر مي‌باشد. در اين تحقيق تاثير پارامترهای تنظيمی در ماشين‌كاري تخليه الکتريکی فولاد گرم‌كار 2312 مورد استفاده در صنعت قالب‌سازي، مدل­سازی و بهينه­سازی شده است. مدل­سازی فرآيند توسط روش­های آماری و با استناد بر داده­های تجربی انجام يافته است. پارامترهاي ورودي شامل جريان الكتريسيته، ‌زمان‌هاي روشني و خاموشي پالس، فاكتور كار و ولتاژكاري مي‌باشند. همچنين زبري سطح به عنوان مشخصه خروجي فرآيند درنظر گرفته شده ­است. به منظور گردآوری داده­های مورد نياز در انجام اين تحقيق، آزمايشات تجربی با استفاده از طرح تاگوچي L36 انجام شده است. پس از اخذ داده­های مورد نظر، جهت ايجاد ارتباط بين پارامترهاي ورودي و مشخصه‌ خروجي با بکارگيری تابع رگرسيونی، مدل‌ رياضي طراحی گرديده است. در بخش آخر اين تحقيق، با به کار گيري الگوريتم ژنتيك، تابع بهينه­سازی براي زبري سطح به کار گرفته شد. نتايج بهينه­سازی نيز توسط آزمايشات تجربی صحه­گذاری مجدد گرديد. نتايج حاصل از بهينه‌سازي و آزمايشات تجربي نشان داد كه به كارگيري هم‌زمان روش تاگوچي و الگوريتم ژنتيك مي‌تواند به ابزاري كارامد جهت بهينه‌سازي فرآيند تخليه الكتريكي تبديل شود.


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