Electrical discharge machining is one of the earliest nontraditional machining, extensively used in industry for processing of parts having unusual profiles with reasonable precision. In the present work, an attempt has been made to model material removal rate, electrode wear rate, and surface roughness through response surface methodology in a die sinking EDM process. The optimization was performed in two steps using one factor at a time for preliminary evaluation and a Box-Behnken design involving three variables with three levels for determination of the critical experimental conditions. Pulse on time, pulse off time, and peak current were changed during the tests, while a copper electrode having tubular cross section was employed to machine through holes on EN 353 steel alloy workpiece. The results of analysis of variance indicated that the proposed mathematical models obtained can adequately describe the performances within the limits of factors being studied. The experimental and predicted values were in a good agreement. Surface topography is revealed with the help of scanning electron microscope micrographs. 1. Introduction Electrodischarge machining is a nonconventional machining process extensively used in industry for processing of parts having unusual profiles with reasonable precision [1]. Steel is a widely used engineering material. There are a variety of steels used for numerous applications. The steel is being divided into low carbon, medium carbon, and high carbon steel on the basis of carbon content. Low carbon steel contains a carbon content from 0.15% to 0.45%. It is the most common form of steel as it provides material properties that are acceptable for many applications [2]. EN 353 steel is cheaply available and widely used alloy. EN 353 is low alloy case carburized steel, predominantly used for manufacturing heavy-duty gears, shafts, pinions, and especially crown wheel [3]. Discharge current was the most significant controlling parameter in machining Al-15% SiC MMC using multihole electrode by grey relational analysis, while Taguchi method was employed to determine the relations between the machining parameters and process characteristics like MRR (material removal rate), EWR (electrode wear rate), and SR (surface roughness) [4]. The combination of maximum pulse on time and minimum pulse off time gives maximum MRR on Al-7075 alloy with brass electrode using Taguchi approach [5]. Amorim and Weingaertner concluded that the best results of MRR and surface texture for duty factor of 0.5 were obtained with tungsten-copper electrodes,
References
[1]
S. Rajesha, A. K. Sharma, and P. Kumar, “On electro discharge machining of inconel 718 with hollow tool,” Journal of Materials Engineering and Performance, vol. 21, no. 6, pp. 882–891, 2012.
[2]
S. R. Nimbhorkar and B. D. Deshmukh, “Effect of case hardening treatment on the structure and properties of automobile gears,” International Journal of Pure and Applied Research in Engineering and Technology, vol. 1, no. 8, pp. 317–325, 2013.
[3]
A. Bensely, S. Venkatesh, D. Mohan Lal, G. Nagarajan, A. Rajadurai, and J. Boland, “Determination of poisson's ratio of cryogenically treated case carburized steel (En 353) by using ultrasonic technique,” in Proceedings of the International Conference on Manufacturing Science and Technology, pp. 361–365, 2006.
[4]
S. Murugesan and K. Balamurugan, “Optimization by Grey relational analysis of EDM parameters in machining Al-15% SiC MMC using multihole electrode,” Journal of Applied Sciences, vol. 12, no. 10, pp. 963–970, 2012.
[5]
S. Singh and M. Verma, “A parametric optimization of electric discharge drill machine using taguchi approach,” Journal of Engineering, Computers & Applied Sciences, vol. 1, no. 3, pp. 39–48, 2012.
[6]
F. L. Amorim and W. L. Weingaertner, “Die-sinking electrical discharge machining of a high-strength copper-based alloy for injection molds,” Journal of the Brazilian Society of Mechanical Sciences and Engineering, vol. 26, no. 2, pp. 137–144, 2004.
[7]
O. Yilmaz, A. T. Bozdana, M. A. Okka, and I. H. Filiz, “A comparative investigation of the effects of single and multi-channel electrodes in EDM fast hole drilling of aerospace alloys,” in Proceedings of the 5th International Conference and Exhibition on Design and Production of Machines and Dies/Molds, Kusadasi, Turkey, June 2009.
[8]
R. Manikandan and R. Venkatesan, “Optimizing the machining parameters of micro-EDM for Inconel 718,” Journal of Applied Sciences, vol. 12, no. 10, pp. 971–977, 2012.
[9]
N. Sharma, R. Khanna, and R. D. Gupta, “Parametric optimization on WEDM for HSLA by integrated RSM and genetic algorithm,” in AEMDS, 2014.
[10]
G. Kibria, B. R. Sarkar, B. B. Pradhan, and B. Bhattacharyya, “Comparative study of different dielectrics for micro-EDM performance during microhole machining of Ti-6Al-4V alloy,” International Journal of Advanced Manufacturing Technology, vol. 48, no. 5-8, pp. 557–570, 2010.
[11]
M. S. Azad and A. B. Puri, “Simultaneous optimisation of multiple performance characteristics in micro-EDM drilling of titanium alloy,” International Journal of Advanced Manufacturing Technology, vol. 61, no. 9-12, pp. 1231–1239, 2012.
[12]
A. D. Patel, M. C. Parekh, B. B. Patel, and B. B. Patel, “Multi-objective optimisation of die sinking electro discharge machining process using Taguchi,” International Journal of Engineering Research and Applications, vol. 2, no. 6, pp. 1367–1371, 2012.
[13]
P. Janmanee and A. Muttamara, “Optimization of electrical discharge machining of composite 90WC-10Co base on taguchi approach,” European Journal of Scientific Research, vol. 64, no. 3, pp. 426–436, 2011.
[14]
M. Boujelbene, E. Bayraktar, W. Tebni, and S. Ben Salem, “Influence of machining parameters on the surface integrity in electrical discharge machining,” International Scientific Journal, vol. 37, no. 2, 2009.
[15]
A. K. Khanra, S. Patra, and M. M. Godkhindi, “Electrical discharge machining studies on reactive sintered FeAl,” Bulletin of Materials Science, vol. 29, no. 3, pp. 277–280, 2006.
[16]
H. K. Kansal, S. Singh, and P. Kumar, “Parametric optimization of powder mixed electrical discharge machining by response surface methodology,” Journal of Materials Processing Technology, vol. 169, no. 3, pp. 427–436, 2005.
[17]
T. Y. Tai and S. J. Lu, “Improving the fatigue life of electro-discharge-machined SDK11 tool steel via the suppression of surface cracks,” International Journal of Fatigue, vol. 31, no. 3, pp. 433–438, 2009.
[18]
A. Kumar, V. Kumar, and J. Kumar, “Investigation of machining parameters and surface integrity in wire electric discharge machining of pure titanium,” Proceedings of the Institution of Mechanical Engineers B: Journal of Engineering Manufacture, vol. 227, no. 7, pp. 972–992, 2013.
[19]
A. T. Bozdana, O. Yilmaz, M. A. Okka, and ?. H. Filiz, “A comparative experimental study on fast hole EDM of Inconel 718 and Ti-6Al-4V,” in Proceedings of the 5th International Conference and Exhibition on Design and Production of MACHINES and DIES/MOLDS, 2009.
[20]
U. ?ayda? and A. Has?alik, “Modeling and analysis of electrode wear and white layer thickness in die-sinking EDM process through response surface methodology,” International Journal of Advanced Manufacturing Technology, vol. 38, no. 11-12, pp. 1148–1156, 2008.
[21]
N. Sharma, R. Khanna, and R. Gupta, “Multi quality characteristics of WEDM process parameters with RSM,” Procedia Engineering, vol. 64, pp. 710–719, 2013.
[22]
N. Sharma, R. Khanna, R. D. Gupta, and R. Sharma, “Modeling and multiresponse optimization on WEDM for HSLA by RSM,” International Journal of Advanced Manufacturing Technology, vol. 67, no. 9-12, pp. 2269–2281, 2013.
[23]
P. Gupta, R. Khanna, R. D. Gupta, and N. Sharma, “Effect of process parameters on kerf width in WEDM for HSLA using response surface methodology,” Journal of Engineering Technology, vol. 2, no. 1, pp. 1–5, 2012.
[24]
A. Kumar, V. Kumar, and J. Kumar, “Multi-response optimization of process parameters based on response surface methodology for pure titanium using WEDM process,” International Journal of Advanced Manufacturing Technology, vol. 68, no. 9–12, pp. 2645–2668, 2013.
[25]
D. C. Whittinghill, “A note on the robustness of Box-BEHnken designs to the unavailability of data,” Metrika, vol. 48, no. 1, pp. 49–52, 1998.
[26]
K. Ojha, R. K. Garg, and K. K. Singh, “MRR improvement in sinking electrical discharge machining: a review,” Journal of Minerals & Materials Characterization & Engineering, vol. 9, no. 8, pp. 709–739, 2010.
[27]
N. Kumar, L. Kumar, H. Tewatia, and R. Yadav, “Comparative study for MRR on die-sinking EDM using electrode of copper & graphite,” International Journal of Advanced Technology & Engineering Research, vol. 2, no. 2, pp. 170–174, 2012.
[28]
A. Kumar, V. Kumar, and J. Kumar, “Investigation of microstructure and element migration for rough cut surface of pure titanium after WEDM,” International Journal of Microstructure and Materials Properties, vol. 8, no. 4-5, pp. 343–356, 2013.