Faculty Publications
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Item Multi objective optimisation of thermally enhanced machining parameters of Inconel 718 using grey relational analysis(Inderscience Publishers, 2017) Ganta, V.; Kalichetty, K.S.; Dupadu, D.The present work investigates an experimental study of thermally enhanced machining of nickel-based superalloy Inconel 718 using uncoated tungsten carbide inserts. An inexpensive flame heating technique using an oxyacetylene flame is used as a heat source for thermal enhancement of workpiece. The effects of cutting parameters like cutting speed, feed rate, depth of cut and temperature of workpiece on the performance characteristics like surface roughness, tool wear and material removal rate were studied. A L27 orthogonal array with four parameters and three levels was adopted for experimental design. Multi response optimisation was done using grey relation analysis to simultaneously minimise surface roughness, tool wear and to maximise material removal rate. It was observed that at cutting speed at 85.21 m/min, feed rate at 0.048 m/min, depth of cut at 0.6 mm and workpiece temperature at 600°C were optimal cutting parameters. It is clearly shown that the above performance characteristics in thermally enhanced machining can be improved effectively through this approach. © © 2017 Inderscience Enterprises Ltd.Item Analysis and Optimization of WEDM Performance Characteristics of Inconel 706 for Aerospace Application(Springer Netherlands rbk@louisiana.edu, 2018) Sharma, P.; Dupadu, D.; Narendranath, S.Wire Electrical Discharge Machining (WEDM) has established itself for manufacturing of precise and complex shape components for aerospace application due to the high quality requirement of aerospace components such as normal residual stress, no cracks, no recast layer, no porosity; still there is a need to optimize the control parameter settings and evaluate the performance characteristics of the WEDM process. The experiments have been conducted on Inconel 706 which is a newly-developed superalloy specially for aircraft application. A hybrid approach has been used to optimize the material removal rate (MRR) as well as surface roughness (SR) and significant control parameters have been identified using analysis of variance (ANOVA). Microstructure analysis revealed the formation of microglobules, melted debris and microholes on the machined surface, but no microcrack was detected due to the high toughness of the alloy. Energy dispersive X-ray spectroscopy (EDAX) has been carried out to study the metallurgical changes in the WED machined surface. The topography analysis of the curved surface revealed the best surface quality of the machined component at low pulse on time and high pulse off time. A thick recast layer of 39.6 µm was observed at high pulse on time and low servo voltage. Microhardness of the machined surface was changed up to a depth of 70 µm due to cyclic thermal loading during the WEDM process. © 2017, Springer Science+Business Media Dordrecht.Item Process parameter optimization for FSW of AA6061/SiC/fly ash AMCs using Taguchi technique(ICE Publishing subscriptions@icepublishing.com, 2018) Patil, S.; Narendranath, S.; Dupadu, D.In this research work, aluminum matrix composite (AMC) plates were welded using friction stir welding (FSW). AMCs contain AA6061 as a base metal with silicon carbide (SiC) and fly ash particles as reinforcements. The FSW process parameters considered in this work were tool rotational speed (revolutions/minute), tool traverse speed (millimeters/minute) and tool tilt angle (degrees). The Taguchi L9 orthogonal array was considered for optimizing the process parameters. Tensile strength and hardness were the two output responses obtained by analyzing joint efficiency and signal/noise ratio. An analysis of variance (Anova) study was conducted to identify the percentage contribution of each process parameter to the output responses. The Anova study concluded that among the three process parameters, tool rotational speed was the most dominant parameter in deciding the tensile strength and hardness of the FSW joints, followed by traverse speed and tool tilt angle. At the end, the results were validated by conducting additional experiments. © 2018 ICE Publishing: All rights reserved.Item Experimental evaluation of diamond burnishing for sustainable manufacturing(Institute of Physics Publishing helen.craven@iop.org, 2018) Sachin, B.; Narendranath, S.; Dupadu, D.Diamond burnishing is one of the most popular surface finishing technique used to achieve an excellent surface finish. The aim of the present study is to investigate the effect of process parameters in diamond burnishing of 17-4 PH stainless steel (PH SS) under cryogenic environment. The requirement of a sustainable environment for various machining processes urged to explore the importance of cryogenic burnishing over other cooling techniques. Surface modification was achieved by the application of liquid nitrogen (LN2) during diamond burnishing. The process parameters considered to reduce the surface roughness (Ra) and increase the surface hardness (H) are burnishing speed, burnishing feed and burnishing force. The diamond burnishing experiments were conducted based on the L9 orthogonal array. The significant parameters and the optimal level of each parameters were determined by using analysis of variance (ANOVA) and main effect plots respectively. Multi-response optimization has been carried out for cryogenic diamond burnishing of 17-4 PH stainless steel by using Taguchi's grey relation analysis (TGRA). From the TGRA, it was observed that at burnishing speed 73 m min-1, burnishing feed 0.048 mm/rev and burnishing force 150 N, improved diamond burnishing performance characteristics were obtained. An improvement in grey relation grade (GRG) was found to be 38.47%. Cryogenic diamond burnishing has led to modifications in the microstructure and also an improvement in the subsurface hardness of the material. © 2018 IOP Publishing Ltd.Item Selection of optimal process parameters in sustainable diamond burnishing of 17-4 PH stainless steel(Springer Verlag service@springer.de, 2019) Sachin, B.; Narendranath, S.; Dupadu, D.Secondary finishing operations are the primary requirement of the manufacturing industries to achieve dimensional tolerance of the components. Burnishing is essentially a surface finishing operation usually performed after machining to achieve superfinishing. Diamond burnishing is one of the finest finishing technologies which has been conducted on any surface to attain mirror surface finish. The present work focuses on the development of a correlation model between the process parameters and the output responses while burnishing of 17-4 precipitation hardenable stainless steel using response surface methodology. A novel diamond burnishing tool has been used to analyze the influence of process parameters on output responses in the MQL environment. The control factors considered for the present study include burnishing speed, burnishing feed and burnishing force, and the corresponding output responses considered were surface roughness and surface hardness. The influence of process parameters on output responses has been determined by analysis of variance. Optimization was performed by a multi-objective genetic algorithm. The proposed methodology has been validated by performing experiments at the optimal process parameters, and the achieved results indicate the effectiveness of the diamond burnishing process. © 2019, The Brazilian Society of Mechanical Sciences and Engineering.