Faculty Publications
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Item A review on machining of titanium based alloys using EDM and WEDM(Institute of Problems of Mechanical Engineering mpm@def.ipme.ru, 2014) Manjaiah, M.; Narendranath, S.; Basavarajappa, S.The aim of this review is to present the consolidated information about the contributions of various researchers on the application of EDM and WEDM on titanium materials and subsequently identify the research gaps. The literature survey has been carried out from three perspectives such as application of EDM and WEDM on titanium materials, utilization of tools and techniques for correlating experimental results and application of products produced by EDM and WEDM. Three main research areas has been identified. First, the application of EDM and WEDM on titanium materials mainly TiNi based alloys. Second, the utilization of advanced tools and techniques such as artificial neural network (ANN), advanced particle swarm optimization (PSO) and tabu enhanced genetic algorithm (GA). Third, the study and analysis of surface integrity in EDM and WEDM on titanium materials. In addition, the paper has also evolved the future research directions. The paper has been concluded by indicating the future research directions for the research gaps identified during this literature survey.Item Wire electric discharge machining characteristics of titanium nickel shape memory alloy(Nonferrous Metals Society of China B12 Fuxing Road Beijing 100814, 2014) Manjaiah, M.; Narendranath, S.; Basavarajappa, S.; Gaitonde, V.N.TiNi shape memory alloys (SMAs) have been normally used as the competent elements in large part of the industries due to outstanding properties, such as super elasticity and shape memory effects. However, traditional machining of SMAs is quite complex due to these properties. Hence, the wire electric discharge machining (WEDM) characteristics of TiNi SMA was studied. The experiments were planned as per L27 orthogonal array to minimize the experiments, each experiment was performed under different conditions of pulse duration, pulse off time, servo voltage, flushing pressure and wire speed. A multi-response optimization method using Taguchi design with utility concept has been proposed for simultaneous optimization. The analysis of means (ANOM) and analysis of variance (ANOVA) on signal to noise (S/N) ratio were performed for determining the optimal parameter levels. Taguchi analysis reveals that a combination of 1 ?s pulse duration, 3.8 ?s pulse off time, 40 V servo voltage, 1.8×105 Pa flushing pressure and 8 m/min wire speed is beneficial for simultaneously maximizing the material removal rate (MRR) and minimizing the surface roughness. The optimization results of WEDM of TiNi SMA also indicate that pulse duration significantly affects the material removal rate and surface roughness. The discharged craters, micro cracks and recast layer were observed on the machined surface at large pulse duration.Item Effect of combined grain refinement and modification on microstructure and mechanical properties of hypoeutectic, eutectic and hypereutectic Al-Si alloys(Inderscience Publishers, 2015) Shivaprasad, C.G.; Kiran Aithal, K.; Narendranath, S.; Desai, V.; Mukunda, P.G.The effect of melt treatment owing to the combined addition of grain refiner and modifier on the microstructure and mechanical properties of Al-Si alloys having 7% (hypoeutectic), 12% (eutectic) and 15% silicon (hypereutectic) is studied. 1 wt. % of Al-1Ti-3B Master alloy was used as grain refiner. For modification of eutectic Si, 0.2 wt. % of Al-10Sr Master alloy was added to hypoeutectic alloy and 0.4 wt. % is added to eutectic alloy as well as hypereutectic alloy. Furthermore, refinement of primary Si in hypereutectic alloy was achieved by addition of 0.04 wt. % of phosphorus. The goal of this investigation is to determine the influence of combined addition of grain refiner and modifier on mechanical properties and qualitatively correlate with the microstructural changes. © 2015 Inderscience Enterprises Ltd.Item Effect of electrode material in wire electro discharge machining characteristics of Ti50Ni50-xCux shape memory alloy(Elsevier Inc. usjcs@elsevier.com, 2015) Manjaiah, M.; Narendranath, S.; Basavarajappa, S.; Gaitonde, V.N.Abstract TiNiCu alloy belongs to new class of shape memory alloy (SMA), which exhibits superior properties like shape memory effect, super elasticity and reversible martensitic transformation phase and thus find broad applications in actuators, micro tools and stents in biomedical components. Even though, SMA demonstrates outstanding property profile, traditional machining of SMAs is fairly complex and hence non-traditional machining like wire electric discharge machining (WEDM) has been performed. Hence, there is a need to investigate the WEDM performance characteristics of shape memory alloys due to excellent property profile and potential applications. In the present investigation, various machining characteristics like material removal rate (MRR), surface roughness, surface topography and metallographic changes have been studied and the influence of wire material on TiNiCu alloy machining characteristics has also been evaluated through ANOVA. Ti50Ni50-xCux=10, 20 was prepared by vacuum arc melting process. The proposed alloy as-cast material exhibits austenite property (B2 phase) and having higher hardness when compared to TiNi alloy. The investigation on WEDM of Ti50Ni50-xCux alloy reveals that the machining parameters such as servo voltage, pulse on time and pulse off time are the most significant parameters affecting MRR as well as surface roughness using both brass and zinc coated brass wires. However, machining with zinc coated brass wire yields reduced surface roughness and better MRR and also produces less surface defects on the machined surface of Ti50Ni50-xCux alloys. © 2015 Elsevier Inc. All rights reserved.Item Influence of process parameters on material removal rate and surface roughness in WED-machining of Ti50Ni40Cu10 shape memory alloy(Inderscience Publishers, 2016) Manjaiah, M.; Narendranath, S.; Basavarajappa, S.; Gaitonde, V.N.Among the shape memory alloys (SMAs), TiNi SMAs have been typically used as the functional elements in the larger part of the industries due to exceptional properties like super elasticity and shape memory effect. However, traditional machining of these alloys is fairly complex due to these properties. The non-traditional machining process like electric discharge machining (EDM) exhibits outstanding capability in machining of these alloys. The poor selection of machining parameters may cause increased roughness of workpiece and lesser material removal rate. Hence, an effort has been made in the present work to explore the effects of three process parameters, such as pulse on time, pulse off time and servo voltage in wire electric discharge machining (WEDM) of Ti50Ni40Cu10 shape memory alloy (SMA) using zinc coated brass wire electrode on material removal rate and surface roughness using response surface methodology (RSM)-based mathematical models. The experiments were planned as per central composite design (CCD). The investigations revealed that pulse on time and servo voltage have predominant effects in maximising material removal rate and minimising surface roughness. The best combination of the process parameters for multi-response optimisation was obtained through desirability function. ©2016 Inderscience Enterprises Ltd.Item ANN and RSM modeling methods for predicting material removal rate and surface roughness during WEDM of Ti50Ni40Co10 shape memory alloy(AMSE Press 16 Avenue Grauge Blanche Tassin-la-Demi-Lune 69160, 2017) Soni, H.; Narendranath, S.; Ramesh, M.R.Present study exhibits the comparison between experimental and predicted values. Where response surface method (RSM) and artificial neural network (ANN) were used as predictor for the prediction of wire electro discharge machining (WEDM) responses such as the material removal rate (MRR) and surface roughness (SR) during the machining of Ti50Ni40Co10 shape memory alloy. It has been noticed from the literature survey that pulse on time and servo voltage are most important process parameters for the machining of TiNiCo shape memory alloy, hence there are five levels of these process parameters were chosen for the present study. For the present study selected alloy has been developed through vacuum arc melting and L-25 orthogonal array has been created by using Taguchi design of experiment (DOE) for experimental plan. During the present study ANN predicted values have been found to very close to experimental values compare to RSM predicted values, hence it can be say that ANN predictor gives more accurate values compare to RSM predicted values. © 2017 AMSE Press. All rights reserved.Item Investigation on material removal rate, surface and subsurface characteristics in wire electro discharge machining of Ti50Ni50-xCux shape memory alloy(SAGE Publications Ltd info@sagepub.co.uk, 2018) Manjaiah, M.; Narendranath, S.; Basavarajappa, S.; Gaitonde, V.TiNiCu shape memory alloys have superior properties as compared with NITINOL due to their greater ductility, reduced hysteresis temperature range, and quick actuation response. The present article investigates the surface and subsurface modifications occurring due to wire electro discharge machining of Ti50Ni50-xCux shape memory alloy. The machining experiments were performed considering the pulse on time, pulse off time, and servo voltage as the process parameters. The influence of these parameters was studied on the material removal rate, surface roughness, recast layer thickness, microhardness, and phase changes in the machined surface. Longer pulse on time causes greater discharge energy, hence leading to higher material removal rate, surface roughness, and recast layer thickness. The machined surface hardness increased up to 900 Hv, which is about 59% increase with respect to the base material for longer pulse on time due to the recast layer thickness and the formation of oxides. A phase change on the machined surface was observed to cause the shape recoverability of the alloy. The microstructure, composition through EDAX, and the phase changes of the machined surface are also discussed in the article. © 2015, © IMechE 2015.Item Experimental Investigation on Effects of Wire Electro Discharge Machining of Ti50Ni45Co5 Shape Memory Alloys(Springer Netherlands rbk@louisiana.edu, 2018) Soni, H.; Narendranath, S.; Ramesh, M.R.TiNiCo shape memory alloy is most popular shape memory alloy for biomedical applications due to their outstanding properties such as shape memory effect, pseudoelasticity and transformation temperature. Machining of such kind of alloys is very difficult through conventional machining process is very difficult because they may affect their internal properties of these alloys. However conventional machining processes give poor surface quality during the machining hence non-conventional machining processes such as (wire electro discharge machining, water jet machining and electro discharge machining etc.) are more suitable for machining of such kind of alloy. From the literature it has been found that Wire electro discharge machining (WEDM) is more suitable non-conventional machining process for such kind of alloy. Present study exhibits the effects WEDM characteristics of Ti50Ni45Co5 shape memory alloy. L-9 orthogonal array has been created by using Taguchi as a design method for machining of selected alloy and machined surface characterization has been carried out at the optimized process parameters with respect to microstructures, surface topography, microhardness, XRD analysis and residual stresses. To find the optimum setting of the input process parameters a couple of optimization techniques are used, namely principal component analysis (PCA) and Gray relational analysis (GRA) technique. 125?s pulse on time (Ton), 35?s pulse off time (Toff) and 40V servo voltage (SV) were found as an optimal setting for the higher material removal rate (MRR) with better surface roughness (SR) in the present study. Moreover, characterization of the machined surface is performed with respect to microstructures, surface topography, microhardness analysis, XRD and residual stresses. Harder surface observed near the cutting edge and TiNio3 Tio2 and CuZn were noticed on the surface of machined component through XRD analysis. However, compressive residual stress has been noticed on the machined surface during WEDM process. © 2018, Springer Science+Business Media B.V., part of Springer Nature.Item Impact of variation in wire electro discharge machining responses of homologous TiNiCu shape memory alloys for smart applications: An experimental investigation(Institute of Physics Publishing helen.craven@iop.org, 2018) Roy, A.; Narendranath, S.In this study, three distinct TiNiCu alloys were processed using wire electro discharge machining. These alloys are potential materials for smart applications owing to their fast actuation response resulting from suitable martensitic transformation temperatures. Due to differences in their physical property (thermal conductivity in this case), these alloys exhibit variation in machining response during wire electro discharge machining. Based on wire electro discharge machining responses of these alloys, order of thermal conductivity of these alloys are concluded in this study. This investigation aims at addressing the variation in terms of kerf width, recast layer thickness and machined surface microhardness to form the basis for production of intricate components. Ti50Ni40Cu10 alloy exhibited diverging machining response compared to its counterparts. Influential parameter for a given machining response changes depending on thermal property of the workpiece which makes it vital to investigate and choose the parameters in a more sensible manner while machining such materials. It was found that kerf width decreases with increasing servo voltage whereas recast layer thickness (mostly influenced by pulse off duration) increases with increasing pulse off duration. Microhardness of the machined surface (mostly influenced by pulse on duration) increases at higher discharge energy levels owing to presence of oxides formed during spark erosion process. Microhardness of Ti40Ni50Cu10 was found to be high (approximately 560 Hv) compared to its counterparts which was due to presence of Ni rich and ?-CuTi precipitates which also affected its phase transformation temperatures. © 2018 IOP Publishing Ltd.Item Effects of Wire Electro-Discharge Machining Process Parameters on the Machined Surface of Ti 50 Ni 49 Co 1 Shape Memory Alloy(Springer Netherlands rbk@louisiana.edu, 2019) Soni, H.; Narendranath, S.; Ramesh, M.R.Wire electro-discharge machining is one of the advanced machining processes which can machine all conductive materials without changing their internal properties. Pulse on time and servo voltage are the most influential process parameters of wire electro-discharge machining. In the present study, attempts have been made to study the effects of these process parameters on the machined surface of Ti 50 Ni 49 Co 1 shape memory alloy by adopting a two process parameters experimental design approach. Cutting speed and surface roughness were considered as output parameters; surface crack density, microhardness and XRD analysis were carried out at the higher and lower values of these parameters. Higher surface crack density has been found at high values of cutting speed (125 ?s pulse on time and 20 V servo voltage) while it is lower at the lower value of cutting speed (105 ?s pulse on time and 60 V servo voltage). Moreover, a harder surface was found near the machined surface. By XRD analysis it was found that the crystal size of the WED machined surface was reduced at high T on and lower SV. © 2018, Springer Science+Business Media B.V., part of Springer Nature.