Faculty Publications
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Item Studies on the Effect of Process Parameters in Turning of Ti-6Al-4V Alloy Using Topsis(IOP Publishing Ltd, 2019) Rao, C.M.; Rao, S.S.; Herbert, M.A.Optimization of process parameters in turning process is the fundamental machining operation which leads to better machining performance. This study has applied Technique for Order Performance by Similarity to Ideal Solution (TOPSIS) method to obtain the optimum process parameters in turning of Ti-6Al-4V alloy using Polycrystalline Diamond (PCD) cutting tool insert. The process parameters chosen for optimization were cutting velocity, feed rate and depth of cut. The objective is to minimize cutting temperature, tool wear, and surface roughness. TOPSIS is employed to analyze the input parameters on output performance characteristics. Nine experiments were conducted under MQL (Minimum Quantity Lubrication) environment based on an L9 orthogonal array, respectively. The optimization results indicate turning Ti-6Al-4V alloy at cutting velocity of 150 m/min, the feed rate of 0.5 mm/rev and depth of cut of 0.5 mm as optimum parameters obtained by TOPSIS technique. From the Analysis of variance (ANOVA), it was identified that depth of cut parameter is the most influencing process parameter on turning performance characteristics. © Published under licence by IOP Publishing Ltd.Item Optimizing machining responses of homologous TiNiCu shape memory alloys using hybrid ANN-GA approach(Elsevier Ltd, 2022) Roy, A.; Sachin, B.; Raghavendra, T.; Rao, C.M.; Naik, G.M.; Soni, H.; Mashinini, P.M.; Narendranath, S.Fabrication of shape memory alloys using wire electro discharge machining (WEDM) has gained popularity over the last few years. Most widely used machining parameters of WEDM process are pulse on time (Øon), pulse off time (Øoff), servo voltage (σ) and wire feed (ω). WEDM responses like material removal rate (MR), surface roughness (SR), kerf width (KW) and recast layer thickness (LT) have been evaluated by researchers to determine machining characteristics and are also considered for this study. These machining responses determine the quality of machining and are majorly influenced by thermal conductivity and melting temperature of the WEDM workpiece. Actuation behavior of shape memory alloys is a function of phase transformation characteristics which in turn depends on elemental composition of the selected alloys. Therefore, dissimilar machining responses of Ti50Ni40Cu10 and Ti50Ni25Cu25 have been observed even though similar machining input values were used. This study utilized artificial neural network (ANN) mapping to establish WEDM response function – which was used as fitness function to perform multi objective optimization using genetic algorithm (GA). It was found that ANN successfully predicted machining responses of selected homologous alloys and GA helped in identifying suitable input parameter values to optimize machining responses. © 2022Item Development of novel cutting tool with a micro-hole pattern on PCD insert in machining of titanium alloy(Elsevier Ltd, 2018) Rao, C.M.; Rao, S.S.; Herbert, M.A.The development of a novel cutting tool that had a micro-hole pattern on their rake and flank face of cutting tool surface has found wider potential in the field of manufacturing. Micro-hole pattern features on a tool rake face help in controlling the tribological characteristics of the cutting tool. Micro-holes with the different number of holes orientation, diameter and depth were fabricated using the advanced application of the electrical discharge super drilling machine with the view to assist lubricant penetration and retention. A comparative study has been conducted between micro-hole patterned Polycrystalline Diamond (PCD) cutting insert and the commercially available PCD cutting insert. The effect of micro-hole pattern on the machining of Titanium alloy (Ti-6Al-4 V) is investigated with the application of the Minimum Quantity Lubrication (MQL) method in turning operation. Vibration signals were captured in feed force direction and measured using the tri-axial accelerometer. The cutting temperature, tool-wear, and chip-morphology were measured with an infrared thermometer and Scanning Electron Microscope (SEM). It was found that micro-hole textured inserts reduced the friction on the rake face resulting in the decrease of vibration up to 30–50%. The cutting temperature, tool wear and surface roughness were reduced to 30%, 50% and 40%, respectively. The conical and helical chips were produced in micro pool lubrication system. The friction coefficient can be minimized at the tool-chip interface by using liquid lubrication method. There is no unfavourable effect on the performance of cutting tools having holes on the cutting tool surface. All these parameters led to the improvement in the tool life. © 2018Item An Experimental and Numerical Approach to Study the Performance of Modified Perforated Cutting Tools on Machining of Ti–6Al–4V Alloy(Springer, 2020) Rao, C.M.; Rao, S.S.; Herbert, M.A.In this research, the main aim is to reduce the unfavorable effects that occurred during machining of the Ti–6Al–4V alloy by perforating the rake face and the flank face of the cutting insert. The main novelty in this research is that machining of Ti–6Al–4V alloy with the micro-hole textured insert helps in the improvement of tribological properties and also reduces cutting temperature at chip–tool interface with proper lubricating effect. To validate the micro-hole textured tools, it is compared with conventionally available insert. The deformation of Ti–6Al–4V alloy with modified cutting inserts was simulated, considering tool as rigid body and workpiece as elasto-plastic material. DEFORM 3D software was used for the simulation of the machining process with the updated Lagrangian formulation. To predict the cutting temperature and chip morphology, the thermo-mechanical analysis was applied using Johnson–Cook material model for the machining process. The turning of the Ti–6Al–4V alloy was carried out with the modified polycrystalline diamond (PCD) cutting inserts (Design 1 and Design 2) and commercially available PCD insert (normal insert). Coconut oil was used as a micro-pool lubricant during the machining process under minimum quantity lubrication environment. In the present work, the turning performance characteristics such as cutting temperature, cutting vibration, tool wear, chip morphology and surface integrity were measured during machining of the Ti–6Al–4V alloy. The experimental results of cutting temperature and chip morphology were validated with the simulation results with better accuracy. The machining results of Design 2 cutting insert showed maximum reduction of 30%, 38%, 45% and 35% in cutting temperature, cutting vibration, tool wear and surface roughness, respectively, when compared with machining under normal insert and Design 1 cutting insert. It is also evident from the results that machining with Design 2 cutting insert significantly improved the process performance of the product quality at higher feed rates. © 2019, King Fahd University of Petroleum & Minerals.Item Minimum Quantity Lubrication through the micro-hole textured PCD and PCBN inserts in the machining of the Ti–6Al–4V alloy(Elsevier Ltd, 2021) Rao, C.M.; Sachin, B.; Rao, S.S.; Herbert, M.A.A novel cutting tool development with the micro-hole textures on the flank and rake face of the cutting inserts helps in the reduction of tribological properties. The machining of Ti–6Al–4V alloy leads to some challenges during machining namely higher cutting temperature, and rapid tool wear. In this research, a comparison study has been performed with the new cutting tool inserts with surface modification such as Polycrystalline Cubic Boron Nitride (PCBN) and Polycrystalline Diamond (PCD) inserts for high-speed machining of Ti–6Al–4V alloy. The influence of the micro-hole textured insert on the machining of the Ti–6Al–4V alloy was investigated with the Minimum Quantity Lubrication (MQL) method. Compared to modified PCBN inserts, modified PCD inserts showed better results in all the performance characteristics. © 2020 Elsevier LtdItem Influence of slide burnishing process on the surface characteristics of precipitation hardenable steel(Springer Nature, 2021) Sachin, B.; Rao, C.M.; Naik, G.M.; Puneet, N.P.The surface integrity of the material is the predominant necessity of a component to perform efficiently in varying working conditions. To improve the surface integrity of the workpiece secondary finishing processes are being performed. This work attempts to propose a realistic cryogenic slide burnishing condition for improvement of the surface integrity. The slide burnishing was performed by a novel slide burnishing tool on 17–4 precipitation hardenable stainless steel. The experiment was designed based on a central composite design. Initially, the effect of control parameters on the output response was examined by experimental analysis based on the design of experiment. Analysis of variance was used to analyze the influence of the variables on the performance indices. The regression technique was used to develop an empirical model. Optimization of process parameters for finding minimum surface roughness and maximum surface hardness was achieved by a multi-objective genetic algorithm. The optimized solutions were validated by performing confirmation experiments. © 2021, The Author(s).