Conference Papers
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Item A pressured steam JET approach to tool wear minimization in cutting of metal matrix composites(Trans Tech Publications Ltd, 2007) Anjaiah, D.; Shetty, R.; Pai B, R.; Vijaya, M.V.; Rao, S.S.Metal matrix composites (MMCs) have been found to possess tremendous prospective engineering applications that require materials offering a combination of lightweight with considerably enhanced mechanical and physical properties. However, the applications of MMCs are limited by their poor machinability which is a result of their highly abrasive nature that causes excessive wear to the cutting tools. In this study, an investigation into the mechanism of the tool wear in cutting of MMCs is carried out. It is found that during cutting of an MMC, the tool cutting edge will impact on the reinforcement particles. The impacted particles will then either be dislodged from the matrix, doing no harm to the tool, or be embedded into the matrix, ploughing on the tool flank and causing excessive tool flank wear. According to this tool wear mechanism, a pressured steam jet approach is developed for the minimization of the tool wear by preventing the impacted reinforcement particles from being embedded in the workpiece matrix. Experimental tests for cutting of SiC-aluminum MMC using cubic boron nitride (KB-90) and polycrystalline diamond (KP-300) tool inserts with the aid of the pressured steam jet are conducted. The results show that from full factorial design of experiments the effect of the pressured steam jet plays a significant role on the tool wear followed by tool inserts and depth of cut. The working mechanism of the pressured steam jet method and the experimental testing results are discussed in detail.Item Inference of optimal speed for sound centrifugal casting of Al-12Si alloys(2011) Rao, S.; Mukunda, P.G.; Rao, S.S.; Sudhakar, K.G.True centrifugal casting is a standard casting technique for the manufacture of hollow, intricate and sound castings without the use of cores. The molten metal or alloy poured into the rotating mold forms a hollow casting as the centrifugal forces lift the liquid along the mold inner surface. When a mold is rotated at low and very high speeds defects are found in the final castings. Obtaining the critical speed for sound castings should not be a matter of guess or based on experience. The defects in the casting are mainly due to the behavior of the molten metal during the teeming and solidification process. Motion of molten metal at various speeds and its effect during casting are addressed in this paper. Eutectic Al-12Si alloy is taken as an experiment fluid and its performance during various rotational speeds is discussed.Item Prediction of surface finish and optimization of machining parameters in turning(2012) Prasad, D.; Krishna, P.; Rao, S.S.Surface roughness plays a crucial role in the functional capacity of machined parts. In this work, experiments were carried out on a conventional lathe for different cutting parameters namely feed, spindle speed, depth of cut and tool nose radius according to Taguchi Design of Experiments. Radial acceleration readings were taken with an accelerometer. Optimum cutting parameters and their level of significance were found using Taguchi analysis (ANOVA). Regression analysis was carried out to identify whether the experimental roughness values have fitness characteristic with the process parameters. Recurrence Plots (RP) were obtained using the sensor signals which determine surface roughness qualitatively and Recurrence Quantification Analysis (RQA) technique was used to quantify the RP obtained. Surface finish was predicted using a feed forward back propagation neural network with RQA parameters, cutting parameters and acceleration data as inputs to the network. The validity and reliability of the methods were verified experimentally. © (2012) Trans Tech Publications.Item Future applications of carbon nanotube reinforced functionally graded composite materials(2012) Udupa, G.; Rao, S.S.; Gangadharan, K.V.Future applications demand materials having extraordinary mechanical, thermal and chemical properties which must sustain the different environment conditions and in the same time available easily at reasonable prices. The carbon nanotubes(CNT) reinforced functionally graded composite materials(FGCM) is expected to be the new generation material having a wide range of unexplored potential applications in various technological areas such as aerospace, defence, energy, automobile, medicine, structural and chemical industry. They can be used as gas adsorbents, templates, actuators, catalyst supports, probes, chemical sensors, nanopipes, nano-reactors etc. This paper explores in detail the different possibilities of application of CNT reinforced functionally graded composites and manufacturing techniques, which raise the awareness on the promise of nanotechnology and the potential impact on aerospace industry as well as on other areas. © 2012 Pillay Engineering College.Item Investigation on microstructure and mechanical properties of Friction Stir Welded AA6061-4.5Cu-10SiC composite(Institute of Physics Publishing michael.roberts@iop.org, 2016) Herbert, M.; Shettigar, A.K.; Nigalye, A.V.; Rao, S.S.The application of Metal Matrix Composites (MMCs) is restricted by the availability of properly developed fabrication methods. The main challenge here is the fabrication and welding of MMCs in a cost effective way. In the present study, synthesis of AA6061-4.5%Cu- 10%SiC composite was done by stir casting method. The joining of MMCs was performed by Friction Stir Welding (FSW) using a combination of square and threaded profile pin tool (CSTPP). Further, the welded composite was evaluated for microstructure and joint properties. The microstructural characterization showed uniform distribution of refined fine grains and numerous small particles at nugget zone. The hardness at the stir zone is higher than that of the base material. The tensile test revealed 96% joint efficiency in transverse direction. © Published under licence by IOP Publishing Ltd.Item Influence of welding process parameters on microstructure and mechanical properties of friction stir welded aluminium matrix composite(Trans Tech Publications Ltd ttp@transtec.ch, 2017) Prabhu B, S.; Shettigar, A.K.; Karthik, K.; Rao, S.S.; Herbert, M.In this study, the effect of process parameters on microstructure and mechanical properties of friction stir welded aluminium matrix composites(AMC) have been explored. The results indicated that the recrystallized grain size at the bottom of the weld region is smaller than that at the top region due to difference in the heat transfer at the weld region. The joint strength of AMCs depends on proper selection of process parameters like tool rotational speed and welding speed. If process parameter values are beyond the optimal value, the joint strength decreases due to formation of defects. Maximum tensile strength is obtained for rotational speed of 1000 rpm and welding speed of 80mm/min. © 2017 Trans Tech Publications, Switzerland.Item Application of neural network for the prediction of tensile properties of friction stir welded composites(Trans Tech Publications Ltd ttp@transtec.ch, 2017) Shettigar, A.K.; Prabhu B, S.; Malghan, R.; Rao, S.S.; Herbert, M.In this paper, an attempt has been made to apply the neural network (NN) techniques to predict the mechanical properties of friction stir welded composite materials. Nowadays, friction stri welding of composites are predominatally used in aerospace, automobile and shipbuilding applications. The welding process parameters like rotational speed, welding speed, tool pin profile and type of material play a foremost role in determining the weld strength of the base material. An error back propagation algorithm based model is developed to map the input and output relation of friction stir welded composite material. The proposed model is able to predict the joint strength with minimum error. © 2017 Trans Tech Publications, Switzerland.Item Experimental study on linear displacement measurement sensor using RGB color variation technique with PID controller(Institute of Electrical and Electronics Engineers Inc., 2017) Murthy, A.; Rao, S.S.; Herbert, M.A.; Karanth P, P.This study is based on experimental approach to linear displacement measurement using RGB color coding algorithm. This system is based on the auto-calibration procedure which can be implemented in a circuit, based on the temporal changes in the intensity of light, with the help of a light dependent resistor (LDR). The system consists of two LDRs and an LED placed on one side and an RGB color coded reflective paper on the opposite side. PIC microcontroller is used for powering the LED, processing of data for feedback control and to display the output on an LCD. LDR1 reading is used for displaying the relative linear distance, by mapping the voltage as a function of distance. This reading is used as a feedback to a PID controller to correct for the deviation in the measurement. Extensive experimental observations are conducted to analyze the reliability of the results in accordance to the wavelength of light reflected, the signal voltage and power output of the system. Investigation of the optimum positioning of the LED and the reflective RGB color coded paper is performed by repeatability analysis and hysteresis effects. Furthermore, the efficiency of the system is increased by implementing a PID controller upon investigating the different controller design, viz. P, PI and PID. A high resolution of 0.1 [mm] is obtained for such a simple and economical system, thereby making it highly efficient, in both minute measurements as well as over the entire bandwidth range of the visible light spectrum. © 2017 IEEE.Item Influence of modified cutting inserts in machining of Ti-6Al-4V alloy using PCD insert(Elsevier Ltd, 2018) Rao, R.; Rao, S.S.; Herbert, M.A.In modern manufacturing industries, the emerging needs of modern metal cutting operation are to increase the tool life with good surface finish and higher material removal rate. These objectives can be achieved by reducing the cutting temperature at the cutting zones with proper cooling system. The present work involves the experimental study of MQL application through the micro-holes drilled on the cutting inserts during turning of Ti-6Al-4V alloy using PCD inserts. The effect of the micropool lubrication of cutting insert on cutting temperature, surface roughness and tool wear have been compared with normal insert machining. It has been observed that in micropool lubrication method, cutting temperature was reduced by 30-33% over normal insert machining. Micropool lubrication reduced the flank wear to a maximum of about 20-30% over normal insert machining. The experimental result of the current research work indicates considerable benefits of surface roughness and tool wear through reduction in cutting temperature due to the perforation of the cutting insert. © 2018 Elsevier Ltd. All rights reserved.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.