International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056 Volume: 04 Issue: 08 | Aug -2017 www.irjet.net p-ISSN: 2395-0072 © 2017, IRJET | Impact Factor value: 5.181 | ISO 9001:2008 Certified Journal | Page 354 Taguchi based Optimization of Cutting Parameters affecting Surface Roughness in dry CNC Turning of 16MnCr5 Jitendra Kumar Verma 1 , Amit Sharma 2 1 Research Scholar, Department of Mechanical Engineering, Gaeta Engineering College, Panipat, Haryana 2 Assistant Professor, Department of Mechanical Engineering, Geeta Engineering College, Panipat, Haryana ----------------------------------------------------------------------***--------------------------------------------------------------------------- Abstract- The aim of this research work is to investigate the effects of cutting parameters such as cutting speed, feed rate and depth of cut on surface roughness in CNC dry turning of 16MnCr5 material which is case hardening steel with the help of Design of Experiments. Experimental work has been carried out based on Taguchi L 27 orthogonal array design with three cutting parameters. Optimal cutting conditions were determined using the signal-to-noise (S/N) ratio which was calculated for roughness average (Ra) according to the smaller-the-better approach. The experimental results were analyzed by using main effects plots and response tables for S/N ratio. Result of this study shows Depth of cut has highest dominant factor for surface roughness followed by speed and Feed rate. Keywords: Surface Roughness, Turning, Taguchi, Regression, ANOVA 1. INTRODUCTION Quality of a machine part depends on parameters like surface roughness, dimensional accuracy, tolerance zone etc. Surface roughness plays most important role in performance of machine component and one most important thing is life of component. A component which has smooth surface has minimum chances to start a breakage of component compare to component which has surface irregularities because there is stress concentration at irregularities on surface of component which has low surface roughness. And also component which has good surface finish always subjected to low wear and tear during its functioning and also offer low friction between two matching surfaces. Due to all of the above reasons a manufacturer always tries to produce a machine component with minimum surface roughness. Srinivas Athreya and Y. D. Venkatesh [1] worked on lathe facing of mild steel. The objective of his work was to obtain optimum cutting conditions to get minimum surface roughness in facing of mild steel. Taguchi method was applied in this experimental design work. From the experiment it was finalised that, cutting speed has the most significant role on quality of surface roughness followed by depth of cut. Dilbag singh and P. Venkateswara Rao [2] investigated how surface roughness in AISI 52100 steel is affected by cutting conditions and tool geometry. They concluded that surface roughness is most significantly affected by feed rate, followed by nose radius and cutting velocity. Mathematical model developed with the help of RSM. K. Adarsh kumar et al. [3] performed research work to analyze, how surface finish of EN-8 is affected by speed, feed, depth of cut on the basis of multiple regression analysis and analysis of variance. Y. Kevin Chou, Hui Song [4] established a model to analyze the chip formation forces. Increasing cutting speed and feed rate adversely affect maximum temperature of machined surface in new cutting tool but increasing depth of cut favourably affect the maximum temperature of machined surface. S. Arul et al. [5] worked on optimization of machining parameters of glass fiber reinforced polymer. The data of machining parameters, tool life, thrust force and torque was analysed and optimized by using a algorithm which is based on group method data handling system. M. P. Jenarthanan [6] performed an experimental work to investigate the machining parameters in milling operation of glass fibers reinforced plastics (GFRP). For this tool used were solid carbide end mill tools. It was observed that, Feed rate was the machining parameter that has the highest influence on specific cutting force and surface roughness followed by the helix angle of the cutter. K. Shihab et al. [7] investigated the effect of machining parameters cutting speed, feed rate and depth of cut on surface roughness and micro hardness of hardened AISI 52100 steel for dry turning operation. It was finally concluded that the most dominant cutting parameter for the quality of surface roughness is feed rate and for micro hardness the most significant cutting parameter is cutting speed. R. Suresh et al. [8] conducted experimental work on AISI 4340 steel with the help of RSM method. They concluded that to minimise surface roughness and cutting forces, it is necessary that low feed rate, high cutting speed, low depth of cut and short machining time are employed and to minimize tool wear low cutting speed and low feed rate required. S. Z. Chavoshi and M. Tajdari [9] worked on AISI 4140 steel by using CBN cutting tool on lathe machine. They analysed that hardness has most significant effect on roughness of surface produced after machining operation. Anil Gupta et al. [10] performed a research work and concluded that, the cutting speed of 160 m/min, feed 0.1 mm/rev, nose radius 0.8 mm, the depth of cut of 0.2 mm and a cryogenic environment are the most favourable machining parameters for the turning of AISI P -20 steel on CNC. Sahin et al. [11] worked on a model of the surface roughness for machining of mild steel by using TiN-coated