EFFECT OF NOSE RADIUS ON SURFACE ROUGHNESS IN CNC TURNING USING DESIGN OF EXPERIMENTS

Abstract

The present work is concerned with an experimental study of turning of Aluminium 6061 alloy on computer numerical control(CNC) machine with cutting inserts having different tool nose radii. Turning of aluminium 6061 is carried out at three different nose radius, those are 0.4 mm, 0.8 mm and 1.2 mm. Our objective of the ensuing study was to determine the effect of cutting parameters viz. cutting speed, feed and depth of cut; and one of tool geometry parameter that is nose radius on the surface roughness of the machined material that is aluminium 6061 using Response Surface Methodology. The primary objective is to find the optimum machining parameters so as to minimize the surface roughness in the chosen domain of the performed experiments. A full-factorial Central Composite Design (CCD) is used to design an experimental matrix. Talysurf surtronic 3+ is used to measure average value of surface roughness. For analysis the data was compiled into MINITAB ®17. The relationship between the machining parameters (speed, feed, depth of cut and nose radius) and the response variable (surface roughness) were modelled and analysed using the Response Surface Methodology (RSM). Analysis of Variance (ANOVA) is being used to investigate the significance of these machine parameters on the response of the factor, and to generate a regression equation for the response as dependent variable, depending on parameters which are independent variables, through the help of a quadratic model. ANOVA is also used to generate main effects and interaction plots which are studied along with contour and 3-D surface plots. Results showed that feed is the most effective factor affecting the surface roughness, closely followed by nose radius, cutting speed. The optimum settings for carrying out the machining were obtained from Response Surface Optimizer.