International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395 -0056
Volume: 04 Issue: 05 | May -2017
p-ISSN: 2395-0072
www.irjet.net
OPTIMIZATION OF MACHINING PARAMETERS IN A TURNING OPERATION OF AISI 202 AUSTENITIC STAINLESS STEELTO MINIMIZE SURFACE ROUGHNESS Chandan Kumar1, Mohammad Nehal Akhtar2, Mohd Ziaul Haq3 123Assistant
Professor, Dept. of Mechanical Engineering, AIET Lucknow, UP, India ---------------------------------------------------------------------***---------------------------------------------------------------------
Abstract - The present work concerned an experimental
study of turning on Austenitic Stainless steel of grade AISI 202 by a TiAlN coated carbide insert tool. The primary objective of the ensuing study was to use the Response Surface Methodology in order to determine the effect of machining parameters viz. cutting speed, feed, and depth of cut, on the surface roughness of the machined material. The objective was to find the optimum machining parameters so as to minimize the surface roughness for the selected tool and work materials in the chosen domain of the experiment. The experiment was conducted in an experiment matrix of 20 runs designed using a full-factorial Central Composite Design (CCD). Surface Roughness was measured using a Talysurf. The data was compiled into MINITAB ® 17 for analysis. The relationship between the machining parameters and the response variables (surface roughness) were modeled and analysed using the Response Surface Methodology (RSM). Analysis of Variance (ANOVA) was used to investigate the significance of these parameters on the response variables, and to determine a regression equation for the response variables with the machining parameters as the independent variables, with the help of a quadratic model. Main effects and interaction plots from the ANOVA were obtained and studied along with contour and 3-D surface plots. Key Words: Turning, RSM, Cutting Speed, Depth of Cut, Surface roughness, CCD, ANOVA, etc.
1. INTRODUCTION The turning operation is a basic metal machining operation that is used widely in industries dealing with metal cutting. In a turning operation, a high-precision single point cutting tool is rigidly held in a tool post and is fed past a rotating work piece in a direction parallel to the axis of rotation of the work piece, at a constant rate, and unwanted material is removed in the form of chips giving rise to a cylindrical or more complex profile. This operation is carried out in a Lathe Machine either manually under an operator’s supervision, or by a controlling computer program [1]. The work piece used for the concluded experiment was AISI 202 grade Austenitic stainless steel. There are two series of Austenitic stainless steels – 300-series and 200-series. 300 series steels find most wide use around the world but 200 series have become very popular in the Asian subcontinent © 2017, IRJET
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as an alternative to the 300 series to counter the increase in prices of Nickel. Grade 202 steel can be made into plates, sheets and coils and finds extensive use in restaurant equipment, cooking utensils, sinks, automotive trims, architectural applications such as doors and windows, railways cars, trailers, horse clamps etc. Neseli et. al [2] used RSM method and Nose radius, approach angle and rake angle as the input variables and found that the nose radius has the most significant effect on surface roughness. Studies by Sahin Y. et. al.[3] have shown that surface roughness is mostly dependent on feed rate which is the dominating factor Nanavati et. al.[4]used feed, cutting speed and tool nose radius as predictors in the RSM method and determined that feed was the most significant factor affecting the surface roughness followed by the tool nose radius. A study conducted by Bouacha, showed that feed rate was the most influential parameter in determining surface finish of a product followed by the cutting speed. Surface roughness is a measure of the surface finish of a product and an index of the product quality. Surface roughness is a measurement of the small scale variations in the height of a physical surface [4]. It is expressed in various ways and methods, like arithmetic mean or centre-line average (Ra), Root-mean square average (Rq), maximum peak (Ry), ten-point mean roughness (Rz), maximum valley depth (Rv), maximum height of profile (Rt = Rp – Rv) etc. Out of all these, the most commonly used indicator for surface roughness is Ra. Ra, or the arithmetic mean value, previously known as AA (Arithmetic Average) or CLA (Centre-Line Average) is the arithmetic mean of deviations of a series of points from the centre line or datum line. The datum line is such that sum of the areas under the profile above the datum will be equal to the sum of areas below the datum. Generally, surface roughness is expressed in microns (μm). The turning operation is governed by geometry factors and machining factors. This study consists of the three primary adjustable machining parameters in a basic turning operation viz. speed, feed and depth of cut. Material removal is obtained by the combination of these three parameters.
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