190 Int. J. Experimental Design and Process Optimisation, Vol. 5, No. 3, 2017 Copyright © 2017 Inderscience Enterprises Ltd. Mathematical modelling and numerical optimisation of machining parameters for the CNC end milling process using response surface methodology Boppana V. Chowdary*, Mitra Kisraj, Kuldeep Ojha and Fahraz Ali Department of Mechanical and Manufacturing Engineering, The University of The West Indies, St. Augustine, Trinidad and Tobago Email: chowdary.bv@gmail.com Email: mitra.kisraj@my.uwi.edu Email: kojha.gvc@gmail.com Email: fadeed@gmail.com *Corresponding author Abstract: This study applies response surface methodology (RSM) to optimise the machining parameters for minimum surface roughness in the end milling process for 5083 aluminium workpiece using high-speed steel cutting tools. The combination of parameters investigated and varied in this research work was spindle speed, feed rate, depth of cut and diameter of tool. The central composite design method was used to reduce the number of experimental runs, whereas modelling and analysis with RSM were performed to obtain the objective function for surface roughness. Furthermore, optimisation of the objective function for surface roughness was performed. The results indicated that the determined optimal combination of machining parameters improved the performance of the machining process. Keywords: CCD; CNC; machining; milling; optimisation; RSM. Reference to this paper should be made as follows: Chowdary, B.V., Kisraj, M., Ojha, K. and Ali, F. (2017) ‘Mathematical modelling and numerical optimisation of machining parameters for the CNC end milling process using response surface methodology’, Int. J. Experimental Design and Process Optimisation, Vol. 5, No. 3, pp.190–205. Biographical notes: Boppana V. Chowdary is a Professor and the Head of the Department of Mechanical and Manufacturing Engineering, The University of the West Indies, Trinidad and Tobago. His research interests include production technology, product design and development and CAD/CAM. Mitra Kisraj is graduated with a BSc in Mechanical Engineering in 2015 at The University of the West Indies, St. Augustine Campus, Trinidad. His research interests include the areas of product design and development and CNC machining. Dr Kuldeep Ojha has joined The University of the The West Indies in year 2016 as a Lecturer. He has about twelve years of industry, teaching and research experience. He is currently involved in research work in the field of electrical discharge machining, renewable energy management and lean manufacturing. He published 21 research papers in international journal and