48 Int. J. Machining and Machinability of Materials, Vol. 20, No. 1, 2018 Copyright © 2018 Inderscience Enterprises Ltd. Experimental investigation on micro drilling of Inconel 718 super alloy T. Venkatesan*, J. Jerald, J. Cyril Pilligrin and P. Asokan Department of Production Engineering, National Institute of Technology, Tiruchirappalli-620015, India Email: venkatesan_st74@yahoo.com Email: jerald@nitt.edu Email: cyrilpilligrinj@gmail.com Email: asokan@nitt.edu *Corresponding author Abstract: Drilling is one of the material removal processes which are used in various manufacturing and assembly industries. The current growing and development technology in the drilling process is micro drilling. In this work, micro-holes are drilled on Inconel 718. The effects of various process parameters like feed, spindle speed and cutting tool diameter are used to study the response parameters like machining time, MRR, temperature and thrust force obtained during micro drilling. Experiments are carried out based on Taguchi L27 orthogonal array design using Tungsten carbide drill bit and Inconel 718 as work material. Feed rate is varied from 1 to 3 mm/min, Spindle speed ranges from 16,000 to 26,000 rpm and diameter of the tool also varied from 0.4 mm to 0.8 mm. It is observed that temperature is increasing with increase in speed and feed. When the tool diameter, feed rate and spindle speed increases material removal rate (MRR) also increases. The machining time decreases with increase in feed rate, also the cutting force increase with the increase in tool diameter, feed rate and spindle speed. The optimal combination of the process parameter is found out using grey relational analysis (GRA). Keywords: micro drilling; Inconel 718; Taguchi; diameter; speed; feed; force; temperature; grey relational analysis; GRA. Reference to this paper should be made as follows: Venkatesan, T., Jerald, J., Pilligrin, J.C. and Asokan, P. (2018) ‘Experimental investigation on micro drilling of Inconel 718 super alloy’, Int. J. Machining and Machinability of Materials, Vol. 20, No. 1, pp.48–63. Biographical notes: T. Venkatesan is a Research Scholar at the Department of Production Engineering, National Institute of Technology, Tiruchirappalli, Tamil Nadu, India. J. Jerald is working as an Assistant Professor at the Department of Production Engineering, National Institute of Technology, Tiruchirappalli, Tamil Nadu, India. J. Cyril Pilligrin is a Research Scholar at the Department of Production Engineering, National Institute of Technology, Tiruchirappalli, Tamil Nadu, India.