Experimental Investigation on Influence of Nano Fluids in Drilling of Al 6061 Alloy using Grey Based- Taguchi Approach

Abstract

Drilling, a hole making process is especially important because it accounts for a large portion of overall machining operations. Amongst all machining operations, drilling using twist drill is most commonly applied method for generating holes for riveting and fastening of structural assemblies.This paper deals with multi performance characteristics in drilling of Aluminum 6061 alloy with water based Nano fluid (small amount of Al2O3 Nano particles in water) using Grey based – Taguchi method. Five parameters namely cutting speed, feed rate, point angle, clearance angle and variable volume fraction of Al2O3 Nanoparticles in water were identified and their ranges for the present investigation were determined from preliminary experiments. Thrust force and surface roughness are recorded using well calibrated equipments at 3 levels with L27 orthogonal array as per Taguchi experimental plan. Optimal combination of process parameters was obtained to minimize the recorded responses. In the case where experiments are ambiguous or when the experimental method cannot be carried out exactly, grey analysis helps to compensate for the shortcoming in statistical regression. Grey based – Taguchi method is an effective tool for analyzing the relationship between sequences with less data and can analyze many factors that can overcome the disadvantages of statistical method. Most of manufacturing industries perform a huge number of drilling operations in machine shops. The drilling technology has been studied to improve the cutting performance with optimizing the cutting parameters and the tool geometry. Some researchers have developed mathematical models of drilling to estimate thrust and torque. Williams [1] showed that during cutting there are three identifiable zones of interest at the drill point, the main cutting edges, the secondary cutting edges at the chisel edge and an indentation zone about the drill center. Zhang et al. model was based on mechanics of vibration and the continuous distribution of thrust and torque along the lip and the chisel edge of the twist drill [2]. The mean thrust and torque increased as feed increases under constant vibration parameters [3–4]. They concluded that vibration drilling is different from conventional drilling and it is a dynamic cutting process. Another model was presented for drilling processes by Yang et al. [5]. A statistical analysis of hole quality was performed by Furness et al. [12]. They found that feed and speed have a relatively small effect on the measured hole quality features. With the expectation of hole location error, the hole quality is not predictably or significantly affected by the cutting conditions. Although the authors did not expect these results, they have the important positive implication that production rates may be increased without sacrificing hole quality. Rincon and Ulsoy[15] showed that the changes in the relative motion of the drill do affect the variations of the forces. An increase in the ranges of drill motion results in an increase in the ranges of torque and thrust. The 6061 alloy of aluminum is primarily composed of magnesium and silicon. Some other elements of 6061 aluminum alloy include small amounts of iron, copper, manganese,