Numerical and Experimental Analysis of Surface Roughness during the Milling Operation of Titanium Alloy Ti6Al4V

Abstract

Titanium alloy (Ti-6Al-4V) has many industrial applications due to its excellent mechanical properties. However, its low thermal conductivity often results in surface and dimensional inaccuracies during machining operations. In this study, an experimental investigation was done to characterise the influence of milling parameters on the surface roughness of Ti-6Al-4V. The numerical experimentation involves the use of the Response Surface Methodology (RSM) with three factors namely: the speed, feed and depth of cut. The physical experiments were carried out using a DMU80monoBLOCK Deckel Maho 5-axis CNC milling machine and a carbide-cutting insert (RCKT1204MO-PM S40T). The comparative analysis of the results obtained indicate that the milling parameters and cutting conditions significantly influenced the surface finish of the titanium alloy. The results obtained from the physical experiments indicate an increase in the magnitude of the surface roughness when the cutting parameters exceed their optimal values. The machining parameters which resulted in the least surface roughness (Ra: 0.035 µm, Rz: 1.12 µm and Rq: 0.277 µm) under the air cooling condition were: cutting speed (265 m/min), feed per tooth (0.05 mm) and depth of cut (0.5 mm). Information on the effect of machining parameters on surface roughness will assist manufacturers in selecting the most feasible combination of the process parameters for producing titanium alloy (Ti-6Al-4V) parts with improved surface quality