Determination of the Accuracy of Holes produced by Deep Drilling of Ti-6Al-4V Titanium Alloy

Abstract

Deep drilled holes in titanium alloys are broad in terms of the engineering and fabrication application in various products. The accuracy of deep drilling, tool wear, chip morphology and hole surface-wear are determined in this study. A sequence of machining tests were conducted to examine the deep drilling of Ti6Al4V alloy behaviour. Furthermore, a model that describes and improves the accuracy of holes in deep drilling of Ti6Al4V using High Speed Steel (HSS) drills was investigated, with the upshot of cutting limits on process indicators on tool wear and chips for modern manufacturing industries. The factorial design methodology for experiments was employed to investigate the influence of the cutting parameters on hole accuracy. Drilling were carried out on a solid cylindrical shaft of titanium alloy Ti-6Al4V using a 5-axis, Computer Numerical Control (CNC) milling machine and 13 piece of 10 mm diameter drill bits made from HSS Co and DMU 80 monoblock DECKEL MAHO. The surface corrosion and wear of the samples were also investigated using the Scanning Electron Microscopy (JEOL-SEM). The results obtained indicated that high tool wear results in short tool life when drilling at high speeds and feeds. The 10 mm HSS Co drill fails at high speeds of between 1272-640 rev/min and drill without failure at speeds of 630-318 rev/min for deep drilling of Ti-6Al-4V. The combination of 318 rev/min and 25 mm/min produces the preferred short and discontinuous chips. Thus study can assist drilling operators in obtaining accurate holes during deep drilling of Ti6Al4V.