Abstract
Drillablity derived from term of machinability, which is applied in drilling. In this study, drillability of titanium alloy 6246 has been investigated through observation of two responses of drilled holes quality, i.e. surface roughness and holes roundness. Taguchi L18 Design Experiment-based approach was used to gain an optimum setting of five drilling parameters: coolant, heat treatment variation, depth of drilling, cutting speed and feed rate. The tool used was TiAlN coated carbide drill insert. Minitab 17 was employed for processing the data; analysis of S/N ratio to find effect of each parameter and ANOVA were employed for analysing the significant of each parameter to the surface quality respectively. ANOVA shows that depth of drilling contributes 55% to the roughness, followed by heat treatment (25%), while coolant only affects the roughness quality by 2%. All the 5 parameters chosen in this research has no statistically significant effect to the roundness. The predicted optimum value of surface roughness of between 0.591 µm to 0.803 µm would be achieved when drilling Ti-6246 at a maximum depth of 10 mm, without coolant, cutting speed of 35 m/min and feed rate of 0.08 mm/min on the as received block.
