An analysis on the effect of machining parameters on surface quality during dry machining of Ti-6Al-4V alloy

Nowadays Titanium and its alloy materials are highly preferred for the parts of aircraft structures due to their unique properties such as good corrosive resistant and higher strength to weight ratio is sustained even at increased temperature. Even though these alloy materials are wicked for its low thermal conductivity and categorized as hard to machine alloys. Drilling of titanium alloys is a critical machining process in the fields such as medical, automobile and defence applications. In this alloy Ti-6Al-4V alloy is generally used for parts that need higher reliability therefore, surface finish and various failure to the adjacent surface layers of machined areas must to be resolved as per the customer requirement. This research work focuses on experimental study and optimization of machining parameter during dry drilling of titanium alloy (grade 5). An 8 mm diameter and 120 degree point angle solid carbide drill bits are used to carry out the experiments. The range of drilling spindle speed chosen for the experiment was between 20 to 50 m/min also feed rates were 0.05, 0.1, 0.15, and 0.2 mm/rev. Experimental analysis was done by focusing on surface roughness, circularity, hole diameter and exit burr for maintaining good quality hole. A Portable surface roughness measuring device was utilised to find surface roughness in the direction of feed on work piece material. Circularity and diameter of the machined hole was found by co-ordinate measuring machine (Contura-G2-Zeiss). From this experimental investigation it is found that feed has higher significance on surface finish when compared to drilling speed but when considering the circularity error speed has higher significance. Optimization and validation of experimental results was done by using the application of Taguchi' sdesign of experiments with signal to noise ratio graph and ANOVA. (C) 2019 Elsevier Ltd. All rights reserved.