Effect of Different Lubricants on Small Hole Drilling in Ti-6Al-4V – A Taguchi-Grey Approach

The world is moving towards miniaturization of all systems to conserve space and energy. In this experimental investigation, small holes of 0.5 mm diameter were drilled in Ti-6Al-4V plates of thickness 0.4 mm. L18 orthogonal array, the signal to noise (S/N) ratio, and the analysis of variation (ANOVA) were employed to analyze the effect and contribution of process parameters, namely, spindle speed, feed rate, and the use of different lubricants. Drilling experiments were performed in dry, air cooled and wet lubrication (palm oil). Tool wear and hole circularity were evaluated for each machine setting using a Scanning Electron Microscope (SEM). Optimization was performed using Taguchi method and Grey relational analysis. The outcome of this study showed that palm oil can be used as an effective lubricant in order to minimize tool wear and circularity error. Multi performance optimization revealed that feed rate and lubrication were the most significant parameters in controlling circularity and tool wear.