Experimental Modelling of Nd:YAG Laser Percussion Drilling Process of Ti6Al4V Alloy

Laser percussion drilling is one of the advanced drilling processes that its numerous advantages have extended the applications of this process. This study focuses on experimental investigation of laser percussion drilling using Nd:YAG laser on titanium alloy Ti6Al4V sheets with various thickness which is widely used in industry. In this paper the effects of the input parameters peak power, pulse width, frequency, assist gas type, gas pressure and sheet thickness on the most important process outputs include hole entrance diameter, hole exit diameter, hole taper angle, hole entrance circularity and hole exit circularity were studied. Statistical analysis was employed to analyze the experimental data and significant parameters in each response are presented. For conducting the experiments “Design of Experiments” method and for modelling “Response Surface Methodology” were used. The results obtained show that sheet thickness affects all outputs. After that frequency and pulse width, peak power and assist gas type respectively are the most significant parameters influence process outputs. Gas pressure only affects the hole entrance circularity. For this alloy to achieve a hole with high quality, it is recommended to work at lower peak power and frequency, shorter pulse width and higher assist gas pressure with Nitrogen as assist gas.