Parametric Analysis Of Laser Beam Percussion Drilling For Thin Titanium Alloy Sheet Using Yb: Yag Fiber Laser

Laser beam percussion drilling (LBPD) can create high density holes in aerospace materials with the repeated application of laser pulses at a single spot. In this study, one-parameter-at-a-time approach has been used to investigate the individual effect of peak power, pulse width and pulse frequency on geometrical accuracy and metallurgical distortion during LBPD of 0.85 mm thick Ti-6Al-4V sheet using 200 W Yb:YAG fiber laser. It has been found that the output parameters behave differently at the higher and lower values of a particular input process. The increase of pulse width from 1 to 1.50 ms increases hole taper by 20% whereas the same corresponding change from 1.50 to 2.00 ms reduces the taper by 20%. The increase of pulse frequency from 10 to 50 Hz reduces hole circularity by 40% but the same proportionate change from 50 to 90 Hz reduces circularity by 79%. Increase of peak power from 1.70 to 2.0 kW increases hole taper by 8% but the corresponding increase from 2 to 2.30 kW is 143%.