Fiber laser microdrilling of titanium and its effect on material microstructure

Pulsed fiber lasers are innovative laser sources which promise to be suitable tools for micromachining operations due to their high beam quality, strong focusability, and high productivity. In this work, percussion laser microdrilling on 0.5-mm-thick commercially pure titanium sheets making use of a nanosecond pulsed fiber laser is investigated. The work is aimed at studying the effects of the main process parameters (pulse energy and pulse frequency) on the quality features of the machined through holes, i.e., diameters, taper, circularity, and area of top spatter. Adequate regressive models are developed to define the functional relationship between the hole quality and the main process parameters. The effects of laser microdrilling on material microstructure of the regions in close proximity to the machined holes are also investigated by means of nanohardness measurements and microstructural analyses.