Short pulse high intensity laser machining

Recent developments in the study of drilling and cutting performance of metals, ceramics, and composites are reviewed. Machined quality comparisons are made using a high brightness Nd:YAG laser and an ultrafast Ti:sapphire laser, with pulse widths ranging from 100 ns to 100 fs. Significant qualify improvements are achieved over that of conventional Nd:YAG lasers at about 1 ms pulse width. It is shown that the shortening of pulse length and the subsequent increase in beam intensity result in much thinner recast layers and heat affected zones (HAZ), less microcracking or delamination of materials, and much better geometry stability. Both the Nd:YAG fundamental 1064 nm and the second harmonic wavelength of 532 nm are tested, showing substantial additional advantage for the shorter wavelength.