Enhanced processing speed in laser drilling of stainless steel by spatially and temporally superposed pulsed Nd:YAG laser radiation

Percussion drilling through holes in stainless steel (1.4301, 5, 8, and 10 mm in thickness) was performed with the superposed radiation of two pulsed Nd:YAG lasers. Holes were drilled with flash lamp pumped Nd:YAG slab-laser radiation with a pulse duration of 0.5 ms superposed with diode-pumped solid-state (DPSS) laser radiation with a pulse duration of 17 ns. The drilling efficiency is improved by the spatially and temporally superposed radiation of the two lasers. With the superposed laser radiation, drilling through stainless-steel samples at a maximum aspect ratio of 60 is performed up to four times faster with the reproducibility of the drilling time improved by a factor of six in standard deviation.