Zusammenfassung
Drilling of deep, diffuser-shaped microholes in thick steel plates with ultrashort-pulsed lasers is still a challenge. With constant laser parameters
the process parameters change with increasing hole depth leading to stagnation of the drilling depth and requiring depth-adapted strategies to
allow efficient drilling. In the present work, optical coherence tomography (OCT) was used for in-situ, time-resolved acquisition of the hole depth
during laser drilling with ultrashort laser pulses. The OCT-based measurements were validated by comparing the number of pulses necessary for
breakthrough as measured with OCT with the number of pulses measured camera-based to drill through holes in steel plates of various thickness.
The online-determination of the drilling progress allowed to apply a depth-adapted drilling strategy in order to drill conically-shaped microholes
in steel with a depth of up to 10 mm.
Nutzer
