Percussion drilling is a well-established technique for several applicative markets such as for aircraft and watch
industries. Lamp pumped solid state lasers and more recently fiber lasers, operating in millisecond or nanosecond
regimes, are classically used for these applications. However, due to their long pulse duration, these technologies are not
suitable for emerging applicative market such as fuel injectors for automotive industry. Only the ultrashort laser
technology, combined with special drilling optics like trepanning head, has the potential to fulfill the needs for this new
market in terms of processing quality, custom-shape capabilities and short drilling time. Although numerous papers
dealing with percussion drilling have been reported in the literature, only few papers are dedicated to trepanning drilling.
In this context, we present some results on the influence of pulse duration on gas-assisted laser drilling of stainless steel
using a trepanning head and a high power Ytterbium doped fiber ultrafast laser (20W). The influence of pulse energy (7-
64μJ), fluence (3-25 J/cm2), drilling time (1-20s), processing gas pressure and drilling strategy will be discussed as well.