From fs to Sub-ns: Dependence of the Material Removal Rate on the Pulse Duration for Metals

Ultra short laser pulses are used, when high requirements concerning machining quality are demanded. The cost- effectiveness plays an important role for a successful transfer of this technology into industrial applications. Therefore systems with longer ps-pulses could offer an attractive alternative compared to short ps- and fs systems. Beside fiber based systems with ∼50 ps pulse durations also small systems with sub-ns pulses are available today. In contrast to the dramatic drop of the material removal rate when the pulse duration is raised from 10 ps to 50 ps the impact is weaker for a further increase to 540 ps and the removal rate even increases when the pulse duration is raised to 1.4 ns. As no crater formation is observed and the surface quality is better than for 1.4 ns pulses, sub-ns pulses could be an attractive alternative to machine steel compared to fiber based systems with ∼50 ps pulse duration.