Product Code: ICA12_M1004

From ps to fs: Dependence of the Material Removal Rate and the Surface Quality on the Pulse Duration for Metals, Semiconductors and Oxides
Authors:
Beat Neuenschwander, Bern Univ. of Applied Science, Institute of Applied Laser, Photonics and Surface Technologies; Burgdorf Switzerland
Beat Jaeggi, Bern Univ. of Applied Science, Institute of Applied Laser, Photonics and Surface Technologies; Burgdorf Switzerland
Marc Schmid, Bern Univ. of Applied Science, Institute of Applied Laser, Photonics and Surface Technologies; Burgdorf Switzerland
Presented at ICALEO 2012

Ultra short laser pulses are the best choice when high requirements concerning accuracy, surface roughness, heat affected zone etc. are demanded. With the reported promising results the interest for applications has significantly increased. However, beside the machining quality, also the process efficiency is a key factor for the successful transfer of this technology into real industrial applications. It has been shown that for ultra short pulses a maximum removal rate per average power can be achieved with an optimum setting of the laser parameters which is finally given by the threshold fluence and the energy penetration depth. Both material parameters depend on the number of pulses applied and the pulse duration. For copper, steel and brass the higher energy penetration depth for shorter pulses leads to an increase of the removal rate of up to 75% (when the pulse duration is reduced from 10 ps to 500 fs). The results of a further systematic study for other materials (including silicon, fused silica, polycrystalline diamond and zirconium oxide) will be presented and the influence of the pulse duration onto the process efficiency and the surface quality will be discussed.