Ultrafast scan techniques for 3D-m structuring of metal surfaces with high repetitive ps-laser pulses

Metals and other materials can be machined with surpassing quality and highest flexibility with high power ultrafast lasers. In this study a slab based MOPA ps-laser system with fluencies of up to 30 J/cm2 and pulse repetition rates in the multi MHz range for processing of large embossing metal rollers has been investigated. Different materials (Cu, Ni, Al, steel) have been explored for parameters like ablation rate per pulse, ablation geometry, surface roughness, influence of pulse overlap and number of loops. An enhanced ablation quality and an effective ablation rate of 4 mm3/min has been achieved by using different scanning systems and an optimized processing strategy.