PROCESSING OF INDUSTRIALLY RELEVANT NON METALS WITH LASER PULSES IN THE RANGE BETWEEN 10PS AND 50PS

摘要

In materials processing pulses in the ps range are an excellent tool to achieve high precision. Although for metals even shorter pulses would be desirable, the lower ps range is attractive from the point of view of the availability of industrial grade systems. In that sense we have analyzed metals and found that the increase of the pulse duration from 10ps to 50ps directly goes along with a significant drop of the maximum achievable volume ablation rate which may reduce the attractiveness of systems with pulse durations in the range of a few tens of ps. The situation changes for non metals like ceramics, polyether ether ketone (PEEK) and polycrystalline diamond (PCD). For PEEK and PCD the dependence of the ablation efficiency on the pulse duration in the investigated regime is strongly reduced. Silicon again shows a metal like behavior, which seems to be independent from the doping level. The porous form of the chosen zirconium oxide ceramic thwarted a systematic study to determine the threshold fluence and the energy penetration depth at the used laser wavelength of 1064 nm. Nevertheless it was possible to machine small structures into the zirconium oxide. The obtained results show, that laser systems with pulse durations in the range of a few tens of ps, which are expected to be fiber based and cost effective, may be a very attractive alternative to machine industrially relevant non metals.