Automatic laser based material identification and marking, a new approach

Laser-Induced Breakdown Spectroscopy (LIBS) is a remote, online, in situ technique used for the quantitative analysis of elemental constituents in matrices such as steels, non ferrous metals, polymers and soils. A typical industrial application already established is the sorting of non ferrous metals for the purpose of recycling. A new device, the Laser Identification and Marking System (LIMAS) introduced here, uses a combination of material identification by means of LIBS and instantly marking the workpiece using the same Nd:YAG laser. This method was developed since the application required a strongly decreased probability of mixing up of different steel qualities in comparison to conventional methods. At the same time a decisive disadvantage of LIBS, the insufficient detection limits for several elements, can be lowered by using repetitive bursts of multiple laser pulses.