Laser-Material-Interaction

The interaction between laser radiation and engineering materials forms the cornerstone of many modern manufacturing processes. In the research field “Laser-Material-Interaction” a fundamental understanding of this interaction is acquired by radiation absorption measurement.

Aim

The laser-material-interaction for engineering materials under real processing conditions in laser welding or powder bed fusion, where several phase changes occur is not yet fully understood. As the tremendous energy input in the material in a small time and space scale renders the laser-material interaction a complex and highly dynamic mechanism. But this interaction, or rather the resulting radiation absorption, governs the process behavior during the manufacturing and in turn its stability and outcome quality. For this reason, we aim to analyze the laser-material interaction for engineering materials and real manufacturing processes in real time, to develop a fundamental understanding of this mechanism. This understanding can mitigate the cost and required time of designing laser material processing processes from scratch.

Methodology

Instead of evaluating the effect of every individual process parameter on the process result, we monitor the laser radiation absorption, as a result of the laser-material interaction. The level of absorption is characteristic of different process regimes and can therefore be facilitated to identify the prevailing regime. Furthermore, we are in the process of linking the different process regimes to varies properties of the manufactured part. In this way the absorption measurement can be employed to evaluate a process regarding probable process result quality.

Our focus is on

  • laser welding and
  • laser based powder bed fusion of metals,

because these processes exhibit similar process regimes.

Vision

Currently, the common practice is to identify suited process parameters for a given process by the means of extensive experimental investigation. Replacing this labor-intensive process by a fundamental understanding of the laser-material-interaction, the cost and required time of designing laser material processing processes for novel radiation-material-combinations from scratch can be mitigated.