Modelling and Simulation

Brochure Modelling and Simulation

Brochure Modelling and Simulation

The Fraunhofer Institute for Laser Technology ILT engages in fundamental work on the description of technical processes as well as the monitoring, control and regulation of such processes.

Our core competences include the modelling of radiation sources - in particular, high-power lasers and gas discharges - as well as their application in manufacturing technology. The involved physical processes range from generation, propagation and absorption of radiation to transport processes and phase transformations induced in the material by radiation. We apply methods of computer engineering to analyse the measurement data and to monitor the processes. These include, in particular, numerical methods for simulation and visualization of the processes as well as algorithms for interpretation of measurement data.

Our experienced team includes researchers in the areas of applied mathematics, physics and computer engineering. Together, we offer our customers model-based solutions for technical tasks. We develop and analyse individual approaches based on the knowledge of our customers and our own expertise as well as the properties of existing models.

Core Competences

  • Design of resonators for gas, solid and high-power diode lasers
  • Optimization of the beam guidance in optical systems
  • Radiation propagation in gas and vapor
  • Subsonic and supersonic flows in liquid, gas and vapor
  • Mass flow and heat transfer
  • Dynamic simulation for ablating, cutting, welding and drilling
  • Modular dynamics of ultrashort pulse processing
  • Simulation of laser processing in photovoltaics
  • Control of manufacturing processes
  • Algorithms for analysis of measurement data
  • Programming of graphical user interfaces for simulation and visualization
  • Numerical methods and calculation approaches, such as the Cluster-In-Cell (CIC), Finite Element (FE), Finite Volume (FV), Discontinuous Galerkin (DG) and modelreduction methods in time-variant domains, adaptive meshing
  • Meta-modelling of physical phenomena and manufacturing processes

Cutting

The combination of diagnostics and simulation yields a systematic definition of the relationships between cut quality and cutting parameters. Through analysis of the cut quality, we can identify at least three different types of ripples and four different types of adherent dross. The formation of the various score mark and burr types can be described by a straightforward set of parameters as well as their dynamic interactions during cutting. Our vision of a cognitive cutting machine comprises intelligent configuration and systematic error diagnosis. With the cognitive cutting machine, we advance developments in cutting processes to the physical limits of the laser beam, machine and process, with a defined level of quality.

Welding

The research results in the area of cutting form the basis for optimization of the welding process and allow for model-based quality assurance, calculation of the welding distortion and analysis of the suitability of new laser radiation sources. Our team investigates the dynamics of vaporization-driven melt flow and its effects on seam shape, morphology of the upper and lower bead as well as pore formation in the weld seam in order to develop appropriate measures for model-based quality assurance.

Calculation of the weld distortion with commercially available simulation tools is not sufficiently reliable. To identify the reasons for the insufficient quality of available simulations, we investigate the structural stability of the underlying models. The influence of the dynamic processes during welding as well as the refined handling of thermo-mechanical effects are taken into account in this analytical process.

Drilling

The model creation and simulation for drilling with lasers are directed primarily at avoiding recast on the drill hole wall for a long pulse length (microseconds) and at increasing the drilling speed for a smaller pulse length (sub-picoseconds to nanoseconds). Through analysis of drilling with long pulse length, we can identify four different phenomena that interact dynamically to cause the formation of recast on the drill hole wall. In the analysis of drilling with short and ultrashort pulse lengths and higher laser beam intensity, we also take into consideration the inertia of the melt, recondensation of the vapour on the hole wall, reflection of the beam and changing of the state equation upon nearing the critical temperature.

Meta-Modelling

A meta-model is the mathematical link of experimental data that indicates the multi-dimensional relationships of relevant parameters and criteria. Meta-models are methods for analysing the structural stability of models and optimizing them in terms of multiple criteria as well as for model-based predictive control of machines. They offer insight into the parameter dependencies and limits of their processes in order to apply such knowledge to the task of process optimization.