Computation of temperature fields

Laser material processing is inherently associated with changes of the thermal state of materials including phase changes such as melting and evaporation. These are necessary to reach the objective of a particular process, for example the generation of a cut kerf in laser beam cutting or the creation of a weld joint in laser beam welding. The temporal and spatial development of the heat flow is of crucial importance for the quality of the processing results. This is a matter of fact for the direct process zone (in which the change of thermal state is required) and for adjacent regions that might suffer from thermal damages as a result of the stimulated heating up and cooling down during the process. Thus, it is of particular interest to know the thermal regimes and how these can be affected by proper process design and control.

The simulation is a very comprehensive tool for predicting the spatial and temporal development of a temperature distribution. To give some examples, Figure 1 shows the temperature field in a thin-section steel sheet during high-speed material treatment. Figure 2 demonstrates the temperature field of a laser beam welding process with particular consideration of the clamping conditions. Reliable statements about the local and global thermal loads of processed workpieces can be derived as a result of those computations. In addition, appropriate simulation models offer the capability to perform virtual low-cost parameter studies and/or sensitivity analyses with the objective of process optimization.