Thermal simulation of selective laser melting made components

Through thermal simulation of Selective Laser melting (SLM), one can predict the thermal distribution over the power bed during the process without performing practical experiments. In this case, the production of a piece can be improved and the possible failure in the final part would be prevented. In SLM there is high temperature gradient which leads to imposing thermal stress due to deformation and, finally, fracture of workpiece. The duration of simulation depends on several factors such as thermal properties (specific heat and thermal conductivity) of the material (constant or temperature dependent), scan area, meshing, number of laser scan tracks, and laser scan velocity value. The simulation is done by adopting Gaussian profile to resemble the laser movement. Gaussian beam is normally used in optics, and it mathematically consists of laser power intensity. During simulation, parameters such as laser power intensity, laser radius, hatch space, scan strategies, laser scanning speed and environment temperature are investigated. The software used for simulation is Ansys version 18.2 in the workbench system which solves the heat transfer equation by finite element analysis in order to obtain the temperature distribution on the powder bed. The investigated material is Ti6Al-4V powder. Results as indicated in the literature indicate that by increase of laser power and decrease of scanning speed separately, the temperature obtained on the powder bed increases, but the order and amount of increase reached by power rise is much higher. In addition, with increasing laser power intensity, the melt pool dimensions, i.e., length and depth increase significantly. Two strategies, namely, parallel and zigzag, have been adopted to direct the path of the laser. As results indicate, for the low amount of power there is no significant difference in the maximum temperature for both strategies obtained on the power bed while for increased power the zigzag structure represents higher temperature. In general, the second and third scan paths indicate higher temperature compared to the first track since the heat produced by the laser is accumulated. As a matter of fact to understand the effect of strategies, the scan domain should be changed.