Finite Element Analysis And Scanning Strategy Optimization Based On Selective Laser Melting

Selective laser melting(SLM) is the most sophisticated additive manufacturing(AM) technology. It has got a lot of attention. Nevertheless, SLM is still in the research phase. Only a few types of materials have been used in SLM. It limits the forming precision of SLM components because of the less understanding of the temperature and stress distributions of Ti6Al4 V in SLM process. At the same time, scanning strategy optimization need to be further studied. In SLM process, undesired distortions are much more likely to occur in forming pointed cross-section shape of Ti6Al4 V parts due to high temperature gradients and thermal stresses. In order to improve forming precision and ensure the normal SLM process, the distribution of temperature field must be control effectively. The suitable scanning strategy can reduce temperature gradient. Therefore, In order to reduce the warp deformation of pointed cross-section shape, it is necessary to optimize scanning strategy.In this study, numerical simulation technique is employed to research the suitable scanning strategy for the special cross-section shape of Ti6Al4 V alloy powder in the SLM process.First of all, a three dimensional finite element thermal model which based on ANSYS software is proposed to study temperature variations and pool shapes of Ti6Al4 V with different scanning lengths. It is proved that the theoretical full dense parts can be fabricated with the listed process parameters in this paper.Then, stress and strain features of Ti6Al4 V powder in SLM process with different scanning lengths are got through indirect coupled thermal-structural analysis. It is found that the deviations of thin-walled parts are approximately proportional to the scanning lengths.Again, finite element analytical model is revised by comparing the experiment data and simulation results. The finally simulation and experiment results fit well, so the analytical model can be used for process parameters optimization. The most suitable scanning length is 5mm for thin-walled component with using the specified process parameters through analyzing experiment data, in which case the shrinkage per unit is close to zero.Finally, it is found that in-spiral scanning strategies is the suitable scanning method for the pointed cross-section shape by comparing the temperature ranges, standard deviations, number of molten state nodes, the maximum temperature gradients and average temperature gradients of five different scanning strategies through the finite element analysis.