Finite Element Analysis of Thermal Stress and Thermal Deformation in Typical Part during SLM

Abstract

Selective laser melting (SLM) constitutes an additive manufacturing (AM) method. Many issues such as thermal strain and macro-thermal deformation, which are caused by the thermal stress of different process parameters, are not clear. In this paper, an efficient and fast manufacturing simulation method was researched based on a moving heat source model and an elastoplastic theory of welding simulation, which was studied based on the thermodynamic coupling algorithm with a software-developed application for the SLM process. Subsequently, typical case results of thin and hollow plate part formation and the corresponding performances were simulated in detail. The results demonstrated that the effective thermal stress increased as the layer height increased from the surface layer to the substrate, while the thermal strain followed an approximate change rule. In addition, the stress was released from the underlying substrate when the support was removed. Moreover, the largest single axis plane stress was changed from tension to compression from the edge to the center, finally reaching equilibrium. In particular, maximum macro thermal deformation occurred at the printed support structure to the samples, displaying similar results in other locations such as the corners. Finally, the effectiveness of the simulation could be verified from the realistic printed part, which could provide proof for the quality prediction of the part that is actually forming.

Keywords

• additive manufacturing
• moving heat source
• elastoplastic theory
• thermodynamic coupling algorithm
• experimental verification