Development of three-dimensional thermomechanical finite element model for prediction of thermal deformation during selective laser sintering processes

The main advantages of 3D printing (additive layer manufacturing) over conventional methods are that it reduces costs by eliminating the need for tooling, enables faster production of prototypes and goods, and reduces waste because the excess powder can be reused. A common method for 3D printing using metal powder is selective laser sintering (SLS). In this technique, a model is created using a CAD software. A laser irradiates the powder and partially melts it layer by layer until the shape of the object is formed. Then, the liquid powder solidifies into the final object. During the phase changes, a temperature difference gradient between layers causes residual thermal stress. This thermal stress leads to shrinkage and warpage in the final products. In this paper, a transient 3D thermo-mechanical model using finite element analysis (FEA) is applied in order to study thermal deformation in the partial melting process. The thermal deformation analysis is presented at different running times. The results for the thermal deformation analysis show that as the time increases, the degree of thermal deformation increases. The developed model sets the basis for a more comprehensive model for processinduced defects in laser-based 3D printing of metal powder.