On the possibility of steady-state solutions application to describe a thermal state of parts fabricated by selective laser sintering

Abstract

The temperature distribution during selective laser sintering of a thin vertical stainless-steel wall has been simulated. The object is grown by successive deposition and laser melting of powder layers. An adjoint problem, including calculation of temperature in the part and the surrounding operating region, has been solved for different manufacturingprocess parameters within the plane statement based on two different approaches. The first approach considers transient heat conduction problem for a layer-by-layer grown body. The height of the calculation domain increases at each calculation step due to the addition of a new powder layer and a short-term laser treatment is applied to the layer region. The duration of one calculation step is determined by the time between two laser passes. The temperature distribution found at each step is used as the initial conditions for calculations at the next step. The thermal state achieved by the object under consideration after 500 calculation steps (i.e., after deposition and melting of 500 layers) is compared with a corresponding solution to the quasi-steady-state problem, which is found for a final geometry of the part, provided that a constant time-averaged heat flux is set to be supplied to the synthesis region. By example of the simple geometry under consideration, a quasi-steady-state solution can provide a fairly good estimate of the macroscopic thermal state of the synthesized part.