An Extended Rosenthal’s Model for Laser Powder-Bed Fusion Additive Manufacturing: Energy Auditing of Thermal Boundary Conditions

Laser Powder-Bed Fusions (LPBF), a class of additive manufacturing (AM), is a promising technique for producing components with complex geometry design. However, parts fabricated by LPBF suffer from residual stresses arising due to substantial temperature gradients inherent to the process. Numerical models are unable to provide a comprehensive thermal history of the built materials efficiently due to the mismatch between the characteristic length scales and infinitesimal time steps needed for complete simulations. In the present work, an extended Rosenthal’s model is presented by considering the effects of various heat dissipation/consumption mechanisms. The modeling results of energy auditing of thermal boundary conditions for stainless steel (SS17-4PH) laser melting indicated that the total energy losses by convection, radiation, and melting are less than 20% among which, radiation is the most dominant part. A comparison of the results obtained by the extended Rosenthal’s equation with finite element numerical predictions and experimental data shows a good agreement. Also, a parametric study has been conducted to identify the influence of laser scanning velocity, beam radius, and power on the overall temperature distributions and melt geometry. The present study can pave the way for the prospective use of this methodology to conduct further investigation such as microstructure analysis and thermo-mechanical modeling which are needed to predict residual stresses and distortions.