Effect of Print Orientation on Sintering Shrinkage of BMD 316L Stainless Steel: An Empirical and Numerical Study

This study empirically and numerically investigates sintering-induced shrinkage of 316L stainless steel cylinders fabricated via Bound Metal Deposition (BMD). Sintering shrinkages were measured for three cylindrical specimens, one each in x-, y-, and z-print orientations, via a dilatometer. Each specimen was horizontally sintered to 1360 °C via a prescribed temperature profile to maintain identical sintering conditions between specimens. Numerically, a two-dimensional axisymmetric finite element model was implemented in Abaqus using a user-defined viscoplastic constitutive model incorporating porosity- and temperature-dependent viscosities, grain-growth kinetics, and capillary-driven sintering stress. Model parameters were calibrated using particle swarm optimization by minimizing a combined error metric for temperature-dependent shrinkage responses and final relative densities. Results indicate: (1) final shrinkages of 13.5%, 13.7%, and 14.3% for the x-, y-, and z-oriented specimens, respectively, and (2) the optimized numerical model utilizing literature-informed material property constraints results in shrinkages and final densities that are in good agreement with empirical observations. Importantly, this work (1) suggests sintering shrinkage may depend on print orientation, in addition to furnace orientation, for BMD-fabricated 316L stainless steel, and (2) adds an initial dilatometer data set for BMD 316L to the literature. More broadly, this work supports future design activities via an experimental and numerical characterization of sintering behavior.