Numerical Simulation of Particle Size Influence on the Sintering Behavior of 316L Stainless Steel Powders Fabricated by Binder Jet 3D Printing

Abstract

Binder jet 3D printing (BJ3DP) is one of the most promising 3D printing technologies, due to its ability of printing large-scale complex parts with high efficiency and low cost. The powder particle size is crucial for the sintering quality of BJ3DP. In this work, on the basis of the constitutive model of viscoplastic theory, the shape evolution (shrinkage and relative density) of cubes produced by BJ3DP using 316L stainless steel powders (normal distribution of powder sizes) with different mean particle sizes (i.e., 20, 30, 40, 50, 60, and 70 μm) was studied via finite element numerical simulation during sintering. It revealed that the volumetric shrinkage, relative density, and maximum sintering stress decreased with increasing the mean particle size. The maximum sintering stress of the sample with mean particle size of 70 μm was 0.0492 MPa, with the volumetric shrinkage of ~40% and the relative density of ~89%. In the meantime, the maximum sintering stress of the sample with mean particle size of 20 μm was 0.1789 MPa, with the volumetric shrinkage of ~48% and the relative density of ~97%. In addition, the simulated results of the relative density of assumed samples agreed well with the experimental results from the literature.