Engineering Anisotropic Porosity in Green Parts from Binder Jet 3D Printing

Binder Jet Additive Manufacturing (BJAM) is a promising metal additive manufacturing technique that enables the fabrication of complex geometries without the need for support structures. However, the inherent porosity in green parts, remains a challenge in achieving desired mechanical properties and performance. Instead of treating porosity as a limitation, this thesis explores engineering of anisotropic porosity engineering, where controlled variations in porosity in the green parts can be used to enhance functionality and efficiency in specific applications. The objective of this research is to investigate and analyze the key print parameters that influence green part density. By systematically varying layer thickness, binder saturation, and powder bed characteristics, experimental results reveal that layer thickness has the most significant impact on porosity. To complement the experimental work, a Discrete Element Method model is developed to simulate the single-layer powder bed formation process in BJAM. This computational approach provides insights into how powder particle interactions and binder infiltration contribute to porosity formation. The DEM results are correlated with experimental data to enhance process predictability and establish a framework for optimizing porosity control in BJAM.