Binder Jet 3D Printing of Magnesium Oxychloride Cement-Based Concrete: A Framework to Design the Rate of Voxel

The present work addresses the powder bed binder jet 3D printing as an additive manufacturing process for cement-based materials in the constructions industry. Features are created through the interaction among the droplets of the liquid binding agent and the layered powder bed. The printhead movement over the powder bed at a given feed rate forms voxels and single-lines from the coalesce of successive droplets and adjacent lines are consolidated to create the designed cross-section. Here, statistical models have been developed to study the effect of printing parameters (aggregate particle size, feed rate, velocity of powder spread, pressure of the fluid and nozzle diameter) on the resultant dimension of a single printed line, using a factorial design of experiment. The hardware of the 3D printer, the physical properties of the powder blend and binder are initial constraints for designing voxels. Linear regression models of significant parameters are presented. Pressure is one of the most significant factors, it has a profound effect on the granule formation mechanism. Cubic samples printed with higher pressure level are characterized by higher residual porosities from crater channels during the printing process. The results demonstrate a fundamental understanding of the binder–powder interaction for cementitious materials which can be leveraged to determine the minimum printable feature with required dimensional accuracy, based on the chosen process parameters.