3D Printing by Selective Binding in a Particle Bed: Principles and Challenges

Binder Jetting 3D Printing of Magnesium Oxychloride Cement-Based Materials: Parametric Analysis of Manufacturing Factors

“…Most of the previous research into binder jetting investigated the optimization of processes in which metal powders were used. For the "selective binding" of aggregates method that is of interest in this article, two different techniques are proposed: "cement paste intrusion," where a cement suspension is deposited on the powder bed for hardening, and "selective cement activation," where an activator binder is dispensed on a cement-aggregate mixture layer [9,15,38]. Unfortunately, no results are available in the literature about optimizing the properties of binder jet 3D printing cement-based materials or the modulus of rupture, which could assist engineers in designing material performance [39].…”

“…The effects of the significant factors and their interactions are discussed i section. Understanding the distribution of binder inside the powder bed is bene because it is a fundamental aspect of forming homogenous and monolithic rVs [15,4 The nozzle movement over the powder-bed jets multiple droplets; the instant b droplets impact the powder and the cement reaction initiates to bond aggregates. recognized granule formation mechanisms are tunneling, spreading, and formation, which are determined by droplet kinetic energy, aggregate particle size powder-bed density [51,52].…”

“…The effects of the significant factors and their interactions are discussed in this section. Understanding the distribution of binder inside the powder bed is beneficial, because it is a fundamental aspect of forming homogenous and monolithic r V s [15,49,50].…”

“…As the liquid penetrates into powders containing large macro-voids, the liquid front tends to halt when the pore radius suddenly increases [56]. Depending on pore size and surface chemistry of the particles, four possible paths for the binder fluid penetration can be identified: (1) no liquid absorption by the powder bed, (2) trapping of liquid on the top of the deposited layer, (3) liquid descending to the bottom of each layer, and (4) liquid spreading through the powder bed (Figure 9c) [15,54,56].…”

“…The binder jetting printing process consists of three iterative steps: (1) spreading powder over a platform; (2) the selective deposition of a liquid bonding agent onto the powder, utilizing a printer head; and (3) lowering the platform or raising the printer head by the layer thickness of the model. In the end, the non-solidified powders are removed [1,15]. Powder-bed 3D printing enables the production of concrete elements with a free-form design, without the requirement of designing supporting structures or tools [9].…”