Large scale additive manufacturing of artificial stone components using binder jetting and their X-ray microtomography investigations

Abstract

Additive manufacturing of large scale parts is an innovative, challenging research field, with the potential of producing parts with complex structures, specific functional and structural properties. In this study, binder jetting was employed using two different large scale printers to fabricate non-structural parts made of artificial stone. The printing bed was comprised of aggregates (River sand and Poraver expanded glass) and reactive magnesium oxide and potassium phosphate powders, which were activated by selectively depositing water, layer after layer. The exothermic reaction between reactive powders and water generates in situ a hydraulic inorganic binder, that binds the aggregates in the bed. The reaction parameters were controlled to achieve a fast setting, enabling rapid printing at the macro-scale (in the range of tens of centimeters or meters). The influence of the voxel size of the printers on the microstructure and printing quality of the fabricated parts, their physical and mechanical properties as well as the in situ formation of the cement phase were investigated by X-ray microtomography.