Investigation into 3D printing of granular media

Abstract

Advances in additive manufacturing have recently motivated interest into 3D printing of geomaterials for an array of applications within geotechnical research. However, certain obstacles exist, which are investigated in this paper. Firstly, the geometry of the proposed particles has to be chosen, so that it is representative of an actual geomaterial. Here, Hostun sand was chosen as a reference material. It was found that CT scanning, microscopy, and morphology analysis were useful tools in assessing whether the proposed medium was representative of the reference material. Secondly, a specific 3D printing technology has to be chosen. Amongst the commercially available technologies investigated, PolyJet was found to be the most appropriate for the creation of small particles. Available materials, printing resolution, and support material removal were considered. Support material removal was found to be a limiting factor as very small particles can delaminate during this process. As a result, a particle diameter of 2 mm is proposed as the lower limit that can be reliably reproduced with the current level of PolyJet 3D printing.