Additive manufacturing of cellular structures from recycled soda-lime glass printing inks by robocasting

The robocasting technique has shown great potential due to its versatility, allowing the fabrication of custom -shaped, dense or porous structures, through layer-by-layer deposition. The technical feasibility of robocasting depends on rigorous control of the rheological properties of printing inks, which needs to have fluidity for pumping and plasticity for extrusion/printing, while being able to withstand the weight of overlapping layers. The aim of this work is to produce cellular glass structures by direct printing (robocasting) using bentonite to overcome the lack of plasticity of glass powders. Ceramic inks containing recycled glass powders (d(50) < 4 mu m) and bentonite (6.5-9.5 wt%) were blended and printed using a 1.60 mm printing nozzle at a printing speed of 10 mm/s. The three-dimensional structures were dried at room temperature for 24 h and then fired at 700 degrees C for 1 h at a heating rate of 10 degrees C/min. The components obtained from recycled glass showed porosities of up to 53%, pore sizes between 1090 and 1870 mu m and compressive strength of similar to 18 MPa.