Improving ceramic monolith properties in binder jetting 3D printing using glass frit binders

Abstract

In this study, a glass frit binder capable of replacing liquid binders was applied to improve the density of the object manufactured by the binder jetting 3D printing technology. To secure easy ejection from the inkjet head, the viscosity, surface tension, and stability of the glass frit binder were selected as important factors and their optimal values were determined. Of the seven dispersants tested, 0.8 mg/m2 of Na-polyacrylic acid with a molecular weight of 8100 g/mol resulted in the best dispersion characteristics. The optimal surface tension was confirmed when 1.0 wt% of polysiloxane was added. The stability of the slurry improved and the role of the binder was induced on adding 6 wt% of polyvinyl alcohol. 100×10×5 mm3 test specimens were fabricated by jetting the optimized glass frit binder to a silicate mixed powder and the density change was observed. The densities and water absorption rates of the specimens sintered at 1,200 oC, 1,250 oC, and 1,300 oC were determined. The specimens fabricated with the glass frit binder exhibited approximately 19% higher density than those fabricated with a liquid binder at all temperatures. This could be because the frits in the binder melted during the firing process and filled the pores.