Preparation and characterization of starch-based binders for binder jetting

In recent years, binder jetting technology has made significant advances across industries, expanding the range of material options to meet diverse needs. Commonly used binders may leave residues during the sintering process, affecting surface quality and performance, and some may contain harmful substances. Therefore, there is a high demand for binders that are environmentally friendly and easy to remove. This study proposes to use sodium alginate and polyvinylpyrrolidone as additives to prepare starch-based inks that are both environmentally friendly and safe. The effects of additive composition, starch content, dispersant content, and dispersant ratio on the viscosity and stability of starch-based inks were studied. Through performance testing, the particle size, surface tension, rheological properties, and printability of inks with different components were demonstrated. The optimal ink formulation consists of 1 wt% starch and 0.3 wt% additives (30 wt% sodium alginate and 70 wt% PVP). The viscosity reaches 23 mPa s and the stability is excellent. The surface tension of the ink is 69.5 mN m^-1, which is slightly higher than the surface tension requirements for the printhead. This article provides a new process route for binder jetting technology and lays the foundation for its application in green and environmental protection.