Effect of the Properties of Binder and Powder Used in Binder Jet 3D Printing on Build-Up

The binder jetting method wherein a liquid adhesive is sprayed and built up on a powder material, such as sand, is relatively fast among 3D printing technologies, and it has a wide range of applications due to the flexibility to use various materials in powdered form. In this study, to secure jetting stability when synthesizing a silicate (SiO2-Na2O)-based inorganic binder for binder jetting, the optimum physical properties of the inorganic binder were confirmed by controlling the viscosity and surface tension. In addition, the strength of the printed mold body, which changes according to the properties of the powder used for printing, was confirmed. As a result, the inorganic binder for 3D printing had a surface tension between 45.9 and 47.1 mN/m, and the binder with a Z value between 9.45 and 9.98 formed stable droplets. In addition, the more hydrophilic the surface of the powder used for 3D printing, the higher the affinity between the surface and the inorganic binder, which increases the wettability, thus enhancing the printing quality. However, we confirmed the final strength of the product decreased because the binder bridge was short owing to the low contact angle.

Automated summary

In this study, the optimal physical properties of an inorganic binder for binder jetting were determined by controlling the viscosity and surface tension. The strength of the printed mold body, which is influenced by the properties of the powder used, was also confirmed. The results showed that the inorganic binder with a surface tension between 45.9 and 47.1 mN/m and a binder with a Z value between 9.45 and 9.98 formed stable droplets. Furthermore, the hydrophilicity of the powder used for 3D printing was found to enhance the printing quality by increasing the affinity and wettability of the binder, but it decreased the final strength of the product due to the shorter binder bridge caused by the low contact angle.