Numerical simulation of binder curing on the penetration in sand bed

Abstract

In sand mold three-dimensional printing (3DP), penetration of the binder material in the sand bed is a major factor that determines the printing accuracy, but this procedure has not been studied in detail before. This study aims to fill such a gap. In this study, discrete element software EDEM was used to simulate the multilayer sanding process, and a nonuniform sand bed model was constructed. The level set method was applied to track the binder-air interface. Change in the curing state of the binder was characterized by setting different values for the dynamic viscosity of the binder liquid. The multiphysics software COMSOL was used to analyze the seepage flow of the binder in the sand bed. Results showed that the contact angle directly affected the infiltration process of the binder. The smaller the contact angle, the better the penetration effect of the binder. When selecting the binder material, it was desirable to choose a material with a smaller contact angle. Simulation study suggested that when the printing width was 1500 [Formula: see text]m, the layer thickness was 300 [Formula: see text]m, and the binder ejection volume was 200%, the printing quality was optimal among the various cases studied. The adopted technique for modeling the curing state of the binder using varying dynamic viscosity of the binder liquid was proved to work effectively and efficiently, and satisfactorily described the penetration flow of the binder during the molding process.