Multi-Area Vibration Precision Laying Process in Multi-Material 3D Sand Printing

Multi-material 3D sand printing has gained significant attention; however, research has mainly focused on materials and mechanisms, with limited exploration of optimizing the sand-laying process through numerical simulations. In this study, we investigated the dynamic behavior of sand particles during a vibratory sand-laying process for multi-material additive manufacturing using discrete element simulations. The objective is to enable precise control over the amount and distribution of sand for multi-material printing. In this study, we combined experiments and simulations to calibrate the contact parameters of different sands and establish a relationship between the curing agent content and surface energy of sand particles. A model for the vibratory fall of multi-material sand was developed to study the motion characteristics of sand particles. This allows for macro-control over the sand spreading flow and high-quality multi-material sand laying. The results show that the flow rate of falling sand increases with decreasing surface energy of the particles, wider spreader openings, and higher vibration frequencies. For silica and chromite sands, when their surface energy ranged from 0.15–25 J·m² and 0.01–0.03 J·m², respectively, and the sand spreader opening was 6 mm with a vibration frequency of 500 Hz, the sand flow rates of both materials became nearly identical. However, a higher sand paving speed and height increased the scattering of sand particles outside the target area, thereby decreasing the paving quality. The results accomplished in this study enable precise and uniform sand particle deposition and offers guidelines for optimizing sand speed and height, thus expanding the application of multi-material sand 3D printing in complex and high-performance manufacturing.