Principal investigator: Bo Li, Qianhong Wu

University: Villanova University

Industry partners: The ExOne Company

The goal of this process innovation project is to support ExOne’s next generation binder jet 3D printing technology through the seamless integration of the PIs’ expertise in fluidic visualization, simulation, and material design. One of the benefits of binder jet printing is the ability to use a variety of industry standard materials, like metals, ceramics, and sands, to produce new products. This flexibility creates significant challenges—unique process settings must be developed for each material class. While powder shape, rheology, and particle size distribution can be quantified, the binder-particle interaction at the microscale has yet to be revealed. Currently, trial and error on a printer is the only way to develop process settings for a new powder.

We propose to visualize the microscale binder-particle interaction and generate guidelines for material and parameter selection of the binder jet 3D printing. While this process is understood in theory and was demonstrated in macroscale, there is limited research to visualize it in the microscale, which requires a synergistic effort from fluidics and material design. From the fluidic perspective, a high-speed camera will be used to visualize the wetting process of the porous bed of microparticles. A physics-based transport model and computational fluid dynamics simulations will be compared with the experimental results. From the material perspective, the properties of microparticles will be characterized and tailored to provide key variables to establish the model. The influence of particle size, size distribution, surface coating, and surface roughness will be studied. The surface properties of microparticles will be tailored through UV light and plasma treatment to differentiate the influence of surface properties and create new technologies to tailor the binder-particle interaction. The goal is to establish a comprehensive binder-particle interaction model to accelerate the creation of new materials and enhance the efficiency of ExOne’s 3D printing technology.