Not only is the material strengthened by the 3D layer-by-layer printing, the binder jet printing process saves money and speeds the printing process.  

Silica sand is easily available and is inexpensive and does not change dimensions when heated, making it a strong choice for washable tooling, but current sand-casting molds have limited use because they often break. ORNL’s new PEI binder changes that situation by strengthening the molds and parts.  

“To ensure accuracy in tooling parts, you need a material that does not change shape during the process, which is why silica sand has been promising. The challenge has been to overcome structural weakness in sand parts,” said lead author of the study Dustin Gilmer, a student at the University of Tennessee Bredesen Center. “Our high-strength polymer sand composite elevates the complexity of parts that can be made with binder jetting methods, enabling more intricate geometries, and widens applications for manufacturing, tooling, and construction.”