Have Researchers Found Way to Make Stronger Sand Parts Using Binder Jetting?

Researchers from the Department of Energy’s Oak Ridge National Laboratory have created a new polymer that can be used to bind and strengthen silica sand for binder jetting. In their study, “Additive manufacturing of strong silica sand structures enabled by polyethyleneimine binder,” by Gilmer et al., they found that thanks to this new binder, sand structures could be created that were significantly stronger than counterparts made with conventional binders, with one object holding 300 times its own weight. Indeed, the created binder was able to double the strength of parts.

This is one of many additive manufacturing projects that have come from the ORNL this year. Already, we have seen 3D printed fuel assembled brackers which were installed in a Nuclear Powder plant in Alabama as well as tests with ExOne, a leader in binder jetting technology, to create ceramic-metallic parts. This latest project continues to push the limits of binder jetting technology, though now in respect to sand.

Tomonori Saito shows a 3D-printed sandcastle at the DOE Manufacturing Demonstration Facility at ORNL (photo credits: Carlos Jones/ORNL, U.S. Dept. of Energy)

A Stronger Sand for Binder Jetting

Though sand is a common material for binder jetting, it is not often used for end-use parts, with certain exceptions. In the study, the researchers point notably to the inability to form strong green parts, or the parts made before debinding and sintering, with conventional binders. The discovery of the polyethyleneimine (PEI) binder for silica sand could thus help to increase usage of binder jetting in more load-bearing parts. This is also important as binder jetting has increased in popularity as it is both cheaper and faster than many other 3D printing methods.