A Versatile Thermally Initiated Crosslinking Binder for Additive Manufacturing of Strong Structures

Binder jetting additive manufacturing (BJAM) is one of the most promising additive manufacturing (AM) techniques for industrial manufacturing due to its high productivity, wide material compatibility, and the possibility to achieve large-scale production. BJAM utilizes binder jetting to selectively bind powdered materials into complex three-dimensional (3D) objects. However, the inability of conventional binders to create high-strength green parts has become a major limitation for BJAM. Here, we report on a versatile thermally initiated crosslinking (TIC) binder to overcome the low green strength issue; the binder is composed of an initiator ink and an in-bed monomer/crosslinker mixture. The TIC binder can form a continuous, uniform, and strong crosslinked network to pack the printed powder. A flexural strength of 10.1-13.9 MPa of green parts is achieved for several powders, including SiC, Al2O3 , and 316 L stainless steel, using the developed TIC binder. The TIC binder also shows a high print reliability and a good robustness for complex and fine geometric structures. These features combined with the advantages of a low cost, ultrahigh curing speed, and reasonable burnout performance indicate that the TIC binder solution has the potential to make a large impact on the BJAM progress.