Improving 3D binder jet printed tungsten-carbide parts via strategies to increase green density strength

Principal investigator: Markus Chmielus

University: University of Pittsburgh

Industry partners: General Carbide

The tungsten carbide industry produces parts used in many high demand applications, including tooling for wear, as well as finishing parts and metal forming. The traditional powder forming processes that are used in the industry are limited in their ability to produce highly complex parts. To circumvent drawbacks to traditional subtractive manufacturing, additive manufacturing (AM) methods have been increasingly adopted into other industries, making the production of highly complex metal parts a possibility. Laser-based AM methods are commonly used but can be problematic because of large thermal gradients associated with repeated rapid heating and cooling. High thermal gradients are especially detrimental to tungsten carbide, causing cracking and premature failure. As a result, it is crucial to investigate a different AM method for producing highly complex tungsten carbide parts. Binder jet 3D printing (BJ3DP) is a non-laser-based method of AM that uses a binder to selectively join powder layer-by-layer, creating parts that are then pressure-sintered to achieve full density, eliminating heat-induced cracking. The previous study has exposed additional challenges, such as a need to tailor the powder before printing, and to develop process and binder modifications to increase the density of the printed parts prior to sintering. The proposed project of General Carbide Corporation and the Chmielus’s group at the University of Pittsburgh will address challenges associated with achieving high density parts to meet the mechanical property and shape change requirements of General Carbide. Success of this project will increase the competitive edge of General Carbide over international competitors and increase their capabilities to produce highly complex parts and low-count batches of parts. This project also allows for two female students to perform fundamental and applied research while directly engaging with a local PA company.