CAREER: Powder Preparation and Compaction for Ceramic Binder Jet Additive Manufacturing

This Faculty Early Career Development (CAREER) grant supports fundamental research that will generate knowledge related to ceramic binder jet additive manufacturing, promoting the progress of science and resulting in beneficial societal impacts. Advanced ceramic materials play a vital role in numerous applications with strict requirements or under harsh conditions, such as those in the biomedical, aerospace, chemical, and energy industries. Traditional manufacturing methods for ceramic parts have severe geometric constraints, long production time, and high cost. Binder jet additive manufacturing can overcome these drawbacks. However, it is currently unable to produce dense ceramic parts, significantly limiting its applications. This research aims to increase understanding of how powder granule characteristics (density, structure, and strength) and powder compaction affect resulting part density. In addition, this CAREER plan includes a series of education activities to strengthen and diversify the advanced manufacturing workforce, impacting K-12 teachers and students, undergraduate and graduate students, and professionals in the industry. The goal of this research is to enable a new density improvement approach for ceramic binder jet additive manufacturing, using a tailored feedstock powder and an emerging powder bed formation method. The feedstock powder consists of granules composed of numerous nanoparticles that are weakly bonded together. In the powder bed formation method, compaction is performed after spreading each layer of powder. It is hypothesized that the required compaction pressure to achieve dense ceramic parts is affected by granule characteristics in the following manners: (1) granules with a low density require a lower pressure to fracture or plastically deform (a positive effect), but have a lower initial packing density (a negative effect); (2) granules with a porous structure can be more easily fractured or plastically deformed, but have more initial intragranular pores; (3) granules with a low strength can also be more easily fractured or deformed, but have a reduced initial granule rearrangement. Experimental research will be conducted to identify the tradeoffs associated with each granule characteristic and to determine the conditions under which its positive or negative effect is dominant. Afterward, numerical simulation at the granule and nanoparticle scales will be performed to explain the experimental results and to provide physical insights on underlying compaction mechanisms. This research will generate new knowledge about compaction of multiple thin layers of granules that is critical to binder jet additive manufacturing. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.