Ceramic fused filament fabrication (CF$^3$) of zirconia implants by using flexible, partially water-soluble binder systems

Ceramic Fused Filament Fabrication offers a simple and cost-effective method to manufacture personalized ceramic implants. However, the lack of flexibility in highly filled filaments and the reduced accuracy compared to alternative additive manufacturing techniques limit the method’s widespread implementation. Therefore, an eco-friendly partially water-soluble binder system containing polyethylene glycol (PEG), poly(vinylbutyral) (PVB), and poly(methylmethacrylat) (PMMA) was investigated, along with the influence of the two additives acetyltributylcitrate (ATBC) and lauric acid (LA). The created feedstocks were characterized by comprehensive rheological analysis, which included capillary rheology and dynamic mechanical analysis. The production of filaments with a solid content of 50 vol% was successfully achieved, demonstrating exceptional flexibility and flow properties. Following the debinding and sintering processes, the optimal feedstock systems enabled the fabrication of defect-free components with a high level of detail and relative densities up to 100 %.