From the development of low-cost filament to 3D printing ceramic parts obtained by fused filament fabrication

The cost of manufacturing a structural ceramic component is a direct function of production quantity. Small-quantity production, such as prototypes manufactured by conventional methods, leads to long production times and high unit costs. The advent of fused filament fabrication of ceramic (FFFC) technology has created an opportunity to reduce lead time and cost and produce complex-shaped bodies with tailored sized and controlled porosity in small-quantity production runs, which is an advantage over traditional methods of fabrication of ceramic products. In this work, we propose to study the feasibility of manufacturing a low-cost composite filament, for FFFC processing, based on micrometric alumina (Al2O3) powder and polylactic acid (PLA) polymer as a binder system without any additive. Three compositions with the ceramic-to-polymer ratios (by volume) were considered: 70% Al2O3/30% PLA, 60% Al2O3/40% PLA, and 50% Al2O3/50% PLA. For that, the customized technological chain is adapted. It consists of four principal steps: (i) grinding in a ball mill and drying the raw powders; (ii) extrusion into ceramic-polymer filament; (iii) printing of ceramic-polymer samples; and (iv) thermal debinding and sintering samples to obtain the ceramic product. The physical, microstructural, and mechanical properties of raw materials, composite filament, and green and sintering samples are investigated and the optimal composition is chosen dependent on both homogeneous repartition of the Al2O3 powder and the printability of filament. The 3D sintered material obtained by 60% Al2O3/40% PLA composite filament shows the best flexural strength value of 332 ± 21 MPa with a relative density of ~ 91%, which may be sufficient for several technical applications. Note that the 60% Al2O3/40% PLA filament composite can easily be used to print a complex geometry using a standard nozzle of 0.4 up to 0.8 and does not show signs of brittleness during the printing process allowing it to become a promising material for the FFFC process. Based on the results of this paper and previous studies, FFFC technology can be a technically feasible and economically viable process for manufacturing ceramic components under certain conditions.