Fused Deposition Modeling

Figure 1: Schematic process of FDM/FFF printing process. A thermoplastic filament is feed into the extrusion head by feeding rollers (a). The polymer is melted and extruded trough a nozzle (b). The extruded filament is deposited on the substrate and filament of subsequent layer is fused with the previous (c).

FDM/FFF can be used for printing ceramic materials too. Therefore, a thermoplastic is filled with a high amount of ceramic powder. This so called feedstock is shaped into a filament with constant diameter (typically 1.75 or 2.8 mm). After printing process (Figure 1), the printed parts consisting of sacrificial polymers is burned out and ceramic powder is later sintered into a dense ceramic. In principal

FDM/FFF is a thermoplastic ceramic shaping technique (Figure 2) and therefore potential polymers are similar to those used for thermoplastic pressing, extrusion and injection molding.

Figure 2: Overview of different thermoplastic shaping processing techniques for ceramic materials.

In comparison to polymeric materials, shaping of ceramic is more challenging because of high solids loading of solid ceramic particles inside the thermoplastic. It is essential to control the rheological properties of polymer - ceramic powder compounds and the effect of organic additives on the printing and debinding processing step [2-8].

There are many challenges during the production, which depend on filament properties and processing parameters (Figure 3).   

Figure 3: Different challenges in FDM/FFF technology for ceramics.

Fused deposition modelling (FDM) or fused filament fabrication (FFF) was successfully used for fabrication of various ceramic materials like lead zirconate titanate (PZT), tricalcium phosphate (TCP), alumina and mullite [1-9]. Rheological properties have significant influence on the shaping (e.g. 3D printing) process. Typically, formation of defects during shaping and further processing could be detected. By selecting the right type of thermoplastic binder, the amount of solids content and surfactant, different filaments have been developed which can be printed by the FDM/FFF technology [1-9].

Figure 4 shows different kind of ceramic materials which have been printed at Empa so far.

Figure 4: Different kind of ceramic materials printed by FDM/FFF process at Empa.

References

[1]        L. Gorjan, L. Reiff, A. Liersch, F. Clemens, Ethylene vinyl acetate as a binder for additive manufacturing of tricalcium phosphate bio-ceramics, Ceram. Int. (2018). doi:10.1016/j.ceramint.2018.05.260.

[2]        Bach M., Sebastian T., Melnykowycz M., Lusiola T., Scharf D., Clemens F. Additive Manufacturing of Piezoelectric 3-3 Composite Structures. In: Meboldt M., Klahn C. (eds) Industrializing Additive Manufacturing - Proceedings of Additive Manufacturing in Products and Applications - AMPA2017. AMPA 2017. Springer, Cham, ISBN 978-3-319-66865-9 (2018): 93-103.           

[3]        Gonzalez-Gutierrez, J., Cano, S., Schuschnigg, S., Kukla, C., Sapkota, J., Holzer, C., Additive manufacturing of metallic and ceramic components by the material extrusion of highly-filled polymers: A review and future perspectives. Materials 5 (2018), 840. doi:10.3390/ma11050840.

[4]        Nötzel, D., Eickhoff, R., Hanemann, T. Fused filament fabrication of small ceramic components. Materials 11(2018),1463. https://doi.org/10.3390/ma11081463

[5]        Cano, S., Gonzalez-Gutierrez, Sapkota, J., Spoerk, M., Arbeiter, F., J., Schuschnigg, S., Holzer, C., S., Kukla, Additive manufacturing of zirconia parts by fused filament fabrication and solvent debinding: Selection of binder formulation. Additive Manufacturing 26 (2019), 117-128. doi:10.1016/j.addma.2019.01.001.

[6]        T.F. McNulty, F. Mohammadi, A. Bandyopadhyay, D.J. Shanefield, S.C. Danforth, A. Safari, Development of a binder formulation for fused deposition of ceramics. Rapid Prototyping Journal, 4 (1998), 144-150. https://doi.org/10.1108/13552549810239012

[7]        M.A. Jafari, W. Han, F. Mohammadi, A. Safari, S.C. Danforth, N. Langrana, A novel system for fused deposition of advanced multiple ceramics. Rapid Prototyping Journal, 6 (2000), 161-175. https://doi.org/10.1108/13552540010337047https://doi.org/10.1108/13552540010337047

[8]        R. Atisivan, S. Bose, A. Bandyopadhyay, Porous mullite preforms via fused deposition. J. Am. Ceram. Soc., 84 (2001), 221-223. https://doi.org/10.1111/j.1151-2916.2001.tb00635.x

[9]   L. Gorjan, R. Tonello, T. Sebastian, P. Colombo, F. Clemens Fused deposition modeling of mullite structures from a preceramic polymer and γ-alumina. J. European Ceramic Society (2019), online.   https://doi.org/10.1016/j.jeurceramsoc.2019.02.032