Charakterisierung additiv gefertigter keramischer Bauteile via FFF-Verfahren

New Feedstock System for Fused Filament Fabrication of Sintered Alumina Parts

“…Regarding the realization of dense ceramic parts via FFF a process chain analogous to injection molding was developed. This was successfully demonstrated earlier applying a binder system consisting of wax and polyethylene [ 23 , 24 ] covering the following steps: Material (filler, binder, and surfactant) selection; Compounding and rheological characterization; Filament extrusion; Feedstock printing; and Thermal post-processing (debinding, sintering) …”

“…In the case of SLA, this technology has been commercialized (Lithoz GmbH, Vienna, Austria, ), recent research can be found in [ 17 , 18 , 19 , 20 , 21 , 22 ]. The fabrication of ceramic or metallic parts by FFF has the major advantage that experience derived from powder injection molding (PIM) helps to develop highly filled feedstocks (ceramic: >45 vol.%, metal: >60 vol.% solid load) with a similar binder composition [ 23 , 24 ]. Considering only ceramics, up to now mostly sintered alumina or mullite [ 23 , 24 , 25 , 26 ], zirconia [ 27 , 28 , 29 ], or silicon nitride [ 30 ] parts have been realized, typical binder components are paraffin wax, (modified) polyolefines, or thermoplastic elastomers.…”

“…The fabrication of ceramic or metallic parts by FFF has the major advantage that experience derived from powder injection molding (PIM) helps to develop highly filled feedstocks (ceramic: >45 vol.%, metal: >60 vol.% solid load) with a similar binder composition [ 23 , 24 ]. Considering only ceramics, up to now mostly sintered alumina or mullite [ 23 , 24 , 25 , 26 ], zirconia [ 27 , 28 , 29 ], or silicon nitride [ 30 ] parts have been realized, typical binder components are paraffin wax, (modified) polyolefines, or thermoplastic elastomers. Fatty-acid derivatives, like stearic acid, or commercial additives with proprietary composition, are widely established as surfactants or plasticizers [ 23 , 24 , 25 , 27 , 28 , 30 , 31 ].…”

“…Considering only ceramics, up to now mostly sintered alumina or mullite [ 23 , 24 , 25 , 26 ], zirconia [ 27 , 28 , 29 ], or silicon nitride [ 30 ] parts have been realized, typical binder components are paraffin wax, (modified) polyolefines, or thermoplastic elastomers. Fatty-acid derivatives, like stearic acid, or commercial additives with proprietary composition, are widely established as surfactants or plasticizers [ 23 , 24 , 25 , 27 , 28 , 30 , 31 ]. Like feedstocks in ceramic injection molding, two component binder mixtures are often applied, one low molecular mass material allows a low melt viscosity at moderate temperatures and one high molecular mass fraction (backbone polymer) delivers a certain mechanical stability at lower temperatures after shaping.…”

“…Like feedstocks in ceramic injection molding, two component binder mixtures are often applied, one low molecular mass material allows a low melt viscosity at moderate temperatures and one high molecular mass fraction (backbone polymer) delivers a certain mechanical stability at lower temperatures after shaping. The low molecular mass compound can be removed during an organic solvent pre-debinding step after printing, e.g., in hexane [ 23 , 24 ] or cyclohexane [ 28 ]. In micro ceramic injection molding, new binder systems avoiding the necessity to use organic solvents for pre-debinding have been developed.…”