The role of paraffin wax on the properties and printability of ethylene vinyl acetate-based feedstocks for alumina fused filament fabrication

Fused filament fabrication (FFF) is a versatile and inexpensive additive manufacturing (AM) technique for fabrication of complex shaped ceramic structures. The composition of the binder phase in ceramic-filled feedstock is crucial in determining its rheological behaviour during processing as well as the ability to obtain a defect-free part following debinding and sintering. In this study, the effect of paraffin wax (PW) addition to alumina feedstock with ethylene vinyl acetate (EVA) binder, on feedstock preparation, printability, and debinding has been investigated. The PW incorporation resulted in successful fabrication of a flexible filament with a bending (fracture) strain of 4±1 %. The addition of PW however did not have a significant impact on the debinding of the developed alumina filaments. The printed parts could only be successfully debinded up to 2 mm wall thickness. The subsequent sintering of the debinded parts resulted in a relative density of 98 %. [Display omitted]