Tuning the rheological properties of paraffin-wax ceramic feedstocks for deposition with thermoplastic 3D printing

Droplet deposition with material-jetting methods such as thermoplastic 3D printing (T3DP) depends greatly on the rheological properties of the feedstocks. This study investigated the effect of particle interactions and the degree of weak flocculation on the shear thinning behaviour, the yield stress and the storage/loss moduli of paraffin-wax-based feedstocks containing 40 vol% of zirconia (3Y-TZP) micron-sized powder. Steric stabilization of the feedstocks was provided by varying the ratios of the surfactants with different chain lengths, i.e., stearic acid (2.4 nm) and Solsperse 3000 (R) (10 nm), which in turn affected the dynamics of the droplet formation and the quality of the layers when jetting non-Newtonian, thermoplastic ceramic feedstocks. The results of the study extend the guidelines for the processing of printable feedstocks used in T3DP additive manufacturing.