Additive manufacturing of dense zirconia ceramics by fused deposition modeling via screw extrusion

A fused deposition modeling(FDM)system via screw extrusion suitable for feeding granular feedstocks with high solid loading was developed. Key parameters included aspect ratio of the screw, the compression ratio and pitch etc. In order to get constant extruded mass flow and wire diameter a processing window was determined by optimizing the barrel temperature, the nozzle diameter and the screwing speed. Microstructural characterization coupled with flexural strength measurement revealed that a higher printing temperature was beneficial to the inter layer bonding. The sintered zirconia ceramic samples with 99% of theoretical density of the 3 mol% yttria stabilized tetragonal zirconia polycrystal (3Y-TZP) and flexural strength of 890 +/- 60 MPa was obtained. A set of zirconia ceramic parts with complex geometries and controllable dimensional accuracy was also successfully prepared for demonstrating the potential of the technique.