A systematic characterisation of bone tissue scaffolds fabricated via 3D 
printing from hydroxyapatite (HA) and poly(vinyl)alcohol (PVOH) composite 
powders is presented. Flowability of HA:PVOH precursor materials was observed to 
affect mechanical stability, microstructure and porosity of 3D printed 
scaffolds. Anisotropic behaviour of constructs and part failure at the 
boundaries of interlayer bonds was highlighted by compressive strength testing. 
A trade-off between the ability to facilitate removal of PVOH thermal 
degradation products during sintering and the compressive strength of green 
parts was revealed. The ultimate compressive strength of 55% porous green 
scaffolds printed along the Y-axis and dried in a vacuum oven for 6h was 0.88 ± 
0.02 MPa. Critically, the pores of 3D printed constructs could be user designed, 
ensuring bulk interconnectivity, and the imperfect packing of powder particles 
created an inherent surface roughness and non-designed porosity within the 
scaffold. These features are considered promising since they are known to 
facilitate osteoconduction and osteointegration in-vivo. Characterisation 
techniques utilised in this study include two funnel flow tests, scanning 
electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), 
compressive strength testing and computed tomography (CT).