3D printing of hydroxyapatite: Effect of binder concentration in pre-coated particle on part strength

Pre-coating of hydroxyapatite particles with low-cost water-soluble natural polymer binder by spray drying technique was used to prepare raw material. Influence of binder concentration in the slurry for pre-coated particle on the properties of hydroxyapatite part fabricated by three-dimensional printing (3DP) was demonstrated in this study. The concentration of binder was found to influence properties of both green and sintered parts. It was observed that sintered strength of hydroxyapatite increased with increasing green strength which in turn increased with increasing the binder concentration and pre-coated particle size. From this study, it is likely that a large pre-coated particle would yield a stronger 3DP hydroxyapatite part. This is related to the better densification of intra-particles than inter-particles during sintering process.