3D printing technique of specific bone shape based on raw clay using hydroxyapatite as an additive material

Abstract In recent years, 3D printing technique has been used to produce bone implants that mimic the properties and functions of bone for virtualized operative planning. Although hydroxyapatite has been used as a precursor for scaffold production, the hydroxyapatite-based specific bone production of the patient has few successes. This research developed specific bone production by 3D printing using raw clay and hydroxyapatite as an additive. The flow rate of extrusion of raw clay and hydroxyapatite composite for producing rectangular samples was studied. It was found that the suitable flow rate was 9.0 mm3/s and it was used to print rectangular samples with various ratios of raw clay and hydroxyapatite from 95:5 to 75:25 wt%. The results showed that 95:5 to 80:20 wt% ratios of raw clay and hydroxyapatite indicated significantly printing quality. The rectangular samples of different ratios were further investigated on their volume shrinkage, bending strength, and phase transformation after the sintering process. The maximum bending strength and volume shrinkage of 80:20 wt% ratio of raw clay and hydroxyapatite were 88.72 MPa and 40.41%, respectively. Finally, the dog bone radius production demonstrated the printability of a suitable ratio between raw clay and hydroxyapatite. Moreover, the hydroxyapatite containing raw clay cloud be used as the material to successfully produce a specific dog bone and other complex shapes using 3D printing.