Effect of mixing parameters on the mixing time and density of composite HA/Ti6Al4V feedstock for powder injection molding

Abstract

Hydroxyapatite is a bioactive material. However, Hydroxyapatite in medical application is limited by its poor mechanical properties. Titanium alloys are biocompatible materials with high specific strength and high corrosion resistance. This combination can successfully be used in biomedical applications. The mixing process is a critical stage in the metal injection molding process because it determines the quality of the metal injection product. The homogeneity of the feedstock depends on the mixing parameters used during the mixing process. An experiment was conducted using Ti6Al4V and hydroxyapatite powder as feedstock at a mixing ratio of 60:40 wt%. This feedstock was mixed with a mixture of polyethylene and palm stearin as the binder. The mixing parameters used in this study were the mixing speed (10 and 30 rpm) and the mixing temperature (130°C and 150°C) at a powder loading of 67%, as determined by the critical powder volume percentage experiment data (69.5%). Increases in the mixing speed and mixing temperature reduced the mixing time to achieve homogeneity. The combined feedstock achieved the highest density at a mixing speed of 30 rpm and a mixing temperature of 150°C.