Ti–6Al–4V alloy cortical bone screw production by powder injection molding method

In this study, Ti–6Al–4V alloy is targeted to produce cortical bone screw by powder injection molding method. The rheology study was experimentally performed with PEG8000: PP: SA binder system. Thermogravimetric (TGA) analyzes were performed for F1 feedstocks. F1 feedstock showed the ideal properties in terms of viscosity and melt flow index values. Autodesk Moldflow simulation was carried out on a screw part for moldability. In the rheology analysis, F1 feedstock exhibited superior properties with the viscosity of 72–1001 Pa · s, melt flow index of 261–1888 g/10 min and highest volume ratio of 60%. It was decided to perform the injection molding with F1 feedstock at the end of experimental and simulation studies. In this concept, rheology, molding, debinding, sintering and simulation analyses were performed. Experiments with different injections (1000 and 1200 bar) and holding pressures (400 and 600 bar), flow rate (17,260 cm³ and 20, 11 cm³) and temperatures (200 and 237 °C) were made and cortical bone screw were successfully molded. Debinding process was performed at different temperatures until 900 °C with 1 °C/min intervals. Sintering process was performed at 1250 °C and 5 °C/min heat rate. Finally, the powder injection molding parameters of the Ti–6Al–4V cortical screw bone were determined.