Optimization Of The Pure Titanium Denture Frameworks Casting Parameters Based On Numerical Simulation

Objective:With the help of numerical simulation technology, this study was aiming at finding out which casting parameters designs was more suitable for the casting of titanium removable partial denture(RPD) frameworks,thus optimizing and quantify the optimal casting parameters. A sound design was to be proposed for production of titanium removable partial denture frameworks to cost savings.At the same time, it would deeper discuss how numerical simulation techniques applied to the field of precision casting titanium denture frameworks.Method:A cobalt-chromium alloy RPD framework was fabricated. Geometry of the framework and sprue gate digital model was established by using 3D laser scanning technology and reverse engineering technology. Then using CAD software-UG we designed the framework entity model with the casting system. After producing tetrahedral mesh and defining simulation parameters such as the interface,initial and boundary condition for specific titanium with a casting simulation software ProCAST。Casting defects was closely related to mold temperature and casting pressure.According to the failures of machining center, we set two variable parameters,one was the mold temperature (room temperature),the other was casting pressure (0.2MPa).Then the simulation software analyzed and calculated casting process,and compared model filling and solidification process.we further modified these two parameters until a satisfactory castings could be got.Finally,mold temperature and casting pressure were determined through the actual production.Result:1.The pure titanium denture frameworks filling process was extremely short.2.Solidification process followed the principle of sequence solidification, and the gating system was the last to solidify;3.At 25°C of the model temperature and 0.2MPa of casting pressure were prone to casting defects;4. Under the same conditions of casting pressure, the higher the model temperature had, the less shrinkage appeared. Under the same conditions of model temperature, the higher the casting pressure reached, the less casting shrinkage hole grew.5.By actual casting, we set the casting ring set temperature is 150 °C and the casting pressure is 0.3MPa, which enhances the success rate of castings. Conclusion:It was feasible that numerical simulation techniques was impressed on the field of precision casting titanium denture frameworks. The casting parameters had some influence on it. At 25 ° C of the mold temperature and 0.2MPa of casting pressure were prone to casting defects.So we made a conclusion that 150℃ of mold temperature and 0.3MPa of casting pressure could be suitable for production casting of pure titanium denture frameworks.