Numerical simulation of porosity-free titanium dental castings

The objective of this research was to analyse, predict and control the poro sity in titanium dental castings lay the use of numerical simulation. A com mercial software package (MAGMASOFT) was used. In the first part of the stu dy, a model casting (two simplified tooth crowns connected by a connector b ar) was simulated to analyse shrinkage porosity. Secondly, gas pores were n umerically examined by means of a ball specimen with a "snake" sprue. The n umerical simulation results were compared with the experimental casting res ults, which were made on a centrifugal casting machine. The predicted shrin kage levels coincided well with the experimentally determined levels. Based on the above numerical analyses, an optimised running and gating system de sign for the crown model was proposed. The numerical filling and solidifica tion results of the ball specimen showed that this simulation model could b e helpful for the explanation of the experimentally indicated gas pores. It was concluded that shrinkage porosity in titanium dental casting was predi ctable, and it could be minimised by improving the running and gating syste m design. Entrapped gas pores can be explained from the simulation results of the mould filling and solidification.