Wu M, Augthun M, Schädlich-Stubenrauch J, Sahm P R, Spiekermann H
Foundry Institute, University of Technology Aachen, Germany.
Eur J Oral Sci. 1999 Aug;107(4):307-15. doi: 10.1046/j.0909-8836.1999.eos107411.x.
The objective of this research was to analyse, predict and control the porosity in titanium dental castings by the use of numerical simulation. A commercial software package (MAGMASOFT) was used. In the first part of the study, a model casting (two simplified tooth crowns connected by a connector bar) was simulated to analyse shrinkage porosity. Secondly, gas pores were numerically examined by means of a ball specimen with a "snake" sprue. The numerical simulation results were compared with the experimental casting results, which were made on a centrifugal casting machine. The predicted shrinkage levels coincided well with the experimentally determined levels. Based on the above numerical analyses, an optimised running and gating system design for the crown model was proposed. The numerical filling and solidification results of the ball specimen showed that this simulation model could be helpful for the explanation of the experimentally indicated gas pores. It was concluded that shrinkage porosity in titanium dental casting was predictable, and it could be minimised by improving the running and gating system design. Entrapped gas pores can be explained from the simulation results of the mould filling and solidification.
本研究的目的是通过数值模拟来分析、预测和控制钛牙科铸件中的孔隙率。使用了一个商业软件包（MAGMASOFT）。在研究的第一部分，对一个模型铸件（由连接杆连接的两个简化牙冠）进行模拟，以分析缩松。其次，通过带有“蛇形”浇道的球形试样对气孔进行了数值研究。将数值模拟结果与在离心铸造机上制作的实验铸造结果进行了比较。预测的收缩水平与实验确定的水平吻合良好。基于上述数值分析，提出了牙冠模型的优化浇注和浇口系统设计。球形试样的数值充型和凝固结果表明，该模拟模型有助于解释实验显示的气孔。得出的结论是，钛牙科铸件中的缩松是可预测的，并且可以通过改进浇注和浇口系统设计将其降至最低。从充型和凝固的模拟结果可以解释截留气孔的问题。
