The recent development of prototyping systems which can produce patterns for investment casting with significant time reduction from traditional techniques, has raised interest in the use of casting as a method to produce tooling for downstream prototype testing. However, the accuracy of the casting process remains a major obstacle to the use of these tools. Simultaneous development of numerical modelling techniques suggest that it will be possible to predict casting contraction and distortion. If this were possible, corrections could be made before castings are produced, resulting in time and cost savings, as well as potential improvement in the accuracy. Before these models can be applied, there is a need for both material property data and experimental data with which to validate the numerical models. The aims of this work are to: 1) Develop further understanding of the processes in investment casting that contribute to the dimensional changes and variability. 2) Develop the required data for numerical modelling and apply this to simulate the dimensional changes in investment casting. An apparatus has been designed to measure the dimensional and thermal history of investment castings with displacement transducers and thermocouples. Casting dimensions were also accurately measured to determine the final contraction of nominally unconstrained and thermally constrained castings. Numerical simulations of the temperatures, stress and distortion were compared with the experimental results and provide a detailed explanation of the processes involved. Data for these simulations were developed using a combination of direct measurement and iterative inverse modelling.
| Identifer | oai:union.ndltd.org:ADTP/253772 |
| Creators | Morwood, Gregory David |
| Source Sets | Australiasian Digital Theses Program |
| Detected Language | English |
Page generated in 0.0188 seconds