Abstract
An important factor in determining tooling allowances in investment casting is the dimensional change of the wax pattern. Dimensional changes between a pattern die and its wax pattern occur as a result of complex phenomena such as thermal expansion-contraction and hot deformation (elastic, plastic, and creep). Thus, the wax pattern dimensions are determined by the wax's thermophysical and thermomechanical properties, restraint of geometrical features by the metal die, and process parameters such as die temperature, platen temperature, injection pressure, injection temperature, and dwell time. In this paper, constitutive equations of material behavior that determine dimensional changes associated with the wax system are provided. Material property measurements were conducted in this study for Cerita™ 29-51 wax with the aim of obtaining a complete set of data that can be used as input in computer simulation software for predicting wax pattern dimensions.
| Original language | English |
|---|---|
| Pages (from-to) | 125-134 |
| Number of pages | 10 |
| Journal | Materials Science and Engineering: A |
| Volume | 362 |
| Issue number | 1-2 |
| DOIs | |
| State | Published - Dec 5 2003 |
Funding
This work was performed for the project on Predicting Pattern Tooling and Casting Dimensions for Investment Casting, conducted in collaboration with the 4L Investment Casting Committee of the American Foundry Society and the Cast Metals Coalition. The research was sponsored by the US Department of Energy, Office of Energy Efficiency and Renewable Energy, Metal Casting Industries of the Future, under contract DE-AC05-00OR22725 with UT-Battelle, LLC. The authors would like to thank M. Argueso & Co., Inc., for providing the wax for this study, Dr. R.S. Rounds of Fluid Dynamics, Inc., Dr. J.H. Suwardie of Rheometric Scientific, and Dr. G.M. Rowe of Abatech, Inc., for conducting shear rheometry experiments using melt rheometers, ARES, and BBR, respectively, H. Lobo and T. Bethard of Datapoint Labs, Inc., for conducting DSC, PVT and thermal conductivity measurements, Dr. H.H. Winter of University of Massachusetts at Amherst for determining the discrete relaxation spectra for the ARES data, Dr. G.M. Rowe of Abatech, Inc., for determining the discrete relaxation spectra for the combined set of data ARES and BBR. The authors would also like to thank G.R. Romanoski and N.C. Gallego for reviewing the paper.
Keywords
- Dimensions
- Distortion
- Investment casting
- Paste
- Rheology
- Shear modulus
- Shift factor
- Viscoelastic
- Wax