Finite Element Analysis and Strain Gauging of the Stereolithography/Investment Casting System

Many metal parts have been produced from stereolithography (SL) models via the investment casting route. However, it is still not possible for every foundry to directly use SL models as thermally expendable patterns and gain the same success as achieved with wax patterns. Significant drawbacks still exist with the QuickCastTM structure that restricts its use to specialist investment casting foundries who are willing to alter their standard techniques. As part of a continuing work programme at the University ofNottingham, the stresses that are created in the SL/ceramic construction have been determined using simple stress analysis and finite element analysis techniques. Further work has involved connecting strain gauges and thermocouples to SL parts in order to confirm the results obtained with the theoretical stress analysis. Inspection of the results obtained is aiding the generation of new build structures to enable the successful autoclaving of SL models. Details ofthe work to date are outlined in this paper, along with the results obtained.