| Investment casting process, or the lost wax process, is a manufacturing method for alloy-based parts of many industrial and commercial applications. It offers a high degree of precision in regard to dimensions as well as excellent surface finishes. The process gets more complicated and prone to defects when bi-metals are involved. Since it is relatively complex and expensive compared with other casting processes (e.g., sand, permanent mold, etc.), total reliance on the old-fashioned trial-and-error approach to selecting various process parameters is generally found to be tedious, time-consuming, expensive and inadequate. In recent years computer simulation of the process has begun to complement the experience-based approach in meeting the demands of high quality investment cast parts in a cost-effective manner. This dissertation presents an integrated technology of optimizing investment bi-metal casting process and every closely related subjects, such as empirical design rules, CAD/CAE software and finite element method process simulation. The current state of technical affairs relating to CAD/CAE software, finite element algorithms, defect analysis and empirical rules of investment bi-metal casting process is reviewed, considering theoretical as well as application oriented aspects. As a case study, by employing the integrated optimization technology, an investment bi-metal casting process of Spiral Flight is optimized to obtain better process specifications that can eliminate or greatly reduce the existing defects. The dissertation ends with a discussion of future trends in optimization technology of investment bi-metal casting process. |
