Wall thickness monitoring method for wax pattern of hollow turbine blade

The wall thickness of hollow turbine blade has emerged as a significant cause of blade retirement. The precision of the final wall thickness of blade is mainly inherited from its corresponding wax pattern. The layout scheme of ceramic locators has a great influence on the wall thickness of wax pattern. A good layout of ceramic locators can significantly reduce the wall thickness shifting. To address this issue, a stable locator layout is needed to reduce the error transferring. The main purpose of this study is to find an optimal localization scheme for ceramic core. Firstly, the mathematical model of ceramic core localization was built based on the fixture design theory. Then, the optimal algorithm of locator layout design was studied. The D-optimality criterion has been chosen as optimal design criterion. Finally, two demonstration cases were presented. A localization scheme for real ceramic core was achieved and verified by using Monte-Carlo method. Moreover, the localization scheme was validated through experiments. Both simulation and experimental results indicated that the optimal localization can significantly reduce the input error.