Core shifting prediction in filling process of hollow turbine blade investment casting

Abstract

Ceramic core shifting during the filling process of investment casting is one of the key factors that influence the wall thickness accuracy of hollow turbine blades. Although plenty of study has conducted to analyze and control the wall thickness accuracy, the mechanism of core shifting has rarely taken much attention. To fill this gap, this paper firstly analyze the movement of ceramic core under the casting condition combining computational fluid dynamics and motion simulation. Then, the shifting mode and final position of ceramic core were predicted based on the time-varying load in investment casting filling process. Afterwards, a casting experiment was conducted to verify the proposed prediction method and the results show a good match. In addition, a wax pattern reverse compensating approach was devised and validated based on the prediction result. After correction, the maximum displacement of the ceramic core has lowered by 51.6 %, indicating that the suggested approach is successful in improving the wall thickness accuracy.