Minimizing Core Displacement in Cast Pattern of Turbine Blade via Fixture Layout Optimization

Core displacement during wax injection significantly undermines the dimensional accuracy of wall thickness in investment-cast turbine blades, presenting an ongoing challenge in high-precision blade manufacturing. To solve this problem, this study proposes an integrated optimization strategy for the fixture layout within the wax pattern die, aiming to enhancing the positional accuracy of the ceramic core in cast patterns. First, three distinct fixture layout models in wax pattern die are developed to mitigate positional errors of ceramic core arising from geometric inaccuracies in locators, locating instability, and insufficient fixture immobility. Subsequently, an analytical model is established to estimate the contact pressures exerted by fixture elements on the core during wax injection. Then, by coupling these models into a dual-objective optimization framework, a comprehensive fixture layout optimization method capable of simultaneously resolving multiple core-securing challenges is formulated. Wax injection simulations, supported by experimental evaluations, demonstrate that the optimized layout not only minimizes core displacement and restrains the wall thickness deviation of the wax pattern to -0.098 mm, but also prevents core cracking induced by excessive fixture compression during wax injection. The proposed framework provides a unified approach to fixture optimization under coupled fluid–structure interaction conditions and offers a generalizable methodology for improving fixture reliability in precision casting processes.