It is difficult to design and machine the investment casting mould for the forth-level large turbine blade of a heavy gas-turbine due to its complicated structure and large dimension as well as high accuracy requirement.Design and machining of the mould were described

in which the loop dimension is ensured by adopting segmentation treatment for blade body

and fabrication hole is used to localize the mould machining during installation manufacturing

and self-locking clamping unites are adopted to ensure the stability of working time of the mould.