基于逆向工程技术的涡轮叶片型面精铸位移场测评

Estimation of Displacement Field for Turbine Blade Profile Based on Reverse Engineering in Investment Casting

针对涡轮叶片型面精铸位移场测量评估问题,提出一种基于逆向工程的评测方法。通过三坐标测量机对实际铸件进行测量重构出型面,采用两步配准算法计算出测量模型与CAD模型的空间变换矩阵并将测量模型进行坐标变换,然后计算出测量模型各节点相对于CAD模型的法向偏移距离作为该节点的位移量并可用于后续模具的精确修正。该方法实现了对涡轮叶片型面精铸变形量的精确评测,为模具的精确修模提供了良好的技术支持。

An estimation algorithm was proposed to calculate the displacement field of turbine blade profile during solidification based on reverse engineering in investment casting. Firstly, the turbine blade profile was reconstructed based on measured data from coordinate measuring machine (CMM). Secondly, two-step match algorithm was employed to calculate the rotating and translating matrixes which were defined as the best space transformation of reconstructed profile to CAD model profile. Thirdly, the normal offset-distance of every node between the reconstructed profile and CAD model profile was calculated to be suggested as displacement of the node, which can be used for accurate modification of sequent mould. The practical validation shows that the method mentioned can achieve the accurate estimation for displacement of turbine blade profile in investment casting, providing a desirable basis for mould modification.