An investigation on adaptively machining the leading and tailing edges of an SPF/DB titanium hollow blade using free-form deformation

作     者：Zhengcai ZHAO Jiuhua XU Yucan FU Zhiqiang LI 

作者机构：College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and Astronautics Nanjing 210016 China Beijing Aeronautics Manufacturing Technology Research Institute Beijing 100024 China 

出 版 物：《Chinese Journal of Aeronautics》 (中国航空学报（英文版）)

年 卷 期：2018年第31卷第1期

页      面：178-186页

核心收录：

学科分类：08[工学] 082503[工学-航空宇航制造工程] 0825[工学-航空宇航科学与技术] 

基　　金：the financial supports of the National Natural Science Foundation of China(No.51475233) the Fundamental Research Funds for Central Universities(No.NZ2016107) the Jiangsu Innovation Program for Graduate Education(No.CXLX13_139) 

主　　题：Adaptive machining Blade geometry Free-form deformation Reconstruction Titanium 

摘      要：Titanium hollow blades are characterized with lightweight and high structural strength, which are widely used in advanced aircraft engines nowadays. Superplastic forming/diffusion bonding （SPF/DB） combined with numerical control （NC） milling is a major solution for manufacturing titanium hollow blades. Due to the shape deviation caused by multiple heat and pressure cycles in the SPF/DB process, it is hard to manufacture the leading and tailing edges by the milling process. This paper presents a new adaptive machining approach using free-form deformation to solve this problem. The actual SPF/DB shape of a hollow blade was firstly inspected by an on-machine measurement method. The measured point data were matched to the nominal SPF/DB shape with an improved ICP algorithm afterwards, by which the point-pairs between the measurement points and their corresponding points on the nominal SPF/DB shape were established, and the maximum modification amount of the final nominal shape was constrained. Based on the displacements between the point-pairs, an accurate FFD volume was iteratively calculated. By embedding the final nominal shape in the deformation space, a new final shape of the hollow blade was built. Finally, a series of measurement and machining tests was performed, the results of which validated the feasibility of the proposed adaptive machining approach.