随着制造理念和制造水平的不断提高，大量复合制造工艺背景下的近净成形叶片被应用到现役或在研的航空发动机中。该类叶片是典型的复杂薄壁结构零件，无精确定位基准，且成形一致性差。采用传统叶身定位，加工后的前/后缘、榫齿形状和位置精度均难以保证，从而导致产品一致性差，易超差与合格率低。针对以上问题，提出一种面向自适应加工的复杂薄壁结构零件工艺几何模型重构方法。首先，建立复杂曲面的采样点分布模型，快速获取叶片精确成型区域的位置和形状；其次，提出基于特征曲线相似变形的模型重构算法，精确重构前/后缘非精确成型区域的工艺几何模型；最后，通过精锻叶片自适应加工试验进行验证。试验结果表明：该方法可有效满足以精锻叶片为代表的复杂薄壁构件自适应加工要求。
With continuous improvement of manufacturing concepts and levels, a large number of near-net-shape blades produced by multi-manufacturing technologies have been applied to in-service or in-development aero-engine. However, by the reason of typical complex thin-walled structure parts, no accurate positioning datum and poor forming consistency of the precision forging blade, the machined leading edge and trailing edge, blade tenon shape and the positional accuracy are generally difficult to be guaranteed using the pressure and suction surfaces with variant shapes as the positioning references, which leads to poor consistency, low pass rate, and easy out-of-tolerance of final productions. In order to solve the above problems, a model construction method of complex thin-wall structure parts for adaptive machining is proposed. Firstly, a distribution model of sampling points on complex surface is established to quickly obtain the position and shape of the precision forged blade. Secondly, a model reconstruction algorithm is proposed based on the similar deformation of the characteristic curve, in order to reconstruct the geometry model of the inexact molding area at the leading edge and trailing edge. Finally, this approach is verified by adaptive machining of precision forged blade. The results show that this method can effectively meet the requirements of the adaptive machining of complex thin-wall structure parts represented by precision forged blades.
[1] LU B, OU H, ARMSTRONG C G, et al. 3D Die shape optimisation for net-shape forging of aerofoil blades[J]. Materials & Design, 2009, 30(7):2490-2500.
[2] XIAO G J, HUANG Y. Equivalent self-adaptive belt grinding for the real-R edge of an aero-engine precision-forged blade[J]. The International Journal of Advanced Manufacturing Technology, 2016, 83(9-12):1697-1706.
[3] 任军学, 冯亚洲, 米翔畅, 等. 航空发动机精锻叶片自适应数控加工技术[J]. 航空制造技术, 2015, 58(22):52-55, 59. REN J X, FENG Y Z, MI X C, et al. Adaptive techniques in CNC machining of aeroengine precision forging blades[J]. Aeronautical Manufacturing Technology, 2015, 58(22):52-55, 59(in Chinese).
[4] GAO J, CHEN X, YILMAZ O, et al. An integrated adaptive repair solution for complex aerospace components through geometry reconstruction[J]. The International Journal of Advanced Manufacturing Technology, 2008, 36(11-12):1170-1179.
[5] 冯亚洲, 任军学, 梁永收, 等. 多目标约束的精锻叶片几何重构优化算法[J]. 航空学报, 2018, 39(7):421844. FENG Y Z, REN J X, LIANG Y S, et al. Multi-objective optimization algorithm for geometric reconstruction of precision forged blade[J]. Acta Aeronautica et Astronautica Sinica, 2018, 39(7):421844(in Chinese).
[6] ZHANG D H, ZHANG Y, WU B H. Research on the adaptive machining technology of blisk[J]. Advanced Materials Research, 2009, 69-70:446-450.
[7] JIANG R S, WANG W H, ZHANG D H, et al. A practical sampling method for profile measurement of complex blades[J]. Measurement, 2016, 81:57-65.
[8] LIN X J, JIANG S, LIU X Z, et al. The CMM measurement path planning for blade surface based on the contour measurement[C]//2011 Second International Conference on Digital Manufacturing & Automation. Piscataway:IEEE Press, 2011:1228-1232.
[9] 牟鲁西. 复杂曲面零件在机测量关键技术研究与应用[D]. 武汉:华中科技大学, 2012. MOU L X. Study on key technologies of complex surfaces on machine measurement and application[D]. Wuhan:Huazhong University of Science and Technology, 2012(in Chinese).
[10] LI S. Adaptive sampling and mesh generation[J]. Computer-Aided Design, 1995, 27(3):235-240.
[11] 潘金川. 整体叶轮的CMM测量规划与仿真技术研究[D]. 南京:南京航空航天大学, 2014. PAN J C. Research on planning and simulation of CMM measuring the integral impeller[D]. Nanjing:Nanjing University of Aeronautics and Astronautics, 2014(in Chinese).
[12] 刘佳. 叶片复杂曲面原位测量关键技术研究[D]. 长春:吉林大学, 2016. LIU J. Research on the key technology of in situ measurement for blade complex surface[D]. Changchun:Jilin University, 2016(in Chinese).
[13] 蔺小军, 单晨伟, 王增强, 等. 航空发动机叶片型面三坐标测量机测量技术[J]. 计算机集成制造系统, 2012, 18(1):125-131. LIN X J, SHAN C W, WANG Z Q, et al. Measurement techniques of coordinate measuring machine for blade surface of aero-engine[J]. Computer Integrated Manufacturing Systems, 2012, 18(1):125-131(in Chinese).
[14] RONG Y, XU J T, SUN Y W. A surface reconstruction strategy based on deformable template for repairing damaged turbine blades[J]. Proceedings of the Institution of Mechanical Engineers, Part G:Journal of Aerospace Engineering, 2014, 228(12):2358-2370.
[15] LI L L, LI C B, TANG Y, et al. An integrated approach of reverse engineering aided remanufacturing process for worn components[J]. Robotics and Computer-Integrated Manufacturing, 2017, 48:39-50.
[16] 蔺小军, 陈悦, 王志伟, 等. 面向自适应加工的精锻叶片前后缘模型重构[J]. 航空学报, 2015, 36(5):1695-1703. LIN X J, CHEN Y, WANG Z W, et al. Model restructuring about leading edge and tailing edge of precision forging blade for adaptive machining[J]. Acta Aeronautica et Astronautica Sinica, 2015, 36(5):1695-1703(in Chinese).
[17] 程云勇, 王嫔, 刘鹏军, 等. 基于误差控制的薄壁叶片椭圆弧形前后缘建模方法[J]. 计算机辅助设计与图形学学报, 2016, 28(1):155-161. CHENG Y Y, WANG P, LIU P J, et al. An error control based modeling method for ellipse leading edge and trailing edge reconstruction of thin-walled blade[J]. Journal of Computer-Aided Design & Computer Graphics, 2016, 28(1):155-161(in Chinese).
[18] FENG Y Z, REN J X, LIANG Y S. Prediction and reconstruction of edge shape in adaptive machining of precision forged blade[J]. The International Journal of Advanced Manufacturing Technology, 2018, 96(5-8):2355-2366.
[19] WANG D X, WEN X L, ZHAO Y B. Localization and profile error evaluation of freeform surface based on CAD model-directed measurement[J]. Optics and Precision Engineering, 2012, 20(12):2720-2727.
[20] 冯亚洲. 航空发动机精锻叶片自适应加工工艺几何模型构建[D]. 西安:西北工业大学, 2018. FENG Y Z. Processing model construction of adaptive machining for precision forged blades of aero-engines[D]. Xi'an:Northwestern Polytechnical University, 2018(in Chinese).
[21] 丁汉, 朱利民. 复杂曲面数字化制造的几何学理论和方法[M]. 北京:科学出版社, 2011. DING H, ZHU L M. Geometric theories and methods for digital manufacturing of complex surfaces[M]. Beijing:Science Press, 2011(in Chinese).
[22] PIEGL L, TILLER W. The NURBS book[M]. Berlin, Heidelberg:Springer, 1997.
CJA