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Acta Aeronautica et Astronautica Sinica ›› 2023, Vol. 44 ›› Issue (17): 428212-428212.doi: 10.7527/S1000-6893.2023.28212

• Material Engineering and Mechanical Manufacturing • Previous Articles    

3D measurement of chemical milling plastic film pattern by coupling image grayscale and phase information

Pan ZHANG1, Yong WANG1, Kai ZHONG1, Jianjun JIANG2, Wufei YANG2, Zhongwei LI1,3()   

  1. 1.State Key Laboratory of Material Processing and Die & Mould Technology,School of Materials Science and Engineering,Huazhong University of Science and Technology,Wuhan 430074,China
    2.Chengdu Aircraft Industrial (Group) Co. Ltd. Chengdu 610000,China
    3.Research Institute of Huazhong University of Science and Technology in Shenzhen,Shenzhen 518063,China
  • Received:2022-11-01 Revised:2022-11-23 Accepted:2023-02-13 Online:2023-09-15 Published:2023-05-12
  • Contact: Zhongwei LI E-mail:zwli@hust.edu.cn
  • Supported by:
    Shenzhen Fundamental Research Program(JCYJ20210324142007022);Key Research and Development Program of Hubei Province(2021BAA049)

Abstract:

In the field of aerospace, multiple engravings for thin-walled metal structural parts are required to generate structures such as bosses and ribs during the chemical milling process. The 3D measurement of the processing pattern can not only evaluate the processing accuracy, but also provide basic data for parameter optimization such as trajectory planning and engraving process, which therefore, is a key technology to ensure the manufacturing quality of chemical milling parts. The existing measurement methods mainly include manual template comparison, passive binocular reconstruction, and 3D point cloud analysis, which can realize the detection of basic parameters like contour size; however, there are still some major problems in measurement accuracy and integrity. To solve these problems, on the basis of structured light and passive binocular 3D measurement, this paper proposes a 3D measurement method based on gray-phase change information for chemical milling glue film. Firstly, the gray-phase change characteristics of the engraved pattern’s adjacent area is analyzed to construct the corresponding mathematical model. Then, on this basis, a snake model based on the gray-phase information (Gray-Phase snake, GP snake)) of the left and right camera images is proposed to realize the high-precision extraction of the center line of the engraved pattern, and overcome the problem of inaccurate centerline extraction caused by uneven grayscale changes and inconsistent viewing of the left and right cameras. Finally, the 3D reconstruction of the contour is realized according to the phase matching, which solves the problem of incomplete reconstruction at the upper and lower edges of the traditional method, and ensures the accuracy and stability of the pattern measurement. The experimental results show that the proposed method can achieve the complete 3D reconstruction of the centerline of patterned adhesive films in chemical milling, with the high accuracy of 0.036 mm.

Key words: chemical milling and engraving, 3D contour measurement, active contour, structured light, accuracy detection

CLC Number: