Bidirectional Line-Structured Light Scanning Measurement Method for Maximum Thickness of Aero-Engine Blade Cross Sections Based on Profile Features

As a key component of aircraft engines, the complexity of blade features and the increasing production volumes pose significant challenges to the accuracy and efficiency of their profile inspections. In order to concurrently ensure accuracy and efficiency in measuring the maximum thickness of aero-engine blade cross sections, this study presents a measurement method employing bidirectional line-structured light scanning based on blade profile features. The designed bidirectional line structured light scanning system is tailored for measuring blade profile, enabling the simultaneous acquisition of coordinates for all points on both sides of the complete blade profile. A calibration method is introduced to determine the motion direction of the displacement stage within the laser scanning sensor (LSS) coordinate system, as well as the relative position of the bidirectional LSS coordinate system. This method aims to integrate the coordinates of measurement data points acquired into the world coordinate system. In addition, a feature-extracting algorithm, grounded in the inherent profile features of the blade, is proposed to accurately determine the maximum thickness of the blade cross section. The effectiveness of the proposed method is verified through the measurement of an aero-engine blade. A comparison between the maximum blade thickness measured by the proposed method and the results obtained by the coordinate measuring machine (CMM) reveals a maximum difference of 0.003 mm. The proposed method can be extended to other cross-sectional characteristic parameters on the contour of blades, contributing to the broader field of aero-engine design and manufacturing.