Automated 3D Inspection of Woven Preform Grids
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Solution Overview
Problem
Current non-destructive testing methods for woven preforms, such as turbine engine fan blades, are time-consuming and unreliable due to manual operation and inability to accurately measure intersections in three-dimensional curved structures.
Innovation Solution
An automated method using first and second marker threads with distinct light-reflection properties, imaged by two sensors with angled optical axes, allowing for precise triangulation and comparison of intersection coordinates in three-dimensional space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If manual laser aiming is used to measure intersection positions, then the measurement process is simple to implement, but the inspection time becomes lengthy and reliability decreases
Solution Approach 1:
The patent replaces the manual mechanical laser aiming process with an automated optical measurement system. Two image sensors capture images of the grid formed by marker threads, and a processing unit automatically calculates intersection positions through image processing and triangulation, eliminating manual operation while improving reliability and reducing inspection time.
Solution Approach 2:
The patent creates optical copies (images) of the physical grid structure using image sensors. Instead of manually pointing a laser at physical intersections, the system captures digital images of the marker threads and computationally determines intersection positions from these copies, enabling automated and repeatable measurements.
2Device complexity
If a single image sensor is used to capture grid intersections, then the device complexity is low, but the measurement precision in three-dimensional space is insufficient
Solution Approach 1:
The patent transitions from two-dimensional image capture to three-dimensional position measurement by introducing a second image sensor. The two sensors are positioned at different locations with their optical axes forming an angle, enabling triangulation to calculate the third dimension (depth) of intersection positions, thereby achieving accurate 3D measurement.
Solution Approach 2:
The patent introduces the angle between the two optical axes as an intermediary parameter that enables three-dimensional reconstruction. By knowing the relative positions and orientations of the two sensors, the system can compute spatial coordinates of intersections that a single sensor cannot determine alone.
3Illumination intensity
If marker threads with similar light-reflection properties to preform threads are used, then the marker threads are less visible in images, but the contrast between marker threads and preform threads is insufficient
Solution Approach 1:
The patent applies the principle of color/reflectivity changes by specifying that marker threads have light-reflection properties different from the preform threads. This creates sufficient contrast in the captured images, allowing the processing unit to clearly distinguish marker thread intersections from the background preform structure, thereby improving measurement precision.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly increases precision and repeatability of measurements, enabling accurate assessment of fibre density and orientation without manual intervention, suitable for complex curved preforms.
Implementation Method 1
the first and second threads having light-reflection properties different from those of the threads of the preform and being woven with the threads of the preform so as to form a surface grid on a given area of the preform
Implementation Method 2
illuminating the given area of the preform and acquiring, with each image sensor, an image of the grid of first and second marker threads
Data Source
AI summary
An automated method for the non-destructive testing of a woven preform for the manufacture of a turbine engine part and including a plurality of first marker threads intertwined with second marker threads, the first and second threads having light-reflecting properties that are different from those of the threads of the preform and being woven with the threads of the preform so as to form a surface grid on a given area of the preform. The method includes determining, with a plurality of consecutive steps, the spatial coordinates of the intersections between the first and second marker threads.