On-Line Optical Fiber Tensile Testing During Drawing
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Solution Overview
Problem
Current methods for evaluating optical fiber tensile strength during manufacturing are ineffective in detecting defects early, leading to high discard rates of both fibers and preforms, and result in wasted materials and resources due to off-line testing after the fiber has been produced.
Innovation Solution
Implementing an on-line tensile strength testing method that applies a lower tensile stress to the initial length of the drawn optical fiber, allowing for the detection of defects and anomalies in the preform and drawing process, thereby ensuring the quality of the fiber and reducing subsequent breakages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If off-line tensile strength testing is performed after fiber production, then defects can be detected, but high discard rates of fibers and preforms occur
Solution Approach 1:
The patent applies tensile strength testing during the fiber drawing process itself, before the fiber is fully produced and before off-line testing would occur. This preliminary action during manufacturing allows defects to be detected early, enabling immediate process adjustment and preventing the production of large quantities of defective fiber that would later be discarded.
Solution Approach 2:
The on-line tensile strength testing provides real-time feedback during the fiber drawing process. When defects are detected through the testing apparatus, the system can immediately signal for process adjustments or shutdowns, creating a closed-loop control system that prevents continued production of defective fiber and minimizes discard rates.
2Ease of manufacture
If on-line tensile strength testing is performed immediately after drawing, then the testing process is simplified, but many defects are not detected due to fiber resistance
Solution Approach 1:
The patent modifies the testing parameters by applying controlled tensile stress during the fiber drawing process rather than testing the fiber in its as-drawn state. This parameter change in the testing approach allows defects to manifest under stress conditions, improving detection accuracy while maintaining the simplicity of on-line testing during manufacturing.
Solution Approach 2:
The testing system dynamically applies tensile stress during the drawing process, creating variable stress conditions that reveal defects. This dynamic testing approach, where stress is applied in real-time during manufacturing, improves defect detection compared to static testing of as-drawn fiber, while maintaining process integration and simplicity.
3Measurement precision
If continuous on-line tensile testing is applied to the whole drawn fiber length, then all defects are detected, but the drawing process becomes discontinuous due to frequent breakages
Solution Approach 1:
The patent applies tensile testing to the fiber during the drawing process, but not necessarily to the entire fiber length with maximum stress throughout. The testing can be applied selectively or with controlled stress levels, providing sufficient defect detection while minimizing the likelihood of excessive breakages that would disrupt drawing continuity.
Solution Approach 2:
The testing apparatus may apply tensile stress periodically or at specific intervals during the drawing process rather than continuously at maximum levels. This periodic testing approach maintains drawing process continuity while still detecting defects through repeated stress applications, balancing productivity with comprehensive defect detection.
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 reduces the number of defective fibers and preforms, minimizing waste and increasing productivity by identifying and addressing issues early in the manufacturing process, ensuring the optical fibers meet desired tensile strength values.
Implementation Method 1
the optical fiber being drawn in a fiber drawing oven
Implementation Method 2
modifications of the cooling conditions
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A method of evaluation of an optical fiber (103) during manufacturing thereof, said method comprising: - subjecting (410) a predetermined initial length of the optical fiber to a predetermined first tensile stress while the optical fiber is being drawn from a fiber preform (101); - detecting (415) a number of fiber breakages occurring in said initial length of optical fiber; - if the detected number of fiber breakages exceeds a predetermined first threshold, stopping the fiber drawing process (430); - otherwise removing the first tensile stress from the optical fiber and continuing the drawing process until completion (420,425).