Fiber Coating Sizing Die Geometry to Reduce Vortex Instability
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Solution Overview
Problem
High draw rates in optical fiber manufacturing lead to non-uniform and eccentric coatings due to unstable coating material vortices in conventional sizing dies, resulting in increased manufacturing costs and coating defects.
Innovation Solution
The use of sizing dies with reduced or eliminated convex walls and shorter taper regions, along with a conical ferrule design, stabilizes the coating material gyre, reducing coating rejection and centering forces, thereby improving coating concentricity and reducing the likelihood of flooding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional sizing dies with convex walls and longer taper regions are used, then coating material can be applied, but unstable vortices form leading to non-uniform and eccentric coatings
Solution Approach 1:
The patent removes the convex walls from the sizing die design, extracting the problematic geometric feature that caused unstable vortex formation. This elimination of the convex portion directly addresses the vortex instability issue while maintaining the essential coating function through the remaining tapered and cylindrical sections.
Solution Approach 2:
The patent modifies the geometric parameters of the sizing die, specifically reducing the taper region length and eliminating convex walls. These parameter changes transform the flow dynamics within the die, stabilizing the coating material vortex and producing uniform concentric coatings even at high draw rates.
2Productivity
If higher draw rates are used to reduce manufacturing cost, then productivity increases, but coating uniformity and concentricity deteriorate
Solution Approach 1:
The patent optimizes the sizing die geometry to dynamically adapt to high-speed coating conditions. The modified tapered section and eliminated convex walls create flow conditions that remain stable across a wider range of draw rates, allowing high productivity without sacrificing coating quality.
3Reliability
If conventional sizing die geometry is used, then coating application is possible, but flooding incidents occur reducing process reliability
Solution Approach 1:
The patent transforms the potential harmful effect of high draw rates into a benefit by optimizing the die geometry. The modified tapered section controls coating material flow in a way that prevents flooding while maintaining high-speed operation, converting what was previously a problematic condition into an advantageous operating regime.
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 design significantly reduces coating offsets and flooding incidents, leading to more stable and uniform coatings, even at higher draw speeds, and minimizes the size of the coating gyre, enhancing process stability and reducing manufacturing costs.
Implementation Method 1
stabilizes the coating material gyre, reducing coating rejection and centering forces
Implementation Method 2
The conical ferrule has a cross-section with inner walls angled at a half angle Θ and height L1
Data Source
Figure 1
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Figure 4
AI summary
One embodiment of the disclosure relates to a fiber coating apparatus having a fiber entrance opening, a conical section with walls tapered at half angles between 2 and 25° and height (also referred to as length herein) L1 between 0.25mm and 2mm, and a cylindrical land portion of diameter d2 between 0.1 and 0.5mm and height (length) L2 between 0.05 and 1.25mm.