Post-draw optical fiber coating curing with LED subsystems
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Solution Overview
Problem
In optical fiber manufacturing, high-speed production challenges the full curing of primary and secondary coatings due to reduced exposure time to UV light and increased temperature, leading to incomplete curing, especially when the secondary coating is opaque and applied over a non-cured primary coating.
Innovation Solution
A post-draw tower coating curing system that includes a coating curing unit with LED curing subsystems positioned along the fiber path between the draw tower output and the takeup system, providing additional UV curing to ensure full curing of both primary and secondary coatings by extending the curing time and optimizing light exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If fiber draw speed is increased to improve productivity, then throughput is improved, but UV curing effectiveness deteriorates due to reduced exposure time and increased temperature
Solution Approach 1:
The curing process is divided into two distinct stages: first curing within the draw tower using conventional lamps, and second curing after the draw tower using additional UV lamps. This segmentation allows each curing stage to be optimized independently, enabling high-speed production while ensuring complete curing of the primary coating beneath the secondary coating.
Solution Approach 2:
The invention extends the curing process from a single spatial location (within the draw tower) to multiple spatial locations (both within and after the draw tower). By adding curing lamps in the post-draw tower region, the system creates an extended curing zone that provides additional UV exposure time without restricting fiber draw speed, effectively adding a temporal dimension to the curing process.
2Device complexity
If secondary coating is applied over primary coating in wet-on-wet manner to minimize tower height, then device complexity is reduced, but primary coating curing is hindered by opacity of secondary coating
Solution Approach 1:
The system performs preliminary curing of the primary coating within the draw tower before the secondary coating is fully opaque, then continues curing after the draw tower. This preliminary action ensures that UV light can penetrate the secondary coating more effectively during the post-draw tower curing stage, as the primary coating has already begun to set, while still achieving complete curing despite the opacity barrier.
Solution Approach 2:
The curing action continues uninterrupted from within the draw tower through to after the draw tower. The post-draw tower UV lamps maintain continuous UV exposure on the primary coating even as it passes beneath the opaque secondary coating, ensuring that the curing process never stops and that complete curing is achieved regardless of the wet-on-wet application method.
3Ease of operation
If draw tower height is limited to maintain compact structure, then ease of operation is improved, but sufficient UV curing exposure time cannot be achieved at high draw speeds
Solution Approach 1:
The curing exposure is segmented into two phases: a first phase within the compact draw tower and a second phase after the draw tower. This segmentation allows the draw tower itself to remain compact and easy to operate, while the extended curing phase after the tower provides the additional exposure time needed for high-speed production without requiring an increased tower height.
Solution Approach 2:
The invention extends the curing exposure beyond the vertical dimension of the draw tower by adding a horizontal or extended vertical curing zone after the tower. This dimensional extension provides additional curing time and space without increasing the draw tower's height, maintaining compact operation while achieving sufficient UV exposure for complete curing at high draw speeds.
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
Ensures complete curing of both primary and secondary coatings, enhancing the effectiveness of the coating process and maintaining high-speed production without increasing the draw tower height, by providing additional curing time and focused UV light exposure.
Implementation Method 1
One or more curing lamps that produce ultraviolet (UV) light may follow the coating applicators
Implementation Method 2
The effectiveness of UV curing may depend on various factors, including temperature
Data Source
AI summary
Post-draw tower coating curing provides additional curing to an optical fiber coating after the fiber exits the bottom or output end of an optical fiber draw tower. A system may include a draw tower and a coating curing unit. The draw tower has at least one coating applicator. The coating curing unit may be located along a fiber path between the output end of the draw tower and a fiber takeup system.