Optical Fiber Drawing Tower Swing Guide Roller Frequency Control

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Solution Overview

Problem

Existing methods for manufacturing optical fibers struggle to suppress variations in the outer diameter of glass without compromising productivity and yield, particularly due to vibrations in the drawing tower and twisting processes.

Innovation Solution

A method involving the use of a swing guide roller with feedback control, where the swing frequency is adjusted to prevent overlap between peaks in the frequency spectrum of the glass outer diameter variation, allowing for precise control of the drawing conditions to minimize diameter variations without reducing productivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the drawing speed is reduced or twisting is minimized to suppress glass outer diameter variation, then manufacturing precision improves, but productivity deteriorates

Engineering Contradiction:
Improveglass outer diameter variationVSAvoidproduction speed
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent applies periodic vibration to the drawing tower at a specific frequency (20-100 Hz) to counteract the harmful vibrations causing glass outer diameter variation. By introducing controlled mechanical vibration, the system suppresses resonance and stabilizes the drawing process, achieving both high manufacturing precision and maintained productivity without requiring reduced drawing speed or minimized twisting.

Inventive Principle:
Principle #18Mechanical vibration

Solution Approach 2:

The patent changes the operational parameters of the drawing tower by applying periodic vibration at optimized frequencies (20-100 Hz) and amplitudes (0.01-1 mm). This parameter adjustment allows the system to operate at high drawing speeds while suppressing diameter variation, resolving the contradiction between productivity and manufacturing precision.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If a vibration suppressing mechanism with time constant of 1 second or less is provided between the drawing tower and optical fiber preform, then glass outer diameter variation is suppressed, but device complexity increases

Engineering Contradiction:
Improveglass outer diameter variationVSAvoidvibration suppressing mechanism
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent implements a feedback control system where vibration sensors detect the actual vibration state of the drawing tower, and the control unit adjusts the vibration frequency and amplitude in real-time. This feedback mechanism automatically suppresses glass outer diameter variation by adapting to changing conditions, achieving high manufacturing precision without requiring complex mechanical vibration suppressing structures.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces complex mechanical vibration suppression mechanisms with an electronic control system that uses sensors and actuators to actively control vibrations. This substitution reduces mechanical complexity while achieving effective vibration suppression and maintaining high manufacturing precision.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If the swing frequency of the guide roller is increased to improve twisting effectiveness, then PMD suppression improves, but glass outer diameter variation worsens due to peak overlap

Engineering Contradiction:
Improvepolarization mode dispersion suppressionVSAvoidglass outer diameter variation
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent dynamically adjusts the swing frequency of the guide roller within the range of 20-100 Hz based on real-time vibration detection. By making the swing frequency adjustable rather than fixed, the system can optimize both PMD suppression and glass outer diameter control, avoiding peak overlap while maintaining effective twisting action.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The feedback control system monitors the vibration state and automatically adjusts the guide roller swing frequency to avoid resonance peaks that cause glass outer diameter variation. This ensures that PMD suppression remains effective while preventing diameter variation worsening, resolving the contradiction between reliability and manufacturing precision.

Inventive Principle:
Principle #23Feedback

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 effectively suppresses the variation in the glass outer diameter, maintaining high productivity and yield by ensuring the swing frequency of the roller does not overlap with inherent manufacturing frequencies, thereby reducing amplitude and improving diameter consistency.

Implementation Method 1

periodically swinging a guide roller and twisting an optical fiber

Methodology Applied
Scientific EffectMechanical vibration: Vibration

Implementation Method 2

adjusting the second drawing condition so as to satisfy fn fm + wm / 2, where fm is a frequency of the first peak, wm is a full width at half maximum of the first peak, and fn is a frequency of the second peak

Methodology Applied
Scientific EffectResonance: Resonance

Data Source

PatentEP3936483B1Method for manufacturing optical fiber
Publication Date: 2024.09.25 SUMITOMO ELECTRIC INDUSTRIES LTD
  • EP3936483B1 patent drawingFigure 1
  • EP3936483B1 patent drawingFigure 2
  • EP3936483B1 patent drawingFigure 3

AI summary

A method for manufacturing an optical fiber includes: heating an optical fiber preform to draw glass fiber; measuring an outer diameter of the glass fiber to obtain a function of time; transforming the function of time into a function of frequency; identifying a first peak caused by a first drawing condition and a second peak caused by a second drawing condition in the function of frequency; and adjusting the second drawing condition so as to satisfy fn < fm - wm / 2 or fn > fm + wm / 2, where fm is a frequency of the first peak, wm is a full width at half maximum of the first peak, and fn is a frequency of the second peak.