Hollow-Core Cane Drawing With Active Capillary Pressure Control

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Solution Overview

Problem

The manufacturing process of hollow-core photonic crystal fibers is hindered by unstable pressure fluctuations during the cane drawing process, leading to variations in the inner structure dimensions and significant material loss, which affects the yield and precision of the final product.

Innovation Solution

A method involving the assembly of a preform with a jacket and capillaries, insertion of pressurization tubes into the cavities, and active pressure control using a pressure connector to stabilize the dynamic pressure conditions, thereby controlling the dimensions of the inner structure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If active pressure control is implemented during cane drawing, then manufacturing precision and yield improve, but device complexity increases

Engineering Contradiction:
Improveinner structure dimensionsVSAvoidpressure control system
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The preform is segmented into multiple capillaries, each equipped with its own pressurization tube. This allows independent pressure control of each capillary, enabling precise dimensional control of the inner structure while distributing the complexity across multiple simple, identical components rather than one complex control system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Pressurization tubes are introduced as intermediary elements that connect the external pressure control system to the internal cavities of the preform. These tubes act as mediators, transmitting controlled pressure from the pressure connector to the capillaries, thereby enabling precise pressure control without direct complex interaction between the control system and the delicate capillary structure.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Loss of substance

If pressure control is implemented during drawing, then material loss is reduced, but the manufacturing process becomes more complex

Engineering Contradiction:
Improvepreform materialVSAvoidpressure control system
Core Design Contradiction:
Loss of substanceVSDevice complexity

Solution Approach 1:

Pressurization tubes are inserted into the capillaries during preform assembly, before the drawing process begins. This preliminary action ensures that the pressure control capability is already in place, allowing immediate prevention of material loss when drawing starts, rather than requiring complex retroactive adjustments during the drawing process.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The pressure control system is designed to be self-regulating, where the pressurization tubes and sealing mechanism work autonomously to maintain appropriate pressure within the capillaries during drawing. This reduces the need for complex external control systems while still achieving the goal of minimizing material loss.

Inventive Principle:
Principle #25Self-service

3Manufacturing precision

If pressurization tubes are inserted into capillaries, then dimension control improves, but the assembly process becomes more complex

Engineering Contradiction:
Improvecapillary dimensionsVSAvoidpreform assembly
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The assembly process is segmented into standardized steps: preparing the preform with capped capillary ends, inserting pressurization tubes through the caps into the capillaries, and sealing the tube ends. This segmentation into simple, repeatable steps makes the assembly process more manageable and less complex than it would appear at first glance.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The pressurization tubes are designed as simple, inexpensive components that can be easily inserted and sealed. Their simplicity allows for straightforward assembly without requiring complex alignment or positioning mechanisms, thereby reducing the overall complexity of the assembly process while still achieving the goal of improved dimension control.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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 eliminates dimension variations and reduces material loss, significantly increasing the yield of canes within specification by up to 50% and ensuring precise tailoring of the internal structure.

Implementation Method 1

active pressure control using a pressure connector to stabilize the dynamic pressure conditions

Methodology Applied
Scientific EffectPressure control:

Implementation Method 2

sealing the pressurization tube within the cavity with a sealing agent

Methodology Applied
Scientific EffectSealing:

Implementation Method 3

creating a tapered portion of the preform at the first end

Methodology Applied
Scientific EffectTapering:

Data Source

PatentEP4656603A1A method of manufacturing a hollow core cane for use in manufacturing a hollow-core photonic crystal fiber
Publication Date: 2025.12.03 ASML NETHERLANDS BV
  • EP4656603A1 patent drawingFigure 1
  • EP4656603A1 patent drawingFigure 2~3
  • EP4656603A1 patent drawingFigure 4~5

AI summary

A method of manufacturing a hollow core cane, the method comprising: assembling a preform comprising a jacket 114 with a hollow inner structure 110, wherein a plurality of capillaries 105 are located within the hollow inner structure 110, the preform having a first end 104 and a second end; creating a tapered portion 116 of the preform at the first end 104; slicing the preform within the tapered portion to thereby create a sliced end 118 of the preform and expose cavities of the plurality of capillaries and the hollow inner structure 110; inserting a pressurization tube into one or more of the cavities at the sliced end 118 of the preform; sealing the least one pressurization tube 120 within the one or more cavities with a sealing agent; coupling the least one pressurization tube 120 to a pressure connector; and drawing a hollow core cane from the preform whilst providing pressure to the one or more cavities using the pressure connector.