Acrylic Fiber Bundle Steam Drawing Width Control
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Solution Overview
Problem
Existing methods for producing carbon-fiber-precursor acrylic fiber bundles using steam drawing apparatuses face issues with yarn tension control, slipping between rolls, and non-uniform steam penetration, leading to unstable draw results, fiber breakage, and reduced strength, especially at high spinning speeds.
Innovation Solution
A method involving a fiber-opening device with a fluid jet-spray nozzle that sets specific flow rates and speeds, a width control device with grooved rolls, and a hot roll to maintain uniform fiber width and temperature, ensuring stable and high-speed drawing of carbon-fiber-precursor acrylic fiber bundles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If yarn tension is controlled by adjusting roll positions to achieve excellent opening effects, then fiber opening quality is improved, but yarn slipping occurs between rolls causing yarn damage and reduced strength
Solution Approach 1:
The patent replaces the mechanical tension control system (rolls and mechanical tensioning) with a pneumatic system. A pneumatic delivery device with adjustable airflow pressure and a pneumatic pressing device with adjustable pressing force are used to control yarn tension and opening quality without the slipping and damage caused by mechanical roll contact. The airflow pressure and pressing force can be independently adjusted to optimize both opening quality and yarn strength.
2Productivity
If high spinning speeds are used to increase productivity, then production efficiency is improved, but fiber breakage increases and strength decreases
Solution Approach 1:
The patent replaces mechanical tensioning systems with pneumatic control to reduce mechanical stress on fibers during high-speed spinning. The pneumatic delivery device provides controlled airflow that gently guides the yarn without the friction and impact of mechanical contact, while the pneumatic pressing device applies distributed pressure rather than concentrated mechanical force, reducing fiber breakage at high spinning speeds.
Solution Approach 2:
The pneumatic pressing device is positioned before the steam box to pre-compress and stabilize the yarn bundle, ensuring uniform structure before steam treatment. This preliminary cushioning prevents fiber breakage during subsequent high-speed processing by eliminating weak points and ensuring uniform stress distribution throughout the yarn bundle.
3Strength
If oil agents are applied during upper-stream production to obtain high-resistance carbon fibers, then fiber strength is improved, but uniform steam penetration is blocked causing non-uniform drawing performance
Solution Approach 1:
The pneumatic pressing device is positioned upstream before the steam box to compress and densify the yarn bundle in advance. This preliminary action creates a more uniform and compact structure that facilitates uniform steam penetration during the subsequent steam drawing process, overcoming the barrier effect of oil agents through pre-organized fiber arrangement rather than attempting to remove the oil agents.
4Productivity
If steam drawing is performed to achieve high draw ratio with less fuzz and end breakage, then productivity is improved, but control over bundle width and position is lost causing breakage
Solution Approach 1:
The patent incorporates a control system that monitors the yarn bundle width and position during steam drawing and provides feedback to the pneumatic delivery and pressing devices. This allows real-time adjustment of airflow pressure and pressing force to maintain consistent bundle dimensions and position, preventing breakage while achieving high draw ratios. The feedback loop ensures that productivity gains do not compromise manufacturing precision.
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 method achieves a high draw rate with stable and uniform results, reducing fiber breakage and maintaining strength, even at high spinning speeds, by ensuring controlled tension and uniform steam penetration.
Implementation Method 1
a fiber-opening device that opens fibers by jet-spraying a fluid from a jet-spray nozzle
Implementation Method 2
introducing the carbon-fiber-precursor acrylic fiber bundles into a steam box for heating
Data Source
Figure 1~3
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Figure 7~8
AI summary
A steam-drawing apparatus has supply roll 1 that transfers carbon-fiber-precursor acrylic fiber bundle (T) in a transfer direction of fiber bundle (T); fiber-opening device 2 for opening fiber bundle (T); width control device 3 for controlling the width of fiber bundle (T); steam box 4 to provide steam for heating fiber bundle (T) to a temperature that allows fiber bundle (T) to be drawn; and haul-off roll 5 that transfers fiber bundle (T) at a speed faster than that of supply roll 1. Using width control device 3 provided at a position between supply roll 1 and steam box 4, the width of fiber bundle (T) after passing through width control device 3 is set to be 65∼110% of the width of fiber bundle (T) before entering the supply roll. The present invention proposes a method for producing a carbon-fiber-precursor acrylic fiber bundle using such a steam-drawing apparatus capable of conducting a high-speed drawing process of carbon-fiber-precursor acrylic fiber bundles at a high draw rate with stable results.