Carbon Fiber Bundle Production via Controlled Traveling Pitch
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing methods for producing carbon fiber bundles face challenges in increasing production capacity while maintaining quality, as they require larger high-temperature furnaces and result in weak carbon fibers due to partial breakage and contamination from decomposed products, leading to unstable quality and increased equipment costs.
Innovation Solution
A method involving a flame-retarding step, a precarbonization step, and a carbonization step, where precursor fiber bundles are heat-treated in oxidizing and inert gas atmospheres respectively, with controlled traveling pitches to prevent overlap and contamination, using grooved rolls and angle-adjustable rolls to maintain fiber bundle alignment and reduce traveling pitch variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the baking rate is increased to increase production capacity, then productivity is improved, but the heat of reaction is stored inside the fiber bundles causing fire hazards and quality degradation
Solution Approach 1:
The fiber bundles are divided into multiple groups that are spaced apart during heat treatment, preventing heat accumulation while maintaining high throughput. Multiple groups are simultaneously treated in sequence through the flame-retarding oven without overlapping
Solution Approach 2:
The invention introduces spatial arrangement in the width direction by spacing multiple groups of fiber bundles apart, rather than simply increasing the length of individual bundles. This dimensional approach allows parallel processing while maintaining safe heat dissipation
2Productivity
If the length of precursor fiber bundles is increased to increase production capacity, then productivity is improved, but the fiber bundles require repeated passage through the flame-retarding oven increasing process complexity
Solution Approach 1:
Instead of using one extremely long bundle requiring multiple passes, the invention segments the production into multiple medium-length bundles processed simultaneously in parallel, eliminating the need for turn-over rolls and repeated passages
Solution Approach 2:
Multiple fiber bundle groups are merged into a single simultaneous processing operation, achieving the throughput of long bundles processed repeatedly without the mechanical complexity of turn-over mechanisms
3Productivity
If multiple fiber bundles are simultaneously fed to the furnace, then productivity is improved, but the furnaces must be larger increasing equipment costs
Solution Approach 1:
The invention arranges multiple fiber bundle groups in the width direction with appropriate spacing, utilizing lateral space rather than increasing furnace length. This allows simultaneous processing of multiple bundles without proportionally increasing furnace volume
Solution Approach 2:
Different spatial zones within the furnace are utilized efficiently by positioning fiber bundle groups at optimized locations with appropriate spacing, ensuring uniform heat treatment while maximizing furnace utilization without overall size increase
4Manufacturing precision
If the traveling pitch of fiber bundles is decreased to maintain alignment, then manufacturing precision is improved, but the heat storage due to heat of reaction cannot be removed
Solution Approach 1:
Fiber bundles are grouped and spaced apart with clearance between groups, maintaining precise alignment within groups while preventing heat accumulation through inter-group spacing
Solution Approach 2:
Different spatial regions are assigned different functions: tight spacing within groups for alignment precision, wide spacing between groups for heat dissipation, optimizing both requirements simultaneously
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 allows for stable and high-productivity carbon fiber production without the need for larger furnaces, reducing equipment costs and maintaining fiber quality by controlling the traveling pitches and alignment of fiber bundles throughout the processing stages.
Implementation Method 1
the precursor fiber bundles undergo oxidation reaction to generate heat
Implementation Method 2
the flame-retardant fiber bundles are heat-treated in the oxidizing atmosphere
Implementation Method 3
the flame-retardant fiber bundles are sequentially passed for carbonization through an inert atmosphere furnace
Data Source
AI summary
The invention provides a method for producing carbon fiber bundles excellent in productivity without impairing the quality in the process for producing carbon fibers. The method includes a flame-retarding step, a precarbonization step, and a carbonization step. When traveling pitches of the fiber bundles in the flame-retarding step, precarbonization step and carbonization step are represented by P1, P2 and P3, respectively, 0.8≦P2/P1≦1.0 and 0.4≦P3/P1≦0.8 are satisfied; when traveling pitches of the fiber bundles at the inlet and the outlet of a heat treatment section of a precarbonization furnace are represented by P11 and P12, respectively, 0.40≦(P12/P11)≦0.90 is satisfied; or when traveling pitches of the fiber bundles at the inlet and the outlet of a heat treatment section of a carbonization furnace are represented by P13 and P14, 0.40≦(P14/P13)≦0.90 is satisfied.