Fiber-Reinforced Strand Twisting for Circular Cross-Section Control
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Solution Overview
Problem
Conventional fiber-reinforced strand manufacturing methods often result in a short twist pitch, leading to non-circular cross-sectional shapes and unstable quality with defects in external appearance and mechanical properties.
Innovation Solution
An apparatus and method that control the twist pitch and twist number to ensure a circular cross-section by twisting the fiber bundle within specific limits, maintaining a circularity variation of 5% or less, using a resin bath with impregnation and twisting regions to achieve high-quality fiber-reinforced strands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the reinforced fiber bundle is twisted with a short twist pitch after resin impregnation, then the twisting process is completed quickly, but the cross-sectional shape becomes non-circular and quality becomes unstable
Solution Approach 1:
The patent applies dynamics by making the twist pitch variable along the longitudinal direction of the fiber bundle. The twist pitch is set to be larger at the upstream side (near the resin bath) and smaller at the downstream side, creating a dynamic gradient that optimizes both circularity and productivity. This dynamic variation allows the fiber bundle to gradually adapt to twisting forces, maintaining circular cross-section during impregnation while achieving complete twisting downstream.
Solution Approach 2:
The patent implements local quality by applying different twist pitch characteristics to different regions along the fiber bundle length. The upstream region (in the resin bath) has a larger twist pitch to preserve circularity during impregnation, while the downstream region has a smaller twist pitch to achieve thorough twisting. This localized differentiation resolves the contradiction between maintaining shape and achieving complete twisting.
2Manufacturing precision
If the twist pitch is increased to maintain circular cross-section, then the cross-sectional shape remains circular, but the twisting process becomes slower and less effective
Solution Approach 1:
The dynamic variation of twist pitch along the longitudinal direction allows the system to optimize for circularity where needed (upstream with larger pitch) and for twisting efficiency where needed (downstream with smaller pitch). This dynamic approach eliminates the need to choose between the two conflicting requirements.
Solution Approach 2:
The twisting process is segmented into different zones along the fiber bundle length, with each zone having an optimized twist pitch. The upstream zone focuses on maintaining circularity during impregnation, while the downstream zone focuses on achieving thorough twisting. This segmentation allows both circularity and twisting efficiency to be optimized in their respective regions.
3Device complexity
If conventional twisting methods are used, then the process is simple, but defects in external appearance and mechanical properties occur
Solution Approach 1:
The dynamic twist pitch variation improves strand quality and reliability by ensuring proper resin impregnation and fiber alignment throughout the twisting process. The larger upstream pitch prevents defects during impregnation, while the smaller downstream pitch ensures thorough twisting, eliminating external appearance defects and mechanical property variations.
Solution Approach 2:
The patent applies preliminary action by establishing the appropriate twist pitch gradient before the twisting process begins. The resin bath is positioned to correspond with the upstream region of larger twist pitch, ensuring that impregnation and twisting occur in the optimal sequence and location, preventing quality defects before they occur.
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
The method ensures a circular cross-sectional shape, eliminating external appearance defects and variations in mechanical properties, resulting in a stable and high-quality fiber-reinforced strand.
Implementation Method 1
a resin bath means 7 for impregnating the reinforced fiber bundle 3 with the molten resin 5
Implementation Method 2
storing a molten thermoplastic resin, thereby impregnating the reinforced fiber bundle with the molten resin
Implementation Method 3
twisting the reinforced fiber bundle about a bundle center
Data Source
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AI summary
In a method of manufacturing a fiber-reinforced strand, the fiber-reinforced strand is so manufactured that the cross-section thereof becomes as circular as possible. The present invention concerns a method of causing a reinforced fiber bundle 3 to pass through a resin bath means 7 and, thereafter, twisting the reinforced fiber bundle 3. The resin bath means 7 includes an impregnation region 21 where the reinforced fiber bundle 3 is impregnated with a thermoplasti resin 5 and a twisting region 22 where the reinforced fiber bundle 3 after the resin impregnation can be twisted, and the reinforced fiber bundle 3 after the resin impregnation is twisted in such a manner that a twist pitch P imparted to the reinforced fiber bundle 3 after the resin impregnation within a length L in the twisting region 22 satisfies L/3 ≥ P ≥ 3.15/90×(dtex)1/2.