Partially separated fiber bundle and method of manufacturing same
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Solution Overview
Problem
Existing methods for partially separating fiber bundles into a desired number of single yarns often result in uneven width variations and mechanical property inconsistencies in fiber-reinforced resin molding materials, particularly when using large tow fibers with many single yarns, leading to difficulties in handling and conveyance due to fluff generation and entanglement.
Innovation Solution
A partially separated fiber bundle is created with a controlled ratio of separated to unseparated sections, using a fiber separating device with projections arranged in a phase-shifted manner to intermittently form separated and unseparated sections, ensuring a uniform fiber separating number per unit width, and applying a sizing agent to enhance mechanical properties and prevent fluffing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a fiber bundle with a large number of single yarns is used, then the fluidity during molding is improved, but the mechanical properties of the molded article deteriorate
Solution Approach 1:
The fiber bundle is divided into multiple sub-bundles by partially separating it into separated fiber sections and unseparated fiber sections. This segmentation allows the molding material to maintain good fluidity during molding while providing sufficient reinforcement for mechanical properties through the distributed fiber arrangement.
2Adaptability or versatility
If a fiber bundle is longitudinally slitted over the entire length, then the number of single yarns can be adjusted, but the handling becomes difficult due to fluff generation and entanglement
Solution Approach 1:
Instead of uniformly slitting the entire fiber bundle length, the invention applies localized partial separation only to specific sections. This creates separated fiber sections with adjusted yarn numbers where needed, while maintaining unseparated sections that prevent fluff generation and handling difficulties.
Solution Approach 2:
The fiber bundle is partially separated rather than fully slitted along its entire length. This partial action achieves the desired adjustment of single yarn numbers in specific regions while avoiding the excessive separation that would cause fluffing and entanglement problems throughout the entire bundle.
3Productivity
If a fiber separating device with projections is stuck into the fiber bundle, then separated fiber sections can be obtained, but large variation of width occurs when cut into chopped fiber
Solution Approach 1:
The fiber separating device uses projections that are shifted in the longitudinal direction to create a phase-shifted separation pattern. This dynamic arrangement allows the separated fiber sections to maintain consistent width characteristics when cut into chopped fiber, improving manufacturing precision while preserving continuous production capability.
Data Source
AI summary
A partially separated fiber bundle includes a separated fiber section and an unseparated fiber section, being configured to give a ratio Amax/Amin of 1.1 or larger and 3 or smaller, when the number of fiber bundles contained in the width direction of the partially separated fiber bundle (fiber separating number: Nn) measured at a freely selected point Pn (where, n represents an integer of 1 to 100, and freely selected points Pn and Pn+1, excluding n=100, being 50 cm or more away from each other), is divided by a full width of Wn of the partially separated fiber bundle, to calculate the fiber separating number per unit width An, and assuming its maximum value as Amax and its minimum value as Amin.