Partially separated fiber bundle, production method for partially separated fiber bundle, fiber-reinforced resin molding material using partially separated fiber bundle, and production method for fiber-reinforced resin molding material using partially separated fiber bundle
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for producing fiber bundles with an optimal number of single fibers struggle to balance flowability and mechanical properties during molding, often resulting in limited adjustment ranges, yarn breakage, and difficulties in handling and conveying fiber bundles, especially with large tows and twisted fibers.
Innovation Solution
A partially separated fiber bundle is created with alternately formed separation-processed and not-separation-processed sections, where the rate of single fibers in not-separation-processed regions is controlled to 67% or less, allowing for continuous and stable slitting without rotary blade exchange, and a method involving a separation means with projected parts that penetrate and remove from the fiber bundle to achieve this optimal distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a fiber bundle with a large number of single fibers is used, then flowability at the time of molding is improved, but mechanical properties of the molded article deteriorate
Solution Approach 1:
The fiber bundle is divided into multiple sub-bundles with different numbers of single fibers through the separation means. This segmentation allows the creation of a mixed bundle containing both thin sub-bundles (for improved flowability) and thick sub-bundles (for maintained mechanical properties), resolving the contradiction between flowability and mechanical strength in the molded article.
2Adaptability or versatility
If disk-shaped rotary blades are used for longitudinal slitting, then the number of single fibers can be adjusted, but the fiber bundle becomes difficult to handle and convey due to loss of convergence property
Solution Approach 1:
Instead of continuous longitudinal slitting that destroys convergence, the invention segments the slitting process into intermittent sections. The separation means is penetrated only at specific positions along the fiber bundle length, creating separated sections while preserving not-separated sections that maintain the convergence property necessary for easy handling and conveying.
Solution Approach 2:
The separation is applied locally at specific positions rather than uniformly along the entire fiber bundle. This local quality approach ensures that only certain sections are separated while other sections retain their original convergence property, allowing the fiber bundle to maintain handleability while still achieving the desired adjustment of single fiber number in separated regions.
3Productivity
If longitudinal slitting is performed on twisted fiber bundles, then the fiber bundle is cut at small lengths and continuous longitudinal slitting cannot be performed
Solution Approach 1:
The invention performs preliminary detection of twist positions in the fiber bundle before the separation means is penetrated. By detecting twist in advance and controlling the penetration timing to avoid these positions, the system enables continuous longitudinal slitting without being interrupted by twist-induced cutting, thereby maintaining both productivity and appropriate fiber bundle section lengths.
4Adaptability or versatility
If rotary blades are used for separation, then the number of single fibers can be adjusted, but the blades require periodic exchange when reaching cutting life
Solution Approach 1:
The invention replaces expensive rotary blades with a cheaper separation means consisting of projected parts that can be easily replaced. These projected parts have a shorter service life but are much less costly and simpler to replace than rotary blades, reducing both the frequency and complexity of maintenance operations while still achieving the desired fiber bundle separation and configuration adjustment.
Data Source
AI summary
A partially separated fiber bundle includes separation-processed sections, each divided into a plurality of bundles of at least three bundles, and not-separation-processed sections, that are alternately formed along the lengthwise direction of a fiber bundle that comprises a plurality of single fibers. The partially separated fiber bundle is characterized in that, at any width-direction cross-section taken along the lengthwise direction thereof, a rate of single fibers contained in a region at which adjacent divided fiber bundles are joined by a not-separation-processed part is 67% or less relative to the total single fibers in the width-direction cross-section.