Partially Separated Fiber Bundle for Flowable Composite Molding
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Solution Overview
Problem
Existing methods for producing fiber bundles with an optimal number of single fibers for composite material molding struggle with continuous separation without causing yarn breakage, limited adjustment range, and inefficient handling, especially with large tows and twisted fibers, leading to suboptimal mechanical properties and flowability.
Innovation Solution
A partially separated fiber bundle is created with alternating separation-processed and not-separation-processed sections, controlled by a separation means with projected parts that interlace fibers, allowing for continuous and stable slitting, and a method for producing this bundle that controls the ratio of single fibers in each section to achieve optimal distribution of thin and thick fibers, reducing the need for rotary blade exchange and improving handling.
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 invention divides the fiber bundle into multiple sub-bundles by introducing separation-processed sections where the fiber bundle is split into 2-10 sub-bundles. This segmentation allows the overall bundle to maintain sufficient thickness for mechanical strength while creating thinner effective reinforcement elements that improve flowability during molding. The separation is achieved through projected parts that penetrate and divide the bundle without complete separation throughout its entire length.
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 loses convergence property and becomes difficult to handle
Solution Approach 1:
Instead of applying separation uniformly along the entire fiber bundle length, the invention applies separation locally at specific sections. The separation-processed sections are alternated with non-separated sections, creating local variations in bundle structure. This local quality approach maintains convergence in non-separated regions while achieving fiber number adjustment in separated regions, thereby preserving handling properties.
3Ease of operation
If a separation cutter with longitudinal and lateral blades is used, then handling property is improved, but the entire blade must be exchanged when one blade reaches cutting life
Solution Approach 1:
The separation means is divided into multiple independent projected parts that can function independently. Each projected part acts as a separate cutting element that can be replaced individually. This segmentation of the separation means allows only the worn projected part to be exchanged rather than the entire blade assembly, reducing maintenance complexity and cost while maintaining the dual-function capability of the device.
4Ease of manufacture
If a roll with projections is used for partial separation, then separation is achieved, but it is impossible to control the lengths of separated and not-separated sections
Solution Approach 1:
The separation means is designed to move dynamically relative to the fiber bundle during the separation process. By controlling the movement distance, speed, and timing of the projected parts as they penetrate and withdraw from the fiber bundle, precise control over the lengths of separated and non-separated sections is achieved. This dynamic control mechanism allows for programmable section length specifications that static roll projections cannot provide.
Data Source
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Figure 3(A)~3(B)
AI summary
A partially separated fiber bundle that comprises 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. A production method for the partially separated fiber bundle, a fiber-reinforced resin molding material that uses the partially separated fiber bundle, and a production method for the fiber-reinforced resin molding material that uses the partially separated fiber bundle. When the partially separated fiber bundle has been made into an intermediate base material of fiber bundles of discontinuous fibers that is to be used in molding of a composite material, it is possible to control thin fiber bundles and thick fiber bundles at an optimal ratio and an optimal distribution state and to exhibit the flowability during molding and the mechanical properties of a molded article at a good balance.