Fiber Bundle Splitting With Rotary Blade Release Sections
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Solution Overview
Problem
Existing methods for splitting fiber bundles in a longitudinal direction are prone to fiber breakage and instability, leading to uneven distribution of split and non-split portions, which affects the production of high-quality fiber-reinforced resin molding materials.
Innovation Solution
A splitting machine with a rotary blade and a spacer member is used, where the rotary blade has a cut-off portion acting as a releasing section, and specific length and radius ratios are maintained to ensure stable splitting, allowing for longer split portions and shorter non-split portions, with a controlled wrap angle and speed ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a rotary blade is rotated and thrust through the fiber bundle to split it, then the fiber bundle is split into multiple bundles, but the fiber bundle may break and wrap around the roll when filaments skew or meander
Solution Approach 1:
The rotary blade is segmented into multiple cutting edges (e.g., 6 knives) arranged side by side along the circumferential direction, allowing simultaneous multiple-point contact with the fiber bundle. This segmentation distributes the splitting force across multiple locations, reducing stress concentration and preventing fiber breakage while maintaining high splitting efficiency.
Solution Approach 2:
The rotary blade performs periodic thrusting motions through the fiber bundle during rotation, creating alternating split and non-split portions. This periodic action allows the fiber bundle to be gradually separated without continuous high-force contact, reducing the risk of fiber breakage and wrapping while maintaining productive splitting.
2Manufacturing precision
If the split portion becomes longer to improve separation, then the fiber bundle is more likely to be twisted or broken and supply to the cutting machine becomes unstable
Solution Approach 1:
The segmented rotary blade with multiple circumferential knives creates multiple simultaneous split points, distributing the separation process across several locations. This prevents excessive localized splitting that would cause twisting and breakage, while still achieving sufficient separation between fiber bundles.
Solution Approach 2:
The rotary blade is designed to create alternating split and non-split portions along the fiber bundle length. This partial splitting approach provides just enough separation for downstream processing without over-splitting, which would cause instability and breakage. The non-split portions act as connectors maintaining bundle integrity.
3Reliability
If the non-split portion becomes longer to maintain fiber bundle stability, then the cut fiber bundle is not sufficiently separated
Solution Approach 1:
The segmented rotary blade structure with multiple circumferential cutting edges creates distributed split points along the fiber bundle. This segmentation allows for adequate separation of fiber bundles while keeping non-split portions short enough to maintain stability, resolving the trade-off between separation quality and bundle integrity.
Solution Approach 2:
The design parameters of the rotary blade (number of knives, their circumferential spacing, and thrust depth) are optimized to achieve the desired balance between split and non-split portion lengths. By adjusting these parameters, sufficient separation is achieved while maintaining fiber bundle stability for stable supply to the cutting machine.
4Productivity
If a conventional rotary blade is used without a cut-off portion, then the blade continuously thrusts through the fiber bundle, but this causes fiber breakage and wrapping around rolls
Solution Approach 1:
The rotary blade is segmented with a cut-off portion that divides the continuous blade into discrete cutting sections. This segmentation creates periodic engagement and disengagement zones, allowing the blade to thrust through the fiber bundle in controlled intervals rather than continuously, thereby preventing fiber breakage and wrapping while maintaining productive operation.
Solution Approach 2:
The cut-off portion extracts or removes a section from the continuous rotary blade, creating a releasing section. This extracted portion allows the blade to periodically withdraw from the fiber bundle during rotation, preventing continuous high-force contact that causes fiber damage, while the remaining blade portions continue to perform splitting functions.
Data Source
Figure 1
Figure 2A~2B
Figure 3~4
AI summary
What is provided is a method for stably producing a fiber-reinforced resin molding material by splitting a fiber bundle such that a split portion becomes long while a non-split portion is shortened. A method for producing a fiber-reinforced resin molding material in which a cut fiber bundle is impregnated with a resin, the method comprising a splitting step of splitting the fiber bundle with a splitting machine at intervals in a longitudinal direction and a cutting step of cutting the fiber bundle at intervals in the longitudinal direction after the splitting step, in which the splitting machine comprises a rotary blade having a releasing section and a spacer member adjacent to the rotary blade.