UD Layer Thickness Uniformity via Ribbon Width Control
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Solution Overview
Problem
Existing methods for producing unidirectional (UD) layers in fiber-reinforced plastics often result in uneven thickness due to the natural bell-shaped distribution of filament strands when spread into ribbons, leading to waviness in the final UD layer.
Innovation Solution
The method involves spreading filament strands into ribbons wider than the pitch width and then adjusting their thickness by pushing them together or overlapping them to achieve uniformity, using a device with separate spreading groups and calibration tools to ensure consistent width and prevent gaps or overlaps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If filament strands are spread out to form ribbons with natural bell-shaped distribution, then the spreading process is simple, but the UD layer exhibits waviness and non-uniform thickness
Solution Approach 1:
The patent applies local quality by creating different ribbon width configurations in different areas. Ribbons are arranged with varying widths such that wider ribbons compensate for thinner sections while narrower ribbons accommodate thicker sections, achieving uniform overall thickness. This is accomplished by controlling the spreading degree and positioning of individual ribbons to create a non-uniform local structure that produces a uniform global result.
2Manufacturing precision
If ribbons are spread out to greater width than pitch width, then thickness uniformity can be improved, but gaps or overlaps may occur between adjacent ribbons
Solution Approach 1:
The patent employs parameter changes by systematically varying the width parameters of adjacent ribbons. Rather than maintaining uniform ribbon widths, the method adjusts the width of each ribbon within a controlled range, creating a distribution where some ribbons are wider and others are narrower. This parameter variation allows ribbons to interlock and compensate for thickness variations without creating excessive gaps or overlaps.
3Strength
If multiple UD layers with different fiber directions are stacked to increase tensile strength, then structural performance improves, but manufacturing complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the fiber reinforcement into multiple discrete UD layers, each with optimized thickness uniformity. The improved thickness control in individual layers reduces the number of layers needed to achieve target mechanical properties, thereby simplifying the overall stacking and embedding process while maintaining or enhancing multi-directional tensile strength.
Data Source
Figure 1
Figure 2a~2c
AI summary
A method for producing a UD layer (2) of a predetermined layer width from a predetermined number of filament strands (5) is described, in which the filament strands (5) are spread transversely to the longitudinal direction of the UD layer (2) to form ribbons (16, 17) and arranged side by side. The aim is to produce a UD layer (2) with the most uniform thickness possible. For this purpose, the ribbons (16, 17) are spread to a width greater than a pitch width calculated by dividing the layer width by the number of filament strands (5).