Fibre Composite Impregnation via Web Segmentation
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Solution Overview
Problem
Existing methods for impregnating fibre bundles with a melt suffer from high take-off forces and fibre damage due to high viscosity and velocity, limiting the quality and range of fibre types that can be processed effectively.
Innovation Solution
A process involving the drawing of fibre bundles into an impregnation chamber where they are expanded into multiple spatially separate webs, with melt introduction between the webs, followed by convergence and passage through a take-off die for shaping, allowing for high-quality impregnation across a wide viscosity range without fibre damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If fibre bundles are drawn through heated spreader bars to spread the rovings, then the fibre bundle is expanded and melt impregnation is achieved, but the take-off forces increase greatly with viscosity and velocity, causing fibre damage and limiting the process to low viscosities (up to 30 Pas) and low velocities (below 0.3 m/min)
Solution Approach 1:
The fibre bundle is divided into multiple separate fibre webs (typically 2-4 webs) that are processed independently through the impregnation chamber. This segmentation reduces the take-off force required for each individual web while maintaining effective impregnation, as each web experiences lower friction and drag forces compared to a single thick bundle.
Solution Approach 2:
The fibre bundle is expanded in the transverse direction to create multiple spatially separated webs with increased surface area. This dimensional transformation from a compact bundle to expanded webs allows melt introduction from multiple directions (above and below each web), improving impregnation quality while reducing the force required for take-off.
2Productivity
If the take-off velocity is increased to improve productivity, then the production rate increases, but the take-off forces increase and fibre damage occurs, and impregnation quality decreases
Solution Approach 1:
By dividing the fibre bundle into multiple thinner webs, the process can operate at higher take-off velocities without excessive take-off forces. Each individual web experiences reduced friction and drag, allowing velocities above 0.3 m/min while maintaining impregnation quality.
Solution Approach 2:
The expanded web structure acts as an intermediary that distributes the melt more effectively across the fibre surface at higher velocities. The increased surface area and spatial separation of webs allow the melt to penetrate and impregnate fibres even at elevated take-off speeds where conventional single-bundle methods would fail.
3Manufacturing precision
If multiple spreader devices are used to expand the fibre bundle, then the impregnation quality improves, but the mechanical friction on the bars increases and fibre damage occurs
Solution Approach 1:
The fibre bundle is segmented into multiple webs that pass through the impregnation chamber with reduced friction. Each individual web experiences lower contact friction compared to a thick bundle, reducing mechanical damage while still achieving good impregnation through the distributed web structure.
Solution Approach 2:
The process parameters (take-off velocity, melt viscosity, web spacing) are optimized for the expanded web configuration. By changing the structural parameter from a compact bundle to expanded webs, the friction characteristics are improved, allowing effective impregnation with reduced fibre damage.
4Manufacturing precision
If very low process velocities are used to achieve effective impregnation with low matrix viscosity, then impregnation quality improves, but productivity decreases
Solution Approach 1:
The fibre bundle is divided into multiple thinner webs, which can be processed at higher velocities while maintaining impregnation quality. The reduced thickness of each web allows faster throughput without sacrificing penetration effectiveness.
Solution Approach 2:
By expanding the fibre bundle into multiple spatially separated webs, the impregnation process occurs more efficiently. The increased surface area and reduced web thickness allow effective impregnation at higher velocities, improving productivity while maintaining quality.
5Manufacturing precision
If a large number of deflection points are used to mitigate high viscosity effects, then impregnation effectiveness improves, but fibre damage increases and process velocity decreases
Solution Approach 1:
The fibre bundle is segmented into multiple webs that require fewer deflection points to achieve effective impregnation. Each individual web can be impregnated with fewer bends and direction changes, reducing fibre damage while maintaining effectiveness.
Solution Approach 2:
The expanded web structure serves as an intermediary that facilitates melt penetration with reduced need for deflection points. The increased surface area and spatial separation of webs allow the melt to access fibres more directly, reducing the number of bends required and minimizing fibre damage.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This process achieves robust individual-fibre impregnation with high take-off velocity and short residence time, ensuring excellent impregnation quality and minimizing fibre damage, even with high-viscosity systems, by using a combination of wetting and impregnation steps.
Implementation Method 1
one or more fibre bundle(s) is/are drawn by way of one or more spreader device(s) into an impregnation chamber in such a way as to give at least two mutually superposed, spatially separate and spread fibre webs
Implementation Method 2
melt is introduced by way of horizontally oriented distributor bars, in each case arranged between two fibre webs
Implementation Method 3
the individual fibre webs are caused to converge in such a way that they are mutually superposed and contact one another
Implementation Method 4
after the fibre webs have converged they are drawn, at the end of the operating unit, through a take-off die where the first shaping takes place
Data Source
AI summary
By use of a process for the production of a fibre-composite material, comprising the following steps:a) one or more fibre bundle(s) is/are drawn by way of one or more spreader device(s) into an impregnation chamber in such a way as to give at least two mutually superposed, spatially separate and spread fibre webs;b) melt is introduced by way of horizontally oriented distributor bars, in each case arranged between two fibre webs;c) the individual fibre webs are caused to converge in such a way that they are mutually superposed and contact one another;d) after the fibre webs have converged they are drawn, at the end of the operating unit, through a take-off die where the first shaping takes place,and also by use of a corresponding device, very good impregnation quality is achieved through a specific wetting method implemented after a high degree of expanding, and also through subsequent relative longitudinal and transverse movements of the individual fibres.