Thermoplastic Composite Cavity Flow for Uniform Reinforcement

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Solution Overview

Problem

The production of fiber-reinforced plastic composites with complex functional structures, such as ribs, often results in mechanical weak points at the transition areas due to inhomogeneous fiber reinforcement, leading to reduced stressability and load-bearing capacity, and requires complex and costly tooling for injection molding.

Innovation Solution

A method involving a semi-finished textile product with thermoplastic and reinforcing fibers is inserted into a pressing tool where the thermoplastic fibers melt and flow into cavities, embedding reinforcing fibers to form a continuous matrix, eliminating the need for separate injection molding and ensuring uniform fiber reinforcement throughout the component.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If injection molding is used to produce functional structures on fiber-reinforced composites, then complex shapes can be achieved, but mechanical weak points are created at the interface due to inhomogeneous fiber reinforcement

Engineering Contradiction:
Improvecomplex functional structuresVSAvoidinterface strength
Core Design Contradiction:
ShapeVSStrength

Solution Approach 1:

The patent combines the flat component forming and functional structure creation into a single consolidation process. The textile semi-finished product with pre-positioned fibers is consolidated in one operation, eliminating the interface between separately molded parts and ensuring continuous fiber reinforcement throughout the entire component including functional structures like ribs.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The reinforcing fibers are pre-positioned in the textile semi-finished product before consolidation. This preliminary arrangement ensures that fibers are correctly positioned to provide continuous reinforcement through functional structures before the forming process begins, avoiding the need for subsequent injection molding that would create weak interfaces.

Inventive Principle:
Principle #10Preliminary action

2Adaptability or versatility

If separate injection molding is used for functional structures, then additional design freedom is achieved, but device complexity and cost increase due to complex tooling requirements

Engineering Contradiction:
Improvedesign freedomVSAvoidtooling complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges the flat component forming and functional structure creation into a single consolidation process using a single tool. The cavity structure in the tool allows both the flat component and functional structures to be formed simultaneously, eliminating the need for separate injection molding operations and complex multi-stage tooling.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The consolidation tool is designed with cavities that can form both flat components and functional structures like ribs in a single operation. This multi-functional tool replaces the need for separate injection molding tools, reducing device complexity while maintaining design freedom for creating complex geometries.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Ease of manufacture

If conventional consolidation processes are used, then manufacturing simplicity is maintained, but fiber arrangement distortion occurs in large areas leading to unsatisfactory mechanical properties

Engineering Contradiction:
Improveprocess simplicityVSAvoidfiber arrangement precision
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The textile semi-finished product is pre-manufactured with reinforcing fibers and thermoplastic fibers in their final desired arrangement. This preliminary structuring prevents fiber distortion during consolidation because the fibers are already positioned correctly before the forming process begins, maintaining both manufacturing simplicity and fiber arrangement precision.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses thermoplastic fibers that change phase from solid to molten state during consolidation. This parameter change allows the material to flow and conform to the tool cavity while maintaining fiber positioning, enabling large area components to be formed without fiber arrangement distortion while keeping the process simple.

Inventive Principle:
Principle #35Parameter changes

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 method produces fiber-reinforced plastic composites with enhanced mechanical properties by ensuring continuous fiber reinforcement in both flat and functional structures, reducing the risk of delamination and improving load-bearing capacity without the need for complex tooling.

Implementation Method 1

The textile semi-finished product is heated in the pressing tool above the melting temperature or melting temperature range of the thermoplastic fibers. This causes the thermoplastic fibers to melt, and the first and/or the second pressing part is advanced in such a way that the thermoplastic begins to flow

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 2

The textile semi-finished product is then consolidated in the press tool by cooling it below the solidification temperature of the thermoplastic

Methodology Applied
Scientific EffectSolidification: Freezing

Data Source

PatentEP3599084B1Method for producing a synthetic fibre composite
Publication Date: 2023.08.23 TECHNISCHE UNIVERSITAT DRESDEN

AI summary

The invention relates to a method for producing a fiber-reinforced plastic composite (25), comprising at least the following steps: at least one planar textile semi-finished product (20), which contains at least reinforcing fibers (21) and thermoplastic fibers (22), is placed in the interior (10) of a press tool (1), wherein said interior (10) is bounded by surfaces (5, 15) of at least one first press part (2) and a second press part (12) of the press tool (1), and wherein at least one cavity (14) is formed in at least one of said surfaces (5, 15), which is not filled by the inserted at least one textile semi-finished product (20); the textile semi-finished product (20) is heated in the press tool (1) above the melting temperature or melting temperature range of the thermoplastic fibers (22), and pressure is exerted on the textile semi-finished product (20) by the press tool (1), causing the thermoplastic fibers (22) to melt.wherein the first and/or the second pressing part (2, 12) are advanced such that molten thermoplastic penetrates the at least one cavity (14), carrying reinforcing fibers (21) with it during this movement, so that a thermoplastic matrix (22a) and reinforcing fibers (21) are now present in the at least one cavity (14), the textile semi-finished product (20) is consolidated in the pressing tool (1) by cooling the textile semi-finished product (20) below the solidification temperature of the thermoplastic, and the textile semi-finished product (20) is removed from the pressing tool (1) as a fiber-reinforced plastic composite (25).