Multifilament Yarn Assembly with Transverse Stitch-Bonding

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Solution Overview

Problem

The existing methods for producing fiber-reinforced composite components using multifilament yarns face issues due to the lack of transverse rigidity, leading to displacement of yarns during resin injection, incomplete impregnation, and surface quality defects.

Innovation Solution

A method involving the planar arrangement of multifilament yarns with reinforcing threads inserted transversely using a stitch-bonding process, creating a defined distance between yarns to allow resin penetration and preventing yarn displacement, with a binder resin applied to fix the arrangement and prevent fraying.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If multifilament yarns are used without reinforcing threads, then the processing is simpler, but the transverse stiffness is insufficient causing yarn displacement during resin injection

Engineering Contradiction:
Improveprocessing simplicityVSAvoidtransverse stiffness
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The patent combines multifilament yarns with heat-fixable reinforcing threads to create a composite structure. The reinforcing threads are integrated into the yarn assembly at regular intervals, providing transverse stiffness while maintaining the flexibility and processability of the original multifilament yarns. This composite approach resolves the contradiction by adding structural support without significantly complicating the manufacturing process.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

Instead of making the entire yarn structure rigid, the patent applies reinforcing threads only at specific intervals along the yarn length. This localized reinforcement provides the necessary transverse stiffness at critical points while leaving other sections flexible for processing. The heat-fixable nature of the reinforcing threads allows them to be activated only when needed, maintaining ease of manufacture while improving strength where required.

Inventive Principle:
Principle #3Local quality

2Ease of operation

If multifilament yarns lack transverse stiffness, then the yarns are more flexible and easier to handle, but resin cannot penetrate properly and dry spots occur

Engineering Contradiction:
Improveyarn flexibilityVSAvoidresin penetration uniformity
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The integration of heat-fixable reinforcing threads creates a composite yarn structure that exhibits both flexibility and controlled rigidity. The reinforcing threads maintain the yarn's ability to be handled and positioned easily while providing sufficient transverse stiffness to prevent yarn collapse and maintain flow channels open for resin penetration, thereby eliminating dry spots.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The heat-fixable reinforcing threads provide dynamic properties to the yarn assembly. During processing, the threads remain flexible and can be positioned as needed. Once activated through heating, they provide rigid structural support to maintain flow channel geometry. This dynamic transition allows the yarn to adapt to processing requirements while ensuring proper resin penetration.

Inventive Principle:
Principle #15Dynamics

3Productivity

If no reinforcing threads are added, then the production process is faster and simpler, but the surface finish quality deteriorates due to filament displacement

Engineering Contradiction:
Improveproduction speedVSAvoidsurface finish quality
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The composite structure of multifilament yarns with integrated heat-fixable reinforcing threads prevents filament displacement during resin injection. The reinforcing threads act as internal supports that hold the multifilament structure together, ensuring that filaments remain in their intended positions and produce a high-quality surface finish without compromising production efficiency.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The heat-fixable reinforcing threads are pre-integrated into the yarn assembly before resin injection. This preliminary structuring ensures that the yarn maintains its geometric integrity throughout the processing sequence, preventing filament displacement and surface defects without requiring additional corrective steps during or after resin injection.

Inventive Principle:
Principle #10Preliminary action

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 ensures uniform resin impregnation, prevents dry spots, and maintains a smooth surface quality by creating flow channels between yarns, enhancing the structural integrity and finish of the composite components.

Implementation Method 1

a binder resin is applied to the fiber tape arrangement

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 2

insertion of a reinforcing thread and heat-fixable weft thread in the longitudinal direction of the elongated multifilament yarns at the edge of the multifilament yarns

Methodology Applied
Scientific EffectHeat treatment: Heat Treatment

Data Source

PatentEP3341515B1Method for producing a fiber band assembly having a plurality of multi-filament yarns arranged largely parallel to each other
Publication Date: 2021.10.27 BAYERISCHE MOTOREN WERKE AG
  • EP3341515B1 patent drawingFigure 1
  • EP3341515B1 patent drawingFigure 2~3

AI summary

The invention relates to a method for producing a fiber band assembly (8) having at least two multi-filament yarns (1) arranged largely parallel to each other, which method has the following steps: arranging the multi-filament yarns (1) in a planar manner in an elongate position in which the multi-filament yarns are adjacent and largely parallel to each other, with a distance (3) between the multi-filament yarns (1); inserting reinforcing means largely transversely to the longitudinal direction of the multi-filament yarns (1) with a distance between the reinforcing means in the longitudinal direction of the multi-filament yarns (1).