Continuous Fiber Preform Additive Manufacturing for Composite Parts

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Solution Overview

Problem

Current additive manufacturing technologies for fiber-reinforced composite parts face challenges in achieving complex geometries and mechanical properties due to porosity issues, limiting their performance compared to traditional methods.

Innovation Solution

The method involves using Fused Deposition Modeling (FDM) to create a continuous fiber preform with a bundle of fibers wrapped in a non-impregnating binder, which is then 3D deposited and subsequently impregnated with resin using liquid molding processes like Resin Transfer Molding (RTM), eliminating porosity and enabling complex geometries.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If additive manufacturing is used to directly fabricate final reinforced composite parts with short or continuous fibers, then automation and geometric flexibility are improved, but porosity increases and mechanical properties deteriorate

Engineering Contradiction:
Improveautomation of manufacturing processVSAvoidmechanical properties of composite parts
Core Design Contradiction:
Extent of automationVSReliability

Solution Approach 1:

The manufacturing process is divided into two distinct stages: first, additive manufacturing creates a preform structure with continuous fibers and controlled porosity; second, the preform is impregnated with resin to eliminate porosity and create the final composite part. This segmentation allows each stage to optimize for its specific function without compromising the other.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The preform is manufactured in advance with a specific porous structure designed to facilitate subsequent resin impregnation. The continuous fibers are arranged in the desired final geometry before resin addition, allowing the resin to flow through and saturate the structure, eliminating porosity and achieving high mechanical properties.

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If traditional fabric cutting and stacking is used to create preforms, then manufacturing precision is maintained, but geometric complexity is limited to 2D or 2D 1/2 pieces

Engineering Contradiction:
Improveprecision of preform fabricationVSAvoidgeometric complexity of preform
Core Design Contradiction:
Manufacturing precisionVSShape

Solution Approach 1:

The process transitions from 2D fabric cutting and stacking to 3D additive manufacturing, enabling the creation of preforms with complex three-dimensional geometries, variable thickness, and spatially varying fiber orientations that cannot be achieved with traditional planar methods.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The additive manufacturing process allows continuous variation of geometric parameters (thickness, orientation, density) throughout the preform volume, enabling complex 3D shapes while maintaining precise control over fiber placement and preform structure through digital modeling and controlled material deposition.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If pressure is applied during fiber deposition to compact the stack, then manufacturing precision is improved, but the ability to create complex 3D geometries is reduced

Engineering Contradiction:
Improvecompaction precision of fiber stackVSAvoidcomplexity of 3D preform geometry
Core Design Contradiction:
Manufacturing precisionVSShape

Solution Approach 1:

The process replaces mechanical compaction pressure with a chemical/biological binding mechanism. A binder material is deposited simultaneously with or after the continuous fibers, adhering them together to form the preform structure without requiring high compression pressures that would limit geometric complexity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 approach results in reinforced composite parts with improved mechanical properties and the ability to produce complex geometries not achievable with traditional methods, while reducing porosity and production costs.

Implementation Method 1

the extruder heating the continuous filament to a temperature which is between the softening temperature of the binder and the melting temperature of the binder

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 2

heating the continuous filament to a temperature which is between the softening temperature of the binder and the melting temperature of the binder

Methodology Applied
Scientific EffectSoftening: Melting

Implementation Method 3

impregnated with resin using liquid molding processes like Resin Transfer Molding (RTM)

Methodology Applied
Scientific EffectImpregnation: Absorption (physical)

Data Source

PatentEP3827967B1Method for additive manufacturing of a preform
Publication Date: 2024.06.12 FUNDACION TECNALIA RESEARCH & INNOVATION
  • EP3827967B1 patent drawingFigure 1~2
  • EP3827967B1 patent drawingFigure 3~4

AI summary

A method for additive manufacturing by Fused Deposition Modeling of a preform, is disclosed wherein the method comprises: a) supplying a continuous filament that comprises: (i) one inner core consisting of a bundle of fibers and (ii) an outer binder coating, which completely wraps said inner core; b) feeding the continuous filament to an extruder at a feed rate, the extruder heating the continuous filament to a temperature which is between the softening temperature of the binder and the melting temperature of the binder, and below the melting temperature of the fibers; and c) 3D deposition of the continuous filament on a base surface in at least one or more successive layers to obtain the preform. The obtained preform is also disclosed and a reinforced composite part obtained therefrom.