Needled Composite Preforms for Thick Ply Cohesion and Resin Flow
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Solution Overview
Problem
Existing methods for producing polymer matrix composite parts face challenges with high manufacturing costs, scrap rates, and insufficient permeability and cohesion in dry preforms, particularly during high-pressure and high-temperature resin transfer molding, which affect the efficiency and quality of the final product.
Innovation Solution
A method involving multiple needle-punching steps to create preforms with significant thickness and cohesion, using unidirectional continuous fibers and non-woven filaments, with optional lubrication to reduce friction and enhance permeability, followed by impregnation with a polymer matrix.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If dry preforms are made manually from prefabricated fabrics, then manufacturing cost is high and scrap rates are significant, but automation and waste reduction are achieved by producing dry preforms by automatically draping continuous unidirectional fibers
Solution Approach 1:
The patent applies needle-punching technology to create a porous nonwoven layer that maintains high permeability while providing cohesion. The needle-punched preform exhibits excellent permeability allowing rapid impregnation and excellent cohesion between fibers, resolving the contradiction between automation and preform quality.
Solution Approach 2:
The patent combines automatically draped continuous unidirectional fibers with a needle-punched nonwoven layer to create a composite preform structure. This composite approach provides both the automation benefits of fiber draping and the cohesion benefits of needle-punching, while maintaining high permeability for impregnation.
2Extent of automation
If automatically draped preforms are produced with superimposed plies, then automation is achieved, but permeability and cohesion are insufficient for rapid impregnation at high pressure and temperature
Solution Approach 1:
The patent merges automatically draped continuous fibers with a needle-punched nonwoven layer in a single integrated preform structure. This combination allows the preform to benefit from both automation (draping) and enhanced permeability-cohesion properties (needle-punching), enabling rapid impregnation at high pressure and temperature.
Solution Approach 2:
The needle-punched nonwoven layer creates a porous structure that maintains high permeability even under high pressure and temperature conditions during RTM injection, while simultaneously providing the cohesion needed for structural integrity during automated processing.
3Device complexity
If preforms are made with significant thickness and multiple folds, then structural complexity is reduced, but obtaining adequate cohesion becomes difficult
Solution Approach 1:
The needle-punched nonwoven layer acts as an intermediary binding medium between the continuous unidirectional fiber plies. This intermediary layer provides cohesion throughout the thickness of the preform, enabling the production of thick multi-plied structures without delamination while maintaining structural simplicity.
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
The process improves the cohesion and permeability of preforms, allowing for efficient impregnation at high speeds without delamination, reducing waste and lowering production costs while maintaining mechanical integrity.
Implementation Method 1
the needles are driven back and forth by a drive system of the needle-punching device, passing through the ply subsets... at least some of the filaments become lodged in the needle slots and are carried by the needles through the ply subset
Implementation Method 2
The needle-punching of filaments through the continuous fibers of a subset of plies is carried out in the presence of a lubricant, also called a lubricating agent, to reduce friction between the needles and the continuous fibers
Implementation Method 3
a processing step comprising impregnating the dry needle-punched preform with an impregnation polymer forming the polymer matrix
Implementation Method 4
impregnating the dry preform with an impregnation polymer, for example by injection and/or infusion
Data Source
Figure 1A~3
Figure 4~6
AI summary
The present invention relates to a method for producing a part made of a composite material, comprising a step of producing a needled preform (105) which comprises at least two needled sub-sets (103a) of plies stacked one on top of the other, each needled sub-set of plies being obtained by needling non-woven filaments applied to at least a first main face of a sub-set of superimposed plies (101a), wherein each ply is formed of continuous fibres, the needling being performed by a needling device (7) comprising a plurality of needles (71), each needle being provided with a notch, such that filaments are carried by the needles and arranged in a direction that is substantially perpendicular to the continuous fibres of the sub-set of plies, and a step of treating the needled preform to form the polymer matrix of the part made of composite material.