3D Fiber Preform Forming with Binder Activation and Vacuum Shaping
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Solution Overview
Problem
Current methods face challenges in producing complexly shaped three-dimensional preforms from reinforcing fibers, particularly those with a T-shaped profile cross section, using nonwoven fibrous sheets in a continuous forming process, as existing techniques lack efficiency and automation for industrial-scale fabrication.
Innovation Solution
A method involving a draping mold with a complex geometrical shape, where reinforcing fibers with a binder are formed using a displaceable forming element, an airtight film is applied, and negative pressure is created to maintain the shape, followed by binder activation and curing, allowing for the production of complex preforms with improved handling and structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If nonwoven fibrous sheets are used to produce three-dimensional preforms, then productivity and automation are improved, but manufacturing precision and shape complexity are worsened
Solution Approach 1:
The method applies a binder to the reinforcing fibers before forming, which is then activated during the forming process to provide temporary holding power. This preliminary bonding action enables nonwoven sheets to be formed into complex three-dimensional shapes with high precision while maintaining industrial-scale productivity, as the binder temporarily secures fibers in their desired positions during automation processes.
Solution Approach 2:
The invention utilizes temperature changes to activate the binder material. The binder is applied in an inactive state to allow fiber movement and positioning, then activated through heating to melt and bond the fibers together. This parameter change enables the transition from a manipulable fiber state to a fixed preform structure, resolving the contradiction between ease of forming and shape retention.
2Shape
If complex geometrical draping molds are used, then preform shape complexity is improved, but device complexity increases
Solution Approach 1:
The invention uses a flexible forming element that can be displaced along the draping mold to form complex geometries. This flexible approach allows the mold to accommodate complex preform shapes without requiring equally complex rigid mold structures. The forming element adapts to the mold's geometry while maintaining simplicity in its own design, enabling complex preform production with relatively simple device architecture.
3Reliability
If intrinsic stability of fiber preforms is increased, then reliability for vacuum infusion is improved, but ease of forming is worsened
Solution Approach 1:
The binder is applied to the fibers in advance but remains inactive during the forming process, allowing the fibers to be easily manipulated and formed into complex shapes. After forming is complete, the binder is activated through heating to provide the necessary structural stability and intrinsic holding power for subsequent vacuum infusion processes. This temporal separation of forming and stabilization enables both ease of manufacture and reliability.
Solution Approach 2:
The invention exploits temperature as a control parameter to switch the binder between inactive and active states. During forming, the binder remains inactive to allow easy manipulation. After forming, heating activates the binder to provide the required structural stability. This parameter-based state transition resolves the contradiction between formability and structural integrity.
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 enables the efficient and automated production of complex three-dimensional preforms, particularly those with T-shaped profiles, using nonwoven fibers, enhancing industrial scalability and precision in fiber arrangement and shape retention.
Implementation Method 1
creating a negative pressure in the intermediate space between the airtight film and the draping mold
Implementation Method 2
activating the binder and removing the negative pressure after curing of the binder
Data Source
AI summary
A method for producing a three-dimensional preform from reinforcing fibers for producing a component from a fiber-reinforced plastic comprises the steps of introducing at least one layer of fibers having a binder into a draping mold, forming the at least one layer of fibers by at least one forming element which is displaceable along the draping mold, applying an airtight film to the at least one layer of fibers during or directly after the forming, creating a negative pressure in the intermediate space between the airtight film and the draping mold, activating the binder and removing the negative pressure after curing of the binder.