Thermoplastic Composite Welding With Flexible Pressure Membranes
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Solution Overview
Problem
Existing methods for thermally joining thermoplastic fiber composite components often face challenges such as porosity formation due to the tendency of fiber layers to open up during matrix softening, and require complex and rigid clamping forms that are difficult to apply evenly, especially in hard-to-reach areas like aircraft assembly.
Innovation Solution
A method using a partially flexible pressure application arrangement to maintain constant pressure on the joining zone until solidification, allowing for homogeneous pressing of the components and preventing air infiltration, which eliminates the need for fixed clamping forms and ensures even pressure distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If fixed clamping/pressing molds made of metal are used, then the components can be precisely replicated and pressed together, but the device complexity increases and it becomes difficult to apply evenly in hard-to-reach areas
Solution Approach 1:
The patent employs a flexible pressing membrane instead of rigid metal molds. This membrane can be easily positioned and applied even in hard-to-reach areas, while still providing uniform pressure distribution across the welding area. The flexibility of the membrane eliminates the complexity of designing and positioning rigid clamping forms for various component geometries.
2Productivity
If pressure is applied only during welding, then the welding process can be completed, but porosity forms due to fiber layer separation during matrix softening
Solution Approach 1:
The patent applies pressure to the thermoplastic fiber composite components before heating begins. This preliminary pressure prevents fiber layer separation as the matrix softens during welding, eliminating the root cause of porosity formation. By preparing the components in advance with proper pressure, the welding process can proceed rapidly without compromising joint quality.
3Stress or pressure
If a rigid pressure application arrangement is used, then pressure can be applied to the joining zone, but it cannot be applied evenly in hard-to-reach areas
Solution Approach 1:
The flexible pressing membrane can conform to complex component geometries and reach areas that rigid fixtures cannot access. This flexibility allows uniform pressure application across the entire welding area, including hard-to-reach zones, while maintaining simple and easy operation.
4Reliability
If the welding head remains at the weld point until solidification, then contact pressure is maintained, but the device complexity increases
Solution Approach 1:
The patent combines the pressure application function and welding function into a single integrated pressing and welding device. The flexible membrane serves both to apply pressure during welding and to maintain pressure during solidification, eliminating the need for separate clamping mechanisms and reducing overall device complexity.
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 effectively prevents porosity formation and allows for reliable thermal joining of thermoplastic fiber composite components with improved handling and reduced complexity in difficult-to-access areas, maintaining pressure until the matrix solidifies.
Implementation Method 1
applying pressure to the thermoplastic fiber composite components to be joined over a surface area with the pressure application arrangement, so that the fiber composite components are pressed together
Implementation Method 2
welding the fiber composite components in the joining zone during the pressure application
Implementation Method 3
maintaining the pressure application with the pressure application arrangement until the joining zone solidifies
Data Source
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AI summary
The present invention provides a method for the thermal joining of thermoplastic fiber composite components, comprising the following process steps: jointly covering the thermoplastic fiber composite components to be joined, at least in the area of a joining zone, with a pressure application arrangement that is at least partially flexible; applying pressure to the thermoplastic fiber composite components to be joined over a surface area with the pressure application arrangement, so that the fiber composite components are pressed together, at least in the joining zone; welding the fiber composite components in the joining zone during the pressure application; and maintaining the pressure application with the pressure application arrangement until the joining zone solidifies.Furthermore, the present invention provides a cover, in particular a mold or membrane, for a pressurizing device for thermally joining thermoplastic fiber composite components, as well as a device for thermally joining thermoplastic fiber composite components.