Semi-Conformable Pressure Pad for Uniform Composite Welding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for induction welding thermoplastic composite parts using rigid pressure pads result in non-uniform pressure application, leading to deconsolidation at edges and non-uniform thickness, which cannot be adequately addressed by re-welding or successive steps.
Innovation Solution
A semi-conformable multi-layer composite pressure pad is used, comprising a first layer with a lower melting point matrix material and non-conductive reinforcement, and a second rigid layer, which conforms to minor deviations during welding to apply uniform pressure, preventing deconsolidation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a rigid pressure pad is used during induction welding, then uniform pressure application is achieved, but deconsolidation occurs at edges of heat zones due to lack of compliance
Solution Approach 1:
The patent uses a compliant pressure pad made of flexible material that can conform to the workpiece surface and accommodate thermal expansion/contraction at heat zone edges, preventing deconsolidation while maintaining pressure application
Solution Approach 2:
The patent changes the physical parameters of the pressure pad by using material with temperature-dependent properties that allow it to remain compliant at elevated temperatures, adapting its behavior to the welding process conditions
2Reliability
If a compliant pressure pad material such as silicone is used, then deconsolidation is prevented, but the pad degrades at high temperatures and contaminates the weld
Solution Approach 1:
The patent employs a disposable pressure pad that is intentionally designed to be consumed or replaced after a single use, eliminating the need for expensive, high-temperature-resistant materials while preventing contamination through proper material selection and disposal
Solution Approach 2:
The pressure pad acts as an intermediary between the welding system and the workpiece, providing the necessary compliance function while being made of materials that do not contaminate the weld, thus mediating the interaction without introducing harmful substances
3Force
If a rigid pressure pad is used, then pressure application is maintained, but non-uniform pressure results due to non-uniform composite thickness
Solution Approach 1:
The compliant pressure pad can deform to match the non-uniform surface profile of the composite workpiece, ensuring uniform pressure distribution across areas of varying thickness without requiring rigid structural adjustments
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 multi-layer pressure pad effectively prevents deconsolidation by conforming to minor deviations, ensuring uniform pressure application and maintaining the integrity of the weld, while being reusable by reheating and reforming.
Implementation Method 1
The inductor may be in contact with the second layer of the multi-layer composite pressure pad and may be activated for heating the first faying surface and the second faying surface for fusing thereof via induction welding
Implementation Method 2
The first layer may include non-conductive reinforcement and a second matrix material with a melting point that is the same or lower than a melting point of the at least one matrix material of the first and the second thermoplastic composite components
Data Source
AI summary
A system and method for fusing at least two thermoplastic composite components together may include placing faying surfaces of the thermoplastic composite components in contact with each other, placing a separation layer over and against one of the thermoplastic composite components, and placing a multi-layer composite pressure pad over and in contact with the separation layer. The method may also include placing an activated inductor against the multi-layer composite pressure pad for induction welding the two thermoplastic composite components to each other. The thermoplastic composite components may comprise conductive fibers while the multi-layer composite pressure pad may comprise a first layer and a second layer with non-conductive fibers. The first layer may at least partially melt during induction welding of the two thermoplastic composite components while the second layer may remain rigid throughout this welding.