Multi-Layer Coated Wire for Aerospace Abrasion Resistance
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Solution Overview
Problem
Aerospace wiring lacks sufficient resistance to abrasion, cut-through, and sealing at elevated temperatures, and existing coatings can damage certain conductor materials, while also compromising markability and durability.
Innovation Solution
A coated wire with a multi-layer coating consisting of ETFE, PAEK, and ETFE layers, applied through a seamless extrusion process, providing enhanced durability, resistance, and markability, and allowing the use of tin-coated conductors by controlling extrusion temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a single-layer ETFE coating is used, then the wire provides good chemical resistance and arc resistance, but it has insufficient resistance to abrasion and cut-through at elevated temperatures
Solution Approach 1:
The patent applies composite materials by combining ETFE and PTFE layers in a multi-layer coating structure. The ETFE layer provides chemical resistance and arc resistance, while the PTFE layer enhances abrasion and cut-through resistance, creating a composite coating that achieves superior overall performance compared to single-layer coatings.
Solution Approach 2:
The patent segments the coating into multiple functional layers with distinct thicknesses and material compositions. The inner ETFE layer (0.002-0.006 inch) provides baseline protection, while the outer PTFE layer (0.001-0.003 inch) specifically addresses wear resistance, allowing each layer to optimize its specialized function.
2Reliability
If composite tape wrap coating is used, then the wire provides good sealing, but the seams inherent in wrapping the tape reduce sealing effectiveness
Solution Approach 1:
The patent replaces the mechanical tape-wrapping system with a seamless extruded coating process. This substitution eliminates seams and joints by applying continuous layers of ETFE and PTFE materials through extrusion, providing uniform sealing without the structural weaknesses of wrapped tape configurations.
3Strength
If additional PTFE layer is added to composite tape wrap, then the wire provides improved wear resistance, but it results in tearing during installation and reduced markability
Solution Approach 1:
The patent optimizes the thickness parameters of the PTFE layer (0.001-0.003 inch) to achieve the right balance between wear resistance and flexibility. This parameter control prevents the coating from becoming too thick and brittle, which would cause tearing during installation, while still providing sufficient abrasion resistance.
Solution Approach 2:
The combination of ETFE and PTFE in specific thickness ratios creates a composite structure where the ETFE layer provides flexibility and markability, while the PTFE layer contributes wear resistance. This composite approach prevents tearing by distributing mechanical stresses across layers with complementary properties.
4Reliability
If heating is applied to improve sealing during installation, then the wire provides better sealing, but it damages certain conductor materials that may be damaged by such temperatures
Solution Approach 1:
The patent applies preliminary action by pre-forming the seamless coating layers during the extrusion process itself, rather than requiring post-installation heating to achieve sealing. The extrusion process creates immediate sealing at room temperature, eliminating the need for thermal treatment that could damage temperature-sensitive conductor materials.
Solution Approach 2:
The patent replaces thermal sealing methods with a mechanical extrusion process. The seamless coating is formed through controlled extrusion of molten or softened polymer materials that self-seal during the extrusion process, eliminating the need for subsequent heating operations that could harm the conductor.
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 coating significantly improves resistance to abrasion, cut-through, and sealing, while enabling the use of tin-coated conductors and maintaining markability, thus addressing the limitations of existing aerospace wiring.
Implementation Method 1
The three coating layers may each be continuous and seamless extruded layers in one configuration
Data Source
AI summary
A coated wire suitable for aerospace applications includes a metallic conductor elongated along an axis and having an outer surface extending along the axis, and three coating layers surrounding the conductor. A first coating layer is connected to the outer surface of the conductor and extends along the axis to surround the conductor, and the first coating layer is formed of ethene-tetrafluoroethene. A second coating layer is connected to the first coating layer and extends along the axis to surround the first coating layer, and the second coating layer is formed of polyaryletherketone. A third coating layer is connected to the second coating layer and extends along the axis to surround the third coating layer, wherein the third coating layer is formed of ethene-tetrafluoroethene. The three coating layers may each be continuous and seamless extruded layers in one configuration.