ETFE Cable Ties for Spacecraft Static Dissipation
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Solution Overview
Problem
ETFE-based cable ties exhibit high electrical resistivity and low tensile strength, leading to potential electrical charging and catastrophic discharges in extraterrestrial environments, such as spacecraft, due to their high volumetric and surface electrical resistivity.
Innovation Solution
The method involves processing ETFE resin through repeated heating and cooling cycles within specific temperature ranges and irradiation to reduce electrical resistivity and increase tensile strength, thereby enhancing the material's conductivity and mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If ETFE resin is used for cable ties, then corrosion resistance and strength over wide temperature range are improved, but electrical resistivity increases leading to static build-up
Solution Approach 1:
The patent applies parameter changes by modifying the electrical resistivity parameter of ETFE resin through the addition of conductive fillers (carbon black, metal particles, or conductive polymers) and through thermal processing cycles. These changes transform the material from highly resistive to having controlled, reduced resistivity suitable for space applications while preserving the base ETFE's mechanical strength and temperature resistance.
Solution Approach 2:
The patent creates composite materials by combining ETFE resin with conductive additives such as carbon black, metal particles, or conductive polymers. This composite approach maintains the excellent mechanical and thermal properties of ETFE while introducing electrical conductivity to prevent static build-up, directly resolving the contradiction between strength and electrical resistivity.
2Reliability
If carbon black or additives are added to ETFE resin, then static dissipation is improved, but manufacturing complexity increases
Solution Approach 1:
The patent merges the conductive additive incorporation step with the existing extrusion manufacturing process. By integrating filler addition and thermal processing into the standard extrusion line, the patent achieves static dissipation improvement without requiring separate manufacturing operations, thus minimizing the increase in manufacturing complexity.
Solution Approach 2:
The patent employs self-service by utilizing the extrusion process itself to achieve both shaping and functional modification. The thermal processing during extrusion simultaneously completes the forming operation and activates the conductive properties through controlled heating and cooling cycles, eliminating the need for separate treatment steps.
3Reliability
If repeated heating and cooling cycles are applied, then electrical resistivity is reduced and tensile strength is increased, but processing time increases
Solution Approach 1:
The patent applies continuity of useful action by performing the thermal processing during the continuous extrusion operation. The heating and cooling cycles are integrated into the extrusion process flow, allowing the material to undergo multiple thermal cycles without interrupting production, thus minimizing the time penalty while achieving the desired electrical and mechanical property improvements.
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 processing method significantly reduces electrical resistivity and increases tensile strength, making ETFE-based articles more suitable for applications in environments prone to electrical charging, such as extraterrestrial settings, by improving their conductivity and mechanical toughness.
Implementation Method 1
An article formed of a static dissipative ETFE resin may be processed with repeated heating and cooling cycles, such as to reduce an electrical resistivity and/or to increase a tensile strength of the article
Implementation Method 2
An ETFE-based article may be irradiated to within a range of approximately 5 mega rads (Mrads) to 10 Mrads, inclusively, wherein a rad is a measurement of radiation equal to 10 milligrays of radiation
Data Source
AI summary
An article, such as, but not limited to, a cable strap to wrap, support, or secure one or more wires or cables, is formed by cyclically heating and cooling and/or irradiating an article formed of a static dissipative ethylene tetrafluoroethylen (ETFE) resin, to reduce an electrical resistivity and/or to increase a tensile strength of the article.