Speckled Fastener Coating for Lubricity and Electrical Dispersion
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Solution Overview
Problem
Fasteners used in the aerospace industry face challenges in balancing structural strength and electrical energy dispersion, as coatings that enhance lubricity for easier installation can electrically insulate the fasteners, while metal sleeves for energy dissipation are costly and inefficient.
Innovation Solution
Applying a speckled or spattered metal pigmentation coating on fasteners, which provides high lubricity without compromising electrical conductivity, ensuring efficient energy dispersion by exposing bare metal regions for continuous 360-degree conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a coating is applied to enhance lubricity, then installation force is reduced, but electrical conductivity is compromised
Solution Approach 1:
The fastener surface is treated with a lubricious coating only in specific regions where it contacts the composite structure during installation, while leaving other regions exposed to maintain electrical conductivity. This spatial differentiation of surface properties allows simultaneous achievement of low installation force and adequate electrical dispersion.
Solution Approach 2:
The fastener surface is divided into distinct zones: coated regions for lubricity and uncoated regions for electrical conductivity. This segmentation enables each region to perform its specific function without interfering with the other, resolving the contradiction between reducing installation force and maintaining electrical properties.
2Reliability
If a protective metal sleeve is used, then electrical energy dissipation is improved, but cost increases
Solution Approach 1:
Instead of applying a continuous metal sleeve around the entire fastener, the invention applies conductive properties only in specific locations where electrical energy dissipation is needed. This localized approach maintains adequate electrical dispersion while significantly reducing material costs and manufacturing complexity compared to full metal sleeving.
Solution Approach 2:
The invention uses a cost-effective coating application method that provides the necessary electrical conductivity without requiring expensive metal sleeves. The coating process is simpler and more economical than manufacturing and installing metal protective sleeves, achieving the same functional outcome at lower cost.
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 solution reduces installation force while maintaining structural integrity and effective electrical energy dissipation, offering a cost-effective alternative to metal sleeves by ensuring that electrical energy is safely dispersed without arcing.
Implementation Method 1
a coating that enhances lubricity without substantially compromising electrical conductivity of the fastener
Implementation Method 2
remaining exposed regions not covered by the coating provide desired levels of electrical energy dispersion at the fastener surface
Data Source
AI summary
Systems and methods are provided for fabricating fasteners. One embodiment is an apparatus that includes a fastener. The fastener includes a head, a cylindrical shank that extends from the head and is dimensioned to engage in a fit with a corresponding hole, and a coating that is discontinuously speckled around a circumference of the shank and extends axially along the shank, leaving irregular portions of a surface of the shank exposed. The coating exhibits a higher lubricity than the surface, and the coating exhibits a higher dielectric withstand voltage than the surface.