Speckled Fastener Shank Coating for Lubricity and Charge Dissipation
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Solution Overview
Problem
Fasteners in the aerospace industry face challenges in balancing structural strength and electrical conductivity, as coatings that enhance lubricity for easier installation can electrically insulate the fasteners, while metal sleeves provide conductivity but are costly and complex to implement.
Innovation Solution
Applying a non-uniform, discontinuous metal pigmentation or dry film lubricant coating to fasteners, which increases lubricity without compromising electrical conductivity, allowing for efficient energy dissipation by exposing bare metal regions that provide high dielectric withstand voltage.
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 coating is applied in a non-uniform, discontinuous manner to create regions of varying coating thickness and composition along the fastener surface. This local variation allows certain areas to provide lubricity while other areas maintain electrical conductivity, resolving the contradiction between reducing installation force and preserving electrical conductivity.
Solution Approach 2:
The invention uses a composite coating system comprising multiple layers or materials with different properties. The coating includes regions with high lubricity characteristics and regions with high electrical conductivity characteristics, creating a composite structure that simultaneously addresses both the lubricity and conductivity requirements.
2Reliability
If a protective metal sleeve is used, then electrical energy dissipation is improved, but cost and complexity increase
Solution Approach 1:
The invention merges the fastener shaft and coating into a single integrated component rather than using separate metal sleeves. The coating is directly applied to the fastener shaft surface, combining the structural function of the shaft with the protective and conductive functions of the coating, thereby reducing complexity while maintaining electrical energy dissipation capability.
Solution Approach 2:
The coating provides a cost-effective alternative to expensive metal sleeves. By applying a relatively thin coating layer rather than using substantial metal sleeve components, the invention achieves similar electrical energy dissipation performance at lower material and manufacturing 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
The solution reduces installation force while ensuring effective electrical energy dispersion across the fastener surface, balancing structural and electrical design constraints at a lower cost compared to metal sleeves.
Implementation Method 1
the coating exhibits a higher lubricity than the surface of the shank so that the irregular, coating covered portions of the surface of the shank exhibit a higher lubricity than the irregular portions of the surface of the shank exposed and free of coating
Implementation Method 2
the coating exhibits a higher dielectric withstand voltage than the surface of the shank so that charge dissipates via the irregular portions of the surface of the shank exposed and free of coating before the dielectric withstand voltage of the coating, of the irregular, covered portions of the surface of the shank is met
Data Source
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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 (510) 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 (522). The coating exhibits a higher lubricity than the surface, and the coating exhibits a higher dielectric withstand voltage than the surface.