Fastening Collar Coating for Visual Lockbolt Installation Check
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Solution Overview
Problem
The challenge in properly installing structural fasteners, such as lockbolts, lies in ensuring adequate deformation of the collar onto the pin during installation, which is often not achieved, leading to potential misinstallation and inefficiencies in manufacturing processes.
Innovation Solution
A multi-piece fastener system comprising a fastening collar with a coating and a pin, where the coating includes a film-forming resin and metal pigment, and a lubrication layer, allowing for visual verification of installation by partially removing the coating upon deformation, ensuring proper installation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a coating is applied to the outer collar surface for visual indication, then installation verification is improved, but friction and deformation difficulty increase
Solution Approach 1:
The coating is applied selectively to specific regions of the collar outer surface rather than uniformly across the entire surface. This localized application provides visual indication where needed while minimizing interference with the deformation process in critical areas.
Solution Approach 2:
The coating formulation is optimized to balance visual indication properties with mechanical properties. By adjusting coating thickness, composition, and curing characteristics, the coating provides sufficient visibility while maintaining acceptable friction and deformation characteristics.
2Measurement precision
If the coating is removed during deformation to indicate installation, then installation detection is improved, but coating integrity and corrosion protection deteriorate
Solution Approach 1:
The coating is applied in specific patterns or regions that allow for installation indication while preserving coating coverage in areas critical for corrosion protection. The coating removal during deformation is localized to indication zones rather than affecting the entire collar surface.
Solution Approach 2:
The coating system uses composite material formulations combining resin binders with metallic or pigment particles. This composite structure provides both the visual indication function and adequate adhesion/corrosion resistance, with the coating designed to partially remove during deformation while maintaining protective properties.
3Ease of operation
If the coating does not increase friction, then ease of deformation is improved, but coating adhesion and visual indication effectiveness deteriorate
Solution Approach 1:
The coating's friction characteristics are optimized by adjusting composition, thickness, and surface properties. The coating formulation balances low friction for easy deformation with sufficient adhesion and visual properties for effective indication.
Solution Approach 2:
Composite coating formulations combine lubricating components with pigmented or metallic particles. This allows the coating to maintain low friction coefficients for ease of deformation while simultaneously providing adequate visual indication through the embedded particles or flakes.
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 enhances the accuracy and efficiency of fastener installation by providing a visual indication of successful installation, reducing the risk of misinstallation and streamlining manufacturing processes.
Implementation Method 1
a lubrication layer intermediate the coating and the outer collar surface
Implementation Method 2
Forcibly contacting the outer collar surface at least partially removes the coating on the outer collar surface
Data Source
AI summary
Multi-piece fasteners and methods of fastening are provided. The multi-piece fastener comprises a fastening collar and a pin. The fastening collar comprises an inner collar surface defining a collar cavity, an outer collar surface, a coating on the outer collar surface, and a lubrication layer intermediate the coating and the outer collar surface. The coating comprises a resin and a metal pigment. The pin is configured to be at least partially received by the collar cavity. The pin comprises a first pin end, a second pin end, and a shank extending intermediate the first pin end and the second pin end. The fastening collar is configured to be deformed onto the shank by forcibly contacting the outer collar surface of the fastening collar. Forcibly contacting the outer collar surface at least partially removes the coating on the outer collar surface and indicates installation of the multi-piece fastener.