Laser-Profiled Interference Fit Fasteners for Controlled Bond Strength
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Solution Overview
Problem
Current interference fit fastening methods, such as press-fit and shrink-fit, face challenges including high insertion forces, excessive plastic deformation, and costly assembly/disassembly processes, with limitations in controlling bond strength and joint life times, especially in applications requiring precise tolerances and ease of maintenance.
Innovation Solution
A novel laser micro-profiling technique is used to alter the surface texture of metal pins, allowing precise control over the interference-fit bond strength by varying laser parameters, enabling the creation of defined Moire patterns for secure and reliable fastening with controlled insertion and removal forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional press-fit or shrink-fit methods are used to achieve interference fit fastening, then secure bonding and joint strength are improved, but excessive plastic deformation and high insertion forces occur
Solution Approach 1:
The laser micro-profiling process is applied to the pin surface before the interference fit assembly, pre-configuring the surface geometry to control the bonding interface. This preliminary surface modification allows for optimized stress distribution during assembly, reducing excessive plastic deformation while maintaining secure bonding.
Solution Approach 2:
The laser micro-profiling creates localized surface features (such as grooves, ridges, or textured patterns) at specific regions of the pin surface. These localized geometric modifications concentrate the interference fit effects at targeted areas, distributing stresses more evenly and reducing overall plastic deformation while maintaining adequate bond strength.
2Manufacturing precision
If tight tolerances are enforced to control insertion forces, then manufacturing precision is improved, but device complexity and cost increase
Solution Approach 1:
The laser micro-profiling technique replaces complex mechanical tolerance control systems with a controlled surface modification process. By using laser parameters (power, speed, pattern) to define surface geometry, the method substitutes精密 mechanical machining and inspection with a more controllable thermal processing approach, simplifying the overall manufacturing system.
Solution Approach 2:
The invention controls the interference fit characteristics by changing laser processing parameters (such as power, scanning speed, pulse duration, and pattern geometry) rather than relying on tight mechanical tolerances. This parameter-based control approach provides flexibility in adjusting bond strength without requiring complex fixture systems or precision machining equipment.
3Strength
If high insertion forces are applied to achieve interference fit, then joint strength is improved, but assembly time and equipment requirements increase
Solution Approach 1:
The laser micro-profiling is performed before assembly to pre-configure the pin surface geometry. This preliminary surface preparation creates optimal contact characteristics that reduce the actual insertion force required during assembly, thereby increasing assembly speed without compromising joint strength.
Solution Approach 2:
The laser micro-profiling creates dynamic surface features that facilitate the interference fit process. The surface geometry (such as tapered grooves or progressive ridges) is designed to guide the assembly process, allowing for controlled force application that reduces peak insertion forces and enables faster, more reliable assembly.
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 method provides a rapid, low-cost, and user-friendly solution for producing interference-fit fasteners with controlled bond strengths, reduced plastic deformation, and extended joint life times, facilitating easier assembly and disassembly with minimal equipment requirements.
Implementation Method 1
A novel laser micro-profiling technique is used to alter the surface texture of metal pins
Implementation Method 2
alter the surface texture of a metal component such as a pin, to produce an interference-fit fastening element
Implementation Method 3
the friction that holds the parts together is often greatly increased by compression of one part against the other
Implementation Method 4
both parts elastically, and in many cases plastically, deform slightly in order to fit together, creating a high compressive force
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
An interference fit fastener (fig.l) and method of fabricating same is described.