Windowless Ferrule Undercut Adhesive Retention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional multi-fiber ferrules face challenges in securing optical fibers due to low-adhesion surface properties of materials like glass-filled polyphenylene sulfide, making it difficult for adhesives like epoxy to effectively bond and retain the fibers, especially in windowless designs where mechanical interlocking is limited.
Innovation Solution
The development of windowless multi-fiber ferrules with non-uniform wall thicknesses and intentionally created sink locations through injection molding, which generate undercut features that interlock with adhesive volumes to secure optical fibers, enhancing retention by varying material shrinkage during cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional smooth-walled ferrules are used, then manufacturing is simple, but adhesive bonding is insufficient due to low-adhesion surface properties
Solution Approach 1:
The ferrule transitions from a uniformly smooth surface to having localized varying wall thicknesses, creating specific regions with different adhesive bonding characteristics. The non-uniform wall thicknesses generate localized undercut features that provide mechanical interlocking while maintaining overall structural integrity.
Solution Approach 2:
The invention moves from a two-dimensional smooth surface to a three-dimensional non-uniform wall thickness structure. This dimensional change creates volumetric undercut features within the ferrule walls that provide mechanical interlocking for the adhesive, transforming the bonding mechanism from surface adhesion alone to a combination of surface adhesion and mechanical interlocking.
2Strength
If non-uniform wall thicknesses are introduced to create undercut features, then adhesive retention improves, but manufacturing precision requirements increase
Solution Approach 1:
The injection molding process itself generates the desired non-uniform wall thicknesses and undercut features through controlled cooling and shrinkage variations. The process utilizes the natural shrinkage characteristics of the plastic material during cooling to create the beneficial geometry, rather than requiring post-processing or complex multi-step manufacturing.
Solution Approach 2:
The invention changes the wall thickness parameter from uniform to non-uniform distribution within the ferrule structure. By strategically varying the wall thickness in specific regions, the design creates undercut features that provide mechanical interlocking for the adhesive, transforming a single-parameter design into a multi-parameter optimized structure.
3Strength
If windowless design is implemented, then fiber insertion visibility is reduced, but structural integrity and adhesive bonding are improved
Solution Approach 1:
The invention replaces the optical viewing method (window with visual inspection) with a mechanical solution (undercut features providing physical interlocking). The mechanical interlocking mechanism compensates for the loss of visual feedback during fiber insertion by providing inherent structural retention through the undercut geometry that physically prevents adhesive and fiber removal.
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 effectively secures optical fibers by creating mechanical interlocks between the adhesive and ferrule features, preventing axial removal and ensuring reliable fiber retention within the ferrule, even in windowless designs.
Implementation Method 1
the sink locations are caused by variations in shrinkage during cooling of the injected material that forms the ferrules
Data Source
AI summary
A windowless multi-fiber ferrule including a ferrule body. The ferrule body includes a plurality of outer slots. The ferrule body defines an inner passage that extends through a length of the ferrule body from a front end to a rear end. The inner passage includes a main chamber and a row of parallel fiber bores. The ferrule body includes a first and a second major side which each define a plurality of slots. The ferrule body includes ferrule walls which are located between the main chamber and the major sides. The ferrule walls have a first thickness at the outer slots and a second thickness at the regions between the outer slots which is thicker than the first thickness. The main chamber includes sink locations adjacent the regions between the outer slots.