Differential Cable Foamed Insulation Skew Control
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Solution Overview
Problem
Existing methods for manufacturing differential signal transmission cables cannot achieve a low skew of 10 ps/m or less due to dispersion of core wire positions and foaming degree in the cable cross-section.
Innovation Solution
The cable employs foamed insulation with a dispersion of foaming degree not exceeding 5% and a symmetry degree of not more than 0.10, achieved through controlled foaming extrusion molding and regulation of uneven flow index to less than 1.5, ensuring precise positioning and uniform foaming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If collective extrusion molding method is used to manufacture differential signal transmission cable, then foaming degree dispersion in longitudinal direction is reduced, but position dispersion of core wires and foaming degree in cross section increases
Solution Approach 1:
The patent applies parameter changes by controlling the extrusion molding parameters including temperature, pressure, and flow rate to achieve uniform foaming degree distribution. By optimizing these parameters, the patent reduces both longitudinal and cross-sectional dispersion of foaming degree while maintaining core wire positioning accuracy, thereby resolving the technical contradiction between composition stability and manufacturing precision.
2Ease of manufacture
If conventional cable structure with two separate foamed insulated wires is used, then manufacturing is simpler, but skew performance cannot achieve 10 ps/m or less
Solution Approach 1:
The patent merges two separate foamed insulated wires into a single collectively extruded insulating layer that covers both core wires. This merging approach maintains the simplicity of the extrusion process while achieving superior skew performance (10 ps/m or less) through uniform foaming degree distribution and precise core wire positioning within the unified insulating structure.
3Device complexity
If foaming extrusion molding is used to collectively cover core wires, then cable structure is simplified, but dispersion of foaming degree in cross section prevents achieving low skew
Solution Approach 1:
The patent applies local quality by ensuring uniform foaming degree distribution specifically in the cross-sectional regions surrounding each core wire. By controlling the extrusion process to achieve consistent foaming characteristics at different locations within the insulating layer, the patent maintains simplified cable structure while achieving the precision required for low skew performance.
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 approach results in a differential signal transmission cable with a skew of not more than 5 ps/m, suitable for high-speed transmission applications, by reducing dispersion and position deviation of core wires and foaming degree.
Implementation Method 1
a foamed insulation that collectively covers the two core wires by foaming extrusion molding
Data Source
AI summary
A differential signal transmission cable includes two core wires, and a foamed insulation that collectively covers the two core wires by foaming extrusion molding. The foamed insulation is not more than 5% in a dispersion of foaming degree defined below in a cut surface when the cable is cut orthogonally to a longitudinal direction of the cable. In the cut surface, five regions are determined according to a predetermined procedures and a foaming degree (%) of the respective regions is measured. The dispersion of the foaming degree is defined by a difference between a foaming degree (%) in the region with a maximum foaming degree and a foaming degree (%) in the region with a minimum foaming degree.