Microcapillary Wire Coating Die Assembly for Single-Layer Cable Jackets

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Solution Overview

Problem

The production of cable jackets with microcapillary structures is challenging due to the need for larger diameter dies, increasing capital and operating costs, especially when aiming for a single polymeric layer with embedded microcapillaries.

Innovation Solution

A microcapillary wire coating die assembly featuring a mandrel assembly with a housing and cone-shaped tip, allowing for the application of a polymeric coating with microcapillaries to a wire or optic fiber, utilizing a die assembly that includes a housing wire tubular channel, fluid annular channel, and nozzles to form microcapillaries in a single layer, reducing die diameter and costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a larger diameter die is used to produce cable jackets with microcapillary structures, then the microcapillaries can be formed, but the capital and operating costs increase

Engineering Contradiction:
Improvemicrocapillary structure formationVSAvoidcapital and operating costs
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent embeds a mandrel assembly with microcapillary-forming nozzles inside the die assembly. The mandrel is positioned within the die cavity, and microcapillaries are formed by injecting material through nozzles on the mandrel surface during the extrusion process. This nested configuration allows microcapillary formation without requiring a larger die diameter, thus reducing capital and operating costs while maintaining manufacturing precision.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The die assembly is divided into separate functional components: the die body for jacket formation and the mandrel assembly for microcapillary formation. The mandrel assembly includes multiple nozzles arranged to create microcapillaries at specific locations. This segmentation allows independent optimization of each component, enabling precise microcapillary formation without increasing overall die size.

Inventive Principle:
Principle #1Segmentation

2Device complexity

If a single polymeric layer with embedded microcapillaries is produced, then the structure is simplified, but the die design becomes more challenging

Engineering Contradiction:
Improvecable jacket structureVSAvoiddie design complexity
Core Design Contradiction:
Device complexityVSEase of manufacture

Solution Approach 1:

The mandrel assembly is pre-configured with nozzles positioned to inject material at specific locations and angles during the extrusion process. The nozzles are arranged on the mandrel surface to create the desired microcapillary pattern in the single polymeric layer. This preliminary configuration of the mandrel allows for complex microcapillary structures to be formed within a simplified single-layer design without requiring complex die geometry.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The mandrel assembly acts as an intermediary device between the extrusion system and the final cable jacket product. It mediates the formation of microcapillaries within the single polymeric layer by injecting material through controlled nozzles during extrusion. This intermediary mechanism simplifies the overall die design while enabling complex single-layer structures with embedded microcapillaries.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

Enables the efficient extrusion of cable jackets with microcapillaries in a single polymeric layer, reducing capital and operating costs while maintaining ease of installation and tear strength, with a 75% reduction in strip force required for tearing compared to traditional solid jackets.

Implementation Method 1

a fluid annular channel encircling the wire tubular channel; a fluid ring in fluid communication with the fluid annular channel

Methodology Applied
Scientific EffectFluid pressure: Pressure Increase

Implementation Method 2

one or more nozzles in fluid communication with the tip fluid channel, the nozzles located at the end and extending beyond the narrow end of the tip

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Data Source

PatentEP3548252B1Microcapillary wire coating die assembly
Publication Date: 2022.05.18 DOW GLOBAL TECHNOLOGIES LLC
  • EP3548252B1 patent drawingFigure 1A~1B
  • EP3548252B1 patent drawingFigure 1C
  • EP3548252B1 patent drawingFigure 2A~2B

AI summary

Polymeric coatings comprising microcapillary structures are applied to a wire or optic fiber using a wire coating apparatus comprising a die (13) assembly comprising a mandrel assembly (16) comprising: (A) a housing (12) comprising: (1) a housing (12) wire tubular channel extending along (a) the length of the housing (12), and (b) the longitudinal centerline axis of the housing (12); (2) a fluid annular channel encircling the wire tubular channel; (3) a fluid ring (28) in fluid communication with the fluid annular channel, the fluid ring (28) positioned at one end of the housing (12); and (B) a cone-shaped tip having a wide end and a narrow end, the wide end of the tip attached to the end of the housing (12) at which the fluid ring (28) is positioned, the tip comprising: (1) a tip wire tubular channel extending along (a) the length of the tip, and (b) the longitudinal centerline axis of the tip; (2) a tip fluid channel (27) in fluid communication with the fluid ring (28); and (3) one or more nozzles (29A) in fluid communication with the tip fluid channel (27), the nozzles (29A) located at the end and extending beyond the narrow end of the tip; the housing (12) wire tubular channel and the tip wire tubular channel in open communication with one another such that a wire can pass from one to the other in a straight line and without interruption.