Vertical Co-Extrusion for Uniform Filiform Polymer Coating
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Solution Overview
Problem
Existing methods for covering filiform cores with polymer material fail to achieve a uniform and homogeneous coating, often resulting in uneven thickness and the incorporation of air bubbles, which compromises the final product's physical and mechanical properties, especially for fine threads where complete coverage is not guaranteed.
Innovation Solution
An apparatus comprising an extrusion station and a stabilization station, where the filiform core is fed through a calibrating head and co-extruded with polymer material along a vertical axis, allowing for adjustable thickness and prevention of air bubbles, with feedback mechanisms to regulate the polymer material flow and tension, ensuring a uniform coating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the core is immersed in a tank containing polymer material and translated horizontally, then the core can be covered with polymer material, but the polymer material tends to go downward due to gravity causing non-uniform covering
Solution Approach 1:
The patent inverts the conventional horizontal translation approach by implementing vertical translation of the core through the polymer bath. This inversion allows gravity to work in favor of uniform material distribution around the core rather than against it, resolving the contradiction between operational simplicity and covering uniformity
Solution Approach 2:
The patent transitions from horizontal to vertical movement dimension, changing the orientation of the extrusion process. This dimensional change enables the polymer material to be extruded uniformly around the core in all directions under gravitational influence, achieving consistent covering thickness
2Manufacturing precision
If the core is immersed in a tank containing polymer material, then the core can be covered with polymer material, but air bubbles are incorporated into the covering making it uneven
Solution Approach 1:
The patent extracts air bubbles from the system by implementing a vertical extrusion process where material flows downward, allowing bubbles to rise and escape opposite to the material flow direction. This extraction principle eliminates harmful air bubbles from the final covering, ensuring homogeneity
Solution Approach 2:
The patent converts the harmful effect of air bubbles into a beneficial outcome by utilizing gravity differently - while gravity causes material to flow uniformly downward, it simultaneously allows air bubbles to rise and escape, transforming what would be trapped defects into easily removable elements
3Manufacturing precision
If a rotating roller with grooves is used to apply polymer material, then the thread can be covered, but the rotating roller generates air bubbles incorporated in the polymer material
Solution Approach 1:
The patent removes the complex rotating roller mechanism entirely, replacing it with a simpler vertical extrusion system. This extraction of the problematic component eliminates the source of air bubble generation while maintaining covering uniformity through gravitational flow control
Solution Approach 2:
The patent replaces the mechanical rotating roller system with a gravity-driven vertical extrusion system. This substitution eliminates the need for rotation and associated air bubble generation while achieving uniform material distribution through controlled gravitational flow
4Reliability
If the core is covered by immersing in polymer bath, then the core can be protected, but the covering is not complete especially for fine threads
Solution Approach 1:
The patent inverts the immersion approach by using vertical extrusion where material is applied from above downward. This inversion ensures that even fine threads receive complete material coverage as the viscous polymer flows over and around the core, guaranteeing reliable protection
Solution Approach 2:
The patent changes the physical parameters of material application by transitioning from horizontal immersion to vertical extrusion with controlled flow rate. This parameter change ensures adequate material supply and complete coverage of fine threads, achieving both reliability and precision
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 enables the production of filiform articles with a consistently uniform and adjustable polymer coating, ensuring complete core protection and desired properties without machine downtimes, suitable for various core types and thicknesses, including fine threads.
Implementation Method 1
The co-extrusion means have their extrusion axis substantially vertical so that the exiting filiform article is tensed by its own weight
Data Source
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AI summary
An apparatus to cover a filiform core (12) with a silicone-based polymer material (14), comprises an extrusion station (15) and a stabilization station (16) located downstream of the extrusion station (15). The extrusion station (15) comprises a co-extrusion body (21) suitable to receive the polymer material (14), a feeder body (20) provided with a calibrating head (22) in which the filiform core (12) to be covered transits centrally, and an exit nozzle (23) through which the filiform core (12) exits from the co-extrusion body (21) with the polymer material (14) disposed at least partly around it, along an axis of extrusion (X), forming an extruded filiform article (11).