Coextrusion Head Channel for Tire Insert Profile Integrity
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Solution Overview
Problem
Existing methods for extruding complex profiled elements for tire treads face challenges in maintaining the profile integrity of inserts due to turbulence and pressure variations during the coextrusion process, particularly when using rubber compounds with different rheologies.
Innovation Solution
A coextrusion method using a coextrusion machine with an upstream and downstream extruder, where the first rubber compound forms a sublayer and an insert, and the second compound forms the tread, with the insert being circulated through a channel to maintain continuity with the sublayer and avoid contact with the tread compound until the downstream gap, ensuring the profile is protected and integrated without deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the insert is extruded through a coextrusion head with multiple ducts, then the insert can be positioned within the tread compound, but the profile of the insert may be disturbed due to turbulence and pressure variations during coextrusion
Solution Approach 1:
The coextrusion head is divided into separate functional sections: an upstream extrusion canal for the sublayer/insert compound, a downstream extrusion canal for the tread compound, and a channel system that segments the flow paths. This segmentation allows independent control of each compound's extrusion parameters, preventing turbulence-induced profile distortion while maintaining precise insert positioning.
Solution Approach 2:
A channel system acts as an intermediary structure between the upstream extrusion canal and the extrusion orifice. This channel guides the first rubber compound (forming the insert) separately from the second rubber compound (tread), mediating their interaction to prevent direct turbulent mixing while ensuring proper integration at the orifice. The channel effectively decouples the extrusion processes of the two compounds.
2Manufacturing precision
If the insert compound flows directly to the extrusion orifice, then the extrusion process is simple, but the insert profile becomes distorted due to contact with the tread compound and pressure variations
Solution Approach 1:
The extrusion process is segmented into distinct flow paths: the upstream extrusion canal delivers the insert compound through a dedicated channel system, while the downstream extrusion canal delivers the tread compound through a separate path. This segmentation maintains manufacturing simplicity by using standard extrusion components while achieving precise profile control through spatial separation of the compound flows.
Solution Approach 2:
The channel system introduces a longitudinal dimension to the extrusion process, extending the path of the insert compound from the upstream extrusion canal to the extrusion orifice. This dimensional extension allows the insert compound to be delivered and positioned accurately without direct interference from the tread compound, maintaining profile integrity while managing process complexity through spatial arrangement.
3Manufacturing precision
If turbulence occurs during coextrusion of compounds with different rheologies, then mixing may occur, but the insert profile becomes disturbed and structural integrity is compromised
Solution Approach 1:
The channel system serves as an intermediary flow path that separates the extrusion streams of the two rubber compounds. By providing dedicated channels for each compound, the system eliminates turbulent mixing that would occur with direct coextrusion, maintaining insert profile integrity while preserving production efficiency through continuous extrusion of both compounds.
Solution Approach 2:
The channel system creates localized flow control zones within the coextrusion head. The upstream channel specifically manages the insert compound flow with controlled velocity and pressure, while the downstream channel manages the tread compound. This local quality control prevents turbulence at critical interfaces, maintaining profile integrity without sacrificing overall process efficiency.
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 effectively protects the insert profile and ensures a seamless integration with the tread compound, reducing turbulence-related disruptions and maintaining the structural integrity of the complex profiled element.
Implementation Method 1
a portion of the first rubber compound, intended to form the insert, is circulated between walls of a channel which extend in a longitudinal direction between the upstream profiling blade and the downstream profiling blade
Implementation Method 2
an upstream extruder and a downstream extruder delivering into an extrusion cavity formed by the space comprised between a lower wall of an extrusion head and a profiling wall positioned opposite the lower wall
Data Source
AI summary
The method for the coextrusion of a complex profiled element made up of the assembly of profiled elements formed from distinct rubber compounds. A coextrusion machine comprises upstream and downstream extruders which deliver into an extrusion cavity. A first profiled element, formed of the first rubber compound, is created. The first profiled element comprises at least a first profiled-element portion which is intended to form a longitudinal insert, a base of which is in continuity of material with the first profiled element. A complex profiled element formed of the first and second rubber compounds is created. The insert is circulated between walls of a channel extend in a longitudinal direction between the upstream profiling blade and the downstream profiling blade and together form a concave surface open towards the inside of the extrusion cavity in such a way that the bringing-together of the lateral walls of the insert with the second compound takes place only in the downstream gap.