Inline method for producing a spring strip profile for a slatted frame
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Solution Overview
Problem
The existing inline methods for producing spring strip profiles with fiber-reinforced plastic core strands and thermoplastic cover layers face challenges such as low throughput speeds and economic inefficiencies due to the need for interim storage and high frictional forces during the pultrusion process, which limits the production speed and increases costs.
Innovation Solution
The method involves partial curing of the reaction resin in the fiber bundle's outer layer before extrusion, using lateral wrapping with threads or filaments and a heating section to stabilize the core strand, allowing for post-curing during storage and transport, and utilizing a thermoplastic cover layer as a heat insulator to accelerate curing from the inside out.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the pultrusion process is used to produce the core strand, then the core strand can be formed with sufficient mechanical strength, but the throughput speed is very slow and cannot meet the requirements of downstream extrusion
Solution Approach 1:
The patent applies preliminary action by pre-curing the reaction resin in the fiber bundle before extrusion. A heating section is introduced to partially cure the reaction resin in advance, so that when the fiber bundle enters the extruder, the resin has already reached a sufficient curing degree to withstand the extrusion process without deforming the core strand cross-section. This preliminary curing action resolves the contradiction by enabling faster throughput while maintaining manufacturing precision.
2Productivity
If the heated pultrusion tool is extended to provide higher heat input, then the curing speed increases, but the frictional forces become unmanageable
Solution Approach 1:
The patent segments the curing process into two distinct stages: (1) a heating section that provides controlled heat input to initiate and accelerate curing before extrusion, and (2) a cooling section that follows the heating section to reduce temperatures and frictional forces before the material enters the extruder. This segmentation allows high curing speed to be achieved without generating unmanageable frictional forces, as the cooling section removes excess heat and reduces friction.
3Manufacturing precision
If complete curing of the core strand is achieved before extrusion, then the cross-section remains stable, but the production time is significantly increased
Solution Approach 1:
The patent applies partial action by curing the reaction resin only to a sufficient degree before extrusion, rather than achieving complete curing. The heating section is designed to reach a specific temperature and residence time that provides enough curing for cross-section stability during extrusion, but not necessarily 100% completion. This partial curing approach maintains manufacturing precision while significantly reducing production time, as the remaining curing can occur during or after extrusion without affecting product quality.
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 significantly increases throughput speeds, achieving rates of 4 m/min or more, while maintaining the mechanical strength and stability of the core strand, allowing for complete curing during storage and reducing production time and costs.
Implementation Method 1
thermally activating the reaction resin to form a cured core strand
Implementation Method 2
thermally activating the reaction resin to form a cured core strand
Implementation Method 3
applying thermoplastic melt in the extruder head to form the cover layer on the spring strip profile
Implementation Method 4
cooling and calibrating the spring strip profile in a cooling and calibrating device
Data Source
AI summary
An inline method for producing a spring strip profile (1) for a slatted frame that comprises at least one core strand (2) formed by a fiber-reinforced plastic and at least one thermoplastic cover layer (3) surrounding the core strand (2), comprises at least the following steps: joining multiple fibers, threads and/or filaments to form a fiber bundle (2.1); impregnating the fiber bundle (2.1) with a thermally activatable reaction resin; molding the outer contour of the fiber bundle (2.1) impregnated with the reaction resin; thermally activating the reaction resin (2.1) to form a cured core strand; introducing the core strand (2) into an extruder head (110); applying thermoplastic melt in the extruder head (110) to form the cover layer (3) on the spring strip profile (1); and cooling and calibrating the spring strip profile (1) in a cooling and calibrating device (111, 112, 113). The outer contour of the fiber bundle (2.1) is wrapped around, in a winding machine (105), by at least one thread or filament (2.2) supplied laterally in relation to the fiber bundle in at least one position and orientation, and, in a heating section (106), before the core strand (2) is introduced into the extruder head (110), at least a partial curing of the reaction resin is achieved, at least in the wrapped outer layer of the fiber bundle (2.1).