Inline method for producing a spring strip profile for a slatted frame
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Solution Overview
Problem
Existing inline methods for producing spring slat profiles face low throughput speeds and economic inefficiencies due to the need for intermediate storage and slow curing processes in pultrusion, which limits production speed and increases costs.
Innovation Solution
The method involves stabilizing the core strand with spiral windings to allow immediate extrusion of a thermoplastic layer without full curing, utilizing exothermic reactions for post-curing during storage, and using a mandrel or thermoplastic core for accelerated hardening, enabling higher throughput speeds and reducing production time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the core strand is fully cured in the pultrusion process before extrusion, then the structural stability is ensured, but the production speed is significantly reduced due to the required dwell time
Solution Approach 1:
The patent applies partial curing of the core strand in the pultrusion process, achieving sufficient structural stability without complete curing. The core strand is cured to a degree that prevents deformation during extrusion, but full curing is completed later during storage or transport, thereby reducing the dwell time in the pultrusion process and increasing production speed
Solution Approach 2:
The patent performs preliminary stabilization of the core strand through partial curing and the application of a stabilizing layer during the pultrusion process. This preliminary action provides sufficient structural integrity for the subsequent extrusion process, while the final curing completes during storage, separating the stabilization function from the time-consuming full curing process
2Productivity
If the pultrusion tool is lengthened to increase heat input and curing speed, then the throughput speed increases, but the frictional forces become unmanageable
Solution Approach 1:
The patent applies partial curing in a shortened pultrusion tool, providing just enough structural stability for the core strand to withstand the extrusion process. The remaining curing occurs during storage or transport, eliminating the need for an excessively long heated tool and keeping frictional forces manageable
Solution Approach 2:
The patent introduces a stabilizing layer as an intermediary between the partially cured core strand and the extrusion process. This stabilizing layer, applied during pultrusion, provides additional structural support that allows the use of a shorter heated tool, reducing frictional forces while still enabling high throughput speeds
3Ease of manufacture
If intermediate storage of the core profile bar is implemented, then the production process can be separated into pultrusion and extrusion stages, but considerable time is lost and economic disadvantages arise
Solution Approach 1:
The patent eliminates intermediate storage by implementing continuous production where the core strand is partially cured in the pultrusion process, immediately followed by the extrusion process. The core strand maintains sufficient structural stability throughout this continuous operation, eliminating idle storage time and maintaining continuous useful action throughout the production line
Solution Approach 2:
The patent performs preliminary curing and stabilizing layer application during the pultrusion process, preparing the core strand in advance to withstand the subsequent extrusion process without requiring intermediate storage. This preliminary preparation enables direct transition from pultrusion to extrusion, eliminating storage time losses
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 production speed by allowing throughput times of over 4 m/min, achieving 25% more efficiency than conventional methods, while ensuring the core strand's stability during extrusion and post-curing, thus reducing economic losses and improving manufacturing efficiency.
Implementation Method 1
the heat of reaction is used, which arises when a suitable reaction mixture is used, which leads to an exothermic crosslinking reaction during polyester formation
Implementation Method 2
the already applied thermoplastic coating layer has a heat-insulating effect, so that the heat generated by the exothermic reaction in the reaction resin is not dissipated to the environment, but contributes to faster curing from the inside out
Data Source
Figure 1
Figure 2~4
AI summary
The invention relates to an inline method for producing a spring strip profile (1) for a slatted frame, which spring strip profile (1) comprises at least one core strand (2) formed by a fibre-reinforced plastic and at least one thermoplastic cover layer (3) surrounding the core strand (2), wherein the method comprises at least the following steps: joining multiple fibres, threads and/or filaments to form a fibre bundle (2.1); impregnating the fibre bundle (2.1) with a thermally activatable reaction resin; moulding the outer contour of the fibre 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); cooling and calibrating the spring strip profile (1) in a cooling and calibrating device (111, 112, 113), wherein, in a winding machine (105), the outer contour of the fibre bundle (2.1) is wrapped around by at least one thread or filament (2.2) supplied laterally in relation to the fibre bundle in at least one position and orientation, and wherein, 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 fibre bundle (2.1).