Lightweight Sandwich Panel Steam-Separated Wood Chipboard
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Solution Overview
Problem
Current methods for producing lightweight sandwich panels are costly and resource-intensive, with existing continuous processes facing limitations in production speed and performance properties, making them unsuitable for widespread industrial use beyond specialized applications.
Innovation Solution
A continuous method that utilizes steam pressure to separate cover layers in a conventional wood chipboard production process, allowing for the introduction of a polyurethane foam intermediate layer without external tools, which accelerates the setting process and reduces drying costs, and uses in-situ foaming to create a strong connection between layers without additional adhesives.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional continuous process is used for producing lightweight sandwich panels, then production speed can be maintained, but the production costs are too high and performance properties are inadequate
Solution Approach 1:
The cover layer serves dual purposes: as the final product component and as the heating element for foaming the intermediate layer. The residual heat from the cover layer during pressing is utilized to foam the intermediate layer, eliminating the need for separate heating systems and reducing production costs while maintaining continuous production speed
Solution Approach 2:
The pressing and foaming operations are merged into a single continuous process step. The cover layer is pressed and simultaneously used to foam the intermediate layer through its residual heat, combining two previously separate operations into one integrated process that reduces costs while maintaining productivity
2Ease of manufacture
If external tools are used to separate cover layers for introducing the intermediate layer, then the intermediate layer can be introduced, but the device complexity increases
Solution Approach 1:
The cover layer itself serves as the separating element by being lifted and folded back over the intermediate layer material. This eliminates the need for external separation tools or devices, reducing device complexity while maintaining process feasibility through the inherent flexibility and positioning of the cover layer
Solution Approach 2:
Instead of using an external tool to separate the cover layer, the cover layer is inverted by folding it back over the intermediate layer material. This reverse approach uses the cover layer's own movement to achieve separation and introduction of the intermediate layer without additional equipment
3Strength
If additional adhesives are used to connect layers, then the connection strength is improved, but the resource consumption and production cost increase
Solution Approach 1:
The polyurethane foam intermediate layer serves as both the filling material and the bonding agent. As the foam expands and cures, it naturally adheres to the cover layers, providing strong connection without requiring separate adhesive applications. This eliminates additional material consumption while maintaining connection strength
Solution Approach 2:
The intermediate layer uses polyurethane foam as a composite material that combines structural filling function with adhesive bonding function. The foam's expansion and curing process creates inherent bonding to the cover layers, replacing the need for separate adhesive materials while maintaining strong layer connection
4Manufacturing precision
If the cover layers are pressed with high pressure and temperature, then the cover layer quality is improved, but the drying time and production cost increase
Solution Approach 1:
The pressing and foaming operations are performed continuously in sequence without interruption. The cover layer is pressed to quality specifications, then immediately folded back to foam the intermediate layer using its residual heat. This continuous process eliminates separate drying steps and reduces production time while maintaining cover layer quality
Solution Approach 2:
The residual heat in the cover layer after pressing, which would normally be waste heat requiring cooling and drying time, is converted into a useful resource for foaming the intermediate layer. This transforms what would be a time-consuming cooling step into a productive foaming operation, reducing overall drying time and production cost
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 enables cost-effective, high-quality production of lightweight sandwich panels with reduced density and improved stability, suitable for broader industrial applications by optimizing production speed and eliminating the need for additional separation tools, while ensuring dimensional stability and environmental safety.
Implementation Method 1
separate the cover layers from one another by acting on the wood chipboard with steam pressure
Implementation Method 2
introduce a polyurethane foam system as an intermediate layer, which then foams in-situ
Implementation Method 3
the setting process accelerates and drying costs reduce
Data Source
AI summary
The invention relates to: A) a continuous method for producing a lightweight sandwich panel having an upper and a lower cover layer made of pressed wood chips glued to one another, as well as an intermediate hard foam layer which is thick in relation to a cover layer, arranged between the cover layers and fixedly connected thereto, the method comprising the following steps: 1) providing a scattered layer of glue-coated woodchips; 2) pressing this layer and bonding the wood chips under pressure and temperature conditions typical of conventional chipboard production such that a high vapour pressure is built up in the centre between the cover layers; 3) relieving the pressure on the chipboard by moving the pressing surfaces away from one another, whereby the chipboard tears open in the centre due to the built-up vapour pressure and divides into two cover layers of equal thickness; 4) moving the cover layers apart such that an intermediate layer can be inserted; 5) introducing a hard foam system that can be foamed and cured to form a hard foam between the cover layers; 6) bringing the cover layers together to the nominal thickness of the lightweight sandwich panel to be produced and holding the pressure until the intermediate layer has finished reacting; and 7) finishing the lightweight sandwich panel. B) The invention further relates to a lightweight sandwich panel producible according to the method described in A), with a transition zone created by the uneven portions of the cover layers on the inner side, which are filled with the polyurethane hard foam.