Vehicle Load Floor Sandwich Panel Surface Quality
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Solution Overview
Problem
Current sandwich load floor panels in vehicles suffer from poor surface appearance and texture due to the foaming process, which also leads to bubble defects and visibility of glass fibers, necessitating additional aesthetic layers that increase weight and complexity.
Innovation Solution
A sandwich panel design featuring a core layer covered by fibrous layers, with a polyether polyurethane resilient slab foam layer that is fully penetrated by polyurethane foam, forming a dense skin layer on the surface without fully filling the core structure, thereby enhancing surface definition and scratch resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If polyurethane foam is used to bind layers in a sandwich panel, then the layers are bound together and lightweight construction is achieved, but the foam creates bubble defects and poor surface appearance
Solution Approach 1:
The patent divides the foam application into two distinct segments: a first foam layer applied to bind the core and facing layers together, and a second foam layer applied specifically to fill surface features and create the final surface appearance. This segmentation allows each foam layer to serve its specific function without compromising the other, resolving the contradiction between binding strength and surface quality.
Solution Approach 2:
The patent applies the first foam layer preliminarily to bind the structural layers together before applying the second foam layer for surface finishing. This preliminary binding action ensures structural integrity is established first, allowing the subsequent surface foam to focus solely on aesthetic requirements without being compromised by structural needs.
2Strength
If pressure is applied during molding to bind layers, then the layers are bound together, but the polyurethane is forced inside the honeycomb rather than filling surface features
Solution Approach 1:
The patent segments the foam application process into two distinct stages with different pressure and application conditions. The first foam layer is applied under conditions optimized for penetrating to the core for binding, while the second foam layer is applied to fill surface features without being forced into the honeycomb structure, thus achieving both binding and surface definition.
Solution Approach 2:
The patent applies different foam characteristics and application methods to different locations: the first foam layer targets the interface between core and facing for binding, while the second foam layer targets the surface features for aesthetic definition. This local differentiation resolves the contradiction by optimizing each location for its specific function.
3Manufacturing precision
If additional layers are added to improve B-surface appearance, then surface quality improves, but weight and production complexity increase
Solution Approach 1:
The patent merges the binding function and surface finishing function into a single integrated sandwich panel structure using two foam layers applied during the same molding process. This integration eliminates the need for separate post-production aesthetic layers, reducing both weight and production complexity while achieving the desired surface quality.
Solution Approach 2:
The patent makes the foam material multi-functional by using it for both structural binding (first layer) and aesthetic surface finishing (second layer). This universality eliminates the need for additional specialized aesthetic layers, thereby reducing overall part complexity and weight while maintaining high surface 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
The proposed solution achieves improved surface definition, increased scratch resistance, and a more versatile lightweight alternative to traditional load floors, without the drawbacks of bubble defects and visible fibers, thus optimizing the production process and final product quality.
Implementation Method 1
wet polyurethane foam that is compressed to impregnate fibers in the fibrous layer with the wet polyurethane foam
Implementation Method 2
During this molding step the polyurethane reacts by forming foam thereby increasing the pressure inside the closed mold
Implementation Method 3
The impregnated foam binds the layers together
Data Source
AI summary
Sandwich panel for use in a vehicle comprising at least a core layer and two fibrous layers in contact with and firmly connected to the core layer, both sides being impregnated with polyurethane whereby the polyurethane is embedding the fibers and binding to the board material, and whereby the sandwich panel further comprises at least a polyether polyurethane foam layer fully impregnated with polyurethane and in contact and firmly connected to the outer surface of at least one fibrous layer by the polyurethane, and a skin layer on the outer surface of the polyether polyurethane foam not in contact with the fibrous layer consisting of compressed polyurethane.