Composite Thermoplastic Sheet Integral Hinge Design
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Solution Overview
Problem
Existing methods for incorporating hinges into thermoplastic sheets, such as those used in automotive instrument panels with airbag doors, are costly and complex, relying on steel inserts, plastic clips, or glued-on support skins, which increase manufacturing costs and complexity.
Innovation Solution
A composite thermoplastic sheet with a permeable core layer of reinforcing fibers bonded with a thermoplastic material and a flexible elastomeric skin laminated to provide an integrated hinge area, allowing for bending and reducing fabrication costs through thermoforming processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If steel inserts, plastic clips, or glued-on plastic support skins are used to provide hinge function, then the hinge function is achieved, but article costs, fabrication equipment costs, and manufacturing complexity increase
Solution Approach 1:
The patent merges the hinge function directly into the thermoplastic sheet by incorporating a hinge line during the molding process itself. This integration eliminates the need for separate hinge components (steel inserts, plastic clips, or glued-on skins) and their associated assembly steps, thereby reducing manufacturing complexity while maintaining reliable hinge functionality.
Solution Approach 2:
The molded-in hinge line serves multiple functions: it provides the hinge mechanism for movable portions, maintains structural integrity of the sheet, and enables cost-effective manufacturing. This multi-functional design replaces multiple separate components with a single integrated feature that accomplishes all necessary functions.
2Reliability
If steel inserts, plastic clips, or glued-on plastic support skins are used to provide hinge function, then the hinge function is achieved, but article costs and fabrication equipment costs increase
Solution Approach 1:
By combining the hinge function into the molding process itself, the patent eliminates the need for separate hinge components and their associated purchase, inventory, and assembly costs. The hinge line is created as an integral feature during sheet fabrication, significantly reducing overall manufacturing costs while maintaining functional reliability.
3Shape
If fiber reinforced thermoplastic sheets are subjected to sharp bends during stamping or molding, then articles with deep draw sections and bent shapes can be formed, but the sheet requires enhanced flexibility in specific areas
Solution Approach 1:
The patent applies local quality by creating a hinge line with specific localized properties (reduced fiber concentration or modified material composition) in the area where flexibility is needed. This allows the sheet to be formed into complex shapes with deep draw sections while maintaining enhanced flexibility only in the specific hinge area, rather than requiring the entire sheet to be flexible.
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 integrated hinge function enables cost-effective and simplified manufacturing of articles with deep draw sections and bent shapes, such as automotive instrument panels, while maintaining structural integrity and reducing material costs.
Implementation Method 1
heating the core layer to a temperature sufficient to melt the first thermoplastic material
Implementation Method 2
laminating the flexible thermoplastic skin to the core layer to form a laminate structure
Data Source
AI summary
A composite thermoplastic sheet includes, in an exemplary embodiment, a permeable core layer having a first surface and an opposing second surface. The core layer includes a plurality of reinforcing fibers bonded together with a first thermoplastic material. The composite sheet also includes a flexible thermoplastic skin laminated to and covering at least a portion of the first surface of the core layer. The core layer includes about 20 weight percent to about 80 weight percent reinforcing fibers.