Rigid Hollow Casing With Long-Fibre Thermoplastic Layers
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Solution Overview
Problem
Existing methods for manufacturing rigid hollow protection casings with thermoplastic materials fail to effectively incorporate long reinforcing fibers, leading to irregular surfaces and increased production costs due to the need for additional polishing, and lack the necessary resistance and resilience provided by these fibers.
Innovation Solution
A two-layered thermoplastic structure is used, with a first layer composed of a matrix of long-fibre fabric and a second layer of a different thermoplastic material, ensuring precise distribution of long fibers and a smooth surface finish, while maintaining high resistance and resilience.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If an injection moulding process of thermoplastic material is used to manufacture the shell, then the material can be easily injected and completely fill all the nooks and crannies of the mould, but long reinforcing fibres cannot be introduced ensuring correct distribution
Solution Approach 1:
The shell is divided into multiple layers with different functions: an outer layer with short fibres for surface finish, an intermediate layer with long fibres for reinforcement, and an inner layer for impact absorption. This segmentation allows each layer to be optimized for its specific purpose without compromising the others.
Solution Approach 2:
The invention uses composite materials combining thermoplastic matrix with both short and long fibres. The short fibres provide surface smoothness while long fibres provide structural reinforcement. This composite approach resolves the contradiction by allowing both injection moulding ease and correct fibre distribution through multi-layer construction.
2Ease of manufacture
If short fibres are used to form an outer layer in the shell, then the shell can be manufactured by injection moulding, but the surface finish becomes irregular and uneven requiring sanding and polishing
Solution Approach 1:
Different regions of the shell have different fibre compositions: the outer layer contains short fibres for surface quality, while inner layers contain long fibres for strength. This local differentiation allows the outer surface to achieve smooth finish suitable for injection moulding while internal layers provide reinforcement.
Solution Approach 2:
The multi-layer composite structure combines short-fibre outer layers for surface finish with long-fibre inner layers for reinforcement. This allows the shell to simultaneously achieve ease of manufacture via injection moulding and high surface finish quality without requiring additional sanding and polishing steps.
3Strength
If long fibres are included in the thermoplastic matrix to provide resistance and distribute stress, then the casing gains improved mechanical properties, but the injection moulding process cannot ensure correct distribution of fibres
Solution Approach 1:
The shell structure is segmented into multiple layers where long fibres are concentrated in intermediate and inner layers rather than being distributed throughout the entire shell. This segmentation allows long fibres to provide strength and stress distribution in critical areas while the outer layer maintains injection moulding feasibility.
Solution Approach 2:
The invention employs composite materials with long fibres embedded in thermoplastic matrix within specific layers. This composite construction provides the necessary resistance and resilience through long fibre reinforcement while maintaining manufacturability by limiting long fibre content to layers where they provide maximum benefit without compromising injection moulding.
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 solution provides improved resistance and resilience with a smoother surface finish, reducing the need for polishing and lowering production costs by ensuring uniform fiber distribution and enhanced abrasion resistance.
Implementation Method 1
a thermoplastic material is employed that solidifies by the application of heat, so that after the moulding the shell hardens
Implementation Method 2
other layers of softer or deformable material, such as foam or padded elements, intended to absorb as much energy as possible from the impact and to deform to increase the deceleration distance
Data Source
AI summary
The rigid hollow protection casing (30) includes a first rigid layer (10) composed of a matrix of a first thermoplastic material (11) including in its interior at least one long-fibre fabric layer (12) selected from fibreglass, carbon fibre and/or aramid fibre and comprising between 45% and 65% of the total weight of the first layer (10); a second overlapping rigid layer (20) exterior to the first layer (10), the second layer (20) being entirely composed of a matrix thereof or of a second thermoplastic material (21), the second layer (20) comprising between 2% and 10% of the total weight of the casing (30).