Fuel Tank Connection Element Integration via Extrusion Blow Molding
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Solution Overview
Problem
Existing methods for producing fuel tanks from thermoplastic materials by extrusion blow molding face challenges in creating leak-proof connections for ventilation lines and electrical components, as the plastics used tend to swell with fuel and are not diffusion-tight, leading to potential leakage points and complex manual assembly processes.
Innovation Solution
A method involving a multi-part tool with a slide is used to integrate connection elements during the manufacturing process, where the connection element pierces the container wall while still in a plasticized state, eliminating the need for additional welding steps and minimizing damage, using a tool with a circumferential cutting edge or needle tip to form a profiled contour that remains as a part of the container wall.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If connection elements are welded to the container wall after production, then connection reliability is improved, but assembly complexity and manual labor increase
Solution Approach 1:
The connection elements are pre-integrated into the container wall during the extrusion blow molding process itself, rather than being attached afterward. The multi-part tool with slide mechanism positions and secures connection elements while the plastic material is still in its plasticized state, performing the connection action preliminarily during production.
Solution Approach 2:
The connection element integration is merged with the container production process. The multi-part tool combines the functions of forming the container wall and integrating connection elements into a single manufacturing step, eliminating separate assembly operations.
2Reliability
If connection elements penetrate the container wall after production, then connection reliability is improved, but the container wall suffers damage and requires additional sealing
Solution Approach 1:
The penetration and connection actions are performed preliminarily during the extrusion blow molding process while the material is still plasticized and formable. The connection elements are positioned and secured before the container wall fully solidifies, avoiding damage to the finished product.
Solution Approach 2:
The material state parameter is changed during the process. The container wall material is maintained in a plasticized state during connection element integration, allowing the material to be formed and sealed around the connection elements without suffering damage that would occur if the material were already solid.
3Adaptability or versatility
If manual assembly steps are used to connect fittings and valves, then connection flexibility is improved, but productivity decreases
Solution Approach 1:
The manual assembly operations are merged into the automated extrusion blow molding process. The multi-part tool with slide mechanism automates the positioning and connection of fittings and valves, combining what were previously separate manual steps into the continuous production process.
Solution Approach 2:
Connection elements are preliminarily positioned and secured during the molding process itself, eliminating the need for subsequent manual assembly steps. The slide mechanism performs the connection action while the container is being formed, ahead of the normal production sequence.
4Reliability
If complex two-component connection elements are used, then leakage prevention is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The connection elements perform their own sealing function through the integration process itself. As the connection elements are pressed through the plasticized container wall by the multi-part tool, the material flows around and seals the connection elements automatically, without requiring separate sealing components or complex two-component designs.
Solution Approach 2:
The material state parameter enables simplified connection elements. While the material is in a plasticized state, it can be easily formed and sealed around simple connection elements. After cooling and solidification, the material provides the sealing function, eliminating the need for complex sealed or two-component designs.
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 allows for simplified and leak-resistant integration of connection elements during production, reducing assembly effort and minimizing leakage risks, while maintaining the integrity of the container wall.
Implementation Method 1
A method is proposed for producing a container (10), in particular a fuel tank, from a thermoplastic material by extrusion blow molding, with at least one connection element (3) which is at least partially materially connected to the container wall (19) for connection to lines (4) leading out of or into the container (10). The connection element (3) is pressed through the wall (19) of the container (10) with the connection element (3) still in its original plasticized state.
Data Source
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AI summary
The invention relates to a method for manufacturing a container (10), in particular a fuel tank, from thermoplastic material by extrusion blow molding, wherein the container (10) is provided with at least one first connecting element (20) penetrating its wall (19) during its forming process within a multi-part tool (12a, 12b, 13), wherein at least a portion of the connecting element (20) acts as a lost die, displacing and removing the wall of the container (10) from one side into a tool (12a) located on the opposite side of the container wall. The invention further relates to a fuel tank with at least one connecting element (20) that is at least partially bonded to the container wall (19).