Thermoplastic Container Surround Embedding via Vacuum Pulling
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Solution Overview
Problem
The existing methods for producing thermoplastic containers with metal surrounds, such as fuel tanks, require high blowing pressure and prolonged cycle times due to the viscosity of the plastic material and the need for pre-blowing, which is inefficient and time-consuming.
Innovation Solution
A method using a multi-part blow mold with a surround structure that allows preforms to be pulled into cavities via vacuum, eliminating the need for high blowing pressure and pre-blowing, and utilizing a tool like a bell or mold ram to press the preform into the surround, reducing cycle time and ensuring a secure seal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high blowing pressure is applied to ensure the plastic material penetrates the surround structure, then the surround is securely enclosed by the container wall, but the production cycle time is prolonged due to the need to maintain pressure for a certain time
Solution Approach 1:
The surround structure is pre-assembled with the closure system before the blowing process, and the mold is pre-heated to optimal temperature. This preliminary preparation ensures that when the plastic material is introduced, it immediately flows through the surround structure without requiring prolonged pressure maintenance, thus reducing cycle time while maintaining sealing quality
Solution Approach 2:
The invention optimizes the temperature and pressure parameters of the plastic material during the blowing process. By controlling the material temperature within a specific range and applying optimized pressure profiles, the material achieves optimal flow characteristics that allow quick penetration through the surround structure, reducing the time pressure must be maintained while ensuring secure enclosure
2Reliability
If pre-blowing is performed at appropriate pressure and holding time to connect the surround to the container wall, then the surround is intimately connected to the container wall, but the production process becomes relatively time-consuming
Solution Approach 1:
The surround structure is pre-positioned and secured in the mold cavity before the preform is introduced. This preliminary action eliminates the need for time-consuming pre-blowing operations to locate and secure the surround, as it is already in its final position. The connection integrity is maintained because the preform is designed to naturally flow to and connect with the pre-positioned surround during the main blowing process
Solution Approach 2:
The invention eliminates the separate pre-blowing step by integrating the surround connection function into the main blowing process. By designing the mold and preform system appropriately, the plastic material flows directly through the surround structure during the primary blowing operation, achieving intimate connection without requiring a separate, time-consuming pre-blowing and holding phase
3Loss of time
If a multi-part blow mold with vacuum pulling is used to eliminate pre-blowing, then the production cycle time is reduced, but the method requires a tool to press the preform into the surround structure
Solution Approach 1:
The mold is divided into multiple parts with distinct functions: one part provides the cavity for vacuum pulling, while another part contains the pressing mechanism for the surround structure. This segmentation allows each component to perform its specific function efficiently - vacuum pulling for rapid preform formation and a dedicated pressing mechanism for secure surround connection - thereby managing complexity through functional separation rather than requiring a single complex integrated system
4Manufacturing precision
If the surround is placed in the mold as an insert and completely embedded in the thermoplastic, then the container opening is properly provided, but high blowing pressure and prolonged pressure maintenance are required due to material viscosity
Solution Approach 1:
The invention optimizes the temperature parameters of both the mold and the plastic material to reduce material viscosity during the blowing process. By maintaining the material at optimal temperature, it flows more easily through the surround structure without requiring high blowing pressure. The embed depth is controlled by the geometry of the surround structure and the vacuum pressure applied during pulling, rather than relying on high blowing pressure, thus achieving precise embedding with reduced stress
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 significantly reduces production cycle time, enhances the quality of sealing surfaces, and eliminates the need for excess pressure and venting, resulting in a more efficient and faster production process for thermoplastic containers.
Implementation Method 1
pulling the preforms into the cavities, preferably by evacuating the cavities
Data Source
AI summary
The invention relates to a method for producing a container (2) from a thermoplastic, having at least one surround (4), provided in the container wall (1), for a container opening. The surround (4) comprises a structure behind which parts of the container wall (1) extend and/or which is penetrated by said parts. The method is carried out using a multi-part blow mold that has at least two mold parts, each having at least one cavity, wherein the surround is placed as an insert in the cavity (10) of the blow mold (7). The method comprises pressing the preform that has been forced into the cavity (10) into the structure of the surround (4) by means of a tool which is brought to bear on the preform (12) on the side of the preform facing away from the cavity (10).