Intermediate Frame for Blow Molding Preform Insertion
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Solution Overview
Problem
In the production of large plastic containers, especially fuel tanks, incorporating large inserts and maintaining diffusion-tightness is challenging due to the instability of flat semi-finished products during handling and the limited freedom of movement for introducing inserts, which can lead to leakage and complex sealing issues.
Innovation Solution
A method involving an intermediate frame in the tubular preform that allows for partial preforming, separation into stable parts, and introduction of inserts before final blow molding, ensuring the preform's round cross-sectional stability and accessibility, with the option to use a C-shaped or closed cross-section and flexible binders for improved handling and integration of complex inserts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the tubular preform is cut open to form flat semi-finished products for insertion into blow molding tool, then accessibility to interior is improved, but stability during handling deteriorates due to strong heating and tendency to stick together
Solution Approach 1:
The preform is divided into two flat semi-finished products that can be handled separately. The intermediate frame holds these segments apart during insertion, preventing them from sticking together while maintaining accessibility to the interior for insert placement.
Solution Approach 2:
An intermediate frame is introduced as a mediator between the two flat semi-finished products and the blow molding tool. This frame maintains the separation of the unstable preform segments during handling and insertion, preventing direct contact and sticking while enabling interior accessibility.
2Stability of the object's composition
If the preform is slit into C-shaped cross section, then dimensional stability is improved, but freedom of movement for introducing large inserts deteriorates
Solution Approach 1:
The preform is divided into flat semi-finished products that can be separated and manipulated independently. This segmentation provides dimensional stability while allowing the blow molding tool to be opened wide for introducing large inserts without restriction.
Solution Approach 2:
The preform transitions from a closed tubular structure to flat semi-finished products, changing the dimensional configuration. This allows the blow molding tool to access the interior fully while maintaining the structural integrity of the preform segments during handling.
3Ease of operation
If multiple openings are made in tank wall for inserting built-in parts, then accessibility for inserts is improved, but sealing complexity and leakage risk increase
Solution Approach 1:
The preform is separated into flat semi-finished products before insertion into the blow molding tool. This preliminary action creates accessibility to the interior for inserting built-in parts while maintaining the integrity of the preform structure, eliminating the need for multiple openings in the tank wall and reducing sealing complexity.
4Ease of operation
If flat semi-finished products are used for insertion, then accessibility is improved, but difficulty in handling increases due to strong heating and sticking tendency
Solution Approach 1:
An intermediate frame serves as a mediator that holds the flat semi-finished products apart during handling and insertion. This frame prevents the heated plastic segments from sticking together while maintaining accessibility to the interior for insert placement.
Solution Approach 2:
The intermediate frame extracts and isolates the flat semi-finished products from direct contact with each other during handling. By taking out the preform segments and holding them separately in the frame, the sticking tendency is prevented while maintaining the necessary accessibility.
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 enables problem-free introduction of large inserts and improved handling of extrudates, maintaining the preform's stability during transport and ensuring all inserts are firmly integrated into the finished article, minimizing leakage points and post-processing time by optimizing the introduction and separation of parts within the blow molding tool.
Implementation Method 1
shaping of the preform within a blow molding tool with at least two halves using differential pressure to form a hollow body
Implementation Method 2
The binders include hinges and joints located at the top corners of the frame. The lower corners of the frame are pivotally connected to retraction arms. The frame is folded with the help of a tube through which air is introduced into the blow mould.
Implementation Method 3
The lower corners of the frame are pivotally connected to retraction arms
Implementation Method 4
The frame is folded with the help of a tube through which air is introduced into the blow mould
Data Source
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AI summary
The invention relates to a method for producing a plastic article (9), comprising extruding an approximately tubular blank (1) from an extrudate and shaping the blank (1) into a hollow body inside a blow-mould (2, 5, 3) using differential pressure, wherein at least one insertable part (6) is introduced into the interior of the partially moulded plastic article (9) before the latter is fully shaped into a finished plastic article (9), and the tubular blank (1) is arranged between at least two halves (2, 3) of a blow-mould by means of an intermediate frame (4).