Single Mold Plastic Container Forming System
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Solution Overview
Problem
Existing systems for forming containers from plastic materials require multiple molds and heating/cooling cycles, leading to inefficiencies and defects, especially when dealing with high molecular weight plastics and semifinished products with thin thickness or paste states.
Innovation Solution
A compact forming system using a single mold arrangement with a punch and abutting device for compression-forming and expansion, allowing for a single heating cycle and improved control over the forming process, enabling the creation of preforms that can be subsequently expanded into containers without prior expansion phases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple molds and heating/cooling cycles are used for forming containers, then the forming process can accommodate different plastic materials, but the operational complexity and production time increase
Solution Approach 1:
The patent combines multiple forming operations (compression-forming and blow-forming) into a single mold arrangement. The mold includes both a compression-forming cavity and a blow-forming cavity that can be used sequentially without removing the workpiece, thereby reducing the number of molds and operational steps while maintaining versatility for different plastic materials
Solution Approach 2:
The mold arrangement is designed to perform multiple functions: it can compression-form semifinished products into preforms, then subsequently blow-form those preforms into final containers. This multi-functional capability eliminates the need for separate dedicated molds for each forming stage, reducing overall device complexity
2Reliability
If multiple heating and cooling cycles are used to form semifinished products and containers, then complete forming cycles are achieved, but production time and energy consumption increase
Solution Approach 1:
The process maintains continuous heating through the transition from compression-forming to blow-forming. The heating phase is not interrupted between operations, and the mold remains in a heated state throughout both forming stages, eliminating the need for intermediate cooling cycles and reducing total production time while ensuring complete forming cycles
3Adaptability or versatility
If semifinished products with thin thickness or paste state are used, then material versatility is improved, but forming control and defect prevention become more difficult
Solution Approach 1:
The compression-forming operation is performed first to create a preform with improved structural integrity and uniform wall thickness distribution. This preliminary shaping action prepares the semifinished product (whether thin-gauge disc or paste dose) for the subsequent blow-forming operation, ensuring better control and reducing defects before the final expanding stage
4Device complexity
If a single mold arrangement is used for both compression-forming and expansion, then device complexity is reduced, but the ability to optimize each forming stage independently is limited
Solution Approach 1:
The single mold arrangement is segmented into distinct functional zones: a compression-forming cavity and a blow-forming cavity. Each cavity is designed with specific features optimized for its respective operation, allowing independent optimization of each forming stage while maintaining physical integration in a single mold unit
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 the production of defect-free containers with controlled thickness, facilitating stretch-blow-forming and reducing operational complexity, while utilizing high molecular weight plastics effectively and optimizing heating phases for improved container formation.
Implementation Method 1
expanding said preform in said forming mould by means of a punch inserted into said mould through said opening
Implementation Method 2
subjecting the plastic material to a complete heating and cooling cycle to form the semifinished product
Implementation Method 3
subjecting the plastic material to a complete heating and cooling cycle to form the semifinished product
Data Source
AI summary
A method comprises forming a preform of plastic material, expanding said preform to obtain a container, said forming comprising compression-forming said preform in that mould arrangement wherein said expanding occurs; a method comprises expanding a preform in a mould arrangement to obtain a container, before said expanding it being provided to form a dose of plastic material in a paste state in said mould arrangement to obtain said preform; an apparatus comprises a forming mould arrangement, a punch device for expanding a preform in said mould arrangement, an abutting device cooperating with said punch device, said punch device and said abutting device identifying a configuration in which said punch device and said abutting device cooperate to define a forming unit for compression-forming a semifinished product of plastic material to obtain said preform and a further configuration in which said punch device and said abutting device cooperate to define an expansion unit of said preform to obtain a container.