Flexible Base Design for Hot-Fill Plastic Containers
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Solution Overview
Problem
Plastic containers designed for hot-fill processes face challenges due to content cooling and associated shrinkage, which creates internal vacuum forces that can lead to structural issues such as creasing and uneven displacement of the container base.
Innovation Solution
A base design for plastic containers featuring an outer support ring, a structured formation ring with sequential formations, and an inner inversion portion that can flex to accommodate vacuum forces, distributing stress evenly and allowing for uniform displacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the container base is made rigid to maintain structural stability, then the container can support its shape, but the base cannot accommodate vacuum forces during cooling, leading to creasing and uneven displacement
Solution Approach 1:
The base design incorporates an inversion portion that can dynamically change its configuration in response to vacuum forces. This portion is designed to invert or fold inward when vacuum pressure is applied during cooling, allowing the base to adapt its shape rather than resist the forces rigidly, thereby preventing creasing while maintaining overall structural stability.
Solution Approach 2:
The base includes a flexible inversion portion that acts as a controlled flexible element within the otherwise rigid base structure. This portion is designed with appropriate thickness and material properties to allow controlled deformation under vacuum forces while the rest of the base maintains its structural integrity and stability.
2Strength
If the base structure is reinforced to prevent deformation, then structural integrity is maintained, but stress distribution becomes uneven, causing creasing and localized damage
Solution Approach 1:
The base is segmented into different functional portions: a rigid outer support ring that maintains overall structural integrity, and a flexible inversion portion that specifically handles vacuum forces. This segmentation allows each portion to perform its specialized function, with the inversion portion distributing stress evenly through its controlled deformation rather than concentrating stress that would lead to creasing.
Solution Approach 2:
Different portions of the base have different structural properties tailored to their specific functions. The outer support ring has high rigidity for structural support, while the inversion portion has controlled flexibility for stress distribution. This local differentiation of quality allows the base to maintain overall strength while managing stress distribution through the flexible portion.
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 base design effectively manages vacuum-induced stress, preventing creasing and ensuring uniform displacement, thus maintaining container integrity during cooling and handling.
Implementation Method 1
at least the inner inversion portion is configured to flex in response to internal vacuum forces associated with container
Data Source
AI summary
A base for a plastic container including an outer support portion; a structured formation ring including a plurality of sequential formations; an inner inversion portion disposed radially inwardly of the structured formation ring; and a central portion. In an embodiment, the sequential formations are disposed in a substantially ring-like configuration and at least the inner inversion portion is configured to flex in response to internal vacuum forces associated with said container.