Container Base Inversion Design for Hot-Fill Vacuum Absorption
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Solution Overview
Problem
Current plastic containers, particularly PET containers, face challenges in maintaining material integrity and weight reduction while effectively absorbing vacuum and pressure forces, especially during hot-fill processes, due to suboptimal base designs.
Innovation Solution
The development of a container with a lightweight base configuration featuring a central pushup portion and strategically designed straps, which allows for improved vacuum response and structural integrity by optimizing the dimensions and shape of the base to minimize material usage and enhance performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the base design is optimized to reduce material usage, then container weight is reduced, but the ability to absorb vacuum and pressure forces deteriorates
Solution Approach 1:
The base is divided into multiple functional zones including a standing ring, heel, center pushup portion, and inversion portion. This segmentation allows each zone to perform specific functions - the standing ring provides structural support, the heel absorbs concentrated loads, and the inversion portion manages vacuum forces, achieving weight reduction while maintaining strength through optimized functional distribution
Solution Approach 2:
Different regions of the base are designed with different wall thicknesses and structural characteristics. The heel area has increased thickness for load bearing, while other areas use thinner walls to reduce weight. This local differentiation of material properties optimizes the balance between weight reduction and vacuum/pressure resistance
2Ease of manufacture
If the base wall thickness is reduced to minimize material usage, then manufacturing cost decreases, but the structural integrity and durability deteriorate
Solution Approach 1:
The base structure is segmented into zones with different material requirements. High-stress areas like the heel use thicker walls for durability, while low-stress areas use thinner walls to minimize material usage and manufacturing cost, achieving cost-effectiveness without compromising overall structural integrity
Solution Approach 2:
The base employs local quality variations with different wall thicknesses in different regions. The heel and standing ring areas have increased thickness for structural integrity, while the inversion portion and other areas use reduced thickness to minimize material usage, balancing durability and manufacturing cost
3Ease of manufacture
If the base design is simplified to reduce complexity, then manufacturing process becomes easier, but the vacuum response performance deteriorates
Solution Approach 1:
The base is designed with segmented functional zones that can be formed using standard blow-molding techniques. The standing ring, heel, center pushup portion, and inversion portion are created as integrated features during the molding process, maintaining manufacturing simplicity while achieving superior vacuum response through optimized geometric segmentation
4Strength
If more material is used in the base, then vacuum absorption capacity improves, but container weight increases
Solution Approach 1:
The base uses local quality optimization where material thickness is increased only in areas requiring high vacuum absorption capacity, such as the heel and center pushup portion, while other areas use thinner walls. This targeted material distribution improves vacuum absorption capacity without proportionally increasing overall container weight
Solution Approach 2:
The base structure is segmented to concentrate material in functional zones that provide vacuum absorption capacity. The heel, standing ring, and inversion portion are designed with optimized material distribution to maximize vacuum response while minimizing overall material usage and container weight
Data Source
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AI summary
A container including an opening defined by a finish portion, and a base at an end of the container opposite to the opening. The base includes a standing ring extending inward from a heal to a center pushup portion. The center pushup portion includes an pushup ring surrounding an inversion portion. In an as-blown position the inversion portion extends outward and beyond the pushup ring such that the inversion portion is further from the opening than the pushup ring. In a final position the inversion portion is inverted relative to the as-blown position such that the inversion portion extends inward so as to be closer to the opening than the pushup ring. The inversion portion is mechanically moved from the as-blown position to the filled position with an inversion device after the container has been filled to reduce vacuum or increase pressure within the container.