Deformable Flank Thermoplastic Container Design
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Solution Overview
Problem
Thermoplastic containers, such as those made of PET, face challenges in reducing material usage while maintaining mechanical performance, especially during hot filling, where thermal shocks and hydrostatic pressures cause stress, and existing structural adaptations like preferential deformation zones increase material usage and restrict design freedom.
Innovation Solution
The design incorporates hollowed-out side panels with a concave central zone and convex adjoining zone, featuring a deformable membrane at their junction to concentrate deformations, minimizing stress on other parts, and uses stiffeners and grooves to enhance rigidity and ergonomics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If the amount of material used in container manufacturing is reduced, then cost is reduced, but mechanical performance and rigidity deteriorate
Solution Approach 1:
The container wall is designed with non-uniform thickness distribution, concentrating material in critical areas (bottom, shoulder, neck) while using less material in less critical areas. This local quality variation maintains structural strength where needed while reducing overall material consumption.
Solution Approach 2:
The container employs curved surfaces and rounded transitions instead of sharp angles, particularly in the shoulder and bottom regions. These curved geometries distribute stress more effectively, maintaining mechanical performance with reduced material usage compared to angular designs.
2Strength
If conventional heat setting is used to increase crystallinity and rigidity, then container rigidity is improved, but the container remains insufficiently resistant to deformations during hot filling
Solution Approach 1:
The container is pre-formed with an ovolo groove and specific wall thickness distribution during the molding process, creating built-in structural features that preemptively prepare the container to resist deformation during hot filling, rather than relying solely on post-manufacturing heat setting.
Solution Approach 2:
The container wall is segmented into zones with different thicknesses and crystallinity levels, with the ovolo groove creating a distinct structural segment that specifically addresses deformation resistance in the shoulder region while other areas maintain appropriate rigidity.
3Reliability
If preferential deformation zones with rigid frames are added to the container, then deformation resistance is improved, but material usage increases and design freedom is restricted
Solution Approach 1:
The ovolo groove serves multiple functions simultaneously: it acts as a deformation zone, provides structural reinforcement, improves aesthetics, and facilitates gripping. By merging these functions into a single integrated feature rather than adding separate components, the design achieves deformation resistance without increasing overall complexity.
Solution Approach 2:
The preferential deformation zone with the ovolo groove is designed to serve multiple purposes: resisting deformation during hot filling, providing aesthetic appeal, improving ergonomics for gripping, and maintaining structural integrity. This multi-functionality eliminates the need for separate structural arrangements.
4Loss of substance
If the container wall is made thinner to reduce material usage, then cost is reduced, but the container becomes more sensitive to thermal shock and hydrostatic pressure
Solution Approach 1:
The container employs varying wall thicknesses in different regions, with thinner walls in less critical areas and thicker walls in areas subject to thermal shock and pressure. This localized quality variation reduces overall material usage while maintaining resistance to harmful factors where needed.
Solution Approach 2:
Curved transitions and rounded corners eliminate stress concentration points that would be particularly vulnerable to thermal shock. The smooth curved geometries distribute thermal and pressure stresses evenly throughout the wall, allowing thinner walls to withstand thermal shock effectively.
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 design allows for lighter containers with improved mechanical performance, aesthetic appeal, and enhanced ergonomics, facilitating easier gripping while reducing material usage and maintaining structural integrity under thermal and pressure changes.
Implementation Method 1
a deformable membrane is defined at the junction between the central zone and the adjoining zone. The principal function of this deformable membrane is to concentrate the essential part of the deformations during hot filling.
Implementation Method 2
which is first heated while passing through an oven provided with elements for heating by radiation
Implementation Method 3
The container is then cooled, producing a drop in pressure inside the container (essentially due to the retraction in the volume of air it contains)
Data Source
AI summary
A container made of thermoplastic material having a body in which at least one side panel is hollowed out, the container including a central zone having, in a longitudinal plane, a concave profile, and an adjoining zone longitudinally extending the central zone and having, in a longitudinal plane, a convex profile. The central zone and the adjoining zone are stiffened, and the junction between the central zone and the adjoining zone defines a deformable membrane.