Petaloid Bottle Base Geometry for Low-Pressure Blow Molding
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Solution Overview
Problem
Existing blow molding processes for plastic bottles require high blowing pressures, typically above 20 bars, which are costly and strain machinery robustness, while existing bottle bases do not meet mechanical standards for carbonated beverages under internal pressure, drop resistance, and chemical resistance without compromising structural integrity.
Innovation Solution
A bottle base design with a hemispherical shape and petaloid foot formation, featuring a specific ratio of maximum foot depth to sitting radius and angles between valley flanks, allows for a blowing pressure of less than 16 bars while maintaining mechanical integrity, including resistance to internal pressure, drops, and chemical stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional bottle base designs are used, then mechanical strength and durability are achieved, but blowing pressure must be above 20 bars which increases energy consumption and machinery strain
Solution Approach 1:
The base is designed with a substantially hemispherical underlying geometrical form and rounded foot profiles, eliminating sharp corners and stress concentration points. This spherical curvature distributes internal pressure evenly across the base structure, allowing the bottle to withstand 10 bar internal pressure while reducing the blowing pressure required during manufacturing to below 16 bars.
Solution Approach 2:
The invention optimizes specific geometric parameters of the base: the ratio of maximum foot depth to sitting radius is set to 0.5±0.01, and the angle between valley flanks is controlled at 37±3 degrees. These parameter optimizations create a base structure that achieves maximum mechanical strength with minimal material, thereby reducing the blowing pressure needed during manufacturing while maintaining durability.
2Use of energy by moving object
If blowing pressure is reduced below 16 bars, then energy consumption and machinery strain are minimized, but mechanical resistance towards internal pressure and drop resistance may be compromised
Solution Approach 1:
The base is divided into multiple feet (typically 5) arranged in a petaloid pattern around the central axis, with valleys separating adjacent feet. This segmentation creates a structure that distributes mechanical stresses from drops and internal pressure across multiple load-bearing elements, enhancing overall reliability while allowing reduced blowing pressure during manufacturing.
Solution Approach 2:
The base structure combines the hemispherical underlying form with the petaloid foot formation to create a composite geometric structure. This composite design integrates the stability of a hemisphere with the load-distributing benefits of multiple feet, achieving superior mechanical resistance to drops and internal pressure while being manufacturable at blowing pressures below 16 bars.
3Use of energy by moving object
If petaloid foot formation with specific geometry is used, then blowing pressure is reduced to below 16 bars, but manufacturing precision requirements increase to maintain the specific ratio of foot depth to sitting radius
Solution Approach 1:
The invention establishes specific parameter ranges for the base geometry: maximum foot depth to sitting radius ratio of 0.5±0.01 and valley flank angle of 37±3 degrees. These well-defined parameters provide clear manufacturing targets that balance precision requirements with the benefit of reduced blowing pressure, making the design both manufacturable and energy-efficient.
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 new bottle base design achieves mechanical stability and durability required for carbonated beverages with a reduced blowing pressure, meeting industry standards while minimizing energy consumption and machinery strain.
Implementation Method 1
inserting, into a mold with the imprint of the container, a preform previously heated to a temperature above the glass transition temperature of the material
Implementation Method 2
injecting into the preform a fluid (particularly a gas such as air but it can also be an incompressible fluid such as water) under pressure
Data Source
AI summary
A bottle for holding a carbonated beverage comprising a body and a base having a substantially hemispherical underlying geometrical form (S1) extending from the lower end of the body. The base comprising a petaloid foot formation having axial symmetry around the longitudinal axis (X) of the bottle and formed from a plurality of feet projecting downwards from the underlying geometrical form (S1) with valleys separating adjacent pairs of feet. Each valley having a bottom line (81) following substantially the underlying geometrical form (S1). The ratio between a maximum foot depth (F) being the maximum normal distance from the underlying geometrical form (S1) to a surface of a foot (S2) and a sitting radius being the radius of the largest circle formed by the points of contact with the feet and a flat surface (9) when the bottle is stood vertically on the flat surface, is 0.5±0.01.