Star-Shaped Preform Bottom for Weight Reduction
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Solution Overview
Problem
There is a challenge in reducing the weight of plastic containers made by blow-molding or stretch blow-molding without compromising their mechanical strength, as existing methods struggle to identify effective ways to lighten the preforms without impacting their structural integrity.
Innovation Solution
A preform design featuring a bottom part with ribs extending from the apex to the periphery, forming a star shape, and including substantially triangular zones of reduced thickness between ribs, which allows for weight reduction while maintaining mechanical strength and uniform material distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the wall thickness of the bottom part is reduced to save weight, then the weight of the preform and container decreases, but the mechanical strength of the bottom part deteriorates
Solution Approach 1:
The patent applies local quality by creating zones of reduced thickness specifically in the triangular areas between ribs, while maintaining greater thickness in the rib structures themselves. This allows weight reduction in non-critical areas while preserving mechanical strength in load-bearing regions. The rib structures act as reinforcement elements that locally concentrate material where strength is needed, permitting thinner walls elsewhere.
Solution Approach 2:
The bottom part is segmented into rib structures and triangular zones with different thickness characteristics. The ribs extend from the apex to the periphery, dividing the bottom into distinct segments. This segmentation allows different parts of the bottom to have optimized thickness profiles - thicker ribs for structural support and thinner triangular zones for weight reduction.
2Weight of moving object
If material is removed from the bottom part to reduce weight, then the weight of the preform decreases, but the uniform distribution of plastics material toward the neck deteriorates
Solution Approach 1:
The patent applies local quality by creating zones of reduced thickness specifically in the triangular areas between ribs, while maintaining greater thickness in the rib structures themselves. This allows weight reduction in non-critical areas while preserving mechanical strength in load-bearing regions. The rib structures act as reinforcement elements that locally concentrate material where strength is needed, permitting thinner walls elsewhere.
Solution Approach 2:
The bottom part is segmented into rib structures and triangular zones with different thickness characteristics. The ribs extend from the apex to the periphery, dividing the bottom into distinct segments. This segmentation allows different parts of the bottom to have optimized thickness profiles - thicker ribs for structural support and thinner triangular zones for weight reduction.
Data Source
AI summary
The invention relates to a preform (1) for a container (2) made of plastic, wherein the preform (1) comprises a body part (3) comprising a wall having a thickness (e1) which extends along a longitudinal axis (X) and which is connected, via a periphery (8), to a closed bottom part (5) which has an apex (10). According to the invention, the bottom part (5) has ribs (11) which each extend from the apex (10) of the bottom part (5) to the periphery (8) so as to form a star, and a substantially triangular zone (12) arranged between two adjacent ribs (11) and a portion (8a) of the periphery (8) has a thickness (e3) which is less than the thickness (e1).