Plastic Container Base Tension Band Curvature
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Solution Overview
Problem
Existing plastic container designs, particularly PET containers with petaloid bottle bases, face challenges in distributing material evenly during the stretch blow molding process, leading to issues like dents, stress whitening, and visible distortions due to wide tension bands and early cooling of PET material, which compromises base stability and material utilization.
Innovation Solution
A plastic container design featuring a base region with at least three supporting feet and a groove base acting as a tension band, where the groove base has distinct curvature properties in central and lateral regions, allowing for better material distribution and stability by fitting the tension band into the base geometry, avoiding distortions, and enhancing the stretching process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a wide tension band is used in the base region, then base stability is improved, but material distribution during stretching deteriorates, causing dents and stress whitening
Solution Approach 1:
The tension band is divided into multiple zones with different curvature radii: a first zone with a larger curvature radius for stability, and a second zone with a smaller curvature radius for improved material distribution. This local differentiation allows each zone to optimize its function while resolving the contradiction between base stability and material distribution quality.
2Force
If a wide tension band is used, then force transfer capability is improved, but stretching process deteriorates, causing visible distortions
Solution Approach 1:
The tension band incorporates zones with different curvature radii optimized for specific functions. The first zone with larger curvature radius handles force transfer effectively, while the second zone with smaller curvature radius facilitates proper material stretching, thereby resolving the contradiction between force transfer capability and stretching process quality.
3Stability of the object's composition
If material is collected in the tension band region, then base center positioning is improved, but material consumption increases
Solution Approach 1:
Instead of uniformly collecting material throughout the tension band, the invention concentrates material in specific zones with larger curvature radii while using zones with smaller curvature radii for efficient material distribution. This localized material collection approach maintains base center positioning stability while reducing overall material consumption.
4Ease of manufacture
If PET material arrives at the mold too early and cools down, then material handling is simplified, but tension band region strength deteriorates due to chatter marks
Solution Approach 1:
The varied curvature radius design creates zones that control material flow and temperature distribution during molding. Certain zones with specific curvature characteristics prevent excessive cooling and chatter mark formation in critical areas, thereby maintaining tension band strength while allowing simplified material handling procedures.
Data Source
AI summary
A one piece plastic container having a base region, a base body adjoining such base region in the longitudinal direction of the plastic container, and a mouth region adjoining such base body in the longitudinal direction and having a mouth, wherein the base region has at least three supporting feet, at least one groove with a groove base extending in the circumferential direction over a circumferential angle arranged between adjacent supporting feet, the groove base acts as a tension band. The groove base has a central tension band region in which the wall of the container is inwardly bulged and arranged in the circumferential direction between two lateral tension band regions. The groove base is in a cross-section perpendicular to the longitudinal direction in the central tension band region according to a first curvature property and designed in the two lateral tension band regions according to a second curvature property.