Impact-Extruded Aluminum Bottle Neck Alloy for Strong ROPP Threads
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Solution Overview
Problem
Existing impact extrusion processes for manufacturing aluminum beverage containers struggle to produce containers with integral threaded necks strong enough to securely close with a roll on pilfer proof (ROPP) closure, due to the softness and low mechanical properties of traditional aluminum alloys.
Innovation Solution
The use of a higher strength aluminum alloy, comprising at least partly recycled scrap material, during the impact extrusion process to form containers with integral threaded necks capable of securely closing with a ROPP closure. This alloy is specifically formulated to provide the necessary mechanical strength while allowing for thinner walls, reducing manufacturing costs and environmental footprint.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional aluminum alloys (1070 or 1050) are used in impact extrusion, then the container can be formed, but the mechanical strength is insufficient to support integral threading for ROPP closures
Solution Approach 1:
The patent changes the chemical composition parameters of the aluminum alloy by incorporating recycled aluminum (3003, 3104, or 3105 alloys) mixed with pure aluminum (1070 or 1050). This composition change increases the mechanical strength and hardness of the material, enabling the formation of integral threads that can support ROPP closures while maintaining manufacturability through impact extrusion.
Solution Approach 2:
The patent creates a composite aluminum alloy system by combining different aluminum alloys (recycled 3003/3104/3105 with pure 1070/1050). This composite material approach achieves the desired balance between strength for threading and ductility for forming, resolving the contradiction between mechanical strength and ease of manufacture.
2Strength
If higher strength aluminum alloy is used, then integral threads strong enough for ROPP closures can be formed, but the wall thickness must be increased to maintain structural integrity
Solution Approach 1:
The patent optimizes the alloy composition parameters to achieve high strength-to-weight ratio. By carefully controlling the mix of recycled aluminum (30-70%) and pure aluminum (30-70%), the material gains sufficient strength for threading without requiring increased wall thickness, thus maintaining thin-walled container design.
3Ease of manufacture
If recycled aluminum scrap material is used, then manufacturing cost is reduced and environmental footprint is decreased, but the mechanical properties and consistency of the alloy are compromised
Solution Approach 1:
The patent establishes specific compositional parameters for the recycled aluminum alloy (30-70% recycled content mixed with 30-70% pure aluminum). This parameter optimization ensures that the mechanical properties remain sufficient for impact extrusion and threading while maximizing the use of cost-effective recycled materials.
Solution Approach 2:
The patent applies different quality requirements to different portions of the final product. The neck region requires higher strength for threading, while the body can use lower proportions of pure aluminum. This local quality approach allows cost-effective use of recycled materials while ensuring critical areas meet performance requirements.
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 approach enables the manufacture of lower-cost, thin-walled aluminum containers with high-performance integral threads, capable of securely closing pressurized beverage containers, thus addressing the limitations of traditional impact extruded containers.
Implementation Method 1
The force from the punch deforms the metal slug around an outer diameter of the punch and the inner diameter of the confining die
Data Source
AI summary
The present invention relates generally to forming a threaded neck in a metal bottle manufactured by a process known as impact extrusion. More specifically, the present invention relates to methods, apparatus and alloy compositions used in the impact extrusion manufacturing of containers and other articles with sufficient strength characteristics to allow threading the container necks to receive a threaded closure on the threaded neck.