Metal Closure Ring Profiling for Accurate Lug and Curl Forming
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Solution Overview
Problem
Conventional methods for forming curls and lugs on metal closures with no end panel, such as those described in WO 2009/115377, face challenges in supporting the cylindrical wall during forming and ensuring accurate lug formation without unwanted deformation.
Innovation Solution
A method involving a cylindrical pushing tool with a ledge and protrusions to form lugs and curls, where the ring is slid over the tool to seat on the ledge and pushed into a forming tool with separate internal and external parts to control lug formation and curl shape, allowing for precise angle formation and inward bending of the ring ends.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional methods are used to form curls and lugs on metal closures with no end panel, then the closure can be manufactured, but the cylindrical wall cannot be properly supported during forming leading to unwanted deformation
Solution Approach 1:
A cylindrical support tool with a ledge acts as an intermediary device between the forming tools and the ring. The ledge provides a stable seating surface for one end of the ring during forming operations, while the cylindrical body supports the cylindrical wall to prevent unwanted deformation. This mediator enables precise lug formation by stabilizing the unsupported ring structure throughout the forming process.
2Stability of the object's composition
If a cylindrical pushing tool is used to support the ring during forming, then the cylindrical wall is supported, but the ring becomes difficult to remove from the tool
Solution Approach 1:
The cylindrical pushing tool is divided into two distinct segments: a ledge portion that provides the seating surface for one end of the ring, and a cylindrical body portion that supports the cylindrical wall. This segmentation allows the ring to be firmly held during forming while enabling easy removal afterward, as the separate functional zones reduce interference between support and ejection operations.
3Manufacturing precision
If the ring is firmly held during forming to prevent deformation, then manufacturing precision is improved, but the forming process becomes more complex
Solution Approach 1:
The cylindrical support tool with ledge serves multiple functions simultaneously: it supports the cylindrical wall to prevent deformation, provides a stable seating surface for the ring end, and facilitates easy ring removal after forming. By consolidating these functions into a single multi-functional device, the solution improves manufacturing precision without significantly increasing overall process complexity.
Data Source
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AI summary
A modular method of forming a two part metal closure comprises a lug forming module for forming lugs (3) on a ring (1), a panel curl module, and an assembly module which fixes the panel inside the ring whilst allowing axial movement of the panel for opening.