Rolled Pipe Edge Forming for Crack-Free Aerosol Domes
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Solution Overview
Problem
Existing methods for producing rolled edges on aerosol domes using thin metal sheets result in uncontrolled deformations, material stresses, and aesthetically unsatisfactory edges, especially when using harder and thinner materials, leading to cracks and wavy edges due to uncontrolled geometry and material irregularities.
Innovation Solution
A two-step method involving folding over the starting zone of the edge portion by a folding die and counterholder at a controlled angle, followed by rolling with a flanging die, where the folding die is advanced axially and the counterholder supports the edge to achieve a stable, aesthetically pleasing rolled edge, with specific parameters for bending radius and flange dimensions to manage material stresses and anisotropy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a flanging die with a particular radius is advanced into a pipe portion to form a rolled edge, then the rolled edge shape is determined by the die geometry, but the starting zone develops uncontrolled deformations and bends due to sheet metal stability
Solution Approach 1:
A preliminary forming step is introduced before the main flanging operation. This preliminary action prepares the starting zone by creating an initial deformation pattern that prevents uncontrolled bends during subsequent rolling, thereby improving manufacturing precision without compromising the final rolled edge shape
Solution Approach 2:
The forming process is divided into multiple stages: a preliminary forming stage that addresses the starting zone, followed by the main flanging stage that forms the rolled edge. This segmentation allows each stage to optimize for its specific function, preventing the propagation of uncontrolled deformations
2Manufacturing precision
If harder and thinner sheet metal is used to meet high precision demands, then manufacturing precision improves, but material irregularities cause uncontrolled deformations and nonuniform deformations
Solution Approach 1:
The preliminary forming step uniformly distributes initial deformations across the starting zone before the main flanging operation. This pre-distribution prevents localized stress concentrations that would otherwise cause uncontrolled deformations in hard, thin materials, maintaining both precision and material stability
Solution Approach 2:
The forming parameters are optimized for hard, thin materials by controlling the preliminary forming depth and geometry. This parameter adjustment ensures that the material undergoes controlled deformation in the preliminary stage, preventing irregularities from propagating through the final rolled edge
3Manufacturing precision
If multiple intermediate processing steps are introduced to control deformations, then manufacturing precision improves, but device complexity and production costs increase
Solution Approach 1:
The preliminary forming and main flanging operations are combined into a single integrated tooling system. This merging allows both functions to be performed in sequence without requiring separate processing steps, maintaining high manufacturing precision while minimizing device complexity and production overhead
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 method allows the use of harder materials without material stresses or cracks, achieving a stable and aesthetically satisfactory rolled edge by stabilizing the collar and relieving material stresses, while avoiding intermediate processing steps that increase costs and complications.
Implementation Method 1
folding over the starting zone of the edge portion by a folding die and counterholder at a controlled angle
Implementation Method 2
a flanging die is advanced into the rolled or better folded over edge portion and flanges this into a roll
Data Source
AI summary
The invention relates to a method for producing a rolled edge from a cylindrical edge portion (11) of a pipe. In the method, a starting zone (14) of the edge portion (11) is rolled by a forcibly controlled tool (30). A flanging die (21) then advances into the rolled edge portion (11) and flanges the rolled edge portion into a roll (12). The method according to the invention is characterized in that the starting zone (14) of the edge portion (11) is folded over by the tool (30), which comprises a folding die (37) and counterholder (34), at an angle (α) in the range from 75-105° from the axial direction (45) into a substantially radially peripheral flange (41). The invention further relates to elements, in particular in the forme of an aerosol dome, having such rolled edges.