Aerosol Dome Rolled Edge Forming for Crack-Free Radius Control
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Solution Overview
Problem
Existing methods for producing rolled edges in aerosol domes, particularly with thin and hard materials, result in uncontrolled deformation, material stresses, and aesthetically unsatisfactory edges due to the inability to maintain the desired radius and lead to wave formation and cracks.
Innovation Solution
A two-step process involving folding the initial zone of the edge section by 90° using a folding punch and counterholder, followed by rolling with a crimping die, where the folding angle and bending radius are specifically controlled to stabilize the edge and prevent wave formation, and the crimping die wraps the flange radially into the roll.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a flanging punch with a certain radius moves into a pipe section and crimps the edge into a roll, then the rolled edge is formed, but the initial zone of the rolled edge does not have the desired radius and forms a bend or kink due to uncontrolled deformation
Solution Approach 1:
The initial zone of the edge section is folded over by approximately 90 degrees to form a substantially radial circumferential flange before the crimping die is inserted. This preliminary folding action prepares the material in a controlled manner, creating a stable flange structure that prevents uncontrolled deformation and kink formation during the subsequent rolling process.
Solution Approach 2:
The rolled edge formation process is divided into two distinct steps: first folding the initial zone to create a circumferential flange, then inserting the crimping die to complete the rolling. This segmentation allows each step to be optimized independently, with the folding step controlling the initial geometry and the crimping step completing the roll formation, thereby achieving uniform radius control throughout the entire rolled edge.
2Strength
If thin and hard sheets are processed using conventional flanging, then material strength is maintained, but uncontrolled deformation and wave formation occur leading to material stresses and cracks
Solution Approach 1:
The initial zone is folded over before crimping to create a circumferential flange. This preliminary action redistributes the material in a controlled manner, preventing stress concentration that would lead to cracks. By folding first, the material is prepared to accept the subsequent crimping action without developing harmful stresses, even in thin and hard sheets.
Solution Approach 2:
The folding angle is controlled to be approximately 90 degrees, creating a specific geometric configuration that optimizes stress distribution. This parameter control ensures that the material undergoes predictable deformation with uniform stress distribution, preventing both excessive stress that causes cracks and insufficient deformation that leaves the edge unstable.
3Ease of manufacture
If the edge section is directly crimped into a roll without preliminary folding, then the process is simpler, but the resulting edge geometry is irregular and aesthetically unsatisfactory
Solution Approach 1:
The process is segmented into folding and crimping steps. While this adds one operation, the folding step creates a pre-formed circumferential flange that guides the subsequent crimping action, ensuring uniform edge geometry. The segmentation transforms a complex geometry creation task into two simpler, more controllable steps.
Solution Approach 2:
The folding of the initial zone into a circumferential flange is performed as a preliminary action before crimping. This pre-shaping step establishes the correct geometric foundation, allowing the crimping die to produce a uniform, aesthetically pleasing rolled edge without requiring complex tooling or multiple correction steps.
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 for the production of rolled edges with harder and thinner materials without material stresses, maintaining a controlled radius and preventing wave formation, resulting in a stable and aesthetically pleasing edge geometry.
Implementation Method 1
an initial zone (14) of the edge section (11) is folded by a tool (37, 34) comprising a folding punch (37) and a counterholder (34), which moves axially at least partially into the opening of the edge section (11) by an angle (a) in the range of 75-105° from the axial direction to form a substantially radial circumferential flange (41)
Implementation Method 2
subsequently a flanging die is inserted into the folded flange (41) and Retracts the edge section and flanges it into a roll (12)
Data Source
Figure 1~2d
Figure 2e~6
Figure 7~8
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.