Can Bottom Leg Forming to Prevent Black Discoloration
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Solution Overview
Problem
The conventional forming process for can bottom parts often results in black discoloration due to damage of the oxide film on aluminum alloy cans, and it also complicates maintenance due to metal adhesion to rollers.
Innovation Solution
A can body forming device that includes a pressing body and a forming die, where the pressing body is inserted into the can body and abuts on the inner surface of the dome part, and the forming die shapes the lower end of the leg part to form a curved inward end, reducing friction and preventing metal accumulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a roller is used to press the inner peripheral wall of the annular leg part, then the leg part can be reformed, but the oxide film of the aluminum alloy is damaged causing black discoloration and metal material adheres to the roller requiring complicated maintenance
Solution Approach 1:
The patent extracts the harmful pressing action from the forming process by replacing the roller that contacts and damages the can surface with a forming die that shapes the leg part from the exterior, eliminating the source of black discoloration and metal adhesion while maintaining forming capability
Solution Approach 2:
The forming die acts as an intermediary tool that achieves the desired leg part shape without direct contact with the inner peripheral wall of the annular leg part, thereby preventing damage to the oxide film and avoiding metal adhesion to the forming tool
2Ease of manufacture
If the inner peripheral wall of the annular leg part is pressed using a roller, then the leg part shape can be changed, but maintenance of the forming device becomes complicated due to metal adhesion
Solution Approach 1:
The patent removes the roller component that causes metal adhesion and maintenance issues by replacing it with a forming die that achieves shape reforming through a different mechanism that does not involve pressing the inner peripheral wall, thereby eliminating the maintenance problem while preserving the shape changing capability
Solution Approach 2:
The forming die is designed as a simple, easy-to-clean component that can be quickly maintained or replaced, reducing maintenance complexity compared to the roller system that accumulates metal adhesion
Data Source
AI summary
In reforming a can bottom part, the defect of black discoloration in an associated formed portion is suppressed. A forming device for a can body, in which a cylindrical barrel part and a can bottom part are integrally formed, includes a tool used for the can body having a concave dome part in a center of the can bottom part and having an annular leg part on a periphery of the dome part to reform a shape of the leg part. The tool includes a pressing body that is inserted into the can body, and that abuts on an inner surface of the dome part, and a forming die that forms a curved end part heading inward on a lower end part of the leg part.