Seaming Lever Geometry for Thin-Walled Non-Cylindrical Cans
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Solution Overview
Problem
Existing seaming technologies struggle to produce high-quality seams on thin-walled metal cans, leading to increased reject volumes and economic challenges due to higher costs and weights associated with thicker cans.
Innovation Solution
A method for seaming thin-walled cans using a seaming unit with a first plate and a first lever, where the first lever is rotatably mounted on the first plate and connected to a second plate, allowing for precise control of the seaming trajectory and angular clearance to reduce reject volumes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional seaming unit with larger angular clearance is used, then the device complexity is reduced and ease of operation is improved, but the manufacturing precision and seam quality on thin-walled cans deteriorate
Solution Approach 1:
The invention changes the angular clearance parameter of the lever mechanism from conventional larger values to specifically less than 60 degrees (preferably less than 45 degrees). This parameter change enables precise control of the thumbwheel trajectory while maintaining the simplicity of the mechanical lever-based seaming unit structure
Solution Approach 2:
The invention makes the seaming trajectory dynamic and adaptable by allowing modification of the lever's circular trajectory diameter and angular clearance parameters. This enables the same simple mechanical structure to adapt to various can formats and shapes without increasing device complexity
2Manufacturing precision
If the first diameter is increased to reduce angular clearance, then the manufacturing precision improves, but the length of moving object increases
Solution Approach 1:
The invention optimizes the relationship between the lever's circular trajectory diameter and the angular clearance parameter. By carefully selecting these parameters together (diameter less than 60mm, angular clearance less than 60 degrees), the invention achieves high positioning precision while keeping the mechanical components compact and the thumbwheel trajectory controlled
3Weight of moving object
If thin-walled cans are used to decrease weight and cost, then the weight and cost are reduced, but the seam quality deteriorates leading to increased reject volumes
Solution Approach 1:
The invention changes the seaming process parameters by controlling the lever's angular clearance to less than 60 degrees and the circular trajectory diameter to less than 60mm. This creates a gentler, more precise seaming action that is suitable for thin-walled cans, enabling them to be seamed successfully without increasing wall thickness
Solution Approach 2:
The invention applies a more controlled and precise seaming action (partial action with smaller angular clearance) than conventional methods. This partial action approach with reduced lever movement and smaller angular clearance prevents excessive force on thin walls while still achieving adequate seam formation
Data Source
AI summary
A method for seaming a seam in a can using a seaming unit having a first plate (10) a first lever pivotably mounted on the first plate (10) at a first pivot point (53) to describe a first trajectory along a first diameter (D1); and a second plate (20) to which a second end (55) of the first lever is connected. The method includes a step of determining a value of the first diameter (D1) so as to decrease a first angular clearance of the first lever (50) about the first pivot point (53). A seaming unit using said method.