Metal Container Neck Curl Flattening for Airtight Valve Sealing
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Solution Overview
Problem
Existing manufacturing processes for metal containers, such as beverage cans and aerosol sprays, struggle to ensure a secure airtight closure due to the rounded curled portion at the open end, which lacks sufficient contact with the valve gasket, and previous methods to create a flat surface risk weakening the curled portion.
Innovation Solution
A two-step process involving pressing the curled portion to form a flat surface in a normal plane and then machining to remove the coating, maintaining the curled portion's thickness and ensuring a rougher metal surface for better gasket fixation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the curled portion is left rounded as formed, then the manufacturing process is simple, but the contact with valve gasket is insufficient leading to poor airtight closure
Solution Approach 1:
The process is segmented into two distinct sub-steps: first pressing the curled portion to create a flat surface, then machining to remove coating. This segmentation allows each step to optimize for its specific function - pressing for geometry and machining for surface quality - thereby achieving reliable airtight closure while keeping each individual step relatively simple.
Solution Approach 2:
The pressing operation is performed as a preliminary action before machining. By first creating the flat geometry through pressing, the subsequent machining step only needs to remove the coating layer rather than shaping the geometry itself, simplifying both operations and ensuring the curled portion is properly prepared for gasket contact.
2Reliability
If machining is applied to the curled portion to create a flat surface, then the contact with valve gasket is improved, but the curled portion may be weakened
Solution Approach 1:
By separating the flat surface creation into two steps - pressing for geometry and machining for coating removal - the machining operation is limited to removing only the coating layer rather than removing significant material from the curled portion itself, thereby maintaining structural strength while achieving the necessary flat surface for gasket contact.
Solution Approach 2:
The machining operation is applied partially - only to the extent necessary to remove the coating layer and create the flat surface, without excessive material removal that would weaken the curled portion. This partial action achieves the required surface quality while preserving structural integrity.
3Ease of manufacture
If a flat surface is obtained by single-step machining, then the process is simpler, but the coating removal may be insufficient and the curled portion weakened
Solution Approach 1:
The process segments surface preparation into pressing (for geometry) and machining (for coating removal), with each step optimized for its specific function. This segmentation achieves superior surface quality and complete coating removal while keeping each individual step relatively simple and well-defined.
Solution Approach 2:
The pressing operation serves as a preliminary action that pre-flats the curled portion geometry before machining. This preliminary geometric preparation ensures that the subsequent machining step only needs to remove the coating layer, achieving precise surface quality control while maintaining process simplicity.
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
The process enhances the surface area for valve gasket contact, improving airtight closure while minimizing the risk of weakening the curled portion by maintaining its thickness and ensuring a secure seal.
Implementation Method 1
a pressed tool for pressing the curled portion and obtaining a flat surface in a normal plane with respect to the main axis of the cylindrical body of the metal containers
Implementation Method 2
a machining tool for machining the curled portion and removing the coating, leaving the metal of the metal containers exposed
Data Source
Figure 1
Figure 2
Figure 3a~3e
AI summary
Process and installation for manufacturing metal containers and the metal container obtained with the process, where the process comprises supplying a metal disc, extruding the disc to form a metal container (10), applying a coating (15) on the inside of the container (10), deforming the open end (14) of the container (10) to obtain a neck (16) with a curled portion (17), and pressing the curled portion (17) to obtain a flat surface (18) in a normal plane with respect to the main axis of the container (10), and machining the curled portion (17) that has been previously pressed to remove the coating (15) from the curled portion (17), leaving the metal of the container (10) exposed.