Seamless Can Grounding Portion Coating Through Bottom Reformation
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Solution Overview
Problem
Existing methods for manufacturing seamless cans face challenges in reliably applying a bottom coat to the grounding portion after bottom reformation, leading to reduced conveyability and increased friction due to the absence of coating on this critical area.
Innovation Solution
A manufacturing method involving a first and second bottom-coating process, where the second coating is applied after bottom reformation using an ultraviolet curable coating material, ensuring the grounding portion is consistently coated, thereby improving conveyability and reducing friction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If bottom reformation is performed by inserting a pressing body into the preform can, then the inner periphery of the curved end can recess deeply to increase compressive strength, but the grounding portion becomes an outer peripheral wall where bottom coating is not applied, reducing conveyability
Solution Approach 1:
The patent applies preliminary action by performing the first bottom coating on the grounding portion of the preform can before the bottom reformation process. This ensures that the coating is applied to the area that will become the grounding portion after reformation, preventing coating loss during the deep recessing of the inner periphery. The preliminary coating application resolves the contradiction by preparing the surface in advance before the geometric transformation occurs.
Solution Approach 2:
The patent segments the coating process into two distinct stages: first bottom coating before reformation and second bottom coating after reformation. This segmentation allows each coating application to target specific requirements - the first coating addresses the pre-reformation grounding portion while the second coating addresses the post-reformation grounding portion, ensuring comprehensive coverage despite the geometric transformation.
2Reliability
If spray coating is used to apply bottom coating to the inner peripheral wall of the annular leg portion, then the grounding portion can be coated, but the angle and position adjustment becomes complicated, reducing productivity
Solution Approach 1:
The patent extracts the complexity of angle and position adjustment from the coating process by eliminating the need for spray coating on the inner peripheral wall. Instead, it uses a simplified coating method that applies coating to the grounding portion without requiring complex positioning, thereby maintaining reliable coating coverage while significantly improving productivity.
Solution Approach 2:
The patent employs self-service by using the pressing body and molding die in the bottom reformation process to automatically define and expose the grounding portion for coating. The reformation process itself creates the geometric configuration that facilitates subsequent coating application, eliminating the need for separate angle and position adjustments that would reduce productivity.
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 method ensures reliable application of the bottom coat to the grounding portion, enhancing compressive strength and conveyability while maintaining high productivity by simplifying the coating process.
Implementation Method 1
where the second coating is applied after bottom reformation using an ultraviolet curable coating material
Data Source
AI summary
Provided is a method for manufacturing a seamless can, which includes: molding a preform can formed with a dome portion formed at the center of a bottom portion and protruding inside the preform can and a leg portion including a grounding portion having an annular shape and formed surrounding the dome portion; performing first bottom coating of performing an outer surface coating on at least the grounding portion; performing bottom reformation of forming a curved end having an annular shape and including a grounding portion by inserting a pressing body into the preform can coated in the first bottom coating and pressing the bottom portion of the preform can by the pressing body and a molding die installed on an outer surface side of the preform can; and performing a second bottom coating of performing an outer surface coating on at least the grounding portion of the curved end.