Laser-Marked Can Ends With Readable Codes Without Lacquer Damage

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Solution Overview

Problem

Conventional methods for marking metal can ends, particularly pull tabs, face limitations in speed and resolution, restricting the amount of decoration that can be achieved, and existing systems often burn, etch, or ablate the lacquer, which is undesirable.

Innovation Solution

A high-speed, high-resolution laser marking process using a CO2 laser with a beam width of less than 50 microns is applied to metal can ends and pull tabs, incorporating a photonically active component that changes appearance without burning, etching, or ablating the lacquer, enabling the creation of small, readable images and codes on both sides of the tab.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional laser etching is used on pull tabs, then decoration can be achieved, but the process speed is limited to about 700 tabs per minute and resolution is limited to approximately 100 microns

Engineering Contradiction:
Improvedecoration resolutionVSAvoidprocess speed
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent changes the laser wavelength parameter from conventional CO2 laser (10.6 microns) to fiber laser (1 micron), enabling both higher resolution (10 microns) and higher speed operation. This parameter change in laser type allows the system to overcome the traditional trade-off between resolution and speed.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the conventional CO2 laser system with a fiber laser system, substituting one type of laser technology with another that offers superior performance in both resolution and speed, thereby resolving the contradiction between manufacturing precision and productivity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Manufacturing precision

If laser power is increased to improve decoration detail, then resolution improves, but the lacquer is burned, etched, or ablated

Engineering Contradiction:
Improvedecoration detailVSAvoidlacquer damage
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent changes the laser wavelength from CO2 (10.6 microns) to fiber laser (1 micron), which interacts differently with the lacquer material. This parameter change allows achieving high decoration detail without burning or ablating the lacquer, as the fiber laser energy is absorbed more selectively by the photonically active component rather than degrading the lacquer.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent utilizes photonically active components in the lacquer that change color or appearance when exposed to the fiber laser, allowing detailed decoration to be created through color transformation rather than material removal, thereby avoiding lacquer damage while achieving high resolution.

Inventive Principle:
Principle #32Color changes

3Adaptability or versatility

If small size codes are marked on the tab to enable game play, then functionality is enhanced, but the codes become difficult to read and scan

Engineering Contradiction:
Improvegame functionalityVSAvoidcode readability
Core Design Contradiction:
Adaptability or versatilityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent uses fiber laser technology with 1 micron wavelength to achieve extremely fine resolution (10 microns), enabling small 6mm x 6mm codes to be marked with sufficient detail and contrast for easy scanning. The high resolution capability ensures that even small codes remain readable and scannable by mobile devices.

Inventive Principle:
Principle #35Parameter changes

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 high-speed decoration of can ends with detailed, machine-readable images and codes that can withstand pasteurization and retort temperatures, enhancing the functionality and aesthetic appeal of metal cans while maintaining the integrity of the lacquer.

Implementation Method 1

A high-speed, high-resolution laser marking process using a CO2 laser with a beam width of less than 50 microns is applied to metal can ends and pull tabs, incorporating a photonically active component that changes appearance without burning, etching, or ablating the lacquer

Methodology Applied
Scientific EffectLaser marking with photonically active component: Laser

Data Source

PatentEP3556675B1Method of making a can end and use of a can end for playing a game
Publication Date: 2022.12.21 CROWN PACKAGING TECH INC
  • EP3556675B1 patent drawingFigure 1A
  • EP3556675B1 patent drawingFigure 1B~1C
  • EP3556675B1 patent drawingFigure 1D~1E

AI summary

Can ends including a can end center panel and a pull tab (26) being especially decorated via machine readable images or codes (28).