Fiber Laser Marking Can Ends with Photonically Active Pigments
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Solution Overview
Problem
Conventional methods for decorating metal cans, particularly two and three piece beverage cans, face limitations in speed and resolution due to the use of CO2 lasers that often result in burning, etching, or ablating the lacquer, which restricts the amount and quality of decoration that can be achieved on high-speed production lines.
Innovation Solution
A high-speed, high-resolution laser marking process that uses a CO2 laser with a beam width of less than 50 microns to apply images to metal can ends and pull tabs without burning, etching, or ablating the lacquer, utilizing a photonically active component that changes appearance, such as thermally active pigments, to create detailed images on the can ends and pull tabs, including machine-readable codes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional CO2 laser is used for decorating can ends at high speed, then production speed can be maintained, but the laser resolution deteriorates to approximately 100 microns and causes burning, etching, or ablating of the lacquer
Solution Approach 1:
The patent changes the wavelength parameter of the laser from conventional CO2 laser (10.6 micrometers) to fiber laser (1 micrometer), enabling high-speed operation while maintaining fine resolution of 5 microns or less. This parameter change allows the laser to interact differently with the photonically active component, achieving decoration at production speeds without burning or etching the lacquer.
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 has superior characteristics for this application. The fiber laser's different wavelength and beam characteristics enable it to heat the photonically active component rapidly and locally, producing the desired color change without the harmful side effects of conventional lasers.
2Manufacturing precision
If laser power is increased to maintain decoration quality at high speed, then image clarity is improved, but the lacquer is burned, etched, or ablated
Solution Approach 1:
The patent changes the wavelength parameter from CO2 laser (10.6 micrometers) to fiber laser (1 micrometer), which fundamentally alters how the laser energy interacts with the photonically active component. This enables concentrated energy delivery that produces rapid localized heating and color change without the thermal diffusion that causes burning and etching of the surrounding lacquer.
Solution Approach 2:
The photonically active component serves as an intermediary that absorbs the fiber laser energy and converts it to a color change. This intermediary mechanism allows the laser to produce the desired visual effect without directly heating or damaging the lacquer binding material, as the energy is absorbed and converted at the molecular level of the photonic component.
3Ease of manufacture
If conventional laser marking is used to remove dark lacquer and expose aluminum, then simple logos can be created, but the process speed is limited and decoration complexity is restricted
Solution Approach 1:
The patent replaces the mechanical removal process (laser ablation of lacquer to expose aluminum) with a chemical/optical transformation process (laser-induced color change of photonic component). This substitution eliminates the need for high-power lasers and complex multi-step processes, enabling high-speed single-pass decoration that can create complex images including machine-readable codes.
Solution Approach 2:
The patent changes the fundamental mechanism from material removal to color transformation. By using a fiber laser with wavelength optimized for the photonic component's absorption characteristics, the process achieves rapid decoration at production speeds while maintaining the ability to create simple or complex designs as needed.
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
Enables high-speed decoration of can ends and pull tabs with precise, high-resolution images that can withstand pasteurization and retort temperatures, allowing for efficient production while maintaining image integrity and machine readability, even after the can is opened.
Implementation Method 1
applying a laser to the coated substrate to change an appearance of at least a portion of the photonically active component substantially without burning, etching, or ablating the lacquer
Implementation Method 2
coating at least a portion of the can end substrate, preferably with a lacquer, that includes a photonically active component
Data Source
AI summary
A system and method for laser marking can end, including a can end center panel and/or pull tab. The decorated can end and/or tabs may have a machine readable image.