Laser Marking via Absorbent Metal Support
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Solution Overview
Problem
Current methods for laser marking materials transparent to 1064nm, such as Plexiglas, are either expensive, complex, or result in low wear resistance markings, as they require frequency multiplication, introduction of photosensitive pigments, or use of sacrificial ceramic layers which are costly and require frequent renewal.
Innovation Solution
A method involving a highly absorbent metal support that absorbs laser radiation and transfers thermal energy to the material to be marked, allowing for local physical or chemical transformations and creating a marking without mass transfer or support degradation, using a Nd:YAG laser or similar at 1064nm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a frequency multiplier is used to obtain radiation at 355 nm for marking transparent materials, then the marking capability is improved, but the cost, device size, and energy consumption increase significantly
Solution Approach 1:
A metal support layer is introduced as an intermediary between the laser beam and the transparent material. The metal layer absorbs the 1064 nm laser radiation and converts it to thermal energy, which is then transferred to the transparent material through thermal conduction, enabling marking without requiring frequency multiplication
Solution Approach 2:
The optical system is replaced with a thermal system. Instead of using a frequency multiplier to change the wavelength of laser radiation, the patent uses thermal energy conversion and transfer: the metal support absorbs optical energy and converts it to thermal energy, which then marks the transparent material through heating
2Reliability
If photosensitive pigments are introduced into the material to enable marking at 1064 nm, then the marking capability is improved, but the manufacturing cost of the material increases
Solution Approach 1:
The metal support layer serves as an intermediary that enables marking of transparent materials without modifying the material composition. The thermal energy transfer from the metal support to the material surface allows marking of the pure transparent material, eliminating the need for photosensitive pigments
3Reliability
If a sacrificial ceramic layer is deposited on the support for marking weakly absorbent materials, then the marking effect is improved, but the device complexity and maintenance requirements increase due to frequent renewal
Solution Approach 1:
The metal support layer is self-regenerating through thermal diffusion. The thermal energy from the laser continuously diffuses metal atoms from the bulk to the surface, automatically replenishing the absorptive layer and maintaining marking efficiency without external intervention or renewal
Solution Approach 2:
The patent changes the material parameter from ceramic to metal, which enables thermal diffusion. This parameter change allows the support material to self-renew through atomic diffusion, eliminating the need for frequent replacement of sacrificial layers
4Ease of manufacture
If metal transfer marking is used for weakly absorbent materials, then the marking process is simplified, but the wear resistance of the marking is reduced
Solution Approach 1:
The patent replaces mechanical material transfer with thermal transformation. Instead of transferring metal particles onto the material surface, the thermal energy from the metal support induces physical or chemical transformations directly in the transparent material, creating durable markings that are integral to the material structure
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 efficient and cost-effective laser marking of materials like Plexiglas with improved wear resistance and no need for frequent support renewal, by utilizing thermal energy transfer from the metal support to achieve markings through local transformations.
Implementation Method 1
provide yourself with a support made of a metal that is highly absorbent at the wavelength λ, and capable of transforming at least part of the absorbed light energy into thermal energy
Implementation Method 2
arrange the article directly against the support so as to produce sufficient thermal contact between the article and the support to transfer thermal energy from the support to the article
Data Source
Figure 1
AI summary
The method involves taking a support (12) formed by a metal that is highly absorbent at wavelength for converting a part of light energy absorbed into thermal energy. An article (14) is arranged directly against the support to form sufficient thermal contact between the article and the support to transfer the energy from the support to the article. The article is placed between a laser (10) i.e. neodymium-doped yttrium aluminum garnet laser, and the support. The support is locally illuminated through the article to generate sufficient energy at the support surface.