What is Laser Marking?
Laser marking is the process of directly marking a part surface with a focused beam of light. The result is a permanent mark that won’t disappear over time.
Laser marking technology knows no limits. You can use it to mark all types of materials and surfaces. To achieve the best results, you must first choose the ideal laser for your material. CO2 and fiber lasers are the most commonly used types of lasers. You can also modify the maximum laser power to mark at high speeds.
The laser marking processes can be optimized for specific applications to deliver better results. The two most common processes are laser etching and laser engraving. Another laser marking application is laser annealing. It’s the only viable method for marking stainless steel.
What Is Laser Marking Used For?
Laser marking is an emerging technology used in an increasing number of applications. It’s no surprise since it’s a low-maintenance technology. It’s contactless, has no moving parts, and doesn’t use consumables. In automated applications, this means that operators aren’t needed to operate laser marking machines, and they’re rarely needed to maintain them.
Laser marking is often used to implement traceability, quality control, and process improvement. By identifying each part at the beginning of a production line, barcode readers can then be used to scan identifiers at every manufacturing step. For traceability purposes, this makes it possible to track and trace parts from the beginning to the end of the manufacturing process. For quality control and process improvement, this makes it possible to store important information specific to each part in a database. The most common forms of part identification are data matrix codes, QR codes, and alphanumeric serial numbers.
The main industries that need marking solutions are the automotive, primary metals (including aluminum, steel, zinc, lead, and copper), extrusion, manufacturing, and converting industries.
How Does Laser Marking Work?
To generate a laser beam that can mark the surface of a material, light is amplified by stimulating photons. A material is first charged with energy, and its electrons release that energy in the form of light (or photons). Light is then amplified. As photons naturally stimulate the material’s atoms, its electrons release more and more photons. This creates a concentrated ray of light called the laser beam.
To mark the surface, mirrors are used to direct the laser beam in a single direction. This creates high-contrast and high-quality marks as the beam hits the material surface. By using different laser marking processes, it’s possible to mark only on the surface, or deep into the material. It’s also possible to mark under the surface, or to create a mark by removing a coating (such as paint) from the surface.
How Are Lasers Different from One Another?
To understand how lasers differ from one another, you first need to understand how wavelengths interact with materials. Here’s how it works.
In the laser source, there’s a material whose atoms release energy in the form of light. This material determines which wavelength is produced by your laser. For example, some solid-state lasers use Nd:YAG crystals to produce light. These crystals release a wavelength of 1,064 nanometers (or 1.064 microns).
Since different materials absorb wavelengths differently, you need different types of lasers for different materials. For example, you’re better off using fiber lasers to mark metals, and CO2 lasers to mark organic materials (such as plastic materials and rubber).
Different lasers can also release that energy differently. You can either use a continuous-wave laser or a pulsed laser. Whereas continuous-wave lasers continuously emit the laser beam, pulsed lasers release the beam at a set rate. Pulsed lasers can reach higher peaks of energy density because they charge up energy before releasing it. They’re ideal for laser marking applications because they offer a higher making speed. Continuous lasers are more adapted to other laser applications like laser cutting, welding, and drilling.
What Are the Benefits of Laser Marking?
Laser is becoming the new standard for most marking applications. Although it represents a higher initial investment than its alternatives, it provides a better return on investment as well as other unique benefits.
- In most cases, it’s the fastest marking solution. Looking at aluminum marking performances, it’s possible to create a high-contrast data matrix code in just 1.40 seconds.
- Laser safety is regulated by strict international standards. Based on the laser safety class of your laser machine, you can easily know whether it’s safely integrated according to your standards. For example, if you have a class-1 laser marking machine, you don’t need to implement any additional laser safety measures.
- Laser marking is a traceability solution like no other. It offers near perfect readability rates, thanks to the high reliability of laser systems and to the high contrast of marked identifiers. It can also create marks that are truly permanent, capable of withstanding almost any surface treatment such as e-coating, heat treating, and shotblasting.
- It can be used to create permanent marks on materials whose surface cannot be directly marked (like stainless steel) by creating a mark under the surface.
There are many other benefits to laser marking specific to each application. Contact us to find out which benefits apply to you.
Examples of Laser Marking Applications
Aluminum Laser Marking for Die Casters
Watch how fast a laser marker can permanently identify serial numbers and data matrix codes on aluminum die castings. 2D codes marked like this can easily be read by a barcode scanner.
Metal Laser Engraving
Watch a laser engraving system create deep marks on a large surface area. Laser engravers create diffuse patterns and deep crevices, which generates pale and dark markings. Various laser marking methods can be used to mark a wide variety of metals—from stainless steel and titanium to aluminum and magnesium.
Lead Laser Marking
Watch a soft metal like lead be marked with extensive information, including alphanumeric characters, a barcode, and a data matrix code.
Aluminum Ingot Laser Marking
Watch how laser technology handles aluminum ingots, which are known for their rough surfaces. Most direct part marking solutions have difficulty with this kind of roughness, but laser marking stands up to the challenge.
Polyethylene Laser Marking
Watch the laser marking of a plastic material like polyethylene. When marking plastics, laser marking solutions must be equipped with the necessary fume and dust management systems.
Additional Resources on Laser Marking
- How Does Laser Marking Work in 5 Steps
- Laser Etching, Engraving & Annealing: What's the Difference?
- CO2 Vs. Fiber Laser - Which One Should You Buy?