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Blog on laser marking & traceability, laser cleaning and safety standards

Laser Etching: How it Works and Frequently Asked Questions

There are lots of things that have been written about laser etching. In order to help you make sense of it all, we have listed some of the most frequently asked questions (and their answers!) to help you make the right choices for your unique application.

What is Laser Etching?

Laser etching arises from the melting of the material surface. A change of phase occurs because of the high amount of energy delivered to a small surface area. The intensity (the energy per surface area) is controlled by the laser’s settings. When sufficient intensity is delivered by the laser beam, it melts the material (metals, plastics or other material targeted).

Dark and pale laser ablationFigure 1 - Microscope picture of a laser marking

How Can You Create Dark and Pale Areas with Laser Marking?

The melted material expands and re-solidifies, creating small bumps and deep crevasses on the surface. It is through these bumps and crevasses that laser experts are able to create dark and pale surfaces.

Specular diffuse entrapped reflectionsFigure 2 - b) reflections of ambient light on small bumps c) reflections of
ambient light on deep crevasses

The optical phenomenon that occurs is as follows. The reflection of ambient, regular light from surfaces with small bumps is more diffuse. They make the surface appear paler to the observer. The areas with deep crevasses tend to entrap more of the ambient light shone at them. These surfaces appear darker to the observer.

What to Expect during the Installation of a Laser Marking Machine?

  1. The laser system is adjusted so that it focuses the beam on the best possible location.

  2. The information that has to be etched on the material is uploaded to the laser controller.

  3. The laser parameters are set by our expert staff.

  4. The controllers of the laser system are connected to your existing PLC infrastructure.

  5. A few test runs are conducted.

  6. That’s it! The laser system is then fully operational.

Get in touch with our laser experts if you have any question regarding the installation of an inline laser marker in your facilities.

What Is the Difference between Laser Etching and Laser Engraving?

Laser engraving usually involves more intensity than laser etching. As a matter of fact, engraving is achieved when the material is literally vaporized. Keeping everything else similar, going for deep laser engraving (that might require several laser passes) will require more time. For more information on the factors that influence laser marking times, have a look at Laser Marking Time Estimate for Industrial Applications.

The end result of laser engraving is similar to etching: bumps and crevices create pale and dark areas, as explained earlier.

How Deep Is a Laser Etching?

Laser etching will deliver the best legibility (highest contrasts between dark marks and pale backgrounds) at around 0.5 mm (20 mils). At such a depth, you would be able to feel it to the touch and read it with the naked eye, or with a manual and automatic scanner.

What Colors Can Be Etched with a Laser?

For the purpose of industrial traceability, we tend to favor legibility over aesthetics. So dark markings on pale backgrounds are ideal.

As time is usually critical on production lines, we usually aim to provide the maximum level of contrast for the information that needs to be marked. Nevertheless, tight control of the laser’s settings may allow the creation of some shades of grey for branding purposes.

Laser annealing in two colorsFigure 3 - Example of a two tone laser marking on stainless
steel using laser annealing

For more information on the capability to render different shades of grey, you can refer to this blog post discussing stainless steel product branding in a manually loaded laser enclosure. The mechanism used in that blog post is laser annealing, which is very different from laser etching. It can only be used with titanium, stainless steel, and some other ferrous metals.

The differences between laser annealing and laser engraving are outlined in more depth here.

What Materials Can Be Laser Etched

Given that you have enough time, or that you are willing and able to use high-power laser markers, any metals can be etched with a laser. Laserax’s laser technology experts have experimented with some of the hardest and most challenging metals, including:

  • Steel

  • Stainless steel

  • Titanium

  • Aluminum

  • Zinc

  • Nickel

  • Magnesium

  • Tin

  • Lead

If you want to learn more about the laser marking of non-ferrous metal, download our white paper on the performance of laser marking for non-ferrous metals.

Laser Etching Machines

Typically a laser etching machine will include a laser, some options, and a laser safety enclosure.

  1. Lasers: Laserax has developed three types of lasers: LXQ, LXQ 3D and LXQ 3D Vision. Each is designed to carry out direct part marking on metals.

  2. Options: Our main options are the Human-Machine Interface (HMI) and the cabinet for laser source and controllers.

    1. The HMI option provides the graphical and functional interfaces required to operate the laser system manually and establish communication with other Programmed Linear Controllers.

    2. The cabinet for laser sources and controllers comes with all the equipment needed for powering the laser and other safety controls to operate the laser system. The cabinet also ensures the appropriate environment (temperature and humidity) so that the laser performs according to spec.

  3. Laser safety enclosure: Laserax’s Class 1 laser enclosures ensure the best protection for your employees. Regardless of the optical power of the laser system used. There is no other risk-mitigating procedure required when it is embedded in one of our enclosures. No personal protective equipment is required.

Laser Etching Key Points

Laser etching has been around for quite some time and from its very beginnings, Laserax has specialized in laser etching for the primary metal industry.

Laser etching is the result of the controlled fusion of metals (aluminum, stainless steel, magnesium and lead for example) and many other materials.

The laser beam fuses the metal; the metal solidifies back in a controlled manner creating small bumps and deep crevices.

Laserax's Laser Marking Solutions: Laserax’s laser etching machines are composed of a laser, some options, and a laser safety enclosure. This modular approach ensures a complete laser etching solution that is safe and reliable. What’s more: Laserax’s complete laser etching solutions provide a good quality output under any conditions and at all times.

Contact a Laser Expert

Posted by Normand Lemieux

Normand Lemieux

Normand is a well-rounded and autonomous marketing professional with a recent specialization in web marketing. He thrives to share experiences, to apply knowledge, to learn new things and get stuff done.

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