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What is Laser Marking?

Brendan McGuigan
Brendan McGuigan

Laser marking is used as a way of permanently marking a physical item for tracking, either for security of quality control reasons. Rather than using a vibrating or rotating tool to engrave a mark on the item, a high-powered laser is used.

While most forms of engraving result in a loss of some of the marked material when it is etched away, laser marking results in essentially no loss of material. Instead, the laser is used to create a shift in the color of the material, creating a visible, virtually indestructible mark with minimal real impact to the item.

Most plastics can be laser marked, and the process is used on everything from identification badges to complimentary pens. Given its indelible nature, laser marking is an ideal choice for bar codes and other forms of inconspicuous tracking.

An added benefit of laser marking is environmental: with no inks or solvents used, the impact is very minimal. As costs lower, this factor becomes a decisive one for many environmentally-conscious companies and individuals.

Some companies use laser marking to burn logos into wood or metal.
Some companies use laser marking to burn logos into wood or metal.

There are three main results of laser marking, depending on the material affected and the laser used to mark the item. Charring occurs when the absorbed energy heats up the surrounding material enough to create a slight degradation, resulting in a black mark. Foaming occurs in the case of plastic marking when the surrounding temperature is raised enough to cause the polymers to degrade to gasses, forming small bubbles. Ablation occurs when the material becomes extremely hot and the plastic degrades completely, leaving a clean depression.

One particularly popular use of laser marking in recent years has been in the bar-coding and certifying of diamonds. By using extremely tight beams at very low wavelengths well in the deep ultraviolet range, codes can be inscribed in the diamonds with virtually no external damage. A 193nm Excimer laser is used to create a mark so small as to entirely invisible to the naked eye, and non-intrusive enough to make the chances of cracking or chipping close to zero.

Laser marking can be used on all sorts of substrates including wood, metal, and fiberglass. In addition to bar codes and other tracking info, many companies use laser marking to add their logo to parts or products. An added benefit is that the markings can be applied in difficult to reach areas; all that is required is a direct line-of-sight for the laser beam.

Discussion Comments

stl156

@titans62 - I know that some watches companies use laser marking on metal faces for their watches, so it is possible. You are probably right, though, that if it is on the back of the watch it has been engraved.

I was looking through a cookware website the other day, and I saw a pan that could be laser marked with certain designs. I know when I bought my IPod, there was the option to have your initials or some sort of sentence put on the back of it. I'm betting that would probably have been laser marked. I'm still not sure what an example of laser marking on plastic would be.

I wonder if there would be a business opportunity in having a laser marking service where people could pay you to put markings on their things. It seems like it might be a good idea for construction companies that might have a problem with tools getting stolen. Laser marking equipment would probably be too expensive to do something like that, though.

titans62

@cardsfan27 - I am wondering, too, exactly what something that has been laser marked would look like.

I know that I have seen things before they say they were engraved with a laser, but I don't think that is the same thing as what this article is describing. On the back of my watch, I know the writing is supposedly done with a laser. You can feel the texture of it, though. It isn't just a smooth surface.

cardsfan27

@ - To go along with your question, I wonder if you get some sort of identification number when you buy a diamond that has been marked. Something like a certificate of authenticity that you could use to prove that a diamond was yours if it ever got stolen. I have never bought any diamonds before, so I don't have any experience in this area.

For companies that use this system, what does a laser marking machine even look like? Are there different types of lasers depending on what kind of product you are marking? Besides diamonds, what are some other products that might be laser marked? I'm sure I have seen laser marked barcodes and such, but just didn't know what I would looking at. How do you ID something that has been printed with a laser?

JimmyT

Wow, that is really neat that they can use a laser to put a special mark on diamonds. I'm sure that once the laser mark is on them it is nearly impossible to get rid of it, too. That would be a great way to make sure diamonds were legitimate or identify one that had been stolen.

Would they still put laser marks on very high priced diamonds, or would that be considered to lower the price, since there would be a mark on it?

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    • Some companies use laser marking to burn logos into wood or metal.
      By: Paul Bodea
      Some companies use laser marking to burn logos into wood or metal.