How Does Laser Marking Work?
Laser marking is a popular, efficient, and highly safe process that has allowed for a wide range of markings to be created on various materials around the world. This may be for aesthetic reasons, or perhaps to help label products, it has been adopted by many industries around the world, such as the aerospace or automotive (including e-mobility) sectors.
As one of the most important processes that our fiber lasers complete, we thought it would be worthwhile sharing more detailed information on the use of a laser marking machine, its applications, and how laser marking works.
What is the marking process?
As its name alludes to, it is simply the placing of a mark on a material using a focused laser beam. This can be done on a number of materials, such as metals, stones, plastics, and rubbers. This mark will be left at surface level permanently.
It is important to note that while this process has many similarities to laser engraving, it has enough differences to be considered a process in its own right. The main difference is that the aim of laser engraving is to leave a deep engraving, while laser marking systems leave a mark at surface level.
The marking process, which can also be referred to as laser “coloration”(the color of the marking will be up to the original color of the item to be marked), is generally used for things such as bar codes, QR codes, logos or other types of identification markings. While laser engraving can also be used for this if the identification mark needs to be deeper, engraving is most typically used for personalization and customization reasons.
How does the process work?
So, now that you know a little more about the process and what it’s used for, we want to examine how laser marking works. It’s important to note at the beginning that this is a high-speed and high-precision process.
It works quickly, effectively, and safely, leaving a high-quality mark on whichever material that it is working with. This may be flat surfaces, flexible materials, or even complex shapes as laser marking takes place without any contact.
To laser mark, one directs a focused laser beam onto the surface of the material that they are working with, and the heat of the beam will generate a contrast between the affected area and the surrounding material.
Essentially, the beam oxidizes the area underneath the surface of the area that it is targeting, causing it to change color. The majority of markings will turn black, but some surfaces will cause a color change instead.
A big allure with this process is that the surface layer of a material, and the material itself, isn’t damaged in any way or made uneven. No layers are removed, they are simply adapted through localized heating.
What are the different types of marking?
There are different types of laser marking machine processes, each with its own unique array of properties. We’ve covered each of these briefly below.
Annealing
The annealing process is reserved for metals. While the majority of marks produced are black, the oxidization that occurs beneath the surface with annealing will result in a color change. Frequently used for marking iron, the color will be dependent on the level of heat, but typical colors are yellow, red, and green.
“Color” marking
With laser “color” marking, the heat of the beam will cause a chemical reaction. The aim here is to create a variety of different color shades on the material that is being worked with. The shade that will be produced is dependent on the material’s chemical composition. “Color” marking is particularly popular within the jeweler industry.
Engraving
As discussed earlier, laser engraving is a process that is sufficiently different from marking to be considered an application in its own right. However, the two are often compared together, so it’s worth touching on here.
With laser engraving, the surface layer of material will be melted and vaporized by the beam, leaving a deep engraving beneath. The level of depth can be controlled depending on the user’s requirements.
Foaming
With foaming, the laser beam will melt the area that it is working with, causing gas bubbles that will reflect the light. The areas that have been marked, therefore, will be lighter than the areas that haven’t.
Carbonizing
Carbonizing works in a similar way as foaming, with the end result helping to produce strong contrasts on typically bright surfaces. The laser will heat up the area it is working with, emitting gases such as oxygen or hydrogen. In its wake will be left a dark area with a much higher level of carbon concentration.
Scribing
This is where a message is scribed on the material. This includes hallmarks and inscribing diamonds.
