Laser engraving on metal is a process where a laser beam melts a layer of the metal substance and engraves a pre-given design.
Earlier, craftsmen did this with hand engraving which was not precise and had plenty of limitations. In modern times, there is no need to hammer metal items with crafting tools to engrave something. A laser engraver can mark the metal with letters, patterns, or even a photograph using laser technology.
However, not all metal items are handled by a single laser machine, and the low-budget laser machines cannot even mark the bare metal due to some limitations.
In this article, we will try to identify the challenges involved in metal engraving and suggest some tips and recommendations.
How does metal engraving work?
In a nutshell, metal laser engraving involves a laser beam to melt a layer of the metal workpiece to visualize any design.
However, some complexities limit the metal items engraving.
The first complexity is that the diode and the CO2 laser cannot engrave bare metal items mainly for two reasons.
First, the laser strength (or, the wavelength) of the diode and CO2 lasers are not absorbable by the bare metal, so engraving bare metal would need a fiber laser engraver.
Secondly, Bare metal reflects the laser beam in the opposite direction due to having a shiny surface. It happens because the laser beam gets reflected before metal absorbs the laser beam generated by the CO2 lasers.
How does laser marking differ from engraving?
Laser engraving is a process where a laser beam vaporizes a layer of the metal surface and visualizes any patterns or designs. In simple words, laser engraving creates a cavity on the metal surface that reveals an image at eye level.
In contrast, laser marking is a process where laser beams fully alter the metal properties to visualize any designs or diagrams without cutting or melting.
To summarize, a laser engraving would have a tangible texture on the metal surface and the laser marking would only discolor the metal surface.
The usability of both procedures is diverse. For example, laser engraving helps to etch any metal to visualize any pictures, letters or quotes whereas laser marking is used to place barcodes, QR codes, and serial numbers. Laser markings appear on the motor parts where serial numbers are laser marked.
Does all types of laser engrave metal?
Now, you may be wondering whether all types of laser can engrave metal.
To answer that, we need to learn about the laser types a little more.
To summarize, there are four different types of laser which are:
- Diode lasers
- CO2 lasers
- Fiber laser
- Hybrid lasers (diode plus infrared laser)
Technically, only the fiber lasers can engrave the metal but, a fiber laser alternative (infrared laser) can do this job on small scale.
We will explain these below.
Can diode laser engrave metal?
Technically, diode lasers cannot engrave metal, but they only engrave any temporary coating on the top of the metal layer.
Diode lasers are the most budget-friendly laser which is available at a budget starting from $400. A diode laser usually generates a laser beam with a semiconductor or, stimulated emission process.
In simple words, diode lasers are powerful to cut wood and acrylic but are not as powerful to work with metal. The main reason is that the diode lasers produce a laser wavelength of 450 nm (some may create 800 nm) whereas metal engraving would require a laser beam at a range of 1064 nm wavelength.
This is the main reason that makes a diode laser incapable of engraving a bare metal.
So, do people engrave stainless steel metal tumblers using a diode laser such as Atezr or xTool?
The answer is simple!
Diode lasers can only engrave a coated metal, which means that the laser beam does not melt the metal surface. It melts the top layer of the temporary coat which helps in visualizing the designs over the tumbler.
For example, you may look at the engraved tumbler below which ideally is not a metal engraving. It is just engraving the top layer of enamel coating.
Such tumblers or coated metal items can easily be engraved with any diode laser and this is where we get confused. You may have a look at the top lasers for engraving coated tumblers.
Can CO2 laser engrave metal?
CO2 lasers produce laser beams with carbon dioxide and other gas mediums which is a powerful laser to cut through any items.
A CO2 laser generates a wavelength of approximately 10,600 nanometers, which is in the far-infrared region of the spectrum (as shown in the earlier picture).
Because of this long wavelength, CO2 lasers are excellent for working with non-metallic materials and coated metals.
So, a CO2 laser is not ideal for engraving metal items because it generates a heavier laser beam which is not absorbed any of the metal. Moreover, the shiny texture of the metal reflects the laser beam towards the opposite direction which creates further damage.
So, How is CO2 laser used to engrave metal?
The answer is again simple. People use temporary laser marking spray or an already coated metal piece to engrave designs on metal. Ideally, CO2 lasers cannot engrave, melt, or remove any metal surface.
However, these top-notch CO2 lasers can be a must-have machine, especially for laser crafters as they cuts and engrave almost anything except metal items.
Fiber laser for metal
Fiber lasers create laser beam using the rare earth element such as erbium, ytterbium, neodymium, thulium, praseodymium, holmium or dysprosium.
Fiber lasers are the most powerful laser in this world having the capacity of cutting, welding, drilling, and engraving, particularly in the case of metals.
Fiber lasers generate laser beams at a wavelength of 1064 nm which falls under the infrared spectrum. Such laser strength is just perfect for metal engraving.
So, it can be said that fiber lasers are the ideal commercial choice for laser engraving on metal.
Not only that, a fiber laser can generate laser wavelength at different levels ranging from ultraviolet to infrared, depending on the dopant and the specific design of the laser.
However, there are two different types of fiber laser and both are capable of laser engraving on metal.
The two types are:
- MOPA fiber laser
- Q-switched fiber laser
Both are suitable for laser engraving metal items. However, MOPA fiber lasers are capable of color laser engraving on metal whereas the Q-switched lasers can only work with a single color laser marking, engraving, cutting, and welding.
Hybrid (Mixed laser) for metal
Hybrid or mixed laser technology is nothing new. it is a mixture of both diode and infrared laser which allows you to work with all material types.
The trick is that the infrared laser produces a laser beam in the infrared spectrum which can easily engrave bare metal items with its 1064 nm wavelength.
In early 2023, LaserPecker introduced such mixture of diode & infrared laser (LaserPecker 4) which further motivated the giant xTool to launch their fastest portable laser engraver – The F1 with metal engraving capability.
That was a technological hack where the manufacturer made the metal engraving easy with a portable laser module.
You may consider it as a fiber laser alternative since these lasers engrave stainless steel, gold, and other shiny metal materials.
Later on, we saw different versions of such hybrid lasers in 2023.
For instance, the xTool S1 is the first enclosed diode laser that comes with an additional infrared laser module for metal engraving at a very minimal cost.
We experimented that the xTool S1 does almost every job of a Co2 laser on a smaller scale.
Top Metal Engravers
We made a list of the top portable laser engravers that actually makes the metal laser engraving easy with portable laser machine.
How to color engrave on metal?
As described earlier, there are two types of fiber laser of which one is the MOPA fiber laser.
MOPA lasers usually perform color laser engraving in the following ways:
- Performs oxide layer creation by heating the surface with its variable frequency
- Controls oxide layer thickness using its controlled pulse rate & frequency
- Creates color using diffraction grating structure (not with the help of any pigment)
Till now, there are no alternatives to color laser engraving if you want the color without the help of any pigment.
We saw that some diode lasers such as the xTool D1 can make oxidization and brings color but these are not at the level of what MOPA fiber laser offers.
Below is a color laser engraving example we did with the MOPA fiber lasers.
What metal can you laser engrave?
Using a fiber laser or the hybrid lasers, you can laser engrave any metal. In this section, we will categorize the types of metal materials and will discuss relative challenges.
In simple words, all types of metal with a temporary coat can be laser engraved using a diode or CO2 laser. However, a fiber laser or an Infrared laser would be required to engrave bare metal having a shiny surface.
Stainless steel engraving
Engraving stainless steel is easy if you take the help of the fiber lasers as they produce laser beams at the required wavelength which is 1064 nm.
Due to the reflective nature of the stainless steel, you cannot directly place shiny stainless steel under the diode or CO2 laser as there is a risk of laser beam reflection.
If you need to use a diode or CO2 laser for stainless steel engraving, you may use a temporary laser coat spray and after the engraving is done, remove the temporary color using isopropyl alcohol.
For the best result, try the portable infrared laser/fiber laser as there is no risk of laser beam reflection.
As a reference, you can see the below picture where both of the engravings are done with the same (diode & infrared) laser.
Gold, Titanium & silver engraving
Gold, titanium, and silver cannot absorb the laser power generated from a diode or CO2 laser for the same reason of wavelength incapability.
You may use a fiber laser or an infrared laser for engraving such sensitive items.
In our prior article, we discussed how gold jewelry engraving works and possible strategies you may execute to engrave such items.
Because brass is a reflective material, you cannot engrave the bare brass using CO2 or diode lasers.
To ease out the process, there are laserable brass available in the market which is the brass with a layer of enamel pain.
When the laser engraves the top layer of the enamel, shiny golden brass starts appearing.
The only way to engrave bare brass is to use a fiber laser or an Infrared laser.
How long does laser engraving on metal last?
Laser marking or engraving is a permanent thing and there is no risk of disappearing automatically. However, there are some metals of which the engraving may disappear if it is exposed to outdoor weather. For example, uncoated metal (if it is not stainless steel) would have corrosion upon reaction with water and oxygen. Such corrosion eventually vanishes the engraving. This is why, we recommend laser engraving stainless steel which does not have any risk of corrosion due to having a zinc layer.
For more, read our detailed guidelines on laser engraving’s durability.
Steps of laser engraving on metal
For the best metal engraving result, the following steps will help you a lot.
- At the very first stage, you need to prepare the artwork. It can be a sketch, writing, or any pattern. You either need to draw it on the laser software or import it into the Lightburn or Laser GRBl.
- The next task you need to perform is to prepare your laser engraver. There might be separate settings required to engrave the artwork properly.
- After that, you need to set up the material. In some lasers, you may need to manually select the starting and ending point whereas a camera-equipped laser engraver would help you place the design from the computer screen.
- After that, start the laser engraving and wait untill the material cools down.
- In some cases, you need to perform some post-processing techniques such as cleaning with a cloth, or removing the temporary paints etc.
- After that, you are good to go with your metal laser engraving.
Should you wear a laser-safe goggle during metal engraving?
Not all lasers are Class-1 safety certified and come with a canopied protective layer. So, you should always wear the laser-safe protective goggles unless you are using laser machine such as the xTool S1, which does not need you to wear safety glasses as it is enclosed with a protective shield already.
What is the metal laser engraving alternative?
The best alternative to the laser engraving on metal is to use a diamond-drag scratch engraving machine.
It is a process where a CNC machine engraves a piece of metal dragging a diamond as per the computer given direction.
Diamond-drag etching can be a suitable alternative of the laser engraving but it does not offer you versatile work freedom like what a laser machine offers.
Metal engraving is tricky. You need to understand the terms and solutions for the challenges as described. But the entire process gets easy if you have the appropriate machine and understand the required settings and technical complexity.