Laser Engraving Basics
Laser engraving is a process where a laser beam displaces material from the surface of the part being marked. The removal of material creates depth. How deep your mark will be will depend on your laser settings, the type of material you’re marking, and the number of passes the laser makes during the mark.
Laser engraving applications
The best application for laser engraving is whenever you need a durable mark or plan on doing any post processing. For example, if you’re marking anything that’s going to experience a lot of wear and tear such as a metal pipe or drill bit, or if you’re going to be painting over the mark, you’ll want to go with laser engraving.
Laser engraving settings
When laser engraving or doing any other kind of laser mark with a fiber laser, you typically will need to adjust five settings: power, frequency, speed, hatch angles, and loop count. Understanding how these work together is key in finding the right settings for engraving.
Power is perhaps the simplest setting to understand. It is the power of your laser, usually measured in watts. The higher the wattage, the more powerful the laser. The more powerful the laser, the deeper your mark will be, assuming all your other settings are the same.
To understand frequency, we first need to understand the laser beam in a fiber laser. The laser beam is not a steady stream of energy. Instead, the laser emits light in pulses at regular intervals. Frequency determines the rate of the pulses. As frequency decreases, the number of pulses decreases, but the energy output per pulse increases. As frequency increases, the number of pulses increases, but the energy output per pulse decreases.
The speed setting determines the speed at which the laser moves across the mark. The lower the speed, the more material that is displaced. The higher the speed, the less material that is displaced.
Hatch angles are the angles at which the laser engraves the mark. Usually, these hatches leave a line pattern in your mark. If you don’t care about the look of your mark, or if those lines are desirable, this may not matter.
The last setting is the loop count. The loop count determines how many times the laser will go over your mark. More loops lead to more depth.
You can increase depth by increasing your laser’s power, decreasing the marking speed, lowering the frequency, or some combination of the three. However, doing so generates a lot of heat and can result in a dark, rough mark. You may even deform the material you’re marking.
Laser engraving grid
To show you the relationship between all these settings, we’ve created this laser engraving grid. Each mark was made with a 100-watt laser, four hatches, and a single loop.
In each row, the deepest marks are on the left. In each column, the deepest marks are on the top. But engraving isn’t just about depth. Changing the settings affected the look and quality of the marks.
Slower speeds produced darker marks. Higher speeds had a shorter cycle time and produced lighter marks. Higher frequencies produced uneven marks. How speed, frequency, and other settings affect your mark will ultimately depend on your application, but you can use these results as a guide as you adjust your settings.