Understanding Your Laser Settings

A laser’s power is the amount of energy the laser beam can output. It is usually measured in watts (W). Laser marking software usually gives operators control over how much power a laser outputs, up to the maximum power available. A 20W laser can output between 1W and 20W, for example.

The power of a laser can affect its behavior and applications. For example, a higher-wattage laser can engrave hard metals faster than a laser using a lower wattage. On the other hand, a lower-wattage laser can safely mark a softer, more delicate metal whereas a high-wattage laser might burn it.

Typically, the laser in a laser marking machine doesn’t emit a continuous beam of light. Instead, it releases pulses of light so quickly that they are measured in thousands of pulses per second (kilohertz - khz). Changing the frequency affects how often a laser pulse impacts the part being marked.

There is an inverse relationship between the frequency and the power of each pulse. Imagine you’re bending a water hose so that no water is coming out of the nozzle. Water builds up behind the bend and when you unbend the hose, water gushes through. The more frequently you bend and unbend the hose, the less the water builds up and less water gushes through each time.

When you bend and unbend the hose less frequently, more water builds up and gushes through each time. Similarly, lower pulse frequencies are more likely to displace material because each pulse has more energy built up in each pulse. Higher frequencies are more likely to just heat the surface of a material instead of displacing it because there is less energy in each pulse.

Because of this, a higher frequency is generally a better starting point for marking applications that require little to no depth while a lower frequency may work better if you need depth in your mark.

As you set up your laser marking parameters, keep in mind that generally, laser marking is about energy and heat. The more energy a spot on a part receives, the hotter that spot gets, potentially displacing more material. While increasing power may seem like the way to increase the depth of a mark, a slower speed and/or lower frequency may produce a similar if not better mark. As such, your laser’s power, frequency, and speed should be carefully adjusted and tested for each material and application to achieve the desired results.