Fiber laser cutting speeds

The Kimla company offers lasers 1, 2, 3, 4, 6, 8, 10kW, 12kW, but unfortunately there is no one universal cutting speed table that could be compared with other tables because laser power is not the only parameter that affects the speed of cutting a specific material.

The geometry of the beam is very important and how well it will be matched to a given material and thickness. And this geometry depends on the focal length of the converging lens, the focal length of the collimator and the diameter of the optical fiber and whether it is single-mode or multi-mode. The focal length of the converging lens can be 100, 125, 150, 200, 250mm and the collimator 30, 60, 75, 100mm, the optical fiber can be 20, 50, 100, 200 µm.

As you can see, the number of combinations is huge and the obtained focused beam diameters can vary from 20 to 300 µm. Just twice the diameter of the focused beam causes a fourfold increase in power density and at least theoretically accelerates the cutting.

Unfortunately, this beam cannot be reduced infinitely because its too small diameter is also bad. If the beam diameter is too small, the gap in the material being cut will be so narrow that the gas cannot blow the molten metal. The thicker the material, the problem grows and this gap should be enlarged by increasing the diameter of the focused beam.

It follows that as the material thickness increases, the speed decreases almost in the square of the thickness because the amount of material to be melted increases not only due to the increase in material thickness, but also due to the need to increase the gap width.

So let’s choose the optics configuration for the material that we will cut the most. The Kimla company, thanks to conducting detailed research and tests in the field of fiber lasers in cooperation with the largest producers of this type of sources in the world, has the opportunity to optimally select optics parameters to the customer’s needs.
It is for this reason that many customers are surprised to see our presentations, often saying that the cutting speeds of some materials are up to 2x faster than on other machines they have viewed. This is because most fiber laser manufacturers do not pay attention to it, claiming that they use a universal configuration of 100mm collimator, 200mm focus and 100um fiber. Unfortunately, as the proverb says “if something is good for everything, it sucks”.