Lasers can be used for a lot of purposes. One of the best ways that they are being used is to cut metal plates. On stainless steel, aluminum plate, and mild steel, the process of laser cutting is very accurate, can yield excellent quality of cut, has a really small heat affect zone and small kerf width, and makes it possible to cut even small holes and the most intricate of shapes.
Many people are already aware that LASER is basically an acronym, which stands for Light Amplification by Stimulated Emission of Radiation. However, how can light cut through steel plates?
How CNC Laser Cutters Work
The laser beam is a column of extremely high-intensity light of one color or wavelength. As for a typical CO2 laser, this wavelength is in the light spectrum’s infrared part, so this cannot be seen by the human naked eye. This beam is just around ¾ of one inch in diameter as this is traveling from the laser resonator. It then forms the beam through the beam path of the machine.
This can bounce in various directions with the help of mirrors or beam benders before finally focusing on the plate. This focused laser beam will go through the nozzle’s bore right before hitting the plate. Compressed gas will also flow through the nozzle bore such as nitrogen or oxygen.
A special lens can also be used to focus the laser beam or even a curved mirror, and this happens in the laser cutting head. This beam must be precisely focused so that the focus spot’s shape and the energy density in the spot are perfectly consistent and round, centered within the nozzle. Through focusing the large beam down to one pinpoint, there is extreme heat density at this spot. You can think of this as using the magnifying glass to focus the rays of the sun on a leaf, and how this can start a fire. Consider focusing 6 KWatts of energy to one spot, and you can then imagine how this spot is going to get.
This high power density can result in rapid heating, complete or partial vaporizing, and melting of the material. When you use it to cut mild steel, the laser beam’s heat is sufficient to start the usual oxyfuel process of burning, with the laser cutting gas being pure oxygen, similar to any oxyfuel torch. When cutting aluminum or stainless steel, the laser beam will just melt the material, while high-pressure nitrogen will be used for blowing out the molten metal from the kerf.
On a CNC laser cutter, the head of laser cutting can be moved over to the metal plate following the shape of the desired portion, which then cuts the part out the plate. The capacitive height control system can maintain a really accurate distance between the nozzle’s end and the plate that will be cut. This distance is essential since it will determine the location of the focal point in relation to the plate’s surface. The quality of cut can also be affected.