How Does Laser Cutting Work? – Elena

Why use laser cutting

There are many purposes. One way they are used is to cut metal plates. The laser cutting process is very precise on low carbon steel, stainless steel and aluminum plates, resulting in excellent cutting quality. Its notch width is very small, solo can affects a small zona. In addition, it can cut very complex shapes and small holes.

Most people already know that the word “LASER” is actually an abbreviation for amplified by radiation-excited light. But how does the light penetrate the steel plate?

How it works

A laser beam is a series of very high-intensity light with a single wavelength or color. For a typical CO2 laser, this wavelength is in the infrared part of the spectrum. So it is invisible to the human eye. When the beam propagates from the laser resonator, the diameter is only 3/4 inch in diameter. It creates a light beam through the light path of the machine. Before finally focusing on the board, we reflecte many mirrors or “beam benders”  in different directions. The focused laser beam passes through the orifice of the nozzle before hitting the plate. Also flowing through the nozzle hole is a compressed gas, such as oxygen or nitrogen.

In a laser cutting head, through a special lens or curved mirror can focusing the laser beam. The purpose is to make the shape of the focal point and the energy density in the focal point completely circular and consistent, and located in the center of the nozzle. By focusing a large beam to a single precise point, the heat density at that point is extremely high. Consider using a magnifying glass to focus the sun’s rays on the leaves and how to trigger a fire. Now consider concentrating 6 kW of energy at a point, and you can imagine how hot that point will become.

High power density results in rapid heating, melting and partial or complete evaporation of the material. When cutting mild steel, the heat of the laser beam is sufficient to initiate the typical “oxy-fuel” combustion process, and the laser cutting gas will be pure oxygen like an oxygen burner. When cutting stainless steel or aluminum, the laser beam will only melt the material. We usually use high pressure nitrogen to blow molten metal out of the slit.

other factors

On a laser cutting machine, moving the laser cutting head on the metal plate in the shape of the required part, thereby cutting the part from the metal plate. The capacitive height control system maintains a very precise distance between the end of the nozzle and the plate being cut. This distance is important because it determines the position of the focal point relative to the surface of the plate. Raising or lowering the focus from different directions can affect the quality of the cut. Above the surface of the board, at or below the surface.

There are many other parameters that also affect the quality of the cut. If we can control everything correctly, laser cutting will be a stable, reliable and very precise cutting process.