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Laser Cutting |
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Laser cutting is divided into three processes: oxygen cutting, nitrogen cutting (also called clean cutting) and sublimation cutting. Linde personnel are expert in all three.
Laser cutting plays a dominant role in metal processing. High-power beam sources, fiber delivery and highly automated peripheral material handling systems allow for high cutting speeds, extreme precision and high productivity in both 2D and 3D applications.
Linde has thoroughly researched laser cutting, from material influences to the impact of supersonic cutting nozzles. This research led to the LASOX process (discussed below), among others. |
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| When cutting with oxygen, material is burned and vaporized when heated by the laser beam to ignition temperature. The reaction between the oxygen and the metal creates additional energy in the form of heat, supporting the cutting process. These exothermic reactions explain why oxygen can penetrate thick and reflective material; however, they need to be controlled, since violent reactions can occur and not only reduce cut quality but affect workplace safety.
Whenever oxygen is used as a cutting gas for mild steel, the thicker the material is, the lower the gas flow should be. Cutting with oxygen leaves a layer of oxide on the cut edge, causing a reduction in alloying elements; it is therefore predominantly used to cut carbon steels.
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| When cutting with nitrogen (or any other inert gas), material is melted solely by the laser power and blown out of the cut kerf by the gas jet’s kinetic energy. Since these gases do not react with molten metal and the material is not overheated by exothermic reactions, laser power and cutting gas pressure are much higher than with oxygen cutting.
In nitrogen cutting, higher pressures are therefore required as material thickness increases. Cutting with nitrogen is used often with aluminum and stainless steel, to achieve good edge quality and maintain corrosion resistance. It is also applied to carbon steels whenever painting or powder-coating is later required.
In sublimation cutting, the solid material is converted into vapor without passing through a liquid phase (i.e., when cutting paper, wood or certain fabrics).
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| LASOX technology uses a cutting head that directs a laser beam through the center of a gas nozzle. The laser beam preheats the steel workpiece to ignition temperature, and a high-speed oxygen jet targeted at the beam's footprint oxidizes the steel in a narrow cut. The head is mechanically moved relative to the plate, and the workpiece is severed as the force of a supersonic stream of oxygen expels molten metal and metal oxides from the kerf.
The above discussed principles are summarized in Linde’s Facts About: Laser Cutting Brochure. For more information on how Linde can optimize your laser-cutting operations, be sure to Contact Us.
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