Sublimation Cutting

Sublimation cutting: the laser beam vaporizes and burns the material. The vapor pressure expels the slag from the kerf.

In this process, the idea is to use the laser to vaporize the material with as little melting occurring as possible. In the kerf, the material vapor creates a high pressure that expels the molten material from the top and bottom of the kerf.
The process gas – nitrogen, argon, or helium – serves solely to shield the cut surfaces from the environment. It ensures that the cut edges remain oxide free. For this reason, a gas pressure of 1 to 3 bar is sufficient.
More energy is needed to vaporize metal than to melt it. For this reason, sublimation cutting requires high laser power and is slower than other cutting processes. At the same time, however, it produces high-quality cuts. This process is rarely employed in sheet metal fabrication. Its use, however, becomes attractive in applications involving particularly delicate cutting work. Such applications include the production of stents.