Laser Cutting: Assist Gas

In many instances, the laser's ability to cut can be further improved by selecting the proper assist gas. Oxygen assist gas serves two purposes: to assist in combustion, and to blow the debris or molten metal away from the kerf.  Nitrogen is an inert gas and it serves to discharge the molten metal away from the kerf.  When cutting with Nitrogen the energy from the laser is the only tool used in the thermal process of melting/cutting the material.  In addition to Nitrogen and Oxygen there are certain applications where Air, Argon and a blended mixture of N2 and O2 can achieve greater speeds and improved edge quality while simultaneously eliminating dross/slag. All things being equal… generally speaking compressed air produces faster cuts than nitrogen in mild steel, stainless steel, and aluminum. Significantly higher gains of 20% - 40% can be realized by blending N2 and O2.