Gases for Laser Beam Cutting (LBC)

Shielding / Assist Gases
The shielding gases used for LBC are predominantly N₂ and O₂. Stainless steel clean cutting uses high purity (99.8% or greater) N₂ at high pressure (200 psi and greater).

Some work has been done with lower purity membrane nitrogen (99.5%), which is boosted to the correct operating pressure. Cut surface quality and travel speed requirements dictate its suitability for use. Higher cut speeds may be achieved with the use of the lesser purity gas; however discoloration or oxidation of the cut edge can occur.

Carbon steels are cut with the assistance of high pressure O₂ (100psi). Purity levels of 99.5% or greater are recommended for highest speeds. Depending on purity, pressure and volumes, delivery of the assist gases can be in high pressure cylinders or cryogenic vessels.

Lasing Gases
CO₂ lasers utilizes a mixture of N₂/CO₂/He as the laser media which is typically supplied in a high purity grade in varying volumes depending on the equipment manufacturer. Moisture and hydrocarbon levels are critical, as poor attention to this property could result in poor lens life. Praxair laser gases are recommended by several manufacturers.