Why Laser Cutting Machines Require Auxiliary Gas？

During laser cutting, auxiliary gas serves as an indispensable key element, fulfilling several critical functions.

1. Removing Molten Residue to Ensure Cutting Quality

When laser cutting, materials rapidly melt or even vaporise under the high energy of the laser beam. At this stage, the auxiliary gas acts like a 'cleaning brush', using high-speed gas flow to expel molten and vaporised residues from the cutting seam. Without this purging action, residues would solidify on the cut surface, forming defects such as burrs and slag inclusions that severely compromise surface finish and dimensional accuracy. For instance, when cutting stainless steel, employing suitable auxiliary gases effectively removes molten slag, yielding smooth, flat edges.

2. Cooling the Material to Minimise the Heat-Affected Zone

Heat generated during laser cutting conducts into surrounding material, forming a heat-affected zone that alters material properties-such as reduced hardness and diminished toughness. While purging molten slag, the auxiliary gas also cools adjacent material, minimising the extent and severity of the heat-affected zone. For carbon steel cutting, judicious use of auxiliary gas prevents overheating damage to mechanical properties, preserving post-cut strength and toughness.

3. Enhancing Cutting Capability and Efficiency

Auxiliary gases can chemically interact with the material to further enhance cutting performance. When oxygen is employed as the auxiliary gas for carbon steel cutting, it undergoes vigorous oxidation reactions with carbon at high temperatures, releasing substantial heat. This additional thermal energy accelerates material melting and vaporisation, significantly increasing cutting speed. Concurrently, this oxidation reaction produces narrower kerfs, minimising material wastage.

4. Protecting optical components and extending equipment lifespan

During laser cutting, fumes and spatter generated by the process may rebound upwards, contaminating optical components such as focusing lenses. The gas flow barrier formed by the auxiliary gas effectively blocks these contaminants, safeguarding optical elements from damage. This extends equipment service life and reduces maintenance costs.