A laser cutting machine depends on a steady supply of clean, dry assist gas to blow molten metal from the cut. If pressure fluctuates or the air carries water and oil, the edge quality, speed and lens life all suffer.
Assist gas options
- Nitrogen — clean, oxidation-free edges for stainless steel and aluminium, at higher running cost
- Oxygen — faster cutting of carbon steel with some edge oxidation
- Compressed air — the most economical option for thin sheet and general cutting
Compressed air is attractive because it is produced on site, but it must be dried to a low dew point and filtered to prevent moisture and oil from degrading the optics and the cut.
Sizing the compressor
Add the air demand of the cutting head plus any assist systems that run together. Most small and medium laser cutters need 1.0–2.5 m³/min at 7–16 bar depending on nozzle size and material thickness. A dedicated high-pressure screw compressor with a refrigerated or adsorption dryer and coalescing filters is the standard configuration.
Protecting cut quality
Fit a receiver tank to damp pressure pulses and size the dryer for the compressor output. Regular filter-element replacement is essential; a clogged filter starves the nozzle and produces dross and burrs.