Air Assist Dynamics: Cutting vs. Engraving

What Air Assist Does

Air assist directs compressed air at the focal point. It clears combustion gases from the cut path, cools the material surface to reduce char, and blows debris out of the kerf before it re-deposits.

Cutting: High Pressure

For cutting use maximum air pressure (20–60 PSI). High-pressure air blows molten material and combustion gases clear immediately. Low air assist during cutting means more char, wider kerf, and risk of ignition.

Coaxial nozzles are most effective for cutting — they direct air exactly where the laser is working at all times.

Engraving: Low or No Pressure

For engraving, high-pressure air cools the surface too aggressively, reducing depth, and blows debris into previously engraved areas. Reduce air assist to 5–15 PSI for engraving, or disable it entirely for fine photographic engraving on wood.

Exception: acrylic engraving benefits from moderate air assist to prevent haze and melting at engraved edges.

Nozzle Design

A 1.5–2mm nozzle ID concentrates airflow for cutting. A 3–4mm nozzle provides gentler, wider coverage better suited to engraving. For production, consider two air lines switched by a solenoid valve controlled by LightBurn's air assist layer setting.

Compressor Sizing

Minimum 1–2 gallon tank for occasional use. For production, 6+ gallons with a regulator and inline moisture separator. A desiccant inline filter prevents moisture from depositing on lenses.