Actually, there are a bunch of things going on (and terminology varies). What we use:
- Air assist blows on the cut and helps clear debris
- Purge air blows clean air on the optics to keep them from getting dirty
- Intake air brings fresh air into the case
- Exhaust air blows air out of the case
- Cooling air blows over things that get hot
it gets confusing. : ) one of the ways we were able to lower the cost versus a traditional laser was by combining subsystems - like the exhaust also does cooling.