All Laser Cutters require two additional devices which move air flow: blower which removes air / extracts smoke from machine and 
air flow compressor as a source for compressed air flow for so called surroundings assist.
Laser cuts by heat, very high heat focused in tight beam. Side products of high temperature are smoke and fire, both are not welcomed addition, smoke disperses laser beam reducint it’s efficienty and fire causes charring of material / edges and will even get out of control causing serious emergency.
Fire needs air flow to burn but it can also die in the event that you blow too hard, think about a candle in the wind. That is essentialy what surroundings assist can be for: compressed atmosphere is extruded straight at the laser head in a very limited stream and is fond of where laser touches material.
Laser Cutting Air Compressor Pressure of surroundings is key adjustable for air support efficienty, in our shop we discovered that optimal value is between 2 and 3.5 bar (31-50psi).
To achieve required pressure compressor must push certain level of air through air assist opening, specific volume depends upon size of the opening and desired pressure. High quality laser beam cutter heads have little and finely tuned openings while cheaper chinese cutters simply blow in general direction via huge holes.