All Laser Cutters require two additional devices which move air flow: blower which removes air flow / extracts smoke from machine and air compressor as a source for compressed atmosphere for so called surroundings assist.
Laser cuts by high temperature, very high high temperature focused in tight beam. Side items of high temperature are smoke and fire, both aren’t welcomed addition, smoke disperses laser reducint it’s Laser Cutting Air Compressor efficienty and fire causes charring of material / edges 
and may even escape control leading to serious emergency.
Fire needs surroundings to burn nonetheless it can also die if you blow too hard, think about a candle in the wind. This is essentialy what air assist can be for: compressed surroundings is extruded directly at the laser mind in a very restricted stream and is directed at the place where laser touches material.
Pressure of atmosphere is key adjustable for air help efficienty, in our shop we discovered that optimal value is between 2 and 3.5 bar (31-50psi).
To accomplish required pressure compressor must push certain level of air through surroundings assist opening, precise volume depends upon size of the opening and desired pressure. Top quality laser beam cutter heads have little and finely tuned openings while cheaper chinese cutters just blow in general direction via huge holes.