All Laser Cutters require two additional devices which move surroundings: blower which removes Laser Cutting Air Compressor surroundings / extracts smoke from machine and air flow compressor as a source for compressed air flow for so 
called air flow 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 efficienty and fire causes charring of material / edges and may even get out of control leading to serious emergency.
Fire needs air flow to burn nonetheless it can also die in the event that you blow too hard, think about a candle in the wind. This is essentialy what atmosphere assist is usually for: compressed air is extruded straight at the laser mind in a very tight stream and is fond of where laser touches material.
Pressure of air is key variable for air support efficienty, inside our shop we discovered that optimal value is between 2 and 3.5 bar (31-50psi).
To attain required pressure compressor needs to push certain level of air through surroundings assist opening, precise volume depends upon size of the starting and desired pressure. Top quality laser cutter heads have little and finely tuned openings while cheaper chinese cutters simply blow generally direction via large holes.