All Laser Cutters need two additional devices which move atmosphere: blower which removes atmosphere / extracts smoke from machine and air compressor as a source for compressed atmosphere for so called atmosphere assist.
Why and How
Laser cuts by warmth, very high high temperature focused in tight beam. Side products of high temperature are smoke and fire, both aren’t welcomed addition, smoke disperses 
laser beam reducint it’s efficienty and fire causes charring of material / edges and can even escape control leading to serious emergency.
Fire needs air to burn but it will also die if you blow too hard, think about a candle in the wind. That is essentialy what atmosphere assist is definitely for: compressed surroundings is extruded straight at the laser head in a very limited stream and is directed at the place where laser touches material.
Pressure and volume of air
Pressure of air is essential variable for air help efficienty, in our shop we discovered that Air Compressor For Tire Production Equipment optimal worth is between 2 and 3.5 bar (31-50psi).
To accomplish required pressure compressor needs to push certain level of air through surroundings assist opening, precise 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 just blow generally direction via large holes.
Proper compressor
When choosing compressor you should consider if it will be able to constantly provide desired pressure and volume of air. Small airbrush compressors small compressors boast impressive pressure figures but really poor flow rates adequate limited to airbrush pistols. Actually if small compressor can push enough air it’ll likely overheat in short while.