All Laser Cutters need two additional gadgets which move air flow: blower which removes surroundings / extracts smoke from machine and air compressor as a https://www.ever-power.net/?s=laser+cutting+air+compressor&post_type=product source for compressed atmosphere for so called air assist.
Why and How
Laser cuts by temperature, very high high temperature focused in tight beam. Side items of high heat 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 may even escape control leading to serious emergency.
Fire needs surroundings 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 is definitely for: compressed atmosphere is extruded directly at the laser head in a very restricted stream and is fond of the place where laser touches material.
Pressure and level of air
Pressure of surroundings is essential 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 atmosphere assist opening, specific 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 just blow in general direction via large holes.
Proper compressor
When choosing compressor you need to consider if it will be able to constantly provide desired pressure and volume of air. Little airbrush compressors small compressors boast impressive pressure figures but really poor flow rates enough only for airbrush pistols. Actually if small compressor can push enough air it will likely overheat in couple of minutes.