I think I now understand what's going on here and thus how to judge "how much is enough" when it comes to the air. This is really about ember removal, and smoke to a lesser extent. What you want to see, is tiny flecks of ash being ejected from the cut. Embers which would otherwise put out more heat and smoke inside the cut. Also the ash would then reheat on a subsequent pass reducing the actual cutting action. Therefore you should see the benefit more on cuts with multiple passes. The key is focusing the air blast right down into the cut
David you asked about air pressure. Mine is just open. Although my airbrush compressor has a regulator, it needs something totally blocking the airflow to allow it build up to the set pressure, with an open needle that can't happen. By squishing the end of the outlet, you get more than enough pressure, its enough to blast any loose light particles pretty much clear of the machine. I think an aquarium pump would be enough and has the benefit of working off 12V so it can be tied into the same power source as the laser. I'll be popping down to the local pet store to take a look at what they've got.
David you asked about air pressure. Mine is just open. Although my airbrush compressor has a regulator, it needs something totally blocking the airflow to allow it build up to the set pressure, with an open needle that can't happen. By squishing the end of the outlet, you get more than enough pressure, its enough to blast any loose light particles pretty much clear of the machine. I think an aquarium pump would be enough and has the benefit of working off 12V so it can be tied into the same power source as the laser. I'll be popping down to the local pet store to take a look at what they've got.