I can see that I maybe need some kind of air cooling to my

I can see that I maybe need some kind of air cooling to my laser cutter? Anyone can help how to do that?
AND I have no idea how to adjust the focal lens - can anyone explain?

You definitely need water cooling for your Laser, otherwise it is dead pretty quickly.

For the chamber, you might want some air-exhaust system to keep it smoke-free (and connect that to some filter or through a window).

You usually don’t adjust the focal lens itself, but the distance between the lens and the stuff to cut; there are standard distances (one typical one is 7cm); once you have determined that, it is useful to make a template: a piece of wood or acrylic that you use as measurement gauge between the laser and the item to cut.

Oh, I have water-cooling. I have a small pump cooling with water. But they said I need Air-cooling to be able to cut in plywood.

Moving air is needed to get the smoke out of the cutting area. First it makes sure that the laser has free sight and second it helps that the lens is not sudded up.

@Nikolaj_Hygebjerg I believe more accurately it would be Air Assist. Basically a nozzle that goes over the lens thats forces air down towards the work piece. I’m not 100% certain why it helps, but my theory is it clears smoke from the beam path, allowing the full power of it to reach firther into the material.

It just makes sure to not fog the lens over time. Plastic residue is nasty, so you might need to clean or replace the lens often otherwise.

I clean my optics once a day, at the very least. I clean them immediately after cutting something especially smoky or nasty.

lint free wipes and acetone or denatured alcohol is what I use.