I've just bought my K40, and I'm working on upgrading it with air-assist.

Lasers
,
1

I’ve just bought my K40, and I’m working on upgrading it with air-assist. (I’ve ordered the new head from lightobject)
My question is, what airpump/compressor should I use?
Is the pressure important, or only the air-flow?
Is the air-assist only helps cleaning the lens clear, or should it also help the cutting in some way? (cooling the surface maybe)

I want to cut nylon webbing. I’ve read in a webpage, that they are using 25w co2 + 10 psi air assist, for similar jobs (http://www.synrad.com/search_apps/application_briefs/118-3.htm)

Do I really need 10 psi?

I’d like a low-cost solution, so I’ve found 3 options, they are at the same price:

  • Hailea ACO-328 air compressor (made for aquariums/ponds) - low pressure (maybe 5-6 psi if I’m correct), high airflow - 70 liters/min
  • small airbrush compressor with or without air tank (small - 3 liters) - max 60 psi (with regulator, so I can go down to 10 psi), but maximum airflow is 23 liters/min
    -Or should I go for some “real” compressor, with bigger tank (20l), bigger max pressure (110 psi, so it must be regulated). It would be big and noisy…
2

If you get a big compressor, you’ll need to get a filter-drier, or you’ll find that water will condense in the line and spray on your optics (bad).

A dedicated compressor (no tank), located close to the machine won’t have this problem because air won’t drop in temperature between the compressor and the cutter.
I started out with a real compressor (and needle valve to make 20m/s through my air-assist nozzle); that velocity is roughly 42 liters/min. The pressure required to make it through the tubing is going to be ~4 PSI (I calculated as 5m of 1/8" tube and it was 2psi, but I’ll say 4 to not worry about it). So I’m thinking large aquarium pump.

3

It does help the surface too – if you’re running at low speeds, cutting Birch ply (I cut 40W power 5mm/s, 1 pass), if you don’t run air-assist (or it’s too small), you’ll have a flame right under your optics. 20m/s of air blows it out for a nice, clean cut (still gotta use tape). My air assist has a 1/4" hole in the tip (I printed mine), so all the calcs are based on that.
Cutting Nylon is probably even better-- nylon tends to melt according to many other pages (https://www.pololu.com/docs/0J24/3).

4

Thanks, however finally I’ve bought the “big” compressor. I’ll need to buy a water separator, and I hope it will work as I think :wink: