buildlog.net

All,

I was talking to a collegue at work about this project and he reccomended using nitrogen or CO2 as the sweep gas for the laser when cutting woods. Has anybody ever heard of doing that? My gut instinct tells me that it may help reduce charing some, but it won't eliminate it wood contains a whole lot of oxygen and regardless of the environment it will blacken when heated, even in a vacuum. I have a CO2 tank and could probably find a mass flow controller to supply it. I think I have one laying around from my old business that I could jurry rig. The other advantage of inert gas is a big fire hazard reduction. However, my concern about using CO2 is the laser light making the gas hot. IR is absorbed by CO2 so I was thinking of using nitrogen instead, but that involves more expense for me to try as I don't have a nitrogen cylinder anymore. I have the regulators, but not the right tank. Do you think it is worth a try with CO2 or nitrogen?

It is very common to use an inert gas for laser cutting operations. With wood, it may be a marginal return on the investment, but with some other applications, it may have big advantages. Paper, leather, cork, and other materials should have greatly reduced charring.

What gas would be the best to use? I have CO2 cylindars already and they are very cheap, but I was concerned about the IR absorbance of the gas... I don't know what it will do in such a strong and concentrated beam. Nitrogen would be the next cheapest thing.

i've only ever heard of using nitrogen...it seems to be popular...but i couldnt find anyone in the DIY / Open-Source community actually using it. At one point i was looking into it to help with paper scorching.

On the other hand imagine what you could cut with an oxygen assist!

CO2 is not inert. A mass flow controller is insane overkill, a needle valve will do. Or just a straight connection to the regulator.

Don't even think about using oxygen without fire detection in the cabinet.