this post was submitted on 21 Dec 2023
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[–] eldoom@lemm.ee 4 points 6 months ago (1 children)

CNC laser operator here.

I don't know about these lower power lasers so I may be wrong. With the lasers I've used (200-2000W), the air/oxygen is used to create a superheated jacket of gas around the laser which allows it to cut a nice smooth edge. It also has the added benefit of blowing away the slag/dross that's created.

When we cut more temperature sensitive materials like aluminum and stainless we use nitrogen, which cools the material. This creates a pretty jagged deal with the dross that you gotta sand off but it prevents blowouts and really creates a nice edge if you get the pressure dialed in just right.

[–] wjrii@kbin.social 3 points 6 months ago* (last edited 6 months ago) (1 children)

You could well be right, and I don't doubt for a second that you know your stuff. What I've heard more often on the low powered diodes is that it just prevents the smoke from blocking the laser's wattage, which is already in short supply, and keeps it from fouling the optics.

Frankly, so far the whole thing only works about as well as the big-ass oscillating fan I had blasting at the laser and workpiece, but it's much nicer to live with, especially now that winter is here.

[–] eldoom@lemm.ee 3 points 6 months ago

Oh yeah that's a pretty solid benefit right there. I swear the oddest things will block them from cutting. I didn't even consider the smoke diffusing the beam.

Like the most powerful laser I've used won't cut through a paper sticker or even the residue but it'll cut through .75" steel like it's nothing.

The optics is a big deal too. On the big ones everything is pretty reasonably sized and they're still a pain to clean. I can't imagine what it's like with those tiny ones. Also, those larger lasers lenses are really commonly coated in thorium and a speck gets on there it's going to superheat and vaporize a lot of the lense. Pretty damn dangerous to be around lol!