How on earth was this done? Multiple fiber laser passes?

[Neville Stewart]

This is an anodized or perhaps cerakote AR 15 lower. It looks like it has about three depths there.
image.jpg

[Scott Shepherd]

Looks like a fiber laser to me. Doesn't look that sharp around the letters, which is what can happen when you have to take a bazillion passes to get that depth.

[Neville Stewart]

Thanks Scott, kinda guessed fiber. I see the loss of detail but those letters are probably only 1mm in height. Still, a pretty cool effect, delicate on a gun though.

[Dan Hintz]

Looks like a fiber laser to me. Doesn't look that sharp around the letters, which is what can happen when you have to take a bazillion passes to get that depth.

I would blame the lack of sharpness on a Chinese-quality galvo rather than the number of passes it took to get the depth. Those cheap galvos aren't precision instruments, so when you push them for speed (which you need with that many passes to get the job done in a reasonable timeframe), the repeatability of positioning drops like a rock.

[Scott Shepherd]

I wonder if that was done on a Galvo or a gantry fiber. Seems like it would take a long time either way as that's a lot of metal to remove.

[Dan Hintz]

I wonder if that was done on a Galvo or a gantry fiber. Seems like it would take a long time either way as that's a lot of metal to remove.

No lie, that would take the better part of a day on a gantry unit. A galvo might have it finished in 20-30 minutes. (Depending upon wattage, of course). Either is possible, but galvo is the only realistic way if these are being done as part of a (profitable) business.

[Kev Williams]

I'm going with acid. The bottom of the image is mottled. Lasers don't do mottled, sandblasting is not that coarse, but acid does-

[Dan Hintz]

Lasers don't do mottled

Sure they do... it all depends upon the waveform selected for the final passes. You can make it mottled or you can make it (nearly) baby's butt smooth. and acid would do some serious undercutting at that depth.

[matthew knott]

Is definitely a fibre, probably a 20-30 watt but the power is anyones guess, the detail in the character is quite normal for deep engraving, it normally needs a quick clean with a shot blaster to remove it, its just burn slag from the removal process. Chinese galvos are actually very good now days Dan and only start to fall over at extreme speeds, like over 6000mm/Second, for deep material removal you would probably be going no faster than 600mm/Second. You can get a smooth bottom but it means using trick angles for the fill of each pass and also have a clean up pass routine after you have taken about 0.03mm of material away. I could do this job on my 50 watt laser in around 15 minutes, a 20 watt mike take around an hour to complete.
I think it looks kind of cool

[Kev Williams]

interesting on the mottled bottom, I've never seen any fiber engraved finish aside from the typical 'record groove'. But then, I haven't seen all that many.

I'd love to see pics of other similar engraving done by fiber...

[Bruce Boone]

yhst-94738257750630_2269_14259212.gif
This is done by an 80 watt YAG on titanium. The pass has a randomizing function to get the mottled look. It could be done with a lot less power to get an even gray look as well. You specify the frequency and angles and power and a few other variables to get the look you want.