Diode laser anodized aluminum "etching" discoloration

[XEMON]

Hello MCB,

I've been looking at laser "engraver" lately.

In an ideal world, I would get a K40/50 and go to town, but the cooling system and lack of being able to regulate power output during the operation without a board upgrade that cost half of the price of the machine is putting me off a bit.
the size of the installation is rough as I have very limited space ...

So I've been looking at diode laser, they seam much more versatile,but much less powerful.

I would be considering the ortur type, probably the higher power unit. But I have a hard time finding some answers before I do the jump.
Can those diode laser attack the dye in the anodized aluminum?

Anyone got one of those and would share their experience?

Thanks MCB,
X

[DocsMachine]

Okay, a decent diode laser can, I'm told, mark anodizing.

The big drawback to a diode laser is that they're extremely dangerous to eyes. A K40 or other tube laser produces an infrared beam- invisible to the naked eye, and the frequency is stopped by nearly anything. Glass, acrylic, polycarbonate, etc. Basically standard eyeglasses or typical shop safety glasses are sufficient.

Diode lasers put out ultraviolet, and in a frequency that can give you permanent eye damage from a reflection. For these, you MUST have the laser enclosed in something that stops that particular frequency, AND, have safety glasses rated for it as well.

And a LOT of the cheap glasses you get off of eBay or Alibaba or the like, are, like everything else, fake. Just orange-tinted plastic. A good set'll run ya $60 or more- mine cost $95.

I picked up a... I think it was a 15W rated diode a couple years ago, intending to mount it to my Shapeoko, or one of those cheap little bolt-together eBay quote-unquote "milling machines". First, I was told that it's actually an overdriven 7W laser, and probably only has a duty cycle measure in seconds at full power. Second, I was warned about the eye safety thing, and while that's not something that can't be worked around, I thought that, being a total noob at the time, it was more risk that I really liked.

I eventually got a K40, and after a few stupid mistakes- yes, even I can make them - got it up and running. It works great, although I admit it took some fiddling to get it there.

Doc.

[boarder2k7]

Yeah +1 to the eye safety. The open gantry machines terrify me. Even just looking at the point of light without any reflection can be dangerous, it probably isn't even a good idea with a CO2 laser to be honest. Very true about the CO2 laser being blocked by pretty much anything though. Even your cornea will block it before it messes up your retina. As far as eyes go, the cornea is much more reparable than the retina is.

[bellicose]

In the world of lasers, you definitely get what you pay for. A lot of those machines you will have to tinker with both mechanically and on the software to produce good results. It's too bad good CO2 lasers are so stinking expensive. I have exclusive access to a Universal VLS 4.60 at my job and it is a work horse out of the box (well crate, it's huge). If I had to get some system with my own money, it would be a smaller setup like a glowforge. Tons of support in a large community.

[XEMON]

Thanks everyone for the input.

I can work with the safety issues of the open gantry (make a box) but it's not worth it if it can barely do what I need ...

Seams like I'll have to wait till am able to get setup for a K40 or alike ...

How do you manage the cooling system for a machine you don't use every day?
I ran water-cooled tig system, but they ran 8h/day ... Never had a water-cooled system that may sit for a week or 2 (or more) between use. ..

[boarder2k7]

In the world of lasers, you definitely get what you pay for. A lot of those machines you will have to tinker with both mechanically and on the software to produce good results. It's too bad good CO2 lasers are so stinking expensive. I have exclusive access to a Universal VLS 4.60 at my job and it is a work horse out of the box (well crate, it's huge). If I had to get some system with my own money, it would be a smaller setup like a glowforge. Tons of support in a large community.

Large community that I personally wouldn't touch, I've seen plenty of complaints as well. The thing becomes a brick at their whim thanks to its cloud based software too which always sketches me out.

It also costs at least double what it should for what you're getting IMO. I'd buy a China special with a Ruida controller and use Lightburn to run it. You'll get all the same features at half the cost and know it's actually all yours.

How do you manage the cooling system for a machine you don't use every day?
I ran water-cooled tig system, but they ran 8h/day ... Never had a water-cooled system that may sit for a week or 2 (or more) between use. ..

For me, I flip the on switch when I need to use it and flip it back off when I'm done. It's working out so far anyway

[DocsMachine]

I picked up a K40 for... I think less than $500. Not cheap, but also not Glowforge numbers. Cost me a bit to ship it up, but hey, Alaska.

I eventually added an analog "power level" gauge- actually a milliamp meter- because you're supposed to keep it below... what was it, 18ma? That's basically "full power" for these little Chinese tubes. You can add more power, but all that does is shorten the lifespan- you don't get any more cutting power. And on mine, 18ma on the gauge is something like 68% on the digital readout.

I also swapped on a much better external vent fan (the factory one sucked- er, didn't suck... well, you know what I mean ) and splurged on a power lift table, which I converted to use a tiny DC gearmotor, rather than a stepper, so I didn't have to mess with stepper drivers and pulse generators and such. I have it wired to a simple winch rocker switch, and it's easy to get focus exactly right.

For cooling, I just have a 2-gallon bucket sitting behind the machine, with the pump that was included with it sunk in there, and the other hose just draped back in. The bucket has a screw-on lid, so I just cut a hole in the lid just big enough to get the pump cord through. I have a piece of blue painter's tape over the hole to minimize evaporation. In two years, I've had to top it up once. (Those of you in warmer climes might have to do that more often. )

I think all told, even with crap I bought that I didn't need, I still have less than $1,000 in ti. Maybe $1,100 at the outside.

I never even touched the original software. Instead I loaded up "K40 Whisperer" and a copy of Inkscape (both freeware.) Inkscape will turn your 2D drawing into a vector file, which Whisperer takes and can burn either raster or vector.

You can even do raster and vector in the same file- Whisperer will raster black areas, and vector red. So you can have it engrave an image, then cut it out.



Doc.

[XEMON]

Thanks a lot for the details, this helps a lot.
I may re-arange my garage in the next few months and move all my stuff/crap in the side yard (covered, and will enclose then) ... I'll make a spot dedicated for the laser then, but I probably won't have the room till ...

[XEMON]

Do you add anything to the water to not get organic growth or is the laser generating enough UV/IR to sanitize it?

[Criticalhammer]

To keep laser scatter to a minimum paint whatever you want etched in black. That way the material soaks up as much of the energy as possible. A black marker will do. Thinner the coat the better.

[boarder2k7]

Not really, it takes the same amount of power onto the object to do the same work. If you paint or mask, you're just removing power from doing the work, now you have to burn through your masking and then do the exact same work to the exposed material underneath

[Criticalhammer]

Black does not reflect any frequency. If you have a purple laser etching a yellow object then its possible to get orange laser scatter. That orange frequency is lost energy. Usually more energy lost than having to burn through a very thin layer of sharpy. If the object was black then all frequencies will absorb onto the object and theoretically none will scatter off the object.

[ChoSanJuan]

I cobbled a 2.8w diode onto one of my 3d printers. It's modular so I can swap it back to the hot end and completely enclosed into one of my printer enclosures that doesn't have open view. STAY SAFE! The great thing with my setup is that the power of the laser is controlled by the PWM controller on the fan so it's easy to get the gcode to work with 0-255 levels.

To echo Criticalhammer I use dry mark/dry erase markers on the things that I want to engrave.

[XEMON]

Your setup is one of the options I consider ... Bit I hate to tear up my hot end when the printer is dialed in ...
Are you able to "mark" anodized aluminum with the 2.8W?