MPCNC with LASER!!!!

I have all the parts ordered (cross my fingers) this is my third V1Engineering build having done a MPCNC and a Low Rider but I’m planning on making a MPCNC solely for a laser (https://jtechphotonics.com/?product=3-8w-laser-and-2-5amp-safety-compliant-driver-kit) So I have the basics of building the machine down just curious on the Laser aspect. Just wondering what people that use lasers on here use for their machines and what programs do yall use for your g-code and to run the machine. I’m hoping to be able to cut thin wood and even engrave pictures with it. Though on this one I did cheat because when I went to start 3D printing my parts my Prusa printer decided to go completely crazy so I went ahead and ordered the 3D parts.

Look into air blasts to clear smoke while cutting. It’s pretty easy to do, a flex tube and an aquarium bubble pump. Getting the smoke out of the way of the laser beam makes a huge difference in cut quality and speed.

Sorry, but I’d like to hijack this thread and see if anyone has input for what kind of safety eyewear they use for the most commonly used wavelength, 445-450 nm blue/violet laser?

Is Eagle Pair from Survival Laser about the best cheap set? Or are they not enough? Do the cheap cheap green pairs work?

How can we focus a laser (aside from setting it at power level 1) safely? I don’t need to watch it run.

I’d like to put together a guide on using the laser, which I don’t think has been done aside from informally in forum posts (unless it actually is in Leo’s guide, which I haven’t read past the building instructions).

Thank you.

They are enough for me using a 3.5W diode laser. OD5 should be good for looking directly at the spot of a 100W laser. (Not directly at the beam, just the spot on the work surface)

Never had a pair. Did have some cheap red ones that came with a 2.5W laser and I really didn’t trust them.

Start with low level to get it close, and then Ryan has posted a script that burns full power, moving the Z axis every line. Take note of your original starting distance from the work and then add the distance indicated by which burnt line in the script is the finest.

You do need to be present, with a fire extinguisher handy.

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I definitely 2nd that!

I took his statement to mean he didn’t feel the need to look at the beam to find a good focus if there was a better way to focus the beam. But if it was meant in the sense of walking away from the machine while laser cutting, DON’T!

Now besides when your looking at the laser to focuses it and set up would you need to put a protective barrier (for example weld curtain) to be able to safely run the laser while doing other things near the laser that you wouldn’t want to have to ware the googles for?

[quote=65351]
Jeffeb3 wrote:
You do need to be present, with a fire extinguisher handy.
[quote=65357]
Mike wrote:
I took his statement to mean he didn’t feel the need to look at the beam to find a good focus if there was a better way to focus the beam.

Of course I would not completely walk away from the machine. Mike, you’re mostly right in just wanting to be able to focus the beam, though having some safety while nearby would be very applicable.

The confusing thing I’m finding now is that the laser has two parts which we should not look at: the beam and the spot. With the beam pointing downward at the spot, and the two being connected, is there something I’m missing here? How else are we supposed to look near the spot if the beam is directly above it? It seems like there is less to worry about in our use cases (versus a physics lab performing laser work) because the laser is pointing downward and has very little z-distance from the work piece, therefore the beam is very short. I also thought that, unless the air is very humid, or has particulates (such as smoke, fog, or dust), that the beam is relatively invisible. Is this the reasoning behind the beam warning, as in “don’t look at the beam - it is invisible, but it is there, so avoid it.”

The way some people talk about it makes it sound like “don’t even look perpendicularly at the beam.” That is our use case.

For safety of persons nearby, I have seen a couple of methods of protection. Enclosure of the entire machine with either mostly solid walls and a window made of this. Or other products like it. Or an entire enclosure of welding curtain like this. I don’t know how much I would trust the curtain though. It isn’t specifically rated for laser use. The other option is to build a small enclosure or plate around the head of the laser with the laser protective plexi (see the additional photos on the jtech page).

When we say don’t look at the beam, we mean shoot the beam directly at your eye through the glasses (or heaven forbid without glasses!) Same as don’t look down the barrel of a gun.

The other situation where your eye could be exposed to a significant dose of beam radiation would be through a specular reflection, such as off a mirror, or other shiny object in the work area, bolt head, etc. The glasses would protect you in this case, but best not to do it on purpose.

Edit: I remembered I had seen someone use the welding curtain as a test with lasers somewhere. Found it here. So I wouldn’t use the curtain as a primary means of protection, but seems like it would work pretty well as a general barrier for safety of passers-by.

I tried Miller welding glasses and they worked great, I was able to observe the arc on the stick welder our contractors were using without any pain, or headaches. They are very comfortable and are easier to put on and take off than normal shade 5 goggles.