Newbie cnc diode laser question

Like Giarc mentioned, I use my Diode laser to engrave items that are vary greatly in thickness, from a few mm to several cm. The laser has a specific focal length, and therefore distance, it needs to be from the work surface. So I modified my ACRO (which has an adjustable Z, but manual, by loosening some bolts and manually repositioning) with a powered Z axis to more easily focus the laser. I 3D printed a sort of cone, that snaps on to my laser, which allows me to quickly and easily zero my X, Y, and Z axis for the workpiece. And while I don't cut with mine, cutting with a diode does usually require multiple passes, and you should be readjusting (lowering) the focal point of the laser with each pass.

 

My diode has a screw-barrel focus on the lens itself. I use Z pretty much entirely to micro-adjust focus and dial in material thickness.

 

Yep

JTech Photonics sells laser shielding. Don't cheap out and buy orange acrylic, not the same thing.

 

Personally I'm building it in as an enclosure window so the beam is fully enclosed. If you have a fixed focal point that can't be adjusted with a screw barrel, then building a surround is certainly an option. I'd probably use that instead of glasses whilst working generally around the shop, but if I was at the machine I'd have the glasses on as well. I've seen that recommended in a lot of places, it may even be OSHA guidelines too, it's been a while since I looked at those. Shielding is generally intended to prevent stray reflections rather than protect the user looking directly at the dot, I think. Certainly the safest way of treating it.

 

You make sure you build extraction into the case..

 

There are various approaches to ventilation. I went fairly simple for my ACRO / Diode laser build. I've got a couple of large volume fans in the back, which pushes the smoke / fumes through flexible ventilation hose attached, which vent to the outside.

 

Ah... I think some of us were confused as to what you were asking. I had when you were talking about an enclosure, you meant the entire machine. You're talking about just the laser head itself.

I don't have the Jtech, but I would not think that surround goes all the way down to the work surface. There's going to be some space there. And that fan most likely isn't puttling air out, it's pushing it in. You want some positive air pressure going down around where the laser is hitting the work surface.... this is going to blow away the smoke, dust, etc from the working area, as well as to put out any flames that could pop up on you. You would then need a larger ventilation fan that will then clear out the smoke and fumes to the outside world.

 

Right... the smoke can dust can foul up the laser lens. You wan that air to blow that stuff out of the way, so it doesn't ling around the lens and foul it up.

I'd also be leery about having a permanent attachment that goes all the way down to the work surface, even if not fully enclosed. All it will take is for your material to have a slight raised spot, then that's going to catch and either break off or move the workpiece and destroy your work.

 

I don't have a better picture right off, but if you look at the attached picture, you can see what I did. If I need to adjust my z height, there's a plastic cone I snap on to my laser. It actually comes down to a small point...I think 1mm. So I can use it to no only line up my x and y, but adjust z as well. Then, once I've got those set, I pull the "cone" off.

 

I've got the entire assembly in an enclosure. (See the above pics I posted...) There are two doors on top missing from the pics. Long run, I'd like to have some laser shielding / acrylic windows in those lids. But that stuff is expensive. I wear goggles when I'm first starting up a job, with the lids open. But once it's running, I close the lids. I've got a camera (a Wyze v2 Camera) inside the enclosure that I use can use to monitor things from my phone. I throw the goggles back on any time I'm going to open up the lids.

 

Yep!