Newbie- Diode lasers - what can they do?

[Pairair]

Hello all!
I´m building a small router, approx. 500x500 mm. It was, or is still, intended for engraving (with a rotating tool) and pcb milling.
However, while browsing eBay, I found a small laser diode, 635nm and 300mW with a driver, and I bought that. I was thrilled to see what that tiny little thing could do. It will cut 3mm depron (the kind of material that model airplane builders use) like butter, and do some engraving on wood. And yes, I have the proper eye protection.

So, I'm kind of hooked on this laser thing. Let's say I get a 20W or 40W diode laser, maybe fiber coupled, what would I be able to engrave/cut? With the proper collimating/focusing lense that is.
How do different wavelength effect characteristics of the laser?

Any thoughts welcome,

Per

[zax15uk]

Per,

You are in a similar situation to where I was 18 months ago. I also added a 250mW (being driven to ~300mW) 635nm diode to my CNC and used it for some light engraving and XPS foam cutting. The speed wasn't that fast though.

The higher power diodes are most likely 808nm (low IR) so potentially much more dangerous, can be expensive for power supply and optics too.

The fiber coupled lasers if correctly focused (not easy or cheap) would be capable of cutting thin plastics/wood and light marking on some metals (gold works ok). Not very practical but it depends on your application.

A much better option would be a sealed CO2 laser (10,600nm / 10.6um), the tube and PSU would be mounted to the rear of the machine and a couple of special mirrors used to reflect the beam to the cutting head and focus lens. You can buy the components and add to your machine or get a small Chinese system and have both (what I chose to do).

Wavelength has everything to do with the capabilities of a laser.

What materials would you like to cut/engrave?

Zax.

[Pairair]

Than you Zax.
I would LIKE to be able to cut 1/2 inch aluminum... but seriously maybe 1/8 plywood. And it would be great to engrave anodized aluminum. I do some anodizing myself.

Per

[zax15uk]

Engraving on anodized aluminum isn't too difficult, the higher powered laser diodes or cheap 40W CO2 tube would do that (with excellent results).

Cutting 1/8" ply is a little more difficult, the epoxy resins can be a problem especially exterior grade materials. CO2 would be the ideal solution but you should go with an 80W+ tube and air assist to achieve a good cut quality.

It may require 2-pass cutting with Z-axis focus adjustment between cuts.

Zax.

[Cromaglious]

I'm looking building a 4' x 9' vacuum table with a XYZ gantry for cutting fabric - Cotton, Cotton/Polyester, wool, acylic, leather, nylon. I'm trying to figure out what would be the best laser to use for cutting cloth would be. Trying to work on the cheap. A 60ipm cut rate would be fine.

Thanxs for the help!

[zax15uk]

CO2 wins, power requirement would depend on thickness. 60W would be fine for most typical fabric thicknesses.

Cotton and Cotton/Poly cut ok, Wool I haven't tried, Nylon melts and doesn't cut very well (may be ok depending on application) and Leather is just stinky (thin cuts ok though).

Zax.

Originally Posted by Cromaglious I'm looking building a 4' x 9' vacuum table with a XYZ gantry for cutting fabric - Cotton, Cotton/Polyester, wool, acylic, leather, nylon. I'm trying to figure out what would be the best laser to use for cutting cloth would be. Trying to work on the cheap. A 60ipm cut rate would be fine. Thanxs for the help!

[knutselsmurf]

I've been searching the net for the same thing, but came to the conclusion that diode-lasers are beeing used for welding and soldering, not for cutting.
This seems to be becouse of the build of the diode;
An array of smaller diodes are joined together in a multi-fiber cable.
Though they are packed together tightly, is doesn't have the beam quality of a laser tube.
Focussing this beam (okay, it's not actually a beam) to a spot will give a bigger spot than the tube will do.
Therefore it is able to heat and burn, but not cutting trough things.
Of course you can focus to a smaller spot with a smaller focus-distance, but then you loose the ability to cut deep.
So, to me it sound like a no-go for cutting.
I think engraving would be okay, when you use smaller focus distance.
If any of this is not correct, please let me know.

[Cromaglious]

Originally Posted by zax15uk CO2 wins, power requirement would depend on thickness. 60W would be fine for most typical fabric thicknesses. Cotton and Cotton/Poly cut ok, Wool I haven't tried, Nylon melts and doesn't cut very well (may be ok depending on application) and Leather is just stinky (thin cuts ok though). Zax.

I figured as much on the leather -- Though looking at the Actiontec leather cutting system... leather looks to be pretty cuttable using a knife. I think Nylon would also be knife cuttable. So it looks like I'll have to do a knife + laser + pen/ink jet z axis. knife is looking like an addition axis for knife rotation. I'm almost thinking about doing some sort of plunge cutter setup - which would be slower than molassas, not to mention noisy. I could use a harbor freight pin nailer to drive the 1/8" round cutter with air solenoids to fire the cutter and an exhaust the waste from the cutter. I'd have to run an exhaust hose from the cutter hammer to catch any oil. Have to some kind of non-staining washable oil.

Hmmm thinking.... I'll have to play around with fabbing up a cutter. May have to try a router spinning a cutting bit with a collar on it to allow the blowing out of waste in the bit. This would be slower than a impact cut, though probably more sure to cut the material.

This week I'm working out at a winery so it'll be next weekend before I can really play around with this.

[zax15uk]

Yes, you can cut leather very effectively using a knife plotter.

It is best with a tangental blade (rotary theta axis) but a simple drag knife works ok providing the design isn't too complex.

Rotary cutting is an option to consider but for thin materials a knife or laser would be much better.

Zax.