Optically compressed laser module?

Hi!

I saw this product today :

(I hope you can see it in your own language)
It’s a small laser cutting / engraving machine, low cost (around 300$), equipped with a 5.5W CO2 laser. But it claims that the effective power is equivalent to a 90W laser, due to a (so-called) optically compressed laser module.

The seller claims that it can cut 15mm thick wood, which I can hardly reach with my 100W machine…

So… what do you think about this? Is there some kind of lens combination to better focus the laser, or shape the beam for higher energy density? Or some voodoo laser thing…?

Many of us are skeptics…

Take a look at this thread where @genepaton claims to have successfully tested the 15m claim.

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Thanks Don, I see I’m not the first one to wonder about it.
It would be interesting to have more feedback from him, though.

Here is the “technical” information given on Aliexpress:

  • Laser Effect Power: 90W (cutting effect compared to 90W CO2 laser)
  • Electrical power of the Machine: 30W (this has nothing to do with the cutting or engraving performance, just the electricity consumes)
  • Diode laser power: 5.5-6W (please note that this is light energy, not electrical energy)
  • Laser wavelength 455 ± 5nm
  • Engraving accuracy: 0.01mm

They say the laser beam width is 0.06mm (or 0.08mm in the video): how does it compare to standard CO2 laser cutting machines?

One difference I can sse is the wavelength : 455nm makes it a blue laser.
CO2 laser are usually infrared around 10 000 nm

Does anyone know if wood absorbs blue radiation?

I found a test here (in French, sorry):

But they don’t speak about the cutting performances.

Also a test on Youtuber, in spanish:

And an interesting test here:

It doesn’t seem so interesting after all…

Yes, blue lasers are used quite commonly for wood. There are many years of experience of hobbyists using DVD blue lasers for engraving wood, and of course a dedicated designed module is more effective.

It does make sense that a more narrowly focused beam would be more effective.

It will not however cut clear acrylic!

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I think it’s important to be clear here, you do not have a CO2 laser.

You have a Diode laser, it has a much smaller beam with the similar intensity per square mm as the CO2 laser. And it has different capabilities and attributes.

I have a similar unit (claims 40W with a 0.08mm spot) and it does many wonderful things, it engraves wood, etches mirror backings, cuts paper, cuts plastic foils and engraves multi layer plastic signs. It also cuts thin wood and ply, and I have made nice things with it.

But…

  1. If your primary goal is to cut thick plywood you will be badly disappointed. The tightly focussed nature of the beam works against you, it just doesn’t pack the same punch as a fatter beam with a full 90w of power behind it, it cant quickly punch all the way through the piece in one go.
    Instead you need multiple passes, you need to lower the beam focus between passes and add some sort of air-assist. This will always be much slower than a CO2 laser, ok for hobby work but if time=money you will be rapidly wanting the ‘real thing’.

  2. It can be very fussy about what plywood it will cut, I have some 5mm ply that cuts like a champ, and some 3mm that takes twice as long and never comes out perfect. The glue used makes a huge difference, some is translucent to blue light and effectively kills the beam at that layer. And if you hit a flaw in the inner layers where the gap is being filled by glue then that bit will never cut and, depending on it’s size and location, might not be fixable with a craft-knife.

  3. Blue light changes the range of materials you can cut. Many materials like wood, paper, etc behave the same. But others such as transparent acrylic and many metals will only absorb the infra-red laser wavelengths, the blue laser does not affect them because they reflect or transmit it away. This can work the other way, eg blue lasers cut copper better than IR. But overall it is a disadvantage, not a benefit.

Dont feel cheated if the above seems negative, you still have a very good tool at a very sharp price. It’s just that the advertising on Ali-express etc generally makes a traditional snake-oil salesman look like a saint.

It will need some practice and time to learn how to use it properly, but I only got my machine last summer and here is a selection of wood+paper things that it has cut, and there is more I’m not showing.


(‘40W’ diode laser with my home-made air assist)

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That looks like the MangoJelly elephant?

Lol, that took a bit of googling… turns out elephants like mango.

It’s very similar but not the same, came as a drive-by download from 3axis.co (warning, ad-bombs) when I was gathering some DXF’s to test LW with.

It has horrible import scaling problems, but is such a nice model that I’ve actually made half a dozen now, at various sizes scaled by wood thickness, makes a good simple gift.

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Didn’t mean to send you off googling! For anyone else I confused, “MangoJelly” has been creating youtube tutorials on FreeCAD, and relatively recently did one in which he showed how to create a design like this. I had no idea that elephant pen holders were a thing more generally. I guess I don’t get out enough! :stuck_out_tongue:

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No need to apologise, it was a fun google, better than most of the stuff out there in the babblesphere,

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dang, I should have scrolled down before I started my search for what “Mango Jelly elephant” was. LOL

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