Need Advice Laser Engraving Acrylic "Noob"

Hello everyone! After spending most of my day on the forum I decided to create an account and post my message
First excuse my English, this is not my native language :thanks:

My case is simple, I'm totally new with lasers and I want to engrave acrylic.
I already made some research, and what I found is that CO2 laser would be cool because whatever the material, it will absorb the laser. I bought a very cheap 500mw 808 laser which I powered with 3.3V and 5V instead of 1.8V, but I just wanted to try what it could burn, and after some researches I found that this wavelenght could only burn dark things. And if i want to burn/engrave acrylic I should go to 405 or 445. I saw that 445nm is cheaper/mw.
But is a 445 3W 9mm G-2 enough to engrave acrylic? I have to precise that the acrylic is transparent/clear.

Is a 3 elements lens better for precision (engraving) than a G-2?
I just understood that these 2 models are like the most recent right?

The reason why I don't turn on CO2 is because of the price.
I want to stay in the cheaper as I can until I have results.

I will need a TTL controller engraving, right?

There is also the question about the heat, will it really heat up that much?
Do I really need a big heatsink?
Something like that could be enough?

Based on that and the test (they made?) I should be on the right track about the 445nm laser which can engrave acrylic right? especially the laser I named before(because this is the same).

Would the 3.5W 445nm significantly better for 150$ more ?

Even 445nm 2W can engrave glass? So it should be okay?

Can you recommend me on lasers and what I should know/learn please?

Thank you very much

Hello, and welcome to LPF ! I would recommend creating a thread in the "Welcome" section. Now, first off, engraving anything clear will be incredibly hard, and second,
in the LazerBlade tests they said it could cut clear acrylic, but it rejoined directly after cut. Are you planning on making your own engraver or do you already have one that you want to modify?

One last thing, when dealing with high powered lasers ALWAYS wear goggles. Even if you're only thinking about turning it on, put some goggles on.

It does cut through, and I suppose you could make a nice cut if the conditions were just right, or you could find a way to stop them from rejoining.
It works surprisingly well on white acrylic, so are you doing something that doesn't absolutely require clear? Also, are you looking to cut or just engrave?

I'm planing to make my own machine, why?
I knew about the glasses, I need to find them too. I won't let my eyes be hurt.
Really about the acrylic I don't need to cut it, I just want to engrave it

I'm asking if you're building your own because not too many people do that . Engraving a clear surface will be insanely hard, and I don't know if it's even possible with a laser, as the light will just pass through. are you planning on using some kind of coating like in the video you posted of the laser engraving glass?

I'm not planning to use any form of coat.
But with all the examples in my first post, it should be enough to be sure I can with this laser right?
Today I engraved acrylic with a Co2 laser at 15w, and even cut it, I did it in a lab, it's not mine, I just wanted to try.

I really would like to do it with a cheaper laser/machine.

Was it clear acrylic? not surprised if it was black or something, but if it was clear it's a different story. However 15W is a LOT of power compared to 2-2.5W.

H2Oxide said:

Was it clear acrylic? not surprised if it was black or something, but if it was clear it's a different story. However 15W is a LOT of power compared to 2-2.5W.

Click to expand...

i cut and engrave clear acrylic all the time on my co2 laser cutter (i even engrave glass).

clear acrylic is opaque to co2 laser light. you might night have such success with 445/405. an interesting experiment.

But according to the lazerblade it should work, any solution to be sure it is working with this laser?

EDIT: After some mails with LazerBlade who seems to use the 3W 445nm 9mmLaser Diode +G2 Glass :
"
The laser cannot engrave clear acrylic without a coating. This is because the laser frequency used passes through clear material without interacting with it. CO2 lasers operate on a different frequency which affects clear materials.
Other customers have successfully engraved onto tinted material without a coating.
LazerBlade's result on clear acrylic.
To engrave clear materials, we apply a very thin coat of black paint.
Once the engraving is finished we remove the paint with either water or alcohol.
"

UnPlug said:

But according to the lazerblade it should work, any solution to be sure it is working with this laser?

EDIT: After some mails with LazerBlade who seems to use the 3W 445nm 9mmLaser Diode +G2 Glass :
"
The laser cannot engrave clear acrylic without a coating. This is because the laser frequency used passes through clear material without interacting with it. CO2 lasers operate on a different frequency which affects clear materials.
Other customers have successfully engraved onto tinted material without a coating.
LazerBlade's result on clear acrylic.
To engrave clear materials, we apply a very thin coat of black paint.
Once the engraving is finished we remove the paint with either water or alcohol.
"

Click to expand...

That's what I was getting at. A coating will be required to engrave a clear surface with a visible light laser. IR will act differently on a clear surface, and there are some materials that do the opposite, let IR through and not visible light. The reason you will be able to engrave clear acrylic with a CO2 laser is because they lase from 9–11 μm (1μm = 1000nm). definitely in the IR range.

You might want to experiment with some dry
erase markers. Put a little on the acrylic
and see if the diode laser will mark on
it. Otherwise, CO2 is the only real option.

Hello I would like to know which one is better to engrave/cut?
And also which lens I should use with the diode to have the best performance of burning?
Because I've read that the last diode has a larger beam which is not good for burning, but it has like 2 times the power of the 3W NDB7875, so...?

I would like to try to engrave/cut acrylic so I guess I need a lot of power for that. And I don't want to try CO2 now, but maybe you have a better idea?

Thanks for your help

Please *

UnPlug said:

Hello I would like to know which one is better to engrave/cut?

Click to expand...

I assume you mean which dry-erase marker? Just experiment with them like TLS said.

UnPlug said:

I don't want to try CO2 now

Click to expand...

CO2 really would be best for this king of thing. Maybe an IR diode? You can get those in pretty high powers fairly cheaply.

My question was about "NDB7A75 or NDB7875 for engraving/cutting?" sorry*

UnPlug said:

Hello I would like to know which one is better to engrave/cut?
And also which lens I should use with the diode to have the best performance of burning?
Because I've read that the last diode has a larger beam which is not good for burning, but it has like 2 times the power of the 3W NDB7875, so...?

I would like to try to engrave/cut acrylic so I guess I need a lot of power for that. And I don't want to try CO2 now, but maybe you have a better idea?

Thanks for your help

Please *

Click to expand...

The NDB7A75 will burn better.
For the lens, the 405-G-2 is about the
easiest to use among the lenses with high
light penetration.

Here you can see the approximate
transmission spectrum of clear acrylic.



As you can see there is a sharp decline at
around 1700nm. There are diodes in this
area of the spectrum, but they are very
very expensive and horribly inefficient.
The only type of acrylic that I have seen
cut with a laser diode is black acrylic. I
really don't think there is a cheap way to
cut clear acrylic with a laser diode using
current technology. The type of laser
diodes that might do it will cost as much
as several CO2 lasers.

Marking though should be no problem if you
can find something to color the surface
black and be removed later. That is why I
suggested dry erase marker.

Oh ok, but according to the image, the CO2 laser wouldn't work.. that's strange.