Hello everyone!
By the topic you can guess how noob I am.
I am portuguese and my english is far from perfect, so sorry in advance. (Any misunderstood is google translator fault )
So, i’ve tried to clarify my doubt on the internet but I haven’t found anything that clarifies me properly. I resort to your help hoping this is not already a debated subject (at least I didn’t find anything enlightening on the forum)
I’m working with Lightburn and a diode laser GRBL generic machine.
I’ve been experimenting a lot with different materials (as ideas come up). Right now I’m trying to engrave clear acrylic and from what I’ve read UV technology would be the most suitable for what I want.
Knowing some of the risks of diode laser machines due to the emission of UV rays, I had a doubt whether a diode laser is the same thing as a UV laser.
All uv relates to is the frequency of the laser beam…
If the laser is in the visible spectrum of frequencies then anything that is clear will not be able to damage (cut or engrave) that material…
You can generate most of the frequencies with a solid state (ss) device or led.
Some of the modules for these machines are available that operate in the uv spectrum…
I understand they work for acrylic but I don’t have one of those, mine are led, co2 and fiber… they have a different to no effect, depending on the material.
Was any of this useful?
Lots of people use these without problems. I know of no one who will look into the laser beam…
It’s only going to emit uv if the laser is designed to emit uv. So I think you’ll be safe with either…
Hi Jack, thanks for the quick response.
If I understand correctly, summarizing the technology (if that’s what it can be called) a generic laser diode (in my case 40W) is not considered UV because, quite simply speaking, you can see the beam of light and from what I saw in a video of a UV laser the ash is invisible, only the engraving is visible.
If I understood correctly, then from what you mention and the image below, only diodes that work at a frequency below 400nm are considered UV, right?
There are plenty of diode lasers that run in the UV range…
Anything that damages material will produce some type of debris… the laser doesn’t destroy things out of existence. Could be gas if it vaporizes the material or any size of debris depending on how the laser damages the material…
My fiber can push a wad of metal debris along in front of the beam…
If it’s not in the visible range you can’t see it… that’s a lot of bandwidth of frequencies that can be used… There are a few…
Tanks Jack.
For now I am clear about the doubt that originated this topic. Of course now I’m more curious about UV lasers but that will be a subject for debate later.
What you can do is mask the clear acrylic with something like tape or paint. My guess is that when the laser burns the mask, it will melt the acrylic underneath and make it seem engraved. I have a 450nm 7watt diode laser and have done this with glass achiving pretty good results.
EDIT: Just tried with blue painters tape on an old CD case. I know I have some real acrylic around, but I just moved and cannot find it.
I was wondering: my laser has 455 nm wavelength too. It is beyond UV, of course, in the blue range: that’s the visible color when it works.
Isn’t blue tape (or anything blue) inefficient?
My understanding of physics (which might be wrong) is that blue material is blue because it strongly reflects this color. Isn’t something red or orange, or just plain black, more efficient for such masking?
You are correct. If we were sipping amps in some mission-critical application, or using a much lower power laser, efficiency might be a concern. At this level, unless its white tape, I don’t think it’s factor worth worrying about.
Hello Tim, thank you for your reply.
That’s an option I’ve been thinking about. My concern is if it left any residues of tape on acrylic. That´s not suitable for what I intend to do.
Meanwhile,…
Some material test i have made with acrylic. Power from 10 to 100%, speed from 500 to 2000mm/min, 40W diode laser 450nm and air assist.
Spayed with black acrylic paint on one side.
First test i try to remove the paint with thinner. (I am convinced that I already clean acrylic with thinner but,… maybe not. )
Second test I used acetone much better result but far from ideal.
Third test, as i do not have any solvent at my disposal I try to invert the acrylic sample and and run a material test. Until here all tests were made with painted surface face up, this test was made with painted surface face down.
I run a test like this because I intend to evaluate the reflection effect on acrylic.
The result was interesting,… cracks everywhere, down side (painted side) melted on the most power and lower speeds hits, and curios is at 100% power between 2000 and 1500mm/min it burns face up side.
It does leave some residue on the plastic, but was easily removed with a product called “Goo Gone”. I’m sure it is sold under different names, also called citrus cleaner, or something like that. The cleaner does not harm the plastic at all.
Hi Tim,
I think that is “stick remover” and yes it possible to buy here in Portugal. Which by the way is a good country to born if you want to talk Portuguese.
Thanks for your reply.
I have to open a new topic for this matter because it looks “off topic”. My doubt about UV Laser is answered.
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