What to use for a laser cutter

[Azzabcd]

Hello,

first of all, sorry if I'm not doing it right, this is my first attempt to this forum...

I've been reading various posts on this forum for the past few days and now I know a lot more about laser but I still have a few interrogations.

I'd like to build a laser cutter with those 2 minimum requirements:
- cut white cardstock
- use to create PCB (etch black paint...)
- ...

I already have some of the materials: 2 old scanner, stepper motors with controller, Arduino, old computer (power supply, cd-rom...) and I'm planning to build a power controller using a LM317, but when I come to which diode to use ??? I'm stuck!!!

I know that CO2 laser would do the trick, but if possible, I'd like to start with something smaller... and less expansive.

Reading the posts gave me a few lead (M140 with G2 Lens...) but before to order something an being disappointed, I'm asking help from people who already went thru this kind of project.

Based on what I've read, the eye protection to use depend on the type of laser, so I'm waiting for your suggestions before to buy them.

So please if you have any experience in this type of project, I'll be more then happy to receive your suggestions (model, type, link to previous post I may have miss...). I will also greatly appreciate any of your experience (good or bad).

Thanks

 

[Azzabcd]

OK, now I see I'm not in the right forum...

I was expecting to have an option to select the right forum, my mistake.

Any way to move it to the appropriate one or do I have to write a new thread?

Thanks

 

[TimTom]

Maybe you got the wrong section

 

[Aleksa]

I'm not sure what power will suit your application,but you will need at least 300mW. I would use a 1W 808nm diode. Infra Red light is dangerous,so be careful.

 

[xirrious]

Infrared is dangerous because you can't see it. 1w for all practical purposes is 1w regardless of wavelength. I made post explaining why different wavelengths burn differently but the difference is negligible nd I believe 808nm are less expensive then other diodes of equal power. Don't quote me on that though I could be wrong. Safety goggles ALWAYS with infrared because as previously stated it's invisible thus you have no direct reference to the beam vector.

 

[Aleksa]

Different materials absorb different wavelength. You cant easily cut white paper with lets say 650nm. You will need a lot of power to achieve fast cutting. While the CO2 laser(1090nm) can cut white paper like its nothing.

 

[xirrious]

Above post is kind of obvious but good info none the less. Darker materials will burn quicker. The diode suggested to you is best for cutting white material as we all know white materials tend to reflect all wavelengths nearly equally. Infrared is exempt from the is general rule of thumb though as its outside the visible spectrum that creates white in the first place.

 

[hakzaw1]

PM coming about affordable cutter no matter what color

 

[upaa27]

Different materials absorb different wavelength. You cant easily cut white paper with lets say 650nm. You will need a lot of power to achieve fast cutting. While the CO2 laser(1090nm) can cut white paper like its nothing.

Co2 doesn't emit at 1090nm bud. Did you mean to say 10900nm as that would be more accurate. Standard emission of co2 is at 10800nm so pretty much nothing has that wl. Therefore, nothing can really reflect it.

Rest of the info is solid

 

[xirrious]

That's not exactly how it works. The smaller the wavelength th e better that it'll cut. High wavelength actually means it burns LESS effectively per watt overall then a smaller wavelength photon which has less uncertainty in its wave potential field and a more precise quantum position. This is what is truly responsible for how well light and photons burn materials.

 

[upaa27]

That's not exactly how it works. The smaller the wavelength th e better that it'll cut. High wavelength actually means it burns LESS effectively per watt overall then a smaller wavelength photon which has less uncertainty in its wave potential field and a more precise quantum position. This is what is truly responsible for how well light and photons burn materials.

I was not referring to power but to absorption rates. A 445nm 10w will do nothin to a piece of glass whereas 10600 will be absorbed almost completely.

 

[xirrious]

Ya I understand materials behave differently under light, that's more chemistry through which I don't have great knowledge in. Sorry bud, hope my info was useful anyhow though not an answer

 

[swamidog]

I was not referring to power but to absorption rates. A 445nm 10w will do nothin to a piece of glass whereas 10600 will be absorbed almost completely.

well.. i have broken very expensive glass lenses trying to build a collimator for a 15W 445 module i built a while ago.


wavelength is a factor, as is energy density.

 

[upaa27]

well.. i have broken very expensive glass lenses trying to build a collimator for a 15W 445 module i built a while ago.


wavelength is a factor, as is energy density.

Wow! That is very interesting. I have never seen nor heard of that before.

What kind of lenses were they? Did the have a coating? Reflective loss?

 

[swamidog]

Wow! That is very interesting. I have never seen nor heard of that before.

What kind of lenses were they? Did the have a coating? Reflective loss?

they were AR coated for argon (501-457nm). we were moving the secondary lens into place and it got too near the beam waist and shattered.

as you can see, it's scary amount of energy:

 

[upaa27]

Really nice!

Maybe the lens was really wl selective or at least enough to shatter it.

The stuff you make never ceases to impress.

+rep when I can