Built an XY-Table, Need More Firepower

[r691175002]

EDIT, Nov/2010:
This post has been receiving a modest amount of traffic from others looking to build laser cutters and unfortunately I think that it under-represents the difficulty of building a laser cutter.

While the pictures can attest to the fact that I can indeed cut fairly precise shapes out of thin paper, I consider this project a failure. This cutter used about 80mW of 404nm and could cut lined paper (very thin and cheap) at approximately 2" a minute which is essentially useless. I haven't been following recent diodes but even newer 440 lasers would have trouble with anything more than paper and would likely have problems cutting white paper of useful thickness.

I would never consider building another laser cutter with anything other than a CO2 laser (even when only cutting paper). Anything below that will always be a toy. Feel free to use a diode in your own projects but keep your expectations realistic.

If you have the technical expertise to wire up a stepper motor controller you should have no problems plugging a Chinese tube into the wall and the results will be well worth it.




Building a computer controlled laser cutter has been on my list of things to do for a while and I finally got around to it:

At the moment it is using a kenom 100mW PHR laser and is able to cut pretty well. Shown with some gears cut out of paper.

A poor quality picture of a spirograph pattern.

And the individual pieces. Most are significantly smaller than 1mm.

The cutter has some nice precision and cuts thin paper very well, but I'm looking to get some more umph from it. At the minimum I would like to be able to cut thick index card paper (~110lb) and would be happier if I could cut thin balsa wood and black plastic. The laser cutter has the advantage of being able to always maintain flawless focus and consistent and stable movement but I'm not sure what wavelength or power to get.

Size and price are both limiting factors here, a CO2 tube is out of the question since I can't easily mount it. A C-mount IR seems like a good option but I have read that they don't cut white paper very well, which is essentially the only material I will be cutting.

Blu-ray cuts white paper very well for its power output and will be easy to mount, but will cost a lot for its power.

Any suggestions? I am hoping to order a finished labby build from someone here once I figure out what I can afford. Any options need to be continuous use (Not sure how long the current PHR will last).

 

[RA_pierce]

I would recommend 2-3W IR. With the right optics, you will be able to easily cut through white paper and cardstock. Black plastic will be a breeze.
You will have to make sure the focus is set very precisely. If the beam diameter is too large, the material will ignite rather than be instantly ablated.
Nice work on the cutter by the way, I've always wanted to build something like that.

 

[Laser_Ben]

Very well done! I have some 12W fiber coupled diodes here and the appropriate focusing optics if you are looking to spice things up a bit.

 

[r691175002]

The fiber coupled IR lasers seem like they would work well with my setup. What is the feasibility of getting someone to hook one up to a TTL driver like the flexmod ( http://hacylon.case.edu/ebay/laser_diode/FlexMod01.php ) and finish up the build with heatsinking etc? I've worked with laser diodes before, but I don't trust myself enough to risk frying anything more expensive than a PHR.

A cheap c-mount IR diode in the same setup seems like a decent option as well, but I don't know if anyone does builds for c-mounts. I think a 3W from herruursciences ( http://laserpointerforums.com/f55/red-808nm-1-5-watt-laser-diodes-more-cheap-39834.html ) and appropriate optics would be ideal, but if a fiber unit already comes with the optics mounted it might be worth avoiding the hassle of a c-mount

12W is a fair deal more power than I need, but out of interest how much would that kind of setup cost? Feel free to PM me if you prefer.

Finally, when one gets into the 5W+ range are glasses still enough or does one need better eye protection? Is this level of power high enough that if you were to catch the dot in your peripheral vision (with glasses on) you could receive permanent eye damage?

Thanks

 

[Flaminpyro]

A 12 watt actully would not be too much power as you would not run it at max power ! this will make the diode last a lot longer than if you buy a 2 watt and run it at max all the time.
The other thing is you realy can use a co2 set up as you would not mount the tube so it moved with the head insted only the final optics move and the beam is conveayed to them through mirrors from the base where the tube is, maby I should take a picture of my 10 watt co2 machine and put it up here for you that would be easer than me trying to describe it all, be right back...
here is the company who made this model.

turn it on.

With the top open you can see the carrage in the back.

so this is the working end it moves in both X and Y planes it takes in the laser light on the left and shoots it stright down, the part that says 1.5 on it

If you look at the far end on the back you can see an aperture , there is a yellow warning sticker next to it.

The co2 laser energy comes out of that yellow window and enteres the black box which moves with the carrage, there is a mirror that turns the beam to the right and sends it to the other moving mirror which turns it down to do the cutting.

The tube and power supply has been switched out with a 10 watt model.

Pyro..

The fiber coupled IR lasers seem like they would work well with my setup. What is the feasibility of getting someone to hook one up to a TTL driver like the flexmod ( http://hacylon.case.edu/ebay/laser_diode/FlexMod01.php ) and finish up the build with heatsinking etc? I've worked with laser diodes before, but I don't trust myself enough to risk frying anything more expensive than a PHR.

A cheap c-mount IR diode in the same setup seems like a decent option as well, but I don't know if anyone does builds for c-mounts. I think a 3W from herruursciences ( http://laserpointerforums.com/f55/red-808nm-1-5-watt-laser-diodes-more-cheap-39834.html ) and appropriate optics would be ideal, but if a fiber unit already comes with the optics mounted it might be worth avoiding the hassle of a c-mount

12W is a fair deal more power than I need, but out of interest how much would that kind of setup cost? Feel free to PM me if you prefer.

Finally, when one gets into the 5W+ range are glasses still enough or does one need better eye protection? Is this level of power high enough that if you were to catch the dot in your peripheral vision (with glasses on) you could receive permanent eye damage?

Thanks

 

[mmykle]

You can't ask around for how to correctly equip a laser to your CNC machine without a tutorial on how to make one! Haha. Seriously though, how did you go about making that? I saw a youtube video on how to make one a long time ago but it wasn't the best tutorial ever. I'd love to know where you learned how to make yours.

My suggestion though, would be to use a new 12x blu-ray diode. They can output ~420mW if I recall correctly. 2-3W IR lasers would work pretty well too I imagine, but like you said, paper doesn't absorb it as well as UV light. Seems like you have some money though (enough to make a CNC machine anyways), so buy both, and see which one works better for your needs. :yh:

 

[r691175002]

Building a laser cutter is actually pretty simple. Because the laser doesn't apply any force to the machine you don't need to worry about rigidity. All you need is a pair of motors and some threaded rod.

My machine looks sharp but I used an arduino instead of a real stepper motor controller so the axes are limited to about 11" per minute. This machine was only ever intended for paper and crafts.

My original intention was to get a few hundred mW of blu-ray since it would be easy to hook up, but the more I learn about some of the IR diodes the better they look. I could likely get 12W of fiber coupled IR for less than a 12x BR. And the IR wouldn't be running over spec. My only question now is how would one power something like that? With 12W of power TTL modulation is a necessity but I'm not aware of who makes drivers for anything bigger than pointers.

CO2 is awfully tempting as well, but I'm not sure if I have the space or alignment precision to set up mirrors like that. That's an awesome machine, and I'm hoping to get something similar once I grow out of this guy.

 

[mmykle]

Yea your on your own for IR stuff... I have no experience with that. You could try contacting whoever you buy the IR laser from. You would think they must know how to properly power it.

I was going to get an arduino for xmas! But requested more laser stuff instead... damn. Although I could just buy one I guess. If I had access to stepper motors (which I do), would I need an arduino? If so, what code are you running on it? IE: how do you load an image on your computer, then have the CNC "print" it? I would really really love to make one of these, and seeing has how its second semester senior year for me (High School, not college) I'm sure I'll have plenty of time on my hands.

 

[r691175002]

To be honest, an arduino is a really bad way of making a laser cutter. I just did it because I didn't want to fiddle around with CAD programs and buy specific CNC hardware (that stuff gets expensive).

There is code online that takes vector images and chunks them into a series of steps (like left left up right...) and I just send those one at a time from my computer to the arduino. I needed to write all the code and the workflow is a little clumsy but it works fine. Like this I can just draw some squiggles in inkscape and cut them out, instead of trying to learn autocad.

The biggest disadvantage of using an arduino and h-bridges like I did is the motors turn very slow. A real driver will use extremely high voltage and then limit the current so that the coils don't burn. I am controlling the motors using the motor shield ( Motor Shield - Arduino motor/stepper/servo control ) which is really just a toy.

That being said, it works just fine for what I want to do and let me get by with cheap hobbyist level stuff I had laying around. You could build a cheaper controller by wiring some ICs to a parallel port but you loose convenience and parallel ports are a pain to find these days.

 

[Kenom]

Wow, now that is inventive use of a Kryton barrel. (as ,mario said in laserchat "+1 Kenom ego")

I've got a 2W IR in one of mine as well as lots of folks have got 8x bluray diodes in them at 400-500mw. Using the existing setup would work wonders if you upgraded the Kryton. I'm not sure IR would be your best choice for a laser for this. I've tried a 9W-20W and not had much success with quick burning on white paper.

 

[jaycey]

Thats a great build you got there, would love to see it cutting some balsa. Could inspire me to have a go at this!

Thanks

 

[r691175002]

Although I expect bluray to cut white paper better than IR I am hesitant to use an overdriven harvested diode for continous use.

For example, I expect the PHR I am using to die in the near future just because it is spending several hours on at a time at many times its rated power. I'm pretty sure its power is dropping but it is still running for now.

 

[mmykle]

Although I expect bluray to cut white paper better than IR I am hesitant to use an overdriven harvested diode for continous use.

For example, I expect the PHR I am using to die in the near future just because it is spending several hours on at a time at many times its rated power. I'm pretty sure its power is dropping but it is still running for now.

Actually PHR's are known to be quite stable if properly heatsinked (which yours seems to be). What mA's do you have it running at? If I recall correctly, someone on the forum had it running for like a month to see how long it would last but it wouldn't die. Maybe Kenom knows more about it.

 

[cpsim]

That is a nice build for the xy table. working on a similar project. and is that the adruino board for your controler?

 

[gagasignor]

Hi all,

so obviously I'm not the only one trying to build a diy laser cutter ...

my project has reached "milestone 1" so far: a diy plotter build from 2 old scanners, controlled with an arduino mega clone AND selfmade processing program to import SVG files and send them via USB to the plotter.

but now comes the second part - the laser. and I'm quite impressed, how complex this seems to be. after some research I think, I understand how the driver works and how to switch the laser on and off.
but, as asked in many posts in this and other forums, the question of power and wavelength of the laser remains open. and as laser modules in the needed category are not that cheap (especially when you have to buy protection goggles for the respective wavelength also), I don't want to buy something that doesn't work.
unfortunately the information given in internet forums regarding thie topic varies widely from "take a diode from an old dvd-burner" to "nothing under 12W". also the relationship between wavelength and material to be cutted remains unclear.
in my case I want to cut index card paper like r691175002 (the initial poster).

Has anyone some hints and information for me? will some 250mW BlueRay Diode do the Job?

Thanks!
Christian

 

[scriptster]

You've got enough firepower to have some fun already!

I'm just curious as to why everyone is so fixated on cutting paper with a laser? Paper cuts very well with blade cutters and those (even PC-controlled as of more recently) are cheap and plentiful.

I'm using a CNC laser cutter for a different material that I consider much more fun than paper (although that's obviously a personal preference) - craft foam. It's perfectly suited for laser cutting due to foam's very low heat transfer rate that promotes evaporation instead of flaming up. Additionally, it cuts terribly with a blade due to high friction, so IMHO it's a perfect material to learn your laser cutting skills on. Well, yes it's a toy (unless you're a painter and cut yourself foam stencils to use for business) but it's cheap, very forgiving and a great fun.

Oh, and 2-3mm craft foam cuts well (though not all colors) with a simple and cheap red 200mW diode.

Below are some samples (the CNC files and SVG sources are here)


So, anyways, the point is: don't just drop the project because (white) paper doesn't cut well with a laser - there are so many other uses for it and you can also make it an educational project because it touches on so many subjects - from physics to machining and CNC.

Cheers!