[sharpen047]

Hey guys ive been looking at adding a laser to my current CNC, its a 5'x6' CNC i built myself mainly for wood/aluminum. I made it out of 8020, i currently have a router running on it and its pretty good but id like to have a laser cutter and or engraver on there too. I cant find any solid state lasers that arent made in china and over 20w unless i spend 25k on a full cnc. I was told by another member to try to stay away from tubes because they can leak and go out in a month or two, so i am trying to go solid state.
Does anyone have any recommendations on what brand to look at for a laser system?
I see rofin has some cutters and some engravers, can a more powerful laser not do both if turned down?
My main use of the laser will be cutting acrylic/polycarbonate for computer cases and other misc things.
im trying to stay in the sub 600$ range but if i need more ill end up saving for a decent, long lasting laser.
Any help would be appreciated.
Thanks!

[Exsecratio]

decent Solid state under $600 isn't going to happen sadly.

Even a powerful glass tube will cost more than that

Glass tubes have a minimum strike level of 8 to 15% power, engraving with 15% of 150 watts is still going to cut right through 3mm acrylic hence the reason the rule of thumb is dont go above 80 watts (CO2 glass) if you want to cut and engrave.

best wishes

Dave

[wontpontificate]

In addition to the power limitations of solid state lasers, and the cost, you run into a few other problems that make them impractical compared to gas tube lasers.

First and foremost, you'll run into physics. Diode lasers have a much shorter wavelength than CO2's 106µm (most are FAR shorter than that). CO2's wavelength is so far into the IR spectrum that for the purposes of cutting and engraving, it acts more like a "heat beam" than a light beam, and thus most substances that are transparent to visible light are opaque to CO2's wavelength, so instead of passing through them, it'll cut/engrave them.

The opacity of most things to CO2 lasers also makes them easier to safety shield, since an ordinary sheet of transparent plexi will generally contain any stray eye-boiling reflections. As you get into shorter wavelengths, you have to look into special filtering and more specific goggles to keep your peepers safe.

CO2 lasers are much more amiable to rapid switching on and off. Diodes like to be soft started, and rapid blinking of a high powered diode can (if you're using a driver not designed with this in mind) shorten the life of your (expensive) diode. Heatsinking is also a concern as you increase diode output, since them diodes like to run cool, and burn themselves up if they get too hot.

I don't know what your router looks like, but I have seen some successful designs with the laser tube and flying mirror assembly mounted to the top of the moving gantry. I'd be hesitant if you did want to add CO2, to mount the tube at one end or the other, without some sort of containment to make sure you don't accidentially interrupt the beam with yourself by leaning in between the mirrors.

What materials were you looking to cut or engrave, and what would your cutting/engraving workflow be? are you planning on doing all vector stuff, or doing scanned raster cuts too?

-C

[sharpen047]

My router is a dewalt 611. Frame is 1"x3" heavy duty 8020 with 3/8" thick rail bolted to it. I have room for the laser behind the y axis and room to bolt a plate on it if needed.so i have both slots of the 8020 open and clear of the railing.
I dont know anything about what lasers and lenses are needed with a gas tube laser, and wouldnt mind learning a bit in the process. I designed it all myself and it will be very easy to make whatever changes i need to get a laser on it.
I mainly plan on cutting out plexiglass and woods like pine and oak, id like to engrave both also. If i need to run at slow speeds i can. i currently have no workflow because i JUST built the bigger cnc(had a 20x18" cnc for working out bugs) and my g540 bit the dust and is out for repair.
i am guessing a scanned raster cut is going back and forth like a printer? thats what would be hard on a high power diode type laser?
Mainly vectors bud id like to "do it all" if i need to. if i go with a 40 or 60w laser i could engrave by turning down the power to the laser and cut by turning the power up?
i also dont know what electronics are involved for controlling a laser either.My router has adjustable speed, the g540 outputs pwm but i would need another power supply right?
Thanks for the help. Really appreciate it!

[Exsecratio]

but i would need another power supply right?

Very much so, laser glass tube run between 17Kv and 35Kv (although very low amps) still bloody hurts if things go wrong though (imagine attaching yourself to a defibrillator)

thats what would be hard on a high power diode type laser?

It would likely kill the diode very quickly even DPSS systems don't like to be mucked about with and heat is a huge problem for any diode based system

i also dont know what electronics are involved for controlling a laser either

about $500 worth of cards and controllers, plus the mirrors, mounts, tubes,psu,lens's etc.

Before looking in to it though, thick woods (read over 10mm) DON'T cut well with a laser at all, they char and burn especially hardwoods like oak. Unless you get into kilowatt systems lasers aren't really all they first appear to be. While the laws of physics place no limitation on the power that can be transmitted by a laser beam there are a LOT of practical restrictions (the biggest one being cost) (in theory a death star type laser IS possible, if we had 1,000,000 times the number of power stations the world currently has)

If your not fully happy with lasers, as C rightly says above, avoid short wavelength stuff, 405nm etc, they blind in fractions of a second if an accident occurs. Stay with 1064 (far IR) such as glass tubes etc as you can protect yourself at sensible cost. At least strays will get sucked up by the mirror / metal sheet in the rack / glass on the table etc and won't go bouncing round like a psychopathic lightsaber

best wishes

Dave

[sharpen047]

http://www.youtube.com/watch?v=GhTrR...ature=youtu.be
What kind of laser is that?
i see people engraving only with .7w lasers, while slow, are these more affordable?
do all lasers over a watt or so need eye protection? even the far into the IR range ones?

[Things]

That is a YAG laser, very expensive and designed to run at very fast pulse rates. Not what you want on a (relatively) slow moving gantry.

To be honest, a CO2 tube is going to be the way to go here. High powered diode lasers are expensive, fragile, require very complex driver circuitry, need to be kept at a constant temperature, and have huge beam profiles that are very difficult to focus to a small point, and will have a MUCH larger kerf than a typical CO2 laser. It also will not touch clear materials like glass or plastic.


And yes, I'd highly recommend eye protection for even 1W of visible-near IR lasers. CO2 lasers are different, as their wavelength is around 10600nm, most of the light is adsorbed in the outer layers of the eye, whereas visible and near-mid IR will be adsorbed deeper in the eye.

0.7W/700mW isn't going to cut or engrave much of anything. Might be able to slowly cut through some <2mm black plastic, but it'll take all day and leave more of a melted edge than a clean cut.

[Hurricane21]

Sharpen,

Please consider Hurricane Lasers for your purchase. We have a full line up of lasers for consideration. We are based in Las Vegas and stock all of the parts etc here. All of your support will be here and English speaking. I think you will find we have great support and service as well as pricing. We integrate our machines with US Parts such as Meller Optics for the lenses and mirrors. This gives our customers a combination of great price with quality components where they are needed. All of our lasers come with a full 2 year warranty that overs everything including the tube. And we actually honor our warranty.

Please check us out at http://hurricanelasers.com/products/lasers

Thank you and best wishes.

John

[wontpontificate]

Here's your basic CO2 laser flying mirror assembly (disclaimer, no affiliation, just something I found on a quick ebay search. There're more options out here, this'll just give you the basic idea)

http://www.ebay.com/itm/A-set-of-CO2...item35c449e9eb

You'd mount the tube atop the gantry and then install the mirrors to bounce it around in a u-turn, in line with the motion of your "laser nozzle" mounted to your router carriage. that'd bounce it down toward your cutting bed, and do some work for you.

I'd stick with a 40w tube, myself. With a rig like this, you probably won't need any more, and bigger tubes get more unweildy, and you'll have fragile glass tube sticking off the end of your gaitry just waiting to get bashed off by someone or something in the way.

Additionally, I'd mount the final "laser nozzle stage" at a fixed Z on the gantry, so that there's no chance of accidental misalignment, and burning a hole in your wall/self/cat/etc. Control your lasering Z by choosing a distance from the nozzle to focus to, and using riser blocks to get your workpiece to that height.

You'll be limited in your cutting ability unless you connect air assist, and for that, the nozzle needs to be fairly close to the workpiece. It helps keep the smoke out of the beam, as well as clearing out your kerf as you cut. Even if you're too far away for air assist, I suggest optics that support the use of it, and keeping a small air pump going, just to keep positive airflow through the nozzle. It'll help keep the smoke away from your lenses, keeping them from getting fouled up.

I drew a (terrible) top-down sketch of a router gantry, with a really rudimentary positioning/mounting guide so you can visualize what the heck I'm talking about:



There are CO2 laser PSUs out there that do TTL control, so you can wire up Mach or EMC or whatever it is you're using for machine control to turn it off and on. A popular choice for laser power control in g-code is M03/M04, so you can use the spindle enable pins. It'll make your life much easier. You'll want to mount the laser PSU on your gantry if you can, to minimize the length of high voltage cable you're dealing with, and for the sake of safety overall (that's how I'd do it anyway) -- you'll want to make sure that you test and modify your accelleration/decelleration settings in Mach/EMC to compensate for the extra weight, and also to try and give your tube a more gentle ride. Too much shaking isn't good for it, and can also jar the mirrors out of alignment.

Most cheap CO2 tubes are water cooled, so you'll need to think about running water hoses as well.

Overall, it's not the easiest thing in the world, but it's best bang for your buck over diode lasers, and you'll be a lot more satisfied with the results.

Plus, having a big glowy glass tube on top of your gantry will make it look -MUCH- cooler. Mad science effect for sure!

-C

[wontpontificate]

Oh! Just found this: http://www.flickr.com/photos/stevehobley/8210357484/

Guy who built a dedicated cutter with his tube on the gantry instead of fixed, but some inspiration for sure!

-C

[Klausgogo]

Hi Sharpen..!

I am standing in exactly the same situation as you .. I would like to laser cut acrylic and other stuff.
I am considering buying a laser cutter! But it will probably cost me 2500-5000 usd. ..
.. But i already have a "flat bed router", so I´m thinking about mounting a laser on my router.

I have also considered diode laser, but probably come to the same conclusion, as recommended in this thread. To go for a CO2 laser.!

My router is a German produced http://www.cnc-concept.de/Basic1500, which should be useful for this purpose .. !

So, for me this it is a very interesting thread you have started here, as I have many of the same questions ..

Klaus Lund
Denmark

[mikefalkner]

I want to thank "Things" and "Exsecratio" for their comments and knowledge. I too was thinking about adding a 100w diode laser to my large 6' x 10' DIY CNC router machine. But after reading "Things" and "Exsecratio" comments, I will be adding a CO2 system to me gentry. However, since I have a tall Z-column, will add the 40w CO2 tube directly to the Z-column and save myself some mirror alignment issues, and some safety concerns. One pf these days, I'll post from photos if I ever get it done, ha.

Again, thanks to "Things" and "Exsecratio".

Mike

[GWKlaser]

To sharpeno47

we have a mini model of laser machine. Storm500 1500USD.
working video.
https://www.youtube.com/watch?v=zI8QSw1QwA8

Maybe you can donsider this one.

[Nolan Yang]

here is a video for difference between servo system and stepper system,hope it can help you learn about laser cutting and engraving machine,thank you!(chair)

http://www.thunderlaser.com/video/de...er-system.html