Conversion of CNC router to Laser... what do I need?

[llema]

Hi everyone. First time here. Looks like a nice forum!

Anyway, I have a CNC router (gantry style) in which I would like to replace the router with a laser head. The machine cutting range is 60x24x12 inches. I've been trying to get a good grasp on the information I've managed to find so far, but still am very uncertain of what is actually required to do this kind of conversion. The materials I cut are mainly plywood from 1/32" to 1/4" in thickness. I also cut solid wood up to 1" thick. On occasion I cut aluminum plate about .100" thick.

My main target however is to be able to cut the plywood with the laser. If I can do the solid wood also that would be a plus.

Can anyone give me a sort of parts list of components I would need to make this conversion. Or even better, a price on a bundled package containing all the necessary components?

Thanks in advance for your help!

Marc.

[Tech_Marco]

You will need a 60W or bigger laser tube to handle wood cutting. To avoid the dark burning issue, you may need to inject Nitrogen gas to the air nozzle.

If you're familiar with G-Code and Mach3 and mainly for cutting, then you can do it easy with my 3-axis stepping motor driver board. But as you know, Mach3 isn't good for PWM and it's not good to do engraving.

By the way, CO2 laser can't handle metal cutting, not even 0.1mm. Well, it's not true if you can get a 200W or 400W CO2 laser with pure oxygen to assist. It can cut metal then. But dealing with pure oxygen is dangerous and extra caution required.

[llema]

I already have the CNC, all stepper motors, drivers power supply and Mach3... the machine is already working. I just want to take out the router head and replace it with a laser head. So with a 60w head I could cut plywood up to 1/4" thick and solid wood up to 1"?

Is there a kit available that includes a laser and all support equipment ready to be mounted to the flying head of the CNC machine? It looks like I you need mirrors, lenses, supports, tubes, power supply, etc... a all in one head that would mount in the place of the router motor would be awesome...

BTW, I'm not really concerned about the wood showing burn marks.

What would be used to set the power to the laser to adjust for different thicknesses of wood to be cut?

[Tech_Marco]

Not a good idea to use CO2 to cut for such thickness. Remember, there is a focus point issue as the light beam coming out the lens isn't straight/parallel. It's like a trangle shape with wider top and narrow down to a point and that point is where we call focus point. As beam go beyond the focus point, the light will divrse out and power getting weaker. If you're not looking for a fine line cutting and accept the tolerance, then it's ok. For 1in board, I think you should go for the 80W or 100W for good sake.

[baccus61]

I have a 100 watt laser and I can cut through about 20mm or 3/4" of wood but very slowly . MUCH smoke is made when cutting so you need to vent the smoke out as much as possible and also there is a residue left by the cutting that gets over everything and is time consuming to clean off. Creosote I think from the wood sap. I don't do it as much as I would like to for that reason.
I always recommend a 60 watt laser for someone first starting out as it's a good price/performance level of a laser. I started out with a 30 watt and after a year found it so limiting that I wanted to upgrade to a 100 watt as soon as possible.
The 100 watt glass tube I have can engrave on paper or cut through wood so it is pretty versatile. The power range is from 4% up to 95%. I VERY RARELY go over 90% of the power as the laser tube will last a whole lot longer if you don't and if I need that much power to cut something then I obviously need a higher wattage tube to be able to do it, so I don't.

I would recommend just copying what others have made. Laser tube along the back and top left for the 0,0. home position.
3 mirrors and 1 lens assembly.
60 watt laser tube and power supply. (if you really need to cut 1" of wood then go up to a 150 watt tube. They are BIG so you will need the room to put it. About 6 feet long )

If you can find some photocopier mirrors then they will do at a pinch. I used them on my 30 watt laser and the aluminium surface is a lot more resistant to scratching than the gold ones. If you get gold mirrors then DON"T clean them like the Chinese people show you. You wet a piece of lens paper and put it on the mirror and slowly drag it off without putting any pressure on it at all. Just the surface tension of the alcohol is enough. If you rub the mirror with a Q-tip then you WILL scratch the gold surface and slowly reduce the mirror effectiveness. Isopropyl Alcohol is the stuff to get. Any Chemist store will have it but they might charge an arm and a leg for it so shop around.
I use a lens blower brush to just clean off the dust that builds up and only clean with lens cleaner if I absolutely have to.

You need to keep the glass tube cool and if you live in a hot environment then a water chiller will be the only thing to use as it's a PITA to keep swapping bottles of water out from the fridge inside when the temp gets to 30deg C.

Use only distilled water or de-ionized and put a couple of drops of photographic wetting agent in to reduce the bubbles that get trapped inside the tube.

The DSP is the only way to go as it's cheap and VERY good at what it does. Don't look at my set up though as I am having problems with it that I have had for a very long time and not necessarily due to the DSP from Lightobject.com. Everyone else is having a ball with theirs.

All the stuff you need is found here on Marcos site and is probably the cheapest new stuff you will find out there. He also backs up his product unlike a lot of other sellers that run after you buy something. This is why I give back in return as much as I can here on his site. Other Chinese people would do well to mimic him.

Just remember to keep your area clean and you won't have too much trouble. My laser is stuck out in the shed with dust and crap all over it but as long as the lens and mirrors are clean then there isn't a problem.

If you want to see what we have to put up with where I live then look up " Broken Hill dust storm " on YouTube and you will see what I mean. We had 23 of them last year due to the 10 year drought. Now we have wide spread flooding.....just can't win.

Also remember to NOT clean the output coupler on the laser tube with anything other than Alcohol as there is some AR (anti reflecting) coating on them that will be harmed if you do. Use the drag method outline above. Try to keep it shielded from dust as you want to clean it as little as possible. Never is better! I glued the red diode pointer housing to the cover of mine so it is shielded from the atmosphere and all the crap in it by the beam combiner lens so I shouldn't have any problems. I read somewhere that a guy has used just a ZnSe window and it reflects enough of the red pointer to be useful so you don't need a $120 combiner lens, juts a $40 window. You would have to try it yourself I suppose.
READ as much as you can on lasers and go to the http://www.cnczone.com and check out all the stuff there on them as well. (you probably already have)
Mach3 is good for cutting but the DSP is WAY more versatile and relatively cheap. Mad if you don't get one, I think.

Let us know how you go.

All up cost will be around $2000 but that's just a guess.

Buy from Marco and you WILL get after sales service from every one here.

Be well.
Rich.