Laser Power

[apeman88]

Hi,

I have a Tormach CNC and have been thinking about fitting a laser for engraving and light cutting (cutting thin materials). Been looking around this section of the forum and it seems most industrial machines are using at least 30W co2. I don't have the room for a co2 setup and no good way to mount it on a vertical mill.

I was looking at an Infrared Laser on eBay (3.2Watt Infrared 808nm laser module /focusable/CNC - eBay (item 170587358569 end time Feb-05-11 07:13:29 PST)) and wonder what this can do. Will it engrave? Cut thin aluminum (.05" or thinner)? Are small laser modules available that does not require water cooling like co2 lasers?

I've seen tweakie.cnc's setup and although impressive... I want something simpler if such a setup exist.

Thanks in advance for any advise.

Ken

[Tweakie]

Hi Ken,

I think you would be able to pyro-engrave wood and similar products but, at 808nm, it would not cut metal. Could make a very interesting project if you decide to go ahead with it though.

Tweakie.

[apeman88]

Thanks Tweakie... do you think that 3.2W unit will engrave aluminum and steel (painted and raw)? Most of my work is on 6061 Alu.

I noticed you mentioned 808nm instead of the 3.2W. What does the 2 numbers mean to engraving/cutting ability. I thought Watt would be it but have been seeing nm and have no idea what that is.

Thanks!

Originally Posted by Tweakie Hi Ken, I think you would be able to pyro-engrave wood and similar products but, at 808nm, it would not cut metal. Could make a very interesting project if you decide to go ahead with it though. Tweakie.

[Tweakie]

Hi Ken,

The 808nm (nm = nano metres) relates to the wavelength of the emitted beam and at that wavelength you would possibly need many kilowatts of power to mark the surface of any metals without the use of a special propriety coating.
A more suitable wavelength to use for engraving and marking metals would be 1064nm (a YAG laser).
There is just so much information there that it has now become difficult to navigate but if you check out Sam's Laser FAQ Sam's Laser FAQ: Welcome Page that should explain lots.

Tweakie.

[apeman88]

Thanks Tweakie!

I more I'm looking at it... the more I'm thinking I want to build a stand along laser cutter/engraver myself! :-) I understand the mechanics (pretty much the same as any 2 or 3 axis CNC... I've been learning/researching on Co2 and think I understand how it works now. What I'm still trying to find is how is the laser power controlled via Mach or direct print (I see a few that is direct print from Corel) and also trying to find out more about direct print using printer drivers. I might become a pretty interesting project!

From what I'm reading... none of the Co2 powered laser can cut metal... Is there a laser that can do it? Nothing too thick as I can do thick stuff on my CNC... it's the thin stuff (.08" or thinner) that the CNC Mill have problems with mainly due to warping when clamped and Endmill lifting the stock.

Ken

[Tweakie]

From what I'm reading... none of the Co2 powered laser can cut metal... Is there a laser that can do it? Nothing too thick as I can do thick stuff on my CNC... it's the thin stuff (.08" or thinner) that the CNC Mill have problems with mainly due to warping when clamped and Endmill lifting the stock.

Hi Ken,

The YAG lasers will cut metal but for 0.08" Alu you would still need a power level in the Kilowatts range also a very healthy financial budget.

Basically there is no heat in a laser beam, the heat is produced within the material it connects with. For CO2 lasers almost all metals are excellent reflectors so little, if any, heat is produced and no mark is produced on the surface (without propriety coating). YAG, operating at a different wavelength, does give most metal surface molecules a bit of grief creating heat, marking and possibly causing penetration of the material.
(When the summer and warm weather, eventually comes to the UK I will post some pictures and perhaps a video of my "YAG Beer can opener" - quite spectacular to watch).

Tweakie.

[Laserman FLE]

We have successfully cut .008" stainless with our 100W very easily.

If you are trying to engrave aluminum you will definitely need a YAG unless you use Thermark as Tweakie said.

How large are the pieces you are going to be marking? I am afraid that your Torchmate system will be very crude in the resolution of the machine. Most CNC laser machines are made with very high accuracy and repeatability.

By the way are you the gentleman that called the other day to discuss this retrofit?

[apeman88]

I'm still looking into YAG and still don't quite understand it completely. No... I did not call anyone... all my research so far has been google. I have a Tormach, not a Torchmate. How accurate are the laser engravers? My Tormach will hold at least a .001".

Ken

Originally Posted by Laserman FLE We have successfully cut .008" stainless with our 100W very easily. If you are trying to engrave aluminum you will definitely need a YAG unless you use Thermark as Tweakie said. How large are the pieces you are going to be marking? I am afraid that your Torchmate system will be very crude in the resolution of the machine. Most CNC laser machines are made with very high accuracy and repeatability. By the way are you the gentleman that called the other day to discuss this retrofit?

[Laserman FLE]

Originally Posted by apeman88 I'm still looking into YAG and still don't quite understand it completely. No... I did not call anyone... all my research so far has been google. I have a Tormach, not a Torchmate. How accurate are the laser engravers? My Tormach will hold at least a .001". Ken

That will work fine.
So correct me if I am wrong but your requirements are:

* Cut aluminum no thicker then 0.08" thick
* Engrave metal, plastic, and wood

If so you will more then likely need 2 systems, to cut the aluminum you will need a very hi powered c02, fiber or yag. The other aspect of engraving will have to be done with a yag. it will be very expensive to design a yag that can cut and galvo engrave the material you require.

I would find out what you are going to be doing more of, engraving or cutting. The cutting machine will more then likely be more expensive. Then outsource the other aspect until it is cost justifiable. We have 6 YAG's in house that are capable of engraving 1/16" into aluminum with no problem, along with our xyzr motion system it can typically handle most jobs. If something larger is needed for marking a different motion system would have to be built. A machine like this is in the $70K range used. The cutting system you require will more then likely be in the hundreds.

Hope this helps. Please let me know if we can be of any further assistance.

[Crispymetal-fab]

Most lasers that can cut aluminum are going to be in the 1000w or higher and be C02 powered. Your best quality markings and ingravings will done off of YAG.(or so it seems to our shop)

Also for cutting metals, you will need a good assist gas system to help control the quality of cut. Then don't forget the very important blower/ filter system as breathing in the vaporiezed Al and other particulates is not good. Your laser cutter will need to hold at least .0005+/- to help with edge quality. Not to sure how much you would really save with a home built one with every thing that it will need.

Just an idea, if you can take the time, find some auctions of fab equipment near you and try to get in. If your lucky, you might be able to get a old small footprint laser or other cutter at a price that you will almost be happy with.

Now if you do find a way to build a laser cutter capable of prosessing .080 Al fairly cheap(old used Amada's can sometimes go for as little as $50k not including shipping, so it would have to be very below this price). Please let me know as that would be a fun build.

[apeman88]

Wow... didn't know cutting .008" alu will require so much equip/budget. Thanks for all the reply... I think I'll go back with milling alu and work on a cheaper CO2 laser user strictly for engraving plastic and painted alu.

Ken

[Crispymetal-fab]

Something else you might want to strongly concider is a build your own plasma kit. If you have gantry type router table then most of your work is done already. Most of those type systems can be converted to water jet or plasma for a ok build and price.

On one of your posts, I believe you said it will need to cut up .080". Your last post said .008". It may not seem like much of one, but the power difference needed to cut those thickness is pretty big. Our shop uses our full power(2000) with a lot of assist gas to cut .080" AL at a pretty nice speed. When we cut .010 AL we dial back the power to less than 900w with only a little assist gas and cut pretty rapidly. Its been to long since I have cut Al that thin so trying to remember the cut conditions is hard, but I don't think our resinator can generate a beam with less than 870w. So it might be possible to. buy a small used laser at the power level you would require at a price that won't make you crap your pants.

And as i said before, look for auctions around your area that might have some fab equipment. You might find what your looking for.