advise options needed on laser upgrade/add on

[george uk]

Hi

I know nothing about lasers and CNC so am looking for some general opinions as am looking at can i install one on an existing matching. I will list the bit that i need to have an understanding about

1. What extras do i need on any controller for a laser ( currently thinking of cs-labs cp- )

am currently trying to decide on the controller for the full machine......what do i need to be considering...what problems ?

2. Mounting positions and angles.

This is the real thinker. The machine i have, will allow me if its better, to mount the laser tube, onto an air assisted Z, vertically ( not needing as many reflectors ) and use the beem directly out of the tube. Any problems or opinions on this ?... Also, this will meen the tube is moving a lot... will this cause problems..... How much do i need to sheild the tube...

3. Can anyone give me a general run down on,

laser power vs distance vs cutting power
anything i need to know about accuracy.

I think we will be using the laser for etching pics on stone and metals etc, hopefully quite detailed ones, but am thinking if its done correctly, we may also be able to use it for cutting when required. Am hoping, that because i can use it straight out of the zube, and can accurately get the distance on the Z, i could possibly use for both.

There are probably questions i should be asking, but dont understand i should yet ( think donald rumsfeld, unknown unknowns )

I DONT KNOW ANYTHING ABOUT LASER SETUP SO FEEL FREE TO ADD ANY OPINIONS / ADVISE

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[george uk]

any suggestions of a place i can find the answers or have a good read up on the above.

[Robin Hewitt]

any suggestions of a place i can find the answers or have a good read up on the above.

If you want UK laser chat with laser freaks who actually do this stuff, how about http://oplaser.co.uk/opsupport/

[Robin Hewitt]

Here are some basic answers to get you started. You do not want to move the tube. CO2 laser tubes are large, fragile glass things and require inconvenient things like 25kV and water chiller pumps. Even the small 50W tubes are about 70cm long so this is kind of bulky. Engraving involves scanning the head in the fastest moving axis whicht wants to be really zippy. You bounce the beam around off gold plated mirrors then focus it at the last moment. Focussing is usually one lens because columnating a thin beam would be a bit harsh on the last one, this means your beam comes to a focus somewhere inside the thing you want to cut and diverges either side so there is a kerf if you go thick. All sorts of sublimates pour off the target and you really don't want them condensing on your optics or soaking up light that should be doing the cutting, so some kind of down draught is a very good idea.

[george uk]

Thanks for that.

Am mainly thinking about etching into stone, am at the planning stage so i can change were or how its going to be mounted, but i do have a large area on my Y/Z arm, plenty of hight and saftey. and if its easyer, the machine is 4500mm long, so i can anex one end.
12808 So if its possible adn feasible and makes sence, mounting a tube vertically or horizontally on the z is not a problem, neither would cooling.

My machine quoted max speeds are
Maximum Speed of X Axis: 2,165 IPM
Maximum Speed of Y Axis: 1,770 IPM
Vectoral Speed X-Y Axes: 2,796 IPM
Maximum Speed of Z Axis: 710 IPM

Would that be to slow ?

Am thinking, if i can mount it direct on the Y/Z i could change tube and powerpack and focuser if i needed i higher power cut, like steel, but i dont understand if it will cause the laser tube any trouble by moving so fast.

So, if that is nbot doable, i was thinking of another problem, if i have to fix the tube on the Y or X, and a solution.

Beam strength over distance.

If the tube is fixed, do you get variation in the beem strength, and does the software/hardware deal with this. I was thinking.
Could i mount 2 fixed 40w tubes at each end of my Y and combine the beems at Z, therefore, giving level power down the full length of the Y.

As you can tell, i really know fa about lasers, but a lasers a must for what am planning, Iether for etching stone or cutting metals. Am adding a a few more items like scanning heads, probes, but i need to finalise the plan for the laser, as everything will have to fit around that and its wireing.

after looking, am wandering if i could use a laser diod as well for etching

[Web Goblin]

The laser assembly could be mounted on the machine without any problems. This takes away the need for long flight tubes, beam paths and alignment issues.
What materials and thicknesses are you thinking of cutting? For steel at anything above thin sheet material you will need alot of power.

[GEOFFREY]

I don't know much about lasers (have had a 900x600 60W machine for about 3 years now and have never managed to set it up!!!), but if converting a commercial cnc router I would have thought it best to use a fixed head, moving XY table machine so that the Z axis is only used for the focal length. G.

[Robin Hewitt]

etching stone or cutting metals

I have heard rumours of people managing to cut steel paste mask stencils with 120 Watts but the surface had to be dulled down first. I have no idea about engraving stone. When I think "laser cutting metal", visions of enormous 2kW machines with oxygen assist spring to mind. Can you find someone who has done whatever it is you are trying to achieve and see what they are using?

[george uk]

Hi

after reading up last night, i will just concentrate on etching stone/othere items with a laser. I think i can achieve what cutting steel with a plasma torch add on easier.

I want to be able to etch pictures on stone like these 2
https://www.youtube.com/watch?v=i-HgWC7eurw
https://www.youtube.com/watch?v=GLDH5U_zY9A

am open to changing any design plans if required, i am trying to avoid having a different machine to laser engrave, and i can also add a Y mech just for the laser if i need to.

I also see this and though wow,
http://www.mycncuk.com/threads/7237-Combined-CNC-Engraving-Technologies-Spindle-Laser

and if diodes are good enough, i could use one of them instead. Like i say, i know FA about lasers so all opinions / ideas welcome. I want to end up being able to etch on as large a bit of stone as possible, i may purchase a smaller laser machine for smaller placks ( or if anyones selling )

In relation to cutting steel.( with whatevers required )

I was thinking that it may be a good side idea to supply pre cut and drilled/milled steal frame components for people wanting to build CNCs, Allowing them to bolt it together prior to wielding it. and marking out fixing points for them. Am fairely sure i can supply these cheep enough, with bolts, to make it economical for home builders wanting to do solid machines over 1mtr.

Any advise on being able to achieve the above would be welcome.

[george uk]

Found ths usfull, for a basic understanding of beem power/focus/distance

http://www.parallax-tech.com/faq.htm

will update when i work out were am placing the tube.