CNC enclosures

[owhite]

Hey people,

This is kind of by way of introducing myself, I'm making a relatively large cnc table which will be used in conjunction with a 100 watt CO2 laser for cutting sheet metal.

Okay, this will be the fourth cnc table I've built, but I've never gone to something this size. It has to be around 8 x 6 feet.

The laser will release undesireable fumes when its cutting acrylic and galvanized metal so it needs to be relatively airtight. There'll be ventilation to be certain.

sooOoooo, I'm looking for suggestions on different enclosures. Right now its looking in my mind like a room within a room, probably 6 feet high 10 feet wide, 6 feet deep, made mostly from 2x4 and plywood, with a pizza oven-like door with plexglas windows. Sounds clumsy and inelegant to me.

what thoughts people? feel free to be creative.

Owen

[ToyMaker]

You might not need to completely enclose your machine. The chemical and electronics industries use exhaust hoods in their "nasty fumes" departments. They partition 3 sides of the work station and the hood sits on top. The air flow captures 100% of the noxious stuff.
Then there is the question of how to filter the captured air. You probably can't just vent to the outside (osha, epa, other regs?).
I don't have a link handy but Altavista or google will no doubt turn up hours of reading material.

robotic regards,

Tom

[owhite]

point taken. I guess I was thinking of enclosing it because I've seen a number of pictures on sites where they completely enclose the lasers. maybe to reduce problems with sparks. when you cut metals it basically produces a flame that looks like a mini-cutting torch.

o

[bcromwell]

There is more to CO2 Lasing than just fumes to worry about, Don't forget about reflection, you don't want to take someones eye out... Even though Co2 lasers can't pass through the corina to get to the retina they can (will) do serious burns on the outside of the corina which is almost as bad...

[owhite]

Yes.

My optics chain is completely enclosed until the beam leaves the cutting head and hits the part. That leaves an open gap of less than 0.06 inch. Reflection off the part is still a possibilty at that point if it were to hit something other than a flat surface.

Because of a their long wavelengths CO2 beams reflect off of anything. I was running some tests with a 25 watt and used a traditional beam stop which was a brick. The beam reflected off and scorched my chest. My first attempt at home tattoo removal.

But your point is a good one and probably accounts for why many (certainly not all) CO2 cnc systems are enclosed. Curiously, I've seen some in the 1-2kW range that are simply big flat open beds.

My enclosure will use either glass or plexi both of which do a good job of blocking the beam.

Just to keep the thread on topic -- still looking for suggestions on various enclosures -- verbal and pictorial suggestions welcome.

Owen

[ToyMaker]

Good point about eye protection. I saw (with both eyes, thank you) a sign in an optics lab that read:
CAUTION
Do not observe operating laser with remaining eye!

Grim humor, but I still chuckle

robotic regards,

Tom

[Hobbiest]

A full plexi enclosure that someone could walk inside of would be really expensive! Somethign that they would do on Monster House would be a pexi enclosure that drops down from the cieling and that would be so cool! Bit impractical though! I'd build it like a small workshop, with an industrial sized exhaust fan at the top to vent to gasses to the outside. That way you could just put an inspection window in it...better yet, one small one on each side...and you don't pay through the nose for plexi.

[owhite]

I agree, there's no chance I'd make the whole enclosure out of plexi. I'm thinking of mostly 2x4s and plywood box with a front cabinet door with horizontal hinging a lot like a pizza oven -- the plexi would simply be a window on that door.

If I was operating on a bigger budget using plexi I'd go with the aluminum extruded framework with internal plexi panels.

This gives an idea.... of what I dont want to do, that is.

Owen

[balsaman]

I would make a room with a man door and the pizza door. Interlock the man door with the laser shutter so you can walk in safely to do adjustments etc.

E-man

[pack rat]

I kinda have a problem with 2x4,plywood in presence of a cutting torch. What about metal studs and metal siding?

[Hobbiest]

Thats a great choice...cheap, easy to install, light too. But this is a CO2 laser right? No flame right?

[pack rat]

it is the word association thing. "yea I use state of the art laser to cut metal panels with 6000F temperature inside the large wooden crate". I think that is the reason why he brought the question up in the first place. Another tought. There are panels use in porch covering made out of fiberglass and also of metal, with sealant foam for edges. Maybe make rooftop that you can remove easily to gain acess from the top.