Large dust collection system. 3D parts. crossflow?

[odulfst]

I machine alot of 3D parts out of foam, and it makes a hell of a mess and people don't like being in the shop with dust that will have some unknown effect on them. Right now I follow the bit with a shop vac, and that kinda works ok with some foam. The skirt I have works great with flat parts, but gets in the way of the 3D stuff. My idea is to have a large volume vacuum/pump set up to flow accross the table in the y axis and that will span the x distance of the table. This will keep a steady flow of air going over the table and hopefully be able to catch most of the dust. I would also probably attach an air nozzle pointed at the bit to keep the cutting surfaces clean of debris. Has anyone seen a setup like this? Is there a vacuum that can support that kind of flow? we have this big portable dust free painting room....I guess I might be able to adapt that.

Thanks for the advice in advance,
Tony

[paco]

Hey Tony!

I use the air nozzle when cutting foams to keep the chips/debris from covering the machine and it's rails/rollers. I thought about the vacuum setup you suggested but haven't made it yet; I just vacuum the floor (X end) with the shop vac and I'm happy so far but I do not cut foam every day so...

The air nozzle work great and I have found many other use for it and plan on to control it with an output. Just need to find time to finish the relay control board project! I use the Locline hose system and a control flow valve with a gage. You don't need much air to keep the bit and working area clean.

[frank_hav]

Tony

I also do alot of 3D work. While I have not done it yet my thought it to enclose the machine in a wood and plexiglass room. Then just vacuum the whole room. Even a small vacuum should create some negative flow as long as the room is fairly tight. It also would keep the dust in the room even if it did not get it all the first time.

My other thought is to make the machine table a down draft table.

Frank

[odulfst]

Thanks for the ideas guys. I'm going to have to do something like this, so don't hold back any suggestions. I'm happy to be a guiney pig.

Paco, is that an electronically activated control valve? that would be very interesting.

Frank, I like the down draft idea, and we're still considering enclosing the room. Only thing is it will have to have big doors for getting the occasional large piece of material in there. I recently had to cut a 6' wooden circle for a microphone array, so it had to hang about 3' out of of one side.

keep the ideas commin.
Tony

[Towersonline]

I recently visited a ShopBot user, they cut large blocks of syntatic foam. Their solution to the dust was to enclose the Bot in a plastic/ canvas garage 12x18ft. This in addition the the vac system helped considerably. The product is made by Cover-It and several other manufacturers.

Bill Thorpe

[gerald_d]

Tony, you don't need big doors - just a large postbox slot. Have a look at the link for some ideas:

http://www.mechmate.com/Forum/messages/53/53.html

[odulfst]

Gerald, Thanks for the link. We were leaning towards something like that, but once in a while we will need to machine some really odd shaped stuff. maybe a really big postbox slot. maybe i can just put a wall on hinges.

I have plenty of room and funding, so I'm trying to be as creative as possible. Though that cover-it thing looks real simple and easy.


i'm thinking now that a large enclosed room with a vacuum system that sucks down around the edges of the table (between the table and the steel) but i'm not sure if that would make it too hard to clamp things down. I could get a vacuum hold down system as well i suppose. hmmm.

[paco]

Yes Tony, I plan to control an electro valve with a controlled relay from one of the SB3 output signal. Soon, everything will be controlled via output signal; vacuum, dust collector, air jet and I have some more idea as well. Having the air jet controlled via output signal can save some workload on the compressor by switching on and off the air on jogs which I can have plenty of when cutting out shapes...

I have tried the downdraft system without success. Right at the tool bit blow I prefer...

[dingwall]

Similar to the Cover-It, I used to have shower curtains surrounding my pin-router with a dust collector hose at the bottom. It got pretty dusty in the work area, but kept the rest of the shop cleaner.

I liked the shower curtains because they were easy to move out of the way and didn't restrict too much light.

[normand]

look (air curtain ) like frozenfood display.might have to redirect router air to the vacum

[jf_allie]

How about flat transparent bellows attached on either sides of the X and Y car to contain the chips. Then maybe at the end of the cutting, use Paco's air hose to robot sweep the chips towards a vacuming gutter either at the sides or at one end of the table.

Is there space for a bracket that would provide attachement surface for the bellow while clearing the Y car motor?

Questions:
Where would the bellows go when cars reach extremitites ?

Would a piece of folded polypropelene be sturdy enought to span the width of the table?

The folded sheet of polypropylene could be strong on a hight tensioned steal wire (curtain style) running along the edges, but is there space to clear this wire.

More simply, maybe the polypropelene is v notched to sit and glide on the rails. This way it could be easily removed when in the way.

[odulfst]

wow, i like the idea of being able to write a "clean-up" program. I've spent alot of time thinking about how to install some kind of easily removable and somewhat compact walls.

most recent idea in my head now is hinged plexiglass (or wood/plexi) on the open ends, and either permanent or sliding plexi on the long sides hanging on the c-channels. my thought is to make enclosed walls around the edge of the table with about 3 inches clearance all around. Hook up a big vac under the table (maybe with a "drip tray" type design) and just leave the top open (or put a dome on it w/ a vent if it lets dust out). I think the downward flow of air will keep dust from going up and out. then an air nozzle at the bit wil keep the chips away, and i could still writhe the super cool clean-up program.

did anyone actually understand that?

[gerald_d]

A down-draught table will just move the dust to another place (the exhaust of the fan) where the problem might even be bigger. We had complaints from the bakery next-door because our roof exhaust was near their ventilation inlet....

[patricktoomey]

Mmmmmm, MDF Biscuits, yummy!

[bill.young]

I used to buy big bags of very fine sawdust as filler for epoxy. The bags were labeled "Wood Flour" and had a Pillsbury label on them. I finally asked the sales guy why Pillsbury sold sawdust and he said that they sold it to bakeries for making high fiber bread!

[patricktoomey]

Based on the amount of sawdust I eat everyday I guess I've been on a high fiber diet without knowing it! Unfortunately it's mostly plywood dust so I'm probably on a high formaldahyde diet too. I'm sure it's all controlled as far as species of wood and such. If they mixed the wrong species of tree in there it could be very interesting. I breathed/ate quite a bit of padauk dust during a project a few years back. It smelled really sweet and didn't bother me until later that night when I got violently ill and broke out in a rash. Whoops! So now I wear a respirator while working with exotics.

And now back to the topic...
I have an upcoming job which will involve cutting about 200 board feet of padauk and wenge on the bot. I'm going to build a temporary booth around the machine and evacuate the dust out through my shop wall so I don't poison everyone in the shop, just the neighbors :-) I really like Sheldon's idea of shower curtains. I'm figuring on using my explosion proof spray booth fan which moves an insane amount of air to do the sucking and then run through a multistage filter so I don't flood my neighborhood with pretty red snow from the padauk. I figure my regular dust collector will pull 90% of the dirt, the curtain booth will contain the rest and will force all the cleanup dust when we blow off finished parts out of the shop. The big fan should keep the booth seriously depresurized so nothing can blow back into the shop. Sounds good in theory anyhow.

[odulfst]

lol. maybe i can bag and sell saw-dust. that would really raise profit/materal levels too. haha.

Gerald, I was planning on buying a big dust collection vacuum system to do the sucking. are there any that would move enough air? I can't really vent outside, the bulding is really a big wind tunnel with work space around and underneath. hey, maybe I can use the BIG fans to do the dust collection, lol. 4MW/H might put me a little over budget though. There are a couple retired small scale tunnels around though....maybe i can adapt one of thoughs and just run it through a collection system.