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water bed is fine to cut thin plates, it maintains the plate cold and get no warps. also keep the dust inside the tank.
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Hi Guys,
I am just about start building a CNC Table for my plasma and am finalising the design.
Now I see a lot of people out there with water beds under their tables and have seen a couple with extraction fans and a hoper system.
Just wondering what is better ? I see the water could keep the work cooler as it cuts but the extraction fan system could be cleaner.
Any comments ?
water bed is fine to cut thin plates, it maintains the plate cold and get no warps. also keep the dust inside the tank.
This question comes up a couple of times a week. A little reading of old posts will uncover a wealth of info.
I use a water table after testing out other schemes that didn't work well. You can test out a water table by fitting a pan of water under some steel and give it a go then make the same cut without the pan of water...
What is a hoper system?
John
yes I used the search but like a lot of things people like to comment all around and I couldn't really find anyone who was using a suction system.
A hoper was what I was planning on building under the table with teh ducts hooked up to it so when you turn it on you get even suction over the entire table. I have an extraction unit large enough to ensure all dust etc goie into the filter.
I see your point about the water cooling tha material as valid and something else to consider.
I was just thinking that water would be pretty messy compared to a ducted extraction system.
this took about 5 seconds of scanning the topic titles...
Air exaust system help needed.
John
Yep and I read it. It doesn't make a lot of sens though cause if you have water 10 - 12 inches below the slats it will have no effect on the temp of the sheet at all and from th einfo there they are saying it just catches slag. Once again not making a lot of sense to me.Originally Posted by Big John T
If the wat isn't goingt to cool the sheet as you cut then why not just catch the crap in the hoper and get rid of the water all togeather..
Anyone got any pics of a down draft ??
Cheers and thanks for your help so far
I'm guessing you read something from somewhere else as I can not find any thing in that link about the water cooling the sheet...
You need to try a hopper first... then it will make sense.
John
Yep it is not in the post.
2nd post in this thread says " water bed is fine to cut thin plates, it maintains the plate cold and get no warps. also keep the dust inside the tank." whih is where I got the water keeping the sheet cool from.
Then in the post you posted a link to they suggest " I agree with Tom....if you can design the system with water approx 6 to 12 inches below the top of the slats.....and pull a downdraft with your blower from above the water...then you will have a good system. Depending on what you are cutting....as much as 60% of the particles will be captured by the water....which makes taking care of the remaining 40% or so much easier."
Which would then suggest that the water is not touching the sheet is a better way to go so that the down draft system can pull the dust pre water and allow the water to catch the solid material.
From what I have read I see most people use water as it is simple and provides a reasonable amount of effect. Most of these seem to have the water lapping at the sheet whilst it is being cut.
By having the water touching the sheet I can see cooling benifits. I can accept the down draft system will be a little more complicated to setup but if it provides a better solution then that is fine.
Does anyone out there actually run a downdraft system ? If so any pictures / comments ?
I have had a down draft table for a couple of years now and can say it takes out about 90 % of the dust.
Keep in mind all the stuff you suck out from under the plate has to go some where! I just blow it outside.... Not ideal depending on where you are.
I use a 24" dia. paddle type fan turning about 700 rpm, pulls a lot of air out and is fairly quiet.
That being said I have not tried a water table......
I cant imagine cleaning out that mess!
I have two trays under the table that I can pull out with the forklift and dump into the scrap bin, simple and easy.
Also a catch all for all those little parts that fall through the grate!
They can be a real pain!
Good luck, Steve
I bought a air handler ( down draft ) unit with my table, it works ok for the most part, the duct work and exhaust fan are nothing special, just a old furnace fan and duct from home depot... But!!! knowing then what i know now i would have built a water table from the the start, and i am planning on converting it in the near future. Not saying there is anything wrong with the air handler, but what i didnt consider at the time was our climate, the air it is sucking out of my garage through the handler needs to be replaced with air from out side,in warmer months its great, doors wide open etc... when its minus 40 outside, you can imagine what happens to the temperature inside in a short period of time.... I thought about running more duct from outside in over the table for it to draw in air, but after talking to people with water tables, im convinced they are the way to go. Different people have different opinions on the actual water height, some have the water level a few inches below the bottom of the material, some have it a few inches over the top of the material being cut, and others anywhere inbetween... personally i want to make mine so the water level is touching or just over the top of the material, reason being is i think you will still have some smoke and dust with a gap between the material and the water, and also to control warping... I did a test awhile back, i ran a garden hose to the table and sprayed water on the plate as i was cutting, and with the air handler running also( summer )... the difference was amazing... i usually cut 1/16 to 1/8 plate and there was no warping at all and as well as i thought the air handler was performing, there was a huge difference in the reduction of fumes, smoke and dust....only problem is the water runs out the bottom onto the floor and im not going to stand there all day holding a garden hose...
So there are a few things to consider before deciding on air venting or water, or a combination of both... i wish i had researched it more...live and learn.
EDD
Edwardo,
I finally got some pictures of my water table uploaded.
It is just below the slats...
John
Looks Great John
Is the water tray free standing, or did you attach it to the table? Just out of curiousity, you have slots cut along the length of your slats, what are they for? I went back and was reading some post, i also have issues with handling the sheets of steel... and i have been giving it some thought for some time, the 4x8 1/16 and 1/8 are relatively easy to man handle with 2 people, but most of the time i am working alone in my garage, i also dont have the room or height for a small forklift, or the money to buy 1... i have a old suburban truck that i use to haul sheets in, i only buy 4-5 sheets at a time and just leave them in the truck until needed, one thought was to make a rack to store the sheets laying flat, then slide them onto a cart that is the same height as the table, wheel it into the garage and slide the sheet onto the table, this way the sheets are laying flat from the supplier to the table.. i know it sounds like alot of b.s. but i cant think of anything else at the moment.. Im away from home until next week, when i get back i'll try and post some pics as well...
EDD
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