CNC Plasma cutters, DIY, building info and guide

Water table design,

My table incorportates a large water pan made out of 1.6 black steel sheet,



My slat holder mount laps over the pan so the water level can come up to the top of the slats.

To move the water I have used a pump instead of the common approach to pressurize the water tank. This is for safety in a work place environment.



My tank is made from 3mm black sheet, I had the tank galvanised after I made it to ensure it will last a long time.

I have left the top of the tank open to allow easy cleaning of sludge. I was meaning to make covers to stop evaporation but I have used it for about half a year with out them and have not noticed much everporation occurring.

Looks good what you have done. Have you considered a down draft table?
That seems the way to go for commercial work.

When you migrate to Linuxcnc, you'll be able to zone it. I wrote a component to trigger air rams based on the axis position for exactly that purpose. I was going to rewrite it to be more general purpose so you could define any number of zones.

This ram is much bigger than you need, but it gives you an idea how it can be done.

Rod,

Yes I have considered a down draft table,

I decided against it for the following reasons,

Once you have the ducting set up its not easy to move the machine to another spot in the workshop if needed.

Our shed has a eave height of 7 meters and a apex height of 10 meters, Making installing ducting not as easy as a shed with a lower ceiling.

My old control system (CandCNC) did not have provisions for zoning the fan suction, meaning I would either need to design something to work with the controls or have a really large suction fan for the entire table area (4000x2500).

So far I don't really see much of a downside to having a water table apart from water spray when the torch finishes and having to clean out the sludge it hasn't been too painful to work with.

thefabricator03 wrote: Rod,
Yes I have considered a down draft table,

My neighbour purchased a machine from New Zealand before Christmas with 200 amp PowerMax on it. he ducts it straight up with a snail blower beside the table. Our roof is about 7 metres and it did not worry him much (but he already had it there for his previous table.

Anyway, it will be pretty trivial with mesa cards providing enough outputs. The beauty of LInuxcnc is its so extensible. Here is all the code you need for 2 zones utilising a 2 position flap so 4-6 zones would not need much more.
Trivial hey!

Thank you guys,
The only reason i do not like down draft and prefer the water table is that you are putting out heavy fumes made out of vaporised metal and whatever else got burnt in the process for your neighbours to enjoy !
Water table after a long use smells disgusting and that smell stays with you for several days after, but it is much less dangerous.
What about sludge disposal ? Here a local junk yards collects it at 4 to 5 cents per Kg. Not much but much better than throwing it.

No worries Tom,

We have our own small steel scrap bin that we just use for the plasma sludge, we only let it get halfway full otherwise it gets to heavy to pick up with our 5 ton forklift.
There is a lot of weight in steel particles!!

The other reason for the water table is as Tom mentioned, dry cutting produces a lot of smoke, venting to the atmosphere is one option if you dont have neighbours close by otherwise you need to filter the fume output which quickly gets very expensive if you plan on doing it right.


One of the major cost in a commercial laser system is the fume extraction system, but when you can cut just about any material the fumes are more than likely going to be highly toxic,