Just got home with the table! Tomorrow is hopefully setup day.
Just got home with the table! Tomorrow is hopefully setup day.
Put the legs back on today, but that's the extent of progress--I need to dust off an old laptop for Mach3 duty before I go much further. 
newrider3 said:In reply to TVR Scott :
Could you share your downdraft table? I'd like to make the switch from a water table eventually also.
Of course!
Like the rest of my machine, the downdraft set-up was mostly scrounged. The dust extractor I bought off craigslist for $50 and looks like it came out of a commercial sawmill. It's big! I used to have it on a full-sized 55 gal drum, but I needed space and cut the barrel down. Realistically you don't need a big tray for dust and stuff, though it's nice to have a place for the heavy particles to collect.
The sheet metal cone on the bottom of the table is just galvanized flashing. I had it left over from another project and just cut and bent it to the right shape. Rivets hold it together and aluminum foil-tape works great for sealing out the sparks and gases.
The duct going into the exhaust fan is drier-vent type stuff. You need metal here - plastic duct will definitely melt.
On the fan outlet the 4" plastic duct has been fine. I shove the duct out my garage window when in use. I used to shove it under a gap in the garage door, but I moved it to the other side of the shop.
Make sure you have some sort of simple grate for catching parts:
Plasma "gunk" will build up on the inside of the cone. You can scrape it off in chunks when you want a job that's soothing and mindless.
For control, I just flip the fan switch before I push "GO" on the CNC. No need to tie it into an output or something.
Any other questions? If you're ever in South Denver near DU you're totally welcome to drop in and check it out.
In reply to TVR Scott :
That's excellent, thanks! I was wondering what kind of baffling might be needed to arrest the sparks before the blower fan, but the catch drum on the bottom makes sense.
I made some more progress tonight. Successfully installed and configured Windows 10 and Mach 3 on an ancient toughbook, and the machine moves under its own power!
I set this up with a different laptop from my CNC for a few reasons. First, I didn't want to screw up the existing setup. Second, I want to be able to use both at once. Third, I know this will be easier to sell if it comes ready to cut out of the box (I'm not planning to get rid of this, but I have a hunch I'll outgrow it eventually). Fourth, the toughbook is the only thing I'm willing to keep this close to sparks and water. And lastly, I need to justify my tendency to hoard old laptops.
Now that I'd proved the computer and the machine were talking to each other, I soldered up an adapter to the plasma cutter and confirmed that Mach 3 could turn the torch on and off. It's bed time tonight, but hopefully tomorrow I'll make my first test cut!
The wording on this imported plasma cutter's warning labels isn't filling me with confidence. 
The finest China equipment comes with the best warnings. Can't wait to see this thing in action. I've looked at the Langmuir tables before but I don't have the space now. Maybe at the new house eventually.
So I'm sending challenge car part requests and stolen stop signs to what address?
Okay, finally had a few hours to work on this project again.
First up, compressed air. My shop is plumbed to an awesome Eastwood scroll compressor, but I keep the shop air at around 150 psi to run air tools. This cheap plasma cutter requires a maximum of 75 psi, and I need to be able to adjust air pressure even lower for most cuts. And, because it's a cheap plasma... there is no regulator built in.
To Lowe's we go! I picked up a regulator and a drier to ensure I'd be feeding the plasma dry air at the proper pressure.
With air sorted, it was finally time for a test cut. I didn't worry much about cable routing or how I arranged the plasma, machine or laptop. And I didn't make my own cut file either. My only goal was to figure out if I finally had all the pieces to cut parts. I threw a scrap of steel on the bed, filled the water table, and hit run...
Success!
I pretty quickly learned that while this plasma cutter is advertised as being compatible with 115 or 230v, it's not really--on low power I blew my 20A 115v breaker twice, then gave up and plugged in the sketchy adapter to use a real welding outlet.
With that sorted, I ran the file. This is a random "ready to cut" download from Langmuir's FireShare website, and should result in a grinder bracket when it's done. Mostly, it's a small part and using a pre-built file removes variables from the equation. I'll learn Fusion 360's Plasma CAM another night.
First few partial attempts one on top of another, playing with torch height, air pressure and power:
And a final "real" attempt:
With that, I turned everything off and called it a night.
What did I learn? Well, I learned the machine, laptop and plasma cutter were all playing nicely, and I learned a bit about what big swings with each adjustment knob look like on the steel. The next step is to dial in the settings for clean cuts, but I'm real happy with the progress so far.
Oh, and I need to condense all of this into a more compact package. Fortunately, I have a plasma table that's perfect for building mounts and brackets. This thing needs a laptop stand and a shelf for the plasma cutter so it doesn't take over an entire corner of my shop and require a bunch of setup every time I use it.
Judging by the mount of water in your airlines, you should purchase air dryer for your compressor. Your air tank reserve is most likely bare steel on the inside plus air tools and water don't play nice together.
The compressor has an electric drain and a (mostly ineffective, I'll admit) air dryer on it; I think that's just some condensation from the outlet drop since I don't use that port very often. I should probably add another dryer where the air enters the building.
It could be possible that the air dryer is in need of a recharge or cleaning? Are they not similar to a A/C unit?
Bumped by a canoe. But this is a good excuse to post my most recent project for the plasma table.
I needed to re-do a set of seat mounts in Tim's Mustang. The floor was pretty rough after 60 years, so I scanned it and then plasma-cut a set of plates to build a flat platform. The future is sweet!
You'll need to log in to post.
