Precision Plasma 4x4 CNC Table Build

[jjellingson]

you are moving right along, looking really good. I like your idea for slat holders. Don't you just hate cold lap (leaks). It seems like every time we try to save a buck here and there it bites us in the butt. One would still expect a pvc valve not to leak, was this your problem? Or?

[unixadm]

you are moving right along, looking really good. I like your idea for slat holders. Don't you just hate cold lap (leaks). It seems like every time we try to save a buck here and there it bites us in the butt. One would still expect a pvc valve not to leak, was this your problem? Or?

The slat holders were pretty easy to make. I looked at a few ideas, such as using threaded rod with a bunch of washers and nuts to make an adjustable slat system. Drill a hole through the end of each slat, or notch the bottom to slip over the rod. Then I started looking through my pile of steel and decided to go the angle iron route. I've not seen anyone use that method, but I think it's going to work well. It gives roughly 3/4" of engagement to hold the slat. I revised my plans so that I can keep the slats below the level of the pan surround.

The lap joint is what is leaking in a few places. I got the pan cleaned up last night and stuck an old fan blowing downwards right in the center to dry the table. I can see a couple of spots in the weld where I think the leaks are coming from. I'm just going to burn a hotter bead around the entire lap joint in the hopes it will seal up. It can be tough to pinpoint because I have 2.5" of overlap on my sheet and angle iron, and the water can seep under the sheet and run down the angle a bit until it drips. I'm certainly out of practice on welding since I have not been fabricating much over the last five years. I'll get it fixed though.

The PVC ball valves are just a pain to turn, that's why they are junk. I don't have to replace them right away, but I probably will replace them after my testing is completed.

[millman52]

You might want to think about another row of holders down the center of your water tray to hold the slats in a bow. It will help with 2 issues. (1) straight slats can wobble & allow plate being cut to move. (2) when cutting a square part it will keep you from destroying an entire slat if cut happens to center on one.

You'll be amazed how many times #2 will happen. Even curved it's pretty common to muck up 5-6" of a slat.

[unixadm]

The last week or so has been extremely busy with work and with my Mom. She has cancer and it's not exactly a priority to be working around the shop instead of visiting her or talking to her. She had surgery a month ago and starts radiation tomorrow.

As a result, I've had sort of a lack of progress. I was able to get out into the shop/garage/whatever you want to call it yesterday and sealed up the water pan so it is water tight. I then mounted all of the slat holders, and got everything in plane with the upper support rails that will hold the two parallel tracks that the gantry tube rides on (X Axis). I inverted my slat holders and raised them above the water line by about a half an inch. I'm hoping this will reduce water splashing from the table some, as I plan to do most of my cutting towards the center of the table. I tested it both ways using a air nozzle at 90 PSI and they did help quite a bit when I was running the water at a depth near the top of the slats.

Today I spent cutting slats and custom fitting them for a good tight fit. They are tight and in a stiff bow and are not going to move under pressure. The post above did not take into account I was going to bow the slats for that reason and also to just keep them situated tightly. They are stiff enough that most must be installed with a dead blow and some light taps to seat them. All looks good.

I only have a hand full of things to fabricate left before I break the table down for finish work and paint.

1. Bottom Shelf Supports
2. Cable Track brackets and channel
3. CandCNC Control Box mounting, and also a mount point for the DHTC in an ABS box.
4. Wire Management under table.
5. Formed LCD and Keyboard mount. I think I'll use some 1-1/4" 16GA square tubing to form this on my JMR bender since I have a die for that stock size. I'm going to fit it into one of the tubes with a couple of hand knobs so it's removable from the table. I'm going to mount a 17" LCD and probably a wireless keyboard/mouse, and also an E-Stop button.
6. Air regulator and solenoid mount plate for the plate marker I'm building.

I'm still waiting on my Hypertherm CNC interface cable. I got my servo based Taig CNC mill up and running and it's ready to cut some Delrin parts for my plate marker prototype. I'm not going to work on that until the table is functional though. I'll probably preinstall the air lines at final assembly, but nothing else until a later date.

I wish I knew someone with a plasma table to cut me some caster plates for my 1000 lb rated locking casters. I want to incorporate a tongue that sticks out with a gusset against each table leg that I'll weld on a 5/8" nut and use a 8" long 5/8" bolt to act as leveling feet. Maybe I'll do some test cuts prior to painting and see if I can cut my parts for my table, on my own table before it's finished.

[unixadm]

Instead of calling it quits earlier today, I pressed on and got a couple more things done. I have the gantry back on the table so I can mock up the cable tracks. I'm using 3" aluminum channel to contain the track and some 3/16 brackets I had purchased for a gate/entry welding project from Kingmetal. I did a little roughing of the corners into a contour on the Wilton belt grinder. I also cut and tacked the lower shelf cross supports in place.

[jjellingson]

Sorry to hear about your mom, hope things go well.
Your table is looking pretty sharp. You will be cutting before long now. The brass ball valve looks stronger. I know the feeling of not having time to work on a project. Hang in there...

[unixadm]

I spent the last couple of days working part time on the table. My schedule has been very busy so again this project has not gotten the attention it was getting when I started it, however I was on vacation then too. I have completed the cable track channels and tied all of that into the gantry tube. I like the way it came out and my next update will show pictures of what I did. Tomorrow I need to give the pan a quick coat of black paint and clean out the interior. I gave the bottom a good coat of rubberized undercoating as a just in case against leaks. I still have a few items to build, such as a holding tray for my Powermax 45, a mount for the CandCNC control box, and a flat panel to mount air regulators, solenoids, and other misc hardware for the plate marker. I still need to build the monitor and keyboard mount, but I'll wait until the table is operational to do that as I can cut some brackets and make it come out a bit nicer. However all of that stuff is bolt on by design. Lastly Jim Colt cut my caster plates and some gussets for me which should be here early this week. I'll need to remove a bit of paint, weld them on, and then touch up the bottom of the legs and get the caster plates painted. I'll do that with a Preval sprayer though. Until those are mounted I'm not going to reinstall the water pan as the water pan weighs about 250 pounds and isn't much fun moving by myself, nor is lifting the table when it's installed.

I painted the table today, starting with a white primer. This is no odor paint that I bought by the gallon, and is water based. It went on nicely using my HVLP sprayer, and then I sprayed semi-gloss red on top of that using the same process. It's also no odor, and it worked pretty well. It seems to be quite durable. Since I was spraying outdoors and I have neighbors with kids who are always playing near by I wanted to be thoughtful. If I sanded and clear coated it, the shine would be a lot better but that's just too much work.

I also started work on the DHTC box and got the wiring done inside of the Powermax 45. I'm waiting on my Hypertherm CNC interface cable to wrap that up.

Yes the paint is bright, but I don't have anything with much "bling" in the shop so I wanted this table to stand out. lol.

[unixadm]

I reinstalled the gantry rails and tube today and fitted the cable tracks one last time. I spent about 45 minutes adjusting the rails and gantry to get everything dialed in. Once I fully bolt down the rails I'll check again, but I don't expect them to move so it should be a moot issue. The gantry rolls up and down the rails very nicely with full engagement of the V-rollers. Everything looks good, so I'm going to remove the cable tracks, open up the tracks (the top is hinged) so that I can install all of my steppers and machine torch. I'll string everything out on the floor, loosely hook up loop everything, and lay a pull string along side to aid in pulling any addition wire or air tubing in the future. The gantry tube cable track will have the following:

Machine Torch Lead, Two 1/4" Poly Air Lines, Z-Axis Motor Lead, Y-Axis Motor Lead, 18ga 2 Conductor SO Cord for Torch Switch, Pull String

The lower track will have all of the above and:

X-Axis Motor Leads

Once that's done I'll fit all of the parts to the table, do a little soldering, and install the pulleys and gears. I'm going to sit the electronics under the table at first and then figure out a good mounting location. I'm trying to keep the bottom shelf free and clear for sheet storage as necessary, so the control box and plasma will sit off to the side below the cable track channel.

I also got the water pan painted today and all I need to do is weld a couple of bolts onto the bottom so I can ground the pan to the table, and also install a ground clamp lug on the side of the plan for connecting the lead from the plasma cutter. I'll do that tomorrow since it will take about 15 minutes and then the pan can go back into the table as soon as I fit the casters. I'm done for today as I have chores to do.

[unixadm]

Alright, I lied. I pressed on a bit longer and got all of the motors drilled out, mounted, and the torch installed. I may be short on the Z and Y Axis cables even though I had CandCNC extend them. If so, I'll have to extend them on my own, but I'm hoping I can mount the box in a good location that they'll barely reach.

The T45M machine torch looks right at home on the table. I'm starting to see the light at the end of the tunnel.

[Dustin407]

Unixadm,

Your build is coming along exceptionally well i must say... Very nice craftsmanship. You should have a nice running machine when finished. Where did you buy your gantry and belt reduction kits from...? what was the price range on the entire kit?

[millman52]

Unixadm,

Your build is coming along exceptionally well i must say... Very nice craftsmanship. You should have a nice running machine when finished. Where did you buy your gantry and belt reduction kits from...? what was the price range on the entire kit?

Dustin, The kit is from http://precisionplasmallc.com/

I also liked the looks of the kit. Simple & straight forward, Yet very adequate. I was hoping maybe they had a 5' X 12' kit in a front drop side. PP LLC site looks like a 5' X 10' is as large as they are building.


Not to pick the kit apart but for my personal use I'd like to have seen 3:1 or 4:1 reduction options. as I mainly cut 3/8"-1 1/4" material & don't need the speed of a 2:1 reduction. Again Just for me. I think it's one of the most sensable kits for the price i've seen for home shop use.

For a 5 X 10 the kit with reductions is $4000.00 then build the frame & electronics package + software

Keep up the good work unixadm

Neil

[unixadm]

Jim Colt helped me out with the caster plates and tonight I had a bit of time to quickly weld them onto the bottom of the legs and get the casters installed. In reality I wish I had made the table even lower, but I was trying to get usable storage space under the table. So a sacrifice was made, but I think I'm just used to the whole thing being six inches lower to the ground this whole time, and now the table is way up in the air. I guess if I am cutting big pieces of plate, it has to be lifted anyhow so it's not a huge deal. I'm 6' tall, and can easily reach the middle of the table. Food for thought though when people are building the tables. For now with the limited space I need a mobile solution, however if I had more space I can always ditch the casters and just use leveling feet. I threw a quick coat of paint onto the plates with a Preval sprayer - it didn't even get a chance to dry before I installed the casters. I need to get this project done, no time to waste.

Tomorrow the rest of my wiring shows up, so I'll be completing the cable tracks with all of my air lines, wiring, etc. I'm running the air lines for the plate marker I'm working on, but they will not be used initially so those are the orange and red lines in the pics below. I have blue to feed the table and solenoids.