After many months or reading and researching I am finally ready to start building a plasma table. So here are the specs.
48.5"X48.5" travel
water tank
369oz steppers
dual drives on the y
Gecko 201 stepper controllers
20 degree 20 pitch rack and pinion
3.75:1 gear reduction
Hiwin 15mm LG rails on the Y and Z
THK HSR25mm rail on the x
CandCNC Digital THC
Mach 3 control.
Hypertherm 1000

The Table will be made from 3x3x.125 square tube so I started milling the cross pieces for the table square and held .001 on length.
http://i122.photobucket.com/albums/o269/bigtoy302/DSC01085.jpg

Then I started drilling and tapping the holes for the 25mm rail for the gantry.
http://i122.photobucket.com/albums/o269/bigtoy302/DSC01086.jpg
http://i122.photobucket.com/albums/o269/bigtoy302/DSC01087.jpg

Next I started on the Z. The Z is .188 HR plate and 15mm Hiwin rails. It will have 6" of travel. The single rail will be used for the floating head for the torch.
http://i122.photobucket.com/albums/o269/bigtoy302/DSC01088.jpg
http://i122.photobucket.com/albums/o269/bigtoy302/DSC01089.jpg

Looking good so far. Thanks for taking us along for your build.
DRL

Welcome to the journey. Judging by your having access to a horizontal boring mill. I'd suspect you have access to all the other machine tools, Lathe(s), Milling machine(s), etc to produce a very fine & detailed Plasma table.

Why the small size?

Why the small size?

I was going to build a 4x8 but I just don't have the shop space and I don't really need anything bigger right now. I know I will kick myself later when I need bigger, but I will build another if it comes down to it.

Oh, I am a Manual machinist in a huge machine shop, so I have access to all the cool machines.:)

I sort of figured space must be an issue. Other than that it just doesn't cost that much more to go bigger. You might want to try & leave 1 end of the table bolt together. That way if you later want to expand to 8' or even longer length it can easily be done.

It sucks not to have enough room for at least a 4 X 8. That way sheets od stock are economical & you don't first either have to have them sheared in 1/2 or cut them down yourself first.

Good to have a new build again!!! Fine start too, paint it while building , after done you´ll not want to take it appart ....

Hey Lamicron, Hows your machine running? Sold it yet? Building another?

Hi Rich! Yes I sold it!!! And sold another 2!! Now Im building two 4x8 and one 4x4 for me, and also one router 4x4, i´m waiting to have the material tomorrow. MAybe start a thread with one of those...´One will be a water table for plasma and a router, i ´ll build it with a rapid table change.
Luis

Rich, where did you buy your pulleys? I need 3:1 pack. and belts. Can you help me with part numbers?
Thanks
Luis

Rich, where did you buy your pulleys? I need 3:1 pack. and belts. Can you help me with part numbers?
Thanks
Luis

Luis rather than keeping Bigtoy's thread hijacked. Start a build log in: Plasma, EDM and other similar machine Project Log & pm me the link to it or I'll find as I'm on practically every day. I'll look for the information & get back to you there later.

Neil

Sorry for that, you are rigth.
Luis

I got a little bit more done today. I got the Y rail holes drilled and tapped, then I welded the frame all together. I still need to weld a sheet on the bottom to form the water tank.

http://i122.photobucket.com/albums/o269/bigtoy302/DSC01093.jpg

the welds
http://i122.photobucket.com/albums/o269/bigtoy302/DSC01092.jpg

holes for the rails.
http://i122.photobucket.com/albums/o269/bigtoy302/DSC01094.jpg

Bigtoy,
I recently came across this site. WOW! I have wanted, but could not justify a toy this expensive for a couple years. The prospect of making a plasma table myself has consumed my spare time. Like you, I am reading everything I can find on the subject. I am working out the details now. I plan on starting the build by early summer ('08). I look forward to your updates. I am a fairly accomplished welder myself and I would like to say your welds are impeccable. It looks like we are neighbors too, as I live in southern Oregon.
---Bob

Beautiful welds

Bigtoy,
I recently came across this site. WOW! I have wanted, but could not justify a toy this expensive for a couple years. The prospect of making a plasma table myself has consumed my spare time. Like you, I am reading everything I can find on the subject. I am working out the details now. I plan on starting the build by early summer ('08). I look forward to your updates. I am a fairly accomplished welder myself and I would like to say your welds are impeccable. It looks like we are neighbors too, as I live in southern Oregon.
---Bob

The fun really begins when you start a build.

I was a total greenhorn when I began. I made up some CAD drawings mainly to keep some of my ideas straight. I was lost for quite some time. I really wanted to have most all my parts gathered up before I started.

There are so many things that depends on the part next to it. What do I need to buy so I don't build myself into a corner? Is this heavy enough, Is that strong enough? If I buy this rack & pinion, What belt reduction ratio do I need. Darn I actually would like to have my motors in hand so I can build the drives as small as practical yet rugged & strong.

All these things & trying to think things through to the end took many hours of head scratching & decision making. The time thinking paid off though in not having to un-do progress already made.

Looking back I could easily build a second table. Mine has worked out great so far. If I were to start over there is a few things I'd do different but not many.

I made some caps for the legs so I could screw so adjustable roller feet in them.
http://i122.photobucket.com/albums/o269/bigtoy302/DSC01096.jpg

Then I got the bottom of the table sealed off with a piece of 16 gauge. I welded
small beads all the way around and let each one cool to try and reduce warping.
http://i122.photobucket.com/albums/o269/bigtoy302/DSC01097.jpg

Here are my gantry side plates all cut out.
http://i122.photobucket.com/albums/o269/bigtoy302/DSC01095.jpg

I then started working on the Z axis acme screw. The bearing blocks where machined for a 608 bearing. The acme screw is a 1/2-10 single single start screw. The nut is a delrin nut from Dumpster CNC.
http://i122.photobucket.com/albums/o269/bigtoy302/DSC01099.jpg
http://i122.photobucket.com/albums/o269/bigtoy302/DSC01100.jpg
http://i122.photobucket.com/albums/o269/bigtoy302/DSC01098.jpg

Today I had to straighten the table. It had warped about .125 all the way around in the center of the tubes. I did the old heat and quench trick to shrink the top back down. This method worked really good.
http://i122.photobucket.com/albums/o269/bigtoy302/DSC01101.jpg

Then I mounted the rails and welded the gantry tube to the side plates.
http://i122.photobucket.com/albums/o269/bigtoy302/DSC01103.jpg
http://i122.photobucket.com/albums/o269/bigtoy302/DSC01102.jpg

Now after I had the gantry all welded together I totally understand what racking is. I am sure glad I didn't cheap out and not buy a extra motor to dual drive the Y.

Today I had to straighten the table. It had warped about .125 all the way around in the center of the tubes. I did the old heat and quench trick to shrink the top back down. This method worked really good.
Now after I had the gantry all welded together I totally understand what racking is. I am sure glad I didn't cheap out and not buy a extra motor to dual drive the Y.

Have no fear the dual slaved drive will completely eliminate the racking. Mine seemed limp as a noodle. everyone that saw it said it would never work. When you get everything hooked up & power on the motors you'll be amazed how solid it becomes.

Neil

So, today I got the belt drives, racks and the Z mounted. I Also tested the water tank to make sure I had no leaks. I added some tubes on the bottoms of the legs for more support. With nothing there the table was just to shaky. I still have some finish weld and I still need to make the slat holders, but other wiring and paint it's almost done.
http://i122.photobucket.com/albums/o269/bigtoy302/DSC01104.jpg
http://i122.photobucket.com/albums/o269/bigtoy302/DSC01105.jpg
http://i122.photobucket.com/albums/o269/bigtoy302/DSC01106.jpg
http://i122.photobucket.com/albums/o269/bigtoy302/DSC01107.jpg
http://i122.photobucket.com/albums/o269/bigtoy302/DSC01108.jpg
http://i122.photobucket.com/albums/o269/bigtoy302/DSC01109.jpg

Bigtoy,
I don't understand your Z axis. It appears to have 2 slide systems and only one of them is powered. Does the other float? Will it eventually be powered? Your table looks great! One last question, do you know how much the gantry assembly weighs?
Thanks,
Bob

Bigtoy,
I don't understand your Z axis. It appears to have 2 slide systems and only one of them is powered. Does the other float? Will it eventually be powered? Your table looks great! One last question, do you know how much the gantry assembly weighs?
Thanks,
Bob

Bob, The single rail is for the floating head. I have not weighed the gantry yet.

So, today I made the slat holders and put them in. I used 3/8 round welded to the sides to hold the slats and I cut the slats a little long so they would bow a bit. I then made all the mounts to hold the cable carriers on.

http://i122.photobucket.com/albums/o269/bigtoy302/DSC01121.jpg
http://i122.photobucket.com/albums/o269/bigtoy302/DSC01122.jpg
http://i122.photobucket.com/albums/o269/bigtoy302/DSC01123.jpg

A couple of suggestions......
Is it a good idea to have the slats going right down to the bottom of the tank?
My tank has the slats sitting off of the bottom by about an inch.
Also having each slat sectioned off won't allow the water to circulate, and in well used sections won't the water get contaminated very quickly???

Are you going to 'sawtooth' the tops of the slats?
I think just having the flat edges you may get problems with the parts 'welding' themselves to the slat edge???
I have my slats 'sawtoothed on both sides, and I can turn over when they get too worn out.

How are you running the dual motors?
I am toying with the idea of building a Mark 2 Plasma machine. I need to be able to cut a 2000mm (80") x 1000mm (40") Stock sheet.
I think I will need to use dual motors on the X Axis, so do you hardwire them or setup separate motor setups in mach and drive them together???

Andy

I think I will need to use dual motors on the X Axis, so do you hardwire them or setup separate motor setups in mach and drive them together???

Andy

Andy, you use (2) motors & (2) drivers, wired seperately just as if it were a complete seperate axis. Then in Mach, motor slaving, slave the second axis (usually A) to X. other than having them tuned exactly the same & making sure the rotation is correct. That's all there is to a dual drive.

Wow you are further along than me..

So is it really a benefit to run a water table?

Also, what kind of linear guide is that for the X axis?

Also, why did you go steel material on the gantry? Do you think all that mass will slow the machine down?

A couple of suggestions......
Is it a good idea to have the slats going right down to the bottom of the tank?
My tank has the slats sitting off of the bottom by about an inch.
Also having each slat sectioned off won't allow the water to circulate, and in well used sections won't the water get contaminated very quickly???

Are you going to 'sawtooth' the tops of the slats?
I think just having the flat edges you may get problems with the parts 'welding' themselves to the slat edge???
I have my slats 'sawtoothed on both sides, and I can turn over when they get too worn out.

How are you running the dual motors?
I am toying with the idea of building a Mark 2 Plasma machine. I need to be able to cut a 2000mm (80") x 1000mm (40") Stock sheet.
I think I will need to use dual motors on the X Axis, so do you hardwire them or setup separate motor setups in mach and drive them together???

Andy

The slats do touch the bottom but when you put the water in the bottom of the tank bows a little bit under the slats so there is a little bit of room for cirulation. I am leaving the slats flat. I think most setups use flat slats so I don't think it's going to be a problem.

Bigtoy302, Great looking job Keep up the great work & you'll be making the sparks fly in notime.

Neil

I did not get a whole lot done this weekend but I did get it put back together and started the wiring.

http://i122.photobucket.com/albums/o269/bigtoy302/DSC01128.jpg

Switch installed for the floating head.
http://i122.photobucket.com/albums/o269/bigtoy302/DSC01129.jpg

This weekend I got the control cabinet all wired up. I still have to mount a few home switches but thats it. I used some 60mm amd heatsinks and fans for the geckos. I then mounted them to the back of the box.
http://i122.photobucket.com/albums/o269/bigtoy302/DSC01137.jpg
http://i122.photobucket.com/albums/o269/bigtoy302/DSC01138.jpg
http://i122.photobucket.com/albums/o269/bigtoy302/DSC01139.jpg

Real professional job! What other components are needed in the box, and what did you choose? The Geckos are obvious but I don't know enough about them to recognize the others. Thanks for this build thread keep the updates coming!!
Dick

Do you have other hole(s) in the box to let cooling air in/out? Are you going to filter the cooling air in some manner?

Nice looking job on your control box. Since it's metal are you going to insulate it from the table to help keep ground noise down?

Do you have other hole(s) in the box to let cooling air in/out? Are you going to filter the cooling air in some manner?

Nice looking job on your control box. Since it's metal are you going to insulate it from the table to help keep ground noise down?

There is a good size hole in the botom of the box. I dont have any plans on filters. I will insulate the box if noise becomes a issue.

Impressive build; thanks for documenting it. Makes it look easy!

I'm just starting research, sorry if this is an obvious question - can you/someone help me understand what the concept behind the floating head mechanism is and how it works in conjuction with the Z axis? (I've never seen a water table up close in action, so that may be why I can't picture what it's for)

Thanks-
ed

Impressive build; thanks for documenting it. Makes it look easy!

I'm just starting research, sorry if this is an obvious question - can you/someone help me understand what the concept behind the floating head mechanism is and how it works in conjuction with the Z axis? (I've never seen a water table up close in action, so that may be why I can't picture what it's for)

Thanks-
ed
The floating head is for automatically finding the top of the metal. You tell mach how far it travels before it trips the switch then it automatically goes down until the switch is tripped then goes up the specified amount + peirce hieght and starts the cut.

Thanks for the explanation, bigtoy. Your description, along w/ your pic in post #29 makes sense. After the limit switch is tripped, is there some sort of holding mechanism (e.g. electromechanical clamp) that freezes the slide in that position so when the Z axis is raised, the torch raises with it? Put another way, what keeps the torch head from staying rested on the metal, while the Z axis raises and lowers?

thanks-
ed

It looks great! What is the current status?
I am looking a a build, and am interested in your project.

It looks great! What is the current status?
I am looking a a build, and am interested in your project.

I have been pretty busy doing other stuff lately so I have not worked on it in a few months but I will try to finish it in the next couple weeks.

So today I got some more time to work on the table. After many hours of trying to get the second parallel port card installed I finally got it. I got it all hooked up and spun the motors for the first time. Hopefully this weekend I can cut some metal.

Good luck, well built machine.

Good progress please keep us posted.

So after many more hours of frustration with the parallel port card not working properly I reinstalled the drivers and everything started working like is supposed to. I Filled the table up with Plasma Quench and cut a test piece. Everything worked good.
http://i122.photobucket.com/albums/o269/bigtoy302/DSC01144.jpg
http://i122.photobucket.com/albums/o269/bigtoy302/DSC01141.jpg

I cut this piece from 16 gauge at 40 amps and 120IPM.
http://i122.photobucket.com/albums/o269/bigtoy302/DSC01142.jpg

Here is a video of the part being cut.
http://i122.photobucket.com/albums/o269/bigtoy302/th_MOV01147.jpg (http://s122.photobucket.com/albums/o269/bigtoy302/?action=view&current=MOV01147.flv)

Congratulations on completing your excellent build & making those first cuts!:)

The nice clear photos & video are sure to inspire others. Thanks for sharing.