Xalky's cnc plasma table build log.

[xalky]

This project started when I bought a multipurpose Tig/stick/plasma chicom machine. I won't get into the brand because I don't have too many good things to say about it. I went onto some web sites and saw that a few people had built cnc tables for thier plasma cutters and thought to myself "hey, I can do that". So here are some photos of the build, some of the trials as i went along, and hopefully you guys will see me finish it as it is not finished yet, but getting real close.

I designed this thing on graph paper, no fancy Solidworks here. My philosophy is Kiss, "keep it simple stupid". You' will see this. If I can buy a part for $10 that'll do the job, I'm not gonna spend 5 hrs making it on my lathe or Bridgeport.

I designed this to be able to have a max sheet capacity of 4'x4'6". It had to be Light weight, easily movable and dismantleable. It had to cut as well as the offerings from the table manufacturers in the $10,000 range and I also wanted it to double as a light router machine. And now it seems that 3D modeling is well within reach for the home machinist. For those of you that don't know what 3d modeling is. Its those machines that extrude a plastic compound in thin sheets to form a computer generated 3d part out of plastic.
So here's some pictures of the Build.
This is a mockup of one of the gantry ends. The Gantry is made up almost entirely of aluminum to keep the weight down for rapid acceleration speeds, which is vital for cutting thin sheet material:

This is a picture of one of the Gantry ends welded and machined and partially assembled. That was my first time Tig welding aluminum. :


This is a picture of one end of the Gantry attached to the Beam:


Overall picture of the same:


A couple of side views:




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[jumps4]

that looks good
what type of drive will it be and steppers or servos?
what are you planning for the cutting support surface?
what software?
steve

 

[xalky]

Here's a picture of the table beginning to take shape. Notice the legs are bolted together for easy storage or moving to a new location. The Gantry slides right off the rails. The table dismantles into 4 sections.


Here's a photo of the floating torch head so that the machine can find the z location of the plate. This table will have Torch Height Control (THC). The table can find the height of the plate or sheet at various intervals and account for sheet warpage etc... and still maintain optimum torch height for best cut quality.


This table uses timing belts for movement and it also uses 4 to1 belt drive reduction so that table movement is at approx 1" travel per revolution of steppers. This ratio seems to be about optimum for plasma cutting in general for best torque usage and acceleration characteristics. At least that's what I've been told by many smarter than myself. The idler bearings are just roller skate bearings. The Bearings for the Gear reduction mechs are Pillow block bearings minus the pillow blocks. The belt guides are just Fender washers drilled out and spaced off the bearings.



Here's an overall picture of the table as it sits right now:


I'm using the CandCNC Bladerunner drive kit which includes THC in the Package. I did a lot of research on this part of the build. Bar none, these guys offer the best value, and knowledge, and tech support for a plasma table setup.


Here's the front view of the control cabinet:


Here's a view of the back of the cabinet. I had to cut out the back to fit the Dell workstation Tower computer. Then i made a sort of Faraday cage out of insect screening for the back to divert the plasma electronic noise away from the electronics. The cabinet, and computer are all grounded to a seperate ground rod pounded into my garage floor.

 

[xalky]

that looks good
what type of drive will it be and steppers or servos?
what are you planning for the cutting support surface?
what software?
steve

It's steppers driven by timing belts.
The CandCNC controls use mach3 and Sheetcam. They include all the macros for torch height control in the package. Shetcam is an easy to use software thet takes DXF files and translates them to Mach3 but also it's designed specifically for plasma cutting so it's easy to set tool paths,Kerf widths, lead ins and lead outs for plasma.

 

[xalky]

So this is pretty much where I'm at now. The chicom plasma machine was wreaking havoc with HF noise. I blew several boards in the control panel because of that machine. CandCNC was gracious and stumped as to why that machine kept blowing boards out. To make a long frustrating story short. I bought a Hypertherm Powermax85 plasma machine with the machine torch. Tom over at CandCNC actually bought my new/old chicom machine to run tests and find out what the hell the problem was. The preliminary verdict is that the chicom multipurpose machine used the same HF start as the tig portion of that machine which could interrupt satelite communications within a 1 mile radius... exaggerating a little but you get my point. The hypertherm is miles ahead of the chicom. It uses blowback start and has a cnc connection on the back which CandCNCs hardware and software macros integrate into. A fault anywhere along the line can be seen on the mach screen. A fault on the controller will shut down the hypertherm.

My second set of new boards just came in yesterday so I'll be plugging those in and setting up the controls for the Hypertherm. This is the reason why I highly recommend CandCNC, they helped me out tremendously and they guarantee thier stuff for 2 yrs. I would have been out a lot of cash for replacement boards.

 

[jumps4]

you have a well thought out project going
cant wait to see sparks
earlier you mentioned thin material have you seen the factory thin sheet machines using water misters to keep the material wet. it doesnt effect the plasma but greatly reduces deformation and sparks.
i found it searching for 'cutting sheet metal" in youtube "they are fast"
steve

 

[xalky]

you have a well thought out project going
cant wait to see sparks
earlier you mentioned thin material have you seen the factory thin sheet machines using water misters to keep the material wet. it doesnt effect the plasma but greatly reduces deformation and sparks.
i found it searching for 'cutting sheet metal" in youtube "they are fast"
steve

I did actually. There is some debate as to consumable life with water. I haven't gotten that far yet. Right now I'm gearing up to make this a downdraft table to keep the air in the shop breathable. The downdraft setup I'm gonna be doing is also gonna be extremely simple and fairly cheap to implement and , in keeping with the theme, easy to take apart and put away.

Many plasma table builders are using a water table for dust and fume control, and some are using a combination of both. I like the mist idea and as I continue this build, It would be fairly easy to setup on my machine even with the downdraft. So that very well maybe in the future for this table. And it'd be easy to take apart. Do you have a link for the water mister video?

The reason why I'm stressing the "easy to take apart"and "Light weight" theme is that Real Estate is extremely valuable in my 2 car garage as, I suspect, it is probably for most hobby guys.

This table is fast, no sparks yet but I've put it through a few dry runs already. I suspect it will cut the thinnest of sheet metal with nice sharp corners, thats what the acceleration is for, nice sharp corners on thin material. Acceleration becomes less important as the material gets thicker. The Hypertherm I have will be able to pierce up to 3/4" material with the torch height control once it's dialed in.

 

[jumps4]

here is a machine that is fast
steve
[video]http://v.youku.com/v_show/id_XMjQ4NTI3NDg4.html[/video]

 

[xalky]

First table movement running a program. I'm all tingly. This has been a long time coming. Don't mind the braided cable hanging over the gantry, thats getting removed. Remnants of trying to get the chicom machine to behave.



http://s1124.photobucket.com/albums/l573/xalky99/?action=view&current=video-2012-06-23-20-51-39.mp4



I never posted a video before, hope it works.

 

[jumps4]

it runs good and fast
the toothed ribbon makes it really quiet
steve