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  • Plasma Cutting Table up and running!

    Been awhile since I've spent time on any forums. Just have had too many things going on. But this, I figured, was worth posting!

    About 10 years ago, I began the process of building a CNC plasma table. Never got very far and it was set aside for other projects. Last winter, I needed some pieces cut and had a tough time finding somebody who would do it for what I thought was a reasonable price. I found somebody to cut them, but I wasn't really happy with the cut quality. I asked around about it and everybody told me that it was just the process. The thing that I was least happy with was all of the rounded corners. I figured if I could cut a square corner by hand, then a computer ought to be able to do it too. So, I got back on the project. I've got quite a few pictures, but they are scattered all over the place, for some reason. I'll try to post them as I come across them.

    For now, here is a video of one of the machine's first cut under computer control.

    http://www.youtube.com/watch?v=zvpUE...&feature=share
    Still building my new old truck - see the progress!
    http://www.ford-trucks.com/forums/65...-coe-idea.html
    http://www.hobartwelders.com/weldtal...ad.php?t=27017

    Square Wave TIG 200 - Woot!
    MM180
    SP125+

  • #2
    The build criteria...

    There were several considerations in the design of this table.

    1. Inexpensive - I was building this on a budget. If I had $5k just laying around, I might have just bought a turnkey system from Torchmate, which by all appearances, is a nice system. But I don't.

    2. Compact - There isn't much room in my shop, so it needed to use only a little bit of real estate.

    3. Inexpensive - I know I already mentioned this, but it's worth mentioning again. I really wanted this to be a budget system.

    4. Accurate - Well, sort of. It's a plasma cutter! I don't need 0.0001" resolution. It just needed to be accurate enough to cut without a bunch of obvious zigzags.
    Still building my new old truck - see the progress!
    http://www.ford-trucks.com/forums/65...-coe-idea.html
    http://www.hobartwelders.com/weldtal...ad.php?t=27017

    Square Wave TIG 200 - Woot!
    MM180
    SP125+

    Comment


    • #3
      Inexpensive...

      Without a lot of extra cash laying around, I started looking at stuff on Ebay. I am amazed at the prices of stuff there sometimes. And I don't get it. How can some of this stuff cost so much?

      Anyway, in the end, I decided on an open-ended belt drive. I'm using steppers from a HP Laserjet III printer. The breakout board is from CNC4PC and the driver board is from HobbyCNC. I've heard that the guy who owns HobbyCNC can be a jerk to deal with, but the purchase went fine and I haven't had a need to deal with him yet. If I end up needing his help, I guess I'll see if there is any truth to those rumors. I am using skate bearings running on steel tubing, which seems to be more than adequate so far.
      Still building my new old truck - see the progress!
      http://www.ford-trucks.com/forums/65...-coe-idea.html
      http://www.hobartwelders.com/weldtal...ad.php?t=27017

      Square Wave TIG 200 - Woot!
      MM180
      SP125+

      Comment


      • #4
        Compact...

        I started out wishing for a 4'x4' table. That means the footprint would have been more like 5'x5' and with room to walk around it, I would have been out about 25 sq. feet more floor. So, I decided to think more about a 4'x2' table. I could always let a sheet hang out of one end. My first attempt at linear motion was the allthread leadscrew, which ended up being about 5' long. When that didn't work, I decided try a shorter version. I still didn't have the speed I wanted, so I gave up for awhile.

        When I got back on this project last winter, I gave it some more thought. I have only cut out a piece larger than 2'x2' once and it was about 1'x4'. So, if I had a 2'x2' table, I could still cut everything I have ever used the O/A torch or the plasma cutter for. Did I really need a full size table? Absolutely not! Turns out making it smaller also makes it less expensive to build. I ended up with a working area of about 26"x28". The overall dimensions of the table itself is about 36"x36", not including the electronics box and the PC. I will build a stand/cart for it so I can move it around as needed and then a separate stand for the PC, to try to keep it out of harm's way a little bit.
        Still building my new old truck - see the progress!
        http://www.ford-trucks.com/forums/65...-coe-idea.html
        http://www.hobartwelders.com/weldtal...ad.php?t=27017

        Square Wave TIG 200 - Woot!
        MM180
        SP125+

        Comment


        • #5
          Accurate enough...

          When I started this with the allthread, I was looking at resolution far greater than I needed, even as a router. After abandoning the idea of a dual-use table, I started thinking real hard about how precise it needed to be. A piece of typical copy paper is about 0.005" thick. Could I tell a difference in a cut of 0.005"? Of course not! On the mill or lathe, I can feel that. Not on a piece of metal whose edge has been melted and recooled. So, in the end I ended up with a pulley with a pitch circumference of 2" and steppers with 200 steps per revolution. 0.010" is plenty. I am microstepping, mainly for a smoother motion, but the side effect is that it does add a bit of resolution. Of course, everybody says not to rely on microstepping for added resolution, since it may not be uniform. Again, I can't tell the difference if it's not.
          Still building my new old truck - see the progress!
          http://www.ford-trucks.com/forums/65...-coe-idea.html
          http://www.hobartwelders.com/weldtal...ad.php?t=27017

          Square Wave TIG 200 - Woot!
          MM180
          SP125+

          Comment


          • #6
            Here are a couple of pics...

            Whole setup after making the first cuts.


            First pieces cut.


            A closer look at the first piece cut.


            I cut 6 of these and they all came out the same! I never could have done that by hand...
            Last edited by whateg0; 09-05-2012, 01:13 AM.
            Still building my new old truck - see the progress!
            http://www.ford-trucks.com/forums/65...-coe-idea.html
            http://www.hobartwelders.com/weldtal...ad.php?t=27017

            Square Wave TIG 200 - Woot!
            MM180
            SP125+

            Comment


            • #7
              A few more pics...

              Computer case gutted and ready for modification.


              I guess it has been a family affair.


              Rear panel machined and now part of the case. (I am anxious to get the CNC mill running next!)
              Still building my new old truck - see the progress!
              http://www.ford-trucks.com/forums/65...-coe-idea.html
              http://www.hobartwelders.com/weldtal...ad.php?t=27017

              Square Wave TIG 200 - Woot!
              MM180
              SP125+

              Comment


              • #8
                Yet more pics...

                Bearings on the X axis. This has since been modified to put 8 bearings in instead of the 6 in the picture.


                This kind of shows how the belt is routed.


                This one shows the Z mounted on the Y as well as showing a little more of the belt for the X.


                This was one of the early attempts. Turns out black pipe and galvanized EMT isn't as smooth as I had hoped.
                Still building my new old truck - see the progress!
                http://www.ford-trucks.com/forums/65...-coe-idea.html
                http://www.hobartwelders.com/weldtal...ad.php?t=27017

                Square Wave TIG 200 - Woot!
                MM180
                SP125+

                Comment


                • #9
                  Video of first cuts!

                  I've watched this a "few" times now. If you want to see it cutting, this was with 0.100" steel. Still need to play with feedrate and current, but it did okay with the settings I had.

                  (Skip to about 45 seconds. The first 45 seconds were me doing things like turning on the air and checking settings.)

                  P1120263 - YouTube
                  Still building my new old truck - see the progress!
                  http://www.ford-trucks.com/forums/65...-coe-idea.html
                  http://www.hobartwelders.com/weldtal...ad.php?t=27017

                  Square Wave TIG 200 - Woot!
                  MM180
                  SP125+

                  Comment


                  • #10
                    The machine torch body came in the mail a couple of days ago, but I haven't gotten around to machining the mounts for it, so for now, this does what it needs to.

                    I'm using LinuxCNC and so far, it's done fine. I did download Mach3, but got scared with all of the installation stuff. LinuxCNC, with the Ubuntu distro was very easy to get set up. The only downside is that its driver support isn't as deep as Windows, so I did have to go with an older version.
                    Still building my new old truck - see the progress!
                    http://www.ford-trucks.com/forums/65...-coe-idea.html
                    http://www.hobartwelders.com/weldtal...ad.php?t=27017

                    Square Wave TIG 200 - Woot!
                    MM180
                    SP125+

                    Comment


                    • #11
                      Originally posted by whateg0 View Post
                      The machine torch body came in the mail a couple of days ago, but I haven't gotten around to machining the mounts for it, so for now, this does what it needs to.

                      I'm using LinuxCNC and so far, it's done fine. I did download Mach3, but got scared with all of the installation stuff. LinuxCNC, with the Ubuntu distro was very easy to get set up. The only downside is that its driver support isn't as deep as Windows, so I did have to go with an older version.
                      Wow! It's great to see someone build things like this, rather than just spending the big bucks! Keep the pictures coming!

                      Comment


                      • #12
                        good to see people do their own tools

                        At work we have made our own 3/4" picket bender many years ago for doing belly pickets. It just uses a 1 hp pump pack from graingers for running the cylinder. it uses gate wheels and 1 guy can do about 3 pickets a minute. We made one a few years ago for putting radius bends in 1" pickets. That took a lot more time and the owner of the company did much of the layout. It uses rollers from gates and a long cylinder to wrap the pickets around a radius and uses a 5 hp pump pack. Maybe 1 1/2 pickets a minute. Stuff like this is not readily available off the pallet. Can have it custom made but the price is prohibitive for a small or medium fence shop. ESPECIALLY ONE IN CALIFORNIA
                        Last edited by gatemaker; 01-11-2013, 10:23 AM.
                        fence and gate shop worker
                        At home...
                        Lincoln Power MIG 180....
                        Winco 6000 watt generator (13 hp Honda) "Big Jake"

                        Comment


                        • #13
                          Originally posted by gatemaker View Post
                          At work we have made our own 3/4" picket bender many years ago for doing belly pickets. It just uses a 1 hp pump pack from graingers for running the cylinder. it uses gate wheels and 1 guy can do about 3 pickets a minute. We made one a few years ago for putting radius bends in 1" pickets. That took a lot more time and the owner of the company did much of the layout. It uses rollers from gates and a long cylinder to wrap the pickets around a radius and uses a 5 hp pump pack. Maybe 1 1/2 pickets a minute. Stuff like this is not readily available off the pallet. Can have it custom made but the price is prohibitive for a small or medium fence shop. ESPECIALLY ONE IN CALIFORNIA
                          Would be nice to see pictures of these machines, if not proprietary!

                          Comment


                          • #14
                            don't own a camera

                            Originally posted by Northweldor View Post
                            Would be nice to see pictures of these machines, if not proprietary!
                            I don't own a digital camera or a cell phone with a camera. I run a bit lean around here. Don't have a penny of debt though!
                            fence and gate shop worker
                            At home...
                            Lincoln Power MIG 180....
                            Winco 6000 watt generator (13 hp Honda) "Big Jake"

                            Comment


                            • #15
                              Originally posted by Northweldor View Post
                              Wow! It's great to see someone build things like this, rather than just spending the big bucks! Keep the pictures coming!
                              Thats me.....
                              I spent the big bucks for the Plasma-Cam DHC. It's sitting in the shipping crate yet. I want to get all the infrastructure complete, I have a new Jim Colt 65 amp (HyperTherm) with Jim's cable for the voltage divider, short barrel machine torch with Ohmic cap and sensor. I had my cousin design and build the drive system plus he integrated a flat bed scanner so I can scan in hard copies of my SolidWorks files, or transfer electronically, whatever the case may be. An IR inline air dryer plus Motorguard on the plasma. I don't want the mess in the shop so I'm doing a downdraft table with makeup air.

                              This year I might get it operational, I might. It wasn't cheap. I never expected it to be. I knew going in that the table was about half of the total cost. I think people don't understand that there are a lot of perhiperal items to take into account.

                              Lets see...
                              Plasma-Cam DHC with enhanced torch control.....10K
                              HyperTherm 65 amp remote controlled plasma....5K
                              Machine torch...900 bucks
                              IR dryer...700 bucks
                              Downdraft system...1K
                              Makeup air system...1K
                              Drive system, with scanner and perhiperals plus a roll around cabinet...4K
                              Miscelaneous plumbing, tin work, and sweat time....1K

                              Basically 20 grand, give or take or about half of what my Haas CNC machining center costs without tooling.

                              Can't put a price on fun.

                              I look at this one (in the pictures) and I'm impressed, but then again, I'm not. Mine has engineering and repeatability at close tolerances (for plasma cutting), something I need for my parts and I'd never fire a torch on a table in my shop without adequate exhaust to the outside. I have precision machines that won't tolerate airborne crap. Precision slideways get contaminated with airborne particles and that destroys the accuracy.

                              So yes, I'm impressed with the ingenuity but in the long view, it won't work in my scenario.
                              So little time...So many machine tools.........
                              www.flipmeisters.com

                              Miller, Hobart & Lincoln TIG/MIG/-
                              Hypertherm Plasma (Thanks Jim)
                              Plasma-Cam DHC (coming shortly)
                              Harris OA
                              Too many motorcycles.............-
                              sigpic

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