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Hello All!I've been lurking for quite a while now and I'd like to thank everybody on here for all the great info and advice. I've finally started building my CNC table with the shopdroids 5.0 gantry kit. The frame is MIG welded 2" square tubing. While I'm totally new to the world of welding and fabrication, I have a hobbyist's background in 3d design, electronics, and programming, so I'm really enjoying this as a learning experience.Here's where I'm at:Here's where I'm hoping to end up:As you can see, these are still very much early days. Any input (even the "pointing and laughing" type) is greatly appreciated.Thanks!MeatWagon: Total NOOB!! 4x8 cnc plasma table build in progress here!
Reply:i think from just seein other ppl's cncs that maybe you should have it closer to the water. just what i noticed.
Reply:My z axis has more travel than some other machines. I wanted to have some space in case I wanted to put a spindle on the gantry and do some milling or routing.MeatWagon: Total NOOB!! 4x8 cnc plasma table build in progress here!
Reply:Subsribing!
Reply:Cool. I've got one of the older PlasmaBot kits (early 2011 vintage - I think it's the 3.0) that I made into a 5' x 5' (it'll cut clear off the edges of a 5' x 5' sheet). Poor girl's been collecting dust lately - I've been so busy with other crap. I only have a small water tray under it right now (3' x 3' - it was a big electrical box that I welded the holes/seams shut). I've got material for a 64" x 64" water tray - I just need to weld it together. If you talk to John, tell him to get the forum back up again.Last edited by dbotos; 07-19-2013 at 11:02 PM.
Reply:Hey Meat Looks like a good start many of us have built our own tables. Hobbies are for us to learn and have fun not much pointing and laughing here. If you hit a snag just ask there are many answers to be had here all are good you just pick the one that fits you. Some build a plasma table only other add routers for wood working and aluminum milling or plate marker. Like all good tool the CNC table will open a new avenue to enjoy.Tom
Reply:Thanks for the interest and support guys! Originally Posted by dbotosI've got material for a 64" x 64" water tray - I just need to weld it together. If you talk to John, tell him to get the forum back up again.
Reply:Just got an email from John. He said he's moving to another state and he's not sure if the store is going to come back or not.. Did manage to get my touch and go plate ordered though, so that's good.MeatWagon: Total NOOB!! 4x8 cnc plasma table build in progress here!
Reply:Originally Posted by MeatWagonWhat material are you using for your water tray dbotos?
Reply:Originally Posted by MeatWagonJust got an email from John. He said he's moving to another state and he's not sure if the store is going to come back or not.. Did manage to get my touch and go plate ordered though, so that's good.
Reply:Originally Posted by dbotos1/8" carbon steel. Tray's gonna weigh about 200 pounds and then 3 inches of water would be another 440. I think I'm going to build some kind of independent structure to support it...
Reply:Originally Posted by dbotosCool. I've got one of the older PlasmaBot kits (early 2011 vintage - I think it's the 3.0) that I made into a 5' x 5' (it'll cut clear off the edges of a 5' x 5' sheet). Poor girl's been collecting dust lately - I've been so busy with other crap. I only have a small water tray under it right now (3' x 3' - it was a big electrical box that I welded the holes/seams shut). I've got material for a 64" x 64" water tray - I just need to weld it together. If you talk to John, tell him to get the forum back up again.
Reply:I built mine out of 18 Ga. plane steel, 4' V 4' with 4-1/4" sides. Your table just need good supports to hold up the water weight. You don't want to weld on galvanize. Attached Images
Reply:Originally Posted by MeatWagonIndependent structure sounds like a good idea... Does everybody build the water tables so heavily or did you just get a really good deal on some 1/8" steel? Seems like I saw another build where someone was using galvanized steel and even one using aluminum. Guess I figured the frame of the table was supporting the weight of the water and the work piece. What am I missing?
Reply:Originally Posted by VirginiaI really like that!
Reply:Howdy folks!Time for an update:Just did a bit of analysis on my blog about the different options for the motors and controlling electronics for my table. Basically I figure it'll cost me about $300 more to go with the candcnc Dragon Cut Kit vs. sourcing the parts (including the Proma THC) separately and building it myself. That doesn't take into account my time or the support offered by Tom, who answered one of my emails within an hour a couple days ago. Pretty sure that's the route I'm going to take.I finally got the rest of my steel up to Juneau a couple weeks ago, but I've had family in town so all I've gotten done is to weld up the other end of the base. I've got all the tubing cut for both sides though, so I should have those welded up soon.I ordered the rest of the hardware today, so things are really coming along!If anyone has any input about the electronics end of things I'd love to hear it. Planning on placing that order very soon...MeatWagon: Total NOOB!! 4x8 cnc plasma table build in progress here!
Reply:Get something with initial height sensing. Still trying to see if there's some way I can do ohmic with what I've got. Probably would have been easier if I had planned it from the beginning.
Reply:Warning, lots of text because CNC plasma is kinda my thing: Originally Posted by MeatWagonIf anyone has any input about the electronics end of things I'd love to hear it. Planning on placing that order very soon...
Reply:Can the Mesa stuff do initial height sensing? I feel like that's the biggest thing I'm missing right now (aside from free time to actually use my machine).
Reply:Some very good info from the Moderator, but not all of us has the boss paying for the build. I am on my third table build and as a DIY guy like many here I need to watch my money. I knew nothing about CNC plasma cutters but jumped in and must say I have really enjoyed these projects and have learned much in the process. I do not share his opinion about Mach 3 or the Proma THC. I had to learn to use CAD, Cam and Mach 3 from scratch and am happy not to include Linux CNC to that I have nothing against Linux but working in windows seemed easier.I gathered up parts from different vender and some info from the web for my builds and I am very happy with the results. This may not be for all but worked very well for me if you do it from the ground up you can find solutions as you have a better understanding of the operations. Different strokes thing.lst thing I cut 24" x 26" x 18Ga. Attached ImagesLast edited by acourtjester; 08-12-2013 at 04:55 PM.
Reply:That's a nice first piece! Mine was a business-card sized rectangle of thin sheet with a 1/4" hole in it (I use them for powdercoating sample plates and figured it'd be a good simple test piece). I still have it downstairs, complete with the pause marks around the perimeter where it wasn't getting the ARC OK signal good enough and kept pausing. I'm in the same boat as you as far as being a self-financed build, but I have almost 20 years of CAD experience and a couple of years of CAM at multiple companies. I went with SheetCAM and Mach3 because those seemed like the popular choice among DIY plasma folks. Certainly not what I had used in a commercial setting, but also nowhere near the price of those commercial CAM packages.I'd be curious to hear more about the LinuxCNC and Mesa hardware. Maybe some screenshots or a video of it doing 2D plasma stuff. Obviously the LinuxCNC is free and the Mesa hardware looks reasonably-priced (~$270 for everything Tensaiteki mentioned). I paid more than that just for my LCTHC and G540 interface card from CandCNC.P.S. Tensaiteki - what CAM software are you using? Is it Linux-based too or Windows?Last edited by dbotos; 08-12-2013 at 09:48 PM.
Reply:Originally Posted by TensaitekiThe 5i25 goes in the computer. It looks a lot like any other PCI parallel port card except it is way better. It is specifically made for running CNC machines.The 7i76 connects to the 5i25 and acts like a breakout board/card. It supplies step and direction signals for up to 5 axis. The step/dir signals are what you send to the motor drivers like Geckos.
Reply:The three main types of initial height sensing, as I understand them are (I think all have been refered to as "touch-n-go" at some point):1) ohmicTorch moves down till tip/shield touches metal workpiece and makes electrical contact. That contact triggers system to set z = 0 then retract torch back up to pierce height. Usually requires special shield or clip with tab to hook wire up to (do google image serach for "ohmic clip"). Also, special electronics are required to isolate that wire coming back to the electronics so you don't fry stuff when you fire the arc and start cutting (i.e. you want it electrically connected while sensing the material, but then you want to isolate it before you fire the torch). Also, material needs to be clean to get good electrical contact.2) torque sensingTorch moves down until it contacts material. As the Z-axis drive motor encounters physical resistance, it draws more current. When the current hits some preset threshold value, the software/electronics set the z = 0 and then retract the torch back up to pierce height. Works best on thicker materials (thinner materials can bow before hitting threshold current and the torch ends up closer than you want when piercing.3) floating torch with microswitchThe torch rides on a secondary set of rails/guides which in turn ride on the main z-axis rails/guides. The torch is held at the bottom end of the secondary rails/guides by a spring. The torch (and secondary rails/guides) moves down on the main rails/guides and contacts material. The z-axis drive continues to drive down, but due to the secondary set of rails/guides, the torch stays still relative to the material but moves up relative to the secondary rails/guides. At a certain point, a microswitch mounted on the secondary rails/guides is tripped. The distance between that trip point and the bottom of the secondary travel is known, so the software/electronics command the torch to retract back up that distance plus the pierce height. This method seems to be the most popular to implement in a DIY build.Last edited by dbotos; 08-13-2013 at 07:52 PM.
Reply:I used the floating torch method on the 2 I built works great, you just wire it into the limit switch circuit. I have all my limits in series set to NC when mach 3 moves an axis and see the circuit open what ever it was doing stops. This works for home or limits or the touch and go motion. Another guy gave me the info on modifying SheetCams post process so it puts a touch and go after each move after a cut operation.I do the setup of the part in SheetCam and then do post processing to make the G-code with the touch and go just where I what it automatically Attached Images
Reply:here is what it looks like in the G-codeN0100 M06 T3 F80.0 (plasma thin metal)N0110 G00 Z1.0000N0120 X17.1116 Y6.1671N0130 Z0.1400N0140 G90F30N0150 G28.1 Z0.50N0160 G92 Z0N0170 G0 z0.25N0180 Z0.1400N0190 M03N0200 G04 P0.3N0210 G01 Z0.0650 F3.937N0220 G02 X17.1864 Y6.1466 I-0.0222 J-0.2275 F80.0Originally Posted by dbotosCan the Mesa stuff do initial height sensing? I feel like that's the biggest thing I'm missing right now (aside from free time to actually use my machine).
Reply:Well I guess we have been told how wrong we can be. Sorry Tensaiteki this 70 year old will continue with my larger table build on the same path as the other 2 because it works very well for me. If its not broke why change? Nothing wrong with what you say but there is always another way to skin a cat.
Reply:I have the 4.0 kit that I am reworking. I originally used 2x2 square mild steel for my rails. When I cut my table down to a 5'x5' I ordered 2x2 aluminum square tubing for my new rails. I cannot begin to describe how much better the carriages slide on the aluminum rails over the steel rails. I never felt the table ran as smooth as it should have, but now I can tell it will run much better.
Reply:My two cents on Linux CNC:I converted two machines (a mill and a lathe) to LCNC and had a good experiance over all. There was definitely a learning curve on the first machine but the second went much faster. There is good support on the LCNC Forum for both the Mesa hardware and the LCNC software. It was not painless, from what I have heard the Mach setup is easier but both machines run at significantly higher rapids then they did with the previous controller and it just works. I have never installed Mach so I will not comment on that. I hope to do a plasma table in the next couple of years and when I do I will use LinuxCNC along with Mesa hardware.
Reply:Hey folks. Thanks for all the input. I haven't really had a chance to look into LCNC thoroughly yet. Been flying like crazy the last couple weeks.Did make it over to the hangar to make some wheel brackets and I finally have all four sides of the table's base completed. Next is to tack them all together. Here are a couple pics.More on my blog. Wheel brackets:This is the frame for one of the table's sides. Can anyone tell me why my fillet welds are getting gouged out like this from time to time?Finally got my bearings and hardware and put together my gantry brackets:Self Portrait:Stay tuned!MeatWagon: Total NOOB!! 4x8 cnc plasma table build in progress here!
Reply:Really screwed up a weld this week. Spent a whole afternoon fixing it. More pics and explanation here.Hey Tensaiteki, Been looking at the mesa electronics. Pretty tempting. Which motor controllers would you recommend?MeatWagon: Total NOOB!! 4x8 cnc plasma table build in progress here!
Reply:Originally Posted by SeanMurphy265I have the 4.0 kit that I am reworking. I originally used 2x2 square mild steel for my rails. When I cut my table down to a 5'x5' I ordered 2x2 aluminum square tubing for my new rails. I cannot begin to describe how much better the carriages slide on the aluminum rails over the steel rails. I never felt the table ran as smooth as it should have, but now I can tell it will run much better.
Reply:Hey Folks,After looking at the mesa cards and linuxcnc.org, I've redone my trusty electronics comparison chart.I figure that with keling motor drivers and no Mach license, not including my time, I should save a little less than $600 vs. the DragonCut kit from candcnc.com. That's a lot of money no matter how you slice it and time is a resource that I actually have a fair amount of. Thanks for the heads up tensaiteki! I'm sure I would have been up and going sooner with the kit, but I can't resist the challenge and the savings of going the mesa route. Starting tonight, I'm off from my "real" job for a whole week, so hopefully I can get a lot knocked out on the frame during that time.MeatWagon: Total NOOB!! 4x8 cnc plasma table build in progress here!
Reply:Cool. I received my 5i25 and THCAD-300 from Mesa last week. Got the latest version of LinuxCNC burned to a disk (make sure you burn it at the slowest speed) and am trying to run a latency test to see if my old P3 machine will be up to snuff to run it (I recently upgraded it's memory from 256K to 1.5GB for a whopping $17 expenditure on eBay). You can run Ubuntu/LinuxCNC off the Live CD in a limited fashion to see how it works with your system before actually installing it, which is what I'm currently doing. I was getting an error about Local APIC being disabled by the BIOS, but it looks like something that can be enabled in the terminal with a simple command. Hoping to have some time to mess with it this week...
Reply:Originally Posted by dbotosCool. I received my 5i25 and THCAD-300 from Mesa last week. Got the latest version of LinuxCNC burned to a disk (make sure you burn it at the slowest speed) and am trying to run a latency test to see if my old P3 machine will be up to snuff to run it (I recently upgraded it's memory from 256K to 1.5GB for a whopping $17 expenditure on eBay). You can run Ubuntu/LinuxCNC off the Live CD in a limited fashion to see how it works with your system before actually installing it, which is what I'm currently doing. I was getting an error about Local APIC being disabled by the BIOS, but it looks like something that can be enabled in the terminal with a simple command. Hoping to have some time to mess with it this week...
Reply:Originally Posted by MeatWagonThis is the frame for one of the table's sides. Can anyone tell me why my fillet welds are getting gouged out like this from time to time?
Reply:Originally Posted by pipelinerare you using co2 or 75/25?
Reply:Good luck this week as you are able to work on this plasma table, it is fun seeing your progress. Whenever you hit a wall with the electronics there is a ton of great help on the linuxcnc forum. They were always quick to help above and beyond what I expected. When I ran the latency numbers on the computers I used for lcnc they were not great but I was told that using the mesa 5i25 and the 7i76 that is was not as important as if you were running directly off of the computer. I have been very happy with the performance of my machines, acceleration and top speed exceeded my expectations by a long shot. Keep posting pics it is great to see it moving along.
Reply:Well, here's the progress I made last week with my time off:It was a long week. Spent a lot of time scratching my head, but I'm happy with how it's coming along. Surface is square to within 1/16" with the entire base tacked together and the angle braces and top corners welded.For details and more pics, visit the blog.Canner, thanks a lot for the encouragement! I'm glad you're enjoying following along. I bit off a lot when I took this on. Never done anything like this before and the people on this forum have been really excellent!Also, all the electronics have arrived and I have Ubuntu and LinuxCNC installed on the PC Ill be using (which I got for $70 at the government surplus barn... SCORE!), so expect some progress there over the next couple weeks. Thanks for looking!MeatWagon: Total NOOB!! 4x8 cnc plasma table build in progress here!
Reply:Originally Posted by MeatWagonHey Sean, I think I read your build thread on the everlast forum before I started mine. Looked good. What have you made with your table?-Adam
Reply:You guys have done some awesome work. Many thanks for sharing. I do have a totally CNC plasma table noob question, if I can lead up to it this way.--I'm thinking for us garage hobby folks that a 4x8 table is just too doggone big. --I do understand that most sheet goods come in 4x8 size. --I suspect that most of the items I want to cut will be less than 4'x4' actual size. Is there a way I could have my cake and eat it too? Can I have a 4x4 setup with an open 'edge' that enables me to feed in half of a 4'x8' sheet for those occasional times when I have a 4x8 stock on hand? Obviously I would have to have temporary sawhorses or some other type of support for the overhang. This would allow me to minimize storage when not actually using the CNC machine. Anybody been here before?thanks, zip.
Reply:Originally Posted by zipzitYou guys have done some awesome work. Many thanks for sharing. I do have a totally CNC plasma table noob question, if I can lead up to it this way.--I'm thinking for us garage hobby folks that a 4x8 table is just too doggone big. --I do understand that most sheet goods come in 4x8 size. --I suspect that most of the items I want to cut will be less than 4'x4' actual size. Is there a way I could have my cake and eat it too? Can I have a 4x4 setup with an open 'edge' that enables me to feed in half of a 4'x8' sheet for those occasional times when I have a 4x8 stock on hand? Obviously I would have to have temporary sawhorses or some other type of support for the overhang. This would allow me to minimize storage when not actually using the CNC machine. Anybody been here before?thanks, zip.
Reply:Hi ZipzitWhat you are wanting is very easy to build you just have the top surface of the material grate higher then your water table or no water table. The smaller table is my 4’ X 4’ and the other is the 4' X 8’ I am building now. Mine have both ends open like Meatwagon said his was. Mine have a parking space at one end so the torch is out of the way for loading material table lengths are acually 6' and 9'. Attached ImagesLast edited by acourtjester; 09-09-2013 at 08:02 PM.Reason: corrections
Reply:I got my Mesa IO and BO cards installed and tested in LinuxCNC. Spent quite a bit of time reading the manuals etc before putting power to anything. Used the pncconfig wizard in LinuxCNC to configure the hardware and got the motor moving! I also hooked up a home switch to test the 7i76's field io. That also seemed to work. Here's how I wired up the 7i76 for testing:Field power can take 8-32 volts, so I just put the 9v battery on it for testing. While it definitely wasn't plug and play, setting up LCNC with the mesa hardware hasn't been as bad as it could have been so far. We'll see how it goes once I'm trying to get everything dialed in when it's set up on the table. Pretty excited to have it moving! Now I just need to get the rest of the fab done on the table...MeatWagon: Total NOOB!! 4x8 cnc plasma table build in progress here!
Reply:I've used three methods to detect the plate height. I started with torque sensing. Works great on plate but can cause flex issues with gauge materials. I then installed a laser sensor. Worked fantastic for shiny gauge material like galvanized and aluminum but was miserably inaccurate for non-reflective material. I then upgrade to ohmic touch. After a bit of false start due to a software incompatibility combined with bad ohmic board I finally got it sorted a year ago and it has worked flawlessly. I prefer the ohmic touch of all three. Understand that it does have to make electrical contact to work so painted material my be problematic. Unlike torque sensing it sets the z value on retraction so even if it flexes the sheet it measures when the plate returns. My control uses torque sensing if it fails to get a good ohmic touch contact so I don't have to worry that the plate is pristine.Here's a thread that shows everything required for the upgrade:http://weldingweb.com/vbb/showthread.php...ng-ohmic-touch
Reply:So, I've finally got the base of the table welded up! I also have the risers tacked on and I've decided on some unorthodox wheels. I'm going to cut off the goofy u channel brackets I made for the castering wheels and put leveling feet in the corners. With those retracted, it rolls really nicely balanced on the two big straight wheels in the middle. Feels really good to finally have the frame pretty much done. In my next blog post I'll be drilling and tapping the rails. Any advice on getting the v-rail and gear racks mounted just right? Thanks again for all the input and support!MeatWagon: Total NOOB!! 4x8 cnc plasma table build in progress here!
Reply:Hey folks! Took a little break to go get married. That went great and I'm back so I thought I'd post a little update on the plasma table project. I cut the U channel brackets off the corners and mounted the leveling feet. Pics are here.I've tacked on the mounting plates for the rails and finish welded the risers to the base of the frame. Next up is mounting the gear racks and v-rail to the rails. I'm pretty excited and nervous to start this phase of the project. Anybody have any advice for how to mount these precisely level to the 2x2 tubing? I've got a caliper and a digital level that I'm planning on using... Thoughts?Thanks for reading!MeatWagon: Total NOOB!! 4x8 cnc plasma table build in progress here!
Reply:Hello friends,I finally got my table up and running about 6 weeks ago. The process was infinitely more challenging and time consuming than I had imagined. Huge respect for all the other scratch builders out there without whom I never would have gotten this thing running. Special thanks to the guys on the forums at linuxcnc.org. Without John Thornton's page, I never would have figured out how to configure my torch height control. There are still lots of (mostly cosmetic) things I want to do to the table, but after all these months, I feel good just having it up and running. Here's a video of my machine cutting out an aluminum instrument panel for a Cessna 180. Thanks again for this great community and as always, any advice would be very much appreciated.meatwagon
Reply:Originally Posted by forhireI've used three methods to detect the plate height. I started with torque sensing. Works great on plate but can cause flex issues with gauge materials. I then installed a laser sensor. Worked fantastic for shiny gauge material like galvanized and aluminum but was miserably inaccurate for non-reflective material. I then upgrade to ohmic touch. After a bit of false start due to a software incompatibility combined with bad ohmic board I finally got it sorted a year ago and it has worked flawlessly. I prefer the ohmic touch of all three. Understand that it does have to make electrical contact to work so painted material my be problematic. Unlike torque sensing it sets the z value on retraction so even if it flexes the sheet it measures when the plate returns. My control uses torque sensing if it fails to get a good ohmic touch contact so I don't have to worry that the plate is pristine.Here's a thread that shows everything required for the upgrade:http://weldingweb.com/vbb/showthread.php...ng-ohmic-touch
Reply:Nice looking another example of if there is a will there is a way. For those who have the will there is help out there to help you on the way with a project like this.DIY CNC Plasma table USB BOB Price THCHypertherm 65Everlast PowerTig 255 EXTMiler 180 Mig13" metal latheMill/ DrillECT, ECT, |
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发表于 2021-8-31 22:06:46