SOMD – Lowrider Plasma CNC

New Home Forum LowRider Your Builds – LowRider SOMD – Lowrider Plasma CNC

This topic contains 48 replies, has 11 voices, and was last updated by  Chris 1 week, 5 days ago.

Viewing 30 posts - 1 through 30 (of 49 total)
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  • #62437

    Bryan
    Participant


    My plasma table has been in the works for about two months and it is at the point where I can show it off without fear that I won’t finish the project.

    Specs
    Working area is 4’x5′ with a footprint of about 5’x6′. The 4′ (about 50″ actually) was the critical dimension because I did not want to have to rip stock down to get it to fit on the table. I settled with 5′ on the length because I value the garage space more than the few times I imagine I will be cutting an entire sheet. Since the table supports 6′ of length, I can easily cut a full sheet by splitting the jobs and shifting the stock in between.

    Hardware
    I am using the standard RAMPS 1.4 stack with DRV8825 drivers and NEMA 17 steppers (84 oz-in I believe)

    The plasma cutter I am using is the Lotos LTP5000D, 50A, pilot arc start with the standard torch and running off of 220V. For such a low cost cutter, it has surprised me with its cut quality, but I have much to learn yet about reducing dross and minimizing part cleanup. I have ran 22/4 shielded alarm wire for all of the steppers and grounded the shielding inside a metal junction box. So far, I have not seen any problems due to noise from the plasma cutter. However, I use a Netgear powerline adapter to get internet to the garage and rebroadcast it with a secondary router for wifi, and the plasma totally messes the signal up when the machine is turned on.

    The focus of the machine is for plasma cutting thin (14 GA) sheets of steel, but easily switchable for routing with replacement of the slats for 2 sheets of 0.75″ MDF. (Yes, I understand the potential hazards of mixing sawdust and hot bits of metal). I already have a 28″x28″ MPCNC for most of that work, but always had been itching for something larger. The MPCNC will probably get resized in half for a better focus on rigidity.

    Software/Firmware
    Flashed onto the Mega is GRBL 1.1f. I wanted something more geared towards CNC with better user interfaces than the LCD screen or other 3d printer oriented solutions. I have tried CNC.js via the Raspberry Pi 0W, and it worked until I turned the plasma cutter on and it takes out my wifi. I needed a solution that would not require networking, and I could control from the CNC. I am currently running bCNC on a Raspberry Pi 3 with a 7in touch LCD and it seems to satisfy all of my needs. It is fast and responsive (doesn’t require network connection to send commands which results in double jog movements or otherwise no response), and the GUI works well on the Pi3, whereas cnc.js would not. It also has a lot of great gcode editing tools and some limited CAM functionality which is welcomed.

    To-Do
    Create mounting arm for Pi3 and LCD touchscreen
    Cut brackets for drag chain carrier
    Re-cut flat wood pieces out of 0.25″ mdf (lauan is pretty thin)
    Tear it all down and paint everything

    This has been a work in progress where I’ve been learning a lot about welding and metal working in general. Thanks to you Ryan for making this platform that we can take and create things with at such a reasonable cost, and most of all supporting it to a high level. I went all in on the MPCNC two years ago and have a MP3DP as well because I knew this community has a strong base and it’s a great place to hang out (or in my case, lurk).

    Google album with more details, videos as I progress… https://photos.app.goo.gl/WywV1Q9XHMPcCAEk7

    3 users thanked author for this post.
    #62445

    Jeffeb3
    Participant

    This thing is just epic. I love it.

    w.r.t. cnc.js (and if you like bCNC, then that’s fine too):
    You can install a “shopfloor tablet” UI, and then use the pi3 to connect to itself (no networking required):
    https://github.com/cncjs/cncjs-shopfloor-tablet

    Or, since you have a pi3 now, you could also do wired Ethernet.

    As I said in your google photo album, a machine like this can make a lot of money. Cutting signs out of metal and painting them can be big bucks (I think, never tried). I can’t wait to see what you end up doing with it.

    #62452

    Bryan
    Participant

    Yeah, I tried the “shop floor tablet” layout and it was lacking pizzazz. I could re-write the template, but bCNC was there plus it has autoleveling functionality built in, which is awesome. Ethernet is a no-go as well bc the signal all passes through over the electrical connection via the powerline adapter, which becomes useless with all of the noise generated by the plasma cutter on the garage subpanel. Thankfully the controller is ok.

    Plan on doing lots of signs. Going to scour etsy to steal ideas from. Only problem is that the steel sheet prices keep going up 😪

    #62455

    Ryan
    Keymaster

    Dude….dude. HOlywhoa. Yup you now have the entire lineup of V1 tools (zenXY dinner table?) and officially the absolute baddest ass LowRider ever.

    I need a plasma cutter, need as in no projects for it but I wanna play with it!

    1 user thanked author for this post.
    #62474

    Bryan
    Participant

    I do not have a zenXY yet, but a large table one does sound really cool.

    No no, the projects come afterwards. If nothing else, then use it to cut stiffener plates for its own machine. My torch holder is (currently) 3d printed pla, which has started to warp due to the intense heat source right below it, imagine that… So I cut a heat shield for it and problem solved. Next will probably be the XZ plates because why not?

    #62485

    Jeffeb3
    Participant

    Next will probably be the XZ plates because why not?

    Yes. I didn’t know I needed that until right now.

    #62496

    Bryan
    Participant

    Oops… I meant YZ plates.

    #62511

    Jeffeb3
    Participant

    You mean the little ones? Why not all of them?

    #62540

    Bryan
    Participant

    First piece went pretty well, 1/4″ mdf + 14 ga steel is way better than the 0.190″ plywood I had before. Gotta love a machine that can improve itself!

    #62547

    Cap
    Participant

    Awesome – I love that you’re doing this project.  This is something that I want to do later on down the road.  Langmuir systems is building a very similar product (much smaller size) and selling it for around $1000 without plasma cutter.  Link below:

    https://store.langmuirsystems.com/?gclid=CjwKCAjw68zZBRAnEiwACw0eYYiWC__iqrZvObPcyvDpAlguzDA9FSsqvILo-0-FXZ9_0D-ioUloJRoCsVIQAvD_BwE

    What I found really interesting though was their recommended plasma cutters – you can find them under the LEARN tab with the following statement up front.

    the CrossFire™ CNC plasma table was designed as a hobby-level machine to accept a wide variety of available plasma cutters on the market today. The only hard requirement is that the plasma cutter does not use a High Frequency start mechanism in order to initiate the plasma arc. These style of plasma cutters are strictly forbidden for use on the CrossFire™ machine because the High Frequency arc can cause permanent damage to the machine’s electronics components.

    Keep us posted on how this goes – you’ve got me fired up!

    #62550

    Bryan
    Participant

    I did look into the Langmuir system however the size and lack of rigidity were an issue because I wanted to cut wood with this as well. Most plasma cnc designs are not entirely robust. There are no cutting forces seen by the gantry, so they can get away with much smaller carriages.

    I’ve got less than $1200 in this build, plasma included.

    #62555

    Gene buckle
    Participant

    This is excellent!  I’ve the same make/model of plasma cutter that you used on your project.  Did you know they make a straight cutter head intended for CNC?  They run about $100.  It’s basically a straight head instead of the curved one that comes with it.

    It won’t be much longer before I start my build.  Thanks for the nudge. 😉

     

    g.

    1 user thanked author for this post.
    #62556

    Bryan
    Participant

    Thanks. Do you have a link for the machine torch? Only one I could find was about $180. It would be much easier to use the straight torch.

     

    It won’t be much longer before I start my build. Thanks for the nudge. 😉

    Go for it! Can’t wait to see yours

    #62558

    Gene buckle
    Participant

    Whoops – it looks like I mis-remembered the price, or they jacked it up by $80 since I last looked a couple of years ago.  I went to the Lotos Technology website and yep, it’s $180. 🙁

     

    g.

     

    #62613

    Cap
    Participant

    Agree, way better option to build your own.  Less expensive and a much more capable machine.  The other site was only interesting because they’d consolidated a list of plasma cutters which weren’t high frequency starts.

    Do you have pics of how you shielded the electronics package?  I’d like to get a closer look at that.

    Really fired up about what you’ve done, I think its awesome.

    #62665

    Bryan
    Participant

    Do you have pics of how you shielded the electronics package? I’d like to get a closer look at that.

    I ran 5 pin aviation panel connectors for all everything. The fifth pin allows me to ground the shielding to the connector, and then inside the box I can connect them all together. Inside the box is kind of messy, I really don’t have enough space to lay everything out neatly and the tape I was using to hold the RAMPS board is having a hard time sticking…

    All of the green wires are the shielding ground leads, as well as a ground from the power supply. Everything is ground to the junction box, but I didn’t follow through with grounding the table or driving a ground rod in the floor yet because I haven’t had any issues (that I can tell, at least). If I notice a problem, that is what I’ll end up doing.

    Behind the power supply in the box is a buck converter to power the Raspberry Pi 0w in the bottom. As stated above, I’m no longer using the Pi 0, but a Pi 3 now directly. The buck converter module allows me to power the Pi via the sole power supply, because the Mega can’t supply enough current for everything.

    Really fired up about what you’ve done, I think its awesome.

    Thank you! I appreciate it.

    2 users thanked author for this post.
    #62703

    Cap
    Participant

    Thanks Bryan, appreciate the photos and the detailed explanation!

    #62704

    Cap
    Participant

    One more question, how are you physically connected to the plasma cutter to send it commands?  I read back thru the post but must have missed it if it was in there.  Thanks

     

    #62705

    Bryan
    Participant

    One more question, how are you physically connected to the plasma cutter to send it commands? I read back thru the post but must have missed it if it was in there. Thanks

    Right now the only connection is via the 3 pin connector on the front of the plasma to trigger the torch via spindle on/off commands M3/M5. When the cnc is controlling it, I disconnect the connector that comes from the torch (button) and plug in the connector I made that is connected to a 5v relay.

    Current setup lacks a torch height controller (THC) which would monitor arc voltage and vary Z height to compensate for warping and unlevel cut surfaces. Those modules cost $250+ so I’m trying to figure out if I can make one and use it with GRBL.

    1 user thanked author for this post.
    Cap
    #62719

    Jeffeb3
    Participant

    Current setup lacks a torch height controller (THC) which would monitor arc voltage and vary Z height to compensate for warping and unlevel cut surfaces. Those modules cost $250+ so I’m trying to figure out if I can make one and use it with GRBL.

    That would be a fun add on. You’ll have to solve measuring high voltages, not shorting through a microcontroller and then injecting height commands into grbl. All great puzzles.

    #62733

    Cap
    Participant

    Impressive, thanks for the explanation. Where does that plug into the RAMPs stack?  I’m really interested in this, thanks for your patience for my follow up questions!

    Have a good one

    #62747

    Bryan
    Participant

    Relay is plugged into Servo 4 on the RAMPS stack. Relay is active low, so I had to set a flag pre-flash in the GRBL config to allow for a ground signal to turn the plasma on instead of the typical 5v high.

    #62754

    Cap
    Participant

    Man, I wish I understood that! Really simple if one knows what they’re talking about, I’m sure.  Thanks

    #62860

    Gene buckle
    Participant

    The connectors you’re using for the steppers look to be microphone connectors. 🙂

     

    g.

    #62861

    Aaron
    Participant

    The connectors you’re using for the steppers look to be microphone connectors. 🙂

    They look more like what’s commonly called aircraft/aviation connectors. 4 pin xlrs wouldn’t be bad either though, they’re commonly used to deliver power to camera gear too.

     

    #62863

    Gene buckle
    Participant

    Not an aviation connector.  Threaded area is too short and there’s no place to put a lock wire in.  Regardless, it’s a good connector choice for the application you’re using it for. 🙂

     

    g.

    #62866

    Barry
    Participant

    Not an aviation connector. Threaded area is too short and there’s no place to put a lock wire in. Regardless, it’s a good connector choice for the application you’re using it for. 🙂

    g.

    I read that and started having cannon plug PTSD flashbacks.

    #62893

    Gene buckle
    Participant

    If it’s any consolation, I’ve got somewhere around 6, 125 pin bulkhead connectors to wire – so it’s a cannon plug flash-forward. 🙂  I’m dragging my feet on building an automatic wire cutter. 🙂

     

    g.

    #62962

    Bryan
    Participant

    Project is taking a little bit of a turn. I’ve decided to switch over all of the control boards and software to run LinuxCNC. After quite a bit of research, there’s more to a THC than just moving the torch up and down. When cutting corners, heat buildup can cause the sensed voltage to rise, which tells the controller to move the torch down, causing it to dive into the material. LinuxCNC has plenty of support for integrating THCs, where GRBL does not.

    There are other factors at play in my decision as well, but I’ve got more money than time at the moment and just want to do less programming and fiddling. (Yes, I know LinuxCNC will have its fair share of fiddling to go along with it)

    For anyone interested, I just purchased a Mesa 5i25 FPGA PCI card as well as the 7i76 breakout card to replace the RAMPS stack. Also purchased the THCAD-300. The only reason for switching away from GRBL was to integrate the THC and have something more reliable for plasma cutting.

    #62968

    Cap
    Participant

    Thanks for the update, look forward to seeing how it all comes together.

    Happy 4th

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