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Trying to resurrect my R2

Discussion in 'Mods and Upgrades' started by Joseph Stevens, Jul 6, 2021.

  1. Joseph Stevens

    Joseph Stevens New Member

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    Both of the thermistors are giving incorrect readings, and I've pretty much determined that the mainboard is faulty.

    My question is, are my only choices to use one of partsbuilt's custom Z boards or a stock R2 board? Can I instead use a newer 32 bit board instead?

    EDIT: what I sort of have in mind is to completely de-Robo3D-ize the R2 and use another firmware like klipper
     
  2. Omar Basha

    Omar Basha New Member

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    Lol... great minds, I was thinking of doing something similiar, since there's nothing special about the robos core design it shouldn't be too much of a problem me thinks to change to an skr or something like that. I've never done anything like this and since I got a zmorph, the robos being standing. I'd be interested in watching what you do.

    Sent from my SM-N970F using Tapatalk
     
  3. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    You can do either. Most of the 3D printers out there (at least ignoring delta style) can't really use a 32-bit board (like a RAMBO or others) to the full extent. They are fine on the 8-bit control boards. Doesn't mean it won't work (they will)*.
    Rip out and replace the control board. Depending on the one you get you may not need the Raspberry Pi any longer and others will still benefit from that as the front-end.



    *but if it works fine and full-speed on the 8-bit board you don't gain anything by replacing it with a better one. The other mechanical parts limit your max speed and acceleration regardless of the electronics controlling it
     
  4. Jerome Helbert

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    I am actually in the middle of this. After fighting with extrusion issues the main culprit finally became evident when the extruder stepper would just click and wiggle back and forth, almost certain the stepper driver died.

    I have an SKR 2 arriving tomorrow with TMC2209s. I've decided to do away with the uptown and downtown boards and wire everything individually back down to the mainboard (it helps that I was already in the middle of a conversion to a Bondtech BMG and Mosquito hotend, so I've already designed and printed parts for the gantry to use these and it gives me a bit more room)

    I'm also dumping the external power brick and will be mounting a 120V receptacle/switch in place of the current 4-pin DIN input. Then feeding that into an internal 350W 24V power supply.

    I've already been using Klipper with the stock R2 mainboard for the last month or so, and it looks pretty trivial to adapt the generic skr2 config over to my specific implementation.

    I will attempt to take pictures during the process and will try to put together a writeup, but I can't guarantee a write up very soon. The next month or so has too much going on.
     
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  5. Lance Weston

    Lance Weston Active Member

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    When my Robo power supply died I went to an external 24v 15amp which mostly worked. I would get random stops. I have since gone to a 24v 25 amp supply and everything is okay. I suspect that the relatively low frequency at which the heaters go from full current to zero and back presents the problem. I do not think these cheap Chinese supplies were designed for it.

    There is already a lot of heat in the base of the Robo with no ventilation. I would be leery of adding more.

    Please keep us up to date with your progress.
     
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  6. Jerome Helbert

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    Yeah, the temp down there is a bit of a concern (although with the stock equipment I had not noticed it getting too warm, but adding a 360W supply down there is going to be a significant increase in dissipated power.) I'm planning to keep an eye on temps and if it becomes an issue I will look into adding an exhaust port and fan.
     
  7. Lance Weston

    Lance Weston Active Member

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    If you start taking the main board in and out be careful. The print head cable has an exposed metal shield running under the main board.. I cut the metal shield off with a scissor where it is under the main board so that it does not short out anything on the main board. I wonder how many people have lost their main boards just by moving the R2 around.
     
  8. Jerome Helbert

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    Well I am replacing the mainboard and the printhead cable (I assume you mean the ribbon cable), so not much of a worry there :)

    Interestingly though, I just had a standard ribbon cable between my mainboard and the print head, nothing shielded.
     
  9. Lance Weston

    Lance Weston Active Member

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    I made a print head cable before I realized that I could buy them from Partsbuilt.com. For cable to have that nice arc, I cut strips of from a large sheet of really heavy paper. I then layered the strips into an arc and taped them together. I taped the ribbon and hotend heater cables to the strips and then covered with he same cable protector (from Amazon) that Robo used. It works and looks okay but not great.

    The shielding is to meet FCC requirements meant to protect twin lead TV's with antennas from electronic radiation. In today's world it can be ignored.
     
  10. Jerome Helbert

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    Well I got everything installed and it is running - and got zero pictures of any of the build process. I was under a time crunch to get it running so I could batch out some prints that need to be done by Thursday.

    I will try to put together some info when I am less busy (prob a few week away), but to summarize I am incredibly happy with the printer now (omg, TMC2209s are the greatest thing ever - they are so silent I didn't even think the printer was working at first!) I'm still tweaking print settings, but otherwise the printer is running great. While it doesn't seem excessively so, with the onboard power supply now the electronics compartment is a bit warm after a multi-hour print with the bed at 90C. I am planning to drill a pair of 60mm holes in the bottom and adding 60mm fans with screens for an inlet and exhaust - this is in addition to taller feet for the print to get more airflow underneath.

    Here is a list of the major modifications:
    [​IMG]
    • Replaced the Hexagon hotend with a Slice Mosquito configured with a 50W heater and a PT1000 temp sensor.
      • I replaced the stock metal hotend clamp with a new mounting plate for the mosquito (Mosquitos are threaded mounts)
    [​IMG]
    • Replaced the Robo extruder/stepper with a Bondtech BMG-M and a pancake stepper (this required a new plate to be added to the top of the gantry block to mount the BMG-M to
      • I shot myself in the foot a bit with the BMG-M, it uses screw to mount instead of the groovemount, and this put me into a situation where the mounting plate needed screws going both up and down, and the assembly is a bit "tricky" now...
      • I went with the BMG-M instead of the standard BMG because I am working on a new gantry design that would let me directly mount the mosquito do the BMG-M and significantly reduce the filament path between the two.
      • The plate is serviceable for now at least
    [​IMG]
    • Eliminated the Uptown and Downtown boards and directly wired everything to the SKR 2 (with a connector break just above the extruder so that I can still remove it
    [​IMG]

    The printer is now 100% 24V, so I also got to replace just about every fan and light I had in the system with a 24V version, but everything is now controlled by the SKR and capable of PWM via klipper. The hotend fan only turns on when needed, the 80mm fan blowing over the SKR 2 only turns on when the steppers are active, the lights are dimmable, etc. When the system is not actively printing it is dead quiet.

    I haven't installed it yet, but I am also working on a new hotend mount that will let me use a Precision Piezo Orion for bed level sensing. This device mounts between the hotend and the extruder and signals with something like 5 micron accuracy when the nozzle contacts anything. This will replace the garbage IR sensor.
     
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  11. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Looks good.

    I don't use autoleveling myself -- well the SeeMeCNC delta I do, but only because trying to manually level a delta is a migraine in the making. None of the other FDM printers (5) use it.
     
  12. Jerome Helbert

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    I hadn't been either until I switched to klipper and the default R2 config used the IR Sensor as a virtual endstop. I really like the approach, but just couldn't get it to work reliably (for obvious reasons.)

    One thing I like about the piezo is that there is no z offset. Where it homes to is the exact 0 position. Ideally with this I can swap nozzles and or do anything that might affect the z offset and the piezo handles it automatically.
     
  13. Lance Weston

    Lance Weston Active Member

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    Wow, this is one impressive upgrade. I have two suggestions. There is a block stl somewhere that mounts under the stepper where your fan is now. It improves performance. I will look for the stl if you can't find it. I have found that a fan blowing air over the drivers is a must. The steppers turn on and off with every print and go through a thermal cycle. There will be some number of thermal cycles where the chip separates and dies. The cooler they are kept the better.

    Please keep us up to date.
    .
     
  14. Jerome Helbert

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    I believe I've found the stl you are talking about and its in my queue of things to upgrade.

    Also, there is an 80mm that kicks on anytime the steppers are active and blows directly over them.
    [​IMG]
     
  15. Jerome Helbert

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    In hindsight I wont be able to use that block as is... I mounted my RPi underneath the z stepper. I should be able to throw together an equivalent design without too much hassle that can work around it
     
  16. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    By all means let us know how it works for you.
     
  17. Jerome Helbert

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    For the gantry upgrade, I am thinking about designing something a bit more along the lines of the ulimaker and replacing the twin 6mm rods for each axis with a single 8mm rod and using these XY bushing blocks on the ends . Then I think I can move the extruder down / hotend up into the same "plane" as the rods (instead of having them above/below as they are now.)

    I think this can eliminate a significant amount of moving mass on the gantry.

    I've also toyed with the idea of designing it as an adapter for something like the EVA system, then it would be trivial to use just about any hotend or extruder on the market. I haven't decided if this is a good idea yet or not, or if that design already has to make too many concessions to accommodate a linear rail that we dont need to worry about.
     
  18. Jerome Helbert

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    I forgot to mention that I've ditched the x/y endstops and am using the tmc2209s sensorless homing functionality. Basically you set the drive current relatively low and then slowly move the print head towards the edge. The drivers detect when the carriage can't move any further and stalls out. There is a whole tuning procedure for it where you characterize the max and min sensitivity so that its reliable, but without damaging anything.

    Currently it ends up triggering when the carriage itself bumps into the xy blocks, and I would rather have it trigger when the xy blocks bump into the belt gears on the 8mm rods, so that something I plan to incorporate when I redesign the whole gantry assembly.
     
  19. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    I did exactly that on the R1 series except I just let it run all the time.
     
  20. Jerome Helbert

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    I wasn't planning to have it auto-toggled, but klipper did it automatically when I entered it into the config as a controller_fan. I do have to admit it that it is nice to have the unit be completely silent when on but not actively printing.
     

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