1. Got a question or need help troubleshooting? Post to the troubleshooting forum or Search the forums!

Partsbuilt R2 stepper driver upgrade

Discussion in 'Mods and Upgrades' started by Lance Weston, Jan 14, 2021.

  1. Lance Weston

    Lance Weston Active Member

    Joined:
    Jun 2, 2018
    Messages:
    580
    Likes Received:
    196
    I had put larger higher current steppers on the x and y axis. I was using the same A4988 stepper drivers that the Robo board used. I set the reference to 1.2v for 1.5 amp drive. I put the extra large heat sinks on and was running fine. The drivers on both machined failed about the same time, a few months. They were running hot which accelerated the thermal cycling failure time.

    I put in Chinese clone DVR8825 drivers and at first set to 16 micro steps for compatibility. I did the fast decay mod because I was only running 1.6 amps. I got the same results as the Robo drivers. I then switched to 32 micro steps. Did not seem to make any difference in the print, but the machines went quiet. The difference was amazing. I do not know why it makes it quiet, but it does. The DVR8825 runs much cooler the Robo drivers.

    It is worth buying the Partsbuilt board just for making the printer run quiet.

    Update:
    I modified the DVR8825 plugin boards because I read that they were using clone chips running at 1/2 freq (16 kHz). I ordered a current probe for my scope. to view the signal and verify nice smooth steps. I need two current probes to look at the differential current between the two windings..DUH. I did however find that the chips were running at the full 32 kHz so I removed the modification. They run fine and cool. I will find another current probe, look at the differential current and report my findings. It will take awhile.
     

    Attached Files:

    #1 Lance Weston, Jan 14, 2021
    Last edited: Jan 24, 2021
  2. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
    Staff Member

    Joined:
    Feb 21, 2013
    Messages:
    23,668
    Likes Received:
    7,316
    Depends on what you want.

    Hottest steppers I have used were on the 6' delta printer we have. I had to put heat sinks on the motors... the stepper drivers kept up OK, but those NEMA 23 steppers were... hot.
     
  3. Lance Weston

    Lance Weston Active Member

    Joined:
    Jun 2, 2018
    Messages:
    580
    Likes Received:
    196
    I

    I am using 17HS8401 steppers. They are 48 mm rather than the 40 of Robo and have lower inductance and higher current (1.7 amps) but run faster. I have heatsinks and fans on my x,y and extruder steppers. I am currently driving them at 1.6 amps. I have not micro stepped the extruder to 32 steps rather than the current 16 because I do not see the point, same with the z axis.

    Took me awhile to figure out the stepper drivers were failing. The LCD's first started acting flaky and I can not figure out the connection. The drivers on the Robo board will also fail from thermal cycling eventually. It will just take longer because the temp is lower. You can run things hot forever, but you can not cycle the temp by turning them off/on without eventual failure.
     
  4. EmbraceNext

    EmbraceNext Member

    Joined:
    Jun 23, 2018
    Messages:
    32
    Likes Received:
    5
    How did you upgrade/replace the drivers on the R2 main board?
     
  5. Lance Weston

    Lance Weston Active Member

    Joined:
    Jun 2, 2018
    Messages:
    580
    Likes Received:
    196
    You can not modify the Robo system board. Partsbuilt.com sells a system board that allows you to change the drivers. I use DVR8825 drivers with 32 rather than 16 steps and up to 2a current.

    Eventually all stepper drivers will fail due to thermal cycling on the die. Being replaceable is a big plus.
     
    #5 Lance Weston, Dec 22, 2021
    Last edited: Dec 22, 2021
  6. EmbraceNext

    EmbraceNext Member

    Joined:
    Jun 23, 2018
    Messages:
    32
    Likes Received:
    5
    Ah ok! I read somewhere that getting .9 had to get the amperage increased.
     

Share This Page