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No Torque on NEMA23 Stepper / Arduino CNC

Discussion in 'CNC Mills/Routers' started by magdesign, Apr 12, 2018.

  1. magdesign

    magdesign New
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    Hi

    I built one of the Ooznest OX CNC machines from a kit.
    Running 4pcs. NEMA 23HD56001Y steppers.
    So I sat up an Arduino with a CNC v3 shield and A4988 drivers and GRBL.
    Power supply with 24V 20A.

    All seems to be working so far, but the steppers do nearly have no torque, when I use UniversalGcodeSender to move the motors, I can hold them by hand and they fall through, meaning they do not have any moving torque to move the machine.

    When the motor is in still position, I am not able to move the pulley by hand, its very strong.
    After changing the stepper wiring in various variations (blue, yellow, green, red), reflashing GRBL, setting the stepper driver potentiometer to full power, I am kind of hopeless what else could cause the error.

    I hope someone here can help me!

    Thanks in advance.
     

    Attached Files:

  2. Gary Caruso

    Gary Caruso Master
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    post your grbl settings ("$$" will list them) and just copy and paste here if possible.
    Also what microstep setting do you have the drivers set to?
    When you say it has no moving torque, is it trying? and making screechy noises?
    Full current will probably make those drivers shut down.
     
  3. magdesign

    magdesign New
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    Thanks for your answer.
    The steppers are moving, but have nearly no torque.
    They make sound, also when I connect UniversalGcodeSender the make a quite "brum" sound and block.

    I tried with the standard grbl settings:

    $0=10
    $1=25
    $2=0
    $3=0
    $4=0
    $5=0
    $6=0
    $10=1
    $11=0.010
    $12=0.002
    $13=0
    $20=0
    $21=0
    $22=0
    $23=0
    $24=25.000
    $25=500.000
    $26=250
    $27=1.000
    $30=1000
    $31=0
    $32=0
    $100=250.000
    $101=250.000
    $102=250.000
    $110=500.000
    $111=500.000
    $112=500.000
    $120=10.000
    $121=10.000
    $122=10.000
    $130=200.000
    $131=200.000
    $132=200.000

    as well as with:

    $0=10
    $1=255
    $2=0
    $3=6
    $4=0
    $5=0
    $6=0
    $10=3
    $11=0.020
    $12=0.002
    $13=0
    $20=0
    $21=0
    $22=0
    $23=1
    $24=25.000
    $25=500.000
    $26=250
    $27=1.000
    $30=1000
    $31=0
    $32=0
    $100=26.667
    $101=26.667
    $102=200
    $110=2500
    $111=2500
    $112=2500
    $120=50.000
    $121=50.000
    $122=50.000
    $130=320.000
    $131=525.000
    $132=68.000

    No microstepping jumpers set so far.
     
  4. magdesign

    magdesign New
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    Thanks for the hint with the micro stepping.
    I set all the jumpers to 1/8 microstepping and used the 2nd settings posted above.
    Now, 1 axis is moving with quite strong torque.

    I think the cheap Chinese A4988 drivers are just bad quality, since only one of them unleashes the full stepper power.

    Any recommendation where to buy a good quality GRBL board for 24V Nema23 steppers?
     
  5. Gary Caruso

    Gary Caruso Master
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    Best way imo, is to use the Arduino with independent drivers, the ones openbuilds sells are very good but $40 each, there are cheaper options that are nearly as good, but far better than pololu clones..
     
  6. Giarc

    Giarc Master
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    Those A4988s are drivers for a 3D printer and not really made for a CNC mill. Also, to they have a way to adjust the current? You may not have it high enough. The DRV8825s have a trimpot to adjust current.

    Also, I second Gary's suggestion. Get independent drivers that can actually supply the current your steppers want like the DQ542MAs like Open Builds sells--or something similar. I switched to them from DRV8825s and have never looked back.
     
  7. magdesign

    magdesign New
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    I tried with DRV8825 drivers, but its even worse.
    I could not find any documentation on how to configure GRBL to run smooth with these (set the jumpers to 32 steps, but software config?).
    Maybe someone can help me.

    For the moment I use an Arduino with CNC shield A4988, set to 1/8 steps, but sometimes the steppers stutter and loose steps.

    I was digging around in this forum to search for a good board, I am willing to invest some money into a real good board which supports Nema23 steppers, but there are so many, should I go for grbl, mach3, tinyG and which manufacturer (it should be opensource) ?
    Which boards are really reliable?
     
  8. Gary Caruso

    Gary Caruso Master
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    Keep the Arduino and get real drivers!
    The stuttering is probably just the current adjustment too low.
     
  9. magdesign

    magdesign New
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    I am nearly freaking out....
    i now tried 3 various arduino's an severeal DRV8825 and A4988 drivers.
    I finally found two A4988 which work, burned some and still fiddling to get two of them to work for the Y axis.
    Adjusted the current of the power supply from 23-27 volts.
    Adjusted the drivers.... OMG
    I will order the drivers from Openbuilds and hope they are better........
     
  10. Gary Caruso

    Gary Caruso Master
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    Make sure you have the coils properly identified on your steppers, don't go by color alone, use a multimeter.
    There is no reason to burn things up unless the coils are not paired up. power supply voltage has very little to do with it, 23-27 volts will not matter.
    Some people have had problems with USB cables, make sure it a good cable, start with a short one 1 meter is typical.
    How are you adjusting the driver current? should start low, maybe half way or less and slowly work your way up until motion is smooth.
    What motors do you have?
     
  11. magdesign

    magdesign New
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    The drivers burned because this cheap heatsinks moved under temperature and then shortened the circuit. Its really cheap and bad Chinese stuff (you get what you pay for...).

    First I adjusted the stepper drivers with a voltmeter, at the end when the motors started to stutter, i just moved the pot screws until they where silent.
    I have NEMA 23HD56001Y Bulk Man 3D brand.

    I really think the problem lies on these cheap stepper drivers, because some seem to work now and some do not.

    Since I want to use my CNC the next few years without any trouble, I will now order a USB CNC xPro V3 Controller board. In hope this will be something good.

    Thanks for all your help.
     
    #11 magdesign, Apr 17, 2018 at 4:18 PM
    Last edited: Apr 17, 2018 at 4:26 PM
  12. Giarc

    Giarc Master
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    For the price of the Xpro, you could get DQ542MAs which are much better drivers. Just run them with your Arduino. If one driver does go out in the future, you only need to replace one rather than the whole board (or do a serious unsolder/solder job on the Xpro).
     
    Gary Caruso likes this.

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