Adjusting stepper drivers

Discussion in 'Calibration, Help, and Troubleshooting' started by Alex9779, Mar 20, 2016.

  1. Alex9779

    Alex9779 Moderator
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    So I gotta ask how are everyone's stepper drivers voltages set?

    I set them according to the build manual to between 0.55V and 0.60V. All of them.
    When I did that I already thought about that there are two motors connected to the Z stepper driver so there should be some different value set at least for Z because two motors share the current.

    I knew I read something on G+ the days the very first got their boxes and I found one message with Tim Elmore's values which were 0.576/0.253/0.654/0.510V (XYZE).
    That values sound pretty reasonable to me. X to given range, Y less because of the gear ratio, Z increased because of two motors sharing the current and E to slightly less that given range not sure yet why but it also works good.

    At first after the build I had no issues all steppers set to about 0.575V but the Y axis had some resonance issues and sound when travelling at travel speed from front to back.
    Turning the Y down removed that sound and the box is now really quiet. Still waiting on the clone Astrosyn Dampers I was able to order in Germany. Directly from Astrosyn I would have to order at least 10 pieces...

    So again I'd like to see some other values and opinions about setting the stepper drivers...
     
  2. R Design

    R Design Well-Known Member

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    Hey @Alex9779, can tuning the X/Y drivers influence print quality?

    What might we expect to see in the prints if "too high" or "too low"? By resonance, were you talking only about a sound or also about some wobbles in the print?

    In particular, I'm not happy with the edges of holes in parts that I print (where the print head turns the corner abruptly). Looking for solutions for that.
     
    #2 R Design, Mar 20, 2016
    Last edited: Mar 20, 2016
  3. Rob Heinzonly

    Rob Heinzonly Well-Known Member

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    Mine are at 0.55/0.44/0.66/0.57 (XYZE). However I'm still struggling with the settings of the Y-axis. At some occasions the Y-Axis won't move at all. I only hear a sort of click when moving the Y axis manually. It looks like if the motor isn't getting any power because I can move the carriage by hand quite easy.
     
  4. mike01hu

    mike01hu Well-Known Member

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    Rob, I assume you have checked the grub screw tightness as someone else had that problem and found the screws were not tightened enough. A quick check of the motor and driver can be made by removing the belt and making a Y-axis move from the front panel, so that the motor turns. You can grip the motor spindle/pulley to check the torque.
     
  5. Alex9779

    Alex9779 Moderator
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    There are effects on print quality. I am not an expert and this is my first printer I am really dealing with those things.
    As far a I know if the current is too high the motor skips steps. That means that lets say you tell the motor to make 10 steps but it will do 12 or 15. On a print you see that by shifting layers.
    If it is far too low then the motor won't move at all.
    I have no experience what happens if it it not far too low but low. I assume then something like skipping steps can occur but the opposite. The motor might not move all steps given. So you might say move 10 steps but actually it only move 5 or 8.
    A high current also leads to high motor temperatures and lower life span of all the included components driving the motor...
     
  6. Alex9779

    Alex9779 Moderator
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    Maybe follow what @mike01hu said, it sounds plausible. I checked my machine after I did the new settings, and my Y axis is half of yours now and my motor moves perfectly with enough torque I can't move it by hand when powered...
     
  7. Rob Heinzonly

    Rob Heinzonly Well-Known Member

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    @mike01hu : I think I did check it, but I will double check later. Thanks for the advice.
     
  8. mike01hu

    mike01hu Well-Known Member

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    On my current printer (K8200), I also changed the grub screws for pointed ones and, with a hand drill and bit sharpened to the same angle of the screw point, I made a small indentation on the shafts so that the screws had a solid location; this was not easy on the hard shafts. As I have yet to see what the BB kit has, this may not be an easy option but it is important to ensure that you have a secure shaft to pulley connection as, even with the relatively light mass of the carriage, there is an inertia effect that will work against that connection, particularly with direction changes and any slack in the drive chain will show up in print quality.

    Another issue for stepper motor driven systems is that the movement is a series of jerks i.e. vibration and we all know the effects of vibration on fixings! Fortunately, magnetic hysteresis effects in the motor dampen some of this effect, You can also use thread lock on the shaft, NOT the screw, to improve shaft-lock but you will need an extractor to pull the pulley off the shaft if you ever needed to. There is not much torque reaction from the X and Y carriage, so the last fix is not essential but anything to improve the solidity of the mechanical path is good but if you choose this option make sure the shaft and pulley are clean from grease or oil.
     
  9. R Design

    R Design Well-Known Member

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    My first printer too.

    Funnily enough I'd understood exactly the opposite: that if the current was too low the motor would skip steps and do 8 or 9 instead of 10.

    You're probably right.

    I'm wondering if "too high" means that the nozzle moves too aggressively, making vibrations...?
     
  10. Alex9779

    Alex9779 Moderator
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    Is just a matter of how you call it: skipping or adding.
    I tried it out..
    If the current is too low it "skips" steps: the motor does less steps than it should.
    If the current is too high it "adds" steps: the motor does more steps than it should.
     
  11. R Design

    R Design Well-Known Member

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    Great info. Thanks.

    I watched Tom's Guide on calibrating steppers.... He points out that you may need more juice in the steppers during a print (than during lab testing) if the nozzle hits a hard bit of plastic.....
     
  12. Alex9779

    Alex9779 Moderator
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    I am still tweaking... The values didn't prove to be so good... The Z had little clicking sound while doing anything, had to turn them down. The Y did the strange sound now not when moving fast at travel speed but when doing slow outline moves around 20mm/s. Turned that up again too...
    I am going to watch Tom's Video again...
     
  13. EpicFail

    EpicFail Active Member

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    Reviving an old thread because Im wondering where the good values are at..
    I looked at my drivers and found they were a,, at 1.5... so yeah too high. Knocked them down to the top values listed by Alex, but im worried i may be too low now. Since the thread was never updated... What is a good setting that has been somewhat agreed upon? Or are the drivers a crapshoot and I just have to keep turning 1/32 of a rotation to figure it out?
     
  14. EpicFail

    EpicFail Active Member

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    Seriously, because this is my 5th attempt at a rocket, and its started shifting layers by the time it gets past the tail fins. Im losing time, sleep, and my sanity having to wait for it to fail.
     
  15. mike01hu

    mike01hu Well-Known Member

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    I am afraid it's the "suck-it-and-see" approach but should be within the parameters that Alex set with perhaps a little more for the Z driver. Do check that you don't have a mechanical issue in that the Z axis is binding at the position you are having problems with. Lubricate your rods and move the axis with the LCD over its full length a few times and watch what happens.
     
  16. Jasons_BigBox

    Jasons_BigBox Well-Known Member

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    Hi EpicFail,

    this is the point where I cause chaos with my theory on driver voltages..........

    I had z-axis issues where it was not moving the z-axis down on some layers and trying to print over the top of the last layer. The end result was that a 20mm cube was coming out at 19mm or less. The thread below details what I found:

    https://forum.e3d-online.com/index.php?threads/weird-height-variations.1973/

    To cut a long story short, I found that the steppers were missing steps and turning up the voltage made things worse. I reduced the voltage and it's worked fine since. I think we came to the conclusion that the higher voltage allowed higher currents to the motors but limits on the driver boards could stop the motor temporarily.

    A few have had issues with the plug used to connect the stepper to the driver board and have solved it by removing the plug and using the screw in connectors instead.
     
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  17. cez

    cez Well-Known Member

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    I had the same issue as you, followed your example and so far so good :)
     
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  18. EpicFail

    EpicFail Active Member

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    If I am to check the voltage on the PSU, Im going to have to flip this thing on its side and get the bottom unscrewed from it, right? Or is there a ground I can touch the multi-meter to from its current configuration with just the access panel open?
     
  19. Jasons_BigBox

    Jasons_BigBox Well-Known Member

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    I didn't touch the PSU, just my stepper drivers.
     
  20. EpicFail

    EpicFail Active Member

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    Oh yeah I get that, but others in the thread mentioned making sure the PSU was tuned so you could maintain the higher demands,

    What speed did you end up maintaining for your print at your current voltages?

    Considering the BB configuration, it should be a 120mm machine easily. But I think the Ramps and supplied drivers may be under-rated for the mechanical task of doing so.
     

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