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Stepper motor speed

Discussion in 'General Talk' started by martin gray, Jan 23, 2020.

  1. martin gray

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    Hi all I have these stepper motors how can I find out or calculate what’s the max rate in mm I currently have it set at 2500 but want to have the machine move a little faster many thanks
     

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  2. ssbxfire

    ssbxfire New
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    What controller are you using? Blackbox or another grbl based controller? See gnea/grbl on how to set $110-112 and $120-122
     
  3. martin gray

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    Hi I have the black box controller using openbuilds software
     
  4. martin gray

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    I know how to set the speed I just need to know how much I can push the stepper motors without blowing them up
     
  5. ssbxfire

    ssbxfire New
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    The document tells you how to tune the values up to the fastest rate your system can handle
     
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  6. martin gray

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    Nevermind
     
  7. David the swarfer

    David the swarfer OpenBuilds Team
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    Hi Martin, Setting the speed higher will not blow up anything so no need to worry there.
    if the step rate is too high for the motors they will just stop and whine.

    max speed is always a tradeoff between max speed and max acceleration. you can get very high max speeds but at the cost of slow acceleration to get there, or you can have insane acceleration at the cost of a much lower max speed.

    max speed for stepper motors is governed by the power supply voltage, the inductance of the coils, and the weight of what it has to move (which directly affects acceleration of course).
     
  8. David the swarfer

    David the swarfer OpenBuilds Team
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    as to how to, the actual process of trying higher speeds, I find a binary search to be the quickest.
    this means doubling (of halving) for each test.
    you are at 2500 now, so try 5000, if that is ok then try 10000, if that fails then try 7500 (half way between the good and the fail speed).

    I got to 7500 on my belt drive OX but there is a sticky spot on the X that would sometimes cause it to lose some steps so I slowed it down to 3500 and it in now utterly reliable. Everything in the mechanics is a tradeoff (-:
     
  9. martin gray

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    haha yeah I’m thinking about the longs motors 57bygh 4.2a versions from eBay they look beefy I’m only cutting acrylic at the moment but have some big jobs coming in the future so might just upgrade now
     

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