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Recommendation requested for a smaller & lighter NEMA 17 extruder servo.

Discussion in 'Mods and Upgrades' started by BrooklynBay, Mar 19, 2019.

  1. BrooklynBay

    BrooklynBay Active Member

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    I was using a roll of Inland filament last week, and the diameter of the filament kept getting wider as the roll was used. It eventually clogged my machine, and did some damage. I had to replace a piece of Capricorn tubing going into the hot end, the nozzle, and now I've noticed that the servo has no power. It was struggling for an extended period of time trying to force filament through. Since I have a direct drive set up, I want to use the strongest servo which is available with a 39MM thickness which is the size of my stock servo. I've narrowed it down to three options.

    This one appears to have the highest torque, and requires 1.5 Amps: https://www.moonsindustries.com/p/n...tepper-motors/ms17hd2p4150-000004611110008900. There are two other options. One is similar but it requires 2 Amps. I think that it's not as efficient since the torque rating is the same. The other option is a 1 Amp model with a slightly lower torque rating. I'm attaching a PDF spec sheet for all three servos.
     

    Attached Files:

  2. BrooklynBay

    BrooklynBay Active Member

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    What is the current rating of the stock servo? Could an A4988 stepper driver supply 2 Amps without an adjustment?
     
  3. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    No clue what the specs are on the stock stepper, but with the heatsink attached the A4988 stepper drivers are good to 2A with fan cooling as well.

    https://www.pololu.com/product/1182

    Yours may be generic, but the specs are the same
     
  4. BrooklynBay

    BrooklynBay Active Member

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    Thanks for your reply. To narrow down the options, is a 1 Amp servo with a slightly lower torque rating about the same as a 1.5 Amp with a slightly higher torque rating? The stepper is capable of providing 2 Amps so a 1 Amp servo might run a little cooler. I wanted to get the highest torque without over working the stepper so maybe the 1.5 Amp version should be fine?
     
  5. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Your call. Me? I would err on the side of more torque :)
    If you don't need the extra torque it hurts nothing (you won't use it).
    Usually the ones with more torque are physically larger, but if you find one that fits it will work.
     
  6. BrooklynBay

    BrooklynBay Active Member

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    The stock servo has less torque than the rare Earth servos, and would bind if the adjustment screw was just a drop too tight. The company (Flexion) recommended that I use a servo with a higher torque rating since my stock servo was just border line as far as torque. I'm sure that both of these servos will work but if I could get a little more torque in the same size servo then it should work fine to handle many different types of filaments. My stock servo worked fine until it got damaged.
     
    mark tomlinson likes this.

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