Want to confim DuetWifi is right for my setup



  • Hey guys!

    I have a large printer that I've built that currently uses 2.8a NEMA23 steppers from Openbuilds using external drivers and a Smoothieboard but my printer makes a fair amount of noise, around 70db according to my phone so I need to bring that noise level down if I want to run this in my apartment for weeks on end lol

    After searching around it seems like the DuetWifi "should" be able to drive my steppers, but the software limit is 2.4a with 2.8a being the max allowed by the driver. What I'm looking to nail down definitively is if I can drive my steppers at 2.8a with heatsyncs and 2 120mm fans for intake and exhaust pulling air through a roughly shoebox sized compartment where the boards would be.

    Considering I'd be looking to get a DuetWifi, Duet5 expansion and a 7" Panel Duet, I want to make sure it will be a bullet proof setup before I pull the trigger since its a bit of an investment just to bring the noise down 🙂

    Also, I'm pretty sure what I want to do won't be a problem with the Duet5, but I'm gonna mention in case I've misunderstood something. I'll be using 2 steppers for Y and 2 for Z and one for X plus 2 nema 17 steppers for extruders, totalling 7 steppers in use. With that expansion board and some cofig tweaks, this shouldn't be a problem right?



  • I use the duet wifi to run those motors, and they are at 2.4a(3a in the future) and run great. I have a fan cooling the back side of the Duet Wifi. Yes the Duet Wifi + Duet5 can do everything you want to do.



  • So running these particular steppers at 2.4a is no problem and won't likely skip steps? If that's the case I think I'll be good to go 🙂

    Edit: Also, I'm not sure what your setup is, but it's worth pointing out that my Y axis is moving around is roughly 8.4kg of mass so I'm not sure if this amount of weight will cause a skip at a point where the direction will change quickly?



  • @efficientAF:

    So running these particular steppers at 2.4a is no problem and won't likely skip steps? If that's the case I think I'll be good to go 🙂

    Correct. Just like I said over on reddit. 🙂

    @efficientAF:

    Edit: Also, I'm not sure what your setup is, but it's worth pointing out that my Y axis is moving around is roughly 8.4kg of mass so I'm not sure if this amount of weight will cause a skip at a point where the direction will change quickly?

    You're looking at a ~10% reduction in torque running those motors at 2.4A. I doubt that would cause skipped steps, but reducing acceleration by ~10% would result in a 10% lower motor load. So worst case you're looking at a slightly reduction in acceleration relative to your current setup.



  • Check this.

    https://docs.google.com/spreadsheets/d/1w60BUzpiZ6Gjqt8P8pSoqq4r4j0qxhxQVSbI5c0SoWw/edit#gid=0

    here is the data sheet for Openbuilds motor
    http://www.motechmotor.com/products_detail.php?id=159&cid=71&page=2

    I copied the google doc so I could edit it and replaced one of the other motors with this data and then change the info at top to match my or your machine.



  • @elmoret:

    Correct. Just like I said over on reddit. 🙂

    You're looking at a ~10% reduction in torque running those motors at 2.4A. I doubt that would cause skipped steps, but reducing acceleration by ~10% would result in a 10% lower motor load. So worst case you're looking at a slightly reduction in acceleration relative to your current setup.

    lol you found me! I trust you won't begrudge me some additional confirmation 🙂 I was hoping David would chime in and throw out a bunch of math I don't understand, yet find comforting nevertheless lol

    Yeah, with the amount of mass that's being moved around I don't think I'll get above 100mm/s anyways so if things will be stable under that speed and with the slight reduction in torque and/or acceleration, it sounds like it'll be fine.

    I went ahead and ordered a DuetWifi, Duet5 and the PanelDue w/ 7" LCD. Hopefully the noise reduction will be substantial enough that I can put my noise problems to bed finally and start printing some giant stuff!



  • @jmjcoke2:

    Check this.

    https://docs.google.com/spreadsheets/d/1w60BUzpiZ6Gjqt8P8pSoqq4r4j0qxhxQVSbI5c0SoWw/edit#gid=0

    here is the data sheet for Openbuilds motor
    http://www.motechmotor.com/products_detail.php?id=159&cid=71&page=2

    I copied the google doc so I could edit it and replaced one of the other motors with this data and then change the info at top to match my or your machine.

    I'm not even going to pretend I know how to read this lol How does load factor into this?



  • What diameter are your pulleys?



  • @jmjcoke2:

    What diameter are your pulleys?

    The page says 18mm, but I can measure them when I get home to be sure.

    http://www.ebay.com/itm/3GT-Timing-Pulley-20-Teeth-Bore-8mm-Pitch-3mm-GT3-Open-Belt-Rubber-Wide-9mm-CNC-/321932116824


Log in to reply