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  1. #1
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    ballscrew and gear reduction

    could someone tell me what the ratio would be if i went with 32mm dia and 32mm pitch to achieve 10mm pitch? im guessing 3:1 or am i wrong

    edit: also goal is to aim for acceleration rather then speed for 3D work and with the ballscrew being almost 3 meters long and driven with a rotating ballnut would you say 32mm is needed? again acceleration is important here not speed although a decent amount of speed is still required.

    thanks

  2. #2
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    Re: ballscrew and gear reduction

    I can't see any information about the software that will control the machine.Its quite normal to have a box in the configuration stage of the machine that will allow you to tell the controller how many steps per millimetre there are.So you need to determine how many (if any) microsteps per revolution there will be and then add the information about the reduction ratio and the thread pitch.I don't really understand why you would want to select 10mm but if that is the necessary amount,wouldn't a 10:32 reduction be appropriate?Or any other multiple of 5:16.I can remember a machine that had 57.33 steps per millimetre and it worked OK.

  3. #3
    Community Moderator Jim Dawson's Avatar
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    Re: ballscrew and gear reduction

    The motor torque is really the limiting factor. The position resolution is just a matter of steps (or micro-steps) per revolution. My old router had a 40mm x 40mm pitch ball screw with a 1.3:1 timing belt drive reduction. I had the steps/rev set at 0.01mm resolution.

    If you are using stepper motors, then you want to run them in the lower end of their RPM range to have maximum torque, and thus maximum acceleration.
    Jim Dawson
    Sandy, Oregon, USA

  4. #4
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    Quote Originally Posted by Jim Dawson View Post
    The motor torque is really the limiting factor. The position resolution is just a matter of steps (or micro-steps) per revolution. My old router had a 40mm x 40mm pitch ball screw with a 1.3:1 timing belt drive reduction. I had the steps/rev set at 0.01mm resolution.

    If you are using stepper motors, then you want to run them in the lower end of their RPM range to have maximum torque, and thus maximum acceleration.
    Using nema 34 closed loops 10Nm on all 3 axis. Its the pulley ratio and pitch size I'm unsure on too. I was going with 2525 screws with 2:1 but I think 32mm might be best?

  5. #5
    Community Moderator Jim Dawson's Avatar
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    Re: ballscrew and gear reduction

    Quote Originally Posted by reefy86 View Post
    Using nema 34 closed loops 10Nm on all 3 axis. Its the pulley ratio and pitch size I'm unsure on too. I was going with 2525 screws with 2:1 but I think 32mm might be best?
    Again on my old router, my cross axis had a 2525 ball screw, and a similar stepper, it had a timing belt drive with a 1:1 ratio. It sounds like you have plenty of torque available, so it's just a matter of setting the steps/rev to your desired resolution. Most important is how much mass you are trying to accelerate, this is your limitation. If you know the mass, you can do the math to calculate the max acceleration with the available torque.

    https://www.linearmotiontips.com/cal...e-ball-screws/
    Jim Dawson
    Sandy, Oregon, USA

  6. #6
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    Re: ballscrew and gear reduction

    Quote Originally Posted by Jim Dawson View Post
    Again on my old router, my cross axis had a 2525 ball screw, and a similar stepper, it had a timing belt drive with a 1:1 ratio. It sounds like you have plenty of torque available, so it's just a matter of setting the steps/rev to your desired resolution. Most important is how much mass you are trying to accelerate, this is your limitation. If you know the mass, you can do the math to calculate the max acceleration with the available torque.

    https://www.linearmotiontips.com/cal...e-ball-screws/
    He is planning on using a rotation Nut so not much mass to move
    Mactec54

  7. #7
    Community Moderator Jim Dawson's Avatar
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    Re: ballscrew and gear reduction

    Quote Originally Posted by mactec54 View Post
    He is planning on using a rotation Nut so not much mass to move
    So the other moving parts of the system, like the carriage, don't count as moving mass?

    Thank you for playing, please try again.
    Jim Dawson
    Sandy, Oregon, USA

  8. #8
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    Re: ballscrew and gear reduction

    Quote Originally Posted by reefy86 View Post
    Using nema 34 closed loops 10Nm on all 3 axis. Its the pulley ratio and pitch size I'm unsure on too. I was going with 2525 screws with 2:1 but I think 32mm might be best?
    25mm Ballscrew will be fine if you are using a rotating nut, 32mm is always going to be better but that is a course pitch you have to deal with, you will have to think about what the resolution will be and how smooth you want your machine to run
    Mactec54

  9. #9
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    Re: ballscrew and gear reduction

    Quote Originally Posted by Jim Dawson View Post
    So the other moving parts of the system, like the carriage, don't count as moving mass?

    Thank you for playing, please try again.
    Your link you posted is only referring to Ballscrew and Motor torque.

    He would need different information for using a Rotating Ball Nut, not what you posted
    Mactec54

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