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what is the minimum resolution that can be achieved?

Discussion in 'Tutorials' started by Chiru, Dec 16, 2015.

  1. Chiru

    Chiru New
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    Dear all,
    What will be the minimum resolution for the open build lead screws.? Can I achieve micrometer movement resolution using the setup. I want to move the axis in micrometers like in miniature or micro actuators. Please share your ideas and views.
    Thank you.
     
  2. Rob Taylor

    Rob Taylor Veteran
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    For that kind of resolution, you're going to want high-end ballscrews and Harmonic Drive servomotors, both of which are more or less backlash-free (and hundreds of dollars per part!). Any old machine tool should be able to hit 1-2 thou, which is 25-50 micron, so it shouldn't be beyond the realms of possibility to improve that a little.

    While you can theoretically hit a high precision with consumer-grade (OpenBuilds) parts, your accuracy (ie. repeatability) is going to be non-existent due to flex, backlash, magnetic hysteresis, etc. OBPS stuff is good to 0.1mm, and should be good to 0.025mm, but hitting 0.001mm with any reliability is going to be a challenge.

    Micro actuators have very small ranges of motion for a reason. Positional error is delta precision (accuracy) over delta motion (RoM or unit length), hence why it's typically quoted in microns per mm or thou per inch. The smaller your total motion, the less cumulative error you're going to have within that range. This is why highly accurate machine tools are absolutely monstrous, with relatively tiny tooling areas. You build a machine of a size to get your required error, then make the part volume as small as possible. So you end up with 5 ton machines operating on a six-inch cube.

    Edit: also this probably needs moving to General Talk.
     
    Jag-UK likes this.

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