hypothetical cnc machine with stepper motors

Discussion in 'The Projects Forum' started by vane, Apr 4, 2007.

  1. vane

    Thread Starter Active Member

    Feb 28, 2007
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    supposing i was gonna' try to make a cnc machine with stepper motors would the circuitry be easy to make? thanks
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
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    Kinda depends on your experience and resources.
     
  3. Papabravo

    Expert

    Feb 24, 2006
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    Probably not. Stepper motors have generally poor speed torque characteristics and are subject to electrical and mechanical resonances. They can require large standby current to hold their position. The biggest problem is that they are normally controlled open loop. Real CNC machines use DC electric servo motors with a supply of 300 VDC or larger and are controlled closed loop.

    Still, if your burning to try then knock yourself out.
     
  4. hgmjr

    Moderator

    Jan 28, 2005
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    The fact that you are asking for suggestions would indicate that you might benefit from experimenting with stepper motor design on a small scale as a means of familiarizing yourself with the different types of stepper motors and driver circuits. This will allow you to experience firsthand some of the characteristics of stepper motors and thereby be in a better position to judge their suitablity for use in implementing cnc machines.

    hgmjr
     
  5. kender

    Senior Member

    Jan 17, 2007
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    It depends on the type of the machine. Did everyone just assume a mill?

    Steppers are impractical, when you need to apply force and torque. Steppers are practical, when something needs to be postioned without a lot of force and acceleration. So, steppers would work for a laser cutter or CNC drill-press.
     
  6. Papabravo

    Expert

    Feb 24, 2006
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    An engraving table with a diamond drag tool or a single flute cutter was my thought.
     
  7. vane

    Thread Starter Active Member

    Feb 28, 2007
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    i make rc planes and wondered if i could make a machine that cut out the parts acurately, really want is a two axis machine that i could attach tools to to draw, cut vinyl, cut wood etc, thanks
     
  8. kender

    Senior Member

    Jan 17, 2007
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    Speaking of RC airplanes, once I've used a CNC hot-wire foam cutter made with stepper motors.
     
  9. vane

    Thread Starter Active Member

    Feb 28, 2007
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    cool! i wish i had one of them!
     
  10. vane

    Thread Starter Active Member

    Feb 28, 2007
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    ive been thinking about getting an old printer and instead of the ink pump i have a little tool that goes down and drills a hole, it may be good for a start.
     
  11. vane

    Thread Starter Active Member

    Feb 28, 2007
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    can i have it? :)
     
  12. thingmaker3

    Retired Moderator

    May 16, 2005
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  13. kender

    Senior Member

    Jan 17, 2007
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    That was one of a kind machine put together in early 1990s by graduate students of Stanfors Aero&Asto department. I'll post the pictures, if I get a chance to take them.

    BTW, here's a link to somebody's home-built cutter: http://www.8linx.com/cnc/day1.htm
    and this page has some nuce CAD drawings of foam cutters http://www.tekoa.com
     
  14. vane

    Thread Starter Active Member

    Feb 28, 2007
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