4 stepper motor controller without using expensive chips

Discussion in 'The Projects Forum' started by vane, Apr 15, 2007.

  1. vane

    Thread Starter Active Member

    Feb 28, 2007
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    is there any way i can make a 4 stepper motor controller that is controlled by a computer connector like the printer cable without expensive silicone chips? im gonna be making my own cnc milling machine with stepper motors
     
  2. Papabravo

    Expert

    Feb 24, 2006
    10,140
    1,789
    Silicone is used for breast implants.
    Silicon is used for integrated circuits.

    I don't see how you're going to control stepper motors without using some kind of silicon chips. Were you planning on using "cheap" vacuum tubes?

    A CNC milling machine using stepper motors sounds like a losing proposition. If you had said DC electric servos you would have a bit more credibility.
     
  3. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    If you take a look at stepper motor controllers, you will see that there's not much to them, even if you want to fool around with half- and micro-stepping. The problem is that steppers don't have good torque characteristics, and have limited speed ranges. 5000 steps/sec sounds like a lot until you realize that it's 200 steps/revolution. That's only 25 RPM. The steps are too coarse to use as is, so you also have to gear the motors down to get resolution.

    After that, you need a computer to keep track of the number of steps, and be able to move the mill through a cut and return to the initial position. That's true of servos, too, but you get better performance.
     
  4. windy

    Member

    Apr 19, 2007
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    To answer your question, Yes you can control a stepper motor using a parallel port on a computer, boosting the output with transistors. There are transistor packs in ic format that will handle the load and have flyback diodes built in, to long ago to remember numbers. Most of the open source programs for CNC use controllers and therefore these controllers are the best way to go. Last time I checked a 4 stepper controller based on the Pic controller chips was around a 100 clams. If that is to much, the machine time involved in the making of the equipment will kill you. I could see this setup for hole drilling opporations, but not milling opporations, for those you will need at least 1/2hp motors on the axis drives.(servo)

    The open source code is G and M code programming stuff and you will have to make your own advanced coding most of the time in C or C++
     
  5. thingmaker3

    Retired Moderator

    May 16, 2005
    5,072
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    Power of the motors depends on size of the mill. I've seen a mills with a seven foot table used to make bulldozer parts and/or aircraft landing gear. 1/2hp would not be enough for those monsters.

    100 oz inch steppers will work for a "mini-mill" such as one might buy from Taig or build from Gingery's books.
     
  6. vane

    Thread Starter Active Member

    Feb 28, 2007
    181
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    from what ive heard so far, some stepper motor controllers cost £80, what i meant was is there anyway i can possibly make one for cheaper, even with my inexperience with complex circuit drawing
     
  7. Papabravo

    Expert

    Feb 24, 2006
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    If your time is worth nothing, then you can build anything your heart desires. £80 doesn't sound like much compared to what it will take to build your own.
     
  8. thingmaker3

    Retired Moderator

    May 16, 2005
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    If you are interested in learning through building, then a stepper motor controller would be as good a project as any. If you just want to get your CNC mill up and running as quickly and cheaply as possible, try finding used or surplus parts.
     
  9. cnc1

    New Member

    Apr 25, 2007
    3
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    there is some wisdom in what thingmaker3 is saying here...i believe that if you can build it...you can fix it.!

    advise: get MACH 3 to control the stepper controller via your computer it is fairly easy to configure.

    and for good value get SHEET CAM (to create the tool path)it is definitely the way to go in 2.5D milling
    and for cad i use RHINO 3
    i use 3 steppers of 150 oz each. they are a little slow on rapids but hey! there s always other important things you can do while CNCing a part.. IE. video games ..
     
  10. vane

    Thread Starter Active Member

    Feb 28, 2007
    181
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    i am purposely trying to make it go really slowly because i havent got a milling machin bit, im just using a little ordinary drill bit so it has to go really slowly, i have a software for making the stepper motors go called Kcam 4, im going to be making some really big stuff like plane sides, what software offers a large "work area" on the screen?
    im going to be using this cnc machine for my D&T final piece which is going to be an rc plane, maybe i could aask my teacher if the cnc machine could be part of my mark :) anyway i wont bore you any more

    vane
     
  11. vane

    Thread Starter Active Member

    Feb 28, 2007
    181
    0
    i'll nick the ps2 :)
     
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