CNC advice please

Discussion in 'CNC Machines and Conversions' started by jgarrett, Mar 18, 2018.

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  1. Mar 18, 2018 #1

    jgarrett

    jgarrett

    jgarrett

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    Hello,
    I want to build a stepper motor to control a single axis on a small milling machine.
    I would like to be able to vary direction and speed from a "box" without having to use a PC.
    Is this doable?? Any help would be greatly appreciated.
    Cheers,
    Julian
     
  2. Mar 18, 2018 #2

    blighty

    blighty

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    sorry, I have no advice for you, but I have been wanting to do this my self for a while. would be useful for many applications.

    like you, I would like a small box that you can plug a stepper into and with a rotary knob speed it up slow it down. job done, nice and easy.
    would also like two switches, so when your thing hit one switch it would reverse the direction. hit the other switch then come back, so on and so forth.
    probably an easy thing to do with Arduino and some simple programing. but being simple I cant program Arduino's.
     
  3. Mar 18, 2018 #3

    blighty

    blighty

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    found something that might get you up and running.
    did a search for "arduino stepper motor speed control potentiometer" lots came up. vid below has what you want. has the code for it @4:28. but nothing about how to wire it up. also he used a little stepper. there must be boards for bigger steppers.

    under the same search you will also find step and direct projects.

    [ame]https://www.youtube.com/watch?v=gSnGQjxpYP4[/ame]
     
  4. Mar 18, 2018 #4

    BaronJ

    BaronJ

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    Hi Julian,

    It would be interesting to know exactly what you want the motor to drive ? Most people don't want a complicated solution to what maybe is a simple DC motor and variable voltage power supply.
     
  5. Mar 18, 2018 #5

    jgarrett

    jgarrett

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    Baron,
    I want to use it to drive the X table on my mill (24").
    Yes you are right...I probably could use a DC motor and gears to do the same thing.. It's just that I plan to get into CNC at some point and this would get my feet wet..
    Julian
     
  6. Mar 19, 2018 #6

    Cogsy

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    You're right, it likely would be fairly easy to get an Arduino to control in the way you want, even with the auto reversing limit switches. Unfortunately it would take time, which I don't have at the moment, otherwise I'd be prepared to give it a go. I'll keep it in mind for a later date though.
     
  7. Mar 19, 2018 #7

    Buchanan

    Buchanan

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    This is what I use . It has forward and reverse as well as start and stop. Also oscillate between forward and reverse. You will also need a 48 volt power supply. The prices are for multiple pieces, 2 and 4 of each. They work really well.

    cnc.JPG
     
  8. Mar 19, 2018 #8

    rodw

    rodw

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    If you just want to drive 1 axis, you could use my Arduino controller which supports linear motion.
    http://www.homemodelenginemachinist.com/showthread.php?t=25091

    But if you wanted to get into CNC, you could consider Grbl on an Arduino which has a subset of full blown CNC Gcode control.

    For an Aussie, steppers online are hard to beat for Stepper motors. Grab a NEMA 23. They also sell power supplies too but a better option might be to grab a Meanwell 48v Power supply from Power Supplies Australia. a 7 amp supply would be enough for 3 axis into the future.

    I've had good results from Longs Motor DM542A stepper controllers from eBay that look similar to the image above. They have an elephant logo on them. There are a few other brands of dubious quality with a similar part number.

    If you poke around on eBay you should be able to find a 48v to 12 V buck power supply to Power the Arduino.

    Feel free to PM me as I'm in AU.
     
  9. Mar 19, 2018 #9

    blighty

    blighty

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    this is exactly what i was after.

    [ame]https://www.youtube.com/watch?v=stxFDjTuzkA[/ame]
     
  10. Mar 19, 2018 #10

    BaronJ

    BaronJ

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    Hi Julian,

    That is what I thought, See this link
    http://www.homemodelenginemachinist.com/showthread.php?t=23130

    Whilst I hear what you say about going CNC, I offer these thoughts:-
    Using a stepper motor to drive the table is not always a good idea ! The reason is simply because a stepper motor moves in discrete steps.
    Consider this, suppose your machine table moves 2 mm per turn, as mine does, most stepper motors have 200 steps per turn, that means that your table will move 0.01 mm for each step. Depending upon the tool you will have discrete cuts at these intervals, this causes a banding effect on the work surface. Not always acceptable !

    There are methods of minimising this effect, micro stepping, gearing etc. DC motors and servo motors don't suffer this problem.
    Stepper motors are great at positioning with repeatability and accuracy.
     
  11. Mar 19, 2018 #11

    jgarrett

    jgarrett

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    Baron and others,
    After a lot of deep thinking I'm not sure that at my age I want to tackle something like that,,, I will probably just go with the DC motor option,
    Cheers,
    Julian
     
  12. Mar 19, 2018 #12

    Buchanan

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    It has the advantage that there is no extras required,like programming or PC.
    I have two that have run hundreds of hours on an industrial machine. They also switch on from "cold" instantaneously.
     
  13. Mar 20, 2018 #13

    Rndmann9

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    Check into a gshield. And an arduino. If you want a servo solution
     
  14. Mar 20, 2018 #14

    Herbiev

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  15. Mar 21, 2018 #15

    Buchanan

    Buchanan

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    Yes , that is the motor driver. you still need a step and direction pulse generator and a 10 amp dc power supply 24/48 volts. The pulse generator can be a PC, aduino or the other board in my first post. It has a lot of very useful features in a small simple package that needs no programming.
     

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