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  1. #1
    Join Date
    Feb 2008
    Posts
    48

    Mach 3 motor tuning

    Hi, I've searched a few times on the forum but cannot find a solution.

    My problem is I have just purchased a new CNC linear machine, I am using Nema23 motors but cannot get them to move any axis at all, even messing around in Motor Tuning on Mach 3 cannot get them to move at all, just low & high pitch noises.

    Anyone point me in the right direction of how to calculate the figures I need for motor tuning?

    Thanks in advance.

  2. #2
    Join Date
    Mar 2003
    Posts
    35538
    Start with very, very low numbers (10 veocity and 1 accel) )and see if you can get the motors to spin. If not, you have a problem somewhere.
    Gerry

    UCCNC 2017 Screenset
    http://www.thecncwoodworker.com/2017.html

    Mach3 2010 Screenset
    http://www.thecncwoodworker.com/2010.html

    JointCAM - CNC Dovetails & Box Joints
    http://www.g-forcecnc.com/jointcam.html

    (Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)

  3. #3
    Join Date
    Jul 2007
    Posts
    887
    Have you ran the Drivertest program to verify that the computer is up to the task of running Mach3? If yes, have you set up you Ports&Pins to match the hardware, ie the step and direction signals are going to the right place. If you aren't getting any pulses then check that the LPT-port adress set in Mach3 is matching the adress of the port in your computer. And lastly, you are using a proper LPT-port aren't you. Using a USB<->printer port will never ever work.

  4. #4
    Join Date
    Feb 2008
    Posts
    48
    I had it running ok on another machine but this new machine is a lot heavier, I can get a noise from the motors but it just will not turn the threads.

    The motors are wired in series and I've got the Vref at 3 & Pfd at 2.3, I'm not sure if moving the figures higher will make it work better.

  5. #5
    Join Date
    Feb 2007
    Posts
    4553

    Smile More information is needed in order to help you.

    Nenetwork,

    It sounds like the steppers are stalling.

    How big and how heavy is the new machine?

    What thread pitch are the lead screws?

    What stepper drivers are you using?

    What ounce or nm rating are the steppers?

    More information is needed in order to help you.

    Jeff...
    Patience and perseverance have a magical effect before which difficulties disappear and obstacles vanish.

  6. #6
    Join Date
    Feb 2008
    Posts
    48
    Hi,

    The motors are Nema23 and are 0.88NM

    The machine is 20kg all together

    The thread pitch is 3mm

    The stepper driver is a bipolar 3 axis

    Thank you for your help, as you can tell I'm not that clued up on the specs

  7. #7
    Join Date
    Jul 2007
    Posts
    887
    Are you sure you haven't just reversed the step and direction signals? If so the motor would take a single step every second time you change direction. And to verify that the it's not just a matter of the motors being too small for this new machine disconnect them from the machine (mechanically) and see what happens.

  8. #8
    Join Date
    Feb 2007
    Posts
    4553
    What brand stepper driver, how many amp output?

    What voltage and amperage power supply?

    Jeff...
    Patience and perseverance have a magical effect before which difficulties disappear and obstacles vanish.

  9. #9
    Join Date
    Feb 2008
    Posts
    48
    First off I would like to thank you's for taking your time to help me.

    The cnc board is a http://www.easy-cnc.com/3axisdriver.html and I cannot find the output amount

    My Powersupply is

    13.8v dc

    current 3a continuos, 5a duty cycle & 7a surge


    The motors run alright when not connected to the mounts.

    Thanks.

  10. #10
    Join Date
    Feb 2007
    Posts
    4553

    Question

    What is the stepper motor amperage spec?

    Jeff...
    Patience and perseverance have a magical effect before which difficulties disappear and obstacles vanish.

  11. #11
    Join Date
    Mar 2008
    Posts
    3655
    Quote Originally Posted by nenetwork View Post
    I had it running ok on another machine but this new machine is a lot heavier, I can get a noise from the motors but it just will not turn the threads.

    The motors are wired in series and I've got the Vref at 3 & Pfd at 2.3, I'm not sure if moving the figures higher will make it work better.
    Your .88 Nm motors are 125 oz in. The NEW HEAVY machine weighs about 45 pounds total. (What machine was a lot lighter?) Those motors should be powerful enough to at least move such a little axis somewhat. The PSU voltage might be a little low though.

    When the motors were running on the other machine, was it the same computer/Mach3/driver combo or what was it?

    What exact motors are these? What exact driver board? What exact machine?

    You ARE using a real parallel port from inside computer aren't you?

    What about the cable between computer and driver. Is it the same cable as used on other machine? Is it a "straight thru" cable?

    CR.

  12. #12

    MDL-2-TR-UN

    The minimum spec' motor is 2Nm
    http://www.worldofcnc.com/products.asp?recnumber=194
    or
    Assembled with our Ballscrews you can use 1Nm motors...

  13. #13
    Join Date
    Feb 2008
    Posts
    48
    Everything I have is what I used before, the connection is a parallel port on my computer. The previous machine was made out of wood, it was very light.

    I thought it may have been the motor tuning at first but then I thought it was either the Power supply or the torque on the motors.

    The motor amps are 2a peak (series) or 4a peak (parallel), I am running mine as series 2a

  14. #14
    Join Date
    Feb 2007
    Posts
    4553

    Red face

    NOT ENOUGH MOTOR TORQUE
    Patience and perseverance have a magical effect before which difficulties disappear and obstacles vanish.

  15. #15
    Join Date
    Feb 2008
    Posts
    48
    So I should wire them in parallel to increase the torque?

  16. #16
    Join Date
    Feb 2007
    Posts
    4553

    Post

    The problem is twofold.

    1: Your stepper driver is only 2.5 amp output.

    2: The stepper motors are to small.

    Best solution, get these stepper motors.

    http://www.kelinginc.net/KL23H276-28-4B.pdf

    If you want to get some speed out of your router you may want to get a new power supply also.


    Jeff...
    Patience and perseverance have a magical effect before which difficulties disappear and obstacles vanish.

  17. #17
    Join Date
    Mar 2008
    Posts
    3655
    Quote Originally Posted by jalessi View Post
    He has the motors wired series, that would cut the torque in 1/2.

    NOT ENOUGH MOTOR TORQUE
    NOT SO!

    The motor has the same torque whether wired Series or Parallel. Now UNIPOLAR wiring would cut the torque by about 25%.

    Series wiring allows the most torque at low speed. Parallel wiring allows the most torque at higher speed.

    If everything is electronically the same on new machine as old--The problem must lie in the new machine somewhere.

    CR.

  18. #18
    Join Date
    Feb 2007
    Posts
    4553
    Crevice Reamer,

    You are 100% right about the low speed high speed torque, I stand corrected.

    Jeff
    Patience and perseverance have a magical effect before which difficulties disappear and obstacles vanish.

  19. #19
    Join Date
    Feb 2007
    Posts
    4553

    Question

    nenetwork,

    I still believe the motors are way to small to do the job.

    Are the motors round or square?

    Jeff...
    Patience and perseverance have a magical effect before which difficulties disappear and obstacles vanish.

  20. #20
    Join Date
    Mar 2008
    Posts
    3655
    Quote Originally Posted by jalessi View Post
    nenetwork,

    I still believe the motors are way to small to do the job.

    Are the motors round or square?

    Jeff...
    I agree! Those motors ARE very low power. But it would seem that they would at least turn the axis a LITTLE.

    CR.

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