Step motor losing steps - no load


Results 1 to 4 of 4

Thread: Step motor losing steps - no load

  1. #1
    Member
    Join Date
    Mar 2012
    Location
    Serbia
    Posts
    7
    Downloads
    0
    Uploads
    0

    Question Step motor losing steps - no load

    Hello everyone,

    I finally started building my first CNC machine. And I done it and I am proud of it. However I have one problem that I failed to manage. I notice when I run some G code that have strait lines it works ok, sometimes I notice that it doesn't return to same position but I was still experimenting with speeds and acceleration so I thought that was the problem.

    However I noticed that with code that doesn't have straight lines, but rather contours and G code is point next to point generated by MasterCAM i loose steps a lot! For test I took only part of G code that lasts 1min 17 seconds with adjustments 400mm/s and 20mm/s^2, 80 steps per millimeter and I notice that I lose about -0.5 millimeter when I return to same position x,y,z(-2,0,0). And I always loose steps in same direction!

    To diagnose this problem and make sure that problem is in electrics not mechanics I took off stepper motor, I put straight part of the shaft in horizontal position at (-2,0,0) and started G code. After it finished the straight part of the shaft wasn't horizontal, but rather at some angle (30-40 degrees) which is half millimeter on the pitch of 5mm. If I put it to run 1000mm, motor rotates and finish in the horizontal position (5mm pitch, so one full revolution, 400 steps per rotation, 80 steps per millimeter).
    Also to make sure that correct signals are coming to the stepper driver I made circuit that counts steps with PIC microcontroller, divides steps by 8 and show on the display. I start G code and when I finish code at -2,0,0 at screen from microcontroller I also have -2.0 for X axis. So I don't loose steps at all for signal part. I also tried to lower acceleration to 2mm/s^2 just to make sure that acceleration is not the problem. I also tried to lower speed. I always lose steps with this code in attachment.

    I use driver DM556, and power supply SW-13A-36V. Stepper motor is NEMA 23, 57HS112 (3A and 3Nm).

    I don't have any idea left, so if someone have any suggestion, please free to replay. Thank you in advance

    Similar Threads:
    Attached Files Attached Files


  2. #2
    Community Moderator ger21's Avatar
    Join Date
    Mar 2003
    Location
    Shelby Township
    Posts
    35447
    Downloads
    1
    Uploads
    0

    Default Re: Step motor losing steps - no load

    Try setting the microsteps to 1/8 or 1/10 (1600-2000 steps/rev). If you are getting resonance, this should help.
    Also, when a motor is not mounted to anything, it's more susceptible to resonance, so it may actually be worse when it's not on the machine.


    What control are you using?

    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
    Member
    Join Date
    Mar 2012
    Location
    Serbia
    Posts
    7
    Downloads
    0
    Uploads
    0

    Default

    Quote Originally Posted by ger21 View Post
    Try setting the microsteps to 1/8 or 1/10 (1600-2000 steps/rev). If you are getting resonance, this should help.
    Also, when a motor is not mounted to anything, it's more susceptible to resonance, so it may actually be worse when it's not on the machine.


    What control are you using?
    I will try that, I tried allready 1/4 also but its same. I use mach3.

    Wont i get a lot less power with 1/10?



  4. #4
    Member CitizenOfDreams's Avatar
    Join Date
    Nov 2012
    Location
    USA
    Posts
    1068
    Downloads
    4
    Uploads
    0

    Default Re: Step motor losing steps - no load

    Is your STEP signal polarity correct? Try inverting it (in Mach3 "Ports and pins" menu) and see what happens.



Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  


About CNCzone.com

    We are the largest and most active discussion forum for manufacturing industry. The site is 100% free to join and use, so join today!

Follow us on


Our Brands

Step motor losing steps - no load

Step motor losing steps - no load

Step motor losing steps - no load